Internal combustion engine system and method for controlling an internal combustion engine system

Abstract

Internal combustion engine system, with: an internal combustion engine; a turbocharger that delivers compressed air by using exhaust gas supplied from the internal combustion engine; a reformer that delivers an initial compressed air / fuel mixture obtained through an exothermic reaction between the compressed air and a fuel; a compressed air / fuel mixture generation part that delivers a second compressed air / fuel mixture, which is obtained by mixing the compressed air with the first compressed air / fuel mixture; a temperature acquisition section located between the compressed air / fuel mixture generation section and the internal combustion engine, which achieves a temperature of an air / fuel mixture that corresponds to the second compressed air / fuel mixture flowing between the compressed air / fuel mixture generation section and the internal combustion engine; and a control unit that controls the compressed air / fuel mixture generation unit, wherein the compressed air / fuel mixture generation part comprises the following: a flow ratio matching section configured to receive the compressed air from the turbocharger; and a merging section configured to receive the compressed air from the flow ratio matching section and the first compressed air / fuel mixture from the reformer, and to discharge the second compressed air / fuel mixture, wherein the control part controls the flow ratio adjustment part based on information output by the temperature acquisition part, and wherein the flow ratio matching part adjusts a ratio between a flow rate of compressed air supplied to the merging part and a flow rate of compressed air supplied to the reformer.

Description

Technical field

[0001] The present invention relates to an internal combustion engine system and a method for controlling an internal combustion engine system. State of the art

[0002] An air / fuel mixture, in which the fuel is leaner than the theoretical air / fuel ratio, is supplied to an internal combustion engine. This mixture is then burned in the engine. As a result, the flame temperature during combustion decreases, and nitrogen oxide (NOx) emissions can be reduced. This combustion condition is called lean combustion. When a three-way catalytic converter, used in automobiles or similar vehicles, is used with exhaust gas containing a large amount of oxygen released by lean combustion, the converter's ability to remove nitrogen oxides is reduced. To gain the benefit of lean combustion, it would ultimately be necessary to make the air / fuel mixture so lean that stable driving becomes difficult. When the fuel is lean, the combustion rate decreases.This means that the ignitability of the air / fuel mixture containing fuel and air is reduced. Thermal efficiency decreases with the reduction in ignitability, particularly in a reciprocating engine. To compensate for this, hydrogen can be added to the air / fuel mixture to increase the combustion rate. Hydrogen is produced by a so-called fuel reformer. A fuel reformer uses a catalyst to remove hydrogen from a portion of the fuel supplied to an internal combustion engine. For example, US 4,033,133 A mixes the hydrogen produced by the reformer with air and fuel in a carburetor. The air / fuel mixture is then supplied to the internal combustion engine. DE 10 2012 204 649 A1 and US 2018 / 0 030 907 A1 disclose further prior art. Summary of the invention

[0003] Due to the reduced combustion rate, misfires can occur during lean combustion. Therefore, it is necessary to precisely adjust the fuel supply conditions to the internal combustion engine. Combustion characteristics, such as the combustion rate, are influenced by the temperature of the air / fuel mixture supplied to the engine. For this reason, it is desirable to maintain the air / fuel mixture temperature within a certain range. A typical internal combustion engine operates by drawing in ambient air. Thus, there is a need for a system that enables stable and continuous lean combustion by minimizing the impact of changes in ambient air temperature.

[0004] The object of the present invention is to provide an internal combustion engine system that enables stable and continuous lean combustion, and a method for controlling an internal combustion engine system.

[0005] The above problem is solved by an internal combustion engine system according to claim 1 and by methods for controlling an internal combustion engine system according to claims 7 and 8.

[0006] The internal combustion engine system according to the invention and the methods according to the invention for controlling an internal combustion engine system enable stable and continuous lean combustion. Further advantageous embodiments are disclosed in the dependent claims. Brief description of the drawings Fig. Figure 1 is a diagram representing an internal combustion engine system according to one embodiment. Fig. 2 is a diagram that shows a control sequence through a control part of Fig. 1 represents. Fig. Figure 3 is a diagram representing an internal combustion engine system according to one variation. Fig. Figure 4 is a diagram illustrating a control sequence through a control element of Fig. 3 represents. Description of the embodiments

[0007] An internal combustion engine system according to one aspect of the present disclosure comprises an internal combustion engine, a turbocharger that delivers compressed air by using exhaust gas supplied from the internal combustion engine, a reformer that delivers a first compressed air-fuel mixture obtained by an exothermic reaction between the compressed air and the fuel, and a compressed air-fuel mixture generating section that delivers a second compressed air-fuel mixture obtained by mixing the compressed air with the first compressed air-fuel mixture. The compressed air-fuel mixture generating section comprises a flow-ratio matching section configured to receive the compressed air from the turbocharger and a merging section configured to receive the compressed air from the flow-ratio matching section and the first compressed air-fuel mixture from the reformer and to deliver the second compressed air-fuel mixture.The flow ratio matching section adjusts a ratio between a flow rate of compressed air supplied to the merging section and a flow rate of compressed air supplied to the reformer.

