Opposed-piston internal combustion engine using hydrogen for initial combustion

Abstract

To improve thermal efficiency of an internal combustion engine.SOLUTION: An opposed-piston internal combustion engine includes an opposed piston mechanism in which an intake compression cylinder 1 and an expansion exhaust cylinder 2 are individually provided and a compressed air introduction valve 3 and an ignition combustion chamber 4 are configured therebetween. The opposed-piston internal combustion engine uses a fuel including hydrogen having excellent burning characteristic under a high-temperature and high-pressure environment, performs initial combustion in the ignition combustion chamber 4 and performs latter combustion with the expansion exhaust cylinder 2 by multistage fuel injection, thereby performing combustion under a higher temperature and pressure environment than that of existing internal combustion engines together with initial combustion and latter combustion.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to internal combustion engines. [Background technology]

[0002] To protect the global environment, it is necessary to transition from fossil fuels to carbon-free fuels for internal combustion engines, but carbon-free fuels are rare and expensive, so it is important to reduce fuel consumption, but in order to do so, it is necessary to improve the thermal efficiency of the engine. An effective means of achieving this is to develop combustion technology under higher temperature and pressure environments, but with conventional internal combustion engine technology, abnormal combustion such as knocking occurs in the early stages of combustion when combustion is performed under high temperature and pressure environments, which increases the possibility of engine damage, and this is an obstacle to reducing fuel consumption. Summary of the Invention [Problem to be solved by the invention]

[0003] In conventional internal combustion engines, the intake, compression, combustion, expansion, and exhaust processes are all performed in the same cylinder, and so the valve mechanism, spark plugs, fuel injectors, and other components required for each process are concentrated in the cylinder head that forms the combustion chamber, and because the combustion chamber shape is irregular, the ignition temperature is reached locally in high-temperature, high-pressure environments, causing abnormal combustion. In addition, the material properties of gasoline, diesel, alcohol, and other fuels currently used are not sufficient to withstand the above-mentioned local temperature rises, which is a factor in causing abnormal combustion in high-temperature, high-pressure environments compared to conventional internal combustion engines. [Means for solving the problem]

[0004] The basic configuration of the internal combustion engine is an opposed piston internal combustion engine with a high compression ratio cylinder 1 for intake compression and cylinder 2 for expansion and exhaust arranged in parallel, with a compressed air introduction valve 3 for introducing and sealing compressed air between the intake compression cylinder 1 and the early expansion and exhaust cylinder 2, and an ignition combustion chamber 4. Furthermore, hydrogen, which has excellent physical properties for lean combustion and has excellent combustion performance even in high-temperature and high-pressure air, is used as the fuel for initial combustion.

[0005] Hydrogen, the fuel used in the initial combustion, is supplied from a hydrogen storage container 16 to a hydrogen supply device 17, which adjusts the hydrogen to a specified pressure, measures the amount of hydrogen with a hydrogen flow meter when necessary, and supplies it to a fuel injection device 10 installed in the ignition combustion chamber 4. The fuel injection device 10 injects a specified amount of hydrogen into the ignition combustion chamber 4 at a specified timing. The hydrogen injected into the ignition combustion chamber 4 is ignited by the high temperature of the compressed air and by a spark from an ignition plug 12 when necessary. The combustion speed of hydrogen is very fast, and the combustion gas generated in the initial combustion is quickly introduced into the expansion exhaust cylinder 2 from the combustion gas ejection holes 15.

[0006] The later combustion carried out in the expansion exhaust cylinder 2 uses hydrocarbon fuel supplied from a hydrocarbon fuel storage container 19. The hydrocarbon fuel is supplied from the hydrocarbon fuel storage container 19 to a hydrocarbon fuel supply device 20, which adjusts the pressure of the hydrocarbon fuel and supplies it to a multi-stage fuel injection device 11 installed in the expansion exhaust cylinder 2. The multi-stage fuel injection device 11 injects a predetermined amount of hydrocarbon fuel at a predetermined timing into the expansion exhaust cylinder 2 into which the combustion gas that has become high temperature and high pressure due to the initial combustion is introduced, and burns it to carry out later combustion. At the same time, unburned fuel and soot are burned in the later combustion.

[0007] The hydrogen storage container 16 must be highly strong to prevent rupture or damage from external impact, and therefore is heavy and expensive; however, an opposed-piston internal combustion engine having a fuel reformer 21, as described below, produces reformed fuel containing hydrogen from hydrocarbon fuel through a chemical reaction in a hydrocarbon reforming catalyst, so that hydrogen can be introduced as engine fuel without installing the hydrogen storage container 16.

