Control device of vehicle and control method of vehicle

Abstract

This invention provides a vehicle control device and a vehicle control method. When the ignition switch is turned off before the engine speed reaches its autonomous operating speed (i.e., the autonomous speed), the vehicle control device performs a rising process, and after the rising process is completed, it performs a stop position control. The rising process involves increasing the engine speed until it reaches a speed above the autonomous speed. The stop position control uses an electric generator to convert the rotational energy of the engine crankshaft into electrical energy for regenerative braking, thereby stopping the piston in the cylinder at a predetermined position.

Description

Technical Field

[0001] This disclosure relates to vehicle control devices and vehicle control methods. Background Technology

[0002] Japanese Patent Application Publication No. 2005-180288 discloses a vehicle control device that performs idle speed shutdown control. Idle speed shutdown control is a control that stops the engine by cutting off the fuel supply when specified stopping conditions are met. Specified stopping conditions include, for example, when the vehicle speed reaches 0, the gear is in neutral or park, the brake is depressed, and / or the parking brake is engaged. For example, a situation where the engine stops while waiting at a traffic light can be considered.

[0003] When the engine is stopped, the aforementioned control device controls the engine to stop at a predetermined position midway through the compression stroke of any cylinder. This cylinder is filled with a fuel-air mixture. When the engine is restarted, the control device drives the piston to a position near top dead center via an electric generator. The control device then ignites the mixture via a spark plug.

[0004] The aforementioned control device controls the piston's stopping position in a manner that reduces the required torque of the electric generator when the engine is restarted. Specifically, the control device stops the piston in the compression stroke at a position 60 to 90 degrees closer to the crankshaft angle than the top dead center position.

[0005] The engine speed at idle is above the lower limit of the engine speed at which it can operate autonomously. Here, it's possible to consider stopping the engine after it has started but before it reaches a state where it can operate autonomously. For example, one could consider turning off the ignition switch immediately after starting the engine, thereby stopping it. In such a situation, it becomes difficult to control the piston to stop at the desired position. The reasons will be explained below.

[0006] If the engine stops running, the engine speed decreases due to the compression reaction force of the air filling the cylinders, and the crankshaft stops. During the decrease in engine speed, stop position control is performed to control the stopping position of the piston. Stop position control uses an electric generator to convert the rotational energy of the crankshaft into electrical energy for regenerative braking, thereby adjusting the stopping position of the piston.

[0007] In the initial stage after starting the engine and before it reaches autonomous operation, the airflow into the cylinder through the intake passage is unstable, resulting in significant variations in the amount of air filling the cylinder. Therefore, if the engine stops starting before reaching autonomous operation, the compression reaction force of the air filling the cylinder is uneven, making it difficult to perform stop position control based on the electric generator.

[0008] In contrast, when the engine speed is high enough that the engine can operate autonomously, the variation in the amount of air filling the cylinder decreases. Therefore, the magnitude of the repulsive force caused by the air in the cylinder can be estimated. It is possible to estimate how the piston's stop position should be controlled taking into account the magnitude of this air repulsive force. That is, in such a situation, the control device can easily control the piston's stop position by controlling the magnitude of the negative torque of the electric generator using the detection value of the crankshaft angle sensor.

[0009] Therefore, if the engine is stopped shortly after starting and before its speed has sufficiently increased, it may be difficult to bring the piston to the desired position. Furthermore, stopping the engine before its speed has fully increased makes it difficult to ensure control before the engine speed reaches zero. In other words, there are fewer opportunities to adjust the magnitude of the negative torque of the electric generator to control the piston's stopping position. Summary of the Invention

[0010] According to one aspect of this disclosure, a vehicle control device is provided, the vehicle having an engine with cylinders and an electric generator connected to the engine, wherein the vehicle control device includes a processing circuit configured to perform an increase process when the ignition switch is turned off before the engine speed increases to a speed at which the engine can operate autonomously, i.e., an autonomous speed, and to perform a stop position control after the increase process is completed, the increase process being a process of increasing the engine speed until the engine speed becomes higher than the autonomous speed, and the stop position control being a control that stops the piston in the cylinder at a predetermined position by converting the rotational energy of the crankshaft of the engine into electrical power through the electric generator for regenerative braking.

