CA1229146A - Engine temperature control system - Google Patents
Engine temperature control systemInfo
- Publication number
- CA1229146A CA1229146A CA000470246A CA470246A CA1229146A CA 1229146 A CA1229146 A CA 1229146A CA 000470246 A CA000470246 A CA 000470246A CA 470246 A CA470246 A CA 470246A CA 1229146 A CA1229146 A CA 1229146A
- Authority
- CA
- Canada
- Prior art keywords
- temperature
- coolant
- engine
- radiator
- sensed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/02—Controlling of coolant flow the coolant being cooling-air
- F01P7/04—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio
- F01P7/044—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio using hydraulic drives
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/02—Controlling of coolant flow the coolant being cooling-air
- F01P7/04—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio
- F01P7/048—Controlling of coolant flow the coolant being cooling-air by varying pump speed, e.g. by changing pump-drive gear ratio using electrical drives
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/02—Controlling of coolant flow the coolant being cooling-air
- F01P7/10—Controlling of coolant flow the coolant being cooling-air by throttling amount of air flowing through liquid-to-air heat exchangers
- F01P7/12—Controlling of coolant flow the coolant being cooling-air by throttling amount of air flowing through liquid-to-air heat exchangers by thermostatic control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P7/00—Controlling of coolant flow
- F01P7/14—Controlling of coolant flow the coolant being liquid
- F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P2070/00—Details
- F01P2070/08—Using lubricant pressure as actuating fluid
Abstract
ENGINE TEMPERATURE CONTROL SYSTEM
ABSTRACT:
The operating temperature of an internal combustion engine is maintained within desired limits by employing a single coolant temperature sensor (10) for controlling and coordinating the operation of three different temperature control devices (45,46,47) for the engine coolant. When the sensed coolant temperature is in a relatively low range a flow control valve (45) controls the amount of coolant diverted from the engine jacket to a radiator (48) to dissipate heat absorbed by the coolant from the engine. If the coolant temperature exceeds that low range, even though the control valve (45) is fully open and all of the coolant is circulated through the radiator (48), the sensor (10) then effects the opening of radiator shutters (46) to cause ram air to impinge on the radiator (48) to increase the cooling of the coolant. If the temperature still continues to rise after the shutters (46) are fully open, the coolant sensor (10) causes operation of a variable speed fan drive (47) to blow a sufficient amount of air through the radiator (48) to cool the coolant back down to the desired operating range. Such sequential operation of the three control devices (45,46,47) provides close temperature control within a relatively narrow range despite wide variations of external conditions and load on the engine, resulting in higher efficiency and longer engine life.
ABSTRACT:
The operating temperature of an internal combustion engine is maintained within desired limits by employing a single coolant temperature sensor (10) for controlling and coordinating the operation of three different temperature control devices (45,46,47) for the engine coolant. When the sensed coolant temperature is in a relatively low range a flow control valve (45) controls the amount of coolant diverted from the engine jacket to a radiator (48) to dissipate heat absorbed by the coolant from the engine. If the coolant temperature exceeds that low range, even though the control valve (45) is fully open and all of the coolant is circulated through the radiator (48), the sensor (10) then effects the opening of radiator shutters (46) to cause ram air to impinge on the radiator (48) to increase the cooling of the coolant. If the temperature still continues to rise after the shutters (46) are fully open, the coolant sensor (10) causes operation of a variable speed fan drive (47) to blow a sufficient amount of air through the radiator (48) to cool the coolant back down to the desired operating range. Such sequential operation of the three control devices (45,46,47) provides close temperature control within a relatively narrow range despite wide variations of external conditions and load on the engine, resulting in higher efficiency and longer engine life.
Description
ENGINE TEMPERATURE CONTROL SYSTEM
Dew on This invention relates to a temperature control system, for an internal combustion engine, having several different temperature control devices rendered operable as needed to maintain the engine temperature at a preselected desired level in the presence of widely varying external and load conditions.
Internal combustion engines used in trucks may have three separate controls to keep the operating temperature constant at an optimum point. A thermostat or flow control valve is usually installed in the engine block to sense or monitor the temperature ox the coolant in the engine jacket, which coolant is circulated around the jacket by a coolant or water pump, and to divert a lo larger and larger amount of the coolant from the jacket to the truck's radiator to dissipate the engine heat as ; the coolant temperature rises through a relatively small temperature range At that time no appreciable air is ; passing through the radiator but the total volume of coolant available to absorb the heat from the engine has been increased. If the coolant temperature continues to increase even with the thermostat fully open and with all of the coolant being circulated through the radix atop, controllable radiator shutters will now become operable. These shutters are like Venetian blinds and are positioned in front of the radiator. They may be of the variable opening type or the on-off type and are normally closed so that no air can be drawn there through ~22~6 and to the radiator. A separate temperature sensor controls the operation of the radiator shutters and they will be opened by the sensor if the engine temperature exceeds the desired level after the thermostat is fully opened. With the shutters open, ram air is allowed to impinge on the radiator to effect cooling of the coolant circulating through the radiator and engine block. Ram air is the effective air that, due to the truck's velocity, strikes the radiator. Of course, if the truck is stationary there would be no ram air.
If the load on the engine or external conditions, such as the outside ambient temperature, causes the coolant temperature to continue rising even with the . .
thermostat and shutters fully open, a third temperature sensor will control the operation of a variable speed fan drive to pull outside air in through the shutters and then through the radiator to effect cooling of the coolant, the amount of air blown through the radiator, and hence the amount of heat dissipated, being proper-tonal to the fan speed. It is this third temperature control device that will be capable of providing as much cooling to the coolant as needed to keep the coolant temperature at the required level for optimum engine performance. Moreover, by setting the fan speed only as high as necessary to maintain the desired optimum engine temperature, energy will be conserved.
It is of utmost importance that the three temper-azure control devices function in the proper sequence.
For example, if the fan is operated before the shutters if the fan is operated before the shutters open a vacuum is created and the air flow becomes stalled, producing a very noisy condition. As another example, if the ~LZ29~ 6 thermostat fails to open but the shutters and fan are rendered operable, no coolant flows to the radiator - and the shutters and fan become ineffective. Unfortu-namely, in the past it has been extremely difficult to obtain the correct sequential operation of the thermos stat, shutters and fan drive. Since three separate sensors are needed, whenever one of the sensors drifts out of calibration the required operating sequence will be disrupted. Each of the sensors, and the act-atop that it controls, has a characteristic operating range and hysteresis which is extended further by reasonable manufacturing tolerances. In order for the control devices to work in the correct sequence, a rather wide total control range results. Engine temper-azure, allowed to vary over such a wide range, becomes dependent on such factors as load and ambient condo-lions. This wide temperature variation is not desirable due to its effects on engine efficiency and engine life.
