DE3540780A1 - Injection device for injection motors - Google Patents

Abstract

The injection device has a first needle valve (16) and a second needle valve (38), which are both controlled by the pressure of the ignition fuel. In addition an interrupter valve is provided, which is controlled by the pressure of the main fuel on the outlet of the second needle valve (38) by way of a control piston (62). With the second neeedle valve (38) opened during an injection cycle, the valve needle (60) of the interrupter valve moves into the injection bore (34) of the first needle valve (16) due to the pressure of the main fuel on the outlet of the needle valve (38) acting on its control piston (62) and interupts the ignition fuel injection for the remainder of the injection cycle. Towards the end of the injection cycle, with the second needle valve (38) closed, the valve needle (60) of the interrupter valve moves into its starting position under the force of a spring (68). This return movement of the valve needle (60) occurs with a certain time delay, so that the first needle valve (16) is already closed when the valve needle (60) of the interrupter valve frees the injection bore (34). <IMAGE>

Description

The invention relates to an injection device for Injection engines, with a valve housing, the one Feed channel for main fuel and a channel for Has ignition fuel, a liquid-controlled first needle valve for ignition fuel and a liquid speed-controlled second needle valve for main force fabric, both needle valves via separate spray holes are connected to the combustion chamber and through the pressure of the ignition fuel is controlled in such a way that in each injection cycle the ignition fuel first and then the main fuel gets into the combustion chamber.

It is known for direct injection engines Reduction of the amount of ignition fuel after it is switched on injection into the combustion chamber a second fuel, Main fuel called to enter the combustion chamber inject. It can e.g. at the ignition force fuel around diesel fuel and with the main fuel act on alcohol fuel when it is burned more environmentally friendly exhaust gases than when burning  Diesel fuel are created. However, the alcohol show fuels have a relatively high ignition temperature half the inflammation of the alcohol fuel by the that of diesel fuel must be introduced. For the injection of ignition and main fuel in direct injection engines are different types sprayers known. Doing so will burn the self-igniting ignition fuel the tempe temperature in the combustion chamber above the ignition temperature of the auto fuel that is unwilling to ignite. Ignition and main fuel must therefore be different overlapping periods in the Combustion chamber are injected.

From DE-OS 32 43 176 an injection device be knows the first liquid-controlled needle valve for ignition fuel and a second liquid controlled fuel valve for main fuel points. Both needle valves are with spray holes connected to the combustion chamber. Each needle valve has one Control chamber on that with the supply line for Zünd are connected to fuel. Both needle valves will controlled by the pressure of the ignition fuel. In addition, the second needle valve has a collection chamber on that with the supply line for main power fabric is connected. The timing of the two needle valves happen via the pressure of the Ignition fuel that first the first needle valve opens and ignition fuel is injected into the combustion chamber becomes; if the ignition fuel pressure continues to rise the second needle valve is opened and main force  substance from the collection chamber into the combustion chamber splashes. The main fuel injection will therefore accompanied by that of the ignition fuel. Towards the end of the injection phase, it closes initially the second and a short time later the first needle valve. The disadvantage of this injector is that throughout the main fuel injection pre Ignition fuel is also injected into the combustion chamber is, which makes the ignition fuel proportion relatively high is.

Another known injection device according to DE-OS 32 43 175 also has a first needle valve for Ignition fuel and two second needle valves for main fuel on. The first needle valve is over two Spray holes connected to the combustion chamber while the outlets of the second needle valves with the spray bores of the first needle valve are connected. Also in this injector are the control chambers ver of the needle valves with the ignition fuel line bound, the second needle valves each with a collection chamber are provided, from which at open neten second needle valves the main fuel in the Combustion chamber arrives. It sucks when open first needle valve flowing through the spray bores Ignition fuel the main fuel when open second needle valves due to the ejector effect the collection chambers. Also in this device be the disadvantage is that at all times span, in the main fuel in the combustion chamber reaches, also ignition fuel is injected, whereby the proportion of ignition fuel in the two-component mixture is relative is high.  

Another known injection device according to DE-OS 29 24 128 also has a first needle valve for Ignition fuel and a second needle valve for main fuel on. The control of the two needle valves done by the pressure of the main fuel. Here becomes the one in a pre-injection cylinder Ignition fuel at the beginning of the injection phase Differential piston that depends on the pressure of the main fuel is moved out of the pre-injection cylinder the control chamber of the first needle valve in the focal sprayed space. Then the second needle vein til by the increasing pressure of the main force open, and it becomes the main fuel in the Injection chamber injected. With this injector the ignition fuel is therefore exclusively before Main fuel injected, the amount of ignition fuel is constant and by the size of the front injection cylinder is determined. It is therefore independent gig of the load on the engine and the duration of the on injection cycle.

