JP7192659B2 - hybrid vehicle - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to hybrid vehicles, and more particularly to engine start control in hybrid vehicles.

Japanese Patent Laying-Open No. 2013-113248 (Patent Document 1) discloses a control device that intermittently operates an engine mounted on a hybrid vehicle. In intermittent operation, the controller temporarily stops the engine and then starts it again.

JP 2013-113248 A

By the way, when starting the engine in a situation where rapid acceleration of the vehicle is required (for example, in a situation where the accelerator pedal is strongly depressed by the driver), it is required to accelerate the rise of the engine torque. However, it is not easy to hasten the rise of the engine torque when starting the engine. For example, if the engine torque rises quickly, a shock to the vehicle body (hereinafter referred to as "starting shock") is likely to occur when the engine is started. In addition, in an engine equipped with a turbocharger, the response delay of the supercharger (generally also referred to as "turbo lag") can delay the rise of the engine torque.

In the engine start control described in Patent Literature 1, ignition retardation (that is, control for retarding ignition timing) is executed to suppress knocking. It is thought that the ignition retardation mitigates the starting shock, but delays the rise of the engine torque.

The present disclosure has been made to solve the above-mentioned problems, and its purpose is to be able to accelerate the rise of the engine torque while suppressing the starting shock at the time of starting the engine in a situation where rapid acceleration is required. It is to provide a hybrid vehicle.

A hybrid vehicle according to the present disclosure includes an engine that generates driving force, a first electric motor configured to crank the engine, a second electric motor that generates driving force, and a control device. A controller 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 that performs in-cylinder fuel injection and an ignition device that performs ignition. The supercharger includes a compressor provided in an intake passage and a turbine provided in an exhaust passage. The control device cranks the engine by the first electric motor, executes in-cylinder fuel injection in the compression stroke into the cylinder that stopped in the compression stroke when the engine was stopped last time, and ignites after the in-cylinder fuel injection. It is configured to be able to execute a first start control in which ignition retardation is executed while the second electric motor assists the running driving force.

In the above-described first start control, in-cylinder fuel injection is executed in the compression stroke to the cylinder stopped in the compression stroke, so the engine can be ignited at an early stage. In addition, the earlier the initial combustion of the engine, the sooner the temperature of the exhaust gas (and thus the flow velocity of the exhaust gas) rises. As the exhaust gas flow rate and the exhaust flow velocity increase, the rotation speed of the turbine of the supercharger increases, and the engine torque rises faster.

When the control device performs fuel injection and ignition in a cylinder stopped in the compression stroke and the cylinder first explodes without going through the intake stroke, the starting shock tends to increase. Therefore, in the first start control, the control device executes the ignition retardation to suppress the start shock. Further, during the period in which the ignition retardation is continued, the temperature of the exhaust gas becomes high and the rotation speed of the turbine of the supercharger tends to increase.

When the ignition retardation is executed, the torque generated by combustion in the cylinder becomes smaller. Therefore, the engine torque may be reduced due to the retarded ignition angle, and sufficient driving force may not be obtained. Therefore, in the first start control, the driving force is assisted by the second electric motor during the period in which the ignition retardation is continued. Therefore, the second electric motor can compensate for the running driving force that is lacking due to the retarded ignition angle. As a result, it is possible to ensure sufficient driving force even during the period in which the ignition retardation is continued after the initial combustion of the engine.

According to the first start control described above, it is possible to hasten the rise of the engine torque while suppressing the start shock at the time of starting the engine. Since the above-described hybrid vehicle includes a control device configured to be capable of executing such first start control, the first start control is executed when the engine is started in a situation where rapid acceleration is required, thereby reducing the starting shock. It is possible to hasten the rise of the engine torque while suppressing it.

In-cylinder fuel injection for the initial explosion in the first start control may be performed immediately before cranking, immediately after cranking, or simultaneously with cranking. Ignition for the initial explosion in the first start control may be performed in the expansion stroke. "Previous stop" means the most recent stop. Ignition retardation is a process of retarding ignition timing with respect to 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 for injecting fuel for the first explosion and igniting into one of the cylinders. may be configured to allow When the control device shifts from EV running (that is, running by the second electric motor with the engine stopped) to HV running (that is, running by the engine and the second electric motor), the first start-up It may be configured to select and execute either the control or the second startup control.

During transition from EV driving to HV driving (hereinafter also simply referred to as "during transition to HV"), start-up 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 initially fired at a timing when the engine rotation speed becomes higher than in the first start control, so start shock is less likely to occur than in the first start control. The above-described control device can hasten the rise of the engine torque by the above-described first start control when shifting to the HV, and can also make it difficult for the start shock to occur by the second start control when shifting to the HV. The above-described control device selects and executes either the first start control or the second start control at the time of transition to HV, so that the engine can be started in a manner 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 during the intake stroke or during the compression stroke. The fuel injection in the second start-up control may be in-cylinder injection by the aforementioned fuel injection valve (that is, a fuel injection valve for in-cylinder injection). Further, in a vehicle in which a cylinder further includes a fuel injection valve for injecting fuel into an intake port (that is, a fuel injection valve for port injection), fuel injection in the second start control may be intake port injection.