[0008] The reformer produces hydrogen from the fuel through an exothermic reaction. The heat generated is transferred to the compressed air supplied from the turbocharger. The flow-ratio adjustment section adapts the ratio between the flow rate of the compressed air supplied to the aggregation section and the flow rate of the compressed air supplied to the reformer. The temperature of the first compressed air / fuel mixture discharged from the reformer is controlled by adjusting the flow rate of the compressed air supplied to the reformer. Consequently, the temperature of the second compressed air / fuel mixture, in which the first compressed air / fuel mixture is blended with the compressed air, can also be controlled. The air / fuel mixture, controlled to achieve a temperature suitable for ideal lean combustion, can then be supplied to the internal combustion engine.Consequently, good combustion conditions can be achieved in the internal combustion engine. In other words, the internal combustion engine system of the present disclosure enables stable and continuous lean combustion.

[0009] The above internal combustion engine system further comprises a temperature acquisition section, located between the compressed air / fuel mixture generation section and the internal combustion engine, which raises the temperature of the air / fuel mixture flowing between the compressed air / fuel mixture generation section and the internal combustion engine, and a control section that controls the flow ratio adjustment section based on information output from the temperature acquisition section. This configuration allows the temperature of the air / fuel mixture supplied to the internal combustion engine to be brought closer to a target temperature. The temperature of the air / fuel mixture supplied to the internal combustion engine can thus be appropriately controlled.

[0010] In the above internal combustion engine system, the flow-ratio adaptation section can include a branching section configured to receive compressed air from the turbocharger, a first valve connected to the branching section and the merging section and configured to control the flow rate of compressed air supplied to the merging section, and a second valve connected to the branching section and the reformer and configured to control the flow rate of compressed air supplied to the reformer. This configuration allows for more appropriate control of the air / fuel mixture temperature.

[0011] Preferably, if the temperature of the air / fuel mixture is higher than a target temperature, the control unit can reduce the flow rate of the compressed air supplied from the second valve to the reformer. If the temperature of the air / fuel mixture is lower than the target temperature, the control unit can increase the flow rate of the compressed air supplied from the second valve to the reformer. This control allows for even more precise control of the temperature of the air / fuel mixture supplied to the internal combustion engine.

[0012] Preferably, the turbocharger comprises a turbine configured to draw in exhaust gas and generate power, a compressor configured to draw in power and deliver compressed air, a bypass passage configured to connect the internal combustion engine to the turbine and short-circuit a turbine delivery section, and a wastegate valve formed in the bypass passage. The control unit can control the wastegate valve based on the temperature of the air / fuel mixture. The flow rate of the exhaust gas entering the bypass passage influences the turbine output. The turbine output influences the compressor pressure ratio. The compressor pressure ratio influences the temperature of the compressed air delivered from the compressor.The temperature of the compressed air can thus be controlled by regulating the flow rate of the exhaust gas entering the bypass passage using a slide valve. As a result, the temperature of the air / fuel mixture supplied to the internal combustion engine can be controlled to a predetermined temperature.

[0013] In the above internal combustion engine system, the flow-ratio adjustment section can include a branching section configured to receive compressed air from the turbocharger, a first valve connected to the branching section and the merger section and configured to control the flow rate of compressed air supplied to the merger section, and a second valve connected to the branching section and the reformer and configured to control the flow rate of compressed air supplied to the reformer. If the air / fuel mixture temperature is higher than a target temperature, the control section can increase the flow rate of the exhaust gas flowing into the bypass passage, increase the flow rate of compressed air supplied from the first valve to the merger section, and increase the flow rate of compressed air supplied from the second valve to the reformer.If the temperature of the air / fuel mixture is lower than the target temperature, the control unit can reduce the flow rate of the exhaust gas entering the bypass passage, the flow rate of the compressed air supplied from the first valve to the merging section, and the flow rate of the compressed air supplied from the second valve to the reformer. This control allows for more precise control of the temperature of the air / fuel mixture supplied to the internal combustion engine.

[0014] In the above internal combustion engine system, a buffer tank can be provided between the internal combustion engine and the flow ratio matching unit. This configuration is able to reduce the effect of pressure fluctuations from the internal combustion engine.

[0015] Another aspect of the present disclosure is a method for controlling an internal combustion engine system. The internal combustion engine system comprises an internal combustion engine, a turbocharger that delivers compressed air by using exhaust gas supplied from the internal combustion engine, and a reformer that uses the compressed air to generate an initial compressed air / fuel mixture for an air / fuel mixture that is supplied to the internal combustion engine.The method for controlling an internal combustion engine system can include a first step of obtaining a temperature of the air / fuel mixture, a second step of comparing the temperature of the air / fuel mixture with a target temperature, a third step of reducing the flow rate of the compressed air supplied to the reformer if, as a result of the second step, the temperature of the air / fuel mixture is higher than the target temperature, and a fourth step of increasing the flow rate of the compressed air supplied to the reformer if, as a result of the second step, the temperature of the air / fuel mixture is lower than the target temperature.

