Engine systems and series hybrid vehicles

Abstract

To achieve both reduction in cooling loss and reduction in exhaust loss according to a load on a rotary engine.SOLUTION: An engine system 12 comprises: a rotary engine 14 having a rotor housing 16, side housings 18, a rotor 20 that is housed in a rotor accommodation chamber surrounded by the rotor housing and the side housings and forms three working chambers 24, and an intake passage 32 for leading air into the working chamber; an EGR passage 46 for recirculating exhaust gas of the rotary engine to the intake passage; an EGR valve 50 for adjusting the amount of exhaust gas to be recirculated to the intake passage; an ECM 70 configured to control the opening degree of the EGR valve. When a load on the rotary engine is relatively high at the same engine rotation speed, the ECM 70 controls the EGR valve such that the EGR rate of intake air introduced into the working chamber becomes high as compared with that when a load on the rotary engine is relatively low.SELECTED DRAWING: Figure 16

Description

Technical Field

[0005]

[0001] The present invention relates to an engine system and a series hybrid vehicle, and more particularly to an engine system provided with a rotary engine and a series hybrid vehicle.

Background Art

[0002] Conventionally, a rotary engine having a rotor housing, a side housing, and a rotor housed in a rotor housing surrounded by these housings is known. For example, in Patent Document 1, in the combustion stroke of a rotary engine, due to the rotation of the rotor, a strong squish flow flows from the trailing side (the delayed side, that is, the rear side in the rotor rotation direction) to the leading side (the advancing side, that is, the front side in the rotor rotation direction) in the combustion chamber, so it is disclosed that a combustion delay of the air-fuel mixture on the trailing side occurs.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To achieve the above objective, the engine system according to the present invention comprises a rotor housing, a side housing, a rotor housed in a rotor housing chamber surrounded by the rotor housing and the side housing, forming three working chambers, and an intake passage for guiding air into the working chambers. An injector that injects fuel into one of the working chambers, A rotary engine having a rotary engine, an EGR passage for recirculating exhaust gas from the rotary engine into the intake passage, an EGR valve for adjusting the amount of exhaust gas recirculated into the intake passage, and a controller configured to control the opening degree of the EGR valve. A rotational speed sensor that detects the engine speed of a rotary engine, The controller is equipped with such a system, and controls the EGR valve so that, at the same engine speed, when the rotary engine load is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the rotary engine load is relatively low. The controller is configured to control fuel injection by the injectors, and when the engine speed is below the first rotational speed, it controls the injectors so that the number of fuel injections in each combustion cycle of the working chamber is greater than when the engine speed is above the first rotational speed, and the timing of the end of the final fuel injection is delayed. do. With the present invention configured in this way, when the engine load is relatively high, the proportion of second-stage combustion can be increased compared to when the engine load is relatively low, thereby slowing down the pressure rise due to the main combustion and reducing cooling losses. When the engine speed is relatively low, that is, when the airflow in the working chamber is relatively weak, increasing the number of fuel injections in each combustion cycle in the working chamber and retarding the timing of the final fuel injection allows for even distribution of fuel from the leading side to the trailing side, even with weak airflow in the working chamber, thereby obtaining a homogeneous mixture and enabling more precise adjustment of the ratio between the main combustion and the second-stage combustion according to the EGR rate.

[0007] Furthermore, the present invention evening The engine system is A rotary engine comprising a rotor housing, side housings, a rotor housed in a rotor housing chamber surrounded by the rotor housing and side housings and forming three working chambers, and an intake passage for guiding air into the working chambers; an EGR passage for recirculating exhaust gas from the rotary engine into the intake passage; an EGR valve for adjusting the amount of exhaust gas recirculated into the intake passage; and a controller configured to control the opening degree of the EGR valve, wherein the controller controls the EGR valve such that, at the same engine speed, when the load on the rotary engine is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the load on the rotary engine is relatively low; and the controller controls the EGR valve such that, at the same engine speed, the higher the load on the rotary engine, the higher the EGR rate and the smaller the rate of increase in the EGR rate. . According to the present invention configured in this manner, When the engine load is relatively high, the proportion of second-stage combustion can be increased compared to when the engine load is relatively low, thereby slowing down the pressure rise due to the main combustion and reducing cooling losses. In addition, as the engine load increases, the increase in the EGR rate is suppressed, which prevents excessive exhaust losses caused by the late-timing second-stage combustion.

[0008] Furthermore, the present invention Engine system teeth, A rotary engine comprising a rotor housing, side housings, a rotor housed in a rotor housing chamber surrounded by the rotor housing and side housings and forming three working chambers, an intake passage for guiding air into the working chambers, and an injector for injecting fuel into one of the working chambers; an EGR passage for recirculating exhaust gas from the rotary engine into the intake passage; an EGR valve for adjusting the amount of exhaust gas recirculated into the intake passage; a controller configured to control the opening degree of the EGR valve; and a rotational speed sensor for detecting the engine speed of the rotary engine, wherein the controller controls the EGR valve so that, at the same engine speed, when the load on the rotary engine is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the load on the rotary engine is relatively low, and the controller is configured to control fuel injection by the injector, wherein when the engine speed is 1 or less, the injector is controlled so that the number of fuel injections in each combustion cycle of the working chamber is greater and the timing of the end of the last fuel injection is delayed compared to when the engine speed is higher than 1. The controller controls the EGR valve such that, at the same engine speed, the EGR rate increases as the rotary engine load increases, and the rate of increase in the EGR rate decreases. According to the present invention configured in this manner, When the engine load is relatively high, the proportion of second-stage combustion can be increased compared to when the engine load is relatively low, thereby slowing down the pressure rise due to the main combustion and reducing cooling losses. Furthermore, when the engine speed is relatively low, i.e., when the airflow in the working chamber is relatively weak, increasing the number of fuel injections in each combustion cycle in the working chamber and retarding the timing of the final fuel injection allows for even fuel distribution from the leading side to the trailing side, even with weak airflow in the working chamber, resulting in a homogeneous mixture. This allows for more precise adjustment of the ratio of main combustion to second-stage combustion according to the EGR rate. As engine load increases, the increase in the EGR rate is suppressed, thus preventing excessive exhaust losses caused by the late-timing second-stage combustion.

