Hybrid vehicle

Abstract

A control device of a hybrid vehicle executes intake gas flow rate adjustment processing, drag processing, evaporated fuel adjustment processing, and start processing. The intake gas flow rate adjustment processing includes adjusting an opening degree of a throttle valve to an open state. The drag processing includes dragging an internal combustion engine by controlling a motor generator. The evaporated fuel adjustment processing includes allowing evaporated fuel to flow in an evaporated fuel passage by adjusting an opening degree of an evaporated fuel adjustment valve in the drag processing. The start processing includes starting the internal combustion engine by controlling an ignition device to perform ignition in the drag processing.

Description

Technical Field

[0001] This disclosure relates to hybrid vehicles. Background Technology

[0002] Japanese Patent Application Publication No. 2003-343365 discloses a fuel supply device for an internal combustion engine. The fuel supply device includes a fuel tank for storing fuel, an evaporation fuel passage for directing vaporized fuel generated in the fuel tank along with air to the combustion chamber of the internal combustion engine, and a booster pump installed in the evaporation fuel passage. Furthermore, the fuel supply device includes a control device for controlling the booster pump. This control device drives the booster pump to direct the vaporized fuel generated in the fuel tank toward the combustion chamber when the internal combustion engine is started.

[0003] In the aforementioned fuel supply system, a booster pump is required to supply evaporative fuel to the combustion chamber. This increases the cost of using a booster pump. Furthermore, sufficient space must be allocated to house the booster pump. Therefore, there is a need for a technology that supplies evaporative fuel to the combustion chamber without requiring a booster pump when starting the internal combustion engine. Summary of the Invention

[0004] This disclosure provides a hybrid vehicle. The hybrid vehicle has an internal combustion engine as a drive source. The internal combustion engine has: an engine body having a combustion chamber; a fuel injection device configured to supply liquid fuel to the combustion chamber; an ignition device configured to ignite for combustion in the combustion chamber; an intake passage connected to the combustion chamber and configured to allow intake gas to flow into the combustion chamber; and a throttle valve disposed in the intake passage and configured to adjust the flow rate of the intake gas, i.e., the intake gas flow rate. The hybrid vehicle further comprises: an evaporative fuel passage, connecting from the fuel tank to the portion between the throttle valve and the combustion chamber in the intake passage, configured to allow evaporative fuel generated in the fuel tank to flow together with air into the intake passage; an evaporative fuel regulating valve, disposed in the evaporative fuel passage, configured to adjust the opening degree of the evaporative fuel passage; an electric generator, capable of driving the crankshaft of the internal combustion engine to rotate without injecting the liquid fuel from the fuel injection device; and a control device configured to control the starting of the internal combustion engine by controlling the ignition device, the throttle valve, the evaporative fuel regulating valve, and the electric generator. The control device is configured to perform: an intake air flow rate adjustment process, controlling the opening degree of the throttle valve to be open; a driving process, driving the internal combustion engine by controlling the electric generator; an evaporative fuel regulation process, allowing the evaporative fuel to flow in the evaporative fuel passage by adjusting the opening degree of the evaporative fuel regulating valve during the driving process; and a starting process, starting the internal combustion engine by controlling the ignition device to ignite during the driving process.

[0005] Based on the above configuration, the negative pressure generated by the motor drive allows evaporative fuel to be supplied to the combustion chamber. Furthermore, by adjusting the evaporative fuel supply, the amount of evaporative fuel supplied to the combustion chamber can be controlled to a level suitable for starting the internal combustion engine. Therefore, in starting the internal combustion engine by burning the evaporative fuel, a device such as a booster pump, which is only used to supply evaporative fuel, is not required. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of a hybrid vehicle.

[0007] Figure 2 yes Figure 1 A schematic diagram of a hybrid vehicle.

[0008] Figure 3 This is a flowchart illustrating a portion of a series of processes in the internal combustion engine starting procedure, including the first starting process.

[0009] Figure 4 This is a flowchart illustrating a portion of a series of processes in the internal combustion engine starting procedure, including the second starting process.

[0010] Figure 5 This is a flowchart illustrating a part of the internal combustion engine start-up procedure that includes the process when the maximum supply amount is insufficient.

[0011] Figure 6 This is a flowchart illustrating a part of the internal combustion engine starting procedure that includes the process when the intake negative pressure does not reach the required negative pressure. Detailed Implementation

[0012] (One implementation method)

[0013] Hereinafter, one embodiment of the hybrid vehicle will be described with reference to the accompanying drawings.

[0014] <Brief Components of a Hybrid Vehicle>

[0015] First, the general structure of the hybrid vehicle 100 will be explained.

[0016] like Figure 1 As shown, the hybrid vehicle 100 has a spark-ignition internal combustion engine 10 as its drive source. In addition, the hybrid vehicle 100 has a first electric generator 71 and a second electric generator 72 that function as both an electric motor and a generator. Therefore, the hybrid vehicle 100 is a so-called hybrid vehicle.

[0017] The internal combustion engine 10 has an internal combustion engine body 11. The internal combustion engine body 11 has multiple cylinders 12 and a crankshaft 13.

[0018] Cylinder 12 is the space used to burn the mixture of fuel and intake air. The main body of the internal combustion engine 11 has 4 cylinders 12.

[0019] The crankshaft 13 is connected to pistons (not shown) located within each cylinder 12. The space defined by the inner wall of the cylinder 12 and the piston area is the combustion chamber R. When fuel burns in each combustion chamber R, the piston located within that cylinder 12 actuates. As a result, the crankshaft 13 connected to the piston rotates.

[0020] In addition, the internal combustion engine 10 includes an intake passage 21, a throttle valve 22, multiple fuel injection devices 23, and multiple ignition devices 24. Furthermore, the internal combustion engine 10 includes an exhaust passage 26, a catalyst 27, and a filter 28.