[0016] The control method described above is capable of supplying the internal combustion engine with an air / fuel mixture that has been controlled to maintain a temperature sufficient for ideal lean combustion. This allows for optimal combustion conditions within the engine. In other words, the method for controlling an internal combustion engine system as disclosed herein enables stable and continuous lean combustion.

[0017] Another aspect of the present disclosure is a method for controlling an internal combustion engine system. The internal combustion engine system comprises an internal combustion engine, a turbocharger that delivers compressed air using exhaust gas supplied from the internal combustion engine, a mechanism for diverting a portion of the exhaust gas, a reformer that generates a first compressed air / fuel mixture using the compressed air, and a compressed air / fuel mixture generating section that, using the compressed air and the first compressed air / fuel mixture, generates a second compressed air / fuel mixture for an air / fuel mixture that is supplied to the internal combustion engine. The mechanism for diverting a portion of the exhaust gas comprises a bypass passage connected upstream of an inlet of the turbocharger and downstream of an outlet of the turbocharger, and a wastegate valve.that is formed in the bypass passage. The method for controlling an internal combustion engine system comprises a first step of obtaining an air / fuel mixture temperature, a second step of comparing the air / fuel mixture temperature with a target temperature, a fifth step of executing a control to increase the flow rate of the redirected exhaust gas, the flow rate of the compressed air supplied to the compressed air / fuel mixture generation section, and the flow rate of the compressed air supplied to the reformer if, as a result of the second step, the air / fuel mixture temperature is higher than the target temperature, and a sixth step of executing a control to decrease the flow rate of the redirected exhaust gas, the flow rate of the compressed air supplied to the compressed air / fuel mixture generation section, and the flow rate of the compressed air.The air supplied to the reformer is released when, as a result of the second step, the temperature of the air / fuel mixture is lower than the target temperature. These steps control the flow rate of the exhaust gas entering the bypass passage via a slide valve. As a result, the temperature of the compressed air can be controlled. The temperature of the air / fuel mixture supplied to the internal combustion engine can thus be controlled to a predetermined temperature.

[0018] Embodiments of an internal combustion engine system and a method for controlling an internal combustion engine system of the present disclosure are described in detail below with reference to the accompanying drawings. Identical elements are given the same reference numerals in the description of the drawings, and redundant explanations are omitted.

[0019] An internal combustion engine system 1, which is in Fig. The system shown in Figure 1 is used as a power source for a generator. The internal combustion engine system 1 is also used as a power source for a mobile object. Examples of the mobile object include a vehicle and a ship. The object that receives power from the internal combustion engine system 1 is unlimited.

[0020] The internal combustion engine system 1 comprises an internal combustion engine 2, a turbocharger 3, a reformer 4, a compressed air / fuel mixture generator 6 (a compressed air / fuel mixture generation unit), and a control unit 7 (a control unit). The internal combustion engine system 1 may include other components.

[0021] The turbocharger 3 is driven by exhaust gas Ga from the internal combustion engine 2. A portion of compressed air A1 (compressed air A1b) supplied from the turbocharger 3 is fed to the reformer 4. This results in the formation of a first compressed air / fuel mixture P1, containing air and hydrogen. The first compressed air / fuel mixture P1 is mixed with fuel F1 in an air / fuel mixture generation unit 19, described below. A gas containing the first compressed air / fuel mixture P1 and fuel F1 is an air / fuel mixture M. The air / fuel mixture M is supplied to the internal combustion engine 2.

[0022] The air / fuel mixture generation section 19 discharges the air / fuel mixture M. The air / fuel-gas ratio of the air / fuel mixture M is leaner than the theoretical air / fuel ratio. This means that burning the air / fuel mixture M results in a lean combustion. The air / fuel mixture M contains the hydrogen produced by the reformer 4. The air / fuel mixture M containing the hydrogen is therefore able to achieve good combustion conditions, even when the air / fuel mixture M has an air / fuel-gas ratio that results in a lean combustion.

[0023] The temperature of the air / fuel mixture M is also important for achieving good combustion conditions. That is, the ratio of the components of the air / fuel mixture M and the temperature of the air / fuel mixture M are controlled to meet predetermined conditions and achieve good combustion. The internal combustion engine system 1 of the present disclosure does not have a thermal control element, such as a heater or a cooler, for adjusting the temperature of the air / fuel mixture M. The internal combustion engine system 1 supplies the air / fuel mixture M, which is controlled to a predetermined temperature, without having a thermal control element. Details of the internal combustion engine system 1 are described below.

