Internal combustion engine operated on injected fuel supplemented with hydrogen

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supplying the heat for the endothermic reforming reac

INTERNAL COMBUSTON ENGINE OPERATED tion carried out in the reforming device 36. The heat ON INJECTED FUE SUPPLEMENTED WITH 36a is arranged to be supplied with the heat of the ex Y)ROGEN haust gases emitted from the combustion chamber 20. A pipe 37 connecting the reforming device 36 and the fuel

This invention relates to an internal combustion en tank 32 functions to return the liquid fuel still not re gine operated on an air-fuel mixture supplemented with formed to the fuel tank 32. The reforming device 36 is hydrogen gas. connected to a reformed gas accumulator 40 for accu It is an object of the present invention to provide an mulating the reformed gas admitted from the reforming improved internal combustion engine which enables 10 device. The accumulator 40 has a pressure responsive stable operation of the engine with lower emission level switch 42 which is arranged to stop the function of the of noxious gases. fuel pump 34 when the pressure within the accumulator Another object of the present invention is to provide 40 exceeds a predetermined level. The accumulator 40 an improved spark ignition internal combustion engine is connected through a check valve 44 to a normally by which combustion chambers are firstly supplied with 15 open valve 46 which is arranged to be closed when the a mixture of hydrogen gas and air and thereafter liquid engine 10 is stopped. The accumulator 40 is further fuel is injected to the generally central portion of each connected to an upstream portion of the valve 46 combustion chamber, whereby the air-fuel mixture through a normally closed valve 48 which is arranged within the combustion chamber is stratified to effec to open for allowing the reformed gas to flow during tively be burned to lower the emission levels of carbon 20 engine starting. The valve 46 is connected to a dia monoxide and unburned hydrocarbons. phragm actuating valve 50 which forms part of regulat Other objects and features of the improved internal ing means 52. The valve 50 is connected to a nozzle 53 combustion engine in accordance with the principle of or a hydrogen gas supply nozzle which opens into the the present invention will become more apparent from air-intake passage 22 in order to supply the reformed the following description taken in conjunction with the 25 gas to the stream of air flowing through the air-intake accompanying drawings in which: passage 22. The diaphragm assembly 50a of the valve 50 FIG. 1 is a schematical representation of a preferred is communicated with a venturi portion 54 of the air embodiment of an internal combustion engine in accor intake passage 22 and therefore the valve 50 is arranged dance with the principle of the present invention; to regulate the amount of the reformed gas supplied FIG. 2 is schematical representation showing a man- 30 through the nozzle 53 in response to the vacuum gener ner of operating the engine of FIG. 1; and ated at the venturi portion 54, in other words, the air FIG. 3 is schematical representation similar to FIG. amount supplied to the combustion chamber 20 through 2, but shows another manner of operating the engine of the air-intake passage 22.