By executing the first start control in a situation where rapid acceleration of the vehicle is requested, the vehicle can be rapidly accelerated in response to the request for rapid acceleration. More specifically, the control device described above may be configured to execute the first start-up control when the following requirements are satisfied during transition to HV.

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

The above-described control device selects the first start-up control when the power to be output to the engine is equal to or greater than a threshold (hereinafter also referred to as "requirement (B)") when transitioning from EV running to HV running. It may be configured as

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

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

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

The engine may include a plurality of cylinders (that is, cylinders having the fuel injection valves and the ignition devices), and may further include a crankshaft common to the plurality of cylinders. The above control device may be configured 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. The above-described control device may be configured to identify, in the first start control, a cylinder that is stopped in the compression stroke among the plurality of cylinders, using the rotational position of the crankshaft that was stored when the engine was stopped last time. good.

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

The control device described above may be configured to end the ignition retardation when a predetermined end condition is satisfied after the ignition retardation is started.

According to the above configuration, by setting an appropriate end condition in the control device in advance through experiments or simulations, ignition retardation is performed at an appropriate timing (for example, when the turbine rotation speed of the supercharger has sufficiently increased). It is possible to end and return to normal ignition control (eg, MBT control).

Each of the engine and the first electric motor may be mechanically coupled to drive wheels of the hybrid vehicle via planetary gears. The planetary gear and the second electric motor may be 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 driving wheels.

According to the above configuration, the first electric motor and the second electric motor can appropriately perform the above-described cranking and driving force assistance.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a hybrid vehicle capable of speeding up the rise of engine torque while suppressing start-up shock when starting the engine in a situation where rapid acceleration is required.

1 is a diagram showing a vehicle drive system according to an embodiment of the present disclosure; FIG. 1 is a diagram showing a vehicle engine according to an embodiment of the present disclosure; FIG. FIG. 3 is a diagram showing a configuration of each cylinder included in the engine body shown in FIG. 2; FIG. 3 is a diagram showing one combustion cycle of each cylinder included in the engine body shown in FIG. 2; FIG. 1 is a block diagram showing a vehicle control system according to an embodiment of the present disclosure; FIG. FIG. 4 is a collinear diagram showing an example of the relationship between rotational speeds of rotating elements (sun gear, carrier, ring gear) of planetary gears during HV running in the vehicle according to the embodiment of the present disclosure; FIG. 4 is a nomographic diagram showing an example of the relationship between rotational speeds of rotating elements (sun gear, carrier, ring gear) of planetary gears during EV running in the vehicle according to the embodiment of the present disclosure; FIG. 4 is a nomographic chart showing an example of the relationship between rotational speeds of rotating elements (sun gear, carrier, ring gear) of planetary gears while the vehicle is stopped in the vehicle according to the embodiment of the present disclosure; FIG. 2 is a diagram showing details of configurations of a control device and a mechanism for detecting a crank angle in a vehicle according to an embodiment of the present disclosure; FIG. 4 is a flowchart showing a processing procedure of engine start control executed by the vehicle control device according to the embodiment of the present disclosure; FIG. 4 is a diagram for explaining the operation of the hybrid vehicle according to the embodiment of the present disclosure; FIG. FIG. 4 is a nomographic chart showing an example of the relationship between rotational speeds of rotating elements (sun gear, carrier, ring gear) of planetary gears 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 drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. Hereinafter, the electronic control unit is also referred to as "ECU". Moreover, a hybrid vehicle (Hybrid Vehicle) is also called "HV" and an electric vehicle (Electric Vehicle) is also called "EV."

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

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

Battery 18 includes, for example, a secondary battery. A lithium ion battery, for example, can be used as the secondary battery. The battery 18 may include an assembled battery composed of a plurality of electrically connected secondary batteries (for example, lithium ion batteries). In addition, the secondary battery that constitutes the battery 18 is not limited to the lithium ion battery, and may be another secondary battery (for example, a nickel metal hydride battery). As the battery 18, an electrolyte secondary battery may be adopted, or an all-solid secondary battery may be adopted. Any storage device can be used as the battery 18, and a large-capacity capacitor or the like can also be used.

Drive device 10 includes a planetary gear mechanism 20 . Engine 13 and MG 14 are connected to 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 a crankshaft 131 shown in FIG. 3 which will be described later, and when the output shaft 22 rotates, the crankshaft 131 also rotates. In this way, the MG 14 is configured to be capable of cranking 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 line 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 meshing with the sun gear S and the ring gear R, and a carrier C holding the pinion gear P so that it can rotate and revolve. Each of the engine 13 and MG 14 is mechanically connected to drive wheels 24 via a planetary gear mechanism 20 . An output shaft 22 of the engine 13 is connected to the carrier C. As shown in FIG. A rotor shaft 23 of the MG 14 is connected to the sun gear S. Ring gear R is connected to 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. Torque output from the engine 13 is input to the carrier C. As shown in FIG. The planetary gear mechanism 20 is configured to divide and transmit the torque output from the engine 13 to the output shaft 22 to 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 sun gear S receives reaction torque from the MG14. The power output from the planetary gear mechanism 20 (planetary gear) (that is, the power output to the output gear 21) is driven by a driven gear 26, a counter shaft 25, a drive gear 27, a differential gear 28, and a drive shaft 32, which will be described below. 33 to drive wheels 24 .