[0011] According to one aspect of this disclosure, a vehicle control method is provided. The vehicle includes an engine with cylinders and an electric generator connected to the engine. The vehicle control method includes the following steps: when the ignition switch is turned off before the engine speed rises to a speed at which the engine can operate autonomously (i.e., an autonomous speed), an upward process is performed, and after the upward process is completed, a stop position control is performed. The upward process is a process of increasing the engine speed until the engine speed becomes higher than the autonomous speed. The stop position control is a control that uses the electric generator to convert the rotational energy of the crankshaft of the engine into electricity for regenerative braking, thereby stopping the piston in the cylinder at a predetermined position. Attached Figure Description

[0012] Figure 1 This is a schematic diagram illustrating a control device according to one embodiment and a hybrid vehicle that is the object controlled by the control device.

[0013] Figure 2 It means Figure 1 A schematic diagram of one of the multiple cylinders shown.

[0014] Figure 3 It is a diagram representing the combustion cycle.

[0015] Figure 4 yes Figure 1 The flowchart shows the process executed by the control device.

[0016] Figure 5 This is a timeline illustrating the function of this embodiment. (a) indicates whether the ignition switch is on or off, (b) indicates the engine speed, and (c) indicates whether the engine start-up flag is ON or OFF.

[0017] Figure 6 This is a flowchart of the change example processing. Detailed Implementation

[0018] Hereinafter, with reference to the accompanying drawings, a vehicle control device according to one embodiment will be described.

[0019] <Regarding the structure of hybrid vehicle 100>

[0020] Figure 1The control object of the control device 34, as shown in one embodiment, is a hybrid vehicle (hereinafter referred to as a vehicle) 100. The control device 34 is mounted on the vehicle 100. The vehicle 100 includes an internal combustion engine (hereinafter referred to as an engine) 10 and an electric generator 12. An air conditioning compressor (hereinafter referred to as an AC compressor) 14 is mounted on the vehicle 100. The engine 10 has a crankshaft pulley 10a. The electric generator 12 has an electric generator pulley 12a. The AC compressor 14 has an AC compressor pulley 14a. The crankshaft pulley 10a, the electric generator pulley 12a, and the AC compressor pulley 14a are interconnected via a belt 16.

[0021] Thus, in vehicle 100, engine 10 and electric generator 12 are interconnected via belt 16. Control device 34 controls vehicle 100.

[0022] In addition, the vehicle 100 includes a transmission 18, a starter 20, a DC-DC converter 22, an auxiliary machine 24, a high-voltage battery 26, and a low-voltage battery 28. The high-voltage battery 26 is, for example, a Li-ion battery. The low-voltage battery 28 is, for example, a lead-acid battery. The transmission 18 is connected to the engine 10. The starter 20 is connected to the transmission 18. The starter 20 can drive the transmission 18. By using the starter 20 to drive the transmission 18, the engine 10 can be started. The high-voltage battery 26 is connected to an electric generator 12 and the DC-DC converter 22. The electric generator 12 can start the engine 10 by receiving power from the high-voltage battery 26. The low-voltage battery 28 is connected to the starter 20, the DC-DC converter 22, and the auxiliary machine 24.

[0023] like Figure 1 As shown, engine 10 has four cylinders: #1, #2, #3, and #4. Figure 2 It means Figure 1 A schematic diagram of one of the four cylinders #1 to #4 shown.

[0024] Intake passage 54 is connected to cylinders #1 to #4. Intake passage 54 introduces intake air from outside the engine 10 into cylinders #1 to #4 respectively. Exhaust passage 60 is connected to cylinders #1 to #4. Exhaust air is discharged from cylinders #1 to #4 to outside the engine 10 respectively.

[0025] Throttle valve 56 is located in the middle of intake passage 54. Throttle valve 56 adjusts the amount of intake air flowing in intake passage 54. Intake injection valve 58 is located near the cylinder in intake passage 54. Intake injection valve 58 supplies fuel to the cylinder via intake passage 54 by injecting fuel into intake passage 54.