The present invention constitutes an improvement over these prior engine temperature control systems by ensuring the proper sequential action of the coolant flow control valve, the radiator shutters and the variable speed fan drive. Moreover, the invention achieves a desirable reduction in the operating temper-azure range, namely closer temperature control to within narrow limits, resulting in higher efficiency and longer engine life.
The invention provides an engine temperature control system for maintaining the temperature of coolant, in the engine jacket of an internal combustion ....
Lo 6 engine, within desired narrow limits regardless of external conditions and load on the engine. The temper-azure control system comprises a radiator through which the coolant may be circulated from the engine jacket to effect cooling of the coolant. A temperature-sensor is provided for sensing the temperature of the coolant in the engine jacket, and there are means responsive to the temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature. A coolant flow control valve responds to the fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, to vary the amount of coolant diverted to and flowing through the radiator. Radiator shutters are controlled by the fluid pressure, when the sensed temperature is in a medium temperature range above the low temperature range, for adjusting the amount of ram air impinging on the radiator. Finally, the temperature control system includes a variable speed fan drive which responds to the fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium range, to blow a controlled amount of air through the radiator.
The features of the invention which are believed to be novel are set forth with particularity in the append dyed claims. The invention may best be understood, however, by reference to the following description in conjunction with the accompanying drawing in which:
FIGURE 1 schematically illustrates a temperature control system, for an internal combustion engine, constructed in accordance with one embodiment of the invention;
. , .
~9L22~
FIGURE 2 shows a characteristic curve that will be helpful in understanding the operation of the temper-azure control system; and, FIGURE 3 shows a portion of the temperature control 5 system of FIGURE 1 modified in accordance with another embodiment of the invention.
It will be assumed that the temperature control system shown in Figure 1 is incorporated in a truck engine, but it will be apparent that the invention can be employed with any internal combustion engine having several temperature control devices that are operated in sequence to maintain a desired engine operating temper-azure.
Temperature sensor 10 senses the temperature of the coolant in the engine jacket and may be located at any convenient point in the coolant flow path. Prefer-ably, the sensor is positioned where the coolant will be the hottest in the engine jacket, such as at the top of the engine block where the conventional thermostat is usually located. Sensor 10 comprises a thermistor having a positive temperature coefficient so that its resistance is directly proportional to the coolant temperature. Resistors 12, 13 and I in conjunction with the resistance of sensor 10 form a bridge circuit.
As the sensed coolant temperature changes, the voltage across circuit junctions or points 15 and 16 varies proportionally. Since sensor 10 has a positive temper-azure coefficient, when the coolant temperature in-creases, for example, the resistance of the sensor increases and the voltage at junction 16 increases relative to the fixed voltage at junction 15. Amplifier ...
I
18 amplifies the voltage difference between junctions 15 and 16 to produce on conductor 19 a voltage signal, which may be called a "temperature signal", having an amplitude directly proportional to the sensed coolant temperature. Resistors 21 and 22 control the amount of amplification.
A pulse width modulated signal is developed having a wave shape determined by the temperature signal on line 19. To explain, a pulse width modulated signal is rectangular shaped, containing periodically recurring positive-going pulse components with intervening Vega-tive-going pulse components. The frequency will be constant but the relative widths by the positive and negative pulse components will vary depending on the lo amplitude of the temperature signal. As the width or duration of each positive pulse component increases, each negative pulse component decreases proportionately, and vice versa. In other words, since the period or time duration of a complete cycle is constant, when the duration of a positive pulse component changes in one sense or direction the width of the immediately succeed-in negative pulse component must change in the opposite sense. The pulse width modulated signal has a duty cycle characteristic which is the ratio of the width of each positive-going pulse compared to the duration of a complete cycle The pulse width modulated signal is developed at the output of comparator 24. Amplifiers I and 27, and their associated circuit elements, form a well-known I
triangular wave generator or oscillator for supplying a triangular shaped voltage signal to the negative or inverting input of comparator 24, the positive or non-inverting input of which receives the temperature signal. Preferably, the frequency of the triangular shaped signal is approximately 10 hertz. The voltage at the negative input will vary alternately above and below the voltage level of the temperature voltage signal at the positive input. Each time the alternating voltage lo at the negative input drops below the temperature voltage at the positive input, the output voltage of comparator 24 abruptly switches from ground or zero volts to TV such as ~12 volts d-c, where it remains until the triangular shaped voltage signal at the negative input becomes greater than the temperature voltage signal at the positive input. At that instant, the output voltage of the comparator switches from its high level TV back to its low level or zero. The greater the amplitude of the temperature signal, the greater the time intervals during which the output of comparator 24 is established at its high potential level and the smaller the time intervals when the output is at zero potential. In this way, the output of comparator 24 provides a pulse width modulated, recta-galore shaped signal, the relative widths of the alter-noting positive-oing and negative-going pulses being modulated under the control of the temperature signal on line 19. The duty cycle of the pulse width modulated signal is the ratio of the time interval of one positive pulse component compared to a complete cycle, namely the total time duration of one positive pulse component and one negative pulse component. Hence, the duty cycle of the pulse width modulated signal at the output of comparator 24 will be directly proportional to the sensed coolant temperature.
Jo .
9~L6 The pulse width modulated signal operates the driver, comprising transistors 31 and 32, to effectively apply that signal to solenoid coil 33. The V+ operating potential at the right terminal of coil 33 may also be the ~12 volts. During each positive-going pulse when the output of comparator 24 is established at its high level, transistors 31 and 32 conduct and the left terminal of coil 33 will be essentially grounded, thereby applying a full 12 volts do across the coil.
During the intervening negative-going pulses, when the output of comparator 24 is zero, transistors 31 and 32 will be turned off and coil 33 will be de-energized.
Hence, coil 33 is alternately energized and downer-gibed, namely cycled on and off, and its duty cycle is the same as, and is determined by, the duty cycle of the pulse width modulated signal. Zoner diode 34 protects transistors 31 and 32 against inductive voltage spikes generated by coil 33 turning off.
Solenoid off-on valve 37 is controlled by solenoid coil 33, and since it is turned on and off at a rota-lively fast rate, the valve effectively provides a variable orifice or opening the size of which is deter-mined by the energization of coil 33~ Each time coil 33 is energized valve 37 is opened, and when the coil is de-energized the valve is closed. Thus, the greater the energization of coil 33, namely the greater the duty cycle, the less restriction introduced by valve 37 and the greater the effective opening or orifice.
Solenoid valve 37 is interposed in series with an oil circuit, the oil flowing from a pressurized oil ~x~g~
supply 39 through valve 37 and then through a fixed orifice 38 to an oil sup 41, from which the oil is returned over oil line 42 to the pressurized oil supply 39 which would include an oil pump Of course, in an internal combustion engine, especially a truck engine many sources of oil pressure are readily available. The engine oil pressure may be used, or pressurized oil may be obtained from the transmission supply. Moreover, and as will be made apparent, oil pressure is not essential.