[0024] The internal combustion engine 2 has an internal combustion engine inlet 2a and an internal combustion engine outlet 2b. The internal combustion engine inlet 2a receives the air / fuel mixture M. The internal combustion engine inlet 2a is connected to the compressed air / fuel mixture generator 6 via various components. The internal combustion engine outlet 2b releases the exhaust gas Ga. The internal combustion engine outlet 2b is connected to the turbocharger 3.

[0025] The turbocharger 3 has a turbine 8 and a compressor 9. The turbine 8 has a turbine inlet 8a and a turbine outlet 8b. The turbine inlet 8a is connected to the internal combustion engine outlet 2b. The turbine 8 draws in the exhaust gas Ga from the turbine inlet 8a. The turbine 8 generates power to drive the compressor 9. Exhaust gas Gb is discharged from the turbine outlet 8b. The compressor 9 has a compressor inlet 9a and a compressor outlet 9b. The compressor outlet 9b is connected to the compressed air / fuel mixture generator 6. The compressor 9 draws in air A2 at atmospheric pressure from the compressor inlet 9a. The compressor 9 compresses the air A2 using the power supplied by the turbine 8. The compressed air A1 is discharged from the compressor outlet 9b.

[0026] Reformer 4 has a first reformer inlet 4a, a second reformer inlet 4b, and a reformer outlet 4c. The first reformer inlet 4a is connected to the compressed air / fuel mixer 6. The second reformer inlet 4b is connected to a fuel supply section 11. The reformer outlet 4c is connected to the compressed air / fuel mixer 6. Reformer 4 draws in compressed air A1b from the first reformer inlet 4a. Reformer 4 draws in fuel F2 from the second reformer inlet 4b. Reformer 4 causes the compressed air A1b and fuel F2 to react with each other. As a result, hydrogen is produced. In particular, reformer 4 causes the oxygen in the compressed air A1b and the fuel F2 to react catalytically. As a result of this reaction, carbon monoxide and hydrogen are produced. This reaction is exothermic. Reformer 4 discharges the first compressed air / fuel mixture P1 from reformer outlet 4c.The first compressed air / fuel mixture P1 contains compressed air and hydrogen. It should be noted that, if appropriate, the reformer 4 may use a device capable of generating hydrogen through an exothermic reaction.

[0027] The compressed air / fuel mixture generator 6 has a first generator inlet 6a, a first generator outlet 6b, a second generator inlet 6c, and a second generator outlet 6d. The first generator inlet 6a is connected to the compressor outlet 9b. The first generator outlet 6b is connected to the first reformer inlet 4a. The second generator inlet 6c is connected to the reformer outlet 4c. The second generator outlet 6d is connected to the internal combustion engine inlet 2a via various components.

[0028] The compressed air / fuel mixture generator 6 receives compressed air A1 from the first generator inlet 6a. The compressed air / fuel mixture generator 6 discharges compressed air A1b from the first generator outlet 6b. The compressed air / fuel mixture generator 6 receives the first compressed air / fuel mixture P1 from the second generator inlet 6c. The compressed air / fuel mixture generator 6 discharges a second compressed air / fuel mixture P2 from the second generator outlet 6d.

[0029] The compressed air / fuel mixer 6 has a branch section 12, a first valve 13, a second valve 14, and a merging section 16. The branch section 12 is connected to the first mixer inlet 6a. The branch section 12 is connected upstream of the first valve 13. The branch section 12 is connected upstream of the second valve 14. The first valve 13 is connected to the branch section 12. The first valve 13 is connected to the merging section 16. The second valve 14 is connected to the branch section 12. The second valve 14 is connected to the first mixer outlet 6b. The merging section 16 is connected to the first valve 13. The merging section 16 is connected to the second mixer inlet 6c. The merging section 16 is connected to the second producer outlet 6d.

[0030] The branching section 12 distributes the compressed air A1 between the first valve 13 and the second valve 14. The first valve 13 controls the flow rate of the compressed air A1a flowing from the branching section 12 to the merging section 16. The second valve 14 controls the flow rate of the compressed air A1b flowing from the branching section 12 to the first generator outlet 6b. The second valve 14 controls the flow rate of the compressed air A1b supplied to the reformer 4. The first valve 13 and the second valve 14 adjust the ratio between the flow rate of the compressed air A1a supplied to the merging section 16 and the flow rate of the compressed air A1b supplied to the reformer 4. The branching section 12, the first valve, and the second valve 14 form a flow ratio matching section 17.The merging part 16 mixes the first compressed air / fuel mixture P1, which is taken in from the second generator inlet 6c, with a portion of the compressed air A1, which is the compressed air A1a, which is supplied via the first valve 13 from the branching part 12.