[0026] Piston 48 is located inside the cylinder. Piston 48 is connected to crankshaft 52 via connecting rod 50.

[0027] Regarding cylinders #1 to #4, when the intake valve 40 opens, the drawn-in air flows into the combustion chamber 38. Fuel is injected into the combustion chamber 38 through the in-cylinder injection valve 44. In the combustion chamber 38, the air-fuel mixture is burned by a spark discharge based on the ignition device 46. As the fuel-air mixture burns in the cylinder, the piston 48 reciprocates inside the cylinder. The energy generated by combustion is extracted as rotational energy for the crankshaft 52 of the engine 10. The crankshaft 52 of the engine 10 is connected to the transmission 18. The air-fuel mixture supplied for combustion is discharged from the combustion chamber 38 when the exhaust valve 42 opens.

[0028] The control device 34 includes a so-called microcomputer with a CPU, ROM, RAM, and input / output interfaces. The control device 34 utilizes the temporary storage function of RAM and performs signal processing according to a program pre-stored in the ROM. The control device 34 is capable of controlling the engine 10 and the electric generator 12, etc.

[0029] A crankshaft angle sensor 30 is installed on the engine 10. The control device 34 obtains the crankshaft angle through the crankshaft angle sensor 30. By performing time differentiation on the obtained crankshaft angle, the control device 34 obtains the engine speed of the engine 10. An electric generator speed sensor 32 is installed on the electric generator 12. The control device 34 obtains the speed of the electric generator 12 through the electric generator speed sensor 32.

[0030] Ignition switch 35 is located in vehicle 100. Control device 34 can obtain a signal from ignition switch 35 indicating whether ignition switch 35 is on or off.

[0031] A vehicle speed sensor 36 for detecting the speed of vehicle 100 is installed on vehicle 100. Control device 34 can obtain a signal indicating the speed of vehicle 100 from vehicle speed sensor 36.

[0032] <The load acting on the electric generator 12 when the generator 12 starts the engine 10>

[0033] Imagine a scenario where the electric generator 12 starts the engine 10 from a state where the engine speed is 0.

[0034] like Figure 3 As shown, when the crankshaft angle is 0–180 degrees, cylinder #1 is in the expansion stroke. When the crankshaft angle is 180–360 degrees, cylinder #1 is in the exhaust stroke. When the crankshaft angle is 360–540 degrees, cylinder #1 is in the intake stroke. When the crankshaft angle is 540–720 degrees, cylinder #1 is in the compression stroke.

[0035] like Figure 3As shown, when the crankshaft angle is 0–180 degrees, cylinder #2 is in the exhaust stroke. When the crankshaft angle is 180–360 degrees, cylinder #2 is in the intake stroke. When the crankshaft angle is 360–540 degrees, cylinder #2 is in the compression stroke. When the crankshaft angle is 540–720 degrees, cylinder #2 is in the expansion stroke.

[0036] like Figure 3 As shown, when the crankshaft angle is 0–180 degrees, cylinder #3 is in the compression stroke. When the crankshaft angle is 180–360 degrees, cylinder #3 is in the expansion stroke. When the crankshaft angle is 360–540 degrees, cylinder #3 is in the exhaust stroke. When the crankshaft angle is 540–720 degrees, cylinder #3 is in the intake stroke.

[0037] like Figure 3 As shown, when the crankshaft angle is 0–180 degrees, cylinder #4 is in the intake stroke. When the crankshaft angle is 180–360 degrees, cylinder #4 is in the compression stroke. When the crankshaft angle is 360–540 degrees, cylinder #4 is in the expansion stroke. When the crankshaft angle is 540–720 degrees, cylinder #4 is in the exhaust stroke.

