GB1563453A

GB1563453A - Method of and apparatus for supplying gaseous fuel to internal combustion engines

Info

Publication number: GB1563453A
Application number: GB45642/77A
Authority: GB
Original assignee: INST MASHINOSTR AKAD NAUK UKRA
Current assignee: INST MASHINOSTR AKAD NAUK UKRA
Priority date: 1977-11-02
Filing date: 1977-11-02
Publication date: 1980-03-26

Description

(54) A METHOD OF AND APPARATUS FOR SUPPLYING GASEOUS FUEL TO INTERNAL COMBUSTION ENGINES (71) We, INSTITUT PROBLEM MASHINO STROENIA AKADEMII NAUK UKRAINSKOI SSR, of ulitsa Krasnoznamennaya 4, Kharkov, USSR, a USSR coporate body, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of and apparatus for supplying gaseous fuel to internal combustion engines.

The present invention can be used successfully for the internal combustion engines of transport vehicles such as truck tractors, motor buses, motor trucks and passenger cars running on hydrogen fuel produced directly on the vehicle.

Acute importance nowadays is attached to the problem of protecting the environment against pollution of the atmosphere. It is widely known, for example, that in the USA half of the total pollution of the atmosphere with carbon monoxide, nitrogen oxides, hydrocarbons and other toxic agents is attributable to motor vehicles; in the Federal Republic of Germany the proportion of atmospheric pollution attributable to motor vehicles amounts to 50(re though they consume only 12% of the fuel used in that country: in Japan the air pollution has risen above the toxicity standards, which has led to the necessity of improving internal combustion gas engines running on hydrogen fuel. The hydrogen engine is ecologically pure since it does not pollute the atmosphere with exhaust products harmful to man.The products exhausted by the hydrogen engine are water steam and unbound nitrogen.

Moreover, the use of hydrogen as a fuel for internal combustion engines solves one more problem, that of providing substitutes for costly hydrocarbon fuels of which the reserves on the earth are finite and irreproducible and which, therefore, are apt to grow ever more expensive.

Hydrogen fuel has no tendency towards becoming more expensive because it may be obtained from materials, for example, from silicon and water, which are not only effectively inexhaustible but also may be constantly recycled, thus being practically nonexpendable.

The large-scale industrial utilization of internal combustion engines running on hydrogen fuel is basically handicapped by the difficulties involved in storage and transportation of hydrogen fuel on the transport vehicle. In view of the fact that the densitv of hydrogen under normal conditions is very low (0.089 kg/m3), the required large amounts of hydrogen fuel carried by the vehicle or, in other words, an increase in the calorific value per unit volume of the fuel container can be ensured by compressing the hydrogen to high pressures, which introduce fire and explosion hazards on the vehicle.

An object of the present invention is to ensure safety against explosion by controlling the evolution of hydrogen.

Another object of the present invention is to decrease the bulk of a hydrogen generator to a size acceptable for mounting on a transport vehicle while still ensuring the generation of hydrogen in the amount required for an internal combustion engine.

According to the present invention there is provided a method of supplying combustible gas to an internal combustion engine which consists in producing hydrogen in a generator by a reaction between water and an energy-accumulating agent as hereinbelow defined, controlling the amount of hydrogen required for engine operation by metering the amounts of water and energyaccumlulating agent supplied to the generator under the control of an accelerator pedal, mixing the hydrogen with air and delivering the hydrogen-air mixture into the engine combustion chamber. The term "energyaccumulating agent" is used herein to denote substances capable of reacting exothermically with water to yield hydrogen and of being obtained by a reduction reaction from the resulting oxides or hydrides.

This method of fuel supply permits the hydrogen to be evolved and supplied to a combustion chamber of the engine in the amounts required for engine operation at a preset load without accumulating reserve quantities of hydrogen on the automobile.

This reduces fire and explosion hazards.

It is desirable that during the reaction between the energy-accumulating agent and water the amount of water is larger than is stoichiometrically necessary. This is advantageous because the chemical reaction resulting in hydrogen evolution is accompanied by liberation of a great amount of heat which has to be removed from the hydrogen generator, since otherwise the temperature of reaction will rise above the limits of strength of the material of which the generator is constructed.