The invention has for its object a to create injection device for injection engines at which is the proportion of ignition fuel per injection cycle in Ratio to the main fuel content is low and adapted to the respective load conditions of the engine becomes.

To solve this problem, the invention provides see that in the one containing the first needle valve Channel a sub controlled by the pressure of the fuel Breaker valve is provided which when open second needle valve the ignition fuel injection interrupts.  

The injection device according to the invention has the two needle valves, which are the injection of the Control fuels, an interrupter valve. Here it is a controllable from the main fuel Valve. It is controlled by the main fuel such that when the second needle valve is open Pressure of the main force injected into the combustion chamber material used to control the interrupter valve becomes. The interrupter valve in turn interrupts the ignition fuel injection for that time in the main fuel is injected into the combustion chamber.

Shortly after the start of the main fuel injection the cut-off valve interrupts the ignition fuel feed inside the injector. This sub Refraction takes place with a certain time lag delay, so that for a short time both Zünd as well as main fuel injected into the combustion chamber will. In this transition phase he is already leading ignited ignition fuel the combustion of the in the burner space and up to the end of the injection cycle of main fuel injected into the combustion chamber a. The pressure drops towards the end of the injection phase the ignition fuel line again, so that the second needle valve closes. The break valve then takes place with a certain time delay its original state again. During this Delay time is the pressure in the ignition fuel already under the opening pressure of the first Needle valve dropped off, so that towards the end of the one injection phase no more ignition fuel into the combustion chamber reached.

In the injection device according to the invention Ignition fuel only at the beginning of an injection cycle and  before the main fuel in the combustion chamber injected, using it as an ignition aid for the head serves fuel. The amount of ignition injected fuel is not constant and adjusts the power output by the engine and the duration of the Injection cycle. Thus, over the entire speed and load range of the engine to an optimal amount Ignition fuel saved and by main fuel to be replaced, safely igniting the head fuel is always guaranteed.

According to an advantageous development of the invention it is provided that the interrupter valve is a needle valve is whose needle is downstream behind the outlet of the first needle valve in its spray hole is cash. Because the valve needle is the ignition fuel spraying by movement in the narrow spray hole of the interrupts the first needle valve, the needle and the size of the interrupter valve is small Be made so that the mass to be moved is low is.

Another advantageous embodiment of the invention is characterized in that the spray hole of the first needle valve from one of the outlet of the first needle valve to the valve seat of the lower break valve extending first subchannel and a second from the valve seat leading into the combustion chamber Sub-channel exists and that the needle of the interrupter valve when interrupting the ignition fuel spraying against his valve seat. If during the main fuel injection the break valve is driven, its valve needle presses against hers Valve seat, whereby the two sub-channels through the  Valve needle are separated from each other. Through this Type of interaction of the interrupter valve and the Spray hole of the first needle valve is reached that the dead volume within the spray hole of the first needle valve is as low as possible.

According to a further advantageous form of training Invention is provided that the break valve via a pressure hole from the pressure of the main force Controlled substance at the outlet of the second needle valve is. Here the interrupter valve only speaks open second needle valve, the pressure of the injected into the combustion chamber through the spray hole Main fuel through the pressure hole on the tax area of the interrupter valve acts, causing this the ignition fuel injection stops. The control Interruption valve is therefore only activated at opened second needle valve. This means that there is control tion and main fuel injection together.

In the injection device according to the invention for the time of the main fuel injection the on Injection of ignition fuel interrupted. The Zünd fuel is only used to ignite the main force substance at the beginning of the injection phase into the combustion chamber injected. The ignition fuel component can thus be re be reduced. The per injection phase in the combustion chamber injected fuel quantity is not constant and depends on the engine to deliver Power.

Furthermore, the ratio of the injected Amounts of fuel during the cold start phase of the engine with the help of the injection device according to the invention  vary in a simple way. The normal one Operating temperatures with diesel and main fuel operated engine can only be used during cold start Ignition fuel operated. Through one in the Main fuel supply line arranged throttle can the pressure of the main fuel depending on a reference temperature can be set such that the interrupter valve with the second needle open valve does not lower the ignition fuel injection breaks. This ensures that during the entire Injection process almost exclusively ignition fuel gets into the combustion chamber and - due to the Dros main fuel supply line - the amount of the main fuel per injection becomes. Once the engine temperature reaches the reference value exceeds, the throttling effect in the main fuel supply line lifted so that the pressure of the main fuel is sufficient, the break valve to be controlled such that during the injection of the Main fuel no ignition fuel in the combustion chamber reached.

