WO2013001558A1

WO2013001558A1 - Engine system

Info

Publication number: WO2013001558A1
Application number: PCT/JP2011/003640
Authority: WO
Inventors: 島田　敦史; 石川　敬郎
Original assignee: 株式会社日立製作所
Priority date: 2011-06-27
Filing date: 2011-06-27
Publication date: 2013-01-03
Also published as: JP5696215B2; JPWO2013001558A1

Abstract

The purpose of the invention is to provide an engine system which can highly efficiently convert hydrogen generated from organic hydride to power. The engine system is provided with: an engine (11); a reactor (12) which generates hydrogen-rich gas from organic hydride using the heat of the exhaust gas from the engine (11); a hydrogen injector (16) which supplies the hydrogen-rich gas generated in the reactor (12) to the engine (11); a fuel injector (17) which supplies hydrocarbon fuel to the engine (11); an air flow regulation apparatus (18) provided in an intake pipe (29) of the engine (11); and a controller (19) (control means) which electronically controls the system. The engine system is characterized by controlling the combustion rate by regulating the air flow intensity according to the proportion of hydrogen in the fuel. DRAWING: FIG. 1: 19 Controller AA Air 11 Engine 12 Reactor　

Description

Engine system

The present invention relates to an engine system using hydrogen as a part of fuel.

Organic hydride can be used for energy storage such as natural energy, surplus power, and by-product hydrogen. Since organic hydride is a liquid fuel at normal temperature and pressure, it can store hydrogen at high density. System efficiency is improved by efficiently converting hydrogen generated from organic hydride into engine power using engine exhaust heat.

For example, a system described in Patent Document 1 is known as an engine system that uses hydrogen generated from organic hydride by utilizing such engine exhaust heat and dehydrogenated fuel as fuel.

JP 2006-312910 A

Since hydrogen has a higher combustion speed than other hydrocarbon fuels, it is necessary to control the combustion speed of the engine according to the proportion of hydrogen supplied to the engine. This is because as the combustion rate increases, the cooling loss of the engine increases and the thermal efficiency decreases. In particular, in the case of a high load condition, high compression ratio engine, the amount of change in the combustion speed due to the change in the hydrogen mixing ratio is further increased, and the problem of reduced thermal efficiency becomes significant.

In the engine system described in Patent Document 1, although the purpose is different, it is described that the air-fuel mixture is made leaner when the hydrogen addition ratio of the fuel supplied to the engine increases. The combustion speed can also be adjusted by changing the excess air ratio as in Patent Document 1. However, on the other hand, since the combustion temperature changes greatly by changing the excess air ratio, the exhaust temperature of the exhaust gas supplied to the reactor (hydrogen generator) installed in the exhaust pipe also changes. As a result, the amount of hydrogen produced in the reactor changes, making it difficult to keep the system efficiency stable.

An object of the present invention is to provide an engine system capable of converting hydrogen generated from organic hydride into power with high efficiency.

In response to the above problems, the present invention is characterized in that an air flow is formed in the cylinder during intake of the engine, and the combustion speed in the engine is controlled by adjusting the strength of the air flow.

That is, an engine system using hydrogen as a part of fuel according to the present invention includes an engine that generates power by burning hydrogen and a hydrocarbon-based fuel, and heat from the exhaust gas of the engine. A reactor having a catalyst for producing hydrogen and dehydrogenated fuel by a dehydrogenation reaction, a hydrogen supply means for supplying a hydrogen-rich gas generated in the reactor to an engine, and an air flow for adjusting a flow of air to be supplied to the engine An adjustment device; and a control means for controlling the operation of the air flow adjustment device, wherein the control means controls the air flow adjustment device in accordance with a ratio of hydrogen in the fuel supplied to the engine. It is characterized by.

In the control of the combustion speed by adjusting the flow strength according to the present invention, the fluctuation of the exhaust temperature is small compared to the case of controlling the excess air ratio. Therefore, the combustion speed of the engine can be adjusted without significantly affecting the amount of hydrogen generated by the hydrogen generator, and as a result, the system efficiency can be improved.

According to the present invention, an engine system capable of converting hydrogen generated from organic hydride into power with high efficiency can be supplied.