Any source of pressurized fluid will suffice. For example, air pressure from air compressors, usually included in trucks, may be employed With the illustrated oil circuit, the oil pressure in oil line 43, which connects to the junction between valve 37 and fixed orifice 38, will constitute a con-trolled fluid (oil) pressure which is a junction of and represents the sensed coolant temperature. Specifically-lye the controlled oil pressure in line 43 is directly proportional to the sensed temperature. To explain further, if the coolant temperature is relatively low the duty cycle of solenoid valve 37 will likewise be relatively low and the effective opening of valve 37 will be relatively small. As a result, the restriction to the flow of oil through valve 37 will be relatively high causing the pressure drop across the valve to be relatively high, with most of the oil pressure drop from pressurized oil supply 39 to oil sup 41 being dropped across valve 37, rather than across fixed orifice 38. As the coolant temperature increases the duty cycle of coil 33 increases and the effective opening of valve 37 becomes Larger, thereby introducing less restriction to the oil flow and less pressure drop.
Consequently, as the coolant temperature rises the pressure drop decreases across valve 37 and increases ., .~.
29~L6 across fixed orifice 38, causing the oil pressure in oil line 43 to increase toward the oil supply pressure as the coolant temperature increases This oil pressure/
coolant temperature function is shown in Figure 2.
The controlled oil pressure in oil line 43 governs the operation of coolant flow control valve 45, radiator shutters 46 and variable speed fan drive 47, all three of which in turn control the temperature of the coolant in the radiator 48 of the internal combustion engine.
At very low coolant temperatures, such as when the engine it started or in extremely cold weather, the controlled oil pressure will be so low that none of the devices 45, 46 and 47 will be operated, and thus will be established in their normal positions. Specifically, flow control valve 45, which controls the amount of coolant diverted from the engine jacket and circulated through radiator 48, will be in its fully closed post-lion so that the coolant will be circulated by the coolant or water pump only around the engine jacket.
The radiator shutters 46 will be fully closed so no ram air impinges the radiator, and the fan drive 47 will be off so no air will be blown through the radiator. As the engine temperature and the coolant temperature increase, the controlled oil pressure in line 43 in-creases and flow control valve 45 opens in proportion tote temperature rise, allowing the coolant trapped in the engine jacket to flow through the radiator to dissipate the heat absorbed from the engine by the coolant. During this time the radiator shutters 46 and 0 fan drive 47 will be unaffected since they are con-strutted so they will not operate in response to the low oil pressure to which control valve 45 responds.
' ~Z2~
This operation at low temperatures is illustrated in Figure 2. If the coolant temperature increases to the extent that the increased oil pressure fully opens flow control valve 45, all of the coolant will be circulated through the radiator to be cooled. This occurs at the high temperature end of the low temper-azure range indicated by the legend "coolant flow operating range" in Figure 2. If at that time insuffi-client cooling occurs in the radiator, causing the engine temperature to continue rising, the radiator shutters begin to open. The pressure controlled act-atop for the radiator shutters is adjusted so that no movement thereof occurs until the oil pressure exceeds the level at which flow control valve 45 becomes fully opened. As the shutters open, in response to increasing oil pressure, more and more ram air is allowed to strike the radiator to dissipate heat Abe sorbed by the coolant. Depending on the vehicle's speed and ambient air temperature, the coolant may be cooled sufficiently to stabilize the engine temperature at the desired level required for optimum engine performance.
Assume now that external or load conditions prevent adequate cooling, even with the flow control valve 45 and the radiator shutters 46 fully open and the coolant becomes hotter. This point is indicated by the high temperature end of the medium temperature range, or "radiator shutters operating range" in Figure 2. At that point the oil pressure in line 43 will be suffix client Jo cause fan drive 47 to start rotating the fan to pull air through the radiator to effect additional .
I' .. .
., .
~;293L~6 cooling of the coolant. If the coolant temperature still keeps rising in the range indicated by the high temperature range or "fan drive operating range" in Figure I the increasing oil pressure causes the fan drive 47 to gradually increase the fan speed until the cooling effect on the coolant is sufficient to stabilize its temperature, and consequently the engine temper-azure, within the desired narrow limits for optimum engine performance.
The described engine temperature control arrange-mint of Figure 1 thus effects very close control of the engine operating temperature, maintaining it within a relatively narrow operating range even in the presence of widel~''varying external and toad conditions to achieve higher efficiency and longer engine life.
Moreover, hysteresis is substantially reduced and a much faster response to temperature change is obtained.
Figure 3 shows the manner in which the temperature control system of Figure 1 may be modified to provide a controlled oil pressure which is inversely proportion-at to the sensed temperature of the coolant. This is accomplished merely by reversing the order of solenoid valve 37 and fixed orifice 38 in the oil circuit.
Hence, the oil pressure/coolant temperature character-fistic curve will be a straight line as in Figure 2 bottle have an opposite polarity slope. At low coolant temperatures valve 37 introduces a high flow restriction and most of the pressure drop will be across that valve, the oil pressure at the junction of orifice 38 and valve 37 thereby being high. Conversely, at high coolant temperatures valve 37 presents a low flow restriction , ....
I
and most of the pressure drop will he across orifice 38.
Of course, the pressure actuated devices 45, 46 and 47 must be of the type that operate in a reverse manner as previously explained in connection with Figure 1. In other words, at low temperatures when the controlled oil pressure begins to drop from its maximum level as the coolant heats up, flow control valve 45 would begin to open. If the coolant temperature continues to increase into and through the medium temperature range, the oil pressure continues to drop and causes the radiator shutters to open. Assuming that the coolant temperature still keeps rising, the decreasing oil pressure occurring during the high temperature range causes the fan speed to gradually increase until the necessary amount of air is pulled through the radiator to properly cool the coolant. An advantage of the Figure 3 embodiment is that since the lower the oil pressure the greater the cooling imparted to the cool-ant, if there is a failure in the oil supply or valve opening maximum cooling of thy coolant will occur.
; The flow control valve 45 and the radiator shutters 46 will become fully opened and the fan will be driven by fan drive 47 at its maximum speed. This is a safety feature to prevent engine overheating in the event of a breakdown in the source of pressurized fluid or valve operation.
While particular embodiments of the invention have been shown and described, modifications may be made, and it is intended in the appended claims to cover all such modifications as may fall within the true spirit and scope of the invention.
.
Dew on This invention relates to a temperature control system, for an internal combustion engine, having several different temperature control devices rendered operable as needed to maintain the engine temperature at a preselected desired level in the presence of widely varying external and load conditions.
