Vehicle system

Abstract

Vehicle system (10) with: a regenerative braking device (52, 60) which is configured to recover kinetic energy of a vehicle during deceleration of the vehicle in order to convert the kinetic energy into electrical power; an electrical energy storage device (64) which is configured to receive the electrical power; an internal combustion engine (20) with a fuel injection valve (22) and an oil pressure control device (36) which controls an internal combustion engine oil pressure (OP); and a control device (70) which is configured to control the internal combustion engine (20) and the regenerative braking device (52, 60), wherein the control device (70) is configured to: when a depressing of an accelerator pedal is released, when the electrical energy storage device (64) is in an incompletely charged state, to perform fuel cut-off processing to control the fuel injector (22) to stop fuel injection, and to perform regenerative braking processing to actuate the regenerative braking device (52, 60); and, when the accelerator pedal is released when the electrical energy storage device (64) is in a fully charged state, to perform fuel cut-off processing and oil pressure boosting processing to control the oil pressure control device (36) such that the internal combustion engine oil pressure (OP) becomes higher than an oil pressure value which is used when the accelerator pedal is released in the incompletely charged state; wherein the internal combustion engine (20) has a throttle valve (30) arranged in an intake air duct (26), and wherein the control device (70) is configured to perform throttle opening degree increase processing in addition to fuel interruption processing and oil pressure increase processing when accelerator pedal depressurization is removed, when the electrical energy storage device (64) is in the fully charged state and an internal combustion engine speed (NE) is higher than a threshold (NEth), in order to control the throttle valve (30) such that an opening degree (Ta) of the throttle valve (30) becomes greater than an opening degree which is used when accelerator pedal depressurization is removed in the incompletely charged state.

Description

Background of the inventionTechnical field

[0001] The present disclosure relates to a vehicle system and, more particularly, to a vehicle system having a regenerative braking device and an internal combustion engine. State of the art

[0002] For example, JP 2017 - 139 839 A discloses an electric vehicle with a regenerative braking device. JP 2017 - 140 862 A discloses a hybrid vehicle. JP 2015 - 47 923 A discloses a vehicle braking system. Summary of the invention

[0003] According to a vehicle with a regenerative braking device as described in JP 2017-139839 A, regenerative braking can be used to brake the vehicle when accelerator pedal depression is released. However, if an electric energy storage device for charging electric power generated by regenerative braking is in a fully charged state, charging by regenerative braking cannot be performed.

[0004] As a result, when the electric energy storage device is not in the fully charged state, there is a risk that the deceleration rate of the vehicle may decrease and the driver of the vehicle may feel uncomfortable.

[0005] The present disclosure has been made to address the above-described problem, and it is an object of the present disclosure to provide a vehicle system that can reduce a decrease in the degree of deceleration when an electric energy storage device for charging electric power generated by regenerative braking is in a fully charged state compared to when it is not in the fully charged state.

[0006] The object is achieved by a vehicle system having the features of independent claims 1 or 2.

[0007] A vehicle system according to one aspect of the present disclosure includes a regenerative braking device configured to regenerate kinetic energy of a vehicle during deceleration of the vehicle to convert the kinetic energy into electric power, an electric energy storage device configured to store the electric power, an internal combustion engine having a fuel injection valve and an oil pressure control device that controls an engine oil pressure, and a control device configured to control the internal combustion engine and the regenerative braking device.The control device is configured to execute fuel cut processing for controlling the fuel injection valve to stop fuel injection and regenerative braking processing for actuating the regenerative braking device when depression of an accelerator pedal is released when the electric power storage device is in an incompletely charged state, and to execute the fuel cut processing and oil pressure increase processing for controlling the oil pressure control device such that the engine oil pressure becomes higher than an oil pressure value used when depression of the accelerator pedal is released in the incompletely charged state, when depression of the accelerator pedal is released when the electric power storage device is in a fully charged state.

[0008] The internal combustion engine includes a throttle valve disposed in an intake air passage. The control device is configured to, when the accelerator pedal depression is released when the electric energy storage device is in the fully charged state and an engine speed is higher than a threshold, execute throttle opening degree increase processing in addition to the fuel cut processing and the oil pressure increase processing to control the throttle valve such that an opening degree of the throttle valve becomes larger than an opening degree used when the accelerator pedal depression is released in the incompletely charged state.

[0009] A vehicle system according to another aspect of the present disclosure includes a regenerative braking device configured to regenerate kinetic energy of a vehicle during deceleration of the vehicle to convert the kinetic energy into electric power, an electric energy storage device configured to charge the electric power, an internal combustion engine having a fuel injection valve and a throttle valve arranged in an intake air passage, and a control device configured to control the internal combustion engine and the regenerative braking device.The control device is configured to execute fuel cut processing for controlling the fuel injection valve to stop fuel injection and regenerative braking processing for actuating the regenerative braking device when depression of an accelerator pedal is released when the electric power storage device is in an incompletely charged state, and to execute the fuel cut processing and throttle opening degree increasing processing when depression of the accelerator pedal is released when the electric power storage device is in a fully charged state and an engine speed is higher than a threshold value, to control the throttle valve such that an opening degree of the throttle valve becomes larger than an opening degree used when depression of the accelerator pedal is released in the incompletely charged state.