[0008] The features of the intake compression cylinder 1, exhaust expansion cylinder 2, and compressed air introduction valve 3 of the opposed piston internal combustion engine with a fuel reformer are the same as those described in

[0004] . A fuel reformer 21 is installed in an exhaust manifold 26, and the fuel reformer 21 incorporates an exhaust gas purification device 22 and a fuel reforming chamber 23 installed so as to surround the exhaust gas purification device 22, and the temperature inside the fuel reformer 21 is raised to a temperature required for the fuel reforming reaction by heat from the exhaust gas purification device 22. The fuel reformer 21 also has a cooling device for adjusting the internal temperature when necessary. A hydrocarbon reforming catalyst that reforms hydrocarbon fuel to produce reformed fuel containing hydrogen is installed inside the fuel reforming chamber 23, and the reformed fuel containing hydrogen produced by reforming the hydrocarbon fuel supplied from the hydrocarbon fuel supply device 20 is supplied to the reformed fuel supply device 24. The reformed fuel supplying device 24 adjusts the pressure of the reformed fuel containing hydrogen and supplies the reformed fuel containing hydrogen to a hydrogen flow rate measuring device 25, the hydrogen flow rate measuring device 25 measures the amount of hydrogen in the reformed fuel containing hydrogen and reflects the amount in engine control, and supplies the reformed fuel containing hydrogen to a fuel injection device 30 installed in the ignition combustion chamber 4. The ignition combustion chamber 4 also has a fuel injection device 31 that injects hydrocarbon fuel, and the hydrocarbon fuel injected by the fuel injection device 31 is supplied from a hydrocarbon storage container 19 to a hydrocarbon supplying device 20, and the hydrocarbon supplying device 20 adjusts the hydrocarbon fuel to a predetermined pressure and supplies it to the fuel injection device 31, so that the reformed fuel containing hydrogen injected by the fuel injection device 30 and the hydrocarbon fuel injected by the fuel injection device 31 are combusted in the ignition combustion chamber 4 in a predetermined amount and ratio, thereby performing initial combustion. The initial combustion proceeds quickly due to the characteristics of hydrogen, and the high-temperature, high-pressure combustion gas is introduced into the expansion and exhaust cylinder 2 through the combustion gas nozzle 15. In the latter combustion, the hydrogen-containing reformed fuel generated by the fuel reformer 21 is also used, and the hydrogen-containing reformed fuel is supplied from the fuel reformer 21 to the reformed fuel supply device 27, which adjusts the pressure of the hydrogen-containing reformed fuel and supplies the hydrogen-containing reformed fuel to the hydrogen flow rate measurement device 28, which measures the hydrogen flow rate in the hydrogen-containing reformed fuel and reflects it in engine control, and supplies the hydrogen-containing reformed fuel to the multistage fuel injection device 29. In addition, a multistage fuel injection device 32 that injects hydrocarbon fuel is installed in the expansion and exhaust cylinder 2, and the hydrocarbon fuel injected by the multistage fuel injection device 32 is supplied from the hydrocarbon fuel storage container 19 to the hydrocarbon fuel supply device 20, which adjusts the hydrocarbon fuel to a predetermined pressure and supplies it to the multistage fuel injection device 32. The hydrogen-containing reformed fuel from the multistage fuel injection device 29 and the hydrocarbon fuel from the multistage fuel injection device 32 are injected into the expansion and exhaust cylinder 2 at a predetermined amount and timing, and combusted, to perform the latter combustion. At the same time, the post-combustion also burns unburned fuel and soot in the combustion gas. Effect of the Invention

[0009] In opposed piston engines, the combustion gas in one cylinder is expanded by two pistons and converted into power, so the energy of the combustion gas is recovered as power with high efficiency. In addition, since the ignition combustion chamber 4 is installed separately from the intake and exhaust valve mechanism parts, there are few restrictions on the combustion chamber shape and material, and it is possible to use an optimal shape and highly heat-resistant material for combustion, making it possible to burn in a higher temperature and pressure environment. Furthermore, by using hydrogen, which has excellent combustion performance even in a high temperature and pressure environment, as the initial combustion fuel, abnormal combustion in a high temperature and pressure environment is reduced. As a result of the above effects, combustion in a high temperature and pressure environment that was not possible with conventional internal combustion engines is performed, improving thermal efficiency and reducing fuel consumption.

[0010] The fuel, hydrogen, can be produced by electrolysis of water, making it possible to use a fuel that does not rely on fossil fuels.