[0021] The intake passage 21 is connected to the cylinder 12. A portion of the intake passage 21, including the downstream end, branches into four branches. Each branch is connected to a cylinder 12. The intake passage 21 is used to allow intake gas to flow from the outside of the internal combustion engine 10 to the combustion chamber R.

[0022] Throttle valve 22 is located in the intake passage 21, upstream relative to the branch section. Throttle valve 22 adjusts the amount of intake gas flowing in the intake passage 21, i.e., the intake gas flow rate.

[0023] Fuel injection device 23 is located near the downstream end of intake passage 21. The internal combustion engine 10 has four fuel injection devices 23 corresponding to its four cylinders 12. The fuel injection devices 23 inject liquid fuel supplied from the fuel tank 31 (described later) into the intake passage 21. That is, the fuel injection devices 23 supply fuel to the combustion chamber R via the intake passage 21. Ignition device 24 is located in cylinder 12. The internal combustion engine 10 has four ignition devices 24 corresponding to its four cylinders 12. The ignition devices 24 ignite the fuel-intake mixture in the combustion chamber R using spark discharge.

[0024] Exhaust passage 26 is connected to cylinder 12. A portion of exhaust passage 26, including the upstream end, branches into four branches. Each branch is connected to a cylinder 12. Exhaust passage 26 discharges exhaust gases from each cylinder 12 to the outside of the internal combustion engine 10.

[0025] Catalyst 27 is located downstream of the branch section in exhaust passage 26. Catalyst 27 purifies the exhaust gases flowing in exhaust passage 26. Filter 28 is located downstream of catalyst 27 in exhaust passage 26. Filter 28 traps particulate matter contained in the exhaust gases flowing in exhaust passage 26.

[0026] like Figure 2As shown, the hybrid vehicle 100 includes a fuel supply mechanism 30. The fuel supply mechanism 30 includes a fuel tank 31, an evaporative fuel passage 32, a shut-off valve 33, and an evaporative fuel regulating valve 34.

[0027] Fuel tank 31 is a tank that stores fuel that burns in combustion chamber R. Evaporated fuel passage 32 is a passage for allowing the evaporated fuel generated in fuel tank 31 to flow with air to intake passage 21. Evaporated fuel passage 32 connects from fuel tank 31 to a portion of intake passage 21 that is downstream of throttle valve 22 and upstream of combustion chamber R.

[0028] A shut-off valve 33 is installed midway through the evaporative fuel passage 32. The shut-off valve 33 switches the flow path of the evaporative fuel passage 32 to a fully open or fully closed state. An evaporative fuel regulating valve 34 is installed downstream of the shut-off valve 33 in the evaporative fuel passage 32. The evaporative fuel regulating valve 34 adjusts the opening degree of the flow path in the evaporative fuel passage 32. The opening degree of the evaporative fuel regulating valve 34 can be continuously changed between a fully open state and a fully closed state. Furthermore, "open state" is not limited to a fully open state; it includes all opening degrees to which evaporative fuel can flow in the evaporative fuel passage 32. In other words, "open state" refers to any opening degree other than a fully closed state.

[0029] The fuel supply mechanism 30 is equipped with a supply pump 35 and a liquid fuel passage 36.

[0030] The supply pump 35 is an electrically powered pump that draws liquid fuel stored in the fuel tank 31. The liquid fuel passage 36 is connected from the supply pump 35 to the fuel injection device 23. That is, the liquid fuel passage 36 is the passage through which the liquid fuel discharged from the supply pump 35 flows to the fuel injection device 23.

[0031] like Figure 1 As shown, the hybrid vehicle 100 includes a first planetary gear mechanism 40, a ring gear shaft 45, a second planetary gear mechanism 50, a reduction mechanism 62, a differential mechanism 63, and multiple drive wheels 64.

[0032] The first planetary gear mechanism 40 includes a sun gear 41, a ring gear 42, multiple pinions 43, and a planet carrier 44. The sun gear 41 is an external gear. The sun gear 41 is connected to the first electric generator 71. The ring gear 42 is an internal gear, coaxial with the sun gear 41. Each pinion 43 is located between the sun gear 41 and the ring gear 42. Each pinion 43 meshes with both the sun gear 41 and the ring gear 42. The planet carrier 44 supports the pinions 43. The pinions 43 are capable of rotation on their own axis and also revolve around a central axis by rotating together with the planet carrier 44. The planet carrier 44 is connected to the crankshaft 13.

[0033] The gear shaft 45 is connected to the gear ring 42. Furthermore, the gear shaft 45 is connected to the drive wheel 64 via a reduction mechanism 62 and a differential mechanism 63. The reduction mechanism 62 reduces the rotational speed of the gear shaft 45. The differential mechanism 63 allows a speed difference to be generated between the left and right drive wheels 64.

[0034] The second planetary gear mechanism 50 includes a sun gear 51, a ring gear 52, multiple pinions 53, a planet carrier 54, and a housing 55. The sun gear 51 is an external gear. The sun gear 51 is connected to the second electric generator 72. The ring gear 52 is an internal gear, coaxial with the sun gear 51. The ring gear 52 is connected to the ring gear shaft 45. Each pinion 53 is located between the sun gear 51 and the ring gear 52. Each pinion 53 meshes with both the sun gear 51 and the ring gear 52. The planet carrier 54 supports the pinions 53. The pinions 53 are capable of rotation. The planet carrier 54 is fixed to the housing 55. Therefore, the pinions 53 are in a state where they cannot revolve around the sun gear.

[0035] The hybrid vehicle 100 includes a battery 75, a first converter 76, and a second converter 77.