FIG. 1. The internal combustion engine 10 is equipped with Referring now to FIG. 1, there is shown a preferred 35 fuel injecting means 56 comprising the fuel tank 32 embodiment in accordance with the principle of the containing the liquid fuel. The fuel tank 32 is connected present invention in which a spark-ignition internal to a fuel pump 58 which is in turn connected to a vari combustion engine of the four-cycle valve-in-head type able plunger pump 60. The variable plunger pump 60 is is designated by reference numeral 10. The engine 10 is arranged to supply the combustion chamber 20 with a multi-cylinder internal combustion engine, only one 40 variable amounts of the liquid fuel through a fuel injec cylinder 12 of which is shown in the vertical transverse tor 62 in response to the movement of the accelerator section. The cylinder 12 is formed in the body casting 64. The fuel injector 62 is disposed through the gener portion of the cylinder block 14. A piston 16 is recipro ally central portion of the cylinder head 18 and extends cally disposed in the cylinder 12 and is operatively into the combustion chamber 20. The injector 62 is connected by a connecting rod to a crank arm of a 45 oriented generally toward the central portion of the crankshaft (they are not shown). combustion chamber 20 to inject the liquid fuel admit Covering the upper portion of the cylinder 12 is a ted from the plunger pump 60 toward same. Disposed cylinder head structure 18 which is secured to the body adjacent to the fuel injector 62 and through the gener casting portion of the cylinder block 14 by bolts (not ally central portion of the cylinder head 18 is a spark shown). The cylinder head 18 cooperates with the 50 plug 66 or an igniter which functions to ignite a rela upper portion of the piston 16 to form a combustion tively rich air-fuel mixture formed at the central portion chamber 20 therebetween. The cylinder head 18 is of the combustion chamber 20 by mixing the liquid fuel formed with an air-intake passage 22 and an exhaust sprayed from the injector 62 with the air inducted passage 24 which are connected to the combustion through the air-intake passage 22, chambr 20 through an intake valve 26 and an exhaust 55 With the arrangement mentioned hereinbefore, when valve 28, respectively. The air-intake passage 22 is ar the engine 10 is started, the reformed gas containing ranged to supply atmospheric air therethrough to the hydrogen gas within the accumulator 40 is supplied combustion chamber 20, from the nozzle 52 into the air-intake passage 22 As seen, the internal combustion engine 10 is through the valves 46, 48 and 50. Then, the supplied equipped with a hydrogen gas supply means 30 which 60 reformed gas is mixed with the air passing through the comprises a fuel tank 32 containing liquid fuel therein or air-intake passage 22, in which the mixed gas is set at a a fuel source. The fuel tank 32 is connected to a fuel lean air-fuel (reformed gas) mixture. After engine start pump 34 for admitting the fuel from the fuel tank32 into ing or during normal engine operation, the heat ex a fuel reforming device 36 which forms part of hydro changer 36a works receiving heat from the exhaust gen gas source 38. The reforming device 36 is arranged 65 gases to operate the fuel reforming device 36. The re to generate reformed gas containing hydrogen gas by forming device 36 then generates the reformed gas and endothermic reforming reaction. The reforming device the reformed gas is admitted to the accumulator 40. The 36 is equipped with a heater 36a or a heat exchanger for reformed gas is thereafter supplied through the valves

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44, 46 and 50 from the nozzle 52 into the air-intake even if the air-fuel mixture is as a whole over lean, and passage 22 to mix with the air passing through the air thermal efficiency of the engine is as a matter of course intake passage 22. improved. In addition, since the air-fuel mixture adja FIG. 2 illustrates a manner of operation of the engine cent the inner wall surface of the combustion chamber 10 constructed in accordance with the present inven contains hydrogen gas, the air-fuel mixture is effectively tion, at position (a) of which the mixed gas of reformed burned to prevent the incomplete combustion and ac gas and air in the air-intake passage 22 is thereafter cordingly the emission levels of carbon monoxide and . sucked and supplied through the intake valve 26 into unburned hydrocarbons are lowered to a considerable the combustion chamber 20 by descent of the piston 16 extent, or during suction or induction stroke of the engine 10. 10 What is claimed is:

At position (b), the liquid fuel is injected or sprayed 1. A method of operating an internal combustion from the injector 62 to the generally central portion of engine having a combustion chamber, comprising the the combustion chamber 20 during the compression steps in the following order of:

stroke. In this state, the relatively rich air-fuel mixture supplying a mixture of air and hydrogen gas into the containing hydrogen gas is formed at the generally 15 combustion chamber;

central portion of the combustion chamber 20 and a igniting the mixture in the combustion chamber; and layer of relatively lean air-fuel mixture containing hy supplying a sprayed liquid fuel into the combustion drogen gas is formed around the rich air-fuel mixture. chamber to be burned with the mixture. At position (c), the mixture compressed by the piston 16 2. A method as claimed in claim 1, in which the step is then ignited by the spark plug 66, in which the spark 20 of supplying a mixture includes a step of supplying the plug 66 ignites the rich air-fuel mixture at the central hydrogen gas into the stream of the air directed into the portion of the combustion chamber 20 to secure the combustion chamber.

ignition of the entire air-fuel mixture. At position (d), combustion spreads to the layer of lean air-fuel mixture of3.supplying