[0011] The reduced fuel consumption effect will result in reduced costs and consumption of expensive and scarce carbon-free hydrocarbon fuels such as biomass fuels and synthetic fuels. [Brief description of the drawings]

[0012] [Figure 1] This is a conceptual diagram of the mechanical layout of an internal combustion engine in which the intake compression cylinder 1 and the expansion and exhaust cylinder 2 used in the present invention are installed separately. The diagram is with the central axis of the cylinder vertical. The crank angle is at the top dead center of the piston, the compressed air introduction valve 3 is open, and the air compressed in the intake compression cylinder 2 is introduced into the ignition combustion chamber 4 through the hole of the compressed air introduction valve 3. [Diagram 2] This is a cross-sectional view taken along the line A-A in Figure 1, showing an embodiment of an engine that uses hydrogen for initial combustion. Air compressed in an intake compression cylinder 1 is being introduced into an ignition combustion chamber 4 through a compressed air introduction valve 3. The flow of fuel is indicated by black arrows. [Diagram 3] This is a cross-sectional view taken along line A-A in Fig. 1 of an embodiment of an engine having a hydrocarbon reformer. Air compressed in an intake compression cylinder 1 is introduced into an ignition combustion chamber 4 through a compressed air inlet valve 3. A fuel reformer 21, a reformed fuel supply device 24, a reformed fuel supply device 27, a hydrogen flow rate detector 25, and a hydrogen flow rate detector 28 are installed. The flow of fuel is indicated by black arrows. [Figure 4] This is a cross-sectional view taken along the line A-A in Figure 1, showing the initial combustion state of an engine using hydrogen fuel as the initial fuel. The compressed air introduction valve 3 is closed, the fuel injector 10 is injecting hydrogen fuel, and the spark plug 12 is operating. The black arrows indicate the flow of combustion gas. In an engine having a fuel reformer 21, in this state, reformed gas fuel containing hydrogen is injected from the fuel injector 30, and hydrocarbon fuel is injected from the fuel injector 31 into the ignition combustion chamber 4. Fuel supply-related equipment has been omitted to make it easier to understand the operation of the engine. [Diagram 5]A cross-sectional view taken along line A-A in Fig. 1 in a later combustion state of an engine using hydrogen fuel as the initial fuel. A cross-sectional view taken along line A-A in Fig. 1 when the multi-stage fuel injector 11 is injecting hydrocarbon fuel into the expansion exhaust cylinder 2. The black arrow represents the injected fuel, and the white arrow represents the intake air. In an engine having a fuel reformer 21, in this state, reformed gas fuel containing hydrogen is injected from the fuel injector 29, and hydrocarbon fuel is injected from the fuel injector 32 into the expansion exhaust cylinder 2. Fuel supply-related equipment has been omitted to make it easier to understand the operation of the engine. [Figure 6] A cross-sectional view of the A-A section in Figure 1 in the exhaust state after combustion has ended. The white arrow indicates the exhaust. The intake compression cylinder 1 compresses the newly taken in air. Fuel supply-related equipment has been omitted to make it easier to understand the operation of the engine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention can be implemented in internal combustion engines such as automobiles and generators. EXAMPLES

[0014] An embodiment is shown in Figures 2 and 3. The hydrogen storage container 16 is similar to that already in use in fuel cell vehicles. The hydrocarbon fuel storage container 19 is similar to a fuel tank mounted on equipment having an internal combustion engine. The fuel reformer 21 is installed in the same manner as an exhaust purification device of a conventional internal combustion engine. [Explanation of symbols]

[0015] 1. Intake and compression cylinder 2. Expansion and exhaust cylinder 3 Compressed air introduction valve 4 Ignition combustion chamber 5 pistons 6 pistons 7 Crank 8 Crank 9 Connecting rod 10 Fuel injector 11 Multi-stage fuel injection system 12 Spark plug 13 Intake valve 14 Exhaust valve 15 Combustion gas outlet 16 Hydrogen storage container 17 Hydrogen supply device 18 Hydrogen flow measurement device 19 Hydrocarbon fuel storage container 20 Hydrocarbon fuel supply device 21 Fuel reformer 22 Exhaust gas purification device 23 Fuel reforming chamber 24 Reformed fuel supply device 25 Hydrogen flow measurement device 26 Exhaust manifold 27 Reformed fuel supply device 28 Hydrogen flow rate detection device 29 Multi-stage fuel injection device 30 Fuel injection device 31 Fuel injection device 32 Multistage fuel injection device