Internal combustion engines used in trucks may have three separate controls to keep the operating temperature constant at an optimum point. A thermostat or flow control valve is usually installed in the engine block to sense or monitor the temperature ox the coolant in the engine jacket, which coolant is circulated around the jacket by a coolant or water pump, and to divert a lo larger and larger amount of the coolant from the jacket to the truck's radiator to dissipate the engine heat as ; the coolant temperature rises through a relatively small temperature range At that time no appreciable air is ; passing through the radiator but the total volume of coolant available to absorb the heat from the engine has been increased. If the coolant temperature continues to increase even with the thermostat fully open and with all of the coolant being circulated through the radix atop, controllable radiator shutters will now become operable. These shutters are like Venetian blinds and are positioned in front of the radiator. They may be of the variable opening type or the on-off type and are normally closed so that no air can be drawn there through ~22~6 and to the radiator. A separate temperature sensor controls the operation of the radiator shutters and they will be opened by the sensor if the engine temperature exceeds the desired level after the thermostat is fully opened. With the shutters open, ram air is allowed to impinge on the radiator to effect cooling of the coolant circulating through the radiator and engine block. Ram air is the effective air that, due to the truck's velocity, strikes the radiator. Of course, if the truck is stationary there would be no ram air.
If the load on the engine or external conditions, such as the outside ambient temperature, causes the coolant temperature to continue rising even with the . .
thermostat and shutters fully open, a third temperature sensor will control the operation of a variable speed fan drive to pull outside air in through the shutters and then through the radiator to effect cooling of the coolant, the amount of air blown through the radiator, and hence the amount of heat dissipated, being proper-tonal to the fan speed. It is this third temperature control device that will be capable of providing as much cooling to the coolant as needed to keep the coolant temperature at the required level for optimum engine performance. Moreover, by setting the fan speed only as high as necessary to maintain the desired optimum engine temperature, energy will be conserved.
It is of utmost importance that the three temper-azure control devices function in the proper sequence.
For example, if the fan is operated before the shutters if the fan is operated before the shutters open a vacuum is created and the air flow becomes stalled, producing a very noisy condition. As another example, if the ~LZ29~ 6 thermostat fails to open but the shutters and fan are rendered operable, no coolant flows to the radiator - and the shutters and fan become ineffective. Unfortu-namely, in the past it has been extremely difficult to obtain the correct sequential operation of the thermos stat, shutters and fan drive. Since three separate sensors are needed, whenever one of the sensors drifts out of calibration the required operating sequence will be disrupted. Each of the sensors, and the act-atop that it controls, has a characteristic operating range and hysteresis which is extended further by reasonable manufacturing tolerances. In order for the control devices to work in the correct sequence, a rather wide total control range results. Engine temper-azure, allowed to vary over such a wide range, becomes dependent on such factors as load and ambient condo-lions. This wide temperature variation is not desirable due to its effects on engine efficiency and engine life.
The present invention constitutes an improvement over these prior engine temperature control systems by ensuring the proper sequential action of the coolant flow control valve, the radiator shutters and the variable speed fan drive. Moreover, the invention achieves a desirable reduction in the operating temper-azure range, namely closer temperature control to within narrow limits, resulting in higher efficiency and longer engine life.
The invention provides an engine temperature control system for maintaining the temperature of coolant, in the engine jacket of an internal combustion ....
Lo 6 engine, within desired narrow limits regardless of external conditions and load on the engine. The temper-azure control system comprises a radiator through which the coolant may be circulated from the engine jacket to effect cooling of the coolant. A temperature-sensor is provided for sensing the temperature of the coolant in the engine jacket, and there are means responsive to the temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature. A coolant flow control valve responds to the fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, to vary the amount of coolant diverted to and flowing through the radiator. Radiator shutters are controlled by the fluid pressure, when the sensed temperature is in a medium temperature range above the low temperature range, for adjusting the amount of ram air impinging on the radiator. Finally, the temperature control system includes a variable speed fan drive which responds to the fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium range, to blow a controlled amount of air through the radiator.
The features of the invention which are believed to be novel are set forth with particularity in the append dyed claims. The invention may best be understood, however, by reference to the following description in conjunction with the accompanying drawing in which:
FIGURE 1 schematically illustrates a temperature control system, for an internal combustion engine, constructed in accordance with one embodiment of the invention;
. , .
~9L22~
FIGURE 2 shows a characteristic curve that will be helpful in understanding the operation of the temper-azure control system; and, FIGURE 3 shows a portion of the temperature control 5 system of FIGURE 1 modified in accordance with another embodiment of the invention.
It will be assumed that the temperature control system shown in Figure 1 is incorporated in a truck engine, but it will be apparent that the invention can be employed with any internal combustion engine having several temperature control devices that are operated in sequence to maintain a desired engine operating temper-azure.
Temperature sensor 10 senses the temperature of the coolant in the engine jacket and may be located at any convenient point in the coolant flow path. Prefer-ably, the sensor is positioned where the coolant will be the hottest in the engine jacket, such as at the top of the engine block where the conventional thermostat is usually located. Sensor 10 comprises a thermistor having a positive temperature coefficient so that its resistance is directly proportional to the coolant temperature. Resistors 12, 13 and I in conjunction with the resistance of sensor 10 form a bridge circuit.
As the sensed coolant temperature changes, the voltage across circuit junctions or points 15 and 16 varies proportionally. Since sensor 10 has a positive temper-azure coefficient, when the coolant temperature in-creases, for example, the resistance of the sensor increases and the voltage at junction 16 increases relative to the fixed voltage at junction 15. Amplifier ...
I
18 amplifies the voltage difference between junctions 15 and 16 to produce on conductor 19 a voltage signal, which may be called a "temperature signal", having an amplitude directly proportional to the sensed coolant temperature. Resistors 21 and 22 control the amount of amplification.
A pulse width modulated signal is developed having a wave shape determined by the temperature signal on line 19. To explain, a pulse width modulated signal is rectangular shaped, containing periodically recurring positive-going pulse components with intervening Vega-tive-going pulse components. The frequency will be constant but the relative widths by the positive and negative pulse components will vary depending on the lo amplitude of the temperature signal. As the width or duration of each positive pulse component increases, each negative pulse component decreases proportionately, and vice versa. In other words, since the period or time duration of a complete cycle is constant, when the duration of a positive pulse component changes in one sense or direction the width of the immediately succeed-in negative pulse component must change in the opposite sense. The pulse width modulated signal has a duty cycle characteristic which is the ratio of the width of each positive-going pulse compared to the duration of a complete cycle The pulse width modulated signal is developed at the output of comparator 24. Amplifiers I and 27, and their associated circuit elements, form a well-known I
triangular wave generator or oscillator for supplying a triangular shaped voltage signal to the negative or inverting input of comparator 24, the positive or non-inverting input of which receives the temperature signal. Preferably, the frequency of the triangular shaped signal is approximately 10 hertz. The voltage at the negative input will vary alternately above and below the voltage level of the temperature voltage signal at the positive input. Each time the alternating voltage lo at the negative input drops below the temperature voltage at the positive input, the output voltage of comparator 24 abruptly switches from ground or zero volts to TV such as ~12 volts d-c, where it remains until the triangular shaped voltage signal at the negative input becomes greater than the temperature voltage signal at the positive input. At that instant, the output voltage of the comparator switches from its high level TV back to its low level or zero. The greater the amplitude of the temperature signal, the greater the time intervals during which the output of comparator 24 is established at its high potential level and the smaller the time intervals when the output is at zero potential. In this way, the output of comparator 24 provides a pulse width modulated, recta-galore shaped signal, the relative widths of the alter-noting positive-oing and negative-going pulses being modulated under the control of the temperature signal on line 19. The duty cycle of the pulse width modulated signal is the ratio of the time interval of one positive pulse component compared to a complete cycle, namely the total time duration of one positive pulse component and one negative pulse component. Hence, the duty cycle of the pulse width modulated signal at the output of comparator 24 will be directly proportional to the sensed coolant temperature.
