JP2021055660A - Fuel reforming engine - Google Patents

Abstract

To provide a fuel reforming engine capable of increasing an equivalence ratio of premixed gas sucked into a fuel reforming cylinder with a small amount of fuel supply.SOLUTION: A fuel reforming engine 1 comprises: a fuel reforming cylinder 2 which reforms supplied fuel; and an output cylinder 3 which obtains engine output through combustion of reformed fuel produced in the fuel reforming cylinder 2 and supplied thereto. An intake passage 79 of the fuel reforming cylinder 2 is connected only to an exhaust passage 61 of the output cylinder 3.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a fuel reforming engine having a fuel reforming cylinder.

As shown in Patent Document 1, a fuel reforming engine including a fuel reforming cylinder and an output cylinder is known. This type of fuel reforming engine reforms fuel in a fuel reforming cylinder. The engine output is obtained by burning the reformed fuel (hereinafter referred to as reformed fuel) in the output cylinder.

Specifically, fuel such as gasoline, kerosene, light oil, or heavy oil is supplied to the fuel reforming cylinder, and the air-fuel mixture having a high equivalent ratio is adiabatically compressed in the fuel reforming cylinder. As a result, the fuel is reformed in a high temperature and high pressure environment, and a reformed fuel (high octane fuel) having high antiknock properties such as hydrogen, carbon monoxide, and methane is produced. The engine output is obtained by supplying this reformed fuel together with air to the output cylinder and burning the lean mixture (uniform lean combustion) in the output cylinder.

According to this type of fuel reforming engine, uniform lean burn is performed in the output cylinder, so that it is possible to reduce NOx emissions and soot emissions. In addition, since fuel with high antiknock property is burned, knocking is suppressed and diesel micropilot ignition (ignition of reformed fuel by supplying a small amount of fuel into the output cylinder) at the optimum time. Since combustion can be realized, thermal efficiency can be improved.

JP-A-2018-9529

When reforming fuel in a fuel reforming cylinder, the reforming efficiency can be increased by increasing the equivalent ratio of the premixture sucked into the fuel reforming cylinder, but in order to increase the equivalent ratio, a large amount of fuel is used. It is necessary to supply the fuel, and the gas temperature at the compression top dead center of the fuel reforming cylinder may decrease due to a decrease in the specific heat ratio of the air-fuel mixture or the latent heat of vaporization due to the supplied fuel, and the reforming reaction may not proceed sufficiently.

An object of the present disclosure is to provide a fuel reforming engine capable of increasing the equivalent ratio of the premixture sucked into the fuel reforming cylinder with a small fuel supply amount.

The fuel reforming engine of the present disclosure includes a fuel reforming cylinder that reforms the supplied fuel and a fuel reforming cylinder.
An output cylinder to which the reformed fuel produced by the reformed fuel is supplied and the engine output is obtained by combustion of the reformed fuel is provided.
The intake passage of the fuel reforming cylinder is connected only to the exhaust passage of the output cylinder.

According to such a configuration, the equivalent ratio of the premixture sucked into the fuel reforming cylinder can be increased with a small fuel supply amount.

The figure which shows the system configuration of the fuel reforming engine of this embodiment The figure which shows the relationship between the equivalent ratio of the air-fuel mixture in the fuel reforming chamber, the initial temperature before compression of the air-fuel mixture introduced into the fuel reforming chamber, the reforming reaction impossible region, and the distribution of reforming efficiency. The equivalent ratio of the air-fuel mixture in the fuel reforming chamber, the initial temperature of the air-fuel mixture introduced into the fuel reforming chamber before compression, the reforming reaction impossible region, and the distribution of the compressed end gas temperature of the fuel reforming cylinder. Diagram showing the relationship Diagram showing the system configuration around the output cylinder

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

<System configuration of fuel reforming engine 1>
FIG. 1 is a diagram showing a system configuration of the fuel reforming engine 1 of the present embodiment. As shown in FIG. 1, the fuel reforming engine 1 has a fuel reforming cylinder 2 and an output cylinder 3. The fuel reforming engine 1 has an intake system 4 and a reformed fuel supply system 5 as a piping system for supplying (introducing) gas or discharging (exhausting) gas to the fuel reforming cylinder 2 and the output cylinder 3. , Exhaust system 6, and EGR system 7.