[0038] Thus, regardless of the crankshaft angle, one of the four cylinders #1 to #4 is in the compression stroke, and the other one is in the expansion stroke. In the cylinder in the compression or expansion stroke, the intake valve 40 and exhaust valve 42 are closed. Therefore, when the electric generator 12 starts the engine 10, the piston 48 in the cylinder in the compression or expansion stroke is difficult to move. That is, a load is applied to the electric generator 12. For example, if the electric generator 12 starts driving the engine 10 from a crankshaft angle of 0 degrees, a load is applied to the electric generator 12, primarily due to cylinders #1 and #3.

[0039] Consider the case where piston 48 is at bottom dead center at the start of the engine start-up process, which raises the engine speed from 0. In this case, the electric generator 12 needs to move piston 48 from the start of the compression stroke to the end of the compression stroke. During the compression stroke, intake valve 40 and exhaust valve 42 are closed, so the load acting on the electric generator 12 due to the repulsive force of compressed air is large.

[0040] <Processing performed by control device 34>

[0041] Reference Figure 4 ,illustrate Figure 1 The control device 34 performs the processing. The control device 34 is triggered by the fulfillment of the logical product condition of the ignition switch 35 being on and the engine speed being 0. Figure 4The process is illustrated. For example, control device 34 turns on ignition switch 35 when vehicle 100 is stopped, thereby initiating the process. Figure 4 The process is as shown. Furthermore, by having the engine speed reach 0 with the ignition switch 35 on, the control device 34 begins... Figure 4 The processing shown.

[0042] In step S400, control device 34 determines whether the execution conditions for engine starting processing are met. If control device 34 makes a negative determination in step S400 (step S400: No), step S400 is repeated. If control device 34 makes a positive determination in step S400 (step S400: Yes), the process proceeds to step S402. In step S402, control device 34 begins engine starting processing.

[0043] This section explains the engine starting process. Engine starting process refers to the process of increasing the engine speed from 0 to the speed at which the engine 10 can operate autonomously, i.e., the autonomous speed. First, the control device 34 starts the crankshaft of the engine 10 via the electric generator 12. Furthermore, if the combustion initiation condition is met when the crankshaft 52 rotates due to crankshaft starting, the control device 34 initiates fuel injection control and ignition control of the engine 10. The combustion initiation condition means that stable combustion can occur in the engine 10. Stable combustion occurs because the piston 48 descends at a certain speed and a certain amount of air flows into the cylinder. Therefore, the combustion initiation condition is, for example, a condition where the engine speed is above a lower limit.

[0044] This describes the execution conditions for starting the engine immediately after the ignition switch 35 is turned on when the vehicle 100 is stopped.

[0045] When the control device 34 turns on the ignition switch 35 while the vehicle 100 is stopped, it determines whether the rapid idle shutdown condition is met. In this embodiment, the rapid idle shutdown condition refers to the situation where all of the following conditions (A), (B), (C), and (D) are met: (A) The vehicle 100 stops from the time the ignition switch 35 is turned on. (B) The high-voltage battery 26 has a charging rate of at least a first charging rate threshold and the low-voltage battery 28 has a charging rate of at least a second charging rate threshold. (C) The engine 10 is not required to warm up. (D) The evaporator temperature is below a specified temperature. The rapid idle shutdown condition not being met means that at least one of conditions (A), (B), (C), and (D) is not met.

[0046] If the rapid idle shutdown condition is not met, the control device 34 determines that the execution condition for the engine starting process is met (step S400: Yes). That is, the control device 34 starts the engine starting process when the rapid idle shutdown condition is no longer met. As will be described later, there is a situation where the rapid idle shutdown process is prohibited at the moment the ignition switch 35 is turned on. In the above case, the control device 34 starts the engine starting process immediately after the ignition switch 35 is turned on.

[0047] If the rapid idle shutdown condition is met, the control device 34 determines that the execution condition for the engine starting process is not met (step S400: No). If the rapid idle shutdown condition is met, the control device 34 executes the rapid idle shutdown process. The rapid idle shutdown process is the process of maintaining the engine speed at 0 from the time the ignition switch 35 is turned on.