Jo .
9~L6 The pulse width modulated signal operates the driver, comprising transistors 31 and 32, to effectively apply that signal to solenoid coil 33. The V+ operating potential at the right terminal of coil 33 may also be the ~12 volts. During each positive-going pulse when the output of comparator 24 is established at its high level, transistors 31 and 32 conduct and the left terminal of coil 33 will be essentially grounded, thereby applying a full 12 volts do across the coil.
During the intervening negative-going pulses, when the output of comparator 24 is zero, transistors 31 and 32 will be turned off and coil 33 will be de-energized.
Hence, coil 33 is alternately energized and downer-gibed, namely cycled on and off, and its duty cycle is the same as, and is determined by, the duty cycle of the pulse width modulated signal. Zoner diode 34 protects transistors 31 and 32 against inductive voltage spikes generated by coil 33 turning off.
Solenoid off-on valve 37 is controlled by solenoid coil 33, and since it is turned on and off at a rota-lively fast rate, the valve effectively provides a variable orifice or opening the size of which is deter-mined by the energization of coil 33~ Each time coil 33 is energized valve 37 is opened, and when the coil is de-energized the valve is closed. Thus, the greater the energization of coil 33, namely the greater the duty cycle, the less restriction introduced by valve 37 and the greater the effective opening or orifice.
Solenoid valve 37 is interposed in series with an oil circuit, the oil flowing from a pressurized oil ~x~g~
supply 39 through valve 37 and then through a fixed orifice 38 to an oil sup 41, from which the oil is returned over oil line 42 to the pressurized oil supply 39 which would include an oil pump Of course, in an internal combustion engine, especially a truck engine many sources of oil pressure are readily available. The engine oil pressure may be used, or pressurized oil may be obtained from the transmission supply. Moreover, and as will be made apparent, oil pressure is not essential.
Any source of pressurized fluid will suffice. For example, air pressure from air compressors, usually included in trucks, may be employed With the illustrated oil circuit, the oil pressure in oil line 43, which connects to the junction between valve 37 and fixed orifice 38, will constitute a con-trolled fluid (oil) pressure which is a junction of and represents the sensed coolant temperature. Specifically-lye the controlled oil pressure in line 43 is directly proportional to the sensed temperature. To explain further, if the coolant temperature is relatively low the duty cycle of solenoid valve 37 will likewise be relatively low and the effective opening of valve 37 will be relatively small. As a result, the restriction to the flow of oil through valve 37 will be relatively high causing the pressure drop across the valve to be relatively high, with most of the oil pressure drop from pressurized oil supply 39 to oil sup 41 being dropped across valve 37, rather than across fixed orifice 38. As the coolant temperature increases the duty cycle of coil 33 increases and the effective opening of valve 37 becomes Larger, thereby introducing less restriction to the oil flow and less pressure drop.
Consequently, as the coolant temperature rises the pressure drop decreases across valve 37 and increases ., .~.
29~L6 across fixed orifice 38, causing the oil pressure in oil line 43 to increase toward the oil supply pressure as the coolant temperature increases This oil pressure/
coolant temperature function is shown in Figure 2.
The controlled oil pressure in oil line 43 governs the operation of coolant flow control valve 45, radiator shutters 46 and variable speed fan drive 47, all three of which in turn control the temperature of the coolant in the radiator 48 of the internal combustion engine.
At very low coolant temperatures, such as when the engine it started or in extremely cold weather, the controlled oil pressure will be so low that none of the devices 45, 46 and 47 will be operated, and thus will be established in their normal positions. Specifically, flow control valve 45, which controls the amount of coolant diverted from the engine jacket and circulated through radiator 48, will be in its fully closed post-lion so that the coolant will be circulated by the coolant or water pump only around the engine jacket.
The radiator shutters 46 will be fully closed so no ram air impinges the radiator, and the fan drive 47 will be off so no air will be blown through the radiator. As the engine temperature and the coolant temperature increase, the controlled oil pressure in line 43 in-creases and flow control valve 45 opens in proportion tote temperature rise, allowing the coolant trapped in the engine jacket to flow through the radiator to dissipate the heat absorbed from the engine by the coolant. During this time the radiator shutters 46 and 0 fan drive 47 will be unaffected since they are con-strutted so they will not operate in response to the low oil pressure to which control valve 45 responds.
' ~Z2~
This operation at low temperatures is illustrated in Figure 2. If the coolant temperature increases to the extent that the increased oil pressure fully opens flow control valve 45, all of the coolant will be circulated through the radiator to be cooled. This occurs at the high temperature end of the low temper-azure range indicated by the legend "coolant flow operating range" in Figure 2. If at that time insuffi-client cooling occurs in the radiator, causing the engine temperature to continue rising, the radiator shutters begin to open. The pressure controlled act-atop for the radiator shutters is adjusted so that no movement thereof occurs until the oil pressure exceeds the level at which flow control valve 45 becomes fully opened. As the shutters open, in response to increasing oil pressure, more and more ram air is allowed to strike the radiator to dissipate heat Abe sorbed by the coolant. Depending on the vehicle's speed and ambient air temperature, the coolant may be cooled sufficiently to stabilize the engine temperature at the desired level required for optimum engine performance.
Assume now that external or load conditions prevent adequate cooling, even with the flow control valve 45 and the radiator shutters 46 fully open and the coolant becomes hotter. This point is indicated by the high temperature end of the medium temperature range, or "radiator shutters operating range" in Figure 2. At that point the oil pressure in line 43 will be suffix client Jo cause fan drive 47 to start rotating the fan to pull air through the radiator to effect additional .
I' .. .
., .
~;293L~6 cooling of the coolant. If the coolant temperature still keeps rising in the range indicated by the high temperature range or "fan drive operating range" in Figure I the increasing oil pressure causes the fan drive 47 to gradually increase the fan speed until the cooling effect on the coolant is sufficient to stabilize its temperature, and consequently the engine temper-azure, within the desired narrow limits for optimum engine performance.
The described engine temperature control arrange-mint of Figure 1 thus effects very close control of the engine operating temperature, maintaining it within a relatively narrow operating range even in the presence of widel~''varying external and toad conditions to achieve higher efficiency and longer engine life.