[0009] In other words, the present invention relates to a series hybrid vehicle comprising an electric motor as a driving force source and a generator capable of supplying power to the electric motor, wherein the engine system described above is provided, and the rotary engine drives the generator. In series hybrid vehicles, where the driving force of the rotary engine is used solely to drive the generator, the rotary engine tends to operate in a region of high thermal efficiency, that is, a region of relatively high engine load. Therefore, the engine system according to the present invention, which can reduce cooling losses when the engine load is relatively high, is suitable for series hybrid vehicles. [Effects of the Invention]

[0010] According to the engine system and series hybrid vehicle of the present invention, it is possible to achieve both a reduction in cooling loss and a reduction in exhaust loss depending on the load on the rotary engine. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing the configuration of a series hybrid vehicle according to an embodiment of the present invention. [Figure 2] This is a diagram showing the configuration of an engine system according to an embodiment of the present invention. [Figure 3] This is a control block diagram of a series hybrid vehicle according to an embodiment of the present invention. [Figure 4] This is a flowchart of the engine control process according to an embodiment of the present invention. [Figure 5] This is a flowchart of the engine start control process according to an embodiment of the present invention. [Figure 6] This map shows the relationship between water temperature and required rotational speed in engine starting control according to an embodiment of the present invention. [Figure 7] A map showing the relationship between the coolant temperature and the rotational speed increase rate in engine startup control according to an embodiment of the present invention. [Figure 8] A map showing the relationship between the coolant temperature and the oil introduction amount at startup in engine startup control according to an embodiment of the present invention. [Figure 9] A flowchart of a combustion control process according to an embodiment of the present invention. [Figure 10] A chart exemplifying the pattern of fuel injection timing according to the engine speed in combustion control according to an embodiment of the present invention. [Figure 11] A table showing the relationship between the engine speed and the number of fuel injections in combustion control according to an embodiment of the present invention. [Figure 12] A map showing the relationship between the engine speed and the fuel injection end timing in combustion control according to an embodiment of the present invention. [Figure 13] A map showing the relationship between the engine load and the split ratio of the fuel injection amount in combustion control according to an embodiment of the present invention. [Figure 14] A graph showing the relationship between the eccentric shaft angle and the heat generation rate in a rotary engine. [Figure 15] A graph showing the relationship between the EGR rate and the ratio of the second-stage combustion in a rotary engine. [Figure 16] A map showing the relationship between the engine load and the EGR rate in combustion control according to an embodiment of the present invention. [Figure 17] A map showing the relationship between the engine speed and the EGR rate in combustion control according to an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] <System Configuration> First, the configuration of the series hybrid vehicle and engine system according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is a diagram of the series hybrid vehicle, and Figure 2 is a diagram of the engine system.

[0014] As shown in Figure 1, the series hybrid vehicle 1 includes an electric motor 6, which is a driving force source that drives the drive wheels 4 (front wheels in the example shown) via a reduction gear 2, and a battery 8 and a starter generator 10 that can supply power to the electric motor 6. The series hybrid vehicle 1 also includes an engine system 12 having a rotary engine 14. The starter generator 10 generates electricity when driven by the rotary engine 14 and supplies power to the electric motor 6 and battery 8, and drives the rotary engine 14 with power supplied from the battery 8 when starting the rotary engine 14.

[0015] As shown in Figure 2, the engine system 12 includes a rotary engine 14. The rotary engine 14 includes a rotor housing 16 having a trochoidal inner surface, side housings 18 having planar inner surfaces located on both sides of the rotor housing 16, and a rotor 20 housed in a rotor housing chamber surrounded by the rotor housing 16 and the side housings 18.

[0016] The rotor 20 is supported by an internal eccentric shaft 22 and rotates eccentrically with the eccentric shaft 22. Three working chambers 24 are formed around the rotor 20, enclosed by the rotor housing 16, the side housings 18, and the rotor 20. The volume of each working chamber 24 changes with the eccentric rotation of the rotor 20. Through a series of strokes in the working chambers 24—intake, compression, expansion (explosion), and exhaust—the rotor 20 and the eccentric shaft 22 are rotated, and this rotational force is output as power from the eccentric shaft 22 to the starter generator 10 via a drive shaft (not shown), etc.

[0017] As shown in Figure 2, a spark plug 26 is mounted on the rotor housing 16, and an intake port 28 and an exhaust port 30 are formed in the side housing 18. An intake passage 32 is connected to the intake port 28, and air is introduced into the working chamber 24 through this intake passage 32. An exhaust passage 34 is connected to the exhaust port 30, and exhaust gas from the working chamber 24 is discharged through this exhaust passage 34. The rotor 20 rotates clockwise in Figure 2, and in the state shown in Figure 2, the compression stroke is performed in the upper right working chamber 24 of the rotor 20, and the expansion (explosion) stroke is performed in the lower right working chamber 24. In the example shown in Figure 2, the rotor 20 rotates clockwise, so the leading side of the working chamber 24 is the clockwise side of the working chamber 24 (i.e., the lower right side in the working chamber 24 on the upper right of the rotor 20, and the lower left side in the working chamber 24 on the lower right), and the trailing side is the counterclockwise side of the working chamber 24 (i.e., the upper left side in the working chamber 24 on the upper right of the rotor 20, and the upper right side in the working chamber 24 on the lower right).

[0018] As shown in Figure 2, a throttle valve 36, a throttle opening sensor 38, and an airflow sensor 40 are provided upstream of the intake passage 32, and an air cleaner 42 is provided further upstream. Downstream of the exhaust passage 34, an EGR device 44 and an exhaust gas purification catalyst (not shown) are provided for recirculating a portion of the exhaust gas in the exhaust passage 34 back into the intake passage 32. The EGR device 44 includes an EGR passage 46 connecting the exhaust passage 34 and the intake passage 32, an EGR cooler 48 that cools the recirculating exhaust gas in the EGR passage 46 to increase its density, and an EGR valve 50 and an EGR valve opening sensor 52 for controlling the EGR rate (the ratio of the amount of burned gas to the total amount of gas flowing into the working chamber 24 during the intake stroke).

[0019] The rotor housing 16 is also fitted with an injector 54 that injects fuel into the working chamber 24 and a metering oil pump 56 that injects oil onto the inner surface of the rotor housing 16. The injector 54 is connected to a fuel tank (neither of which is shown) via a fuel supply passage, and fuel is supplied from this fuel tank. The metering oil pump 56 is, for example, an electromagnetically operated oil pump that measures oil taken from an oil gallery (not shown) and injects the required amount of oil onto the inner surface of the rotor housing 16 from an oil nozzle (not shown).