In addition, the presence of water vapour in hydrogen used as a fuel is known to exert a positive influence in producing a reduction of emission of oxides of nitrogen, because it produces a certain reduction of the combustion temperature in the engine from that resulting if dry hydrogen is used.

An amount of water exceeding several times the required stoichiometrical limit also improves the kinetics of the chemical reaction.

The preferred energy-accumulating agents are such elements as aluminium, boron, silicon or their powdered alloys.

The use of the powdered energy-accumulating agent improves the conditions of the chemical reaction of hydrogen evolution, increases the velocity of said reaction and facilitates the delivery of said substances into the reaction zone.

Said elements, especially silicon are relatively cheap elements and are practically inexhaustible on the earth.

The supply of water and energy-accumulating agent should be adjusted by the pressure of the generated hydrogen so as to suit the engine operating load.

Thus a spontaneous rise of hydrogen pressure in the supply line from the hydrogen generator and communicating with the mixer is prevented by reducing the amount of reagents delivered into the hydrogen generator and eliminating sharp changes in hydrogen pressure caused by variations in engine performance.

The invention also provides a fuel system of an internal combustion gas engine comprising an induction pipe connected via a mixer with an air admission duct and a conduit delivering gas produced by the effect of water on an energy-accumulating agent said conduit communicating with the hydrogen generator, and an accelerator pedal arranged to control the amount of hydrogen required for engine operation which incorporates a water metering device communicating with the hydrogen generator and the engine water tank and linked with the accelerator pedal, and a device for metering the energy-accumulating agent, communicating with the hydrogen generator and the container for the energy-accumulating agent and linked with the accelerator pedal.

The water metering device is preferably in the form of a plunger pump equipped with a means for changing the plunger level.

The device for metering the energy-accumulating agent is conveniently in the form of a screw feed device provided with a means for changing its speed of rotation.

This arrangement of a fuel system of an internal combustion gas engine ensures efficient co-ordination of operation between the engine and the hydrogen generator, i.e.

it ensures the evolution in the generator of such an amount of hydrogen fuel which is necessary for engine operation at a preset duty without accumulating hydrogen reserves.

The use of a container holding an energyaccumulating agent makes it possible to reduce the bulk of the hydrogen generator and, in turn, decreases the metal content and weight of the fuel system and improves the conditions of its operation. This also simplifies the design of the generator.

It is recommended that the gas conduit should be in communication with a corrector connected with the accelerator pedal and with the devices for changing the speed of the feed screw and for changing the travel of the pump plunger.

Operation of the fuel system may be accompanied by certain changes in the operating conditions of the hydrogen generator caused by variations in the engine operating duties. This may lead to a sharp pressure rise in the hydrogen line and disturb the required air-hydrogen ratio in the fuel mix-ture. The introduction of a corrector into the engine fuel system prevents spontaneous rise of hydrogen pressure in the hydrogen line.

The fuel system may be provided with a throttle valve installed in the air induction pipe and fitted with a control element in the form of a pressure transmitter located in the hydrogen conduit.

This ensures the stoichiometrically necessary amount of air required for the combustion of the hydrogen, set automatically by the position of the throttle valve actuated by the pulse of the pressure transmitter and thus improves the conditions of combustion.

The present invention used in a city-service motor vehicle with a rated engine power of 75 hp ensures 50% of the rated operating power under urban conditions, the hydrogen consumption being 2.7 kg per 100 km.

Preferred features and advantages of the invention will become more apparent from the description of embodiments that follows, with reference to the accompanying drawings in which: Figure 1 is a schematic diagram of the fuel system of an internal combustion gas engine according to the invention; Figure 2 shows the fuel system according to the invention, with a corrector; Figure 3 shows the fuel system according to the invention, with a throttle valve.