[0031] The internal combustion engine system 1 comprises an expansion tank 18, the air / fuel mixture generation unit 19, and a temperature sensor 21. The expansion tank 18, the air / fuel mixture generation unit 19, and the temperature sensor 21 are arranged between the compressed air / fuel mixture generator 6 and the internal combustion engine 2. In the Fig. In the example shown, the expansion tank 18, the air / fuel mixture generator 19, and the temperature sensor 21 are arranged in sequence along a single direction from the compressed air / fuel mixture generator 6 to the internal combustion engine 2. The expansion tank 18 suppresses the upstream transmission of the effects of pressure fluctuations in the internal combustion engine 2. That is, the expansion tank 18 suppresses the transmission of the effects of pressure fluctuations in the internal combustion engine 2 to the compressed air / fuel mixture generator 6. It should be noted that the expansion tank 18 can be provided if required. The expansion tank 18 can be omitted. The air / fuel mixture generator 19 receives the second compressed air / fuel mixture P2 and fuel F1. The air / fuel mixture generation unit 19 generates the air / fuel mixture M. The temperature sensor 21 obtains a gas temperature (Tin) of the air / fuel mixture M.The temperature sensor 21 obtains the gas temperature (Tin) of a gas flowing into the internal combustion engine inlet 2a.

[0032] The internal combustion engine system 1 includes the control device 7. The control device 7 controls the gas temperature (Tin) of the air / fuel mixture M, which is supplied to the internal combustion engine inlet 2a, to a target temperature (Ttr). This control device has a first mode and a second mode. The first mode maintains the gas temperature (Tin) at the target temperature (Ttr). The second mode brings the gas temperature (Tin) closer to the target temperature (Ttr). The gas temperature (Tin) is controlled by the operation of the compressed air / fuel mixer 6. The control device 7 controls the operation of the compressed air / fuel mixer 6. As a result, the air / fuel mixture M is produced at the target temperature (Ttr).

[0033] The control unit 7 generates a control signal based on temperature information. This control signal is used to control the compressed air / fuel mixer 6. The control unit 7 comprises a temperature acquisition section 7a, a temperature comparison section 7b, and a control signal generation section 7c as functional elements. These elements are described in detail below when describing the control function performed by the control unit 7.

[0034] The control unit 7 controls the flow rate of the compressed air A1a. The compressed air A1a is supplied from the branching section 12 to the merging section 16. The control unit 7 controls the flow rate of the compressed air A1a by adjusting the opening degree of the first valve 13. The control unit 7 also controls the flow rate of the compressed air A1b. The compressed air A1b is supplied from the branching section 12 to the reformer 4. The control unit 7 controls the flow rate of the compressed air A1b by adjusting the opening degree of the second valve 14. The control unit 7 generates a control signal φ1, which is to be provided to the first valve 13, and a control signal φ2, which is to be provided to the second valve 14. The control unit 7 provides the control signal φ1 to the first valve 13. The control device 7 provides the control signal φ2 to the second valve 14.The specific operation of the control unit 7 is described below.

[0035] The control unit 7 includes, as hardware, for example, any suitable processor such as a central processing unit (CPU) or specialized processors (for example, a digital signal processor (DSP)) for different tasks. The control unit 7 may, if necessary, include non-writable memory (ROM) or read / write memory (RAM) to perform processing.

[0036] A method for controlling the internal combustion engine system 1 is carried out by the control device 7. The control carried out by the control device 7 is described in detail below with reference to the flowchart of Fig. 2 described.

[0037] The control unit 7 obtains the gas temperature (Tin) (step S1: first step). Step S1 is performed by the temperature sensor 21 and the temperature acquisition unit 7a.

[0038] Next, the control unit 7 compares the gas temperature (Tin) with the target temperature (Ttr) (step S2: second step). Step S2 is performed by the temperature comparison unit 7b. In step S2, it is determined whether the gas temperature (Tin) is higher than the target temperature (Ttr). Step S2 can also determine whether the gas temperature (Tin) is lower than the target temperature (Ttr).

[0039] If the gas temperature (Tin) is higher than the target temperature (Ttr) (step S2: YES), the control unit 7 controls the compressed air / fuel mixer 6 to lower the gas temperature (Tin). The gas temperature (Tin) can be controlled by the temperature (T2) of the first compressed air / fuel mixture P1, which is delivered from the reformer 4. The temperature (T2) of the first compressed air / fuel mixture P1 is higher than the temperature (T1) of the compressed air A1a (T2>T1). The compressed air A1a flows from the branching section 12 through the first valve 13 to the merging section 16.

[0040] The temperature (T2) of the first compressed air / fuel mixture P1 can be controlled by the flow rate of the compressed air A1b supplied to the reformer 4. The control device 7 reduces the flow rate of the compressed air A1b (third step). The compressed air A1b is supplied to the reformer 4. In particular, the control device 7 reduces the opening degree of the second valve 14 (step S3). For the flow rate and pressure of the second compressed air / fuel mixture P2, which is delivered from the compressed air / fuel mixer 6, it is necessary to maintain predetermined conditions. If the flow rate of the compressed air A1b supplied to the reformer 4 is reduced, the control device 7 increases the flow rate of the compressed air A1a to maintain these conditions. The compressed air A1a is supplied to the merging section 16 from the branching section 12.In particular, the control device 7 increases the opening degree of the first valve (step S4). That is, the third step has steps S3 and S4.