[0036] Battery 75 is a rechargeable battery. First converter 76 performs AC / DC power conversion between the first electric generator 71 and battery 75. Furthermore, first converter 76 adjusts the amount of power supplied and received between the first electric generator 71 and battery 75. Second converter 77 performs AC / DC power conversion between the second electric generator 72 and battery 75. Second converter 77 adjusts the amount of power supplied and received between the second electric generator 72 and battery 75. Moreover, the first electric generator 71 can rotate the crankshaft 13 of the internal combustion engine body 11 without injecting liquid fuel from the fuel injection device 23. In other words, the first electric generator 71 can drive the internal combustion engine 10.

[0037] The hybrid vehicle 100 is equipped with a catalyst temperature sensor 81, a coolant temperature sensor 82, an evaporative fuel concentration sensor 83, a negative pressure sensor 84, an accelerator operation quantity sensor 85, and a power switch 86.

[0038] The catalyst temperature sensor 81 is installed in the exhaust passage 26 on the downstream side relative to the catalyst 27. The catalyst temperature sensor 81 detects the temperature of the exhaust gas flowing out of the catalyst 27 as the catalyst temperature TC.

[0039] Coolant temperature sensor 82 detects the temperature of the cooling water used to cool the internal combustion engine body 11, i.e., the cooling water temperature TW. Although not shown in the figure, the cooling water temperature sensor 82 is installed at the outlet of the water jacket, which is defined inside the internal combustion engine body 11. The cooling water temperature sensor 82 detects the temperature of the cooling water flowing in this water jacket as the cooling water temperature TW.

[0040] The evaporative fuel concentration sensor 83 detects the evaporative fuel concentration CF, which represents the concentration of evaporative fuel in the gas filling the fuel tank 31. The evaporative fuel concentration sensor 83 is installed inside the fuel tank 31.

[0041] The negative pressure sensor 84 is installed in the intake passage 21 near the connection point with the evaporative fuel passage 32. The negative pressure sensor 84 detects the negative pressure at the connection point in the intake passage 21 with the evaporative fuel passage 32 as the intake negative pressure PI. The accelerator operation amount sensor 85 detects the amount of accelerator pedal operation by the driver, i.e., the accelerator operation amount ACC.

[0042] The power switch 86 issues a start request R1 by being turned on when the power supply to the hybrid vehicle 100 is in the off state. The power switch 86 issues a stop request R2 by being turned off when the power supply to the hybrid vehicle 100 is in the on state. The crankshaft angle sensor 87 is located near the crankshaft 13. The crankshaft angle sensor 87 detects the rotational phase SC of the crankshaft 13.

[0043] <Control Device>

[0044] The hybrid vehicle 100 includes a control device 90. The control device 90 controls the hybrid vehicle 100. Specifically, when executing the internal combustion engine starting procedure PS (described later), the control device 90 controls the throttle valve 22, fuel injection device 23, ignition device 24, shut-off valve 33, evaporative fuel regulating valve 34, and the first electric generator 71. The control device 90 obtains a signal indicating the catalyst temperature TC from the catalyst temperature sensor 81. The control device 90 obtains a signal indicating the coolant temperature TW from the coolant temperature sensor 82. The control device 90 obtains a signal indicating the evaporative fuel concentration CF from the evaporative fuel concentration sensor 83. The control device 90 obtains a signal indicating the intake negative pressure PI from the negative pressure sensor 84. The control device 90 obtains a signal indicating the accelerator operation amount ACC from the accelerator operation amount sensor 85. The control device 90 obtains signals indicating start request R1 and stop request R2 from the power switch 86. The control device 90 obtains a signal indicating the rotational phase SC of the crankshaft 13 from the crankshaft angle sensor 87.

[0045] The control device 90 includes a CPU 91, peripheral circuits 92, ROM 93, storage device 94, and bus 95. Bus 95 connects the CPU 91, peripheral circuits 92, ROM 93, and storage device 94 in a manner enabling communication between them. Peripheral circuits 92 include circuits for generating clock signals that define internal operations, power supply circuits, reset circuits, etc. ROM 93 pre-stores various programs for the CPU 91 to perform various controls. The CPU 91 controls the hybrid vehicle 100 by executing the various programs stored in ROM 93. In particular, ROM 93 stores an internal combustion engine starting program PS for starting the internal combustion engine 10. Furthermore, the CPU 91 controls the throttle valve 22, fuel injection device 23, ignition device 24, shut-off valve 33, evaporative fuel regulating valve 34, and first electric generator 71 by executing the internal combustion engine starting program PS, thereby starting the internal combustion engine 10. Furthermore, in Figure 2 The diagram shows the signals used by the CPU91 to control these devices as operation signals MS1 to MS6.

[0046]

[0047] <Handling procedures when the unit is cold>

[0048] When a request to start the internal combustion engine 10 occurs while the internal combustion engine 10 is stopped, the CPU 91 executes the internal combustion engine start-up procedure PS. For example, when the hybrid vehicle 100 is in a power-off state and the control device 90 receives a signal indicating a start-up request R1 from the power switch 86, the CPU 91 determines that a start-up request for the internal combustion engine 10 has occurred. Furthermore, when the hybrid vehicle 100 is in a power-off state, the shut-off valve 33 is fully closed.

[0049] like Figure 3 As shown, when the CPU 91 begins a series of processes in the internal combustion engine starting procedure PS, it first performs step S11. In step S11, the CPU 91 determines whether the catalyst temperature TC is lower than the cold engine catalyst temperature TCL. The cold engine catalyst temperature TCL is preset to be a value lower than the activation temperature of the catalyst 27. If the catalyst temperature TC is lower than the cold engine catalyst temperature TCL (S11: Yes), the CPU 91 proceeds the process to step S12.