The method of supplying hydrogen to an internal combustion engine, consists in producing hydrogen in a hydrogen generator 1 (Figure 1) by interaction of water with an energy-accumulating agent as hereinbefore defined, e.g. aluminium according to a reaction: 2A1 +3H2O=Al2O3+3H; in controlling the amount of hydrogen required for engine operation by the metered delivery of water and powdered aluminium under the control of an accelerator pedal 2 and then in directing the gas into a mixer 3 where it is mixed with air and from which the mixture of air with hydrogen is delivered into a combustion chamber 4 of the engine.

During interaction of the powdered aluminium with water the amount of water is maintained larger than stoichiometrically necessary in order to aid transference of heat from the gas generator, since heat is developed in great quantities as a result of the exothermic chemical reaction. Besides, the presence of water vapour in the hydrogen fuel reduces the emission of nitrogen oxides by producing a certain decrease of temperature in the engine combustion chamber 4. To prevent uncontrollable rise of pressure in the gas line, the delivery of the reagent is adjusted by the pressure of the evolved hydrogen.

This method as realized in an engine fuel system embodying the invention, which comprises a combustion chamber 4 communicating via a mixer 3 with an air induction pipe 5 and with a hydrogen delivery conduit 6 communicating with the hydrogen generator 1. The fuel supply system also incorporates a water metering device in the form of an axial plunger 7 including a means for changing the travel of the plunger 8 and a device for metering the powdered aluminum in the form of a feed screw 9 provided with a means for changing its speed of rotation. The pump 7 communicates through a pipe 10 with a water tank 11 and, through a pipe 10a, with the hydrogen generator 1.

The means for changing the travel of the plunger 8 is made in the form of a swashplate 12 coupled to drive the plunger 8 and linked by way of rods 13 and 14 with the accelerator pedal 2 by which the swash angle is thus controlled. The device for metering the powdered aluminium communicates through a pipe 15 with the hydrogen generator 1 and, through a pipe 15a, with a container 16 holding finely powdered aluminium. The means for changing the speed of the feed screw 9 is a variable speed drive 17 connected with the feed screw 9 and linked by way of rods 18, 19, 20 and 14 with the accelerator pedal 2. The hydrogen generator 1 is provided with a container 21 for collecting the aluminium oxide produced in the reaction.

The above described fuel system of the internal combustion engine operates as follows. When the accelerator pedal 2 is not depressed, the swash-plate 12 of the plunger pump 7 occupies a position in which the pump supplies the hydrogen generator only with the amount of water required for engine operation at no-load speed and the capacity of the feed screw 9 set by the position of the rod 18 of the variable-speed drive 17 also corresponds to the amount of aluminium powder required for engine idling.

The pressure in the hydrogen generator 1 then corresponds to idling duty. Hydrogen flows through the pipe 6 into the mixer 3 where it is mixed with air and enters the combustion chamber 4.

As the accelerator pedal 2 is depressed, the rod 14 acts on the rod 13, increases the angle of the swash plate 12 and, consequently, the travel of the plunger 8 of the pump 7 and also, acting on the variable speed drive 17 via rods 20, 19, 18, increases the speed of the feed screw 9. The hydrogen generator begins receiving a larger amount of water from the water tank 11 in unit time and a larger amount of aluminium powder from the container 16 so that, due to the reaction between aluminium powder and water, the hydrogen generator produces a larger amount of hydrogen which flows through the gas conduit 6 into the mixer 3 where it is mixed with air drawn in though the induction pipe 5. The hydrogen-air mixture formed in this manner is delivered into the combustion chamber 4.

To prevent uncontrollable rise of pressure in the hydrogen line 6 of the fuel system accordng to a modified embodiment of the invention, shown in Figure 2, the hydrogen conduit 6 communicates through the line 22 with a compensator 23. This compensator is connected by rod 14 of pedal 2 of the accelerator and with the rod 13 which controls the angle of the swash plate 12 and with the rod 20 which acts through the rods 19 and 18 to transmis a signal to the variable-speed drive 17 and so to control the supply of powdered aluminium. If pressure in the line 6 rises excessively, the corrector 23 changes the length of the rod 14 so as to disconnect it from the pedal 2 of the accelerator.As a result, firstly, the angle of the swash plate 12 is reduced by the rod 13 and this reduces the amount of water supplied by the pump 7 into the hydrogen generator and, secondly, acting on the variable-speed drive 17 through the rods 20, 19, 18, the compensator reduces the speed of the feed screw 9 with a resultant reduction of the amount of aluminium powder supplied by the feed screw 9. In case of a pressure drop in the line 6 and, consequently, in the line 22, the compensator 23 also acts upon the rod 14 so as to increase the amount of reagents delivered into the hydrogen generator 1.