[0041] If the gas temperature (Tin) is lower than the target temperature (Ttr) (Step S2: NO), the control unit 7 controls the compressed air / fuel mixer 6 to raise the gas temperature (Tin). The control unit 7 increases the flow rate of the compressed air A1b (Fourth Step). The compressed air A1b is supplied to the reformer 4. Specifically, the control unit 7 increases the opening degree of the second valve 14 (Step S5). Furthermore, the control unit 7 decreases the flow rate of the compressed air A1a supplied to the merging section 16 from the branching section 12. Specifically, the control unit 7 decreases the opening degree of the first valve (Step S6). That is, the fourth step comprises Step S5 and Step S6.

[0042] Of the two passages from the branching section 12 to the merging section 16, the pressure drop in the passage containing the first valve 13 is greater than the pressure drop in the passage containing the second valve 14. This means the total pressure drop is set to a predetermined level. This setting reduces the pressure differential between the pressure of the compressed air A1a and the pressure of the first compressed air-fuel mixture P1. The compressed air A1a is supplied from the first valve 13. The first compressed air / fuel mixture P1 is supplied from the reformer 4. The compressed air A1a and the first compressed air / fuel mixture P1 can thus be properly combined at the merging section 16.

[0043] The control unit 7 then executes step S1 again. In other words, the control unit 7 repeats the above control during operation of the internal combustion engine system 1.

[0044] The operation and effects of the internal combustion engine system 1 according to the present disclosure will now be described.

[0045] Reformer 4 causes hydrogen to be produced from fuel F2 through an exothermic reaction. The heat generated is transferred to the compressed air A1b supplied from turbocharger 3. The temperature (T1) of the first compressed air / fuel mixture P1 discharged from reformer 4 is controlled by adjusting the flow rate of the compressed air A1b supplied to reformer 4. This, in turn, allows for the control of the temperature (T3) of the second compressed air / fuel mixture P2, in which the first compressed air / fuel mixture P1 is mixed with compressed air A1a. The resulting air / fuel mixture M, controlled to achieve an ideal lean-burn combustion temperature, is then supplied to the internal combustion engine 2. Consequently, optimal combustion conditions can be achieved in the internal combustion engine 2, resulting in improved exhaust gas characteristics.

[0046] Internal combustion engine system 1 does not require a cooling or heating device to control the gas temperature (Tin). Therefore, internal combustion engine system 1 can have a simple configuration. Exhaust gas temperature can be used for control instead of gas temperature (Tin). Information about the oxygen concentration of the exhaust gas can also be used for control. A control system that uses oxygen concentration information is capable of detecting misfires. As a result, a control system can be achieved that contributes to stable driving.

[0047] The internal combustion engine system 1 according to the present disclosure can be applied to a device that requires a comparatively constant output from the internal combustion engine 2. In this case, the fluctuation in the airflow rate is small, which allows for good control. For example, a generator has a small output fluctuation and operates in a steady state. The internal combustion engine system 1 can be appropriately used for a generator. There is also a device in which the temperature of the air / fuel mixture changes continuously during starting until a steady state is reached. The internal combustion engine system 1 according to the present disclosure can be appropriately used for a device that repeatedly starts and stops, such as an emergency generator.

[0048] Although the internal combustion engine system and method for controlling an internal combustion engine system of the present disclosure have been described above, they are not limited to the embodiments described above. The internal combustion engine system and method for controlling an internal combustion engine system of the present disclosure can be implemented in a variety of ways.

[0049] As in Fig. As shown in Figure 3, an internal combustion engine system 1A, according to one variation, has a turbocharger 3A instead of the turbocharger 3. In addition to the control signals φ1 and φ2, the control device 7 also outputs a control signal φ3. Other configurations of the internal combustion engine system 1A are the same as those of the internal combustion engine system 1, and a detailed explanation of these is omitted.

[0050] The turbocharger 3A has a so-called wastegate valve (hereinafter referred to as "wastegate valve 22"). The wastegate valve 22 is integrated into a bypass passage 23. The bypass passage 23 restricts the flow of a portion of the exhaust gas Ga from the internal combustion engine 2 into the turbine 8. The bypass passage 23 directs a portion of the exhaust gas Ga to the turbine outlet 8b. The wastegate valve 22 and the bypass passage 23 divert a portion of the exhaust gas Ga. This configuration allows the flow rate of the exhaust gas Ga supplied to the turbine 8 to be controlled. The balance between the power generated by the turbine 8 and the power required by the compressor 9 can thus be adjusted. The internal combustion engine system 1A, which includes the turbocharger 3A, can also be used for a device that focuses on so-called starting characteristics (for example, a vehicle).