[0020] Furthermore, the rotary engine 14 is equipped with an eccentric shaft angle sensor 58 that detects the rotation angle of the eccentric shaft 22. From the rotation angle detected by the eccentric shaft angle sensor 58, the rotation speed of the eccentric shaft 22, and thus the engine speed of the rotary engine 14, can be detected. Therefore, the eccentric shaft angle sensor 58 corresponds to the "rotation speed sensor" in this invention. In addition, the intake passage 32 is provided with an intake pressure sensor 60 that detects the intake air pressure in the intake passage 32 and an intake air temperature sensor 62 that detects the intake air temperature. Furthermore, although not shown in Figure 2, the rotary engine 14 is also equipped with a water temperature sensor 64 that detects the temperature of the engine coolant (water temperature).

[0021] The engine system 12 includes an ECM (Electronic Control Module) 70, which serves as a computing and control device for controlling the rotary engine 14. The ECM 70 is a well-known microcomputer-based controller. The ECM 70 is composed of a computer that includes one or more processors (typically CPUs) 72, a storage unit (ROM, RAM, etc.) 74 for storing various programs, and so on. The ECM 70 is an example of a "controller" in this invention.

[0022] The ECM70 calculates the control amounts for each device of the rotary engine 14, such as the spark plug 26, injector 54, metering oil pump 56, throttle valve 36, and EGR valve 50, based on signals input from the various sensors 38, 40, 52, 58, 60, 62, and 64 described above, as well as the PCM (Powertrain Control Module) 84 described later, and outputs electrical signals corresponding to the calculated control amounts to those devices. The PCM84 is a controller that controls the entire powertrain of the series hybrid vehicle 1, including the electric motor 6, starter generator 10, engine system 12, reduction gear 2, and battery 8, and is composed of a computer equipped with one or more processors (typically CPUs), a memory unit for storing various programs (ROM, RAM, etc.). The PCM84 is an example of a "controller" in the present invention.

[0023] <Overview of Engine Control> Next, with reference to Figure 3, an overview of the engine control in the series hybrid vehicle 1 according to this embodiment will be described. Figure 3 is a control block diagram of the series hybrid vehicle according to this embodiment.

[0024] The battery 8 of the series hybrid vehicle 1 is equipped with a voltage sensor 76 for detecting the output voltage of the battery 8 and a current sensor 78 for detecting the output current of the battery 8. These voltage sensor 76 and current sensor 78 output electrical signals corresponding to their respective detected values ​​to the BCM (Battery Control Module) 80. The BCM 80 is a controller that mainly controls the charging and discharging of the battery 8 and consists of a computer equipped with one or more processors (typically CPUs), a memory unit (ROM, RAM, etc.) for storing various programs, etc.

[0025] The BCM80 estimates the State of Charge (SOC) of the battery 8 from the voltage and current values ​​input from the voltage sensor 76 and the current sensor 78, and outputs it to the PCM84. Based on the SOC input from the BCM80 and the accelerator opening input from the accelerator opening sensor 82, which detects the opening of the accelerator pedal (not shown) of the series hybrid vehicle 1, the PCM84 calculates the rotational speed (required engine speed) and load (required engine load) of the rotary engine 14 required to obtain the desired engine output, and outputs them to the ECM70.

[0026] Furthermore, when starting the rotary engine 14, the PCM 84 calculates the rotational speed (required rotational speed) and the rate at which the rotational speed increases (rotational speed increase rate) when the starter generator 10 rotates the eccentric shaft 22 of the rotary engine 14, based on the water temperature of the rotary engine 14 input from the ECM 70, and outputs these to the SGCM (Starter Generator Control Module) 86. The SGCM 86 is a controller that mainly controls the starter generator 10 and consists of a computer equipped with one or more processors (typically CPUs), a memory unit for storing various programs (ROM, RAM, etc.), etc. Note that the SGCM 86 corresponds to an example of a "controller" in this invention.

[0027] Based on the requested engine speed and engine load input from the PCM84, the ECM70 calculates the control amounts for each device of the rotary engine 14, such as the metering oil pump 56, injectors 54, spark plugs 26, EGR valve 50, and throttle valve 36, and outputs electrical signals corresponding to the calculated control amounts to those devices. Furthermore, when starting the rotary engine 14, the SGCM86 calculates the control amount for the starter generator 10 based on the requested engine speed and rotation rate input from the PCM84, and outputs electrical signals corresponding to the calculated control amounts to the starter generator 10.

[0028] <Engine control processing> Next, the flow of the engine control process according to this embodiment will be described with reference to Figure 4. Figure 4 is a flowchart of the engine control process according to this embodiment.

[0029] The engine control process shown in Figure 4 is repeatedly executed at predetermined intervals by the PCM84, ECM70, and SGCM86 when the rotary engine 14 is stopped.

[0030] First, in step S101, the PCM84 acquires various information regarding the state of the series hybrid vehicle 1 from the ECM70, BCM80, accelerator position sensor 82, etc. Specifically, for example, the PCM84 acquires the SOC input from the BCM80, the accelerator position input from the accelerator position sensor 82, the water temperature of the rotary engine 14 input from the ECM70, as well as the vehicle speed, motor rotation speed, etc. Thereafter, while the engine control process is being executed, the PCM84 continues to acquire this information.

[0031] Next, in step S102, the PCM84 calculates the torque to be output by the electric motor 6 (required motor torque) based on the information acquired in step S101. Specifically, the PCM84 refers to a map or calculation formula (pre-set and stored) that defines the relationship between the accelerator opening and the required motor torque, and calculates the required motor torque corresponding to the accelerator opening acquired in step S101.

[0032] Next, in step S103, the PCM84 determines whether the SOC obtained in step S101 is below a predetermined threshold (for example, the lower limit of the allowable SOC, which is set and stored in advance). If the result is that the SOC is not below the threshold (step S103: No), that is, the SOC is greater than the threshold and there is no need to start the rotary engine 14 in order to charge the battery 8 with the starter generator 10, the process proceeds to step S104.