It is a figure showing the composition of the engine system concerning this embodiment. It is a figure which shows the structure of the reactor which concerns on this embodiment. It is a figure which shows the structure of the air flow control apparatus (tumble valve) which concerns on this embodiment. It is a figure which shows the structure of the air flow control apparatus (swirl valve) which concerns on this embodiment. It is a figure which shows the relationship between the hydrogen concentration with respect to a combustion rate, and an air flow strength ratio. It is a figure which shows the relationship between an excess air ratio and a laminar-flow combustion speed. It is a figure which shows the relationship between the ratio of the liquid fuel in the fuel supplied to an engine, and a combustion speed. It is a figure explaining the estimation method of the hydrogen mixing ratio in the fuel supplied to the engine which concerns on this embodiment. It is a figure explaining the estimation method of the hydrogen mixing ratio in the fuel supplied to the engine which concerns on this embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 shows the configuration of the engine system in the present embodiment. As shown in FIG. 1, the engine system according to the present embodiment generates hydrogen rich gas from organic hydride using an engine 11 that is driven by burning a hydrogen rich gas and a hydrocarbon-based fuel, and heat of exhaust gas from the engine 11. A reactor 12, a hydrogen injector 16 that supplies the hydrogen-rich gas generated in the reactor 12 to the engine 11, a fuel injector 17 that supplies hydrocarbon fuel to the engine 11, and an intake pipe 29 of the engine 11 are provided. An air flow adjusting device 18 and a controller 19 (control means) for electronically controlling the system are provided.

Hereinafter, an embodiment using methylcyclohexane (hereinafter referred to as MCH) as an organic hydride will be described as an example. The reactor 12 is provided in the exhaust pipe 28 of the engine 11 in order to use the heat of the exhaust gas of the engine 11. MCH is a component that can easily add and release hydrogen by the catalytic reaction of the following formula (1).

The reaction for generating hydrogen from methylcyclohexane is an endothermic reaction with a reaction temperature of 250 to 350 ° C., and hydrogen can be easily generated by exhaust heat of the engine. MCH is stored in the organic hydride tank 13 and supplied from the organic hydride tank 13 to the reactor 12. Hydrogen produced in the reactor 12 and toluene as dehydrogenated fuel are sent to the separation device 14 through the pipe 24 and separated into hydrogen-rich gas and toluene. Toluene separated by the separation device 14 is stored in a dehydrogenation fuel tank through a pipe 25, and hydrogen-rich gas is supplied from the hydrogen injector 16 to the engine 11 through a pipe 26. The toluene in the dehydrogenated fuel tank 15 is supplied from the fuel injector 17 to the engine 11 through the pipe 27. A pipe 26 for supplying the hydrogen rich gas to the engine 11 is provided with a temperature detection device 21 and a pressure detection device 22 for detecting the temperature and pressure of the hydrogen rich gas. Further, a supply amount measuring device 23 for measuring the supply amount is provided in the pipe for supplying the organic hydride to the reactor 12. Further, a concentration detection device 20 for detecting the concentration of MCH in toluene separated by the separation device 14 is provided. The controller 19 receives the detection signals detected by these detection devices, the pulse widths from the hydrogen injector 16 and the fuel injector 17, and the pressure signal. The controller 19 calculates or estimates the hydrogen concentration in the fuel supplied to the engine 11 based on the input signal, and controls the opening degree of the air flow adjusting device 18 according to the hydrogen concentration. Thus, by controlling the opening degree of the air flow adjusting device 18 according to the hydrogen concentration, the combustion speed can be adjusted to a predetermined range, and the engine efficiency can be improved. Further, in the control of the combustion speed based on the excess air ratio, the exhaust gas temperature changes and affects the hydrogen generation in the reactor 12. However, in the control using the air flow control device 18 of the present embodiment, the exhaust gas temperature varies. Since the size can be reduced, the efficiency of the entire system can be improved.

In addition, although the form using the dehydrogenation fuel (toluene) was shown as a hydrocarbon fuel supplied to the engine 11 in FIG. 1, it is good also as a structure which supplies fuel other than a dehydrogenation fuel. Specifically, in addition to the configuration of FIG. 1, a tank for storing hydrocarbon fuel may be further provided, and the hydrocarbon fuel may be supplied from the pipe 27 to the engine 11 through the fuel injector 17.

In the present embodiment, a configuration using MCH (methylcyclohexane) is exemplified as the organic hydride, but, for example, cyclohexane, decalin, or the like can also be used. In addition to toluene, examples of dehydrogenated fuel produced by the dehydrogenation reaction include naphthalene and benzene.