A method as claimed in claim 1, in which the step a sprayed fuel is included a step of inject surrounding the rich air-fuel mixture and then the gas 25 ing the fuel directly into the combustion chamber. within the combustion chamber expands to cause the piston to descend. It should be noted that the layer of of supplying the hydrogeningasclaim 4. A method as claimed 2, in which the step includes a step of regu the mixed gas containing hydrogen gas is adjacent the lating the supply amount of hydrogen gas in response to inner wall of the combustion chamber 20 and accord ingly the layer is effectively combusted through the 30 the5.air amount directed to the combustion chamber. An internal combustion engine having a cylinder, a layer is of the lean air-fuel mixture. This prevents imper cylinder head and a piston reciprocally disposed in the fect combustion of the lean mixture adjacent the inner cylinder to define a combustion chamber between the wall surface of the combustion chamber due to the low calorific value of the lean mixture and release or absorp cylinder head, comprising:

tion of heat generated by the combustion through the 35 an air-intake passage fluidly connected to the com wall of the combustion chamber. Therefore formation bustion chamber to supply air therethrough to the of the mixture layer containing hydrogen gas at the combustion chamber;

portion adjacent the inner wall of the combustion cham hydrogen gas supply means for supplying hydrogen ber noticeably contributes to lowering emission levels gas into said air-intake passage in response to the of carbon monoxide and unburned hydrocarbons. amount of the air supplied to the combustion cham FIG. 3 illustrates another manner of operation of the ber, said hydrogen gas supply means including engine 10 which is similar to that of FIG. 2 with the a hydrogen gas source, said hydrogen gas source exception that the liquid fuel is injected from the fuel including a fuel source containing a liquid fuel injector 62 after the mixed gas of reformed gas and air therein, a fuel pump connected to said fuel source, is ignited by the spark plug 66. As shown at position (b), 45 a fuel reforming device connected to said fuel the mixed gas containing hydrogen gas is ignited at a pump and arranged to generate the reformed gas timing before top dead center. The ignition timing is containing hydrogen gas, a reformed gas accumu preferably about 10" before top dead center. At position lator connected to said reforming device for accu (c), the liquid fuel is injected and sprayed into the com mulating the reformed gas admitted from the re bustion chamber 20 to be ignited with the flame pro SO forming device, a pressure responsive switch ar duced by the combustion of the mixed gas. ranged to stop the function of said fuel pump when While the fuel reforming device 36 and its accessories the pressure within the accumulator exceeds a pre are shown and described as a hydrogen gas source, it determined level, a check valve connected to the will be seen that a cylinder containing hydrogen gas accumulator, a normally open valve connected to may be used for the same purpose. 55 said check valve and arranged to close for blocking It will be understood that the engine according to the the reformed gas to flow when the engine is present invention is, through not shown, equipped with stopped, and a normally closed valve connecting means for setting the spark-ignition timing of the spark the accumulator and the upstream portion of said plug 66 after the fuel injection timing of the injector 62 normally open valve, and arranged to open for when operated in the manner shown in FIG. 2, whereas 60 allowing the reformed gas to flow during engine with means for setting the timing of the spark-plug 66 starting, before the timing of the injector 62 when operated in regulating means connected to said hydrogen gas the manner shown in FIG, 3. source for regulating the hydrogen gas flowing As is apparent from the foregoing discussion, with amount in response to the air amount supplied to the internal combustion engine in accordance with the 65 the combustion chamber, and present invention, the stratified charge of the air-fuel a hydrogen gas supply nozzle connected to said regu mixture is achieved and therefore ignition and combus lating means and opening into said air-intake pas tion of the air-fuel mixture are effectively carried out Sage;