[0033] In step S104, the PCM84 determines whether the requested motor torque calculated in step S102 is greater than the torque that the electric motor 6 can output (outputtable motor torque). Outputtable motor torque is the torque that the electric motor 6 can output using only the power supplied from, for example, the battery 8, and maps and calculation formulas that define the relationship between SOC, motor speed, and outputtable motor torque are pre-set and stored. The PCM84 refers to these maps and calculation formulas, obtains the outputtable motor torque corresponding to the SOC and motor speed obtained in step S101, and compares it with the requested motor torque.

[0034] If, as a result of the determination in step S104, the requested motor torque is not greater than the outputtable motor torque (step S104: No), that is, the requested motor torque is less than or equal to the outputtable motor torque, and there is no need to start the rotary engine 14 in order to supply power from the starter generator 10 to the electric motor 6, then the PCM 84 terminates the engine control process without starting the rotary engine 14.

[0035] On the other hand, if the determination in step S103 indicates that the SOC is below a threshold (step S103: Yes), meaning that the rotary engine 14 needs to be started in order to charge the battery 8 with the starter generator 10, or if the determination in step S104 indicates that the requested motor torque is greater than the outputtable motor torque (step S104: Yes), meaning that the rotary engine 14 needs to be started in order to supply power from the starter generator 10 to the electric motor 6, the process proceeds to step S105, where the PCM 84, ECM 70, and SGCM 86 execute engine start control to start the rotary engine 14. Details of this engine start control will be described later.

[0036] After the rotary engine 14 is started by the engine start control in step S105, in step S106, the PCM84 and ECM70 perform combustion control to operate the rotary engine 14 at the required output. Details of this combustion control will be described later.

[0037] Next, in step S107, the PCM84 determines whether the SOC obtained from the BCM80 immediately beforehand is equal to or greater than the target value (for example, the allowable upper limit of the SOC, which is set in advance and stored). If the result is that the SOC is not equal to or greater than the target value (step S107: No), that is, if the SOC is less than the target value and it is necessary to continue charging the battery 8 by the starter generator 10, the process returns to step S106 and continues combustion control of the rotary engine 14.

[0038] On the other hand, if the result of the determination in step S107 is that the SOC is equal to or greater than the target value (step S107: Yes), that is, if it is not necessary to charge the battery 8 with the starter generator 10, the process proceeds to step S108.

[0039] In step S108, the PCM84 determines whether the requested motor torque is less than or equal to the outputtable motor torque. If the result is that the requested motor torque is not less than or equal to the outputtable motor torque (step S108: No), that is, if the requested motor torque is greater than the outputtable motor torque and it is necessary to continue supplying power from the starter generator 10 to the electric motor 6, the process returns to step S106 and continues combustion control of the rotary engine 14.

[0040] On the other hand, if the result of the determination in step S108 is that the requested motor torque is less than or equal to the outputtable motor torque (step S108: Yes), that is, if it is not necessary to supply power from the starter generator 10 to the electric motor 6, the process proceeds to step S109, where the PCM 84 stops the rotary engine 14 and terminates the engine control process.

[0041] <Engine start control process> Next, the flow of engine start control according to this embodiment will be explained with reference to Figures 5 to 8. Figure 5 is a flowchart of the engine start control process according to this embodiment, Figure 6 is a map showing the relationship between water temperature and the required rotational speed in engine start control, Figure 7 is a map showing the relationship between water temperature and the rate of rotational speed increase in engine start control, and Figure 8 is a map showing the relationship between water temperature and the amount of oil introduced at startup in engine start control.

[0042] As shown in Figure 5, when engine start control is initiated, in step S201, the PCM84 first sets the required rotational speed (required rotational speed) for when the starter generator 10 rotates the eccentric shaft 22 of the rotary engine 14 and ignition by the spark plug 26 is initiated, based on the water temperature of the rotary engine 14 acquired in step S101 of the engine control process, and outputs this to the SGCM86. Specifically, the PCM84 refers to a map (pre-set and stored) that defines the relationship between water temperature and the required rotational speed, such as shown in Figure 6, and sets the required rotational speed corresponding to the water temperature acquired in step S101. In the map illustrated in Figure 6, the horizontal axis represents water temperature and the vertical axis represents the required rotational speed. According to this map in Figure 6, if the water temperature is less than Tr(°C), the required rotational speed is set to Rr1(rpm), and if the water temperature is Tr(°C) or higher, the required rotational speed is set to Rr2(rpm), which is greater than Rr1. The water temperature Tr and the required rotational speeds Rr1 and Rr2 can be, for example, Tr=-5℃, Rr1=1200rpm, and Rr2=2000rpm, but other appropriate values ​​can be set depending on the rotary engine 14.

[0043] Thus, when the water temperature is relatively low at engine startup, that is, when the clearance between the rotor housing 16 and the rotor 20 is large and it is difficult to introduce oil during a cold start, setting the required rotational speed lower than when the water temperature is relatively high weakens the airflow in the working chamber 24 until ignition of the rotary engine 14 begins. This prevents the introduced oil from being blown away by the airflow before ignition of the rotary engine 14 begins.

[0044] Next, in step S202, based on the water temperature of the rotary engine 14 acquired in step S101 of the engine control process, the PCM 84 sets the rate of increase in the rotational speed (rotation increase rate) when rotating the eccentric shaft 22 of the rotary engine 14 by the starter generator 10, and outputs it to the SGCM 86. Specifically, the PCM 84 refers to a map (preset and stored in advance) defining the relationship between the water temperature and the rotation increase rate as shown in FIG. 7, for example, and sets the rotation increase rate corresponding to the water temperature acquired in step S101. In the map illustrated in FIG. 7, the horizontal axis represents the water temperature, and the vertical axis represents the rotation increase rate. According to this map of FIG. 7, when the water temperature is less than Ti1 (°C), the rotation increase rate is set to Ir1 (rpm / s), when the water temperature is Ti1 (°C) or more and less than Ti2 (°C), the rotation increase rate is set to Ir2 (rpm / s), when the water temperature is Ti2 (°C) or more and less than Ti3 (°C), the rotation increase rate is set to Ir3 (rpm / s), when the water temperature is Ti3 (°C) or more and less than Ti4 (°C), the rotation increase rate is set to Ir4 (rpm / s), and when the water temperature is Ti4 (°C) or more, the rotation increase rate is set to Ir5 (rpm / s). Here, the magnitude relationship of the rotation increase rates is Ir1 < Ir2 < Ir3 < Ir4 < Ir5. The water temperature and the rotation increase rate can be, for example, water temperature Ti1 = -5°C, Ti2 = 5°C, Ti3 = 15°C, Ti4 = 25°C, and rotation increase rates Ir1 = 1500 rpm / s, Ir2 = 2100 rpm / s, Ir3 = 2600 rpm / s, Ir4 = 3200 rpm / s, Ir5 = 3600 rpm / s, but other appropriate values can be set according to the rotary engine 14.