[0050] In step S12, the CPU 91 determines whether the coolant temperature TW is lower than the cold engine coolant temperature TWL. The cold engine coolant temperature TWL is preset as a temperature used to determine whether the preheating of the internal combustion engine 10 is complete. The cold engine coolant temperature TWL is, for example, several tens of degrees. If the coolant temperature TW is lower than the cold engine coolant temperature TWL (S12: Yes), the CPU 91 proceeds to step S13. That is, in step S12, the CPU 91 performs a cold engine determination process to determine whether the internal combustion engine 10 is started in a cold engine state. Furthermore, if the coolant temperature TW is lower than the cold engine coolant temperature TWL, the CPU 91 determines that the internal combustion engine 10 is in a cold engine state where the temperature is below the preset predetermined temperature. On the other hand, if the coolant temperature TW is higher than the cold engine coolant temperature TWL, the CPU 91 determines that the internal combustion engine 10 is not in a cold engine state. In addition, the cold engine coolant temperature TWL is equivalent to the predetermined temperature.

[0051] In step S13, the CPU91 calculates, in this series of processes, the flow rate of gas flowing in the evaporative fuel passage 32, i.e., the first gas flow rate V1, and the flow rate of gas flowing in the intake passage 21, i.e., the second gas flow rate V2, required for the first start-up process described later. The first gas flow rate V1 is the flow rate of gas flowing in the evaporative fuel passage 32 per unit time required when the torque required for starting the internal combustion engine 10 is provided solely by evaporative fuel. That is, when the gas at the first gas flow rate V1 flows through the evaporative fuel passage 32, the mass of evaporative fuel supplied to the intake passage 21 per unit time is consistent with the mass of fuel per unit time required for starting the internal combustion engine 10, i.e., the required amount DA. Furthermore, the required amount DA is preset through experiments and simulations. In this step S13, the CPU91 calculates the first gas flow rate V1 based on the signal representing the evaporative fuel concentration CF from the evaporative fuel concentration sensor 83. Specifically, the higher the evaporative fuel concentration CF, the smaller the value that CPU91 will calculate for the first gas flow rate V1.

[0052] The second gas flow rate V2 is the flow rate of gas flowing in the intake passage 21 per unit time required to achieve the target air-fuel ratio for the gas supplied to the combustion chamber R when the flow rate of the gas flowing in the evaporative fuel passage 32 becomes the first gas flow rate V1. The target air-fuel ratio is, for example, the stoichiometric air-fuel ratio. Afterwards, the CPU 91 advances the process to step S14.

[0053] In step S14, the CPU91 determines whether, during the current start-up of the internal combustion engine 10, the required mass of fuel per unit time, i.e., the required amount DA, can be supplied solely through vaporized fuel. The maximum supply amount SAL is defined as the mass of vaporized fuel supplied to the intake passage 21 per unit time when the vaporized fuel regulating valve 34 is fully open. If the required amount DA is less than or equal to the maximum supply amount SAL, then it can be supplied solely through vaporized fuel.

[0054] Specifically, the CPU 91 determines the flow rate by comparing the first gas flow rate V1 calculated in step S13 with the maximum gas flow rate VL, which is the maximum gas flow rate that can flow in the evaporation fuel passage 32 per unit time. When the first gas flow rate V1 is less than or equal to the maximum gas flow rate VL, the CPU 91 determines that the required amount DA can be supplied solely by evaporation fuel. Furthermore, the maximum gas flow rate VL is the maximum gas flow rate that can flow in the evaporation fuel passage 32 per unit time when the evaporation fuel regulating valve 34 is fully open. And when the first gas flow rate V1 is less than or equal to the maximum gas flow rate VL (S14: Yes), the CPU 91 proceeds the process to step S15.

[0055] In step S15, CPU 91 performs intake gas flow rate adjustment processing. In this process, CPU 91 controls throttle valve 22, adjusting its opening to the open state. In step S15, CPU 91 adjusts the opening of throttle valve 22 such that the gas flow rate per unit time in the intake passage 21 becomes a second gas flow rate V2. That is, CPU 91 adjusts the opening of throttle valve 22 such that the mass of air supplied to combustion chamber R per unit time divided by the required amount DA becomes the target air-fuel ratio. Afterwards, CPU 91 proceeds to step S16.

[0056] In step S16, CPU 91 initiates the drive process. During this process, CPU 91 controls the first electric generator 71 to drive the internal combustion engine 10. Specifically, CPU 91 controls the first electric generator 71 via the first converter 76 to apply torque from the first electric generator 71 to the crankshaft 13. Then, CPU 91 uses the torque from the first electric generator 71 to rotate the crankshaft 13 at a predetermined speed. This generates a negative pressure in the combustion chamber R. CPU 91 continues this drive process after step S16. Afterward, CPU 91 advances the process to step S17.

[0057] In step S17, the CPU91 determines whether a predetermined time ST has elapsed since the start of the dragging process. The predetermined time ST is the time required from the start of the dragging process until the negative pressure in the combustion chamber R reaches the predetermined required negative pressure PN, and is set through testing and / or simulation. The required negative pressure PN is set to the pressure at which sufficient gas can be supplied from the evaporative fuel passage 32. If the predetermined time ST has not elapsed (S17), the CPU91 repeats the process of step S17. On the other hand, if the predetermined time ST has elapsed (S17), the CPU91 advances the process to step S18.

[0058] In step S18, CPU91 determines whether the intake negative pressure PI is smaller than the required negative pressure PN. If the intake negative pressure PI is smaller than the required negative pressure PN, CPU91 proceeds the process to step S19.

