US3906913A

US3906913A - System for minimizing internal combustion engine pollution emission

Info

Publication number: US3906913A
Application number: US387342A
Authority: US
Inventors: Jack H Rupe
Original assignee: California Institute of Technology CalTech
Current assignee: California Institute of Technology CalTech
Priority date: 1973-08-10
Filing date: 1973-08-10
Publication date: 1975-09-23
Anticipated expiration: 1992-09-23
Also published as: AU7235074A; DE2438217A1; IT1019838B; SE7410204L; JPS5082430A; GB1485836A; FR2240361A1; SE407264B; CA1020421A

Abstract

A mixing device is provided for an internal combustion engine which simultaneously atomizes liquid fuel, mixes this fuel with an optimal quantity of hydrogen and combines this mixture with a prescribed quantity of air. A throttling mechanism controls the fuel delivery to the engine and also limits the fuel to air equivalence ratio to be predetermined upper bound to inhibit the production of air pollutants and to a lower bound which is above the lean flammability of the mixture.

Description

United States Patent [191 Rupe SYSTEM FOR MINIMIZING INTERNAL COMBUSTION ENGINE POLLUTION EMISSION Inventor: Jack H. Rupe, Sunland. Calif.

California Institute of Technology, Pasadena. Calif.

Filed: Aug. 10, 1973 Appl. No.1 387,342

Assignee:

US. Cl 123/121; l23/DIG. 12; 123/119 E;

l23/l20; l23/l98 A Int. Cl. F02m 13/08 Field of Search l23/DIG. 12, H9 E, 121,

References Cited UNITED STATES PATENTS Atwood l23/DIG. I2

[451 Sept. 23, 1975 2,482,531 9/1949 Young et al. l23/DIG. 12

Primary Examiner-Wendell E, Burns Attorney, Agent, or FirmLindenberg, Freilich, Wasserman, Rosen & Fernandez [57] ABSTRACT A mixing device is provided for an internal combustion engine which simultaneously atomizes liquid fuel, mixes this fuel with an optimal quantity of hydrogen and combines this mixture with a prescribed quantity of air. A throttling mechanism controls the fuel delivery to the engine and also limits the fuel to air equivalence ratio to be predetermined upper bound to inhibit the production of air pollutants and to a lower bound which is above the lean flammability of the mixture.

18 Claims, 8 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of 5 3,906,913

WEE Q: :35 $522 mDu 58x5: mom :23 M152:

01 1 (ILLS lON W9) US Patent Sept. 23,1975 Sh eet 2 01-5 3,906,913

FIG. 2

US Patent Sept. 23,1975 Sheet 3 01 5 3,906,913

TO HYDROCARBON SUPPLY TO HYDROGEN SUPPLY k i H 2 54 56 FIG. 3 \g FIG. 4

INDICATED US Patent Sept. 23,1975 Sheet 4 0f5 3,906,913

lL-J 1/04 5 l I i I l I 8.

FIG. 6

DEMAND 90 AVAILABLE I ,UPIPER I EQIUIV RATIO BOUND HFLAMMABILITY 7 0 LIMIT- W.O.T.

s0 AIR THROTTLINGO x REQUIREDO FOR m g CONST mIDLE 1,5 40 E 3 30 O Q. LU 20 0 I l0 7 IDLE FUEL FLOW q I 75ORPM I I I I I I I I I I 0 I000 2000 3000 4000 5000 ENGINE SPEED RPM FIG. 7

US Patent Sept. 23,1975 SheetS 0f5 3,906,913

mzazw OF SYSTEM FOR MINIMIZING INTERNAL COMBUSTION ENGINE POLLUTION EMISSION ORIGIN OF THE INVENTION The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; 42 USC 2457).

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and means for rendering an internal combustion engine substantially air-pollution free, and more particularly to im* provements therein.

2. Description of the Prior Art A great deal of investigation has gone into the problem of reducing the pollutants emitted by an internal combustion engine which uses a hydrocarbon fuel. It has been recognized that carbon monoxide and other emissions have been found to decrease as the fuel to air ratio is made leaner. The fuel to air ratio is also known as the equivalence ratio when it is compared to the stoichiometric value for that fuel. However, in either case as the mixture is made fuel lean, a point is very soon reached where the mixture is no longer flammable. Thus, it appears desirable to have a means to extend the equivalence ratio into the ultra lean region still providing flammability, whereby pollutant emissions from the internal engine may be minimized. Since the load requirements on the engine are variable, it is also necessary to control the equivalence ratio of the fuelair mixture in an engine over the range of load applied, within a lean mixture range, if the engine is to operate and be substantially pollutant free.