The drive device 10 further comprises a countershaft 25, a driven gear 26, a drive gear 27, a differential gear 28, a drive gear 31 and drive shafts 32,33. The differential gear 28 corresponds to a final reduction gear 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 . A drive gear 31 attached to the rotor shaft 30 of the MG 15 also meshes with the driven gear 26 . The countershaft 25 is attached to the driven gear 26 and arranged parallel to the axis Cnt. The drive gear 27 is attached to the countershaft 25 and meshes with the ring gear 29 of the differential gear 28 . Driven gear 26 acts to combine torque output from MG 15 to rotor shaft 30 and torque output from ring gear R to output gear 21 . The drive torque thus synthesized is transmitted to the drive wheels 24 via drive shafts 32 and 33 extending left and right from the differential gear 28 .

The drive device 10 further comprises a mechanical oil pump 36 and an electric oil pump 38 . The oil pump 36 is provided coaxially with the output shaft 22 . Oil pump 36 is driven by engine 13 . Oil pump 36 delivers lubricating oil to planetary gear mechanism 20, MG14, MG15, and differential gear 28 when 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 controlled by an HVECU 62 (see FIG. 5), which will be 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. Lubricating oil delivered by each of oil pump 36 and electric oil pump 38 has a cooling function.

FIG. 2 is a diagram showing the configuration of the engine 13. As shown in FIG. Referring to FIG. 2, engine 13 is, for example, an in-line four-cylinder spark ignition internal combustion engine. The engine 13 includes an engine body 13a including four cylinders 40a, 40b, 40c and 40d, and an intake passage 41 and an exhaust passage 42 connected to all cylinders (that is, cylinders 40a, 40b, 40c and 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" unless otherwise specified.

FIG. 3 is a diagram showing the configuration of each cylinder 40 included in the engine body 13a. 3 together with FIG. 2, 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, an exhaust cam 443, An ignition device 45 and an injector 46 are provided. Ignition device 45 includes a spark plug and a boost circuit (not shown), and is configured to ignite the air-fuel mixture in combustion chamber 401 . Injector 46 is configured to perform in-cylinder fuel injection into cylinder 40 (that is, direct fuel injection into cylinder 40). The engine 13 also includes a cam angle sensor 130 , a crankshaft 131 common to the cylinders 40 a , 40 b , 40 c and 40 d , a crank angle sensor 132 and an engine cooling water temperature sensor 70 .

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

When the intake camshaft 432 common to the four cylinders 40 rotates, the intake cams 433 of the respective cylinders 40 also rotate, and the intake valves 431 are driven to open and close by the intake cams 433 . When the exhaust camshaft 442 common to the four cylinders 40 rotates, the exhaust cams 443 of the respective cylinders 40 also rotate, and the exhaust valves 441 are driven to open and close by the exhaust cams 443 . Intake camshaft 432, exhaust camshaft 442, and crankshaft 131 are configured to rotate synchronously by being connected by, for example, 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 consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke (hereinafter referred to as " one combustion cycle") is repeated. In the intake stroke, the piston 402 descends, the intake valve 431 opens, and air is sucked into the cylinder 40 from the intake port 43 . In the compression stroke, piston 402 rises to compress the air in cylinder 40 . During the expansion stroke, combustion and explosion occur in combustion chamber 401 and combustion gases push piston 402 downward. 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 intake camshaft 432 and exhaust camshaft 442 is configured to rotate at half the rotational speed of 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 during the intake stroke and the exhaust valve 441 opens during 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 crankshaft 131). "#1", "#2", "#3" and "#4" represent the 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 stops (and when the rotation of the crankshaft 131 stops), there is one cylinder 40 that stops in each of the intake stroke, compression stroke, expansion stroke, and exhaust stroke.

Referring to FIG. 2 again, the engine 13 includes a turbocharger 47 that uses exhaust energy to supercharge intake air. The supercharger 47 is a turbocharger that includes a compressor 48, a turbine 53, and a shaft 53a. The compressor 48 and the turbine 53 are configured to be connected to each other via a shaft 53a and rotate integrally. The rotational force of the turbine 53 that rotates in response to the exhaust flow discharged from the engine body 13a is transmitted to the compressor 48 via the shaft 53a. The rotation of the compressor 48 compresses intake air directed toward the engine body 13a, and the compressed air is supplied to the engine body 13a. The supercharger 47 is configured to supercharge the intake air by using exhaust energy to rotate the turbine 53 and the compressor 48 .

The compressor 48 is arranged in the intake passage 41 . An air flow meter 50 is provided upstream of the compressor 48 in the intake passage 41 . The airflow meter 50 is configured to output a signal corresponding to the flow rate of air flowing through the intake passage 41 . An intercooler 51 is provided at a position downstream of the compressor 48 in the intake passage 41 . Intercooler 51 is configured to cool intake air compressed by 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 to be able to adjust the flow rate of intake air flowing through the intake passage 41 . The degree of opening of the throttle valve 49 is controlled by an HVECU 62 (see FIG. 5), which will be described later. Air flowing into the intake passage 41 passes through the airflow meter 50, the compressor 48, the intercooler 51, and the throttle valve 49 in this order, and is supplied to each cylinder 40 of the engine body 13a.