As the hydrocarbon fuel to be supplied to the engine 11, in addition to the dehydrogenated fuel produced by the organic hydride dehydrogenation, fuels generally used in the engine such as light oil, gasoline and natural gas are used. be able to.

When dehydrogenated fuel is used as hydrocarbon fuel, there are the following advantages. Since the octane number of toluene (about 120) is higher than gasoline, which is a normal spark ignition fuel, knocking hardly occurs in the engine 11, and the engine 11 is operated at a high compression ratio to increase combustion efficiency. It is also possible. Specifically, in the case of a general spark ignition type engine 11, the compression ratio of about 13 is the maximum value, but by using toluene, the compression ratio can be increased to about 15. Further, in the case of the spark ignition type engine 11, the theoretical cycle is the Otto cycle, so that the thermal efficiency is improved when the compression ratio is increased.

The engine 11 is a four-stroke engine that repeats four cycles (intake, compression, combustion / expansion, and exhaust). The engine 11 includes a plurality of cylinders, a piston that reciprocates in the cylinder, a crankshaft connected to the piston via a connecting rod, an intake valve and an exhaust valve that are linked to the crankshaft, A spark plug to be controlled. The output of the engine 11 (rotation speed, torque, exhaust gas flow rate, etc.) is controlled by a controller 19 that controls the intake amount of fuel / air and ignition timing.

The hydrogen injector 16 is a device that injects hydrogen rich gas into the intake port and supplies it to the engine 11 in accordance with a command from the controller 19. Further, the position of the hydrogen injector 16 is not limited to this, and it may be configured to inject directly into a cylinder formed in the engine 11. The hydrogen-rich gas is separated by the separation device and then led to the hydrogen injector 16 through the pipe 26.

Since hydrogen having a high combustion speed is supplied to the engine 11 in this manner, lean and uniform combustion is possible in the engine 11, and pumping loss is reduced. Further, the specific heat ratio (constant volume specific heat (Cv) / constant pressure specific heat (Cp)) of the air-fuel mixture (a mixture of toluene, hydrogen and air) in the engine 11 is improved, and the thermal efficiency of the engine 11 can be increased.

The fuel injector 17 is a device that injects toluene into the intake port (port injection) in accordance with a command from the controller 19 and supplies it to the engine. Note that the position of the fuel injector 17 is not limited to this, and the fuel injector 17 may be directly injected into a cylinder formed in the engine 11. In addition, toluene is led from the dehydrogenation fuel tank 15 to the fuel injector 24 via the pipe 27.

Since the high-octane toluene is supplied to the engine 11 in this way, as described above, it is difficult for knocking to occur in the engine 11, and the engine 11 can be operated at a high compression ratio to increase combustion efficiency. It becomes possible.

The exhaust gas outlet of the engine 11 is connected to the exhaust gas inlet of the reactor 12 by an exhaust pipe 28. The exhaust gas from the engine 11 is led to the reactor 12 after operating (rotating) the supercharger.

As shown in FIG. 2A, the reactor 12 includes a plurality of reaction cells 31 whose outer shape is columnar, and a cylindrical first casing 32 that accommodates the plurality of reaction cells 31. . MCH (hydrogen-containing fuel) flows in each reaction cell 31, and high-temperature exhaust gas flows outside the reaction cell 31 and in the first casing 32.

The first casing 32 and the second casing 34 which will be described later are made of metal (for example, SUS) so as to have high thermal conductivity. In addition, the shape of the 1st casing 32 and the 2nd casing 34 is not limited to cylindrical shape, For example, a square cylinder shape and a polygonal cylinder shape may be sufficient.

As shown in FIG. 2B, the reaction cell 31 includes a plurality of stacked reaction sheets 33 and a second casing 34 in which the plurality of reaction sheets 33 are accommodated.

As shown in FIG. 2 (c), each reaction sheet 33 includes a base metal foil 35, a porous layer 36 formed on each surface of the metal foil 35, and a catalyst 37 supported on the porous layer 36. And. That is, each reaction sheet 33 has a three-layer structure in which the porous layer 36 supported by the catalyst 37, the metal foil 35, and the porous layer 36 supported by the catalyst 37 are stacked in this order.