[0059] In step S19, CPU 91 performs an evaporative fuel adjustment process. In this process, CPU 91 allows evaporative fuel to flow in the evaporative fuel passage 32 by adjusting the opening of the evaporative fuel adjustment valve 34 during the drag process. CPU 91 adjusts the opening of the evaporative fuel adjustment valve 34 such that the mass of evaporative fuel supplied to the intake passage 21 per unit time is close to the required amount DA. Specifically, CPU 91 adjusts the opening of the evaporative fuel adjustment valve 34 such that the gas flow rate flowing in the evaporative fuel passage 32 per unit time becomes the first gas flow rate V1. Therefore, after executing step S19, the mass of evaporative fuel supplied to the intake passage 21 per unit time matches the required amount DA. Afterward, CPU 91 advances the process to step S20.

[0060] In step S20, CPU91 changes the closing valve 33 from a fully closed state to a fully open state. Then, CPU91 proceeds the process to step S21.

[0061] In step S21, CPU 91 performs a first start-up process. In the first start-up process, CPU 91 starts the internal combustion engine 10 by controlling the ignition device 24 to ignite it during the dragging process that continues after step S16. Afterward, CPU 91 advances the process to step S22.

[0062] In step S22, the CPU 91 determines whether the internal combustion engine 10 has completed starting. Specifically, first, the CPU 91 calculates the rotational speed of the crankshaft 13 based on the rotational phase SC of the crankshaft 13. Next, the CPU 91 determines whether the rotational speed of the crankshaft 13 has reached or exceeded a predetermined speed. The predetermined speed, which is considered the rotational speed of the crankshaft 13 when the internal combustion engine 10 is considered to have completed starting, is predetermined through testing and simulation. If the internal combustion engine 10 has not completed starting (S22: No), the CPU 91 returns the process to step S20. On the other hand, if the internal combustion engine 10 has completed starting (S22: Yes), the CPU 91 advances the process to step S22.

[0063] In step S23, CPU 91 terminates the drag processing. Specifically, CPU 91 stops applying torque from the first electric generator 71 to the crankshaft 13. Afterward, CPU 91 terminates a series of processes.

[0064] <Handling when the unit is not in a cold state>

[0065] exist Figure 3 When a negative determination is made in step S11 or step S12, CPU91 advances the processing to... Figure 4 The step S30 is shown. Specifically, when the catalyst temperature TC is above the cold engine catalyst temperature TCL (S11: No), or when the cooling water temperature TW is above the cold engine cooling water temperature TWL, the CPU91 advances the process to step S30. That is, when the catalyst 27 is in an activated state, or when the internal combustion engine 10 is not in a cold engine state, the CPU91 advances the process to step S30.

[0066] like Figure 4 As shown, in step S30, CPU 91 begins the dragging process. During the dragging process, CPU 91 controls the first electric generator 71 to drag the internal combustion engine 10. The process in step S30 is the same as that in step S16 described above. Furthermore, CPU 91 continues this dragging process after step S30. Then, CPU 91 advances the process to step S31.

[0067] In step S31, CPU 91 performs intake gas flow adjustment processing. CPU 91 controls throttle valve 22, adjusting its opening to the open state. In step S31, the opening of throttle valve 22 is adjusted such that the mass of air supplied to combustion chamber R per unit time divided by the required amount DA becomes the target air-fuel ratio. In step S31, the gas flow rate per unit time flowing in intake passage 21 is greater than the second gas flow rate V2 by an amount corresponding to the lack of air supplied from evaporative fuel passage 32 to intake passage 21. Therefore, the opening of throttle valve 22 becomes a larger value than the opening of throttle valve 22 in step S15. Then, CPU 91 advances the process to step S32.

[0068] In step S32, CPU 91 begins to drive the fuel injection device 23. CPU 91 drives the fuel injection device 23 in a manner that supplies liquid fuel corresponding to the required amount DA to the combustion chamber R. Afterwards, CPU 91 advances the process to step S33.

[0069] In step S33, CPU 91 performs a second start-up process. In this process, CPU 91 starts the internal combustion engine 10 by driving the fuel injection device 23 to supply liquid fuel to the combustion chamber R and simultaneously controlling the ignition device 24 to ignite it. Afterward, CPU 91 advances the process to step S34.

[0070] In step S34, CPU 91 determines whether the internal combustion engine 10 has completed starting. The details are the same as in step S22. If the internal combustion engine 10 has not completed starting (S34: No), CPU 91 returns the process to step S33. On the other hand, if the internal combustion engine 10 has completed starting (S34), CPU 91 advances the process to step S35.

[0071] In step S35, CPU 91 terminates the drag processing. Specifically, CPU 91 stops applying torque from the first electric generator 71 to the crankshaft 13. Afterward, CPU 91 terminates a series of processes.

[0072] In this way, when the internal combustion engine 10 is not in a cold state, the CPU 91 does not execute the evaporative fuel adjustment process and the first start process in the drag process, but executes the second start process, thereby starting the internal combustion engine 10.

[0073] <Handling when the maximum supply does not meet the demand>

[0074] exist Figure 3 When a negative decision is made in step S14, CPU91 advances the processing to... Figure 5The step S41 is shown. Specifically, when the first gas flow rate V1 is greater than the maximum gas flow rate VL (S14: No), the CPU 91 advances the process to step S41. That is, when the maximum supply amount SAL is less than the required amount DA, the CPU 91 advances the process to step S41.

[0075] like Figure 5 As shown, in step S41, CPU 91 calculates the insufficient fuel amount SA. Specifically, CPU 91 calculates the insufficient fuel amount SA by subtracting the maximum supply amount SAL from the required amount DA. Then, CPU 91 advances the process to step S42.

[0076] In step S42, CPU 91 performs intake gas flow adjustment processing. CPU 91 controls throttle valve 22, adjusting its opening to the open state. In step S42, the opening of throttle valve 22 is adjusted such that the mass of air supplied to combustion chamber R per unit time divided by the required amount DA becomes the target air-fuel ratio. Afterwards, CPU 91 advances the process to step S43.