The turbine 53 is arranged in the exhaust passage 42 . A WGV (waste gate valve) mechanism 54 is provided in the exhaust passage 42 . The WGV mechanism 54 is configured to bypass the exhaust upstream of the turbine 53 to downstream of the turbine 53 . The WGV mechanism 54 includes a WGV (waste gate valve) 55 capable of adjusting the flow rate of the exhaust guided to the turbine 53 . The degree of opening of the WGV 55 changes the flow rate of exhaust gas flowing into the turbine 53 (and thus the boost pressure). The closer the WGV 55 is closed (that is, the closer it is to the fully closed state), the more the flow rate of the exhaust gas flowing into the turbine 53 and the higher the pressure of the intake air (that is, the supercharging pressure). Exhaust gas discharged from the engine main body 13a passes through either the turbine 53 or the WGV 55, and after harmful substances are removed by the starter catalytic converter 56 and the aftertreatment device 57, it is released to the atmosphere. Aftertreatment device 57 includes, for example, a three-way catalyst.

The engine 13 is provided with an EGR (Exhaust Gas Recirculation) device 58 that causes exhaust gas to flow into the intake passage 41 . The EGR device 58 has an EGR passage 59 , an EGR valve 60 and an EGR cooler 61 . The EGR passage 59 is configured to extract part of the exhaust gas from the exhaust passage 42 as EGR gas and guide it to the intake passage 41 . An EGR valve 60 and an EGR cooler 61 are provided in the EGR passage 59 . The EGR valve 60 is configured to be able to adjust the flow rate of EGR gas flowing through the EGR passage 59 . The EGR cooler 61 is configured to cool EGR gas flowing through the EGR passage 59 .

FIG. 5 is a block diagram showing a vehicle control system according to this embodiment. 5 together with FIGS. 1 and 2, the vehicle control system includes an HVECU 62, an MGECU 63, and an engine ECU 64. As shown in FIG. 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.

Accelerator sensor 66 outputs a signal to HVECU 62 according to the amount of accelerator operation (for example, the amount of depression of an accelerator pedal (not shown)). The accelerator operation amount is a parameter that indicates the amount of acceleration that the driver requests of the vehicle (hereinafter also referred to as "requested acceleration amount"). The greater the amount of accelerator operation, the greater the amount of acceleration requested by the driver. The vehicle speed sensor 67 outputs to the HVECU 62 a signal corresponding to the vehicle speed (that is, the running speed of the vehicle). 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 MG15 to the HVECU 62 . The engine cooling water temperature sensor 70 outputs to the HVECU 62 a signal corresponding to the temperature of cooling water flowing through a 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 supercharger 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 to the HVECU 62 a signal corresponding to the SOC (State of Charge), which is the ratio of the remaining charge amount to the full charge amount (that is, storage capacity) of the battery 18 . The MG1 temperature sensor 74 outputs to the HVECU 62 a signal corresponding to the temperature of the MG14. The MG2 temperature sensor 75 outputs a signal corresponding to the temperature of the MG15 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 to the HVECU 62 a signal corresponding 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, an input/output port and a timer (not shown). A CPU (Central Processing Unit), for example, can be employed as the processor 62a. The RAM 62b functions as a working memory that temporarily stores data processed by the processor 62a. The storage device 62c is configured to be able to save the stored information. The storage device 62c includes, for example, ROM (Read Only Memory) and rewritable nonvolatile memory. The storage device 62c stores programs as well as information used in the programs (for example, maps, formulas, and various parameters). Various controls of the vehicle are executed by the processor 62a executing programs stored in the storage device 62c. Other ECUs (for example, the MGECU 63 and the engine ECU 64) also have the same hardware configuration as the HVECU 62. Although the HVECU 62, the MGECU 63, and the engine ECU 64 are separate in this embodiment, one ECU may have these functions.

HVECU 62 is configured to output a command for controlling engine 13 (for example, an engine operating state command) to engine ECU 64 . Engine ECU 64 is configured to control throttle valve 49 , ignition device 45 , injector 46 , WGV 55 , and EGR valve 60 according to instructions from HVECU 62 . The HVECU 62 can perform engine control 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 according to the request from the HVECU 62 .

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

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

The vehicle is configured to perform HV running and EV running. HV travel is travel performed by the engine 13 and the MG 15 while the engine 13 is generating travel driving force. EV travel is travel performed by MG 15 with engine 13 stopped. When the engine 13 is stopped, combustion in the engine main body 13a is stopped. When the combustion in the engine main body 13a stops, the engine 13 no longer generates combustion energy (and thus driving force for driving the vehicle). The HVECU 62 is configured to switch between EV running and HV running depending on the situation.

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

The HVECU 62 is configured to control the operating point of the engine 13 to the 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 speed. The HVECU 62 obtains the requested engine power based on the driving mode and the requested driving force, and determines the target operating point based on the requested engine power. The HVECU 62, for example, on the coordinate plane of the engine rotation speed and the engine torque, finds the intersection of the line where the engine power is equal to the required engine power (equal power line) and the recommended operation line (for example, the optimum fuel efficiency line). Set the target operating point. The optimum fuel consumption line is a line connecting the operating points of the engine at which the fuel consumption is minimized 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 to be able to continuously change the ratio of the rotation speed of the input element (carrier C) to the rotation speed of the output element (ring gear R). 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 that flows through the MG 14 .