[0045] Thus, when the water temperature at engine startup is relatively low, that is, at cold startup when the clearance between the rotor housing 16 and the rotor 20 is large and it is difficult to interpose oil, by setting the rotation increase rate lower compared to when the water temperature is relatively high, the rate of increase in the strength of the air flow in the working chamber 24 becomes gentle, so that it is possible to prevent the oil introduced into the rotor housing 16 from being blown away by the air flow before sufficiently spreading between the rotor housing 16 and the rotor 20.

[0046] Next, in step S203, the ECM 70 sets the amount of oil to be introduced into the rotor housing 16 by the metering oil pump 56 when the rotary engine 14 is started (starting oil introduction amount) based on the water temperature of the rotary engine 14 obtained in step S101 of the engine control process. Specifically, the ECM 70 refers to a map (pre-set and stored) that defines the relationship between water temperature and starting oil introduction amount, such as shown in Figure 8, and sets the starting oil introduction amount corresponding to the water temperature obtained in step S101. In the map illustrated in Figure 8, the horizontal axis represents water temperature and the vertical axis represents starting oil introduction amount. According to this map in Figure 8, the higher the water temperature, the lower the starting oil introduction amount (l / min).

[0047] Thus, when the water temperature is relatively low at engine startup, that is, when the clearance between the rotor housing 16 and the rotor 20 is large and it is difficult for oil to intervene, during cold starts, setting a larger amount of oil to be introduced at startup compared to when the water temperature is relatively high ensures that the oil is reliably distributed between the rotor housing 16 and the rotor 20.

[0048] Next, in step S204, the ECM70 and SGCM86 start the rotary engine 14. Specifically, the SGCM86 drives the starter generator 10 according to the requested rotational speed and rotational speed increase rate input from the PCM84 in steps S201 and S202, and rotates the eccentric shaft 22 of the rotary engine 14. The ECM70 also introduces the amount of oil set in step S203 into the rotor housing 16 using the metering oil pump 56, and when the rotational speed of the eccentric shaft 22 reaches the requested rotational speed, it starts fuel injection by the injector 54 and ignition by the spark plug 26. After starting the rotary engine 14 in step S204, the PCM84 ends the engine start control and returns to the engine control shown in Figure 4.

[0049] <Combustion control treatment> Next, the combustion control flow of the rotary engine according to this embodiment will be explained with reference to Figures 9 to 17. Figure 9 is a flowchart of the combustion control process according to this embodiment, Figure 10 is a chart illustrating patterns of fuel injection timing according to engine speed in combustion control, Figure 11 is a table showing the relationship between engine speed and number of fuel injections in combustion control, Figure 12 is a map showing the relationship between engine speed and fuel injection end time in combustion control, Figure 13 is a map showing the relationship between engine load and fuel injection amount division ratio in combustion control, Figure 14 is a graph showing the relationship between eccentric shaft angle and heat generation rate in a rotary engine, Figure 15 is a graph showing the relationship between EGR rate and second-stage combustion ratio in a rotary engine, Figure 16 is a map showing the relationship between engine load and EGR rate in combustion control, and Figure 17 is a map showing the relationship between engine speed and EGR rate in combustion control.

[0050] As shown in Figure 9, when combustion control is started, in step S301, the PCM 84 first calculates the output of the rotor housing 16 (requested engine output) necessary to generate the desired power in the starter generator 10, based on the SOC input from the BCM 80 and the accelerator opening input from the accelerator opening sensor 82. Specifically, the PCM 84 refers to a map (pre-set and stored) that defines the relationship between SOC, accelerator opening, vehicle speed and the requested engine output, and calculates the requested engine output corresponding to the SOC, accelerator opening and vehicle speed acquired immediately before. In the above map, for example, the requested engine output is set to increase as the vehicle speed increases or as the accelerator opening increases.

[0051] Next, in step S302, the PCM84 calculates the rotational speed (requested engine speed) and load (requested engine load) of the rotary engine 14 necessary to obtain the requested engine output calculated in step S301, and outputs them to the ECM70. Specifically, the PCM84 refers to a map (pre-set and stored) that defines the relationship between the requested engine output, the requested engine speed, and the requested engine load, and calculates the requested engine speed and requested engine load corresponding to the requested engine output calculated in step S301. In the above map, for example, the requested engine load is set to be almost constant, and the requested engine speed increases as the requested engine output increases.

[0052] Next, in step S303, the ECM 70 sets the number of times fuel is injected into the injector 54 in one combustion cycle (fuel injection count), the timing of fuel injection (injection timing), and the amount of fuel to be injected (injection amount) for each working chamber 24 in order to operate the rotary engine 14 at the requested engine speed and requested engine load input from the PCM 84.

[0053] Figure 10 illustrates the fuel injection timing patterns set by the ECM 70 according to the engine speed detected by the eccentric shaft angle sensor 58. In Figure 10, the horizontal axis represents the injection timing expressed by the eccentric shaft angle (EA). The upper section shows the case when the engine speed R is greater than the first rotational speed R1, the middle section shows the case when the engine speed R is less than or equal to the first rotational speed R1 and greater than the second rotational speed R2, and the lower section shows the case when the engine speed R is less than or equal to the second rotational speed R2. As illustrated in Figure 10, the ECM 70 controls the injector 54 such that the number of fuel injections in each combustion cycle of the working chamber 24 increases and the timing of the end of the final fuel injection is retarded as the engine speed R becomes relatively lower.