A patent to Blumenberg, US. Pat. No. 1,379,077, teaches passing hydrogen and oxygen gases through a heavy hydrocarbon fuel to facilitate its vaporization. A patent to Ricardo, US. Pat. No. 1,520,772, teaches mixing a fixed amount of hydrogen and a fixed amount of air with a hydrocarbon fuel whose quantity can be varied from zero to a maximum value over the range from no load to a maximum load. The hydrocarbon and hydrogen are mixed in the absence of air, and then are mixed with the air in the piston of the engine. A patent to Bogan, US. Pat. No. 3,653,364, teaches how to produce hydrogen gas and then introduce it into the intake manifold below the carburetor to be mixed with fuel and air. The hydrogen gas is for the purpose of providing higher combustion temperatures thus reducing the quantity of unburned hydrocarbons which are exhausted into the atmosphere.

Mixing hydrogen with a hydrocarbon fuel-air mixture can extend the flammability limits, but no one has .taught how to maintain control at all times when hydrogen is used, over an upper and lower boundary on the fuel-air equivalence ratio over the wide range of speed and lower requirements of an automobile engine. This problem becomes complicated by virture of the fact that a mixture of two (or more) fuels are being used for which the quality" (mass fraction of one fuel in the total) of the fuel is constantly changing. The use of a constant hydrogen flow and unrestricted air flow as taught by the prior art does not solve the problem.

OBJECTS AND SUMMARY OF THE INVENTION An object of this invention is the provision of an improvement in an internal combustion engine whereby it will produce substantially no air pollutants.

Another object of this invention is the provision of a hydrogen-fuel-air mixing system which minimizes the amount of pollutants produced by an internal combustion engine over its operating range.

Still another object of the present invention is the provision of a system for maintaining a mixture of hydrogen-fuel and air for an internal combustion engine within predetermined boundary limits over the engine operating range.

Yet another object of the invention is the provision of a novel and useful fuel-air mixture control for minimizing the emission of pollutants by an internal combustion engine.

The foregoing and other objects of the invention may be achieved by providing an induction system for an internal combustion engine which uses an internal variable area fuel control valve u.nder throttle control for mixing hydrogen and fuel to maintain predetermined proportions over the operating range of the engine. A throttle override control is used to maintain an upper bound for the mass flow of this mixture relative to any given air flow over the engine operating range. The air flow to the engine is also controlled by the throttle in a manner to assure that the equivalence ratio of the hydrogen-fuel-air mixture is maintained within prescribed bounds and to assure combustible mixtures at high engine speeds when minimal amounts of power are required.

The novel features of the invention are set forth with particularity in the appended claims. The invention will best be understood from the following description when read in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a curve illustrating the characteristic correlation between specific emissions (N0 and equivalence ratio for a spark internal combustion engine.

FIG. 2 is a schematic drawing of an automobile illustrating'placement of the various components of a system in accordance with this invention.

FIG. 3 is a schematic drawing illustrating the layout of an induction system, in accordance with this invention.

FIG. 4 is a drawing of a fuel flow control valve which is in the induction system together with the override control.

FIG. 5 is a view in section illustrating the cam and passages within the fuel flow control valve.

FIG. 6 is a side view of the fuel flow control valve.

FIG. 7 shows a series of curves illustrating the performance bounds of an engine in accordance with this invention.

FIG. 8 is an illustration of a hydrogen generator which may be employed with this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The curve 8, FIG. 1, represents the characteristic correlation between specific emissions, which here is NO,, and equivalence ratio for a spark internal combustion engine. This curve can be modified by any one of a number of operating variables, such as spark advance, compression ratio, engine speed, etc., but if one maximizes performance and efficiency of the combustion process, and normalizes the NO formation to the I heat added during each combustion cycle, then the dominance of stoichiometry in the correlation of NO, formation is always observed. The curve indicates a characteristic maximum occurring at a location (0.83-0.85 equivalence ratio) which is slightly lean from the stoichiometric mixture, (1.0 equivalence ratio).

If in an attempt to control NO, emissions, one operates a conventionally fueled engine (e.g., gasoline) very lean, the engine begins to misfire as the engine approaches the flammability limit of the fuel, (0.7 equivalence ratio). Unfortunately this limit occurs for mixtures with relatively high NO, formation rates and therefore imposes severe limitations on the lean limit operation, for. conventional fuels. On the other hand, hydrogen is unique in this regard since it exhibits flammability limits that are only 13 percent of its stoichiometric mixture (volume basis). Hence, as indicated in FIG. 1, it is possible to reduce emissions of NO, to essentially zero (less than 1 ppm) simply by using H as the fuel and operating at very low equivalence ratios.

insofar as the other emissions are concerned, i.e., CO and unburned hydrocarbons, it can be shown that even withcarbonaceous fuels, operation near the lean flammability limit is an effective control technique. Obviously, if the fuel is 100% H these fuels are not generated in the combustion process.