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

FIG. 7 is a collinear chart showing an example of the relationship between the rotational speeds of the sun gear S, the carrier C, and the ring gear R of the planetary gear mechanism 20 during EV running. Referring to FIG. 7, in EV traveling, engine 13 is stopped and MG 15 generates traveling driving force. During EV running, the HVECU 62 controls the ignition device 45 and the injector 46 so that the engine 13 does not perform combustion. Since the EV traveling is performed while the engine 13 is not rotating, the rotational speed of the carrier C becomes 0 as shown in FIG.

FIG. 8 is a nomographic chart showing an example of the relationship between the rotational 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. Referring to FIG. 8, HVECU 62 controls engine 13 and MGs 14 and 15 to set the rotational speeds of sun gear S, carrier C, and ring gear R to 0, thereby stopping the vehicle from running. the car will come to a stop.

By the way, when starting the engine 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 hasten the rise of the engine torque when starting the engine. For example, if the engine torque rises quickly, starting shock (that is, impact on the vehicle body due to engine starting) is more likely to occur. In addition, the response delay of the supercharger can also delay the rise of the engine torque.

Therefore, the vehicle according to the present 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 startup shock is suppressed and the engine torque rises quickly. making it possible.

The HVECU 62 is configured to be able to execute engine start control for rapid acceleration in addition to normal engine start control. As engine start control for rapid acceleration, the engine 13 is cranked by the MG 14, and in-cylinder fuel injection is executed in the compression stroke in the cylinders 40a to 40d that stopped in the compression stroke when the engine 13 was stopped last time. A first start control is employed in which ignition is performed after in-cylinder fuel injection to cause initial explosion, and ignition retardation is executed while driving force is assisted by MG15. As a 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 initial explosion are performed in one 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-up control or the second start-up control when shifting from EV driving to HV driving (that is, when shifting to HV). . The HVECU 62 according to this embodiment corresponds to an example of the "control device" according to the present disclosure.

It should be noted that the timing for executing the selection of the engine start control is not limited to the time of transition to HV. 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 capable of executing idling control that automatically stops the engine 13 when the idling stop condition is satisfied and automatically restarts the engine 13 when the idling stop condition is no longer satisfied. . The HVECU 62 may be configured to select 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 condition is 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 of them are satisfied and ceases to be satisfied if any one of them is not satisfied. The HVECU 62 may be configured to select and execute the first start control when the requested acceleration amount is equal to or greater than a threshold when starting the engine 13 .

FIG. 9 is a diagram showing the details of the configurations 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, the mechanism for detecting the crank angle will be described, and the details of the configuration of the HVECU 62 will be described later.

Referring to FIG. 9 together with FIG. 3, a timing rotor 133 is attached to crankshaft 131 . A plurality of protrusions 133a are formed on the outer circumference of the timing rotor 133 at regular angular intervals (for example, at intervals of 10° CA). A toothless portion 133b is provided on the outer periphery of the timing rotor 133, which is a portion where teeth (projections 133a) are missing. The crank angle sensor 132 is arranged near the timing rotor 133 . Crank angle sensor 132 is configured to detect both forward and reverse rotation. As crank angle sensor 132, for example, an electromagnetic pickup can be employed. As crankshaft 131 rotates, a crank signal corresponding to unevenness of timing rotor 133 (for example, a signal indicating H (high)/L (low) level) is output from crank angle sensor 132 to HVECU 62 . For example, when any projection 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 each time the crankshaft 131 rotates by a predetermined angle (for example, 10° CA). Since the toothless portion 133b is provided at one location on the outer circumference of the timing rotor 133, a long L level period (that is, the L level period corresponding to the toothless portion 133b) appears every 360° CA rotation. The HVECU 62 is configured to calculate the rotational speed of the engine 13 using the 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. As shown in FIG. Cam angle sensor 130 is arranged near timing rotor 434 . As cam angle sensor 130, for example, a sensor using a magnetoresistive element (MRE) can be employed. As intake camshaft 432 rotates, a cam signal corresponding to unevenness of timing rotor 434 (for example, a signal indicating H (high)/L (low) level) is output from cam angle sensor 130 to HVECU 62 . For example, when any one of projections 434a, 434b, 434c passes between intake camshaft 432 and 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 the crank angle in the storage device 62c and is configured to update the crank counter using the crank signal and the cam signal. The HVECU 62 can perform fuel injection and ignition at appropriate timing based on the crank counter.

The crank counter is a counter whose cycle is two revolutions of the crankshaft 131 . Although the reference (0° CA) of the crank counter can be set arbitrarily, in this embodiment, the compression top dead center (compression TDC) of cylinder 40a (#1) is set as the reference (0° CA ) to generate a crank counter. Since the intake camshaft 432 and the crankshaft 131 rotate synchronously, 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 pre-stored in the storage device 62c. For example, the storage device 62c stores the crank angle and cam signal (H level/L level) corresponding to the toothless portion 133b, and when the cam signal is inverted (that is, when it switches from the H level to the L level, and when the L level is changed). 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 checks whether the value of the crank counter is appropriate using the crank position information stored in the storage device 62c, and counts up the crank counter according to the change in the crank angle accompanying the rotation of the crankshaft 131. HVECU 62 also receives a cam edge signal from cam angle sensor 130 each time intake camshaft 432 rotates once. The cam edge signal is a signal output from cam angle sensor 130 when the cam signal is reversed by the terminal end of projection 434b of timing rotor 434, for example. The HVECU 62 resets the crank counter each time it receives a cam edge signal. While the four cylinders 40a, 40b, 40c and 40d, which are out of phase with each other by 180° CA, operate one combustion cycle, the crank counter is counted up (see FIG. 4).