Below is a reference to the figures Embodiment of the invention explained in more detail.

Show it:

Fig. 1 shows a longitudinal section through the injection device and

Fig. 2 is a plan view of the nozzle body from the direction of arrows II-II of Fig. 1 to illustrate the supply and distribution of the ignition and main fuel in the injector.

Referring to FIG. 1, the injection device comprises a nozzle body 10 axialgeteilten a, b and above the nozzle body 10 a, b appended to this retaining body 11. The nozzle body 10 a , b and the holding body 11 are spanned by a nozzle clamping nut 12 provided with an inner cone. The two parts 10 a and 10 b of the nozzle body are fixed relative to each other by dowel pins 14 a , 14 b in the axial direction. In part 10 b of the nozzle body there is a first liquid-controlled needle valve 16 for the ignition fuel. For this purpose, part 10 b of the nozzle body has a blind bore 15 b in which a piston is located. The piston in its upper part 16 b has a diameter which is equal to that of the blind bore 15 b . The lower part of the piston has a smaller diameter than the upper part 16 b and represents the Ven tilnadel 16 a of the first needle valve 16. Via a pressure pin 20 , the needle valve 16 is loaded by a spring 18 , the opening pressure of the needle valve 16 can be adjusted via a pressure adjusting disc (not shown).

The ignition fuel supply line is connected to a supply channel 22 leading through the holding body 11 . The feed channel 22 is connected to a pressure channel 24 , which is located in part 10 b of the nozzle body and opens into the control chamber 26 of the first needle valve 16 . The control chamber 26 is formed b by an expansion of the blind bore 15 and surrounds the transition region from the upper part 16 b of the pressure hole 15 located piston b to the lower part thereof which, as mentioned above, the valve needle 16 a of the first needle valve 16 is . The peripheral surface of the piston in the transition region from the upper part 16 b to the lower part 16 a corresponds to the control surface 28 of the first needle valve 16 , which is enclosed by the control chamber 26 . From the control chamber 26 from an annular channel 24 extends to a to by the valve needle 16 a closable blind hole 30 of the first needle valve sixteenth The annular channel 24 a results as an annular gap between the blind bore 15 b and the valve needle 16 a . A spray bore 34 leads from the valve seat 36 of the first needle valve 16 into the combustion chamber 32 .

The first needle valve 16 presses against the valve seat 36 due to the force of the spring 18 and thus blocks the spray bore 34 . The pressure of the ignition fuel located in the pressure channel 24 acts in the control chamber 26 on the control surface 28 of the first Nadelven valve 16 and opens it when the opening pressure is reached, so that the valve needle of the first needle valve 16 clears the spray hole 34 .

In addition, the injection device in part 10 a of the nozzle body has a second liquid-controlled needle valve 38 . For this purpose, in part 10 a of the nozzle body there is a blind bore 15 a , which consists of an upper and a lower section, the upper section being larger in diameter than the lower section. The piston in the blind bore 15 a is placed comprises c an upper part 38, a mitt-sized portion 38b and a lower portion which tapers at the end and illustrating the valve needle 38 a of the second needle valve 38th The diameter of the upper part 38 c and the diameter of the middle part 38 b corresponds to the diameter of the upper section or middle section of the blind hole 15 a , while the diameter of the valve needle 38 a is smaller than the diameter of the lower section of the blind hole 15 a is. The control chamber 40 of the second needle valve 38 is designed like the control chamber 26 of the first needle valve 16 and encloses the peripheral surface of the piston functioning as the control surface 44 of the second needle valve 38 in the transition region from its upper part 38 c to its central part 38 b . The control chamber 40 of this needle valve is connected via a pressure channel 42 according to FIG. 2 with an annular channel 43 which connects the pressure channels 24 and 42 and to which the inlet channel 22 for ignition fuel leads. The pressure channel 42 is located in part 10 a of the nozzle body and ends in the control chamber 40 . The pressure of the ignition fuel passing through the pressure channel 42 into the control chamber 40 acts on the control surface 44 of the second needle valve 38 and raises it against the force of a spring 46 loading the second needle valve 38 , the tension of which is brought up via the pressure bolt 48 onto the needle valve 38 and is adjustable via a (not shown) pressure adjusting disc. The control of the second needle valve 38 is carried out exactly like that of the first needle valve 16 by the pressure of the ignition fuel.