[0077] Steps S43 to S47 are the same processes as those described in steps S16 to S20. Therefore, detailed explanations are omitted. Furthermore, in step S46, the evaporative fuel regulating valve 34 is fully open. Therefore, the mass of evaporative fuel supplied to the intake passage 21 per unit time becomes the maximum supply quantity SAL. Thus, the mass of evaporative fuel supplied to the intake passage 21 per unit time is in a state that, although not exactly the required quantity DA, is as close as possible to the required quantity DA. After step S47, the CPU 91 advances the process to step S48.

[0078] In step S48, CPU 91 performs additional injection processing. Specifically, CPU 91 starts driving the fuel injection device 23. Then, CPU 91 drives the fuel injection device 23 in a manner that supplies liquid fuel corresponding to the shortfall fuel amount SA to the combustion chamber R per unit time. After that, CPU 91 advances the process to step S49.

[0079] The processing in steps S49 to S51 is the same as that in steps S21 to S23. Therefore, detailed explanation is omitted. After step S51, CPU91 ends the series of processes.

[0080] <Handling when the intake negative pressure does not reach the required negative pressure>

[0081] exist Figure 3 When a negative decision is made in step S18 as shown, or in Figure 5 When a negative decision is made in step S45, CPU91 proceeds to... Figure 6The step S61 is shown. Specifically, when the intake negative pressure PI is not reduced to the required negative pressure PN, the CPU91 proceeds to step S61.

[0082] like Figure 6 As shown, in step S61, the CPU 91 performs intake gas flow rate adjustment processing. The processes in steps S61 to S65 are the same as those in steps S31 to S35. Therefore, detailed explanation is omitted. Then, after the processing in step S65, the CPU 91 ends the series of processes.

[0083] (The role of the implementation method)

[0084] According to the above embodiment, after the CPU 91 starts the drive process, the first electric generator 71 drives the internal combustion engine 10. As a result, a negative pressure is generated in the combustion chamber R. Furthermore, after a predetermined time ST, the intake negative pressure PI becomes smaller than the required negative pressure PN. Using the intake negative pressure PI, air flows together with the evaporated fuel from the evaporation fuel passage 32 to the intake passage 21.

[0085] (Effects of the implementation method)

[0086] (1) According to the above embodiment, the internal combustion engine 10 is driven by the first electric generator 71 to generate an intake negative pressure PI. Using the intake negative pressure PI, evaporative fuel can be supplied to the combustion chamber R. Furthermore, by adjusting the evaporative fuel supply, the amount of evaporative fuel supplied to the combustion chamber R can be controlled to a level suitable for starting the internal combustion engine 10. Therefore, in starting the internal combustion engine 10 by burning the evaporative fuel, a device solely for supplying evaporative fuel, such as a booster pump for feeding the evaporative fuel, is not required.

[0087] (2) According to the above embodiment, in the evaporative fuel adjustment process, the opening of the evaporative fuel adjustment valve 34 is adjusted so that the mass of evaporative fuel supplied to the intake passage 21 per unit time is close to the required amount DA. Furthermore, in the intake gas flow adjustment process, the opening of the throttle valve 22 is adjusted so that the value obtained by dividing the mass of air supplied to the combustion chamber R per unit time by the required amount DA is the target air-fuel ratio. Therefore, through the intake gas flow adjustment process and the evaporative fuel adjustment process, air and evaporative fuel are supplied to the combustion chamber R to achieve the target air-fuel ratio. As a result, when the internal combustion engine 10 is started, it is possible to prevent the air-fuel ratio from becoming extremely lean or extremely rich.

[0088] (3) According to the above embodiment, when the maximum supply quantity SAL does not meet the required quantity DA, the CPU91 performs additional injection. Through this additional injection, liquid fuel is supplied to the combustion chamber R even when the required quantity DA is insufficient by vaporized fuel alone. Therefore, in terms of starting the internal combustion engine 10, fuel insufficiency can be suppressed.

[0089] (4) According to the above embodiment, in the additional injection process, the CPU 91 drives the fuel injection device 23 to supply liquid fuel corresponding to the insufficient fuel amount SA to the combustion chamber R per unit time. That is, when the internal combustion engine 10 is started, even if the required amount DA is not met by evaporating fuel alone, liquid fuel corresponding to the required amount DA can be added. As a result, when the internal combustion engine 10 is started, fuel that is neither excessive nor insufficient relative to the required amount DA can be supplied.

[0090] (5) When the internal combustion engine 10 is in a cold state, the heavy components of the fuel exist as liquid fuel. If liquid fuel is used to start the internal combustion engine 10 at this time, combustion may become unstable, or harmful substances may be easily emitted. In the above embodiment, when the internal combustion engine 10 is in a cold state, evaporative fuel is used to start the internal combustion engine 10. Therefore, evaporative fuel with fewer heavy components can be used to start the internal combustion engine 10.

[0091] On the other hand, when the internal combustion engine 10 is not in a cold state, the heavy components in the fuel are difficult to exist as liquid fuel, so the possibility of unstable combustion or easy emission of harmful substances is low. According to the above embodiment, when the internal combustion engine 10 is not in a cold state, the CPU 91 does not execute the evaporative fuel adjustment process and the first start-up process in the drive process, but executes the second start-up process. That is, when the internal combustion engine 10 is not in a cold state, the internal combustion engine 10 is started without using evaporative fuel. In this case, liquid fuel is supplied before and after the internal combustion engine 10 is started. Therefore, fuel can be supplied before and after the internal combustion engine 10 is started without significantly changing the fuel properties.

[0092] (Other implementation methods)

[0093] The above-described embodiments can be implemented by modification as follows. The above-described embodiments and the following modifications can be combined with each other to implement them within the scope of technical inconsistency.