[0054] Specifically, the ECM70 refers to a table (pre-set and stored in advance) that defines the relationship between the engine speed and the number of fuel injections, as shown in FIG. 11 for example, and sets the number of fuel injections corresponding to the engine speed detected by the eccentric shaft angle sensor 58. In the table shown in FIG. 11, when the engine speed R is higher than the first speed R1 (for example, 4000 rpm) (R1 < R), the number of fuel injections is set to one. Also, when the engine speed R is less than or equal to the first speed R1 and higher than the second speed R2 (for example, 3000 rpm) (R2 < R ≦ R1), the number of fuel injections is set to two. Further, when the engine speed R is less than or equal to the second speed R2 (R ≦ R2), the number of fuel injections is set to three. That is, when the engine speed R is less than or equal to the first speed R1, the ECM70 increases the number of fuel injections in each combustion cycle of the working chamber 24 compared to when the engine speed R is higher than the first speed R1. Also, when the engine speed R is less than or equal to the second speed R2 which is lower than the first speed R1, the ECM70 increases the number of fuel injections in each combustion cycle of the working chamber 24 compared to when the engine speed R is higher than the second speed R2, and sets the number of fuel injections.

[0055] Thus, the lower the engine speed R is, that is, the weaker the air flow in the working chamber 24 is, the more the number of fuel injections in each combustion cycle of the working chamber 24 is increased. By doing so, even if the air flow in the working chamber 24 is weak, the fuel can be evenly distributed from the leading side to the trailing side, and a homogeneous air-fuel mixture can be obtained.

[0056] Also, the ECM70 refers to a map (pre-set and stored in advance) that defines the relationship between the engine speed and the fuel injection end time, as shown in FIG. 12 for example, and sets the fuel injection end time corresponding to the engine speed detected by the eccentric shaft angle sensor 58. In the map shown in FIG. 12, the horizontal axis represents the engine speed and the vertical axis represents the fuel injection end time. The end time of the first fuel injection is represented by a solid line, the end time of the second fuel injection is represented by a dashed line, and the end time of the third fuel injection is represented by a dotted line.

[0057] As described above, when the engine speed R is higher than the first rotational speed R1, the number of fuel injections is set to 1, so the end time of the first injection becomes the end time of the last fuel injection in one combustion cycle. Also, when the engine speed R is less than or equal to the first rotational speed R1 and higher than the second rotational speed R2, the number of fuel injections is set to 2, so the end time of the second injection becomes the end time of the last fuel injection in one combustion cycle. Also, when the engine speed R is less than or equal to the second rotational speed R2, the number of fuel injections is set to 3, so the end time of the third injection becomes the end time of the last fuel injection in one combustion cycle. In the map shown in Figure 12, when the engine speed R is less than or equal to the first rotational speed R1 (when the number of fuel injections is 2 or 3), the end time of the last fuel injection (the end time of the second or third fuel injection) is retarded compared to when the engine speed R is higher than the first rotational speed R1 (when the number of fuel injections is 1). Furthermore, when the engine speed R is less than or equal to the second engine speed R2 (when there are 3 fuel injections), the timing of the end of the final fuel injection (the timing of the end of the 3rd fuel injection) is retarded compared to when the engine speed R is higher than the second engine speed R2 (when there are 2 fuel injections). In other words, the ECM70 sets the fuel injection amount so that when the engine speed R is less than or equal to the first engine speed R1, the timing of the end of the final fuel injection in each combustion cycle of the working chamber 24 is retarded compared to when the engine speed R is higher than the first engine speed R1, and when the engine speed R is less than or equal to the second engine speed R2 (lower than the first engine speed R1), the timing of the end of the final fuel injection in each combustion cycle of the working chamber 24 is retarded compared to when the engine speed R is higher than the second engine speed R2.

[0058] Thus, the lower the engine speed R is, that is, the weaker the airflow in the working chamber 24, the more the timing of the final fuel injection in each combustion cycle of the working chamber 24 is retarded. This allows the fuel to be distributed evenly from the leading side to the trailing side even when the airflow in the working chamber 24 is weak, thereby obtaining a homogeneous fuel-air mixture.

[0059] Furthermore, the ECM 70 refers to a map (pre-set and stored) that defines the relationship between the fuel injection amount per combustion cycle of each working chamber 24 (total fuel injection amount) and the engine load (charging efficiency), and obtains the total fuel injection amount corresponding to the requested engine load input from the PCM 84 in step S302. In addition, the ECM 70 refers to a map (pre-set and stored) that defines the relationship between the engine load (charging efficiency) and the division ratio of the fuel injection amount, such as shown in Figure 13, and obtains the division ratio corresponding to the requested engine load. Then, by dividing the total fuel injection amount according to the obtained division ratio, the fuel injection amount for each injection is set. Figure 13 is a map that defines the division ratio of the fuel injection amount when the engine speed R is less than or equal to the second speed R2 (when the number of fuel injections is 3), with the horizontal axis representing the engine load and the vertical axis representing the division ratio of the fuel injection amount. In Figure 13, the division ratio of the first fuel injection is represented by a solid line, the division ratio of the second fuel injection by a dashed line, and the division ratio of the third fuel injection by a dotted line. In the map shown in Figure 13, the division ratio is set such that the proportion of the first fuel injection increases and the proportions of the second and third injections decrease as the engine load increases. Although not shown, in the map that defines the division ratio of the fuel injection amount when the engine speed R is higher than the second R2 and less than or equal to the first R1 (when there are two fuel injections), the division ratio is set such that the proportion of the first fuel injection increases and the proportion of the second injection decreases as the engine load increases. In other words, when the engine speed R is less than or equal to the first R1, the ECM 70 sets the fuel injection amount such that the proportion of the first fuel injection amount in each combustion cycle of the working chamber 24 increases as the engine load increases at the same engine speed.

[0060] At the same rotational speed, the higher the engine load, the greater the amount of fresh air flowing into the working chamber 24 and the stronger the airflow toward the leading side. Therefore, by increasing the proportion of the first fuel injection amount and injecting more fuel toward the leading side, the mixing of the fresh air flowing toward the leading side and the fuel is promoted, and a homogeneous mixture can be obtained.

[0061] Next, in step S304, the ECM 70 sets the opening degree of the EGR valve 50 based on the engine speed detected by the eccentric shaft angle sensor 58 and the requested engine load input from the PCM 84.