As described above, the HVECU 62 is configured to detect the crank angle. The HVECU 62 is also 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 stops, and reads out 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 when the engine 13 was stopped last time (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 previous stop crank angle as the initial value of the crank counter. When the crankshaft 131 rotates due to cranking when the engine is started and the crank angle sensor 132 detects the crank angle corresponding to the toothless portion 133b, the HVECU 62 reads the crank position information stored in the storage device 62c. is used to check whether the value of the crank counter is appropriate, and if the crank counter is deviated, the crank counter is corrected.

However, in the first start control, in-cylinder fuel injection is performed substantially simultaneously with cranking (for example, immediately after cranking). In the first start control, there is a high possibility that fuel injection and ignition for the initial explosion are performed before the crank angle corresponding to the toothless portion 133b is detected. Therefore, in the first start control, the above-described crank counter is not corrected at the time of initial combustion, and the cylinder 40 stopped in the compression stroke is specified by the previous stop crank angle, and the specified cylinder 40 is injected with fuel and ignited. is performed. Note that even if the ignition timing deviates in the first start control, reverse rotation of the crankshaft 131 is suppressed by cranking.

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

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

Travel control unit 621 is configured to control the travel of the vehicle so as to output the required driving force to drive wheels 24 shown in FIG. 1 while switching between EV travel and HV travel depending on the situation. For example, running control unit 621 performs EV running under low-speed, low-load running conditions, and HV running under high-speed, high-load running conditions. It is determined that the greater the required driving force, the greater the running load. Travel control unit 621 controls the travel of the vehicle by cooperatively controlling engine 13, MG14, and MG15.

Sudden acceleration determination unit 622 is configured to determine whether or not a situation requires rapid acceleration of the vehicle. In this embodiment, sudden acceleration determination unit 622 makes the above determination when EV running is shifted to HV running. Sudden acceleration determination unit 622 determines whether or not a situation requires rapid acceleration of the vehicle based on, for example, the driving mode of the vehicle, which will be described later.

The first start control unit 623 is configured to execute the above-described first start control when the sudden acceleration determination unit 622 determines that the vehicle is in a situation requiring rapid acceleration. The second start control unit 624 is configured to execute the above-described second start control when the sudden acceleration determination unit 622 determines that the vehicle does not require rapid acceleration. 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 a 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 (eg, push button switches or slide switches) provided around the driver's seat (eg, steering wheel or instrument panel) can be employed. However, the input device 101 is not limited to this, and various pointing devices (for example, a mouse or a touch pad), keyboards, and touch panels can be employed as the input device 101 . The input device 101 may be an operation unit of a mobile device (for example, a smart phone) or an operation unit of a car navigation system.

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

The input device 101 is configured to receive a travel mode input from the user. A user can switch the running mode of the vehicle through the input device 101 . In this embodiment, a standard mode and a power mode are adopted as running modes. The standard mode is a driving mode in which the engine 13 is operated while maintaining a balance between output power and fuel consumption. The power mode is a driving mode in which the engine 13 is operated with priority given to output power over fuel consumption. Note that the running mode is not limited to the standard mode and the power mode. For example, an eco mode may be adopted as the running mode. The eco mode is a driving 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 HVECU 62 to the driving mode input by the user, out of the standard mode and the power mode. The storage device 62c stores mode information. The mode information is information indicating the running mode of the vehicle (and thus the running mode set in the HVECU 62). The input device 101 can set a new driving mode for the HVECU 62 by rewriting the mode information. The travel control unit 621 refers to the mode information in the storage device 62c to identify the travel mode of the vehicle, and performs travel control of the vehicle in the travel mode.

When the running mode of the vehicle is the standard mode, the HVECU 62 determines the required driving force (and thus the required engine power) so as not to deteriorate the fuel consumption. Therefore, when the amount of acceleration requested by the driver becomes large, the output power of the engine 13 may be restricted in order to prevent deterioration of fuel consumption. On the other hand, when the running mode of the vehicle is the power mode, restrictions on the output power for fuel efficiency are relaxed. The HVECU 62 prioritizes the amount of acceleration requested by the driver to determine the requested driving force (and thus the requested engine power). Therefore, when the amount of acceleration requested by the driver increases, there is a high possibility that torque corresponding to the amount of acceleration requested will be output to the drive wheels 24 . Thus, in the power mode, the engine 13 can output more power than in the standard mode.

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

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

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

If rapid acceleration of the vehicle is requested (YES in S10), first start control unit 623 executes first start control in steps S21 to S24 described below.

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

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

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

In S24, the first start control section 623 determines whether or not a predetermined termination condition is satisfied. During the period until it is determined that the termination condition is satisfied (that is, the period during which NO is determined in S24), the processing of S23 (that is, the ignition retardation and the driving force assist by the MG 15) continues. be done.