[0048] This section explains the execution conditions for the engine starting process when the engine speed is 0 while the ignition switch 35 is on. Imagine the ignition switch 35 is on and the engine 10 is running. When a predetermined stopping condition is met—that the brake is engaged and the vehicle 100 remains stopped for a predetermined period—the control device 34 automatically stops the engine 10. That is, the engine speed is 0 while the ignition switch 35 is on. If the brake is released, the control device 34 determines that the execution conditions for the engine starting process are met (step S400: Yes). If the brake remains engaged, the control device 34 determines that the execution conditions for the engine starting process are not met (step S400: No).

[0049] After initiating the engine start-up process in step S402, control device 34 proceeds to step S404. In step S404, control device 34 determines whether the engine speed is above the autonomous speed. The autonomous speed is the speed at which engine 10 can operate autonomously. If control device 34 makes a negative determination in step S404 (step S404: No), step S404 is repeated. If control device 34 makes a positive determination in step S404 (step S404: Yes), step S406 is proceeded. In step S406, control device 34 terminates the engine start-up process.

[0050] According to steps S402, S404, and S406, the engine starting process continues regardless of whether the ignition switch 35 is off during the execution of the engine starting process. That is, the control device 34 performs the rise process when the ignition switch 35 is off, before the engine speed rises to the autonomous speed. The rise process refers to the process of increasing the engine speed until the engine speed reaches or exceeds the autonomous speed. The rise process includes starting the crankshaft of the engine 10 via the electric generator 12 and performing combustion in the cylinders until the engine speed reaches or exceeds the autonomous speed. Here, even when the ignition switch 35 is off, the control device 34 continues to start the crankshaft and continue to perform combustion in the cylinders until the engine speed reaches or exceeds the autonomous speed. The control device 34 thus achieves the rise process.

[0051] After the engine starting process is completed in step S406, control device 34 proceeds to step S408. In step S408, control device 34 determines whether the ignition switch 35 is turned on. If control device 34 makes a positive determination in step S408 (step S408: Yes), the process ends. If control device 34 makes a negative determination in step S408 (step S408: No), the process proceeds to step S410.

[0052] In step S410, control device 34 performs stop position control. Thus, stop position control is performed after the rising process is completed. Stop position control is achieved by converting the rotational energy of the crankshaft 52 of the engine 10 into electrical energy via the electric generator 12 to perform regenerative braking, thereby stopping the piston 48 in the cylinder at a predetermined position. The predetermined position is a position within a predetermined range that excludes the vicinity of the top dead center and bottom dead center of the piston 48. For example, control device 34 stops the piston 48 with a crankshaft angle of 30 to 150 degrees. The stop position control is explained below. Regenerative braking is performed by the electric generator 12, thereby reducing the engine speed. That is, a torque, i.e., a negative torque, is applied to the engine 10 to reduce the rotation of the crankshaft 52 of the engine 10. Target control data representing the relationship between a target value of the crankshaft angle and a target value of the engine speed when stop position control is performed is preset. Control device 34 adjusts the magnitude of the negative torque according to the target control data.

[0053] After stopping the piston 48 in step S410, the control device 34 terminates the process. If the control device 34 fails to stop the piston 48 at the specified position during stop position control, the rapid idle shutdown process is prohibited. If the stop position control executed after the failure of stop position control is successful, the prohibition of rapid idle shutdown is lifted.

[0054] <The function of this implementation method>

[0055] Reference Figure 5 This explains the function of turning off the ignition switch 35 during the engine start-up process after a rapid idle shutdown.

[0056] like Figure 5 As shown in (a), at time T1, the ignition switch 35 switches from off to on. Figure 5 In the example shown, the rapid idle shutdown condition is met from time T1 to time T2. Therefore, the engine speed remains 0 from time T1 to time T2.

[0057] exist Figure 5 In the example shown, at time T2, the rapid idle shutdown condition no longer holds. Therefore, as Figure 5 As shown in (c), at time T2, the engine start-up process flag switches from off to on. Thus, the engine start-up process begins. Figure 5 As shown in (b), the engine speed starts to increase from 0 starting from time T2.