[0094] In the internal combustion engine 10, the fuel injection device 23 can be either a device that directly injects liquid fuel into the combustion chamber R, or a device that injects liquid fuel into the intake passage 21 and supplies the injected liquid fuel to the combustion chamber R together with the intake gas.

[0095] • The fuel supply mechanism 30 may also be without the shut-off valve 33. Even if the shut-off valve 33 is omitted, the flow rate of the gas flowing in the evaporative fuel passage 32 can be adjusted by adjusting the opening of the evaporative fuel regulating valve 34.

[0096] The fuel supply mechanism 30 may also include a vaporization promoting device. This device is located inside the fuel tank 31 and promotes the vaporization of the liquid fuel within the fuel tank 31. For example, the vaporization promoting device may be a device that uses ultrasound to promote the vaporization of the liquid fuel.

[0097] The fuel tank 31 may also have a vaporization chamber for storing evaporative fuel, in addition to a storage chamber for storing liquid fuel. If the fuel tank 31 is only a storage chamber, and the entire space of the storage chamber is filled with liquid fuel, then there is no space for evaporative fuel to exist. This can be addressed by not storing liquid fuel in the vaporization chamber, allowing a suitable amount of evaporative fuel to be stored in the fuel tank 31.

[0098] In the fuel supply mechanism 30, the evaporative fuel passage 32 can also branch corresponding to the number of combustion chambers R. In this example, each branched evaporative fuel passage 32 can be connected to a branched intake passage 21. Furthermore, in this modified example, an on / off valve can be installed in each branched evaporative fuel passage 32. Thus, evaporative fuel can be supplied to each combustion chamber R at an appropriate timing.

[0099] The control device 90 may also be configured as a circuit including one or more processors that perform various processes according to a computer program (software). Furthermore, the control device 90 may also be configured as a circuit including one or more dedicated hardware circuits, such as an application-specific integrated circuit (ASIC), that performs at least a portion of the various processes, or a combination thereof. The processor includes a CPU and memories such as RAM and ROM. The memories store program code or instructions configured to cause the CPU to perform processes. Memory, or computer-readable medium, includes all available media that can be accessed by a general-purpose or special-purpose computer.

[0100] • The control device 90 can also obtain the evaporative fuel concentration CF independently of the evaporative fuel concentration sensor 83. For example, assuming the storage device 94 pre-stores the vapor pressure characteristics of the liquid fuel stored in the fuel tank 31, and the hybrid vehicle 100 has a tank temperature sensor that detects the temperature inside the fuel tank 31. In this case, the CPU 91 can also obtain the evaporative fuel concentration CF by calculating it based on the vapor pressure characteristics of the liquid fuel and the temperature inside the fuel tank 31. Alternatively, for example, assuming the hybrid vehicle 100 has a pressure sensor that detects the pressure inside the fuel tank 31 and an oxygen concentration sensor that detects the oxygen concentration inside the fuel tank 31. In this case, the CPU 91 can also detect the evaporative fuel concentration CF by calculating it based on the pressure inside the fuel tank 31 and the oxygen concentration inside the fuel tank 31.

[0101] • When the hybrid vehicle 100 is running using the first electric generator 71 and the second electric generator 72, and a request to start the internal combustion engine 10 is received, the CPU 91 can initiate the internal combustion engine starting procedure PS. In this case, the probability that the accelerator operation amount ACC is detected to be large and the first gas flow rate V1 is calculated to be large increases. Therefore, in such a case, it is easy to obtain a significant improvement in handling situations where the maximum supply amount SAL is smaller than the first gas flow rate V1.

[0102] • In the evaporative fuel adjustment process in step S19, when adjusting the opening of the evaporative fuel adjustment valve 34, the CPU 91 does not need to ensure that the mass of evaporative fuel per unit time is consistent with the required amount DA. Even if the mass of evaporative fuel per unit time is not necessarily consistent with the required amount DA, the CPU 91 can adjust the opening of the evaporative fuel adjustment valve 34 in a manner that brings the mass of evaporative fuel per unit time close to the required amount DA through the process in step S19. Furthermore, in the evaporative fuel adjustment process, the CPU 91 can also adjust the opening of the evaporative fuel adjustment valve 34 independently of the required amount DA. For example, in the evaporative fuel adjustment process, the CPU 91 can adjust the opening of the evaporative fuel adjustment valve 34 to a preset fixed opening suitable for starting the internal combustion engine 10.

[0103] • In the intake gas flow adjustment process in step S15, the CPU91 can also adjust the opening of the throttle valve 22 regardless of the required amount DA. For example, in the intake gas flow adjustment process, the CPU91 can adjust the opening of the throttle valve 22 in a way that is a preset fixed opening suitable for starting the internal combustion engine 10.

[0104] • In the additional injection process, the CPU91 may not supply liquid fuel corresponding to the insufficient fuel amount SA from the fuel injection device 23. When the maximum supply amount SAL does not meet the required amount DA, the degree of fuel shortage can be suppressed by supplying liquid fuel slightly from the fuel injection device 23.

[0105] Furthermore, in the fuel injection device 23, there exists a minimum fuel injection quantity that ensures the correct amount of fuel injection. When the minimum fuel injection quantity that the fuel injection device 23 can supply per combustion cycle is set as the minimum injection quantity, sometimes the value obtained by adding the amount that can be supplied at the minimum injection quantity per unit time to the maximum supply quantity SAL exceeds the required quantity DA. In this case, during the additional injection process, the CPU 91 can also supply liquid fuel to the combustion chamber R at the minimum injection quantity. Moreover, during the intake gas adjustment process, the CPU 91 can adjust the opening of the throttle valve 22 in such a way that the mass of vaporized fuel supplied to the intake passage 21 per unit time is the value obtained by subtracting the amount that can be supplied at the minimum injection quantity per unit time from the required quantity DA. Accordingly, the total amount of liquid fuel and vaporized fuel supplied to the combustion chamber R becomes the required quantity DA. Therefore, by means of the additional injection process, even when liquid fuel is supplied to the combustion chamber R, combustion can be achieved at the target air-fuel ratio.