[Fuel reforming cylinder and output cylinder]
The fuel reforming cylinder 2 and the output cylinder 3 are reciprocating type. Specifically, each of the cylinders 2 and 3 is configured such that the pistons 22 and 32 are reciprocally housed in the cylinder bores 21 and 31 formed in the cylinder block (not shown). In the fuel reforming cylinder 2, the fuel reforming chamber 23 is formed by the cylinder bore 21, the piston 22, and the cylinder head (not shown). In the output cylinder 3, the combustion chamber 33 is formed by the cylinder bore 31, the piston 32, and the cylinder head (not shown).

In the fuel reforming engine 1 according to the present embodiment, the cylinder block is provided with four cylinders, one of which is configured as the fuel reforming cylinder 2 and the other three cylinders are configured as the output cylinder 3. Has been done. Then, the reformed fuel produced by the fuel reforming cylinder 2 is supplied to each output cylinder 3. The number of each cylinder 2, 3 is not limited to this. For example, the cylinder block may be provided with six cylinders, two of which may be configured as the fuel reforming cylinder 2 and the other four cylinders may be configured as the output cylinder 3.

The pistons 22 and 32 of the cylinders 2 and 3 are connected to the crankshaft 11 via connecting rods 24 and 34, respectively. As a result, the motion is converted between the reciprocating motion of the pistons 22 and 32 and the rotational motion of the crankshaft 11. The crankshaft 11 can be connected to the output shaft via a clutch mechanism (not shown). The piston 22 of the fuel reforming cylinder 2 and the piston 32 of the output cylinder 3 are connected to each other via connecting rods 24 and 34 and a crankshaft 11. Therefore, it is possible to transmit the power between the cylinders 2 and 3 and to transmit the power output from the cylinders 2 and 3 to the output shaft.

The fuel reforming cylinder 2 is provided with an injector 25 that supplies fuel such as gasoline, kerosene, light oil, or heavy oil as fuel before reforming to the fuel reforming chamber 23. In the fuel reforming chamber 23, the fuel is supplied from the injector 25, so that the air-fuel mixture having a high equivalent ratio is adiabatically compressed. As a result, the fuel is reformed in a high temperature and high pressure environment, and a reformed fuel having high antiknock properties such as hydrogen, carbon monoxide, and methane is produced.

The output cylinder 3 is provided with an injector 35 that supplies fuel such as light oil to the combustion chamber 33. In the combustion chamber 33, the reformed fuel produced by the fuel reforming cylinder 2 is supplied together with air, and the lean premixed combustion of the lean mixture is performed in the combustion chamber 33. As a result, the crankshaft 11 rotates with the reciprocating movement of the piston 32, and an engine output is obtained.

(Intake system)
The intake system 4 introduces air (fresh air) into the combustion chamber 33 of the output cylinder 3.

The intake system 4 includes an intake passage 41. The intake passage 41 is provided with a compressor wheel 12a of the turbocharger 12. Further, the intake passage 41 is provided with an intake cooler 44 (intercooler). The intake passage 41 communicates with the intake port of the output cylinder 3. An intake valve 36 is arranged so as to be openable and closable between the intake port and the combustion chamber 33 of the output cylinder 3.

(Reformed fuel supply system)
The reformed fuel supply system 5 supplies the reformed fuel (hereinafter, also referred to as reformed gas) generated by the reformed fuel cylinder 2 toward the combustion chamber 33 of the output cylinder 3.