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fuel injecting means for injecting liquid fuel to the ranged to be supplied with heat of the exhaust gas central portion of the combustion chamber to form emitted from the combustion chamber, a reformed a rich air-fuel mixture at the generally central por gas accumulator connected to said reforming de tion of the combustion chamber; and vice for accumulating the reformed gas admitted an igniter disposed through the generally central from the reforming device, a pressure responsive portion of the cylinder head to ignite the rich air switch arranged to stop the function of said fuel fuel mixture at the generally central portion of the pump when the pressure within the accumulator combustion chamber. exceeds a predetermined level, a check valve con 6. An internal combustion engine as claimed in claim nected to the accumulator, a normally open valve 5, in which said regulating means includes a venturi 10 connected to said check valve and arranged to portion formed at said air-intake passage, and a dia close for blocking the reformed gas to flow when phragm actuating valve connected to said normally the engine is stopped, and a normally closed valve open valve and arranged to open for allowing the re connecting the accumulator and the upstream por formed gas to flow in response to the vacuum generated tion of said normally open valve, and arranged to at said venturi portion, said diaphragm actuating valve 15 open for allowing the reformed gas to flow during being connected to said hydrogen gas supply nozzle. engine starting, regulating means connected to said 7. An internal combustion engine as claimed in claim hydrogen gas source for regulating the hydrogen 5, in which said fuel reforming device is equipped with gas flowing amount in response to the air amount a heater for supplying the heat for endothermic reform supplied to the combustion chamber, said regulat ing reaction carried out in the reforming device, said 20 ing means including a venturi portion formed at heater being arranged to be supplied with heat of the said air-intake passage, and a diaphragm actuating exhaust gas emitted from the combustion chamber. valve connected to said normally open valve and 8. An internal combustion engine as claimed in claim arranged to open for allowing the reformed gas to 5, in which said hydrogen gas source includes a cylinder flow in response to the vacuum generated at said containing hydrogen gas. 25 venturi portion, said diaphragm actuating valve 9. An internal combustion engine as claimed in claim being connected to said hydrogen gas supply noz 5, in which said fuel injecting means includes a fuel zle, and a hydrogen gas supply nozzle connected to source containing a liquid fuel therein, a fuel pump said regulating means and opening into said air connected to said fuel source, a fuel injector disposed 30 intake passage;

through the generally central portion of the cylinder fuel injecting means for injecting liquid fuel to the head, said fuel injector being oriented to the generally central portion of the combustion chamber to form central portion of the combustion chamber, and a vari a rich air-fuel mixture at the generally central por able plunger pump connecting said fuel pump and said tion of the combustion chamber, said fuel injecting fuel injector and arranged to supply the combustion means including a fuel source containing a liquid chamber with a variable amount of the liquid fuel fuel therein, a fuel pump connected to said fuel through said fuel injector in response to the movement source, a fuel injector disposed through the gener of an accelerator. ally central portion of the cylinder head, said fuel 10. An internal combustion engine having a cylinder, injector being oriented to the generally central a cylinder head and a piston reciprocally disposed in the portion of the combustion chamber, and a variable cylinder to define a combustion chamber between the plunger pump connecting said fuel pump and said cylinder head, comprising: fuel injector and arranged to supply the combus an air-intake passage fluidly connected to the com tion chamber with a variable amount of the liquid bustion chamber to supply air therethrough to the fuel through said fuel injector in response to the combustion chamber; movement of an accelerator; and hydrogen gas supply means for supplying hydrogen an igniter disposed through the generally central gas into said air-intake passage in response to the portion of the cylinder head to ignite the rich air amount of the air supplied to the combustion cham fuel mixture at the generally central portion of the ber, said hydrogen gas supply means including a combustion chamber.

hydrogen gas source, said hydrogen gas source 11. An internal combustion engine as claimed in claim including a fuel source containing a liquid fuel 50 10, in which further comprising means for setting the therein, a fuel pump connected to said fuel source, ignition timing of said igniter before the fuel injection a fuel reforming device connected to said fuel timing of said fuel injecting means, pump and arranged to generate the reformed gas 12, An internal combustion engine as claimed in claim containing hydrogen gas, said fuel reforming de 10, in which further comprising means for setting the vice being equipped with a heater for supplying the 55 ignition timing of said igniter after the fuel injection heat for endothermic reforming reaction carried timing of said fuel injecting means.

out in the reforming device, said heater being ar