Thus, in summary, all fuels exhibit similar emission characteristics, (when properly normalized) which can be reduced to negligible quantities if the combustion process takes place at low equivalence ratios (less than 0.6 for example). Since it is now recognized that these properties are exhibited by all fuels, it follows that mixtures of hydrogen and hydrocarbons will behave in a similar manner with reduction in emissions being limited only by the flammability limits of the mixture. Thus, the well-known laws for flammability limits of fuel mixtures serve as the basis for establishing the lean equivalence ratio bounds that assure flammability while the emission data typified by Curve 8 of FIG. I serve to establish the upper limit that will be allowed regardless of engine operating conditions.

It has been found that extension of the misfire limits to very lean equivalence ratios with hydrogen fuel also yields significant increases in thermodynamic efficiency of the combustion process. Efficiency is not fuel dependent and the extension of the misfire limit using hydrogen fuel provides efficiency increases of nearly 100% relative to the value obtained at the stoichiometric mixture. Thus, if an engine can be run on hydrogen near its misfire limit, substantial gains in fuel economy are possible.

There is a decrease in specific horsepower (horsepower for a given engine size) which accompanies the decrease in specific energy (heat release per cycle) when an engine is operated with a very lean mixture. It has been observed that this property is not fuel dependent except to limit the operating range (misfire limit) for carbonaceous fuels. When the operating range is extended to the misfire limit of hydrogen, (where minimum emission and maximum efficiency occur), then relative horsepower, (actual horsepower relative to the maximum attainable at that speed), is reduced to of maximum. This is really 'just a scaling problem since in concept a hydrogen fueled engine could be increased in size to recover the reduced horsepower if that were deemed essential. It will become apparent however that this will not be necessary since an operating system, in accordance with this invention, utilizes this characteristic as a throttling mechanism.

In a particular embodiment of this invention an arrangement is provided wherein hydrogen or a hydrogen rich gas is supplied to an engine as the working fluid of a pneumatic atomizer at a quantative rate sufficient to supply percent of the energy needs for the engine at idle conditions and, by way of illustrating, at an equivalence ratio on the order of 0.15. One of several alternate arrangements would provide for a variable hydrogen flow rate (e.g. proportional to engine speed) which would decrease the amount of air throttling required and hence yield slightly higher overall average operating efficiencies. However, this system would introduce the additional complexity of hydrogen throttling (as well as air throttling) in order to satisfy the low power, high engine speed operating requirements. Hence, in illustration of the invention, the preferred embodiment will utilize the constant and minimal hydrogen flow indicated above.

The pneumatic atomizer is mounted in the intake system and atomizes the liquid fuel being supplied to the engine. The liquid fuel delivery system for supplying fuel to the atomizer is demand controlled to provide varying stoichiometry to the engine. An override of the fuel delivery system, which is air flow sensitive, is provided to limit the maximum mixture equivalence ratio to a predetermined value on the order of 0.6 for example, in order to minimize NO, formation.

FIG. 2 shows an illustration of an automobile 10, having an engine 12, and a tank 14, in which the hydrocarbon fuel is kept. In accordance with this invention, the engine is equipped with an induction tube 16, wherein there is located a fuel flow control valve and throttle override therefore, as well as a pneumatic atomizer, for atomizing the fuel and mixing with hydrogen gas. The fuel flow control valve is controlled from the foot pedal by the operator.

There is also provided an air throttle 18 which is coupled to the fuel flow control valve, and in consonance with fuel flow requirements determines the amount of air permitted to flow to the engine through the induction tube. The hydrocarbon fuel is fed into the pneumatic atomizer in the induction tube through a pipe 22 in which there is a fuel pump 24.

The hydrogen rich gas supply for this invention may come from any source. Any of the known types of hydrogen generators may be employed. However, by way of example, and not by way of limitation, a hydrogen generator of the type described and claimed in an application entitled, Hydrogen Generator", by Houseman, et al., filed Aug. 20, 1973, Ser. No. 390,049, and assigned to a common assignee. This hydrogen generator generates hydrogen rich gas from the hydrocarbon fuel used by the engine and water using the steam reforming process. A pipe 26 branches from the pipe 22 to couple to a pump 28, which is used to supply hydro carbon fuel to the hydrogen gas generator 20. A water supply coupled to a pump 34' whereby water is provided to the hydrogen generator. An air pump 36, is also employed for applying air under pressure to the hydrogen generator 20.

Referring now to FIG. 3, there is shownan induction tube 16 in section, which, in accordance with ;this invention, contains the flow control-valve40, which is controlled by the vehicle operator by means of the throttle rod 42 and rod coupling 43. Hydrocarbon fuel is brought to the flow control-valve by tube 26 and hydrogen rich gases are brought from a supply, by the tube 44. The flow control valve 40 is connected to fuel atomizer 46. An override control 48 is used to limit the amount of hydrocarbon fuel being supplied by the flow control valve for any given engine speed in response to pressure in the venturi which is established by the mass air flow to the engine to limit the maximum mixture ratio to a suitable value for suitably inhibiting the formation of NO,,. The details of the operation of the override control 48 are discussed in connection with the description of FIG. 4.