Note that a gap through which MCH, generated hydrogen and toluene can flow is formed between the reaction sheets 33 adjacent to each other in the thickness direction.

Also, since the reaction sheet 33 is in the form of a sheet, its heat capacity is small, heat is quickly conducted through the reaction sheet 33, and the temperature of the catalyst 37 is quickly raised to a temperature at which the catalyst functions well. Thereby, the efficiency of the decomposition reaction which decomposes | disassembles MCH into hydrogen and toluene is high.

Furthermore, each reaction sheet 33 is formed with a plurality of through holes 33a. As a result, the heat of the exhaust gas is favorably conducted in the thickness direction, and MCH, generated hydrogen and toluene are also favorably passed in the thickness direction.

The metal foil 35 is made of, for example, an aluminum foil and has a thickness of about 50 to 200 μm.

However, the metal foil 35 may not be provided, or instead of the metal foil 35, a porous layer serving as a base may be provided, and the entire reaction sheet 33 may have a porous structure.

The porous layer 36 is a layer for supporting the catalyst 37 and has a plurality of pores through which MCH, generated hydrogen and toluene can flow. Such a porous layer 36 is made of an oxide mainly composed of alumina, for example.

Catalyst 37 is a catalyst for decomposing MCH to generate hydrogen and toluene (see formula (1)). Such a catalyst 37 is composed of at least one selected from, for example, platinum, nickel, palladium, rhodium, iridium, ruthenium, molybdenum, rhenium, tungsten, vanadium, osmium, chromium, cobalt, iron and the like.

The separation device 14 is a device that separates hydrogen and toluene. The separation device 14 according to the present embodiment cools a mixture of hydrogen and toluene by air cooling, thereby liquefying only toluene (boiling point: 110 ° C.) and separating it into a hydrogen-rich gas and toluene. . Therefore, for example, on the outer peripheral surface of the separation device 14, heat radiating fins (not shown) for promoting air-cooling are provided.

The separation method is not limited to this, and other methods such as a pressure swing adsorption device or a hydrogen permeable membrane (Pd membrane or the like) that selectively permeates hydrogen may be used.

The hydrogen rich gas separated by the separation device 14 is supplied to the hydrogen injector 16 through the pipe 26. In addition, the structure provided with the pump which pumps hydrogen into the piping 26 may be sufficient.

On the other hand, the toluene separated by being liquefied by the separator 14 flows through the piping 25 extending from the bottom of the separator 52 by its own weight, and is stored in the dehydrogenation fuel tank 15. The pipe 27 may be provided with a pump that pumps the toluene in the tank 54 to the fuel injector 17.

Note that a small amount of dehydrogenated fuel such as toluene is mixed in the hydrogen gas separated by the separator 14. The hydrogen rich gas means a hydrogen gas containing such a dehydrogenated fuel.

The controller 19 is a control device that electronically controls the engine system, and includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, and exhibits various functions according to programs stored therein. It is designed to control various devices.

An air flow adjusting device 18 that adjusts the flow is mounted in the middle of the intake pipe of the engine. The air flow adjusting device 18 only needs to form a swirl flow or a tumble flow in the cylinder, and can be realized by a valve means such as a swirl control valve or a tumble control valve disposed at a part of the intake port. 3 and 4 show examples of tumble valves and swirl valves. FIG. 3 shows a tumble valve, which shows a cross-sectional shape in the longitudinal direction of the engine. The tumble valve 18a is located in the intake pipe 29 of the engine, and a vertical vortex is generated in the engine cylinder by changing the flow path position of the air flowing through the intake pipe 29 by the tumble valve 18a. On the other hand, FIG. 4 shows the swirl valve 18b and shows the cross-sectional shape of the engine. As shown in the drawing, the intake pipe has a shape for generating a lateral vortex (swirl), and an air flow valve is installed on one of the intake pipes, and the swirl strength is adjusted by the opening degree. The air flow in the engine can be changed by changing the flow path cross-sectional position of the air supply pipe supplied to the engine. Further, the air flow can be enhanced by stopping the opening of the intake valve of the engine or one of the plurality of intake valves. The smaller the opening of the tumble valve 18a and the swirl valve 18b, the smaller the flow passage cross-sectional area of the intake pipe 29 and the stronger the air flow strength (tumble strength, swirl strength). The stronger the air flow, the better the combustion rate. Therefore, the combustion speed can be controlled by adjusting the opening degree of the tumble valve 18a or the swirl valve 18b. 1, 3, and 4 show the configuration in which the air flow valve is provided in the intake pipe, the air flow adjusting device 18 may be any device that forms a swirl flow or a tumble flow. May be provided in the combustion chamber of the engine 11.