Claims

1. The opposed piston internal combustion engine has an intake compression cylinder 1 and an expansion and exhaust cylinder 2, and an ignition combustion chamber 4 between the intake compression cylinder 1 and the early expansion and exhaust cylinder 2, and hydrogen is used as fuel for initial combustion, the hydrogen is supplied from a hydrogen storage container 16 to a hydrogen supply device 17, the hydrogen supply device 17 adjusts the hydrogen to a predetermined pressure and supplies it to a hydrogen flow rate detection device 18, the hydrogen flow rate detection device 18 detects the hydrogen flow rate and supplies hydrogen to a fuel injection device 10 installed in the ignition combustion chamber 4, the fuel injection device 10 injects a predetermined amount of hydrogen into the ignition combustion chamber 4 to perform initial combustion, and hydrogen generated by the initial combustion is supplied to the hydrogen supply device 17. An opposed-piston internal combustion engine using hydrogen for initial combustion, characterized in that combustion gas is introduced from a combustion gas ejection hole 15 into an expansion exhaust cylinder 2 where late combustion takes place, hydrocarbon fuel is used as fuel for the late combustion, the hydrocarbon fuel is supplied from a hydrocarbon fuel storage container 19 to a hydrocarbon supply device 20, the hydrocarbon fuel supply device 20 adjusts the hydrocarbon fuel to a predetermined pressure and supplies it to a multi-stage fuel injection device 11 attached to the expansion exhaust cylinder 2, thereby combusting the hydrocarbon fuel injected by the multi-stage fuel injection device 11 in the expansion exhaust cylinder 2 at a predetermined amount and timing, thereby performing late combustion.

2. The opposed piston internal combustion engine has an intake compression cylinder 1, an expansion and exhaust cylinder 2, and an ignition combustion chamber 4 and a fuel reformer 21 in which two fuel injection devices 30 and 31 that supply different fuels are installed between the intake compression cylinder 1 and the expansion and exhaust cylinder 2, the fuel reformer 21 has an exhaust gas purification device 22 and a fuel reforming chamber 23 therein, the fuel reforming chamber 23 has a hydrocarbon reforming catalyst that produces hydrogen from a hydrocarbon fuel, an inlet for the hydrocarbon fuel, and an outlet for discharging the reformed fuel containing the produced hydrogen, The reformer 21 supplies reformed fuel containing hydrogen produced by the hydrocarbon reforming catalyst to the reformed fuel supply device 24 and the reformed fuel supply device 27. The reformed fuel supply device 24 adjusts the pressure of the reformed fuel containing hydrogen to a predetermined pressure and supplies it to the hydrogen flow rate detection device 25. The hydrogen flow rate detection device 25 detects the hydrogen flow rate and supplies the reformed fuel containing hydrogen to the fuel injection device 30 installed in the ignition combustion chamber 4. A fuel injection device 31 is also installed to inject hydrocarbon fuel into the ignition combustion chamber 4. The hydrocarbon fuel injected by the fuel injection device 31 is extracted from the hydrocarbon fuel storage container 19 and supplied to the reformed fuel supply device 24. The hydrocarbon supply device 20 adjusts the hydrocarbon fuel to a predetermined pressure and supplies it to the fuel injection device 31, whereby the reformed fuel containing hydrogen injected by the fuel injection device 30 and the hydrocarbon fuel injected by the fuel injection device 31 are combusted in a predetermined amount in the ignition combustion chamber 4 to perform initial combustion, and the combustion gas generated by the initial combustion is introduced from the combustion gas ejection hole 15 into the expansion exhaust cylinder 2 where the latter combustion is performed, and the reformed fuel supply device 27 adjusts the pressure of the reformed fuel containing hydrogen supplied from the fuel reformer 21 to a predetermined pressure and detects the hydrogen flow rate. The hydrogen flow rate detection device 28 detects the hydrogen flow rate in the hydrogen-containing reformed fuel and supplies the hydrogen-containing reformed fuel to a multi-stage fuel injection device 29 attached to the expansion exhaust cylinder 2. A multi-stage fuel injection device 32 that injects hydrocarbon fuel is installed in the expansion exhaust cylinder 2. The hydrocarbon fuel injected by the multi-stage fuel injection device 32 is supplied from a hydrocarbon fuel storage container 19 to a hydrocarbon fuel supply device 20. The hydrocarbon fuel supply device 20 adjusts the hydrocarbon fuel to a predetermined pressure and supplies it to the multi-stage fuel injection device 32.An opposed piston internal combustion engine using hydrogen for initial combustion, characterized in that a reformed fuel containing hydrogen injected from a multi-stage fuel injection device 29 and a hydrocarbon fuel injected from a multi-stage fuel injection device 32 are combusted in a predetermined amount and timing in the expansion and exhaust cylinder 2 to perform late combustion.

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