The induction tube is coupled to the engine intake manifold 50, which, because it is so well known, is shown as a fragment. The coupling passage between the induction tube and the intake manifold contains an air throttle section in which two air throttle valves, respectively 54, 56, are positioned to control the air intake into the engine, in response to the throttle rod 42 position, which is positioned by the vehicle operation in response to power demands. Two air throttle valves are shown by way of example and not by way of limitation. One or more may be used without departing from the spirit or scope of the claims.

The

air throttle

54, 56, is actuated in such a way that the air flow is dictated by a known relation between gasoline flow rate (set by fuel throttle valve) and the air flow in order to assure a mixture bound that is greater than the lean flammability limit of the fuel mix. As the fuel demand (i.e., power load) decreases at high engine speeds the fuel flow control valve is driven toward the closed position. When this happens the air is also throttled in order to maintain the fuel-to-air 'mass flow within the prescribed flammability limit. However, in view of the fact that the fuel quality is then dominated by hydrogen, the engine will operate at very lean equivalance ratios. Hence, the throttling requirements are approximately one-sixth of those needed for conventional systems. Further, at lessor engine pumping speeds the need for air throttling is proportionately reduced. The combination of these effects provide the basis for the simple mechanically linked system indicated in FIG. 3.

The pneumatic atomizer 46 simultaneously mixes the hydrocarbon fuel with the supply of hydrogen rich gases and produces a very fine mist. The inducted air mixes with this mist and is urged into the intake manifold and then into the engine. The flow control valve, as previously indicated, is demand controlled by the driver using the throttle pedal. The throttle override is used to determine the maximum hydrocarbon fuel flow rate so that it is at a value consistent with an upper limit equivalence ratio of approximately 0.6, which has been determinedas the upper bound necessary to best in-"i' and the exterior of the flow control valve 40. The piston is attached to a flexible cable 62 which is keyed to a pulley 64 bya dog 65 and held in tension around theperiphery of the pulley by means of a spring 66. The spring 66 isattached to the wall of the induction tube. The pulley rotates about a center 67 and rotates with it a cam 68. The cam surface can engage a cam follower 69, mounted on throttle extension 43 to block further motion to the right and thus inhibits flow of ad ditional fuel.

FIG. 4 shows several positions of the extension arm 43, which couples the throttle rod 42 to the flow control valve 40. The throttle closed position is at the extreme left and is represented by the dotted lines. The maximum open throttle at maximum RPM is at the extreme right and is represented by the dotted lines. The solid line position between the two, represents maximum throttle at idle RPM. The pressure of the air in the venturi throat section of the induction tube determines the position of the piston 60. The piston pulls against the spring 66 in response to the vacuum caused by the venturi and thus, variations in air pressure cause different piston positions which cause rotation of pulley 64 and with it cam 68. In this manner, the position assumed by the cam is determined by the air pressure or air depression established at the venturi by the air flow to the engine. The cam position determines the maximum amount of hydrocarbon fuel which can be provided to the engine for any given engine speed. This is established in compliance with a predetermined relationship to the air flow rate. The air flow rate is detected from the static pressure produced in the throat of the venturi. By this means, the equivalence ratio of the fuel plus air mixture can be limited to a selected maximum value, which has been found to be on the order of 0.6 at which value production of N0 is substantially eliminated.

FIGS. 5 and 6 respectively show a cross-sectional view of the pneumatic atomizer with an integral flow control valve and a cross-sectional view along the lines 5-5 of FIG. 4. The hydrocarbon fuel line 22 feeds the fuel into a substantially circular opening, defined by walls 70, within which space a valve member 72, is rotated by the throttle 43. The opening 70 communicates with an exit passageway 74, which ends in an exit passage 76, which is considerably narrower than the passageway 74.

The line 24 containing the pneumatic atomizer working fluid communicates with a frustrated conicular region, defined by the

walls

78, 80, which surrounds the exit passageway 76 which is concentric therewith. The conicular region terminates in an opening 82. The narrow exit passageway 76 ends just short of the opening 82, as a result of which the hydrogen gas and the hydrocarbon fuel spray mix at the exit opening 82 and are ejected into the induction passageway of the induction tube.

.It should be noted that the shape of the valve member 72is such that when the throttle arm is in the throttle closed position, it blocks the passageway 74 and therefore, no hydrocarbon fuel will be supplied to the engine; The shape of the valve member is contoured to provide a desired rate of flow of hydrocarbon fuel with throttle position, whereby engine speed may be controlled.

FIG. 7 presents a series of curves illustrating equivalence ratio, (ER), throttling of a spark ignition engine.