[0106] • The CPU91 can also refrain from additional injection when the maximum supply quantity SAL does not meet the required quantity DA. In this case, the CPU91 can start the internal combustion engine 10 using only liquid fuel, without using evaporated fuel, when the maximum supply quantity SAL does not meet the required quantity DA. In other words, the CPU91 can also perform a second start-up process when the maximum supply quantity SAL does not meet the required quantity DA.

[0107] In the above embodiment, CPU91 may perform the first startup process regardless of the result of the cold-system determination process. Alternatively, CPU91 may choose not to perform the cold-system determination process.

[0108] The system of the hybrid vehicle 100 is not limited to the examples of the above embodiments, as long as it can rotate the crankshaft 13 by an electric generator to drive the internal combustion engine 10.

Claims

1. A hybrid vehicle comprising an internal combustion engine as a drive source, an evaporative fuel passage, an evaporative fuel regulating valve, an electric generator, and a control device. The internal combustion engine has the following features: The main body of the internal combustion engine has a combustion chamber; A fuel injection device configured to supply liquid fuel to the combustion chamber; The ignition device is configured to ignite the combustion chamber for combustion to occur therein; An intake passage, connected to the combustion chamber, is configured to allow intake gas to flow into the combustion chamber; and A throttle valve, located in the intake passage, is configured to adjust the flow rate of the intake gas, i.e., the intake air flow rate. The evaporative fuel passage connects from the fuel tank to the portion of the intake passage between the throttle valve and the combustion chamber, configured such that the evaporative fuel generated in the fuel tank flows together with air into the intake passage. The evaporative fuel regulating valve is disposed in the evaporative fuel passage and is configured to adjust the opening degree of the evaporative fuel passage. The electric generator is capable of rotating the crankshaft of the internal combustion engine without injecting the liquid fuel from the fuel injection device. The control device is configured to control the starting of the internal combustion engine by controlling the ignition device, the throttle valve, the evaporative fuel regulating valve, and the electric generator as controlled objects. The control device is configured to execute: The intake gas flow rate is adjusted to control the throttle valve opening to the open state; The towing process involves controlling the electric generator to drive the internal combustion engine; and When a predetermined time has elapsed since the start of the dragging process, it is determined whether the negative pressure of the evaporative fuel passage, i.e. the intake negative pressure, is smaller than the pressure at which gas can be supplied from the evaporative fuel passage, i.e. the required negative pressure. In the process of determining whether the intake negative pressure is smaller than the required negative pressure, if it is determined that the intake negative pressure is smaller than the required negative pressure, the control device is configured to execute: The evaporative fuel adjustment process allows the evaporative fuel to flow in the evaporative fuel passage by adjusting the opening of the evaporative fuel adjustment valve during the dragging process. as well as The first starting process starts the internal combustion engine by controlling the ignition device to ignite it during the dragging process. as well as In the process of determining whether the intake negative pressure is lower than the required negative pressure, if it is determined that the intake negative pressure is higher than the required negative pressure, the control device does not execute the evaporative fuel adjustment process and the first start process in the drag process, but executes the second start process. The liquid fuel is supplied to the combustion chamber by driving the fuel injection device, and the ignition device is controlled to ignite the internal combustion engine.

2. The hybrid vehicle according to claim 1, The evaporative fuel adjustment process includes adjusting the opening of the evaporative fuel adjustment valve in such a manner that the mass of evaporative fuel supplied to the intake passage per unit time is close to the required mass of fuel per unit time for starting the internal combustion engine. The intake gas flow rate adjustment process includes adjusting the throttle opening such that the mass of air supplied to the combustion chamber divided by the required amount becomes the target air-fuel ratio.

3. The hybrid vehicle according to claim 2, When the maximum supply amount is set as the mass of evaporated fuel supplied to the intake passage per unit time when the opening of the evaporated fuel regulating valve is fully open, if the maximum supply amount does not meet the required amount, The control device is configured to, in addition to the evaporative fuel adjustment process, also perform an additional injection process by driving the fuel injection device to supply fuel to the combustion chamber.

4. The hybrid vehicle according to claim 3, The additional injection process includes supplying an amount obtained by subtracting the maximum supply amount from the fuel injection device per unit time.

5. The hybrid vehicle according to claim 3, When the minimum fuel injection amount that the fuel injection device can supply per combustion cycle is set as the minimum injection amount, If the value obtained by adding the amount that can be supplied at the minimum injection rate per unit time to the maximum supply amount exceeds the required amount, The additional injection process includes supplying the fuel to the combustion chamber at the minimum injection quantity. The evaporative fuel adjustment process includes adjusting the throttle opening such that the mass of the evaporative fuel supplied to the intake passage per unit time is a value obtained by subtracting the amount that can be supplied per unit time at the minimum injection quantity from the required amount.

6. The hybrid vehicle according to any one of claims 1 to 5, The control device is configured to further perform a cold engine determination process, which determines whether the internal combustion engine is in a cold engine state where the temperature is below a preset predetermined temperature. If the internal combustion engine is determined to be in a cold engine state during the cold engine determination process, the control device is configured to execute the drag process, the evaporative fuel adjustment process within the drag process, and the first start-up process. If the internal combustion engine is determined to be not in the cold engine state during the cold engine determination process, the control device is configured to execute the second start process instead of the evaporative fuel adjustment process and the first start process in the drag process.

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