Another modification of the fuel system according to the invention, shown in Figure 3, is provided with a throttle valve 24 installed in the air induction pipe 5 and provided with a control element in the form of a pressure sensor 25 located in the hydrogen conduit 6. The line 26 communicating with the hydrogen line 6 and with the mixer 3 includes a flow restrictor 27 whose passage area can be increased or decreased to adjust the proportion of excess air in the mixture fed to the engine.

The amount of air entering the mixer 3 from the iduction pipe 5 is controlled by the throttle valve 28 which is actuated by the pressure sensor 25. An increase in the amount of hydrogen evolved in the generator 1 raises the pressure in the conduit 6, so that the mixer receives a larger amount of hydrogen. The increased hydrogen pressure in the line 6 is received by the pressure sensor 25 which opens the throttle valve 24 and the mixer 3 thus receives a larger amount of air while retaining the proportion of surplus air at the value set by the flow restrictor 27. This arrangement may also be included in the embodiment of Figure 1.

WHAT WE CLAIM IS:- 1. A method of supplying combustible gas to an internal combustion engine which consists in producing hydrogen in a generator by the reaction between water and an energy-accumulating agent, as hereinbefore defined, controlling the amount of hydrogen required for engine operation by metering the amounts of water and energyaccumulating agent supplied to the generator under the control of an accelerator pedal, mixing the hydrogen with air and delivering the hydrogen-air mixture into the engine combustion chamber.

2. A method according to claim 1 wherein during interaction of the energy-accumulating agent with water the amount of water in the generator is maintained greater than is stoichiometrically necessary.

3. A method according to claim 1 or 2 wherein the energy-accumulating agent is aluminium, boron or silicon or a powdered alloy thereof.

4. A method according to any one of claims 1 to 3 wherein the supply of water and energy-accumulating agent is corrected by a compensator responsive to the pressure of the generated hydrogen, in accordance with the load on the engine.

5. An internal combustion gas engine fuel system comprising an induction pipe communicating through a mixer with an air induction pipe and a conduit communicating with a gas generator in which hydrogen is produced by a reaction between water and an energy-accumulating agent, an accelerator pedal arranged to control the amount of hydrogen provided to the engine, a water metering device communicating with the hydrogen generator and the water tank and linked with the accelerator pedal, and a device for metering the supply of the energy-accumulating agent communication with the hydrogen generator and with a container for the energy-accumulating agent and linked with the accelerator pedal.

6. A fuel system according to claim 5 wherein the water metering device is a plunger pump provided with a means for changing the travel of the plunger.

7. A fuel system according to claim 5 wherein the device for metering the supply of the energy-accumulating agent is made in the form of a feed screw provided with a means for changing its speed of rotation.

8. A fuel system according to claims 5-7 wherein the hydrogen conduit communicates through a pipe with a compensator corrector which is coupled between the accelerator pedal on the one hand and the means for changing the travel of the pump plunger and the means for changing the speed of the feed screw on the other hand.

9. A fuel system according to any one of claims 5 to 8 incorporating a throttle valve installed in the air admission branch pipe and provided with a control element in the form of a pressure sensor connected to the gas conduit.