In this embodiment, the termination condition is established after a predetermined time (hereinafter also referred to as "ignition retardation time") has elapsed since the start of ignition retardation. Ignition retardation information indicating an appropriate ignition retardation time is prepared in advance by experiments or simulations and stored in the storage device 62c. For example, ignition retardation information indicating an ignition retardation time at which the turbine rotation speed of the supercharger 47 increases sufficiently may be created. Also, the ignition retardation information may be created in consideration of emissions. The ignition retardation time indicated by the ignition retardation information may be a fixed value, or may be variable according to the state of the engine 13 (for example, engine cooling water temperature). The ignition retardation information may be a numerical value or a map.

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

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

In S31, the second start control unit 624 fully closes the throttle valve 49 and cranks the engine 13 by the MG14.

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 due to the cranking in S31. The initial explosion speed can be set arbitrarily, but may be a rotation speed selected from the range of 600 rpm to 700 rpm, for example. 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 one of the cylinders 40a to 40d in S33. and ignite.

According to the above-described second start control, 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, so start shock can be easily reduced.

The series of processes in FIG. 10 is terminated when the determination in S24 is YES and when the process of S33 is executed. When the process of FIG. 10 is completed, the normal engine combustion control is executed by the travel control unit 621. FIG.

FIG. 11 is a diagram for explaining the operation of the hybrid vehicle according to the embodiment of the present disclosure. Referring to FIG. 11, as indicated by line L10, in this example, the vehicle is in EV travel before timing t1, and switches from EV travel to HV travel at timing t1. That is, the timing t1 corresponds to the HV transition. The HVECU 62 starts (turns ON) the cranking of the engine 13 by the MG 14 at timing t1.

FIG. 12 is a collinear chart showing an example of the relationship between the rotational speeds of the sun gear S, carrier C, and ring gear R of the planetary gear mechanism 20 during cranking. 1 and 12, when the MG 14 is caused to generate torque in the forward rotation direction while the engine 13 is stopped, the sun gear S generates torque in the direction to rotate the engine 13 in the forward direction. As a result, the rotation speed of the engine 13 increases. MG 14 can use this action to start the engine 13 (that is, cranking) while the vehicle is running. Immediately after the start of cranking, the MG 14 in the negative rotation state generates torque in the positive rotation direction, so 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 performs cranking while the vehicle is running, a reaction force (that is, a torque for 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.

Referring to FIG. 11 again, when HVECU 62 executes the first start control, first start control unit 623 of HVECU 62 performs initial explosion at timing t2, as indicated by line L12. The cylinder 40 to be first exploded is the cylinder stopped in the compression stroke among the cylinders 40a to 40d (more specifically, the cylinder stopped in the compression stroke when the engine 13 was stopped last time). Injection takes place in the 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 initial explosion increases the engine torque (and thus the engine rotation speed). As indicated by line L11, first start control unit 623 stops (turns off) cranking by MG 14 as the engine speed increases. Further, as indicated by line L13, ignition retardation starts at timing t2 and continues until timing t4. During execution of the ignition retardation, the MG 15 is driven by the first start control unit 623 . Although the engine torque (and thus the running driving force) decreases due to the ignition retardation, the running driving force can be compensated for by the torque of the MG15. Timing t4 is the timing at which the condition for ending the ignition retardation is met.

When the HVECU 62 executes the second start control, the second start control unit 624 of the HVECU 62 performs the initial explosion at timing t3, as indicated by line L22. Timing t3 is the timing at which the rotation speed of the engine 13 exceeds the initial explosion speed Th due to cranking. As indicated by line L21, second start control unit 624 stops (turns off) cranking by MG 14 as the engine speed increases. The cranking time is longer in the second start control than in the first start control. As indicated by line L23, ignition retardation is not 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 in-cylinder fuel injection is executed in the compression stroke into the cylinder 40 that stopped in the compression stroke when the engine 13 was stopped last time, and ignition is performed after the in-cylinder fuel injection. 10), and the ignition retardation is executed while the driving force is assisted by the MG 15 (S23 in FIG. 10). In such a first start control, in-cylinder fuel injection is executed in the compression stroke into the cylinder 40 that is stopped in the compression stroke, so that the engine 13 can be ignited at an early stage. In addition, the earlier the initial explosion of the engine 13, the sooner the temperature of the exhaust gas (and thus the flow velocity of the exhaust gas) rises. As the exhaust flow rate and the exhaust flow velocity increase, the rotation speed of the turbine 53 of the supercharger 47 increases, so that the engine torque rises faster. Furthermore, the starting shock is suppressed by executing the ignition retardation. During the period in which the ignition retardation is continued, the running driving force is assisted by the MG 15, so that the shortage of the running driving force due to the execution of the ignition retardation is suppressed. Further, during the period in which the ignition retardation is continued, the temperature of the exhaust gas becomes high and the rotational speed of the turbine 53 of the supercharger 47 tends to increase. Thus, according to the above-described first start control, it is possible to hasten the rise of the engine torque while suppressing the start shock at the time of starting the engine.

According to the process of FIG. 10, when the running mode of the vehicle is the power mode (YES in S10), the engine 13 is started by the first starting control (S21 to S24), while the running mode of the vehicle is standard. 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 manner suitable for the situation at the time of starting the engine. .