[0058] like Figure 5 As shown in (a) and (b), at time T3, the ignition switch 35 is turned off before the engine speed reaches the autonomous speed. Although the ignition switch 35 is off at time T3, the engine speed still increases from time T3 to time T4. That is, the control device 34 performs the aforementioned speed increase process from time T3 to time T4.

[0059] like Figure 5 As shown in (b), at time T4, the engine speed reaches its autonomous speed. Figure 5 As shown in (c), the engine start-up flag is turned OFF when the engine speed reaches the autonomous speed. Control device 34 performs the aforementioned stop position control from time T4 to time T5.

[0060] <Effects of this implementation method>

[0061] (1) If the engine speed rises above the autonomous speed, the flow of air into the cylinder through the intake passage 54 stabilizes, thus reducing the variation in the amount of air filling the cylinder. Therefore, according to the control device 34 described above, the compression reaction force of the air filling the cylinder becomes uniform when stop position control begins. Therefore, even if the ignition switch 35 is turned off before starting is complete, the control device 34 described above can stop the piston 48 at the desired position through stop position control.

[0062] (2) In the rising process, a comparative example where combustion in the cylinder is not performed can be considered. In the structure of the above embodiment, combustion in the cylinder is performed during the rising process. Therefore, according to the structure of the above embodiment, the rising process can be completed earlier than in the comparative example. Therefore, the user is less likely to feel discomfort from the engine speed continuing to rise even though the ignition switch 35 is off.

[0063] (3) In the above structure, in order to perform the rapid idle shutdown process, the stop position control needs to be successfully achieved during the previous journey. The journey refers to the period from the time when the ignition switch 35 is turned on to the time when the ignition switch 35 is turned off and the vehicle 100 stops operating.

[0064] Next, the relationship between rapid idle shutdown and stop position control will be explained. The crankshaft of engine 10 is started by the electric generator 12, thereby initiating engine starting after the rapid idle shutdown process. At the start of the engine starting process, with piston 48 at bottom dead center, the electric generator 12 needs to move piston 48 from the start of the compression stroke to its end. During the compression stroke, intake valve 40 and exhaust valve 42 are closed, resulting in a large load on the electric generator 12 due to the repulsive force of compressed air. To avoid excessive load on the electric generator 12, if the control device 34 fails to stop piston 48 at the specified position during stop position control, rapid idle shutdown is prohibited.

[0065] In structures that prohibit rapid idle shutdown when stopping the piston 48 at a predetermined position fails during stop position control, performing stop position control after the rise process is completed is particularly effective. That is, stop position control is easier to achieve, thus facilitating rapid idle shutdown. As a result, improved fuel economy can be expected.

[0066] <Example of Change>

[0067] This embodiment can be modified as follows. This embodiment and the following modifications can be combined and implemented to the extent that they are not technically contradictory.

[0068] In the above embodiment, the engine 10 and the electric generator 12 are interconnected via belt 16. Alternatively, the engine 10 and the electric generator 12 may be connected via one or more gears. Or, the engine 10 and the electric generator 12 may be connected via a clutch.

[0069] In the above embodiment, the number of cylinders is four. However, this is merely an example. The number of cylinders can be more than one.

[0070] In the above embodiment, no clutch is provided that can connect or disconnect the engine 10 from the crankshaft pulley 10a. However, a clutch may be provided between the engine 10 and the crankshaft pulley 10a.

[0071] In the above embodiment, the high-voltage battery 26 and the low-voltage battery 28 are mounted on the vehicle 100. However, this is merely an example. Any battery capable of supplying power to the electric generator 12 can be mounted on the vehicle 100.

[0072] The combustion cycle configuration can be modified appropriately. In the above embodiment, the air-fuel mixture is ignited in the order of cylinder #1, cylinder #3, cylinder #4, and cylinder #2. Alternatively, the air-fuel mixture can be ignited in the order of cylinder #1, cylinder #2, cylinder #4, and cylinder #3.

[0073] In the above embodiments, the rapid idle shutdown condition refers to the fulfillment of all of the above conditions (A), (B), (C), and (D). One or more of conditions (B), (C), and (D) may be omitted.