[0062] In the rotary engine 14, due to the rotation of the rotor 20, a squish flow exists within the working chamber 24 during the combustion stroke, flowing from the trailing side (rear side in the direction of rotor rotation) to the leading side (front side in the direction of rotor rotation). Because of this squish flow, the flame generated by the ignition of the spark plug 26 propagates more easily to the leading side than the spark plug 26, but less easily to the trailing side. Therefore, the air-fuel mixture present on the trailing side of the spark plug 26 at the time of ignition does not begin to burn until it moves to the leading side as the rotor 20 rotates, resulting in a two-stage heat generation during the combustion stroke. Specifically, as illustrated in the graph of Figure 14, in the combustion stroke of the rotary engine 14, first, primary combustion (i) occurs due to the combustion of the air-fuel mixture in the range from the vicinity of the spark plug 26 to the leading end of the working chamber 24, and then, secondary combustion (ii) occurs due to the combustion of the air-fuel mixture located on the trailing side of the spark plug 26 in the working chamber 24.

[0063] As a result of their research, the inventors have found that when exhaust gas is introduced into the intake air by an EGR device in a rotary engine, the proportion of second-stage combustion in the heat generation during the combustion stroke changes depending on the EGR rate. The graph in Figure 15 shows the relationship between the EGR rate and the proportion of second-stage combustion in the heat generation during the combustion stroke. As shown in Figure 15, when exhaust gas is introduced into the intake air by an EGR device in a rotary engine, the higher the EGR rate, the greater the proportion of second-stage combustion in the heat generation during the combustion stroke. In the combustion control of this embodiment, by utilizing this relationship between the EGR rate and the proportion of second-stage combustion and setting the EGR rate according to the engine speed and engine load, both reduction of cooling loss and reduction of exhaust loss of the rotary engine 14 are achieved.

[0064] Specifically, the ECM84 refers to a map (pre-set and stored) that defines the relationship between engine load (charging efficiency) and EGR rate, such as the one shown in Figure 16, and obtains the EGR rate corresponding to the requested engine load input from the PCM84 in step S302. The map in Figure 16 illustrates the relationship between engine load and EGR rate when the engine speed R is the same, with the horizontal axis representing engine load and the vertical axis representing the EGR rate. According to this map in Figure 16, the higher the engine load, the higher the EGR rate and the smaller the rate of increase in the EGR rate.

[0065] When the engine load is relatively high, the pressure rise due to the main combustion occurring on the leading side of the working chamber 24 becomes steeper, and cooling losses tend to increase relatively. Therefore, as described above, when the engine load is relatively high, the EGR rate is set higher than when the engine load is relatively low, and the proportion of second-stage combustion is increased, thereby easing the pressure rise due to the main combustion and reducing cooling losses. In addition, as the engine load increases, the rate of increase in the EGR rate in response to the increase in engine load is reduced, which prevents exhaust losses caused by the late-timing second-stage combustion from becoming excessive.

[0066] Furthermore, when the engine load is relatively low, the cooling loss due to primary combustion is small, so the effect of exhaust loss due to the delayed occurrence of secondary combustion after primary combustion becomes relatively larger. Therefore, when the engine load is relatively low, the exhaust gas recirculation rate can be set lower than when the engine load is relatively high, thereby reducing the proportion of secondary combustion and thus reducing exhaust loss caused by secondary combustion.

[0067] Furthermore, the ECM84 refers to a map (pre-set and stored) that defines the relationship between engine speed and EGR rate, such as the one shown in Figure 17, and obtains the EGR rate corresponding to the engine speed detected by the eccentric shaft angle sensor 58. The map in Figure 17 illustrates the relationship between engine speed and EGR rate when the engine load is the same, with the horizontal axis representing engine speed and the vertical axis representing the EGR rate. According to this map in Figure 17, the higher the engine speed, the lower the EGR rate and the smaller the rate of decrease in the EGR rate.

[0068] When the engine speed is relatively low, the squish flow from the trailing side to the leading side within the working chamber 24 during the combustion stroke is relatively weak, and flame propagation is slower. As a result, unburned fuel mixture accumulating on the trailing side of the working chamber 24 self-ignites faster than the main combustion flame can propagate, making knocking more likely. Therefore, when the engine speed is relatively low, setting the EGR rate higher than when the engine speed is relatively high increases the proportion of second-stage combustion, that is, decreases the proportion of main combustion. This slows down the pressure rise caused by main combustion and suppresses the occurrence of knocking. On the other hand, when the engine speed is relatively high and knocking is less likely to occur, setting the EGR rate lower reduces the proportion of second-stage combustion, thereby reducing exhaust losses caused by the later-timing second-stage combustion.

[0069] As described above, the ECM70 acquires the EGR rate corresponding to the engine speed and the required engine load, and sets the opening degree of the EGR valve 50 corresponding to the acquired EGR rate based on a map or calculation formula (which is pre-set and stored) that defines the relationship between the EGR rate and the opening degree of the EGR valve 50.

[0070] Next, in step S305, the ECM 70 sets the ignition timing for the spark plug 26 based on the engine speed detected by the eccentric shaft angle sensor 58 and the requested engine load input from the PCM 84. Specifically, the ECM 70 refers to a map (pre-set and stored) that defines the relationship between the ignition timing for the spark plug 26 and the engine speed and engine load (volumetric efficiency), and sets the ignition timing corresponding to the engine speed detected by the eccentric shaft angle sensor 58 and the requested engine load input from the PCM 84 in step S302.

[0071] Next, in step S306, the PCM 84 calculates the control amounts for various devices of the rotary engine 14, such as the injectors 54, spark plugs 26, EGR valves 50, and throttle valves 36, so that the number of fuel injections, fuel injection timing, and fuel injection amount set in step S303, the EGR valve opening degree set in step S304, and the ignition timing set in step S305 are achieved. The PCM 84 then outputs electrical signals corresponding to the calculated control amounts to these devices. This control of various devices continues until the rotary engine 14 is operated at the requested engine speed and engine load input from the PCM 84. After step S306, the PCM 84 terminates combustion control and returns to the engine control shown in Figure 4.

[0072] <Variation> While embodiments of the present invention have been described above, the specific configurations and means of the present invention can be arbitrarily modified and improved within the scope of the technical idea of ​​each invention described in the claims. Such modifications will be described below.

[0073] First, the problems that the invention aims to solve and the effects of the invention are not limited to those described above. The present invention may solve problems not described or produce effects not described, or it may solve only some of the problems described or produce only some of the effects described.