In addition to the control chamber 40 , the second needle valve 38 has a collecting chamber 50 which is designed like the control chamber 40 and is arranged downstream behind the control chamber 40 . The collecting chamber 50 encloses the piston inserted into the blind bore 15 a in the transition region from the central part 38 b to the valve needle 38 a . The (not shown) main fuel supply line is connected via an inlet channel 52 , which leads through the holding body 11 , to the supply channel 54 , which runs in part 10 a of the nozzle body and extends to the collecting chamber 50 . Therefrom, an annular channel 54 a leading to the by the valve needle 38 a closable blind hole 56 of the second needle valve 38th The annular channel 54 a results as an annular gap between the blind bore 15 a and the Ven tilnadel 38 a of the second needle valve 38 . From the pocket hole 56 , two or more spray holes 58 a , b extend into the combustion chamber 32 .

When the second needle valve 38 is open, the main fuel passes through the feed channel 54 , the collecting chamber 50 , the ring channel 54 a , the blind hole 56 and the spray bores 58 a , b into the combustion chamber 32 . The main fuel has a pressure suitable for injection, which can be lower than the pressure of the ignition fuel required to control the two needle valves 16 and 38 .

Between the spray channels 58 a and 58 b of the second needle valve 38 and the spray bore 34 of the first needle valve 16 , a further liquid-controlled needle valve 59 is arranged transversely, which acts as a cut-off valve and interrupts the injection of the ignition fuel during the main fuel injection. The needle valve 59 has a Ven tilnadel 60 , at the blind hole 56 of the second needle valve 38 facing end is a control piston 62 which is guided in a bore 64 made in part 10 a of the nozzle body. The bore 64 is connected to the blind hole 56 of the second needle valve 38 via a pressure bore 66 . The tapered end of the valve needle 60 can be moved laterally into the spray bore 34 of the first needle valve 16 . The spray bore 34 of the first needle valve 16 is divided into two sub-channels 34 a , 34 b , of which the first sub-channel 34 a leads from the valve seat 36 of the first needle valve 16 to the valve seat 72 of the needle valve 59 . The second subchannel 34 b extends from the valve seat 72 to the combustion chamber 32 . Instead of only one second part of the channel 34 b, as shown in Fig. 1, a plurality of second sub-channels are possible which open in different directions into the combustion chamber 32. When the valve needle 60 of the Nadelven valve 59 moves in the direction of its blind hole 61 , the spray bore of the first needle valve 16 is blocked by the valve needle 60 pressing against the valve seat 72 ver.

In the idle state, the needle valve 59 is biased towards its open position by a spring 68 . The spring 68 engages with its one end on a disk 70 which is located between the control piston 62 and the valve needle 60 and is fixedly connected to the latter. With its other end the spring 68 of the nozzle body is supported against the end face in the part 10 b machined cylindrical cavity 69 from which can be connected directly with the bore 64th The longitudinal axis of the cylindrical cavity 69 and the bore 64 coincide with the longitudinal axis of the valve needle 60 . With the help of a arranged between the spring 68 and the disk 70 pressure adjusting disk 71 , the tension of the spring 68 and thereby the response characteristics of the interrupter valve can be changed and adapted to the special requirements of an engine.

Due to the high pressure of the ignition fuel in the spray bore 34 when the first needle valve 16 is open, a small part of the ignition fuel passes along the valve needle 60 of the needle valve 59 into the cylindrical cavity 69 . The cavity 69 is connected to the combustion chamber 32 via a bore 74 . Via the bore 74 , the portion of the ignition fuel which reaches the cavity 69 as a leakage liquid can be discharged into the combustion chamber 32 . The valve needle 60 of the needle valve 59 and the control piston 62 of the needle valve 59 are thus lubricated by the ignition fuel.

The following describes diesel and main fuel injection during an injection cycle. The increasing pressure of the ignition fuel at the beginning of the injection phase acts on the control surface 28 of the needle valve 16 for the ignition fuel and opens it. The valve needle 60 of the interrupter valve in its rest position does not block the spray bore 34 of the first needle valve 16 , so that the ignition fuel is injected into the combustion chamber 32 . Shortly after the first needle valve 16 , the further increasing pressure of the ignition fuel also opens the second needle valve 38 , which is set to a higher opening pressure. Main fuel now enters the combustion chamber 32 through the injection bores 58 a , b via the feed channel 54 , the ring channel 54 a and the blind hole 56 . Ge also reaches main fuel through the pressure bore 66 in the part 67 of the bore 64 , in which the control piston 62 of the interrupter valve moves. The pressure of the main fuel thus acts on the end face of the control piston 62 which acts as the control surface of the break valve, whereby the break valve is moved against the force of the spring 68 , and thereby the valve needle 60 of the break valve is pressed against its valve seat 72 and thus the spray bore 34 blocked. Thus, despite the first needle valve 16 being opened, no ignition fuel is then injected into the combustion chamber 32 .