The curves labeled ER=0.1 through 1.0 are for wide open throttle operating conditions and assume sufficient hydrogen available to satisfy the horsepower requirements illustrated by the 0.1 BR line. These curves are analogous to a conventional representation where they would represent mass flow throttling to give respectively 25, 35, 63, 87, and 97 percent of the maximum power available at any given engine speed. It is seen that with equivalence ratio throttling, engine power is varied on demand by varying fuel flow while equivalence ratio is allowed to vary with either fuel flow or engine speed. In conventional engines, power is adjusted by changing the mass density of the combustion charge (and hence energy) for a substantially constant mixture ratio. Superimposed on this operating map is the flammability limit curve which bounds the cross hatched region where air throttling is required when the hydrogen flow is constant and equal to idle energy requirements. In this system, the engine burns a fuel that is pure hydrogen at idle and a fuel that is a mixture of perhaps 90% liquid fuel and 10% hydrogen at maximum horsepower, (also maximum equivalence ratio and high engine speed), condition. For the low load conditions where the bulk of the driving is done, it is estimated that the fuel mixture would vary between 5 and 25% hydrogen and hence emissions and efficiency tend to be simultaneously optimized.

FIG. 8 is a drawing illustrating a hydrogen gas generator which may be employed to provide hydrogen rich gas to an engine, in accordance with this invention. This is shown by way of illustration of hydrogen rich gas and not by way of limitation. An electric motor 90 drives an air pump 36, a gasoline pump 28 and a water pump 34 to provide these fluids to the gas generator over the

respective pipes

92, 94 and 96. The hydrogen rich gas generator includes two portions respectively 98 and 100 which include chambers which have the same axis and communicate at one end with each other.

The first portion has cylindrical walls 102 which enclose a first chamber. At one end of this chamber is a pneumatic atomizer 104 to which air, as the operating fluid, and the hydrocarbon fuel are supplied to atomize the fuel. The air is supplied directly from the high pressure discharge of the air pump 36.

The second portion 100 of the hydrogen generator has outer cylindrical walls 105. These enclose inner cylindrical walls, which are spaced therefrom and define a second chamber, which is the burning chamber. Between the first and second walls is a spiral wall 108, which defines a spiral passage. Air is pumped into one end of the spiral passage over the pipe 92, to be directed around the inner walls 106 and thus, is preheated by the inner chamber walls which surround the burning chamber.

The fuel-air mixture created in the first chamber is passed into the second chamber through an air swirler. This comprises a toroid with a plurality of passages which are angularly directed from the outer periphery of the toroid ring to the central opening. Preheated air from the spiral passage passes through these angularly directed openings and causes the air-fuel mixture passing through the central opening of the air swirler 112 to be swirled as it enters into the burning chamber. A spark plug 114 ignites this mixture and the hot gases which are created pass further into the chamber where there is sprayed a mixture of gasoline and water through a secondpneum atic atomizer 116.

The gasoline and water are supplied to the pneumatic atomizer over

pipes

94 and 96. High pressure air is also provided as the atomizer working fluid over a pipe 118. The hot gases in the second chamber convert the water spray in the fuel-water mixture into steam. The fuel is vaporized and a steam reforming action takes place within the reactor space formed by the burning chamber. Hydrogen rich gas passes out of the opening 120 to the induction tube of the engine.

For start up, the vehicle ignition switch will also energize the motor which causes delivery of air to the hydrogen generator. After a suitable delay interval to allow air pressure to build up to a predetermined value, such as 5 psi, or when the pressure is sensed by a pressure sensitive switch, the engine cranking system is activated, the engine and hydrogen generator ignition systems are activated and the magnetic clutch that couples the water and fuel pumps, respectively 34, 28, to the motor drive are activated. This produces hydrogen substantially instantaneously and the engine then bootstraps itself to the idle condition.

There has accordingly been described and shown herein a novel and useful system for operating an internal combustion engine in a manner to substantially eliminate combustion products which cause air pollution, while effectively reducing the amount of hydrocarbon fuel which is consumed.

In the foregoing application, and in the claims, it should be understood that the word hydrogen is used as an abbreviation for hydrogen rich gas. The invention does not require pure hydrogen gas. The hydrogen rich gas may contain considerable fractions of inert and flammable material.

What is claimed is: l. A system for minimizing the air pollution output of an internal combustion engine comprising an induction system for said engine having means for mixing a hydrogen rich gas, a liquid fuel and air;

means for controlling said means for mixing over the operating range of said engine to provide a gas. fuel and air mixture in proportions within predetermined upper and lower equivalence ratio bounds and yet are within the flammable range of said mixture which minimize air pollution by said engine, and

means for applying the output of said means for mixing to said internal combustion engine.

2. A system as recited in claim 1 wherein said means for mixing includes a pneumatic atomizer for atomizing fuel and mixing fuel with hydrogen rich gas, and

air valve means for controlling the amount of air permitted to flow to said internal combustion engine together with-said mixture of fuel and gas.