The reformed fuel supply system 5 includes a reformed fuel supply passage 51. The reformed fuel supply passage 51 is provided with a reformed fuel cooler 52. The upstream end of the reformed fuel supply passage 51 communicates with the exhaust port of the reformed fuel cylinder 2. An exhaust valve 27 is arranged so as to be openable and closable between the exhaust port and the fuel reforming chamber 23 of the fuel reforming cylinder 2. Further, the downstream end of the reformed fuel supply passage 51 communicates with the intake passage 41. Therefore, the reformed fuel generated in the fuel reforming cylinder 2 is mixed with the air flowing through the intake passage 41 and supplied to the combustion chamber 33 of the output cylinder 3.

(Exhaust system)
The exhaust system 6 discharges the exhaust gas generated in the output cylinder 3. The exhaust system 6 includes an exhaust passage 61. The exhaust passage 61 is provided with a turbine wheel 12b (corresponding to an exhaust turbine) of the turbocharger 12. The exhaust passage 61 communicates with the exhaust port of the output cylinder 3. An exhaust valve 37 is arranged so as to be openable and closable between the exhaust port and the combustion chamber 33 of the output cylinder 3.

(EGR system)
The EGR system 7 supplies a part of the exhaust gas flowing through the exhaust passage 61 toward the fuel reforming chamber 23 of the fuel reforming cylinder 2.

The EGR system 7 includes an EGR passage 71. The upstream end of the EGR passage 71 is connected to the exhaust passage 61 on the upstream side of the turbine wheel 12b of the exhaust passage 61. Since high-temperature exhaust gas flows through the EGR passage 71, it is preferable to insert the flexible pipe 71a into the pipe in consideration of deformation of the pipe.

The downstream end of the EGR passage 71 communicates with the intake passage 79 of the fuel reforming cylinder 2. The intake passage 79 is communicated with the intake port of the fuel reforming cylinder 2, and an intake valve 26 is arranged so as to be openable and closable between the intake port and the fuel reforming chamber 23 of the fuel reforming cylinder 2.

The EGR passage 71 is provided with an EGR gas cooler 72. Further, an EGR gas amount adjusting valve 73 (corresponding to the first flow rate control valve) is provided on the downstream side of the EGR gas cooler 72 in the EGR passage 71. Further, the EGR system 7 is provided with a cooler bypass passage 74 for allowing the EGR gas to flow by bypassing the EGR gas cooler 72. Further, a bypass amount adjusting valve 75 is provided on the upstream side of the EGR gas cooler 72 in the EGR passage 71.

The coolers 44, 52, and 72 provided in each of the above-mentioned systems use engine cooling water, seawater, or the like as a cooling heat source for cooling the gas. Further, these coolers 44, 52, 72 may be air-cooled.

<Operation of fuel reforming engine 1>
Next, the operation of the fuel reforming engine 1 will be described.

The air introduced into the intake passage 41 is pressurized by the compressor wheel 12a of the turbocharger 12. The air introduced into the intake passage 41 is supplied to the combustion chamber 33 of the output cylinder 3.

The EGR gas flowing through the EGR passage 71 is introduced into the fuel reforming chamber 23 of the fuel reforming cylinder 2. At this time, the amount of EGR gas introduced into the fuel reforming chamber 23 is adjusted by the EGR gas amount adjusting valve 73. Further, the temperature of the EGR gas introduced into the fuel reforming chamber 23 is adjusted by the amount of EGR gas bypassing the EGR gas cooler 72 according to the opening degree of the bypass amount adjusting valve 75. At this time, the flow rate and temperature of the EGR gas have a high equivalent ratio in the fuel reforming chamber 23, and the gas temperature in the fuel reforming chamber 23 can secure a temperature at which the fuel can be reformed satisfactorily. It will be adjusted. Specifically, the opening degree of the EGR gas amount adjusting valve 73 and the bypass amount adjusting valve 75 is, for example, the equivalent ratio in the fuel reforming chamber 23 when fuel is supplied from the injector 25 to the fuel reforming chamber 23. Created in advance based on experiments and simulations so that the gas temperature in the fuel reforming chamber 23 is set to 5.5 or higher (preferably 4.0 or higher) and is equal to or higher than the lower limit of the reformable reactionable temperature. It is set according to the opening setting map.