[0074] In the above embodiment, the engine starting process includes starting the crankshaft of the engine 10 by means of the electric generator 12. Alternatively or based on this, the engine starting process may also include starting the crankshaft of the engine 10 by means of driving the transmission 18 using the starter 20.

[0075] In the above embodiment, the start-up process includes starting the crankshaft of the engine 10 via the electric generator 12 and performing combustion in the cylinders until the engine speed reaches or exceeds the autonomous speed. That is, combustion in the cylinders continues until the engine start-up process ends. Alternatively, combustion in the cylinders can be stopped before the engine start-up process ends.

[0076] In the above embodiment, the stop position control is performed when the ignition switch 35 is turned off after the engine starting process is completed. The stop position control can also be performed if the aforementioned stop conditions are met.

[0077] Imagine that after a positive determination is made in step S408, the engine speed is above the autonomous speed. In this state, stop position control can be performed even when the ignition switch 35 is off.

[0078] In the above embodiments, such as Figure 4 As shown in steps S406 and S408, the control device 34 determines whether the ignition switch 35 is turned on after the engine starting process is completed. However, this is only an example. Figure 6As shown, the control device 34 can also determine whether the ignition switch 35 is turned on after the engine starting process has just begun (step S408a).

[0079] If the control device 34 makes a positive determination in step S408a (step S408a: Yes), it proceeds to step S404a. In step S404a, the control device 34 determines whether the engine speed is above the autonomous speed. If the control device 34 makes a negative determination in step S404a (step S404a: No), it returns to step S408a. If the control device 34 makes a positive determination in step S404a (step S404a: Yes), it proceeds to step S406a. In step S406a, the control device 34 terminates the engine starting process. Next, the control device 34 ends this process.

[0080] If the control device 34 makes a negative determination in step S408a (step S408a: No), it proceeds to step S404b. In step S404b, the control device 34 determines whether the engine speed is above the autonomous speed. If the control device 34 makes a negative determination in step S404b (step S404b: No), it repeats step S404b. If the control device 34 makes a positive determination in step S404b (step S404b: Yes), it proceeds to step S406b. In step S406b, the control device 34 terminates the engine starting process. Next, the control device 34 proceeds to step S410a. In step S410a, the control device 34 performs stop position control. Next, the control device 34 terminates this process.

[0081] Reference Figure 6 This explains the function of turning off the ignition switch 35 during the engine start-up process after a rapid idle shutdown.

[0082] First, with the vehicle 100 in a stopped state, the ignition switch 35 switches from off to on. During the period when the rapid idle shutdown condition is met (step S400: No), the engine speed is maintained at 0.

[0083] If the rapid idle shutdown condition is no longer met (step S400: Yes), the engine starting process begins (step S402). Therefore, the engine speed increases from 0.

[0084] Even when the ignition switch 35 is off (step S404a: No, step S408a: No), the engine starting process continues until the engine speed reaches the autonomous speed (step S404b: No). That is, the control device 34 performs the above-mentioned speed increase process during the repetition of step S404b.

[0085] After the engine speed reaches the autonomous speed (step S404b: Yes), the control device 34 terminates the engine starting process in step S406b. Next, the control device 34 performs the aforementioned stop position control in step S410a.

[0086] In the above embodiment, the rise process is performed with the ignition switch 35 off before the engine 10 rises to its autonomous speed after the start of the engine start process that raises the engine speed from 0. However, this is merely an example. The engine start process can be a process that raises the engine speed from a value greater than 0 to its autonomous speed. This will be explained next. When the stop condition specified above is met while the ignition switch 35 is on, the control device 34 automatically stops the engine 10. However, the situation where the automatic stop is interrupted can be considered. That is, the situation where a drive requirement for the engine 10 is generated before the engine 10 reaches a stop can be considered. In other words, the situation where the engine speed rises towards its autonomous speed from a state where the engine speed is decreasing towards 0 can be considered. In such a situation where the engine speed is lower than the autonomous speed, the ignition switch 35 can be turned off. In the above case, the rise process can be performed. Stop position control can be performed after the rise process is completed.

[0087] In the above embodiments, the control device 34 includes a CPU, ROM, and RAM, and performs software processing. However, this is merely an example. For example, the control device 34 may include dedicated hardware circuitry (e.g., an ASIC) for processing at least a portion of the software processing performed in the above embodiments. That is, the control device 34 can be any of the following structures (a) to (c): (a) The control device 34 includes a processing device that executes all processing according to a program and a program storage device such as a ROM that stores the program. That is, the control device 34 includes a software execution device. (b) The control device 34 includes a processing device that executes a portion of the processing according to a program and a program storage device. In addition, the control device 34 includes dedicated hardware circuitry for executing the remaining processing. (c) The control device 34 includes dedicated hardware circuitry for executing all processing. Here, there may be multiple software execution devices and / or dedicated hardware circuitry. That is, the above processing can be executed by a processing circuitry that includes at least one of the software execution device and dedicated hardware circuitry. The processing circuitry may include multiple software execution devices and dedicated hardware circuitry. A program storage device, or computer-readable medium, includes all available media that can be accessed by a general-purpose or special-purpose computer.

Claims

1. A control device of a vehicle that is provided with an engine having a cylinder and a motor generator that is linked to the engine, wherein the control device of the vehicle is provided with a processing circuit, the processing circuit is configured to, in a case where an ignition switch is turned off before an engine speed rises to a self-sustaining speed at which the engine is able to self-sustain, execute an increase process and, after the increase process is completed, execute a stop position control in correspondence with a case where the engine speed reaches the self-sustaining speed, the increase process is a process of causing the engine speed to increase up to the self-sustaining speed or more, the stop position control is a control of regenerative braking by which rotational energy of a crankshaft of the engine is converted into electric power by the motor generator, thereby causing a piston in the cylinder to stop at a prescribed position.

2. The control device of the vehicle according to claim 1, wherein the increase process includes cranking of the crankshaft of the engine and execution of combustion in the cylinder by the motor generator until the engine speed becomes the self-sustaining speed or more.

3. The control device of the vehicle according to claim 1 or 2, wherein the processing circuit is configured to, in a case where a fast idle cutoff condition is established, the fast idle cutoff condition including a case where the vehicle is stopped from a time point at which the ignition switch is turned on, execute a fast idle cutoff process that is a process of maintaining the engine speed at 0 from the time point at which the ignition switch is turned on, the processing circuit is configured to, in a case where the fast idle cutoff condition is no longer established, start an engine start process of causing the engine speed to increase from 0 by cranking of the crankshaft of the engine by the motor generator, the processing circuit is configured to, in a case where the ignition switch is turned off before the engine speed rises to the self-sustaining speed, execute the increase process of causing the engine speed to increase by cranking of the crankshaft of the engine by the motor generator, and, after the increase process is completed, execute the stop position control of causing the piston in the cylinder to stop at the prescribed position.

4. The control device of the vehicle according to claim 3, wherein the processing circuit is configured to, in a case where the stop position control fails to cause the piston to stop at the prescribed position, prohibit the fast idle cutoff process.

5. A control method of a vehicle that is provided with an engine having a cylinder and a motor generator that is linked to the engine, wherein the control method of the vehicle includes the following steps: in a case where an ignition switch is turned off before an engine speed rises to a self-sustaining speed at which the engine is able to self-sustain, an increase process is executed and, after the increase process is completed, a stop position control is executed in correspondence with a case where the engine speed reaches the self-sustaining speed, the increase process is a process of causing the engine speed to increase up to the self-sustaining speed or more, the stop position control is a control of regenerative braking by which rotational energy of a crankshaft of the engine is converted into electric power by the motor generator, thereby causing a piston in the cylinder to stop at a prescribed position. ​ The stop position control is control for stopping a piston in a cylinder at a prescribed position by regenerative braking in which the electric motor converts the rotational energy of a crankshaft of the engine into electric power. The stop position control is control for stopping a piston in a cylinder at a prescribed position by regenerative braking in which the electric motor converts the rotational energy of a crankshaft of the engine into electric power.

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