[0051] One end of the bypass passage 23 is connected to an upstream branch section 24. The upstream branch section 24 is formed as a passage that connects the internal combustion engine outlet 2b to the turbine inlet 8a. The other end of the bypass passage 23 is connected to a downstream branch section 27. The downstream branch section 27 is formed as a discharge passage 26 (discharge section), which is connected to the turbine outlet 8b. The wastegate valve 22 is connected to the bypass passage 23 between the upstream branch section 24 and the downstream branch section 27. The wastegate valve 22 controls an exhaust gas flow rate Gc. The exhaust gas Gc flows from the upstream branch section 24 to the downstream branch section 27. Control of the wastegate valve 22 is based on the control signal φ3, which is provided by the control device 7.

[0052] The control unit 7 controls the opening degree of the wastegate valve 22 based on the gas temperature (Tin). For example, if, as in Fig.As shown in Figure 4, if the gas temperature (Tin) is higher than the target temperature (Ttr) (Step S2: YES), the control device 7 increases the flow rate of the redirected exhaust gas Gc. The control device 7 also increases the flow rate of the compressed air A1a supplied to the merging section 16 of the compressed air / fuel mixer 6. Furthermore, the control device 7 increases the flow rate of the compressed air A1b supplied to the reformer 4. These three controls constitute a fifth step. Specifically, the control device 7 increases the opening degree of the wastegate valve 22 (Step S6). When the opening degree of the wastegate valve 22 is increased, a greater amount of exhaust gas G flows into the bypass passage 23, and the flow rate of the exhaust gas Ga supplied to the turbine 8 is reduced. As a result, the power generated at the turbine 8 is reduced. In other words, the pressure ratio of compressor 9 is reduced.The temperature of the compressed air A1, which is discharged from the compressor outlet 9b, is thus reduced. It should be noted that in this case, the opening degree of the first valve 13 and the opening degree of the second valve 14 can be increased to obtain the air / fuel mixture M at a predetermined pressure (step S7). That is, the fifth step comprises steps S6 and S7.

[0053] If the gas temperature (Tin) is lower than the target temperature (Ttr), the control device 7 reduces the flow rate of the redirected exhaust gas Gc. The control device 7 also reduces the flow rate of the compressed air A1a supplied to the merging section 16 of the compressed air / fuel mixer 6. Furthermore, the control device 7 reduces the flow rate of the compressed air A1b supplied to the reformer 4. These three controls constitute a sixth step. Specifically, the control device 7 reduces the opening degree of the wastegate valve 22 (step S8). When the opening degree of the wastegate valve 22 is reduced, an increased amount of exhaust gas Ga flows into the turbine 8. As a result, the power generated at the turbine 8 is increased, and the pressure ratio of the compressor 9 is increased. The temperature of the compressed air A1, which is discharged from compressor outlet 9b, is thus increased.It should be noted that in this case, the opening degree of the first valve 13 and the opening degree of the second valve 14 can be reduced to obtain the air / fuel mixture M at a predetermined pressure (step S9). That is, the sixth step comprises steps S8 and S9.

[0054] The first valve 13 can be connected to the turbocharger 3 and the branching section 12. The second valve 14 can be connected to the reformer 4 and the merging section 16. Reference symbol list 1, 1A Internal combustion engine system 2 Internal combustion engine 2a Internal combustion engine inlet 2b Internal combustion engine exhaust 3, 3A Turbocharger 4 Reformers 4a First Reformer Admission 4b Second Reformer Entrance 4c Reformer outlet 6 Compressed air / fuel mixture generator (compressed air / fuel mixture generation unit) 6a First producer entry 6b First producer outlet 6c Second producer entrance 6d Second producer outlet 7 Control unit (control part) 7a Temperature acquisition section 7b Temperature comparison section 7c Control signal generation section 8 Turbine 8a Turbine inlet 8b Turbine outlet 9 compressors 9a Compressor inlet 9b Compressor outlet 11 Fuel supply section 12 Branching section 13 First valve 14 Second valve 16 Merger section 17 Flow ratio adjustment section 18 expansion tanks 19 Air / fuel mixture generation section 21 Temperature sensor (temperature sensing unit) 22 Wastegate valve 23 Bypass passage 24 Upstream branch section 26th submission round 27 Downstream branch section A1, A1a, A1b Compressed air A2 Air F1, F2 fuel G, Ga exhaust gas P1 First compressed air / fuel mixture P2 Second compressed air / fuel mixture M air / fuel mixture φ1, φ2, φ3 Control signal