In this way, with the EGR gas introduced into the fuel reforming chamber 23 of the fuel reforming cylinder 2, fuel is supplied from the injector 25 to the fuel reforming chamber 23. The fuel supply amount from the injector 25 is basically set according to the engine required output. Specifically, the valve opening period of the injector 25 is set so that a target fuel supply amount can be obtained according to the fuel pressure supplied to the injector 25. Further, it is desirable that the valve opening timing of the injector 25 is set so that the injection of the target fuel supply amount is completed by the time the intake stroke of the fuel reforming cylinder 2 is completed, but the piston 22 is compressed. If the air-fuel mixture can be mixed uniformly before reaching near top dead center, the fuel injection period may be continued until the middle of the compression stroke. As a result, a homogeneous air-fuel mixture (air-fuel mixture having a high equivalent ratio) is generated in the fuel reforming chamber 23 by the time the piston 22 reaches the compression top dead center.

While the piston 22 moves toward the compression top dead center, the pressure and temperature of the fuel reforming chamber 23 rise, and in the fuel reforming chamber 23, an air-fuel mixture having a high equivalent ratio (for example, an equivalent ratio of 4.0 or more) Air-fuel mixture) is adiabatically compressed. As a result, the fuel is reformed by dehydrogenation reaction, partial oxidation reaction, steam reforming reaction, and thermal dissociation reaction in a high temperature and high pressure environment, and anti-knocking of hydrogen, carbon monoxide, methane, etc. Highly reformed fuel is produced.

The reformed fuel discharged from the fuel reforming chamber 23 is cooled in the reformed fuel cooler 52 as it flows through the reformed fuel supply passage 51. Cooling suppresses premature ignition of the reformed fuel in the intake passage 41 and the combustion chamber 33. The cooled reformed fuel is mixed with the air flowing through the intake passage 41 and supplied to the combustion chamber 33 of the output cylinder 3.

In this way, air and reformed fuel are introduced into the combustion chamber 33 of the output cylinder 3, and the equivalent ratio in the combustion chamber 33 is adjusted to about 0.1 to 0.8.

In the output cylinder 3, the dilute mixed gas is adiabatically compressed in the compression stroke, and when the piston 32 reaches the compression top dead center, a small amount of fuel is injected from the injector 35. As a result, the air-fuel mixture in the combustion chamber 33 is ignited, and lean premixed combustion is performed. If the air-fuel mixture in the combustion chamber 33 self-ignites (premixed compression self-ignition) without fuel injection from the injector 35, fuel injection from the injector 35 is not always necessary.

Due to combustion, the piston 32 reciprocates and the crankshaft 11 rotates to obtain an engine output. The engine output is transmitted to the output shaft. Further, a part of the engine output is used as a drive source for the reciprocating movement of the piston 22 in the fuel reforming cylinder 2.

According to the fuel reforming engine 1, since the lean mixture is burned (uniform lean burn) in the output cylinder 3, it is possible to reduce the NOx emission amount and the soot emission amount. As a result, it is possible to eliminate the need for an aftertreatment device for purifying the exhaust gas or to significantly reduce its capacity. In addition, since fuel with high antiknock property is burned, knocking is suppressed and combustion can be realized at an optimum time by diesel micropilot ignition, so that thermal efficiency can be improved.

<About the reforming reaction in the fuel reforming cylinder>
Only the exhaust gas (EGR gas) from the output cylinder 3 is introduced into the fuel reforming chamber 23 of the fuel reforming cylinder 2 according to the present embodiment. On the other hand, conventionally, the exhaust gas from the output cylinder 3 and air (fresh air) are mixed and introduced into the fuel reforming cylinder 2.