Moreover, hysteresis is substantially reduced and a much faster response to temperature change is obtained.
Figure 3 shows the manner in which the temperature control system of Figure 1 may be modified to provide a controlled oil pressure which is inversely proportion-at to the sensed temperature of the coolant. This is accomplished merely by reversing the order of solenoid valve 37 and fixed orifice 38 in the oil circuit.
Hence, the oil pressure/coolant temperature character-fistic curve will be a straight line as in Figure 2 bottle have an opposite polarity slope. At low coolant temperatures valve 37 introduces a high flow restriction and most of the pressure drop will be across that valve, the oil pressure at the junction of orifice 38 and valve 37 thereby being high. Conversely, at high coolant temperatures valve 37 presents a low flow restriction , ....
I
and most of the pressure drop will he across orifice 38.
Of course, the pressure actuated devices 45, 46 and 47 must be of the type that operate in a reverse manner as previously explained in connection with Figure 1. In other words, at low temperatures when the controlled oil pressure begins to drop from its maximum level as the coolant heats up, flow control valve 45 would begin to open. If the coolant temperature continues to increase into and through the medium temperature range, the oil pressure continues to drop and causes the radiator shutters to open. Assuming that the coolant temperature still keeps rising, the decreasing oil pressure occurring during the high temperature range causes the fan speed to gradually increase until the necessary amount of air is pulled through the radiator to properly cool the coolant. An advantage of the Figure 3 embodiment is that since the lower the oil pressure the greater the cooling imparted to the cool-ant, if there is a failure in the oil supply or valve opening maximum cooling of thy coolant will occur.
; The flow control valve 45 and the radiator shutters 46 will become fully opened and the fan will be driven by fan drive 47 at its maximum speed. This is a safety feature to prevent engine overheating in the event of a breakdown in the source of pressurized fluid or valve operation.
While particular embodiments of the invention have been shown and described, modifications may be made, and it is intended in the appended claims to cover all such modifications as may fall within the true spirit and scope of the invention.
.
Claims (11)
1. An engine temperature control system for maintaining the temperature of coolant, in the engine jacket of an internal combustion engine, within desired narrow limits regardless of external conditions and load on the engine, comprising:
a radiator through which the coolant may be circulated from the engine jacket to effect cooling of the coolant;
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature;
a coolant flow control valve which responds to the fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, to vary the amount of coolant diverted to and flowing through the radiator;
radiator shutters controlled by the fluid pressure, when the sensed temperature is in a medium temperature range above the low temperature range, for adjusting the amount of ram air impinging on the radi-ator;
and a variable speed fan drive responsive to the fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium range, for blowing a controlled amount of air through the radiator.
a radiator through which the coolant may be circulated from the engine jacket to effect cooling of the coolant;
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature;
a coolant flow control valve which responds to the fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, to vary the amount of coolant diverted to and flowing through the radiator;
radiator shutters controlled by the fluid pressure, when the sensed temperature is in a medium temperature range above the low temperature range, for adjusting the amount of ram air impinging on the radi-ator;
and a variable speed fan drive responsive to the fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium range, for blowing a controlled amount of air through the radiator.
2. An engine temperature control system according to Claim 1 wherein the controlled fluid pressure is directly proportional to the sensed temperature of the coolant.
3. An engine temperature control system according to Claim 1 wherein the controlled fluid pressure is inversely proportional to the sensed temperature of the coolant.
4. An engine temperature control system according to Claim 1 and including a pulse width modulation circuit for producing, in response to said temperature sensor, a pulse width modulated signal having a duty cycle which is proportional to the sensed coolant temperature, the pulse width modulated signal being utilized to provide the controlled fluid pressure.
5. An engine temperature control system according to Claim 4 and including means responsive to said temperature sensor for providing a temperature signal having an amplitude proportional to the sensed temper-ature, and wherein said pulse width modulated signal is developed in response to the temperature signal.
6. An engine temperature control system according to Claim 5 wherein said temperature signal is applied to a comparator which also receives a triangular shaped signal, said pulse width modulated signal being produced at the output of said comparator.
7. An engine temperature control system according to Claim 4 wherein the controlled fluid pressure is proportional to the duty cycle of said pulse width modulated signal and is produced by supplying pres-surized fluid to a solenoid off-on valve operated by the pulse width modulated signal, the effective opening of the solenoid valve and the pressure drop thereacross being proportional to the duty cycle of the pulse width modulated signal.
8. An engine temperature control system according to Claim 7 wherein the pressurized fluid is pressurized oil which flows through an oil circuit from a pres-surized oil supply through said solenoid off-on valve and then through a fixed orifice and finally back to the oil supply, the controlled fluid pressure being directly proportional to the sensed temperature of the coolant and being developed at the junction in the oil circuit between the output of the solenoid valve and the input to the fixed orifice.
9. An engine temperature control system according to Claim 7 wherein the pressurized fluid is pressurized oil which flows through an oil circuit from a pres-surized oil supply through a fixed orifice and then through said solenoid off-on valve and finally back to the oil supply, the controlled fluid pressure being inversely proportional to the sensed temperature of the coolant and being developed at the junction in the oil circuit between the output of the fixed orifice and the input to the solenoid valve.
10. An engine temperature control system for maintaining the temperature of coolant, in the engine jacket of an internal combustion engine, within desired narrow limits despite wide variations of external conditions and load on the engine, where a flow control valve controls the coolant flow from the engine jacket to a radiator having controllable shutters for varying the amount of ram air striking the radiator, and where a variable speed fan drive controls the amount of air blown through the radiator, said engine temperature control system comprising:
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature;
and means, responsive to the fluid pressure, for sequentially operating the flow control valve, radiator shutters and variable speed fan drive as the sensed coolant temperature rises through predetermined low, medium and high temperature ranges, the flow control valve increasing the amount of coolant circulating through the radiator as the sensed temperature increases in the low temperature range, the radiator shutters increasing the amount of ram air impinging on the radiator as the sensed temper-ature increases in the medium temperature range, and the fan drive increasing the amount of air pulled through the radiator as the temperature increases in the high temperature range.
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a controlled fluid pressure which is a function of and represents the sensed temperature;
and means, responsive to the fluid pressure, for sequentially operating the flow control valve, radiator shutters and variable speed fan drive as the sensed coolant temperature rises through predetermined low, medium and high temperature ranges, the flow control valve increasing the amount of coolant circulating through the radiator as the sensed temperature increases in the low temperature range, the radiator shutters increasing the amount of ram air impinging on the radiator as the sensed temper-ature increases in the medium temperature range, and the fan drive increasing the amount of air pulled through the radiator as the temperature increases in the high temperature range.