Claims

Internal combustion engine system, comprising: an internal combustion engine; a turbocharger that delivers compressed air by using exhaust gas supplied from the internal combustion engine; a reformer that delivers a first compressed air / fuel mixture obtained by an exothermic reaction between the compressed air and a fuel; a compressed air / fuel mixture generating section that delivers a second compressed air / fuel mixture obtained by mixing the compressed air with the first compressed air / fuel mixture; a temperature acquisition section arranged between the compressed air / fuel mixture generating section and the internal combustion engine, which achieves a temperature of an air / fuel mixture corresponding to the second compressed air / fuel mixture flowing between the compressed air / fuel mixture generating section and the internal combustion engine;and a control section that controls the compressed air / fuel mixture generation section, wherein the compressed air / fuel mixture generation section comprises: a flow ratio matching section configured to receive compressed air from the turbocharger; and a merging section configured to receive compressed air from the flow ratio matching section and the first compressed air / fuel mixture from the reformer and to discharge the second compressed air / fuel mixture, wherein the control section controls the flow ratio matching section based on information output by the temperature acquisition section, and wherein the flow ratio matching section adjusts a ratio between a flow rate of compressed air supplied to the merging section and a flow rate of compressed air supplied to the reformer. Internal combustion engine system according to claim 1, wherein the flow ratio matching part comprises: a branching part configured to receive the compressed air from the turbocharger; a first valve connected to the branching part and the merging part and configured to control the flow rate of the compressed air supplied to the merging part; and a second valve connected to the branching part and the reformer and configured to control the flow rate of the compressed air supplied to the reformer. Internal combustion engine system according to claim 2, wherein the control part reduces the flow rate of the compressed air supplied to the reformer from the second valve when the temperature of the air / fuel mixture is higher than a target temperature, and the control part increases the flow rate of the compressed air supplied to the reformer from the second valve when the temperature of the air / fuel mixture is lower than the target temperature. Internal combustion engine system according to claim 1 or 2, wherein the turbocharger comprises: a turbine configured to receive exhaust gas and generate power, a compressor configured to receive power and deliver compressed air, a bypass passage configured to short-circuit a passage connecting the internal combustion engine to the turbine and a delivery portion of the turbine, and a wastegate valve formed in the bypass passage, wherein the control part controls the wastegate valve based on the temperature of the air / fuel mixture. Internal combustion engine system according to claim 4, wherein the flow ratio matching part comprises: a branching part configured to receive the compressed air from the turbocharger; a first valve connected to the branching part and the merging part and configured to control the flow rate of the compressed air supplied to the merging part;and a second valve connected to the branching section and the reformer and configured to control the flow rate of compressed air supplied to the reformer, wherein the control section increases the flow rate of exhaust gas flowing into the bypass passage, increases the flow rate of compressed air supplied to the merging section from the first valve, and increases the flow rate of compressed air supplied to the reformer from the second valve when the temperature of the air / fuel mixture is higher than a target temperature, and the control section decreases the flow rate of exhaust gas flowing into the bypass passage, decreases the flow rate of compressed air supplied to the merging section from the first valve, and decreases the flow rate of compressed air supplied to the reformer from the second valve when the temperature of the air / fuel mixture is lower than the target temperature. Internal combustion engine system according to one of claims 1 to 5, wherein a compensating reservoir is provided between the internal combustion engine and the flow ratio matching part. A method for controlling an internal combustion engine system comprising an internal combustion engine, a turbocharger that delivers compressed air using exhaust gas supplied from the internal combustion engine, and a reformer that uses the compressed air to generate a first compressed air / fuel mixture for an air / fuel mixture supplied to the internal combustion engine, the method comprising: a first step of obtaining a temperature of the air / fuel mixture; a second step of comparing the temperature of the air / fuel mixture with a target temperature; a third step of reducing a flow rate of the compressed air supplied to the reformer if, as a result of the second step, the temperature of the air / fuel mixture is higher than the target temperature;and a fourth step: increasing the flow rate of the compressed air supplied to the reformer if, as a result of the second step, the temperature of the air / fuel mixture is lower than the target temperature. A method for controlling an internal combustion engine system, wherein the internal combustion engine system comprises an internal combustion engine, a turbocharger that delivers compressed air by using exhaust gas supplied from the internal combustion engine, a mechanism for diverting a portion of the exhaust gas, a reformer that generates a first compressed air / fuel mixture by using the compressed air, and a compressed air / fuel mixture generating section that, using the compressed air and the first compressed air / fuel mixture, generates a second compressed air / fuel mixture for an air / fuel mixture supplied to the internal combustion engine, wherein the mechanism for diverting a portion of the exhaust gas comprises a bypass passage connected upstream of an inlet of the turbocharger and downstream of an outlet of the turbocharger, and a wastegate valve formed in the bypass passage.wherein the method comprises: a first step of obtaining a temperature of the air / fuel mixture; a second step of comparing the temperature of the air / fuel mixture with a target temperature; a fifth step of executing a control to increase a flow rate of the redirected exhaust gas, a flow rate of the compressed air supplied to the compressed air / fuel mixture generating section, and a flow rate of the compressed air supplied to the reformer, if, as a result of the second step, the temperature of the air / fuel mixture is higher than the target temperature; and a sixth step of executing a control to decrease the flow rate of the redirected exhaust gas, the flow rate of the compressed air supplied to the compressed air / fuel mixture generating section, and the flow rate of the compressed air supplied to the reformer.if, as a result of the second step, the temperature of the air / fuel mixture is lower than the target temperature.

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