FIG. 2 shows the equivalent ratio of the air-fuel mixture in the fuel reforming chamber 23 (horizontal axis), the initial temperature of the air-fuel mixture introduced into the fuel reforming chamber 23 before compression (vertical axis), and the reforming reaction impossible region. , It is a figure which shows the relationship with the distribution of reforming efficiency. As shown in FIG. 2, the rate at which the fuel supplied to the fuel reforming cylinder 2 is converted into the energy of the reforming gas (reforming efficiency) can be increased as the equivalent ratio is higher. However, under the condition that the equivalent ratio is high, if the initial temperature corresponding to the intake air temperature is low, the gas temperature in the fuel reforming chamber 23 at the time when the piston 22 reaches the compression top dead center in the fuel reforming cylinder 2 (hereinafter, , The temperature of the compressed end gas) drops, so there is a problem that the reforming reaction does not occur.

FIG. 3 shows the equality ratio of the air-fuel mixture in the fuel reforming chamber 23 (horizontal axis), the initial temperature of the air-fuel mixture introduced into the fuel reforming chamber 23 before compression (vertical axis), and the reforming reaction impossible region. It is a figure which shows the relationship with the distribution of the gas temperature (compression end gas temperature) in a fuel reforming chamber 23 at the time when a piston 22 reaches a compression top dead center in a fuel reforming cylinder 2. As shown in FIG. 3, the reforming reaction occurs when the compressed end gas temperature is equal to or higher than a certain value. Therefore, under the condition that the equivalent ratio is high, it is necessary to supply the gas having a temperature as high as possible to the fuel reforming cylinder 2.

According to the fuel reforming engine 1 of the present embodiment, the high-temperature exhaust gas from the output cylinder 3 can be introduced into the fuel reforming cylinder 2 as it is, so that the compressed end gas temperature can be surely raised.

Further, since the output cylinder 3 is operated under the condition of an excess air ratio of about 1.5 to 2.5, a few percent of oxygen remains in the exhaust gas. Therefore, by directly introducing this exhaust gas into the fuel reforming cylinder 2, a high equivalent ratio can be realized with a small amount of fuel supply, and the air-fuel mixture in the fuel reforming cylinder 2 by injecting a large amount of fuel can be realized. It is possible to prevent the compression end gas temperature from decreasing due to the decrease in the specific heat ratio and the latent heat of vaporization, and to efficiently raise the compression end gas temperature.

As described above, the fuel reforming engine 1 of the present embodiment includes the fuel reforming cylinder 2 that reforms the supplied fuel and the fuel reforming cylinder 2.
An output cylinder 3 to which the reformed fuel generated by the fuel reforming cylinder 2 is supplied and the engine output is obtained by combustion of the reformed fuel is provided.
The intake passage 79 of the fuel reforming cylinder 2 is connected only to the exhaust passage 61 of the output cylinder 3.

According to this configuration, the equivalent ratio of the premixture sucked into the fuel reforming cylinder 2 can be increased with a small fuel supply amount.

Further, in the fuel reforming engine 1 of the present embodiment, the intake passage 79 of the fuel reforming cylinder 2 is connected to the exhaust passage 61 on the upstream side of the turbine wheel 12b provided in the exhaust passage 61 of the output cylinder 3. It is preferable to have.

This is because the pressure and temperature of the gas discharged from the turbine wheel 12b are lowered, and the amount of oxygen and the temperature required for reforming cannot be maintained. By introducing the exhaust gas on the upstream side of the turbine wheel 12b, the volumetric efficiency of the fuel reforming cylinder 2 can be increased, and the required amount of reforming gas can be supplied even under the condition that the output of the output cylinder 3 is high. Can be done.

Further, in the fuel reforming engine 1 of the present embodiment, a means for detecting or estimating the oxygen concentration in the exhaust gas of the exhaust passage 61 of the output cylinder 3 is provided.
Based on the detected or estimated oxygen concentration in the exhaust gas, the fuel supply amount to the fuel reforming cylinder 2 is adjusted so that the equivalent ratio in the fuel reforming cylinder 2 becomes a value of 2.0 to 10.0. You may try to do it.

As a method of acquiring the oxygen concentration in the exhaust gas, a method _{of detecting with an O 2} sensor provided in the pipe or a method of calculating based on the operating conditions of the output cylinder 3 and the fuel reforming cylinder 2 may be used.