During this phase, only main fuel enters combustion chamber 32 . This can reduce the amount of ignition fuel per injection cycle. Only in a short transition phase from the beginning of the main fuel injection to the complete closure of the spray bore 34 through the valve needle 60 of the interrupter valve, both types of fuel enter the combustion chamber. The ignition fuel already injected into the combustion chamber 32 ignites the main fuel, the combustion of which is maintained until the end of the injection cycle with the main fuel injected further into the combustion chamber 32 . At the end of the injection phase dropping pressure of the ignition fuel first closes the second needle valve 38 , whereby the valve needle 60 of the interrupter valve with the pressure of the main fuel now falling at the outlet of the second needle valve 38 moves back to its starting position due to the spring 68 . However, this process takes place with a certain time delay, so that the pressure of the ignition fuel has already dropped to below half the opening pressure of the first needle valve 16 and thus no ignition fuel reaches the combustion chamber towards the end of the injection phase. The time delay with which the movement of the valve needle 60 in its starting position is achieved by the fact that the diameter of the cylinder 64 in which the control piston 62 of the interrupter valve moves is substantially larger than the diameter of the pressure bore 66 , whereby a throttling effect occurs when the valve needle 60 moves back.

With the help of the injector, the ignition force proportion of substance per injection cycle reduced and thus Ignition fuel can be saved. The pro Injection cycle amount of ignition fuel injected each not constant, but rather based on it the instantaneous power demanded by the engine  and the duration of the injection cycle. Over the whole Engine speed range will ignite safely of the main fuel made possible by the ignition fuel light, because in a short period of time both forces substances are injected at the same time, the at Main fuel injection starts in the combustion chamber Ignition fuel located ent the main fuel ignites. After that, the will continue to turn on main fuel injected the pilot fuel spray through the break valve until the end of the Injection phase interrupted. Thus, in all directions optimal number and load ranges of the engine Amount of ignition fuel replaced by main fuel always with a gentle main fuel ignition is done.

Claims (6)

1. Injector for injection engines, with a valve housing which has a feed channel for main fuel and a channel for ignition fuel, a liquid-controlled first needle valve for the ignition fuel and a liquid-controlled second needle valve for the main fuel, both needle valves via separate spray bores with the combustion chamber are connected and controlled by the pressure of the ignition fuel such that in each injection cycle first the ignition fuel and then the main fuel enters the combustion chamber, characterized in that in which the first needle valve ( 16 ) contains channel ( 24 ) from Pressure of the fuel controlled interrupter valve is provided which interrupts the ignition fuel injection when the second needle valve ( 38 ) is open. 2. Injector according to claim 1, characterized in that the interrupter valve is a needle valve ( 59 ), the needle ( 60 ) downstream downstream of the outlet of the first Nadelven valve ( 16 ) in the spray bore ( 34 ) is movable. 3. Injector according to claim 1 or 2, characterized in that the spray bore ( 34 ) of the first needle valve ( 16 ) from a from the outlet of the first needle valve ( 16 ) to the valve seat ( 72 ) of the interrupter valve extending first sub-channel ( 34 a ) and one from the valve seat ( 72 ) into the combustion chamber ( 32 ) leading second sub-channel ( 34 b) and that the needle ( 60 ) of the interrupter valve presses against its valve seat when the ignition fuel injection is interrupted. 4. Injector according to one of claims 1 to 3, characterized in that the sub-breaker valve is controlled via a pressure bore ( 66 ) from the pressure of the main fuel at the outlet of the second needle valve ( 38 ). 5. Injector according to one of claims 1 to 4, characterized in that the sub-break valve between the spray bores ( 34 , 58 a , b) of the two needle valves ( 16 , 38 ) is arranged transversely to these. 6. Injector according to one of claims 1 to 5, characterized in that the sub-breaker valve is biased towards its opening position by a spring ( 68 ), the voltage of which can be changed by a pressure adjusting disc ( 71 ).