3. A system as recited in claim 2 wherein said means for controlling said means for mixing includes a throttle controlled fuel control valve means for controlling the amount of fuel supplied to said pneumatic atomizer;

means for sensing the mass air flow to said engine and producing a representative control effect, and

override means responsive to said mass air flow control effect for limiting to a predetermined value the maximum amount of fuel supplied by said flow control valve to said pneumatic atomizer over the operating range of said engine.

4. A system as recited in claim 3, wherein said means for sensing the mass air flow to said engine and producing a representative control effect, includes an induction tube for supplying air to the manifold of said engine,

means for establishing a venturi in said induction tube, and Y means for measuring pressure variations of the air passing through said venturi and producing a control effect responsive thereto.

5. A system as recited in claim 1 wherein said means for controlling controls said means for mixing to produce, over the operating range of said engine, a gas, fuel and air mixture which is within the flammable range for the mixture and which does not exceed an upper bound equivalence ratio of approximately 0.6.

6. A system for minimizing the air pollution output of an internal combustion engine, comprising an induction system including walls defining an air induction tube, said induction tube being coupled to the manifold of said internal combustion engine, a fuel supply control system positioned within said induction tube and dimensioned to form an air venturi with the induction tube walls adjacent thereto,

means for supplying hydrocarbon fuel to said fuel supply control system,

means for supplying hydrogen rich gas to said fuel supply control system,

valve means in said fuel supply control system for controlling the amount of hydrocarbon fuel permitted to pass through said fuel control system, said fuel supply control system further including means for mixing and emitting hydrocarbon fuel and hydrogen gas into said induction tube,

override means responsive to air pressure caused by mass air flow through said venturi for limiting the amount of hydrocarbon fuel that can be passed through said fuel control system to a predetermined value, and

throttle control means, operative in conjunction with said valve means for controlling the amount of air passing from said induction tube into said engineintake manifold to maintain a fuel-air mixture ratio which minimizes the air pollution output of said engine.

7. A system as recited in claim 6 wherein said means for mixing and emitting hydrocarbon fuel and hydrogen gas into said induction tube comprises a pneumatic atomizer,

means for supplying hydrocarbon fuel from said valve means to said pneumatic atomizer, and means for supplying said hydrogen rich gas to said pneumatic atomizer as a working fluid to mix said hydrocarbon fuel as a fine mist with said gas.

8. A system as recited in claim 6 wherein said valve means in said fuel supply control means for controlling the amount of hydrocarbon fuel passing therethrough includes walls defining a substantially circular cavity,

a fuel entrance passageway at one side of said cavity,

a fuel exit passageway at another side of said cavity,

and

a rotatable throttle control cam means for establishing the size of the passageway through said circular cavity between said entrance passageway and said exit passageway from a blocked position when said engine is producing idle power requirements to a predetermined maximum opening which is correlated to engine speed.

9. A system as recited in claim 6 wherein said override means for limiting the maximum amount of fuel passed by said fuel supply control means includes walls defining a chamber, a piston within said chamber, air passage means for enabling air pressure communi cation between said chamber and said air venturi, for determining the position of said piston responsiveto said air pressure, and 1 means responsive to the position of said piston for preventing operation of said valve means to increase the flow of hydrocarbon fuel through said 'fuel supply control system beyond a predetermined maximum amount as specified for each engine speed.

10. In an internal combustion engine a system for eliminating noxious emissions from said engine comprising a source of hydrocarbon fuel,

a source of hydrogen rich gas,

an induction system including an air intake induction tube,

said tube containing throttle controlled fuel supply means,

means establishing a venturi passage within the walls of said induction tubes,

pipe means for bringing said hydrocarbon fuel and said hydrogen rich gas from said source of hydrocarbon fuel and said source of hydrogen to said throttle controlled fuel supply means, said throttle controlled fuel supply means including wall means forming a pneumatic atomizer for atomizing said hydrocarbon fuel and mixing it with said hydrogen rich gas to form a fuel mixture,

override control means responsive to the pressure in said venturi passage established within said induction tube for limiting to a predetermined maximum amount for each specified engine speed the amount of hydrocarbon fuel supplied by said throttle controlled fuel supply means,

means coupling said induction tube to said engine,

and

a throttle controlled means in said means coupling said induction tube to said engine for controlling the air supplied thereto to maintain the mixture ratio of the fuel mixture to air at all times within the flammable range of the fuel mixture to air and not to exceed an upper bound of approximately 0.6.

11. ln an internal combustion engine as recited in claim 10 wherein said throttle controlled fuel supply means includes a variable area fuel control valve for supplying hydrocarbon fuel to said pneumatic atomizer,

movable throttle rod means for controlling said variable area fuel control valve for determining the amount of hydrocarbon fuel flow to said pneumatic atomizer.

12. In an internal combustion engine as recited in claim 11 wherein said variable area fuel control valve includes means for closing off the hydrocarbon fuel supplied to said pneumatic atomizer when said mov able throttle rod means assumes an engine idle position.