11. An engine temperature control system for controlling the temperature of coolant in the engine jacket of an internal combustion engine, where the coolant may be circulated, via a flow control valve, around the engine jacket and through a radiator having controllable shutters for varying the amount of ram air that may impinge on the radiator, a variable speed fan drive being provided to control the amount of air blown through the radiator, said engine temperature control system comprising:
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a pulse width modulated signal having a duty cycle which is proportional to the sensed temper-ature;
a source of pressurized fluid;
means, coupled to said source of pressurized fluid and responsive to said pulse width modulated signal, for producing a controlled fluid pressure which is proportional to the sensed temperature;
means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, for controlling the position of the coolant flow control valve to vary the amount of coolant diverted to and flowing through the radiator, the flow control valve being fully open to circulate all of the coolant through the radiator when the sensed coolant temperature is at the high end of the low temperature range;
means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a medium temperature range above the low temperature range, for adjusting the position of the radiator shutters to vary the amount of ram air striking the radiator, the shutters being fully open to maximize the amount of ram air when the sensed coolant temperature is at the high end of the medium temperature range;
and means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium temperature range, for varying the speed of the fan drive to control the amount of air pulled through the radiator, thereby to maintain the coolant temperature within desired narrow temperature limits regardless of external conditions and load on the engine.
a temperature sensor for sensing the temper-ature of the coolant in the engine jacket;
means responsive to said temperature sensor for producing a pulse width modulated signal having a duty cycle which is proportional to the sensed temper-ature;
a source of pressurized fluid;
means, coupled to said source of pressurized fluid and responsive to said pulse width modulated signal, for producing a controlled fluid pressure which is proportional to the sensed temperature;
means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively low temperature range, for controlling the position of the coolant flow control valve to vary the amount of coolant diverted to and flowing through the radiator, the flow control valve being fully open to circulate all of the coolant through the radiator when the sensed coolant temperature is at the high end of the low temperature range;
means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a medium temperature range above the low temperature range, for adjusting the position of the radiator shutters to vary the amount of ram air striking the radiator, the shutters being fully open to maximize the amount of ram air when the sensed coolant temperature is at the high end of the medium temperature range;
and means for utilizing said controlled fluid pressure, when the sensed coolant temperature is in a relatively high temperature range above the medium temperature range, for varying the speed of the fan drive to control the amount of air pulled through the radiator, thereby to maintain the coolant temperature within desired narrow temperature limits regardless of external conditions and load on the engine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US573,188 | 1984-01-23 | ||
| US06/573,188 US4489680A (en) | 1984-01-23 | 1984-01-23 | Engine temperature control system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1229146A true CA1229146A (en) | 1987-11-10 |
Family
ID=24290986
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000470246A Expired CA1229146A (en) | 1984-01-23 | 1984-12-14 | Engine temperature control system |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4489680A (en) |
| EP (1) | EP0154090B1 (en) |
| JP (1) | JPS60159325A (en) |
| CA (1) | CA1229146A (en) |
| DE (1) | DE3468723D1 (en) |
Families Citing this family (47)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4539943A (en) * | 1983-09-20 | 1985-09-10 | Aisin Seiki Kabushiki Kaisha | Engine cooling system |
| US4616599A (en) * | 1984-02-09 | 1986-10-14 | Mazda Motor Corporation | Cooling arrangement for water-cooled internal combustion engine |
| US4708095A (en) * | 1986-06-16 | 1987-11-24 | Deere & Company | Combined engine cooling and lube system |
| DE3625375A1 (en) * | 1986-07-26 | 1988-02-04 | Porsche Ag | COOLING FLAP AND BLOWER CONTROL FOR MOTOR VEHICLES |
| US4875521A (en) * | 1987-02-27 | 1989-10-24 | Roger Clemente | Electric fan assembly for over-the-road trucks |
| DE3714842A1 (en) * | 1987-05-05 | 1988-11-17 | Sueddeutsche Kuehler Behr | FAN DRIVE FOR A COOLING SYSTEM, ESPECIALLY FOR RAIL VEHICLES |
| US5457766A (en) * | 1992-05-23 | 1995-10-10 | Samsung Electronics Co., Ltd. | Fan speed control circuit |
| US5216983A (en) * | 1992-10-26 | 1993-06-08 | Harvard Industries, Inc. | Vehicle hydraulic cooling fan system |
| JPH07259562A (en) * | 1994-03-23 | 1995-10-09 | Unisia Jecs Corp | Diagnostic device of radiator fan controller |
| US5669335A (en) * | 1994-09-14 | 1997-09-23 | Thomas J. Hollis | System for controlling the state of a flow control valve |
| US5657722A (en) * | 1996-01-30 | 1997-08-19 | Thomas J. Hollis | System for maintaining engine oil at a desired temperature |
| US5507251A (en) * | 1995-06-06 | 1996-04-16 | Hollis; Thomas J. | System for determining the load condition of an engine for maintaining optimum engine oil temperature |
| US5947247A (en) * | 1995-09-18 | 1999-09-07 | Rockford Powertrain, Inc. | Continuously variable fan drive clutch |
| US5855266A (en) * | 1995-09-18 | 1999-01-05 | Rockford Powertrain, Inc. | Fan clutch for vehicles configured for low engine speed |
| US5937979A (en) * | 1995-09-18 | 1999-08-17 | Rockford Powertrain, Inc. | Continuosly variable fan drive clutch |
| US5660149A (en) * | 1995-12-21 | 1997-08-26 | Siemens Electric Limited | Total cooling assembly for I.C. engine-powered vehicles |
| DE69735940T2 (en) * | 1996-05-16 | 2006-12-21 | NGK Spark Plug Co., Ltd., Nagoya | detonator |
| US5960748A (en) | 1997-05-02 | 1999-10-05 | Valeo, Inc. | Vehicle hydraulic component support and cooling system |
| US6178928B1 (en) | 1998-06-17 | 2001-01-30 | Siemens Canada Limited | Internal combustion engine total cooling control system |
| US6030314A (en) * | 1998-09-28 | 2000-02-29 | Caterpillar Inc. | Method and apparatus for retarding a work machine having a fluid-cooled brake system |
| JP2000161063A (en) * | 1998-11-26 | 2000-06-13 | Nippon Thermostat Kk | Cooling controller for internal combustion engine |