For the oxygen concentration in the exhaust gas, the reformed gas introduced into the output cylinder 3, the fuel supplied to the output cylinder 3, and the amount of air introduced into the output cylinder 3 are calculated respectively, and it is assumed that they are completely burned. It can be obtained by calculating the amount of each component after the combustion reaction. For example, in the configuration of FIG. 4, when the composition and flow rate of the reformed gas are known in advance, the fresh air amount and the EGR gas amount are obtained from the pressure and temperature of the intake and exhaust of the output cylinder 3 and the opening degree of the EGR valve 80. Can be calculated. The pressure and temperature of the intake and exhaust of the output cylinder 3 are detected by the pressure sensors 81 and 82 and the temperature sensors 83 and 84 provided in the intake and exhaust passages of the output cylinder 3.

Next, the fuel supply amount _mfuel can be obtained by the following equations (1) and (2).

Here, phi _rfm the target equivalent ratio of the fuel reforming cylinder 2, alpha _Fuel is stoichiometric hydrogen carbonate fuel _{C a H b O c, m} gas_in exhaust gas amount is sucked into the fuel reforming cylinder 2, MW _gas is the mole mass of the exhaust gas of the output cylinder 3, MW _fuel is the mole mass of the fuel, and φ _{O2_gas} is the mole fraction of O2 in the exhaust gas.

Further, the fuel reforming engine 1 of the present embodiment includes means for detecting the amount of exhaust gas introduced from the exhaust passage 61 of the output cylinder 3 to the intake passage 79 of the fuel reforming cylinder 2.
An EGR gas amount adjusting valve 73 for adjusting the exhaust gas amount is provided.
The EGR gas amount adjusting valve 73 may be controlled so that the equivalent ratio in the fuel reforming cylinder 2 becomes a value of 2.0 to 10.0 according to the operating conditions of the output cylinder 3.

The composition of the reformed gas can be controlled by the equivalent ratio in the fuel reforming cylinder 2 and the gas temperature. However, the amount of reformed gas needs to be adjusted so that the mass balance is established according to the output of the output cylinder 3.

For example, when the output of the output cylinder 3 is low, even if a large amount of reformed gas is generated, it cannot be consumed completely. Therefore, the amount of EGR gas introduced into the fuel reformed cylinder 2 by reducing the opening degree of the EGR gas amount adjusting valve 73 is reduced. By reducing the amount of fuel, the reforming reaction can occur at a high equivalent ratio even with a small amount of fuel supply. On the other hand, when the output of the output cylinder 3 is high, a large amount of reformed gas is generated by increasing the opening degree of the EGR gas amount adjusting valve 73 and increasing the amount of EGR gas introduced into the fuel reforming cylinder 2. Can be done.

Specifically, equation (3) to calculate a target exhaust gas amount _{m gas} under the conditions of the target equivalent ratio _phi rfm = 2.0 to 10.0 in, EGR gas amount adjustment based on the target exhaust gas amount _{m gas} The opening degree of the valve 73 is adjusted.

As a means for detecting the amount of exhaust gas, it may be detected by a Venturi type flow meter installed in the pipe, or it may be estimated based on the outlet gas pressure and temperature of the output cylinder 3.

Further, the fuel reforming engine 1 of the present embodiment includes an EGR gas cooler 72 provided between the exhaust passage 61 of the output cylinder 3 and the intake passage 79 of the fuel reforming cylinder 2.
A cooler bypass passage 74 that bypasses the EGR gas cooler 72,
A bypass amount adjusting valve 75 for adjusting the amount of EGR gas flowing into the EGR gas cooler 72 is provided.
The bypass amount adjusting valve 75 is controlled so that the gas temperature (compressed end gas temperature) in the fuel reforming cylinder 2 at the time when the piston 22 reaches the compression top dead center in the fuel reforming cylinder 2 becomes a predetermined value. You may try to do it.