10. A method of supplying hydrogen as a fuel to an internal combustion engine ac

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Claims

**WARNING** start of CLMS field may overlap end of DESC **.

with the rod 20 which acts through the rods 19 and 18 to transmis a signal to the variable-speed drive 17 and so to control the supply of powdered aluminium. If pressure in the line 6 rises excessively, the corrector 23 changes the length of the rod 14 so as to disconnect it from the pedal 2 of the accelerator. As a result, firstly, the angle of the swash plate 12 is reduced by the rod

13 and this reduces the amount of water supplied by the pump 7 into the hydrogen generator and, secondly, acting on the variable-speed drive 17 through the rods 20, 19, 18, the compensator reduces the speed of the feed screw 9 with a resultant reduction of the amount of aluminium powder supplied by the feed screw 9.In case of a pressure drop in the line 6 and, consequently, in the line 22, the compensator 23 also acts upon the rod 14 so as to increase the amount of reagents delivered into the hydrogen generator 1.

Another modification of the fuel system according to the invention, shown in Figure 3, is provided with a throttle valve 24 installed in the air induction pipe 5 and provided with a control element in the form of a pressure sensor 25 located in the hydrogen conduit 6. The line 26 communicating with the hydrogen line 6 and with the mixer 3 includes a flow restrictor 27 whose passage area can be increased or decreased to adjust the proportion of excess air in the mixture fed to the engine.

The amount of air entering the mixer 3 from the iduction pipe 5 is controlled by the throttle valve 28 which is actuated by the pressure sensor 25. An increase in the amount of hydrogen evolved in the generator 1 raises the pressure in the conduit 6, so that the mixer receives a larger amount of hydrogen. The increased hydrogen pressure in the line 6 is received by the pressure sensor 25 which opens the throttle valve 24 and the mixer 3 thus receives a larger amount of air while retaining the proportion of surplus air at the value set by the flow restrictor 27. This arrangement may also be included in the embodiment of Figure 1.

WHAT WE CLAIM IS:- 1. A method of supplying combustible gas to an internal combustion engine which consists in producing hydrogen in a generator by the reaction between water and an energy-accumulating agent, as hereinbefore defined, controlling the amount of hydrogen required for engine operation by metering the amounts of water and energyaccumulating agent supplied to the generator under the control of an accelerator pedal, mixing the hydrogen with air and delivering the hydrogen-air mixture into the engine combustion chamber.
2. A method according to claim 1 wherein during interaction of the energy-accumulating agent with water the amount of water in the generator is maintained greater than is stoichiometrically necessary.
3. A method according to claim 1 or 2 wherein the energy-accumulating agent is aluminium, boron or silicon or a powdered alloy thereof.
4. A method according to any one of claims 1 to 3 wherein the supply of water and energy-accumulating agent is corrected by a compensator responsive to the pressure of the generated hydrogen, in accordance with the load on the engine.
5. An internal combustion gas engine fuel system comprising an induction pipe communicating through a mixer with an air induction pipe and a conduit communicating with a gas generator in which hydrogen is produced by a reaction between water and an energy-accumulating agent, an accelerator pedal arranged to control the amount of hydrogen provided to the engine, a water metering device communicating with the hydrogen generator and the water tank and linked with the accelerator pedal, and a device for metering the supply of the energy-accumulating agent communication with the hydrogen generator and with a container for the energy-accumulating agent and linked with the accelerator pedal.
6. A fuel system according to claim 5 wherein the water metering device is a plunger pump provided with a means for changing the travel of the plunger.
7. A fuel system according to claim 5 wherein the device for metering the supply of the energy-accumulating agent is made in the form of a feed screw provided with a means for changing its speed of rotation.
8. A fuel system according to claims 5-7 wherein the hydrogen conduit communicates through a pipe with a compensator corrector which is coupled between the accelerator pedal on the one hand and the means for changing the travel of the pump plunger and the means for changing the speed of the feed screw on the other hand.
9. A fuel system according to any one of claims 5 to 8 incorporating a throttle valve installed in the air admission branch pipe and provided with a control element in the form of a pressure sensor connected to the gas conduit.
10. A method of supplying hydrogen as a fuel to an internal combustion engine ac

cording to any one of claims 1-4 and substantially as herein described.
11. An internal combustion engine fuel system substantially as herein described with reference to Figure 1, 2 or 3 of the accompanying drawings.