Generally, hydrogen has a significantly higher combustion speed than hydrocarbon-based fuels. Therefore, under the same combustion conditions as hydrocarbon-based hydrogen, there is a problem that engine cooling loss increases and thermal efficiency decreases.

The laminar combustion rate formula of gasoline is shown in the following formula (2).

The hydrogen laminar burning velocity equation is shown in the following equation (3).

S _L is a laminar burning velocity, and P and T are pressure and temperature, respectively. The subscripts u and 0 are the engine internal state and the standard state. Φ is the equivalent ratio, and x _egr is the EGR rate.

When comparing the laminar burning rates of hydrogen and gasoline, the laminar burning rate of hydrogen is about 10 times that of gasoline. In addition, the higher the pressure, the lower the laminar combustion rate, while the higher the pressure, the higher the laminar combustion rate of hydrogen. Therefore, in the case of an engine with a high load condition and a high compression ratio, there is a feature that the amount of change in the combustion speed due to the change in the hydrogen mixing ratio becomes larger.

Therefore, it is necessary to optimally adjust the combustion rate according to the hydrogen mixing ratio. From equations (2) and (3), the laminar combustion speed also changes with respect to the excess air ratio as shown below. However, the concentration of the inert gas supplied into the combustion chamber changes, so that it is supplied to the hydrogen generator. As a result, the exhaust gas temperature is likely to change, and the amount of hydrogen produced from the hydrogen generator is easily affected. Therefore, it is important to incorporate into the system a technique for adjusting the combustion rate due to changes in air flow. FIG. 5 shows the relationship between the in-cylinder flow strength for making the combustion speed constant with respect to the hydrogen concentration in the fuel under the conditions of constant torque and rotational speed. When the excess air ratio is constant, the combustion speed increases as the hydrogen mixing ratio in the fuel supplied to the engine increases. Therefore, in order to make the combustion speed constant, control is performed to reduce the air flow so that the increase in the combustion speed is suppressed as the hydrogen mixing ratio in the fuel increases. The air flow is controlled by controlling the opening degree of the tumble valve 17a or the swirl valve 17b of the air flow adjusting device.

Also, the combustion speed changes due to the change in excess air ratio. This is because, as shown in FIG. 6, the dependence of the laminar combustion rate of hydrogen on the excess air ratio is smaller than that of hydrocarbon fuel, so the laminar combustion rate at a high excess air rate is greatly influenced by the hydrogen mixing ratio. Is the factor. Therefore, the amount of change in the combustion rate due to the change in the hydrogen mixing ratio is greater when the excess air ratio is larger than when the excess air ratio is small. That is, the dependence of the combustion rate on the hydrogen mixing ratio increases as the air excess ratio increases. Therefore, as shown in FIG. 5, the amount of change in the in-cylinder flow strength increases when the excess air ratio is high. When operating with the excess air ratio changed, control is performed to correct the valve opening so that the higher the excess air ratio, the greater the amount of decrease in air flow as the hydrogen mixing ratio increases.

Further, as shown in FIG. 7, the air flow is also adjusted by the ratio of the liquid fuel in the hydrocarbon fuel supplied to the engine. In the case of liquid fuel, it passes through the process of evaporation, mixing with air, and ignition in the engine. Therefore, the amount of evaporation is increased compared to gas fuel, and the mixture tends to become non-uniform. Accordingly, the combustion speed is optimized by increasing the air flow.

As described above, by controlling the strength of the air flow according to the hydrogen mixing ratio so that the combustion speed is in a predetermined range, it is possible to reduce the increase in cooling loss due to the increase in the combustion speed. Next, a method for estimating the hydrogen mixing ratio supplied to the engine will be described. FIG. 8 shows an estimation method 1 of the hydrogen mixing ratio supplied to the engine. The flow rate of the hydrogen rich gas estimates the flow rate of the hydrogen rich gas supplied to the engine 11 from the pressure and pulse width of the hydrogen injector 16. Further, a small amount of toluene corresponding to the vapor pressure is mixed in the hydrogen rich after the toluene and hydrogen produced in the reactor 12 are separated by the separation device 14. The toluene concentration is calculated by assuming a saturated vapor pressure based on the temperature and pressure values of the hydrogen rich gas detected by the temperature detector 21 and the pressure detector 22. Further, the flow rate of the hydrocarbon-based fuel supplied to the engine 11 is estimated from the pressure of the fuel injector 17 and the pulse width. The hydrogen concentration in the fuel supplied to the engine is estimated from the flow rates of the hydrogen-rich gas and hydrocarbon fuel supplied to the engine 11 and the toluene concentration contained in the hydrogen-rich gas. By this method, when the hydrocarbon fuel is a liquid fuel such as light oil, the ratio of the liquid fuel can also be grasped.

Fig. 9 shows the estimation method 2 of the hydrogen mixing ratio in the fuel supplied to the engine. In the reaction of the reaction formula (1), almost no by-products are generated, and therefore the production efficiency of producing hydrogen from MCH can be grasped by measuring the concentration of MCH in toluene after production by the concentration detector 20. As a sensor for detecting the MCH concentration in toluene, a sensor using the difference in density and dielectric constant between toluene and MCH can be used.

The supply amount of MCH supplied to the reactor 12 is measured by the supply amount measuring device 23. By grasping the amount of MCH supplied to the reactor 12 and the hydrogen generation efficiency, the amount of hydrogen generation can be calculated by the following equation (4).

Next, the toluene concentration in the hydrogen gas and the hydrocarbon-based supply amount to the engine 11 are estimated by the same method as the estimation method 1. Then, the hydrogen concentration in the fuel supplied to the engine is estimated from the hydrogen gas generation amount, the supply amount of the hydrocarbon-based fuel, and the toluene concentration contained in the hydrogen gas. By this method, when the hydrocarbon fuel is a liquid fuel such as light oil, the ratio of the liquid fuel can also be grasped.

The controller 19 uses the estimation method 1 or the estimation method 2 to estimate the hydrogen concentration in the fuel supplied to the engine based on the signals input from the respective detection devices and injectors, and based on the result, the air A valve opening control command signal is output to the flow control device 18. The air flow adjusting device 18 controls the valve opening degree according to a control command signal from the controller 19 to control the strength of the air flow. By controlling the strength of the air flow according to the hydrogen concentration, it is possible to keep the combustion speed within a predetermined range even if the hydrogen concentration changes. Thereby, while suppressing the thermal efficiency fall of an engine, since the influence on the dehydrogenation reaction of a reactor can be made small, the efficiency of the whole system can be kept stable.

In the engine system, the hydrogen concentration in the fuel supplied to the engine and the excess air ratio are determined so as to increase the efficiency with respect to the engine operating range (torque, rotation speed). On the other hand, in the engine system that supplies the hydrogen-rich gas generated in the reactor to the engine, the hydrogen-rich gas contains dehydrogenated fuel and its concentration varies as described above. Therefore, when the hydrogen concentration in the fuel is adjusted only by the supply amounts of the hydrogen injector and the fuel injector, the hydrogen concentration in the fuel varies. On the other hand, it is preferable to correct the supply amounts from the hydrogen injector and the fuel injector using the estimation result of the hydrogen concentration in the hydrogen rich gas supplied to the engine described in the estimation methods 1 and 2. Thereby, the hydrogen concentration in the hydrogen-rich gas is taken into consideration, so that the hydrogen concentration in the fuel supplied to the engine can be accurately controlled. The controller 19 controls the supply amounts from the hydrogen injector and the fuel injector.

Typical effects of the engine system of the present embodiment described above are as follows.

When the combustion rate is controlled by the excess air ratio, there are the following restrictions. That is, misfire occurs when the excess air ratio exceeds a predetermined value, and therefore the maximum excess air ratio that can be combusted is determined according to the hydrogen mixing ratio. Also, from the viewpoint of exhaust purification of NO _x , unburned hydrocarbons, CO, etc., when using a three-way catalyst, the excess air ratio is around 1, and to eliminate the need for NO _x purification, the excess air ratio is 1.8. It is desirable to set it above. For this reason, there is a limit to the adjustment of the excess air ratio, and it becomes difficult to control the combustion rate only with the excess air ratio. Moreover, since the exhaust gas temperature changes with the change in the excess air ratio, the amount of hydrogen produced in the reactor changes. Therefore, controlling the combustion rate with the excess air ratio affects the hydrogen generation, and as a result, the efficiency of the entire system may be reduced. On the other hand, in the engine system of the present embodiment, by controlling the strength of the air flow according to the hydrogen concentration, the thermal efficiency of the engine is suppressed and the influence on the dehydrogenation reaction of the reactor is small. The overall efficiency can be kept stable. In addition to the control by the air flow of this embodiment, the control by the air excess rate can be used together for the control of the combustion speed.