| US6463891B2 (en) | 1999-12-17 | 2002-10-15 | Caterpillar Inc. | Twin fan control system and method |
| FR2804720B1 (en) * | 2000-02-03 | 2002-06-21 | Peugeot Citroen Automobiles Sa | COOLING DEVICE OF A MOTOR VEHICLE ENGINE |
| FR2806444B1 (en) * | 2000-03-17 | 2002-06-07 | Peugeot Citroen Automobiles Sa | COOLING DEVICE OF A MOTOR VEHICLE ENGINE |
| DE10058374B4 (en) * | 2000-11-24 | 2011-09-15 | Robert Seuffer Gmbh & Co. Kg | Device for regulating the temperature of an internal combustion engine |
| US20060211364A1 (en) * | 2001-08-01 | 2006-09-21 | Friedrich Brotz | Cooling system for motor vehicles and method for controlling at least one air mass flow through a radiator |
| US6695047B2 (en) * | 2002-01-28 | 2004-02-24 | Jon P. Brocksopp | Modular temperature control system |
| DE10224063A1 (en) * | 2002-05-31 | 2003-12-11 | Daimler Chrysler Ag | Method for heat regulation of an internal combustion engine for vehicles |
| US20040244759A1 (en) * | 2003-06-06 | 2004-12-09 | Britt Robert Lee | Electric oil pump |
| US7165514B2 (en) * | 2004-10-06 | 2007-01-23 | Deere & Company | Variable speed fan drive |
| US7506537B2 (en) * | 2006-09-01 | 2009-03-24 | Wisconsin Alumni Research Foundation | Internal combustion engine testing with thermal simulation of additional cylinders |
| DE102008055632B4 (en) * | 2008-11-03 | 2012-05-16 | Aerodyn Engineering Gmbh | Method for lubricating a gearbox |
| CN102481137B (en) | 2009-06-30 | 2015-03-18 | 皇家飞利浦电子股份有限公司 | Supersonic device and method for shear wave dispersion vibrometry |
| US20110089911A1 (en) * | 2009-10-05 | 2011-04-21 | Jean-Marie Loisel | Integrated generator field flash |
| US20120097464A1 (en) * | 2010-10-22 | 2012-04-26 | Gm Global Technology Operations, Inc. | Control of a shutter via bi-directional communication using a single wire |
| US9121335B2 (en) * | 2011-05-13 | 2015-09-01 | Ford Global Technologies, Llc | System and method for an engine comprising a liquid cooling system and oil supply |
| US9175601B2 (en) | 2012-01-04 | 2015-11-03 | Ini Power Systems, Inc. | Flex fuel field generator |
| US9188033B2 (en) * | 2012-01-04 | 2015-11-17 | Ini Power Systems, Inc. | Flexible fuel generator and methods of use thereof |
| US8810053B2 (en) | 2012-02-29 | 2014-08-19 | Ini Power Systems, Inc. | Method and apparatus for efficient fuel consumption |
| JP5880229B2 (en) * | 2012-04-06 | 2016-03-08 | アイシン精機株式会社 | Grill shutter device |
| USD733052S1 (en) | 2012-12-20 | 2015-06-30 | Ini Power Systems, Inc. | Flexible fuel generator |
| US9828932B2 (en) * | 2013-03-08 | 2017-11-28 | GM Global Technology Operations LLC | System and method for controlling a cooling system of an engine equipped with a start-stop system |
| US9523306B2 (en) * | 2014-05-13 | 2016-12-20 | International Engine Intellectual Property Company, Llc. | Engine cooling fan control strategy |
| US9909534B2 (en) | 2014-09-22 | 2018-03-06 | Ini Power Systems, Inc. | Carbureted engine having an adjustable fuel to air ratio |
| USD827572S1 (en) | 2015-03-31 | 2018-09-04 | Ini Power Systems, Inc. | Flexible fuel generator |
| US10030609B2 (en) | 2015-11-05 | 2018-07-24 | Ini Power Systems, Inc. | Thermal choke, autostart generator system, and method of use thereof |
| US11512623B2 (en) | 2017-07-17 | 2022-11-29 | Kohler Co. | Apparatus for controlling cooling airflow to an intenral combustion engine, and engines and methods utilizing the same |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2189888A (en) * | 1938-02-07 | 1940-02-13 | Fairbanks Morse & Co | Thermal control of internal combustion engines |
| US2291283A (en) * | 1939-02-28 | 1942-07-28 | Us Gauge Co | Automatic control system |
| US3854459A (en) * | 1973-12-28 | 1974-12-17 | Mack Trucks | Fan shroud for an engine cooling system |
| US4112703A (en) * | 1976-12-27 | 1978-09-12 | Borg-Warner Corporation | Refrigeration control system |
| US4228880A (en) * | 1978-09-25 | 1980-10-21 | Eaton Corporation | Pulse control of an electro magnetically actuated viscous fluid coupling |
| DE2938706A1 (en) * | 1979-09-25 | 1981-04-09 | Klöckner-Humboldt-Deutz AG, 5000 Köln | FILLING CONTROL FOR A HYDRODYNAMIC CLUTCH |
| JPS58124017A (en) * | 1982-01-19 | 1983-07-23 | Nippon Denso Co Ltd | Cooling system controller of engine |
-
1984
- 1984-01-23 US US06/573,188 patent/US4489680A/en not_active Expired - Fee Related
- 1984-12-12 DE DE8484308625T patent/DE3468723D1/en not_active Expired
- 1984-12-12 EP EP84308625A patent/EP0154090B1/en not_active Expired
- 1984-12-14 CA CA000470246A patent/CA1229146A/en not_active Expired
- 1984-12-24 JP JP59272709A patent/JPS60159325A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0154090A1 (en) | 1985-09-11 |
| DE3468723D1 (en) | 1988-02-18 |
| EP0154090B1 (en) | 1988-01-13 |
| US4489680A (en) | 1984-12-25 |
| JPS60159325A (en) | 1985-08-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1229146A (en) | Engine temperature control system | |
| US4555910A (en) | Coolant/refrigerant temperature control system | |
| CA1230397A (en) | Temperature control system for internal combustion engine | |
| CA1088184A (en) | Electronic speed control for a variable speed fan drive | |
| JP2662187B2 (en) | Cooling system for an internal combustion engine of a vehicle, comprising a thermostat valve having an electrically heatable expansion material element | |
| US4112703A (en) | Refrigeration control system | |
| US6329777B1 (en) | Motor drive control apparatus and method having motor current limit function upon motor lock | |
| US5127576A (en) | Vehicle passenger compartment temperature control system with P.I.D. control of heater servo-valve | |
| US5165377A (en) | Hydraulic fan drive system | |
| US4590892A (en) | Cooling system for vehicle | |
| GB1587111A (en) | Temperature control system for refrigeration system | |
| US4378760A (en) | Device for controlling the ventilating means of an internal combustion engine | |
| IE49153B1 (en) | Vapor compression refrigeration system and a method of operation therefor | |
| GB2190807A (en) | Method of ventilation or heat transfer | |
| JPS5839083B2 (en) | Automotive air conditioner | |
| US5216895A (en) | Engine idle speed control system for automotive vehicle | |
| US4364444A (en) | Temperature regulation system for electric vehicles | |
| US4201061A (en) | Automatic chilled water setpoint temperature control | |
| US3477240A (en) | Refrigerating method and system for maintaining substantially constant temperature | |
| US2505597A (en) | Temperature regulating system | |
| JPS61116255A (en) | Method and device for controlling flow rate of refrigerant | |
| KR0183071B1 (en) | Clutch fan | |
| US4573559A (en) | Subway electric motor and fan construction | |
| KR0122055Y1 (en) | Cooling system for auto-transmission | |
| JPH0214967B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |