JP2020192902A - Hybrid vehicle - Google Patents

Abstract

To provide a hybrid vehicle capable of hastening an engine torque rise while suppressing a starting shock at engine starting in a situation in which sudden acceleration is required.SOLUTION: A vehicle control device is constituted to be capable of executing first starting control (S21-S24) in which an engine is cranked by a first electric motor (MG1), in which in-cylinder fuel injection is executed at a compression stroke in a cylinder (object cylinder) stopped at the compression stroke during the previous engine shutdown period, in which an initial explosion is caused by executing ignition after the in-cylinder fuel injection, and in which ignition retard is executed while a traveling drive force is assisted by a second electric motor (MG2).SELECTED DRAWING: Figure 10

Description

The present disclosure relates to a hybrid vehicle, and more particularly to engine start control in a hybrid vehicle.

Japanese Patent Application Laid-Open No. 2013-11248 (Patent Document 1) discloses a control device for intermittently operating an engine mounted on a hybrid vehicle. In intermittent operation, the control device temporarily stops the engine and then restarts it.

Japanese Unexamined Patent Publication No. 2013-11248

By the way, when the engine is started in a situation where sudden acceleration of the vehicle is required (for example, a situation where the accelerator pedal is greatly depressed by the driver), it is required to accelerate the rise of the engine torque. However, it is not easy to accelerate the rise of engine torque when starting the engine. For example, when the engine torque rises faster, an impact on the vehicle body (hereinafter, referred to as "starting shock") due to engine starting is likely to occur. Further, in an engine equipped with a turbocharger, the rise of engine torque may be delayed due to a response delay of the turbocharger (generally also referred to as "turbo lag").

In the engine start control described in Patent Document 1, an ignition retard angle (that is, a control for delaying the ignition timing) is executed in order to suppress knocking. It is considered that the starting shock is alleviated by the ignition retardation, but the rise of the engine torque is delayed.

The present disclosure has been made to solve the above problems, and an object thereof is to accelerate the rise of engine torque while suppressing a start shock when starting an engine in a situation where sudden acceleration is required. It is to provide a hybrid vehicle.

The hybrid vehicle according to the present disclosure includes an engine that generates a traveling driving force, a first electric motor that can crank the engine, a second electric motor that generates a traveling driving force, and a control device. The control device is configured to control the engine, the first electric motor, and the second electric motor. The engine includes at least one cylinder, intake and exhaust passages connected to all cylinders, and a supercharger. The cylinder includes a fuel injection valve for injecting fuel in the cylinder and an ignition device for ignition. The supercharger includes a compressor provided in the intake passage and a turbine provided in the exhaust passage. The control device is the first to crank the engine by the first electric motor, execute in-cylinder fuel injection in the compression stroke to the cylinder that stopped in the compression stroke when the engine was stopped last time, and ignite after the in-cylinder fuel injection. It is configured to be able to execute the first start control that executes the ignition retard angle while detonating and assisting the traveling driving force by the second electric motor.

In the first start control, the in-cylinder fuel injection is executed in the compression stroke to the cylinder stopped in the compression stroke, so that the engine can be detonated at an early stage. In addition, the earlier the initial explosion of the engine causes the exhaust temperature (and thus the flow velocity of the exhaust) to rise earlier. Then, as the exhaust flow rate and the exhaust flow velocity increase, the rotation speed of the turbine of the turbocharger increases, so that the engine torque rises faster.

When the control device injects fuel and ignites the cylinder stopped in the compression stroke and the cylinder first explodes without passing through the intake stroke, the starting shock tends to be large. Therefore, in the first start control, the control device suppresses the start shock by executing the ignition retard. Further, during the period in which the ignition retard angle is continued, the exhaust temperature becomes high and the rotation speed of the turbocharger turbine tends to increase.

When the ignition retard is executed, the torque generated by the combustion in the cylinder becomes smaller. Therefore, the engine torque becomes small due to the ignition retardation, and there is a possibility that a sufficient running driving force cannot be obtained. Therefore, in the first start control, the traveling driving force is assisted by the second electric motor during the period in which the ignition retard angle is continued. Therefore, the running driving force that is insufficient due to the ignition retard angle can be supplemented by the second electric motor. As a result, it is possible to secure a sufficient running driving force even during the period in which the ignition retard angle is continued after the initial explosion of the engine.

According to the above-mentioned first start control, when the engine is started, it is possible to accelerate the rise of the engine torque while suppressing the start shock. Since the above hybrid vehicle is equipped with a control device configured to be able to execute such a first start control, a start shock is caused by executing the first start control when the engine is started in a situation where sudden acceleration is required. It is possible to accelerate the rise of engine torque while suppressing it.

The in-cylinder fuel injection for the first explosion in the first start control may be performed immediately before cranking, immediately after cranking, or at the same time as cranking. The ignition for the first explosion in the first start control may be performed in the expansion stroke. "Last stop" means the most recent stop. The ignition retardation is a process of retarding the ignition timing with respect to the ignition timing in normal ignition control (for example, MBT (Minimum advance for the Best Torque) control).

The above control device cranks the engine by the first electric motor, and when the rotation speed of the engine exceeds a predetermined speed, executes the second start control that injects fuel and ignites one of the cylinders for the first explosion. It may be configured to be possible. The control device is first started when transitioning from EV travel (ie, travel performed by the second motor with the engine stopped) to HV travel (ie, travel performed by the engine and the second motor). It may be configured to select and execute either control or second start control.

At the time of transition from EV driving to HV driving (hereinafter, also simply referred to as “HV transition”), a starting shock is more likely to occur than when the engine is started while the vehicle is stopped. In the second start control, the engine is first detonated at a timing when the engine speed becomes higher than that in the first start control, so that a start shock is less likely to occur as compared with the first start control. In the above control device, the rise of the engine torque can be accelerated by the above-mentioned first start control at the time of HV transition, and the start shock can be made less likely to occur by the second start control at the time of HV transition. By selecting and executing either the first start control or the second start control at the time of HV transition, the above-mentioned control device can start the engine in a mode suitable for the situation at the time of engine start.

The fuel injection for the initial explosion in the second start control may be performed in the intake stroke or the compression stroke. The fuel injection in the second start control may be in-cylinder injection by the above-mentioned fuel injection valve (that is, a fuel injection valve for in-cylinder injection). Further, in a vehicle in which the cylinder further includes a fuel injection valve for injecting fuel into the intake port (that is, a fuel injection valve for port injection), the fuel injection in the second start control may be the intake port injection.

By executing the first start control in a situation where sudden acceleration of the vehicle is required, the vehicle can be rapidly accelerated in response to the request for sudden acceleration. More specifically, the above-mentioned control device may be configured to execute the first start control when the following requirements are satisfied at the time of HV transition.

The vehicle may further include an accelerator sensor that detects the amount of acceleration requested by the user (eg, the amount of depression of the accelerator pedal). The above-mentioned control device selects the first start control when the required acceleration amount is equal to or more than the threshold value (hereinafter, also referred to as "requirement (A)") when shifting from EV driving to HV driving. It may be configured.

The above control device selects the first start control when the power output to the engine when shifting from EV driving to HV driving satisfies the threshold value or more (hereinafter, also referred to as "requirement (B)"). It may be configured as follows.

The control device may be configured to perform HV driving in a plurality of driving modes including a power mode in which the engine is operated by giving priority to output power over fuel consumption. The control device selects the first start control when the driving mode of the vehicle is set to the power mode (hereinafter, also referred to as "requirement (C)") when shifting from EV driving to HV driving. It may be configured in.

Any one of the above requirements (A) to (C) may be adopted, or two requirements selected from the requirements (A) to (C) may be adopted, or the requirements (A) to (A) to (C) may be adopted. All of (C) may be adopted. In addition, adopting all of the requirements (A) to (C) means that the above control device selects the first start control when at least one of the requirements (A) to (C) is satisfied at the time of HV transition. It means that.

The above control device may be configured to control the travel of the vehicle in a preset travel mode. The control device includes a storage device that stores information indicating a driving mode (hereinafter, also referred to as "mode information"), and may be configured to specify the driving mode of the vehicle by referring to the mode information in the storage device. Good. The vehicle may further include an input device that accepts user input. The input device may be configured to set the driving mode input by the user among the plurality of driving modes in the control device.

The engine may include a plurality of the cylinders (that is, cylinders including the fuel injection valve and the ignition device), and may further include a crankshaft common to the plurality of cylinders. The control device may be configured to be able to detect the rotational position of the crankshaft and may be configured to store the rotational position of the crankshaft when the engine is stopped. Even if the above-mentioned control device is configured to identify a cylinder stopped in the compression stroke among a plurality of cylinders by using the rotation position of the crankshaft stored at the time of the previous stop of the engine in the first start control. Good.

According to the above control device, in an engine including a plurality of cylinders, it is possible to accurately identify the cylinders stopped in the compression stroke.

The above-mentioned control device may be configured to end the ignition retard angle when a predetermined end condition is satisfied after starting the ignition retard angle.

According to the above configuration, by setting an appropriate termination condition in the control device by experiment or simulation in advance, the ignition retard angle can be set at an appropriate timing (for example, the timing when the turbine rotation speed of the turbocharger sufficiently increases). It is possible to exit and return to normal ignition control (eg MBT control).

Each of the engine and the first electric motor may be mechanically connected to the drive wheels of the hybrid vehicle via planetary gears. The planetary gear and the second electric motor may be configured so that the power output from the planetary gear and the power output from the second electric motor are combined and transmitted to the drive wheels.

According to the above configuration, the above-mentioned cranking and the assistance of the traveling driving force can be appropriately performed by the first electric motor and the second electric motor.

According to the present disclosure, it is possible to provide a hybrid vehicle capable of accelerating the rise of engine torque while suppressing a start shock when the engine is started in a situation where sudden acceleration is required.

It is a figure which shows the drive device of the vehicle which concerns on embodiment of this disclosure. It is a figure which shows the engine of the vehicle which concerns on embodiment of this disclosure. It is a figure which shows the structure of each cylinder included in the engine body shown in FIG. It is a figure which shows one combustion cycle of each cylinder included in the engine body shown in FIG. It is a block diagram which shows the control system of the vehicle which concerns on embodiment of this disclosure. It is a collinear diagram which shows an example of the relationship of the rotational speed of each rotating element (sun gear, a carrier, ring gear) of a planetary gear during HV running in the vehicle which concerns on embodiment of this disclosure. It is a collinear diagram which shows an example of the relationship of the rotational speed of each rotating element (sun gear, carrier, ring gear) of a planetary gear during EV traveling in the vehicle which concerns on embodiment of this disclosure. FIG. 5 is a collinear diagram showing an example of the relationship between the rotational speeds of each rotating element (sun gear, carrier, ring gear) of the planetary gear while the vehicle is stopped in the vehicle according to the embodiment of the present disclosure. It is a figure which shows the detail of each structure of the control device and the mechanism for detecting a crank angle about the vehicle which concerns on embodiment of this disclosure. It is a flowchart which shows the processing procedure of the engine start control executed by the control device of the vehicle which concerns on embodiment of this disclosure. It is a figure for demonstrating the operation of the hybrid vehicle which concerns on embodiment of this disclosure. FIG. 5 is a collinear diagram showing an example of the relationship between the rotational speeds of each rotating element (sun gear, carrier, ring gear) of the planetary gear during cranking in the vehicle according to the embodiment of the present disclosure.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the figure, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated. Hereinafter, the electronic control unit is also referred to as an "ECU". Further, the hybrid vehicle is also referred to as "HV", and the electric vehicle is also referred to as "EV".

FIG. 1 is a diagram showing a vehicle drive device according to this embodiment. In this embodiment, a front-wheel drive four-wheel vehicle (more specifically, a hybrid vehicle) is assumed, but the number of wheels and the drive system can be changed as appropriate. For example, the drive system may be four-wheel drive.

With reference to FIG. 1, the vehicle drive device 10 includes an engine 13 and MGs (Motor Generators) 14 and 15 as power sources for traveling. Each of the MGs 14 and 15 is a motor generator that has both a function as a motor that outputs torque when driving power is supplied and a function as a generator that generates generated power when torque is applied. .. As each of MG 14 and 15, an AC motor (for example, a permanent magnet type synchronous motor or an induction motor) is used. The MG 14 is electrically connected to the battery 18 via an electric circuit including the first inverter 16. The MG 15 is electrically connected to the battery 18 via an electric circuit including a second inverter 17. The first inverter 16 and the second inverter 17 are included in the PCU 19 (see FIG. 5) described later. The MGs 14 and 15 have rotor shafts 23 and 30, respectively. The rotor shafts 23 and 30 correspond to the rotation shafts of MG 14 and 15, respectively. MG14 and MG15 according to this embodiment correspond to examples of "first electric motor (MG1)" and "second electric motor (MG2)" according to the present disclosure, respectively.

The battery 18 includes, for example, a secondary battery. As the secondary battery, for example, a lithium ion battery can be adopted. The battery 18 may include an assembled battery composed of a plurality of electrically connected secondary batteries (for example, a lithium ion battery). The secondary battery constituting the battery 18 is not limited to the lithium ion battery, and may be another secondary battery (for example, a nickel hydrogen battery). As the battery 18, an electrolytic solution type secondary battery may be adopted, or an all-solid-state type secondary battery may be adopted. As the battery 18, any power storage device can be adopted, and a large-capacity capacitor or the like can also be adopted.

The drive device 10 includes a planetary gear mechanism 20. The engine 13 and MG 14 are connected to the planetary gear mechanism 20. The MG 14 can forcibly rotate the output shaft 22 of the engine 13. The output shaft 22 of the engine 13 is connected to the crankshaft 131 shown in FIG. 3, which will be described later, and the crankshaft 131 also rotates as the output shaft 22 rotates. In this way, the MG 14 is configured to be able to crank the engine 13 (see FIG. 12 described later for details). The planetary gear mechanism 20 is a single pinion type planetary gear, and is arranged on the same axis Cnt as the output shaft 22 of the engine 13.

The planetary gear mechanism 20 has a sun gear S, a ring gear R arranged coaxially with the sun gear S, a pinion gear P that meshes with the sun gear S and the ring gear R, and a carrier C that holds the pinion gear P so that it can rotate and revolve. Each of the engine 13 and MG 14 is mechanically connected to the drive wheels 24 via the planetary gear mechanism 20. The output shaft 22 of the engine 13 is connected to the carrier C. The rotor shaft 23 of the MG 14 is connected to the sun gear S. The ring gear R is connected to the output gear 21.

The planetary gear mechanism 20 has three rotating elements, namely an input element, an output element, and a reaction force element. In the planetary gear mechanism 20, the carrier C is an input element, the ring gear R is an output element, and the sun gear S is a reaction force element. The torque output by the engine 13 is input to the carrier C. The planetary gear mechanism 20 is configured to divide and transmit the torque output by the engine 13 to the output shaft 22 into the sun gear S (and thus the MG 14) and the ring gear R (and thus the output gear 21). The ring gear R outputs torque to the output gear 21, and the reaction torque due to the MG 14 acts on the sun gear S. The power output from the planetary gear mechanism 20 (planetary gear) (that is, the power output to the output gear 21) is the driven gear 26, the counter shaft 25, the drive gear 27, the differential gear 28, and the drive shaft 32, which will be described below. It is transmitted to the drive wheels 24 via 33.

The drive device 10 further includes a counter shaft 25, a driven gear 26, a drive gear 27, a differential gear 28, a drive gear 31, and drive shafts 32 and 33. The differential gear 28 corresponds to a final speed reducer and includes a ring gear 29.

The planetary gear mechanism 20 and the MG 15 are configured such that the power output from the planetary gear mechanism 20 and the power output from the MG 15 are combined and transmitted to the drive wheels 24. Specifically, the output gear 21 connected to the ring gear R of the planetary gear mechanism 20 meshes with the driven gear 26. Further, the drive gear 31 attached to the rotor shaft 30 of the MG 15 also meshes with the driven gear 26. The counter shaft 25 is attached to the driven gear 26 and is arranged parallel to the axis Cnt. The drive gear 27 is attached to the counter shaft 25 and meshes with the ring gear 29 of the differential gear 28. The driven gear 26 acts so as to combine the torque output by the MG 15 to the rotor shaft 30 and the torque output from the ring gear R to the output gear 21. The drive torque thus combined is transmitted to the drive wheels 24 via the drive shafts 32 and 33 extending from the differential gear 28 to the left and right.

The drive device 10 further includes a mechanical oil pump 36 and an electric oil pump 38. The oil pump 36 is provided coaxially with the output shaft 22. The oil pump 36 is driven by the engine 13. The oil pump 36 sends lubricating oil to the planetary gear mechanism 20, MG14, MG15, and the differential gear 28 when the engine 13 is operating. The electric oil pump 38 is driven by electric power supplied from the battery 18 or another vehicle-mounted battery (for example, an auxiliary battery) (not shown), and is controlled by an HVECU 62 (see FIG. 5) described later. The electric oil pump 38 sends lubricating oil to the planetary gear mechanism 20, MG14, MG15, and the differential gear 28 when the engine 13 is stopped. The lubricating oil sent by each of the oil pump 36 and the electric oil pump 38 has a cooling function.

FIG. 2 is a diagram showing the configuration of the engine 13. With reference to FIG. 2, the engine 13 is, for example, an in-line 4-cylinder spark-ignition internal combustion engine. The engine 13 includes an engine body 13a including four cylinders 40a, 40b, 40c, 40d, and an intake passage 41 and an exhaust passage 42 connected to all cylinders (that is, cylinders 40a, 40b, 40c, 40d). .. In the engine body 13a, four cylinders 40a, 40b, 40c, and 40d are arranged in one direction. Hereinafter, each of the cylinders 40a, 40b, 40c, and 40d will be referred to as "cylinder 40" except for the case where they will be described separately.

FIG. 3 is a diagram showing a configuration of each cylinder 40 included in the engine body 13a. With reference to FIG. 2 and FIG. 3, the intake port 43 and the exhaust port 44 of the cylinder 40 are connected to the intake passage 41 and the exhaust passage 42, respectively. The cylinder 40 includes a combustion chamber 401, a piston 402, a connecting rod 403, an intake valve 431, an intake camshaft 432, an intake cam 433, an exhaust valve 441, an exhaust camshaft 442, and an exhaust cam 443. It includes an ignition device 45 and an injector 46. The ignition device 45 includes a spark plug and a booster circuit (not shown), and is configured to ignite the air-fuel mixture in the combustion chamber 401. The injector 46 is configured to inject in-cylinder fuel into the cylinder 40 (that is, directly inject fuel into the cylinder 40). Further, the engine 13 includes a cam angle sensor 130, a crankshaft 131 common to the cylinders 40a, 40b, 40c, and 40d, a crank angle sensor 132, and an engine cooling water temperature sensor 70.

The intake port 43 is opened and closed by the intake valve 431, and the exhaust port 44 is opened and closed by the exhaust valve 441. A mixture of air and fuel is generated by adding fuel (for example, gasoline) to the air supplied into the cylinder 40 through the intake port 43. The fuel is injected into the cylinder 40 by the injector 46, and an air-fuel mixture is generated in the cylinder 40. Then, a voltage is applied to the spark plug of the ignition device 45, and the air-fuel mixture is ignited in the cylinder 40. As a result, combustion and explosion occur in the combustion chamber 401, and the high-temperature and high-pressure combustion gas expands and pushes down the piston 402. The power of the piston 402 generated in this way is transmitted to the crankshaft 131 via the connecting rod 403. The power generated by the cylinders 40a to 40d of the engine 13 is output to the crankshaft 131 common to the cylinders 40a to 40d.

When the intake camshaft 432 common to the four cylinders 40 rotates, the intake cam 433 of each cylinder 40 also rotates, and the intake valve 431 is opened and closed by the intake cam 433. When the exhaust camshaft 442 common to the four cylinders 40 rotates, the exhaust cam 443 of each cylinder 40 also rotates, and the exhaust valve 441 is opened and closed by the exhaust cam 443. The intake camshaft 432, the exhaust camshaft 442, and the crankshaft 131 are configured to rotate synchronously, for example, by being connected by a timing chain.

When the engine 13 is operating, the piston 402 reciprocates in each cylinder 40 of the engine body 13a, and in each cylinder 40, four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke (hereinafter, "" (Also referred to as "1 combustion cycle") is repeated. In the intake stroke, the piston 402 is lowered, the intake valve 431 is opened, and air is sucked into the cylinder 40 from the intake port 43. In the compression stroke, the piston 402 rises to compress the air in the cylinder 40. In the expansion stroke, combustion and explosion occur in the combustion chamber 401, and the combustion gas pushes down the piston 402. In the exhaust stroke, the piston 402 rises, the exhaust valve 441 opens, and the combustion gas in the cylinder 40 is discharged from the exhaust port 44. Each of the intake camshaft 432 and the exhaust camshaft 442 is configured to rotate at half the rotational speed of the crankshaft 131. Each of the intake camshaft 432 and the exhaust camshaft 442 makes one rotation (360 ° rotation) per combustion cycle, so that the intake valve 431 opens in the intake stroke and the exhaust valve 441 opens in the exhaust stroke. The crankshaft 131 makes two rotations (720 ° rotation) per combustion cycle.

FIG. 4 is a diagram showing one combustion cycle of cylinders 40a, 40b, 40c, and 40d. In FIG. 4, “° CA” indicates the crank angle (that is, the rotational position of the crankshaft 131). “# 1”, “# 2”, “# 3”, and “# 4” represent cylinders 40a, 40b, 40c, and 40d, respectively.

As shown in FIG. 4, the cylinders 40a, 40b, 40c, and 40d operate with a shift of one stroke (180 ° CA). Therefore, when the engine 13 is stopped (and by extension, when the rotation of the crankshaft 131 is stopped), there is one cylinder 40 that stops in the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke.

With reference to FIG. 2 again, the engine 13 includes a turbocharged turbocharger 47 that supercharges intake air using exhaust energy. The supercharger 47 is a turbocharger including a compressor 48, a turbine 53, and a shaft 53a. The compressor 48 and the turbine 53 are connected to each other via a shaft 53a and are configured to rotate integrally. The rotational force of the turbine 53, which rotates in response to the flow of exhaust gas discharged from the engine body 13a, is transmitted to the compressor 48 via the shaft 53a. As the compressor 48 rotates, the intake air toward the engine body 13a is compressed, and the compressed air is supplied to the engine body 13a. The supercharger 47 is configured to supercharge the intake air by rotating the turbine 53 and the compressor 48 using the exhaust energy.

The compressor 48 is arranged in the intake passage 41. An air flow meter 50 is provided at a position upstream of the compressor 48 in the intake passage 41. The air flow meter 50 is configured to output a signal according to the flow rate of air flowing in the intake passage 41. An intercooler 51 is provided at a position downstream of the compressor 48 in the intake passage 41. The intercooler 51 is configured to cool the intake air compressed by the compressor 48. A throttle valve 49 (intake throttle valve) is provided at a position downstream of the intercooler 51 in the intake passage 41. The throttle valve 49 is configured so that the flow rate of the intake air flowing in the intake passage 41 can be adjusted. The opening degree of the throttle valve 49 is controlled by the HVECU 62 (see FIG. 5) described later. The air flowing into the intake passage 41 is supplied to each cylinder 40 of the engine body 13a through the air flow meter 50, the compressor 48, the intercooler 51, and the throttle valve 49 in this order.

The turbine 53 is arranged in the exhaust passage 42. Further, the exhaust passage 42 is provided with a WGV (wastegate valve) mechanism 54. The WGV mechanism 54 is configured so that the exhaust gas upstream of the turbine 53 can be bypassed downstream of the turbine 53. The WGV mechanism 54 includes a WGV (wastegate valve) 55 capable of adjusting the flow rate of the exhaust gas guided to the turbine 53. The exhaust flow rate (and thus the boost pressure) flowing into the turbine 53 changes depending on the opening degree of the WGV 55. As the WGV 55 closes (that is, approaches the fully closed state), the exhaust flow rate flowing into the turbine 53 increases, and the pressure of the intake air (that is, the boost pressure) increases. The exhaust gas discharged from the engine body 13a passes through either the turbine 53 or the WGV 55, and is released to the atmosphere after the harmful substances are removed by the start catalyst converter 56 and the aftertreatment device 57. The aftertreatment device 57 includes, for example, a three-way catalyst.

The engine 13 is provided with an EGR (Exhaust Gas Recirculation) device 58 that allows exhaust gas to flow into the intake passage 41. The EGR device 58 includes an EGR passage 59, an EGR valve 60, and an EGR cooler 61. The EGR passage 59 is configured to take out a part of the exhaust gas from the exhaust passage 42 as EGR gas and guide it to the intake passage 41. The EGR passage 59 is provided with an EGR valve 60 and an EGR cooler 61. The EGR valve 60 is configured so that the flow rate of the EGR gas flowing through the EGR passage 59 can be adjusted. The EGR cooler 61 is configured to cool the EGR gas flowing through the EGR passage 59.

FIG. 5 is a block diagram showing a vehicle control system according to this embodiment. With reference to FIG. 5 with FIGS. 1 and 2, the vehicle control system includes an HVECU 62, an MGECU 63, and an engine ECU 64. The HVECU 62 includes an accelerator sensor 66, a vehicle speed sensor 67, an MG1 rotation speed sensor 68, an MG2 rotation speed sensor 69, an engine cooling water temperature sensor 70, a turbine rotation speed sensor 71, a boost pressure sensor 72, an SOC sensor 73, and an MG1 temperature sensor 74. , MG2 temperature sensor 75, INV1 temperature sensor 76, INV2 temperature sensor 77, catalyst temperature sensor 78, and supercharger temperature sensor 79 are connected.

The accelerator sensor 66 outputs a signal to the HVECU 62 according to the amount of accelerator operation (for example, the amount of depression of the accelerator pedal (not shown)). The accelerator operation amount is a parameter indicating the acceleration amount required by the driver for the vehicle (hereinafter, also referred to as "required acceleration amount"). The larger the accelerator operation amount, the larger the driver's required acceleration amount. The vehicle speed sensor 67 outputs a signal corresponding to the vehicle speed (that is, the traveling speed of the vehicle) to the HVECU 62. The MG1 rotation speed sensor 68 outputs a signal corresponding to the rotation speed of the MG 14 to the HVECU 62. The MG2 rotation speed sensor 69 outputs a signal corresponding to the rotation speed of the MG 15 to the HVECU 62. The engine cooling water temperature sensor 70 outputs a signal to the HVECU 62 according to the temperature of the cooling water flowing through the water jacket formed in the cylinder block of the engine body 13a. The turbine rotation speed sensor 71 outputs a signal corresponding to the rotation speed of the turbine 53 of the turbocharger 47 to the HVECU 62. The boost pressure sensor 72 outputs a signal corresponding to the boost pressure of the engine 13 to the HVECU 62.

The SOC sensor 73 outputs a signal to the HVECU 62 according to the SOC (State of Charge), which is the ratio of the remaining charge amount to the full charge amount (that is, the storage capacity) of the battery 18. The MG1 temperature sensor 74 outputs a signal corresponding to the temperature of the MG 14 to the HVECU 62. The MG2 temperature sensor 75 outputs a signal corresponding to the temperature of the MG 15 to the HVECU 62. The INV1 temperature sensor 76 outputs a signal corresponding to the temperature of the first inverter 16 to the HVECU 62. The INV2 temperature sensor 77 outputs a signal corresponding to the temperature of the second inverter 17 to the HVECU 62. The catalyst temperature sensor 78 outputs a signal corresponding to the temperature of the aftertreatment device 57 to the HVECU 62. The supercharger temperature sensor 79 outputs a signal to the HVECU 62 according to the temperature of a predetermined portion of the supercharger 47 (for example, the temperature of the turbine 53).

The HVECU 62 includes a processor 62a, a RAM (Random Access Memory) 62b, a storage device 62c, and an input / output port and a timer (not shown). As the processor 62a, for example, a CPU (Central Processing Unit) can be adopted. The RAM 62b functions as a working memory for temporarily storing data processed by the processor 62a. The storage device 62c is configured to be able to store the stored information. The storage device 62c includes, for example, a ROM (Read Only Memory) and a rewritable non-volatile memory. In addition to the program, the storage device 62c stores information used in the program (for example, maps, mathematical formulas, and various parameters). When the processor 62a executes the program stored in the storage device 62c, various controls of the vehicle are executed. Other ECUs (for example, MGECU 63 and engine ECU 64) also have the same hardware configuration as the HVECU 62. In this embodiment, the HVECU 62, the MGECU 63, and the engine ECU 64 are separated, but one ECU may have these functions.

The HVECU 62 is configured to output a command for controlling the engine 13 (for example, an engine operating state command) to the engine ECU 64. The engine ECU 64 is configured to control the throttle valve 49, the ignition device 45, the injector 46, the WGV55, and the EGR valve 60 in accordance with a command from the HVECU 62. The HVECU 62 can control the engine through the engine ECU 64. For example, the HVECU 62 requests the engine ECU 64 to increase the boost pressure when the engine torque exceeds a predetermined value. The engine ECU 64 increases the boost pressure by closing the WGV 55 in accordance with the request from the HVE ECU 62.

The HVECU 62 is configured to output commands (for example, a first MG torque command and a second MG torque command) for controlling each of the MG 14 and the MG 15 to the MG ECU 63. The vehicle is further equipped with a PCU (Power Control Unit) 19. The MG ECU 63 is configured to control the MG 14 and MG 15 through the PCU 19. The MG ECU 63 generates a current signal (for example, a signal indicating the magnitude and frequency of the current) corresponding to each target torque of the MG 14 and MG 15 according to a command from the HVE ECU 62, and outputs the generated current signal to the PCU 19. It is composed. The HVECU 62 can control the motor through the MGECU 63.

The PCU 19 includes a first inverter 16, a second inverter 17, and a converter 65. Each of MG14 and MG15 is electrically connected to PCU19. The first inverter 16 and the converter 65 are configured to perform power conversion between the battery 18 and the MG 14. The second inverter 17 and the converter 65 are configured to perform power conversion between the battery 18 and the MG 15. The PCU 19 is configured to supply the electric power stored in the battery 18 to each of the MG 14 and the MG 15, and to supply the electric power generated by each of the MG 14 and the MG 15 to the battery 18. The PCU 19 is configured so that the states of the MGs 14 and 15 can be controlled separately. For example, the MG14 can be put into a regenerative state (that is, a power generation state) while the MG15 is put into a power running state. The PCU 19 is configured to be able to supply the electric power generated by one of the MG 14 and the MG 15 to the other. The MG 14 and MG 15 are configured so that electric power can be exchanged with each other.

The vehicle is configured to perform HV driving and EV driving. The HV running is a running performed by the engine 13 and the MG 15 while generating a running driving force by the engine 13. The EV running is a running performed by the MG 15 with the engine 13 stopped. When the engine 13 is stopped, combustion in the engine body 13a is not performed. When the combustion in the engine body 13a is stopped, the combustion energy (and thus the traveling driving force of the vehicle) is not generated in the engine 13. The HVECU 62 is configured to switch between EV traveling and HV traveling according to the situation.

The HVECU 62 obtains the required driving force based on, for example, the accelerator opening degree and the vehicle speed, and cooperatively controls the engines 13, MG 14, and MG 15 so that the required driving force is output to the drive wheels 24. In HV driving, the torque obtained by adding the torque output by the engine 13 and the torque output by the MG 15 is the running driving force. In EV traveling, the torque output by MG 15 becomes the traveling driving force. The torque generated in the MG 15 is calculated so that the required driving force is output to the drive wheels 24.

The HVECU 62 is configured to control the operating point of the engine 13 to a target operating point. The operating point of the engine 13 is the operating state of the engine 13 defined by the engine torque and the engine rotation speed. The HVECU 62 obtains the required engine power based on the traveling mode and the required driving force, and determines the target operating point based on the required engine power. The HVECU 62, for example, sets the intersection of a line (equal power line) at which the engine power is equal to the required engine power and a recommended operating line (for example, the optimum fuel consumption line) on the coordinate plane of the engine speed and the engine torque. Set as the target operating point. The optimum fuel consumption line is a line connecting the operating points of the engine having the lowest fuel consumption on the coordinate plane of the engine rotation speed and the engine torque.

The planetary gear mechanism 20 shown in FIG. 1 can function as a continuously variable transmission mechanism. The planetary gear mechanism 20 is configured so that the ratio of the rotation speed of the input element (carrier C) to the rotation speed of the output element (ring gear R) can be continuously changed. The rotation speed of the engine 13 can be adjusted by the HVECU 62 controlling the rotation speed of the MG 14. The HVECU 62 can arbitrarily control the rotation speed of the MG 14 according to the magnitude and frequency of the current flowing through the MG 14.

FIG. 6 is a collinear diagram showing an example of the relationship between the rotation speeds of the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 20 during HV traveling. With reference to FIG. 6, in an example of HV traveling, when the torque output from the engine 13 (that is, the torque input to the carrier C) is transmitted to the drive wheels 24, the reaction force is transmitted by the MG 14 to the planetary gear mechanism 20. It acts on the sun gear S of. Therefore, the sun gear S functions as a reaction force element. In HV driving, the MG 14 is made to output a reaction force torque with respect to the target engine torque in order to apply a torque corresponding to the target engine torque based on the acceleration request to the drive wheels 24. This reaction torque can be used to cause the MG 14 to perform regenerative power generation.

FIG. 7 is a collinear diagram showing an example of the relationship between the rotation speeds of the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 20 during EV traveling. With reference to FIG. 7, in EV traveling, the engine 13 is stopped and the MG 15 generates a traveling driving force. During EV travel, the HVECU 62 controls the ignition device 45 and the injector 46 to prevent combustion in the engine 13. Since the EV traveling is performed in a state where the engine 13 is not rotating, the rotation speed of the carrier C becomes 0 as shown in FIG. 7.

FIG. 8 is a collinear diagram showing an example of the relationship between the rotation speeds of the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 20 while the vehicle is stopped. With reference to FIG. 8, the HVECU 62 controls the engine 13 and the MGs 14 and 15 to set the rotation speeds of the sun gear S, the carrier C, and the ring gear R to 0, whereby the vehicle stops running and the vehicle moves. It will be stopped.

By the way, when the engine is started in a situation where rapid acceleration of the vehicle is required, it is required to accelerate the rise of the engine torque. However, it is not easy to accelerate the rise of engine torque when starting the engine. For example, when the engine torque rises faster, a starting shock (that is, an impact on the vehicle body due to engine starting) is likely to occur. In addition, the rise of engine torque may be delayed due to the delay in response of the turbocharger.

Therefore, the vehicle according to this embodiment has the configuration described below, so that when the engine is started in a situation where rapid acceleration of the vehicle is required, the start-up of the engine torque is accelerated while suppressing the start shock. Is possible.

The HVECU 62 is configured to be capable of executing engine start control for sudden acceleration in addition to normal engine start control. As engine start control for sudden acceleration, the engine 13 is cranked by MG14, and in-cylinder fuel injection is executed in the compression stroke to the cylinders 40a to 40d that were stopped in the compression stroke when the engine 13 was stopped last time. The first start control is adopted, in which the engine is first detonated by igniting after the in-cylinder fuel injection, and the ignition retard is executed while assisting the traveling driving force by the MG15. As normal engine start control, the engine 13 is cranked by the MG 14, and when the rotation speed of the engine 13 exceeds a predetermined speed, fuel injection and ignition for the initial explosion are performed on any of the cylinders 40a to 40d. 2 Start control is adopted.

In this embodiment, the HVECU 62 is configured to select and execute either the first start control or the second start control when shifting from EV running to HV running (that is, at the time of HV transition). .. The HVECU 62 according to this embodiment corresponds to an example of the "control device" according to the present disclosure.

The timing of executing the selection of the engine start control is not limited to the time of HV transition. For example, the selection of the engine start control may be executed when the engine is started while the vehicle is stopped. For example, the HVECU 62 may be configured to be able to execute idling control that automatically stops the engine 13 when the idle stop condition is satisfied and automatically restarts the engine 13 when the idle stop condition is not satisfied. .. Then, the HVECU 62 may be configured to execute the selection of the engine start control (for example, the process of FIG. 10 described later) at the time of automatic restart in the idling control. The idle stop conditions are that the vehicle is stopped (that is, the vehicle speed is 0), the accelerator operation amount is 0, and the brake pedal (not shown) of the vehicle is depressed. It may be a condition that is satisfied when all are satisfied, and is not satisfied when any of these is not satisfied. The HVECU 62 may be configured to select and execute the first start control when the required acceleration amount is equal to or greater than the threshold value when starting the engine 13.

FIG. 9 is a diagram showing details of each configuration of the HVECU 62 and the mechanism for detecting the crank angle (that is, the rotational position of the crankshaft 131 shown in FIG. 3). First, a mechanism for detecting the crank angle will be described, and details of the configuration of the HVECU 62 will be described later.

A timing rotor 133 is attached to the crankshaft 131 with reference to FIG. 9 as well as FIG. A plurality of protrusions 133a are formed on the outer circumference of the timing rotor 133 at equal angles (for example, every 10 ° CA). Further, on the outer periphery of the timing rotor 133, a tooth missing portion 133b, which is a portion where the tooth (protruding portion 133a) is missing, is provided. The crank angle sensor 132 is arranged in the vicinity of the timing rotor 133. The crank angle sensor 132 is configured to be capable of detecting both forward and reverse rotation. As the crank angle sensor 132, for example, an electromagnetic pickup can be adopted. As the crankshaft 131 rotates, a crank signal (for example, a signal indicating an H (high) / L (low) level) corresponding to the unevenness of the timing rotor 133 is output from the crank angle sensor 132 to the HVECU 62. For example, when any of the protrusions 133a passes between the crankshaft 131 and the crank angle sensor 132, the crank signal becomes H level. Since the protrusions 133a are provided at equal angles, the crank signal becomes H level every time the crankshaft 131 rotates by a predetermined angle (for example, 10 ° CA). Since the tooth missing portion 133b is provided at one position on the outer periphery of the timing rotor 133, a long L level period (that is, an L level period corresponding to the tooth missing portion 133b) appears every time the rotation is 360 ° CA. The HVECU 62 is configured to calculate the rotational speed of the engine 13 using a crank signal.

A timing rotor 434 is attached to the intake camshaft 432. Three protrusions 434a, 434b, and 434c are formed on the outer circumference of the timing rotor 434. The cam angle sensor 130 is arranged in the vicinity of the timing rotor 434. As the cam angle sensor 130, for example, a sensor using a magnetoresistive element (MRE) can be adopted. As the intake camshaft 432 rotates, a cam signal (for example, a signal indicating the H (high) / L (low) level) corresponding to the unevenness of the timing rotor 434 is output from the cam angle sensor 130 to the HVECU 62. For example, when any of the protrusions 434a, 434b, and 434c passes between the intake camshaft 432 and the cam angle sensor 130, the cam signal becomes H level. Such a cam signal functions as a cylinder discrimination signal.

The HVECU 62 has a crank counter indicating a crank angle in the storage device 62c, and is configured to update the crank counter using a crank signal and a cam signal. The HVECU 62 can perform fuel injection and ignition at appropriate timings based on the crank counter.

The crank counter is a counter in which two rotations of the crankshaft 131 are set as one cycle. The reference (0 ° CA) of the crank counter can be arbitrarily set, but in this embodiment, as shown in FIG. 4, the compression top dead center (compression TDC) of the cylinder 40a (# 1) is used as a reference (0 ° CA). ) Is generated as a crank counter. Since the intake camshaft 432 and the crankshaft 131 rotate in synchronization, there is a certain correlation between the crank angle and the cam signal. Information indicating the correlation between the crank angle and the cam signal (hereinafter, also referred to as “crank position information”) is stored in the storage device 62c in advance. For example, the storage device 62c has a crank angle and cam signal (H level / L level) corresponding to the tooth missing portion 133b, when the cam signal is inverted (that is, when switching from H level to L level, and L. The crank angle (when switching from level to H level) is stored in advance. The HVECU 62 counts up the crank counter using the crank signal. The HVECU 62 counts up the crank counter according to a change in the crank angle accompanying the rotation of the crankshaft 131, while confirming the suitability of the value of the crank counter using the crank position information stored in the storage device 62c. Further, the HVECU 62 receives a cam edge signal from the cam angle sensor 130 each time the intake camshaft 432 makes one rotation. The cam edge signal is a signal output from the cam angle sensor 130 when the cam signal is inverted by, for example, the terminal portion of the protrusion 434b of the timing rotor 434. The HVECU 62 resets the crank counter each time it receives a cam edge signal. The crank counter counts up while the four cylinders 40a, 40b, 40c, and 40d, which are 180 ° CA out of phase with each other, operate one combustion cycle (see FIG. 4).

As described above, the HVECU 62 is configured to be able to detect the crank angle. Further, the HVECU 62 is configured to store the crank angle when the engine 13 is stopped. The HVECU 62 stores the crank angle in the storage device 62c when the rotation of the crankshaft 131 is stopped, and reads the stored crank angle from the storage device 62c when the engine 13 is restarted for use. The HVECU 62 can recognize the crank angle at the start of the engine 13 by using the crank angle stored at the time of the previous stop of the engine 13 (hereinafter, also referred to as “previous stop crank angle”).

When the engine 13 is started, the HVECU 62 starts counting up the crank counter with the previously stopped crank angle as the initial value of the crank counter. When the crankshaft 131 rotates due to cranking at the time of starting the engine and the crank angle sensor 132 detects the crank angle corresponding to the missing tooth portion 133b, the HVECU 62 stores the crank position information stored in the storage device 62c. Use to check the suitability of the crank counter value, and if the crank counter is out of alignment, correct the crank counter.

However, in the first start control, the in-cylinder fuel injection is performed substantially at the same time as the cranking (for example, immediately after the cranking). In the first start control, it is highly possible that fuel injection and ignition for the initial explosion are performed before the crank angle corresponding to the tooth missing portion 133b is detected. Therefore, in the first start control, the above-mentioned crank counter is not modified at the time of the first explosion, the cylinder 40 stopped in the compression stroke is specified by the previous stop crank angle, and the specified cylinder 40 is fuel-injected and ignited. Is done. Even if the ignition timing is deviated in the first start control, the reverse rotation of the crankshaft 131 is suppressed by cranking.

On the other hand, in the second start control, the rotation speed of the engine 13 is increased by cranking until it exceeds a predetermined speed (hereinafter, also referred to as "initial explosion speed"), and then fuel injection and ignition for the initial explosion are performed. .. In this embodiment, a speed high enough to sufficiently suppress the starting shock is set as the initial explosion speed. In the second start control, fuel injection and ignition for the first explosion are performed after the crank angle corresponding to the tooth missing portion 133b is detected. In the second start control, the above-mentioned crank counter is modified before the first explosion.

Next, the components of the HVECU 62 will be described by function. The HVECU 62 includes a traveling control unit 621, a sudden acceleration determination unit 622, a first start control unit 623, and a second start control unit 624. Each of the above parts in the HVECU 62 is embodied by, for example, the processor 62a shown in FIG. 5 and the program executed by the processor 62a. However, the present invention is not limited to this, and each of these parts may be embodied by dedicated hardware (electronic circuit).

The travel control unit 621 is configured to control the travel of the vehicle so that the required driving force is output to the drive wheels 24 shown in FIG. 1 while switching between EV travel and HV travel according to the situation. For example, the traveling control unit 621 performs EV traveling under low-speed and low-load traveling conditions, and performs HV traveling under high-speed and high-load traveling conditions. It is judged that the larger the required driving force, the larger the traveling load. The travel control unit 621 controls the travel of the vehicle by co-controlling the engines 13, MG14, and MG15.

The sudden acceleration determination unit 622 is configured to determine whether or not the sudden acceleration of the vehicle is required. In this embodiment, the sudden acceleration determination unit 622 makes the above determination when shifting from EV travel to HV travel. The sudden acceleration determination unit 622 determines whether or not the sudden acceleration of the vehicle is required, for example, based on the traveling mode of the vehicle described later.

The first start control unit 623 is configured to execute the first start control described above when the sudden acceleration determination unit 622 determines that the sudden acceleration of the vehicle is required. The second start control unit 624 is configured to execute the above-mentioned second start control when the sudden acceleration determination unit 622 determines that the sudden acceleration of the vehicle is not required. Details of the first start control and the second start control will be described later (see FIG. 10).

The vehicle further includes an input device 101 that receives input from the user. The input device 101 is operated by the user and outputs a signal corresponding to the user's operation to the HVECU 62. For example, the user can input a predetermined instruction or request to the HVECU 62 or set a parameter value to the HVECU 62 through the input device 101. The communication method may be wired or wireless. As the input device 101, for example, various switches (for example, push button switch or slide switch) provided around the driver's seat (for example, a steering wheel or an instrument panel) can be adopted. However, the present invention is not limited to this, and various pointing devices (for example, a mouse or a touch pad), a keyboard, and a touch panel can also be adopted as the input device 101. The input device 101 may be an operation unit of a mobile device (for example, a smartphone) or an operation unit of a car navigation system.

The vehicle further includes a notification device 102. The notification device 102 is configured to perform a predetermined notification process to a user (for example, a driver) when requested by the HVECU 62. Examples of the notification device 102 include a display device (for example, a meter panel or a head-up display), a speaker, and a lamp. The notification device 102 may be a display unit of a mobile device (for example, a smartphone) or a display unit of a car navigation system.

The input device 101 is configured to receive input of the traveling mode from the user. The user can switch the traveling mode of the vehicle through the input device 101. In this embodiment, a standard mode and a power mode are adopted as the traveling modes. The standard mode is a traveling mode in which the engine 13 is operated while balancing output power and fuel consumption. The power mode is a traveling mode in which the engine 13 is operated with priority given to output power over fuel consumption. The driving mode is not limited to the standard mode and the power mode. For example, the eco mode may be further adopted as the driving mode. The eco mode is a traveling mode in which the engine 13 is operated with priority given to fuel efficiency over output power.

The input device 101 is configured to set the traveling mode input by the user among the standard mode and the power mode in the HVECU 62. The storage device 62c stores the mode information. The mode information is information indicating the traveling mode of the vehicle (and by extension, the traveling mode set in the HVECU 62). The input device 101 can set a new traveling mode in the HVECU 62 by rewriting the mode information. The travel control unit 621 identifies the travel mode of the vehicle with reference to the mode information in the storage device 62c, and controls the travel of the vehicle in the travel mode.

When the traveling mode of the vehicle is the standard mode, the HVECU 62 determines the required driving force (and thus the required engine power) so that the fuel consumption does not deteriorate. Therefore, when the amount of acceleration required by the driver becomes large, the output power of the engine 13 may be limited in order to prevent deterioration of fuel efficiency. On the other hand, when the traveling mode of the vehicle is the power mode, the limitation of the output power for fuel consumption is relaxed. The HVECU 62 determines the required driving force (and thus the required engine power) with priority given to the amount of acceleration required by the driver. Therefore, when the required acceleration amount from the driver becomes large, there is a high possibility that the torque corresponding to the required acceleration amount is output to the drive wheels 24. In this way, in the power mode, a larger power than in the standard mode can be output from the engine 13.

The HVECU 62 may be configured to notify the notification device 102 of the traveling mode indicated by the mode information in the storage device 62c. The HVECU 62 may display the traveling mode on the meter panel, for example. When the notification device 102 notifies the traveling mode, the user can grasp which of the first start control and the second start control is executed when the engine is started.

FIG. 10 is a flowchart showing a processing procedure of engine start control executed by the HVECU 62. The process shown in this flowchart is executed, for example, when the EV running is finished and the HV running is started. In EV traveling, the vehicle travels with the engine 13 stopped.

With reference to FIG. 10 together with FIGS. 5 and 9, in step 10 (hereinafter, also simply referred to as “S”) 10, whether or not the sudden acceleration of the vehicle is required is determined by the sudden acceleration determination unit 622. .. More specifically, the sudden acceleration determination unit 622 determines that the sudden acceleration of the vehicle is required when a predetermined requirement (hereinafter, also referred to as “rapid acceleration requirement”) is satisfied. In this embodiment, if the traveling mode of the vehicle is in the power mode, the rapid acceleration requirement is satisfied, and if the traveling mode of the vehicle is not in the power mode, the rapid acceleration requirement is not satisfied. The sudden acceleration determination unit 622 confirms the mode information in the storage device 62c, and determines whether or not the traveling mode of the vehicle is the power mode.

When sudden acceleration of the vehicle is required (YES in S10), the first start control unit 623 executes the first start control in S21 to S24 described below.

In S21, the first start control unit 623 identifies the cylinder 40 (hereinafter, also referred to as “target cylinder”) stopped in the compression stroke by using the previous stop crank angle in the storage device 62c.

In S22, the first start control unit 623 cranks the engine 13 by the MG 14, and the injector 46 executes in-cylinder fuel injection into the target cylinder in a compression stroke. Further, the first start control unit 623 ignites the target cylinder by the ignition device 45 after injecting the fuel in the cylinder to cause the first explosion. The timing of in-cylinder fuel injection (more specifically, compression stroke injection) is, for example, immediately after cranking. However, the present invention is not limited to this, and the fuel injection for the initial explosion in the first start control may be performed immediately before the cranking or may be performed at the same time as the cranking. The ignition timing for the first explosion is determined according to the fuel injection timing. The ignition timing for the first explosion in the first start control may be, for example, immediately after passing through TDC (top dead center). The engine rotation speed at the time of the first explosion in the first start control is lower than the initial explosion speed in the second start control, for example, about 300 rpm to 400 rpm.

In S23, the first start control unit 623 executes the ignition retard angle while assisting the traveling driving force of the vehicle by the MG15. The first start control unit 623 can make up for the shortage of the traveling driving force due to the ignition retard angle by the MG 15. After the first explosion, the traveling control unit 621 executes normal engine combustion control (for example, fuel injection control and ignition control of the engine 13). However, while the ignition retard is executed by the process of S23, the ignition is performed at a timing later than the ignition timing in the normal combustion control (for example, the ignition timing at which the engine torque is maximized).

In S24, the first start control unit 623 determines whether or not the predetermined end condition is satisfied. Then, during the period until the end condition is determined to be satisfied (that is, the period determined to be NO in S24), the processing of S23 (that is, the ignition retard angle and the traveling driving force assist by MG15) continues. Will be done.

In this embodiment, the end condition is satisfied after a predetermined time (hereinafter, also referred to as “ignition retardation time”) has elapsed from the start of the ignition retardation. Ignition retard information indicating an appropriate ignition retard time is created in advance by experiment or simulation and stored in the storage device 62c. For example, ignition retard angle information indicating an ignition retard angle time at which the turbine rotation speed of the turbocharger 47 sufficiently increases may be created. Further, the ignition retard angle information may be created in consideration of emission. The ignition retard angle time indicated by the ignition retard angle information may be a fixed value or may be variable depending on the state of the engine 13 (for example, the engine cooling water temperature). The ignition retard angle information may be a numerical value or a map.

The end condition is not limited to the above and can be set arbitrarily. For example, the termination condition may be satisfied when the turbine rotation speed of the turbocharger 47 detected by the turbine rotation speed sensor 71 rises to a predetermined value or more.

On the other hand, when the sudden acceleration of the vehicle is not required (NO in S10), the second start control unit 624 executes the second start control in S31 to S33 described below.

In S31, the second start control unit 624 makes the throttle valve 49 fully closed, and the MG 14 cranks the engine 13.

In S32, the second start control unit 624 determines whether or not the rotation speed (Ne) of the engine 13 exceeds a predetermined initial explosion speed by cranking in S31. The initial explosion speed can be set arbitrarily, but may be, for example, a rotation speed selected from the range of 600 rpm to 700 rpm. Then, when the rotation speed of the engine 13 exceeds the initial explosion speed due to cranking (YES in S32), the second start control unit 624 injects fuel for the initial explosion into any of the cylinders 40a to 40d in S33. And ignite.

According to the second start control described above, since the initial explosion of the engine 13 is performed in a state where the engine rotation speed is high and the amount of air is small, it becomes easy to reduce the start shock.

The series of processes shown in FIG. 10 ends regardless of whether the result is YES in S24 or the process in S33 is executed. When the process of FIG. 10 is completed, the traveling control unit 621 starts to execute the normal engine combustion control.

FIG. 11 is a diagram for explaining the operation of the hybrid vehicle according to the embodiment of the present disclosure. As shown by the line L10 with reference to FIG. 11, in this example, the vehicle is EV traveling before the timing t1, and the EV traveling is switched to the HV traveling at the timing t1. That is, the timing t1 corresponds to the time of HV transition. The HVECU 62 starts (ON) cranking the engine 13 by the MG 14 at the timing t1.

FIG. 12 is a collinear diagram showing an example of the relationship between the rotation speeds of the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 20 during cranking. When the MG 14 is generated with torque in the forward rotation direction while the engine 13 is stopped, the torque in the direction of rotating the engine 13 in the forward rotation is generated in the sun gear S with reference to FIG. As a result, the rotation speed of the engine 13 increases. The MG 14 can utilize such an action to start the engine 13 (that is, cranking) while the vehicle is running. Immediately after the start of cranking, in order to generate torque in the forward rotation direction in the MG 14 in the negative rotation state, the MG 14 operates as a generator, and the electric power generated by the MG 14 is input to the battery 18. Further, when the MG 14 cranks while the vehicle is running, a reaction force (that is, a torque in the direction of decelerating the vehicle) is generated in the ring gear R along with the cranking operation of the MG 14. Therefore, when the MG 14 cranks while the vehicle is running, the HVECU 62 increases the torque of the MG 15 to suppress such a reaction force.

With reference to FIG. 11 again, when the HVECU 62 executes the first start control, the first start control unit 623 of the HVECU 62 performs the first explosion at the timing t2, as shown by the line L12. The cylinder 40 to be detonated is a cylinder among the cylinders 40a to 40d that is stopped in the compression stroke (more specifically, the cylinder that was stopped in the compression stroke when the engine 13 was stopped last time), and is a fuel for the first explosion. The injection is performed in a compression stroke. Ignition for the first explosion occurs during the same combustion cycle as fuel injection (eg, immediately after fuel injection). Therefore, the time from the start of cranking (that is, timing t1) to the first explosion is short. The first explosion increases the engine torque (and thus the engine speed). As shown by the line L11, the first start control unit 623 stops (OFF) the cranking by the MG 14 as the engine speed increases. Further, as shown by the line L13, the ignition retard angle is started at the timing t2 and continues until the timing t4. During execution of the ignition retard, the MG 15 is driven by the first start control unit 623. Although the engine torque (and thus the traveling driving force) decreases due to the ignition retard angle, the traveling driving force can be supplemented by the torque of the MG 15. The timing t4 is a timing at which the end condition of the ignition retard angle is satisfied.

When the HVECU 62 executes the second start control, the second start control unit 624 of the HVECU 62 performs the initial explosion at the timing t3, as shown by the line L22. The timing t3 is a timing at which the rotation speed of the engine 13 exceeds the initial explosion speed Th due to cranking. As shown by the line L21, the second start control unit 624 stops (OFF) the cranking by the MG 14 as the engine speed increases. The cranking time is longer in the second start control than in the first start control. As shown by line L23, no ignition retard is performed in the second start control.

As described above, in the hybrid vehicle according to this embodiment, the HVECU 62 is configured to be able to execute the first start control. In the first start control, the engine 13 is cranked by the MG 14, and the cylinder 40, which was stopped in the compression stroke when the engine 13 was stopped last time, is injected with in-cylinder fuel in the compression stroke and ignited after the in-cylinder fuel injection. By doing so, the first explosion is caused (S22 in FIG. 10), and the ignition retard angle is executed while assisting the traveling driving force by MG15 (S23 in FIG. 10). In such a first start control, the cylinder 40 stopped in the compression stroke is injected with the in-cylinder fuel in the compression stroke, so that the engine 13 can be detonated at an early stage. Further, as the initial explosion of the engine 13 becomes faster, the exhaust temperature (and thus the flow velocity of the exhaust) rises at an early stage. Then, as the exhaust flow rate and the exhaust flow velocity increase, the rotational speed of the turbine 53 of the turbocharger 47 increases, so that the engine torque rises faster. Further, the ignition retard is executed to suppress the starting shock. During the period in which the ignition retard angle is continued, the traveling driving force is assisted by the MG 15, so that the shortage of the traveling driving force due to the execution of the ignition retard angle is suppressed. Further, during the period in which the ignition retard angle is continued, the exhaust temperature becomes high and the rotation speed of the turbine 53 of the turbocharger 47 tends to increase. As described above, according to the above-mentioned first start control, when the engine is started, it is possible to accelerate the rise of the engine torque while suppressing the start shock.

According to the process of FIG. 10, when the traveling mode of the vehicle is the power mode (YES in S10), the engine 13 is started by the first start control (S21 to S24), while the traveling mode of the vehicle is standard. In the mode (NO in S10), by starting the engine 13 by the second start control (S31 to S33), the engine 13 can be started in a mode suitable for the situation at the time of starting the engine. ..

The rapid acceleration requirement shown in the above embodiment is only an example. In the above embodiment, the following requirement (C) is adopted as the rapid acceleration requirement, but in place of or in addition to the requirement (C), at least one of the following requirement (A) and requirement (B) is adopted. May be good.
(A) The required acceleration amount is equal to or greater than a threshold value (hereinafter, also referred to as "first threshold value") when shifting from EV driving to HV driving.
(B) The power output by the HVECU 62 to the engine 13 when shifting from EV driving to HV driving is equal to or greater than a threshold value (hereinafter, also referred to as "second threshold value").
(C) The driving mode of the vehicle is set to the power mode when shifting from EV driving to HV driving.

Each of the first threshold value and the second threshold value may be a fixed value or may be variable depending on the situation of the vehicle (for example, the traveling mode). Since the HVECU 62 is configured to output the above-mentioned required engine power to the engine 13, it is determined whether or not the requirement (B) is satisfied based on whether or not the required engine power is equal to or greater than the second threshold value. May be good.

The HVECU 62 may execute the process of FIG. 10 only at the time of HV transition, or may execute the process of FIG. 10 at all engine starts including the time of HV transition.

The configuration of the engine 13 is not limited to the configuration shown in FIG. 2, and can be appropriately changed. For example, the position of the throttle valve 49 in the intake passage 41 may be between the air flow meter 50 and the compressor 48. Further, the cylinder layout is not limited to the series type, and may be a V type or a horizontal type.

Each cylinder of the engine is further equipped with a fuel injection valve for in-cylinder injection (for example, an injector 46) and a fuel injection valve for injecting fuel into the intake port (that is, a fuel injection valve for port injection). May be good. The fuel injection in the second start control may be an intake port injection. The fuel injection for the engine initial explosion in the second start control may be performed in the intake stroke.

The number of cylinders and the number of valves can be changed arbitrarily. In a vehicle having one cylinder, the control device may be configured to adjust the amount of rotation of the crankshaft when the engine is stopped to stop the crankshaft in the compression stroke of the cylinder. Alternatively, the control device does not execute the first start control when there is no cylinder stopped in the compression stroke when the engine was stopped last time, and executes the first start control when there is a cylinder stopped in the compression stroke when the engine was stopped last time. It may be configured to do so.

The embodiments disclosed this time should be considered as exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the embodiment described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10 Drive unit, 13 engine, 13a engine body, 14, 15 MG, 16 1st inverter, 17 2nd inverter, 18 battery, 19 PCU, 20 planetary gear mechanism, 21 output gear, 22 output shaft, 23, 30 rotor shaft , 24 drive wheels, 25 counter shafts, 26 driven gears, 27, 31 drive gears, 28 differential gears, 29 ring gears, 32, 33 drive shafts, 36 oil pumps, 38 electric oil pumps, 40, 40a, 40b, 40c, 40d cylinders. , 41 Intake Passage, 42 Exhaust Passage, 43 Intake Port, 44 Exhaust Port, 45 Ignition Plug, 46 Injector, 47 Supercharger, 48 Compressor, 49 Throttle Valve, 50 Air Flow Meter, 51 Intercooler, 53 Turbine, 53a Shaft, 54 WGV mechanism, 55 WGV, 56 start catalytic converter, 57 aftertreatment device, 58 EGR device, 59 EGR passage, 60 EGR valve, 61 EGR cooler, 62 HVECU, 62a processor, 62b RAM, 62c storage device, 63 MGECU, 64 Engine ECU, 65 converter, 66 accelerator sensor, 67 vehicle speed sensor, 68 MG1 rotation speed sensor, 69 MG2 rotation speed sensor, 70 engine cooling water temperature sensor, 71 turbine rotation speed sensor, 72 boost pressure sensor, 73 SOC sensor, 74 MG1 Temperature sensor, 75 MG2 temperature sensor, 76 INV1 temperature sensor, 77 INV2 temperature sensor, 78 catalyst temperature sensor, 79 supercharger temperature sensor, 101 input device, 102 notification device, 130 cam angle sensor, 131 crank shaft, 132 crank angle Sensor, 133 Timing rotor, 133a Protrusion, 133b Missing tooth, 401 Combustion chamber, 402 Piston, 403 Connecting rod, 431 Intake valve, 432 Intake cam shaft, 433 Intake cam, 434 Timing rotor, 434a, 434b, 434c Protrusion , 441 Exhaust valve, 442 Exhaust cam shaft, 443 Exhaust cam, 621 Travel control unit, 622 Sudden acceleration judgment unit, 623 First start control unit, 62 4 Second start control unit, C carrier, P pinion gear, R ring gear, S sun gear.

Claims (8)

An engine that generates driving force and
The first electric motor configured to crank the engine and
The second electric motor that generates driving force and
It includes the engine, the first electric motor, and a control device for controlling the second electric motor.
The engine includes at least one cylinder, intake and exhaust passages connected to all the cylinders, and a supercharger.
The cylinder includes a fuel injection valve for injecting fuel in the cylinder and an ignition device for igniting.
The supercharger includes a compressor provided in the intake passage and a turbine provided in the exhaust passage.
The control device cranks the engine by the first electric motor, and executes the in-cylinder fuel injection in the compression stroke to the cylinder that was stopped in the compression stroke when the engine was stopped last time, and injects the in-cylinder fuel. A hybrid vehicle configured to be capable of executing a first start control that executes an ignition retard angle while assisting a traveling driving force by the second electric motor after the first explosion by igniting the engine later. The control device cranks the engine by the first electric motor, and when the rotation speed of the engine exceeds a predetermined speed, fuel injection and ignition for the initial explosion are performed on any of the at least one cylinder. The second start control is configured to be executable
The control device performs the first start control and the second when shifting from the EV traveling performed by the second electric motor to the HV traveling performed by the engine and the second electric motor with the engine stopped. The hybrid vehicle according to claim 1, wherein any of the start control is selected and executed. It also has an accelerator sensor that detects the amount of acceleration requested by the user.
The hybrid vehicle according to claim 2, wherein the control device is configured to select the first start control if the required acceleration amount is equal to or greater than a threshold value when shifting from the EV travel to the HV travel. The second or third aspect of the present invention, wherein the control device is configured to select the first start control if the power output to the engine is equal to or greater than a threshold value when shifting from the EV travel to the HV travel. Hybrid vehicle. The control device is configured to perform the HV driving in a plurality of driving modes including a power mode in which the output power is prioritized over fuel consumption to operate the engine.
The control device is configured to select the first start control if the traveling mode of the hybrid vehicle is the power mode when shifting from the EV traveling to the HV traveling. The hybrid vehicle according to any one of 4. The engine includes a plurality of the cylinders, and further includes a crankshaft common to the plurality of cylinders.
The control device is configured to be able to detect the rotational position of the crankshaft, and is configured to store the rotational position of the crankshaft when the engine is stopped.
In the first start control, the control device is configured to identify a cylinder stopped in the compression stroke among the plurality of cylinders by using the rotation position of the crankshaft stored at the time of the previous stop of the engine. The hybrid vehicle according to any one of claims 1 to 5. The hybrid vehicle according to any one of claims 1 to 6, wherein the control device is configured to end the ignition retard when a predetermined end condition is satisfied after starting the ignition retard. .. Each of the engine and the first electric motor is mechanically connected to the drive wheels of the hybrid vehicle via a planetary gear.
Any of claims 1 to 7, wherein the planetary gear and the second electric motor are configured such that the power output from the planetary gear and the power output from the second electric motor are combined and transmitted to the drive wheels. The hybrid vehicle described in item 1.

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