DESCRIPTION OF SYMBOLS 11 Engine 12 Reactor 13 Organic hydride tank 14 Separation device 15 Dehydrogenation fuel tank 16 Hydrogen injector 17 Fuel injector 18 Air flow control device

18a Tumble valve

18b Swirl valve 19 Controller 20 Concentration detection device 21 Temperature detection device 22 Pressure detection device 23 Supply Quantity measuring device 28 Exhaust pipe 29 Intake pipe 31 Reaction cell 32 First casing 33 Reaction sheet 34 Second casing 35 Metal foil 36 Porous layer 37 Catalyst

Claims

An engine system using hydrogen as a part of fuel,
An engine that generates power by burning hydrogen and hydrocarbon fuel;
A reactor having a catalyst for generating hydrogen and dehydrogenated fuel from a hydrogen-containing fuel by a dehydrogenation reaction using heat of exhaust gas of the engine;
Hydrogen supply means for supplying the hydrogen-rich gas generated in the reactor to the engine;
An air flow adjusting device for adjusting the flow of air supplied to the engine;
Control means for controlling the operation of the air flow control device,
The engine system according to claim 1, wherein the control means controls the air flow control device in accordance with a ratio of hydrogen in the fuel supplied to the engine.
In claim 1,
The air flow adjusting device comprises means for forming a swirl flow or a tumble flow,
The engine system, wherein the control means performs control to reduce the strength of the tumble flow or swirl flow as the proportion of hydrogen in the fuel supplied to the engine increases.
In claim 1,
The air flow control device is a tumble valve or a swirl valve;
The engine system according to claim 1, wherein the control means performs control to reduce the opening degree of the tumble valve or swirl valve as the proportion of hydrogen in the fuel supplied to the engine increases.
4. The engine system according to claim 3, wherein the control means controls the air flow adjusting device in accordance with a ratio of hydrogen in the fuel supplied to the engine and an excess air ratio.
In claim 1,
A separation device for separating hydrogen produced in the reactor and dehydrogenated fuel;
An engine system, wherein the hydrogen rich gas separated by the separation device is supplied to the engine by the hydrogen supply means.
In claim 5,
An engine system using the dehydrogenated fuel as the hydrocarbon-based fuel supplied to the engine.
In claim 3,
First flow rate estimating means for estimating a flow rate of the hydrogen-rich gas supplied to the engine;
Second flow rate estimating means for estimating a flow rate of the hydrocarbon fuel supplied to the engine;
A concentration estimation means for estimating the concentration of dehydrogenated fuel contained in the hydrogen rich gas supplied to the engine,
The control means estimates the proportion of hydrogen in the fuel supplied to the engine based on the information estimated by the first flow rate estimating means, the second flow rate estimating means, and the concentration estimating means, An engine system that controls the air flow control device based on an estimation result.
In claim 7,
A hydrogen supply pipe for supplying a hydrogen-rich gas to the hydrogen supply means;
The concentration estimation means includes a temperature detection device and a pressure detection device provided in the hydrogen supply pipe, and is included in the hydrogen rich gas from the temperature and pressure of the hydrogen rich gas detected by the temperature detection device and the pressure detection device. An engine system for estimating a concentration of the dehydrogenated fuel.
In claim 7,
The first flow rate estimation means is configured to calculate the hydrogen-rich gas from the amount of hydrogen-containing fuel supplied to the reactor and the concentration of unreacted hydrogen-containing fuel contained in the dehydrogenated fuel separated by the separator. Engine system characterized by estimating the flow rate of the engine.
In claim 7,
An engine system, wherein the concentration of hydrogen supplied to the engine is corrected based on the concentration of dehydrogenated fuel in the hydrogen-rich gas estimated by the concentration estimating means.