13. In an internal combustion engine as recited in claim 10 wherein said override control means includes walls defining a chamber, I

a piston means within said chamber,

air passage means for enabling air pressure communication between said chamber and said venturi passage for determining the position of said piston means responsive to said air pressure,

a cam means having a cam surface, and

means for moving said cam means surface against said throttle rod means responsive to motion of said piston means to establish maximum motion of said movable throttle rod means to limit hydrocarbon fuel flow to a predetermined maximum value for any given pressure in said venturi passage.

14. In an internal combustion engine, an induction system for providing a hydrogen rich gas, hydrocarbon fuel and air mixture to said engine to minimize the air pollutants produced by said engine comprising throttle controlled valve means for measuring the quantity of hydrocarbon fuel provided for said mixture, override control means for establishing the maximum amount of said hydrocarbon fuel provided by said throttle control means for said mixture consistant with an upper equivalence ratio of approximately 0.6 over the operating range of said engine,

pneumatic atomizer means for mixing hydrogen rich gas with the output of said throttle controlled means to provide a mixed fuel, throttle controlled air valve means for determining the amount of air mixed with said fuel mixture at a value which assures a combustible mixed fuel-air mixture under all operating conditionsincluding high speed, light load engine and operating conditions. 7

15. A method of minimizing the air pollution output of an internal combustion engine comprising the steps of over the operating range of sa-id engine mixing,

within said engine, induction system, air, hydrocarbon fuel and hydrogen rich gas,

controlling saidmixing to provide a fuel-air mixture ratio that is within the flammable range for the mixture and does not exceed a selected upper bound equivalence ratio of approximately 0.6, and

supplying said mixture to said engine.

16. A method as recited in claim 15 wherein said step of mixing said air, hydrocarbon fuel and hydrogen rich gas includes of supplying predetermined quantities of hydrocarbon fuel includes limiting the maximum amount of hydrocarbon fuel provided over the operating range of said engine responsive to the mass airflow to said engine.

18. A method as recited in claim 15 wherein said step of controlling said mixing provides only a mixture of a hydrogen rich gas and air when said engine is idling.

Claims

1. A system for minimizing the air pollution output of an internal combustion engine comprising an induction system for said engine having means for mixing a hydrogen rich gas, a liquid fuel and air; means for controlling said means for mixing over the operating range of said engine to provide a gas, fuel and air mixture in proportions within predetermined upper and lower equivalence ratio bounds and yet are within the flammable range of said mixture which minimize air pollution by said engine, and means for applying the output of said means for mixing to said internal combustion engine.

2. A system as recited in claim 1 wherein said means for mixing includes a pneumatic atomizer for atomizing fuel and mixing fuel with hydrogen rich gas, and air valve means for controlling the amount of air permitted to flow to said internal combustion engine together with said mixture of fuel and gas.

3. A system as recited in claim 2 wherein said means for controlling said means for mixing includes a throttle controlled fuel control valve means for controlling the amount of fuel supplied to said pneumatic atomizer; MEANS for sensing the mass air flow to said engine and producing a representative control effect, and override means responsive to said mass air flow control effect for limiting to a predetermined value the maximum amount of fuel supplied by said flow control valve to said pneumatic atomizer over the operating range of said engine.

4. A system as recited in claim 3, wherein said means for sensing the mass air flow to said engine and producing a representative control effect includes an induction tube for supplying air to the manifold of said engine, means for establishing a venturi in said induction tube, and means for measuring pressure variations of the air passing through said venturi and producing a control effect responsive thereto.

6. A system for minimizing the air pollution output of an internal combustion engine, comprising an induction system including walls defining an air induction tube, said induction tube being coupled to the manifold of said internal combustion engine, a fuel supply control system positioned within said induction tube and dimensioned to form an air venturi with the induction tube walls adjacent thereto, means for supplying hydrocarbon fuel to said fuel supply control system, means for supplying hydrogen rich gas to said fuel supply control system, valve means in said fuel supply control system for controlling the amount of hydrocarbon fuel permitted to pass through said fuel control system, said fuel supply control system further including means for mixing and emitting hydrocarbon fuel and hydrogen gas into said induction tube, override means responsive to air pressure caused by mass air flow through said venturi for limiting the amount of hydrocarbon fuel that can be passed through said fuel control system to a predetermined value, and throttle control means, operative in conjunction with said valve means for controlling the amount of air passing from said induction tube into said engine intake manifold to maintain a fuel-air mixture ratio which minimizes the air pollution output of said engine.

7. A system as recited in claim 6 wherein said means for mixing and emitting hydrocarbon fuel and hydrogen gas into said induction tube comprises a pneumatic atomizer, means for supplying hydrocarbon fuel from said valve means to said pneumatic atomizer, and means for supplying said hydrogen rich gas to said pneumatic atomizer as a working fluid to mix said hydrocarbon fuel as a fine mist with said gas.