The rapid acceleration requirement shown in the above embodiment is merely an example. In the above embodiment, the following requirement (C) is adopted as the rapid acceleration requirement, but instead of or in addition to requirement (C), at least one of the following requirements (A) and (B) is adopted. good too.
(A) The requested acceleration amount is equal to or greater than a threshold (hereinafter also referred to as "first threshold") when transitioning from EV travel to HV travel.
(B) The power that the HVECU 62 causes the engine 13 to output when transitioning from EV running to HV running is equal to or greater than a threshold (hereinafter also referred to as "second threshold").
(C) The driving mode of the vehicle is 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 according to vehicle conditions (for example, driving mode). Since the HVECU 62 is configured to output the requested engine power to the engine 13, it determines whether or not the requirement (B) is satisfied based on whether or not the requested engine power is equal to or greater than the second threshold value. good too.

The HVECU 62 may execute the process of FIG. 10 only when shifting to HV, or may execute the process of FIG. 10 during all engine startups including when shifting to HV.

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

Each cylinder included in the engine further includes a fuel injection valve for injecting fuel into an intake port (i.e., a fuel injection valve for port injection) in addition to a fuel injection valve for in-cylinder injection (e.g., injector 46). good too. The fuel injection in the second start control may be intake port injection. Fuel injection for 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 also 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 stopping the engine so that the crankshaft is stopped during the compression stroke of that cylinder. Alternatively, the control device does not execute the first start control if there are no cylinders that stopped in the compression stroke when the engine was stopped last time, and executes the first start control if there are cylinders that stopped in the compression stroke when the engine was stopped last time. may be configured to

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

10 drive unit 13 engine 13a engine body 14, 15 MG 16 first inverter 17 second inverter 18 battery 19 PCU 20 planetary gear mechanism 21 output gear 22 output shaft 23, 30 rotor shaft , 24 drive wheel, 25 countershaft, 26 driven gear, 27, 31 drive gear, 28 differential gear, 29 ring gear, 32, 33 drive shaft, 36 oil pump, 38 electric oil pump, 40, 40a, 40b, 40c, 40d cylinder , 41 intake passage, 42 exhaust passage, 43 intake port, 44 exhaust port, 45 spark 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 Coolant 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 crankshaft, 132 crank angle Sensor, 133 timing rotor, 133a projection, 133b toothless portion, 401 combustion chamber, 402 piston, 403 connecting rod, 431 intake valve, 432 intake camshaft, 433 intake cam, 434 timing rotor, 434a, 434b, 434c projection , 441 Exhaust valve 442 Exhaust camshaft 443 Exhaust cam 621 Driving control unit 622 Sudden acceleration determination unit 623 First start control unit 62 4 2nd starting control part, C carrier, P pinion gear, R ring gear, S sun gear.

Claims (7)

an engine that generates driving force;
a first electric motor configured to crank the engine;
a second electric motor that generates a driving force;
a control device that controls the engine, the first electric motor, and the second electric motor;
The engine includes at least one cylinder, an intake passage and an exhaust passage connected to all the cylinders, and a supercharger;
The cylinder includes a fuel injection valve that performs in-cylinder fuel injection and an ignition device that performs ignition,
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 into the cylinder that stopped in the compression stroke when the engine was stopped last time. The first start control is configured to be capable of performing the ignition retardation while performing the initial ignition by performing ignition later, and performing the ignition retardation while assisting the traveling driving force by the second electric motor ,
The control device cranks the engine by the first electric motor, and when the rotation speed of the engine exceeds a predetermined speed, performs fuel injection and ignition for initial explosion in one of the at least one cylinders. configured to be able to execute the second start control,
The control device performs the first start control and the second drive control when shifting from EV running performed by the second electric motor with the engine stopped to HV running performed by the engine and the second electric motor. A hybrid vehicle configured to select and execute one of the starting controls . further comprising an accelerator sensor for detecting the amount of acceleration requested by the user,
2. The hybrid vehicle according to claim 1 , wherein said control device is configured to select said first start-up control if said required acceleration amount is equal to or greater than a threshold when said EV running is shifted to said HV running. 3. The control device according to claim 1 , wherein the control device is configured to select the first start control if power to be 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 running in a plurality of types of running modes including a power mode in which the engine is operated with priority given to output power over fuel consumption,
The control device is configured to select the first start control if the driving mode of the hybrid vehicle is the power mode when shifting from the EV driving to the HV driving. 4. The hybrid vehicle according to any one of 3 . The engine comprises a plurality of cylinders and further comprises a crankshaft common to the plurality of cylinders,
The control device is configured to be capable of detecting the rotational position of the crankshaft, and is configured to store the rotational position of the crankshaft when the engine is stopped,
The control device is configured to specify, in the first start control, a cylinder stopped in a compression stroke among the plurality of cylinders, using the rotational position of the crankshaft stored when the engine was stopped last time. The hybrid vehicle according to any one of claims 1 to 4 , wherein The hybrid vehicle according to any one of claims 1 to 5 , wherein the control device is configured to end the ignition retardation when a predetermined end condition is satisfied after starting the ignition retardation. . each of the engine and the first electric motor is mechanically coupled to drive wheels of the hybrid vehicle via planetary gears;
7. The planetary gear and the second electric motor according to any one of claims 1 to 6 , wherein the power output from the planetary gear and the power output from the second electric motor are combined and transmitted to the drive wheels. or the hybrid vehicle according to item 1.

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