[0074] In the embodiments described above, the case in which the rotary engine 14 is mounted on a series hybrid vehicle 1 was explained as an example, but the combustion control of this embodiment can also be applied to rotary engines mounted on parallel hybrid vehicles, split hybrid vehicles, and non-hybrid vehicles.

[0075] <Mechanism and Effects> Next, the effects and advantages of the series hybrid vehicle 1 and engine system 12 of this embodiment will be described.

[0076] In this embodiment, the ECM 70 controls the EGR valve 50 such that, at the same engine speed, when the engine load is relatively high, the EGR rate of intake air introduced into the working chamber 24 is higher than when the engine load is relatively low. As a result, when the engine load is relatively high, the proportion of second-stage combustion is increased compared to when the engine load is relatively low, and the pressure rise due to main combustion is slowed down, thereby reducing cooling losses.

[0077] Furthermore, when the engine speed R is less than or equal to the first rotational speed R1, the ECM 70 controls the injector 54 so that the number of fuel injections in each combustion cycle of the working chamber 24 is greater and the timing of the final fuel injection is delayed compared to when the engine speed R is greater than the first rotational speed R1. As a result, when the engine speed R is relatively low, that is, when the airflow in the working chamber 24 is relatively weak, the number of fuel injections in each combustion cycle of the working chamber 24 is increased and the timing of the final fuel injection is delayed, so that even if the airflow in the working chamber 24 is weak, the fuel can be distributed evenly from the leading side to the trailing side to obtain a homogeneous mixture, and the ratio of main combustion to second-stage combustion according to the EGR rate can be adjusted more accurately.

[0078] Furthermore, the ECM70 controls the EGR valve 50 so that, at the same engine speed, the EGR rate increases as the engine load increases, while the rate of increase in the EGR rate decreases. As a result, the increase in the EGR rate is suppressed as the engine load increases, preventing excessive exhaust losses caused by the late-timing second-stage combustion.

[0079] In particular, in a series hybrid vehicle 1 in which the driving force of the rotary engine 14 is used solely to drive the starter generator 10, the rotary engine 14 tends to be operated in a region of high thermal efficiency, that is, a region of relatively high engine load. Therefore, the engine system 12 of this embodiment, which can reduce cooling losses when the engine load is relatively high, is suitable for the series hybrid vehicle 1. [Explanation of symbols]

[0080] 1 Series Hybrid Vehicles 2 Reducer 4 drive wheels 6 Electric motor 8 batteries 10 Starter Generator 12 Engine System 14 Rotary Engine 16 Rotor Housing 18 Side Housing 20 rotors 22 Eccentric Shaft 24 Working chamber 26 Spark plugs 28 intake ports 30 exhaust ports 32 Intake passage 34 Exhaust passage 36 Throttle valve 38 Throttle position sensor 40 Airflow Sensor 42 Air Cleaner 44 EGR device 46 EGR passage 48 EGR cooler 50 EGR valve 52 EGR valve opening sensor 54 Injectors 56 Metering Oil Pump 58 Eccentric shaft angle sensor 60 Intake pressure sensor 62 Intake air temperature sensor 64 Water temperature sensor 70 ECM 72 processors 74 Memory section 76 Voltage Sensor 78 Current Sensor 80 BCM 82. Accelerator position sensor 84 PCM 86 SGCM

Claims

1. A rotary engine comprising a rotor housing, a side housing, a rotor housed in a rotor housing chamber surrounded by the rotor housing and side housing, forming three working chambers, an intake passage for guiding air into the working chambers, and an injector for injecting fuel into one of the working chambers, An EGR passage that recirculates the exhaust gas of the rotary engine back into the intake passage, An EGR valve that adjusts the amount of exhaust gas recirculated into the intake passage, A controller configured to control the opening degree of the EGR valve, The rotary engine is equipped with a rotational speed sensor for detecting the engine speed of the rotary engine, The controller controls the EGR valve such that, at the same engine speed, when the load on the rotary engine is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the load on the rotary engine is relatively low. The controller is configured to control fuel injection by the injector, and when the engine speed is less than or equal to a first rotational speed, it controls the injector such that the number of fuel injections in each combustion cycle of the working chamber is greater than when the engine speed is higher than a first rotational speed, and the timing of the end of the final fuel injection is delayed. Engine system.

2. A rotary engine having a rotor housing, a side housing, a rotor housed in a rotor housing chamber surrounded by the rotor housing and the side housing, forming three working chambers, and an intake passage for guiding air to the working chambers, An EGR passage that recirculates the exhaust gas of the rotary engine back into the intake passage, An EGR valve that adjusts the amount of exhaust gas recirculated into the intake passage, The system includes a controller configured to control the opening degree of the EGR valve, The controller controls the EGR valve such that, at the same engine speed, when the load on the rotary engine is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the load on the rotary engine is relatively low. The controller controls the EGR valve such that, at the same engine speed, the higher the load on the rotary engine, the higher the EGR rate and the smaller the rate of increase in the EGR rate. Engine system.

3. A rotary engine having a rotor housing, a side housing, a rotor housed in a rotor housing chamber surrounded by the rotor housing and the side housing and forming three working chambers, an intake passage for introducing air into the working chambers, and an injector for injecting fuel into one of the working chambers, An EGR passage that recirculates the exhaust gas of the rotary engine back into the intake passage, An EGR valve that adjusts the amount of exhaust gas recirculated into the intake passage, A controller configured to control the opening degree of the EGR valve, The rotary engine is equipped with a rotational speed sensor for detecting the engine speed of the rotary engine, The controller controls the EGR valve such that, at the same engine speed, when the load on the rotary engine is relatively high, the EGR rate of intake air introduced into the working chamber is higher than when the load on the rotary engine is relatively low. The controller is configured to control fuel injection by the injector, and when the engine speed is less than or equal to the first rotational speed, it controls the injector such that the number of fuel injections in each combustion cycle of the working chamber is greater than when the engine speed is higher than the first rotational speed, and the timing of the end of the final fuel injection is delayed. The controller controls the EGR valve such that, at the same engine speed, the higher the load on the rotary engine, the higher the EGR rate and the smaller the rate of increase in the EGR rate. Engine system.

4. A series hybrid vehicle comprising an electric motor as a driving force source and a generator capable of supplying power to the electric motor, The engine system comprises the engine system described in claim 1 or 2, The rotary engine drives the generator, Series hybrid vehicle.

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