8. A system as recited in claim 6 wherein said valve means in said fuel supply control means for controlling the amount of hydrocarbon fuel passing therethrough includes walls defining a substantially circular cavity, a fuel entrance passageway at one side of said cavity, a fuel exit passageway at another side of said cavity, and a rotatable throttle control cam means for establishing the size of the passageway through said circular cavity between said entrance passageway and said exit passageway from a blocked position when said engine is producing idle power requirements to a predetermined maximum opening which is correlated to engine speed.

9. A system as recited in claim 6 wherein said override means for limiting the maximum amount of fuel passed by said fuel supply control means includes walls defining a chamber, a piston within said chamber, air passage means for enabling air pressure communication between said chamber and said air venturi, for determining the position of said piston responsive to said air pressure, and means responsive to the position of said piston for preventing operation of said valvE means to increase the flow of hydrocarbon fuel through said fuel supply control system beyond a predetermined maximum amount as specified for each engine speed.

10. In an internal combustion engine a system for eliminating noxious emissions from said engine comprising a source of hydrocarbon fuel, a source of hydrogen rich gas, an induction system including an air intake induction tube, said tube containing throttle controlled fuel supply means, means establishing a venturi passage within the walls of said induction tubes, pipe means for bringing said hydrocarbon fuel and said hydrogen rich gas from said source of hydrocarbon fuel and said source of hydrogen to said throttle controlled fuel supply means, said throttle controlled fuel supply means including wall means forming a pneumatic atomizer for atomizing said hydrocarbon fuel and mixing it with said hydrogen rich gas to form a fuel mixture, override control means responsive to the pressure in said venturi passage established within said induction tube for limiting to a predetermined maximum amount for each specified engine speed the amount of hydrocarbon fuel supplied by said throttle controlled fuel supply means, means coupling said induction tube to said engine, and a throttle controlled means in said means coupling said induction tube to said engine for controlling the air supplied thereto to maintain the mixture ratio of the fuel mixture to air at all times within the flammable range of the fuel mixture to air and not to exceed an upper bound of approximately 0.6.

11. In an internal combustion engine as recited in claim 10 wherein said throttle controlled fuel supply means includes a variable area fuel control valve for supplying hydrocarbon fuel to said pneumatic atomizer, movable throttle rod means for controlling said variable area fuel control valve for determining the amount of hydrocarbon fuel flow to said pneumatic atomizer.

12. In an internal combustion engine as recited in claim 11 wherein said variable area fuel control valve includes means for closing off the hydrocarbon fuel supplied to said pneumatic atomizer when said movable throttle rod means assumes an engine idle position.

13. In an internal combustion engine as recited in claim 10 wherein said override control means includes walls defining a chamber, a piston means within said chamber, air passage means for enabling air pressure communication between said chamber and said venturi passage for determining the position of said piston means responsive to said air pressure, a cam means having a cam surface, and means for moving said cam means surface against said throttle rod means responsive to motion of said piston means to establish maximum motion of said movable throttle rod means to limit hydrocarbon fuel flow to a predetermined maximum value for any given pressure in said venturi passage.

14. In an internal combustion engine, an induction system for providing a hydrogen rich gas, hydrocarbon fuel and air mixture to said engine to minimize the air pollutants produced by said engine comprising throttle controlled valve means for measuring the quantity of hydrocarbon fuel provided for said mixture, override control means for establishing the maximum amount of said hydrocarbon fuel provided by said throttle control means for said mixture consistant with an upper equivalence ratio of approximately 0.6 over the operating range of said engine, pneumatic atomizer means for mixing hydrogen rich gas with the output of said throttle controlled means to provide a mixed fuel, throttle controlled air valve means for determining the amount of air mixed with said fuel mixture at a value which assures a combustible mixed fuel-air mixture under all operating conditions including high speed, light load engine and operating conditions.

15. A method of minimizing the air pollution output of an internal combustion engine comprising the steps of over the operating range of said engine mixing, within said engine induction system, air, hydrocarbon fuel and hydrogen rich gas, controlling said mixing to provide a fuel-air mixture ratio that is within the flammable range for the mixture and does not exceed a selected upper bound equivalence ratio of approximately 0.6, and supplying said mixture to said engine.

16. A method as recited in claim 15 wherein said step of mixing said air, hydrocarbon fuel and hydrogen rich gas includes supplying in predetermined quantities the amount of hydrocarbon fuel to be mixed with said hydrogen rich gas responsive to a throttle control, mixing said hydrocarbon fuel which is supplied with said hydrogen rich gas, mixing said mixture of hydrogen rich gas and hydrocarbon fuel with said air, and controlling the amount of air mixed to provide said fuel-air mixture ratio that is within the flammable range for the mixture and does not exceed a selected upper bound equivalance ratio of approximately 0.6.

17. A method as recited in claim 16 wherein said step of supplying predetermined quantities of hydrocarbon fuel includes limiting the maximum amount of hydrocarbon fuel provided over the operating range of said engine responsive to the mass air flow to said engine.