The composition of the reformed gas strongly depends on the temperature of the compressed end gas. When the temperature of the compressed end gas is low, the thermal decomposition reaction becomes insufficient and higher hydrocarbons remain in the reformed gas. Further, when the compressed end gas temperature falls below a certain value, the reforming reaction does not occur, and the supplied fuel is discharged as it is.

On the other hand, if the temperature of the compressed end gas is too high, a large amount of soot is generated in the reformed gas, and the cylinder bore 21 becomes hot, so that there is a risk of reliability deterioration such as seizure of the piston 22 and cracking of the head. To increase.

Therefore, an EGR gas cooler 72 for adjusting the temperature of the exhaust gas is provided between the exhaust passage 61 of the output cylinder 3 and the intake passage 79 of the fuel reforming cylinder 2, and the EGR gas cooler is provided by the bypass amount adjusting valve 75. By controlling the amount of EGR gas flowing into 72, the inlet gas temperature of the fuel reforming cylinder 2 is controlled so that the compressed end gas temperature of the fuel reforming cylinder 2 becomes a predetermined value.

Specifically, under operating conditions where the output of the output cylinder 3 is low, it is desirable that the temperature of the EGR gas flowing into the fuel reforming cylinder 2 is high, so the bypass amount adjusting valve 75 is closed to bypass the entire amount. On the other hand, under operating conditions where the output of the output cylinder 3 is high, the EGR gas temperature becomes too high, so the bypass amount adjusting valve 75 is released to adjust the inlet gas temperature of the fuel reforming cylinder 2.

As a guideline for the gas temperature, the reformed cylinder inlet gas temperature must exceed at least 400K under the condition that the equivalent ratio is 3.0 or more, and especially under the condition where the target equivalent ratio is high, the reforming cylinder inlet is compared with the condition where the equivalent ratio is low. It is desirable to raise the gas temperature.

Although the embodiments of the present disclosure have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present disclosure is shown not only by the description of the above-described embodiment but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

1 Fuel reforming engine 2 Fuel reforming cylinder 3 Output cylinder 12 Turbocharger 12b Turbine wheel 61 Exhaust passage 71 EGR passage 79 Intake passage

Claims (5)

A fuel reforming cylinder that reforms the supplied fuel,
An output cylinder to which the reformed fuel produced by the reformed fuel is supplied and the engine output is obtained by combustion of the reformed fuel is provided.
A fuel reforming engine in which the intake passage of the fuel reforming cylinder is connected only to the exhaust passage of the output cylinder. The fuel reforming engine according to claim 1, wherein the intake passage of the fuel reforming cylinder is connected to the exhaust passage on the upstream side of the exhaust turbine provided in the exhaust passage of the output cylinder. A means for detecting or estimating the oxygen concentration in the exhaust gas of the exhaust passage of the output cylinder is provided.
Based on the detected or estimated oxygen concentration in the exhaust gas, the fuel supply amount to the fuel reforming cylinder is adjusted so that the equivalent ratio in the fuel reforming cylinder becomes a value of 2.0 to 10.0. The fuel reforming engine according to claim 1 or 2. A means for detecting the amount of exhaust gas introduced from the exhaust passage of the output cylinder to the intake passage of the fuel reforming cylinder, and
A first flow rate control valve for adjusting the amount of exhaust gas is provided.
Any of claims 1 to 3, wherein the first flow control valve is controlled so that the equivalent ratio in the fuel reforming cylinder becomes a value of 2.0 to 10.0 according to the operating conditions of the output cylinder. The fuel reforming engine according to item 1. A heat exchanger provided between the exhaust passage of the output cylinder and the intake passage of the fuel reforming cylinder.
Piping that bypasses the heat exchanger and
A second flow rate control valve for adjusting the amount of exhaust gas flowing into the heat exchanger is provided.
1. The second flow control valve is controlled so that the gas temperature in the fuel reforming cylinder at the time when the piston reaches the compression top dead center in the fuel reforming cylinder becomes a predetermined value. The fuel reforming engine according to any one of the items to 4.

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