[0010] According to the vehicle system of one aspect of the present disclosure, the fuel cut processing and the oil pressure increase processing are executed when depression of the accelerator pedal is released when the electric energy storage device is in the fully charged state. This oil pressure increase processing controls the oil pressure control device such that the engine oil pressure becomes higher than an oil pressure value used when depression of the accelerator pedal is released in the incompletely charged state. When the engine oil pressure is increased by the oil pressure increase processing, the friction loss torque of the engine becomes higher, and thus the engine braking torque becomes higher. As a result, by increasing the engine braking torque, a decrease in the braking torque of the vehicle due to the fact that regenerative braking cannot be used can be reduced (ie,, complemented). Due to this, a decrease in the degree of deceleration of the vehicle can be reduced. Consequently, the vehicle system of one aspect of the present disclosure can make it difficult for the driver to feel uncomfortable about deceleration due to a change in the SOC (state of charge) of the electric energy storage device.

[0011] Furthermore, according to the vehicle system of another aspect of the present disclosure, the fuel cut processing and the throttle opening degree increase processing are executed when accelerator pedal depression is released when the electric power storage device is in the fully charged state and the engine speed is higher than the threshold. The throttle opening degree increase processing controls the throttle valve such that the opening degree of the throttle valve becomes larger than an opening degree used when accelerator pedal depression is released in the incompletely charged state. In a high-speed region, when the throttle opening degree is increased, an increase amount of friction loss torque becomes larger than a decrease amount of pumping loss torque.

[0012] Thus, according to the throttle opening degree increase processing, the engine braking torque increases. As a result, by increasing the engine braking torque, a decrease in the vehicle's braking torque due to the fact that regenerative braking cannot be used can be reduced (i.e., complemented). Due to this, a decrease in the vehicle's deceleration degree can be reduced. Consequently, the vehicle system of another aspect of the present disclosure can make it possible to make it difficult for the driver to feel uncomfortable about deceleration due to a change in the SOC of the electric energy storage device. Brief description of the drawings Fig. 1 is a schematic diagram for describing an example of the configuration of a vehicle system according to a first embodiment of the present disclosure; Fig. 2A is a graph illustrating a relationship between an SOC (state of charge) of an electric energy storage device, a required total braking torque TE, and the deceleration degree of a vehicle; Fig. 2B is a graph showing a relationship between the SOC of the electric energy storage device, the required total braking torque TE, and the deceleration degree of the vehicle; Fig. 3 is a graph showing a relationship of the consumed engine oil amount with respect to an intake pipe negative pressure and an in-cylinder negative pressure; Fig. 4 is a graph showing a relationship between the sound pressure level of an engine noise and an engine speed NE; Fig. 5 is a graph showing a relationship between a friction loss torque Tf of an internal combustion engine and an internal combustion engine oil pressure OP; Fig. 6 is a flowchart illustrating a routine of processing corresponding to control during deceleration of the vehicle according to the first embodiment of the present disclosure; Fig. 7A is a graph illustrating a relationship between the SOC of the electric energy storage device, the required total braking torque TE, and the deceleration degree of the vehicle with respect to a fully charged state without oil pressure increase processing; Fig. 7B is a graph showing a relationship between the SOC of the electric energy storage device, the required total braking torque TE, and the deceleration degree of the vehicle with respect to the fully charged state with the oil pressure increase processing; Fig. 8 is a flowchart illustrating a routine of processing corresponding to control during deceleration of the vehicle according to a second embodiment of the present disclosure; Fig. 9A is a graph to be used in conjunction with Fig. 9B to describe advantageous effects of control during deceleration of the vehicle according to the second embodiment of the present disclosure; Fig. 9B is a graph to be used in conjunction with Fig. 9A to describe advantageous effects of control during deceleration of the vehicle according to the second embodiment of the present disclosure; Fig. 10 is a graph showing a relationship between a pumping loss torque Tp and the engine speed NE in a comparison between a minimum value Tamin and a maximum value Tamax of a throttle opening degree Ta; Fig. 11 is a graph showing a relationship between a friction loss torque Tf and the engine speed NE in a comparison between the minimum value Tamin and the maximum value Tamax of the throttle opening degree Ta; Fig. 12 is a graph showing a relationship between the friction loss torque Tf and a maximum in-cylinder pressure Pmax; Fig. 13 is a graph showing a relationship between an engine resistance torque Tr and the engine speed NE in a comparison between the minimum value Tamin and the maximum value Tamax of the throttle opening degree Ta; Fig. 14 is a flowchart illustrating a routine of processing corresponding to control during deceleration of the vehicle according to a third embodiment of the present disclosure; and Fig. 15 is a graph to describe an example of a combination of the oil pressure increasing processing and a throttle opening degree increasing processing. Detailed description

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. 1. First embodiment

[0014] First, a first embodiment according to the present disclosure will be described with reference to Fig. 1 to Fig. 7 described. 1-1. Example of a vehicle system configuration

[0015] Fig. 1 is a schematic diagram to describe an example of the configuration of a vehicle system 10 according to the first embodiment of the present disclosure. Fig. The vehicle system 10 shown in Figure 1 is provided with an internal combustion engine 20, a first electric motor generator (M / G1) 50, and a second electric motor generator (M / G2) 52 as the vehicle's power sources. That is, the vehicle system 10 is applied, by way of example, to a hybrid vehicle.

[0016] For example, the internal combustion engine 20 is a spark-ignition, three-cylinder inline engine. However, the internal combustion engine according to the present disclosure may alternatively be a compression-ignition internal combustion engine, and the number and arrangement of its cylinders are not particularly limited. The internal combustion engine 20 is equipped with fuel injection valves 22 and an ignition device 24 (only spark plugs are shown). Each of the fuel injection valves 22 is arranged for the corresponding cylinder and injects fuel, for example, directly into the corresponding cylinder. The ignition device 24 ignites an air-fuel mixture in each cylinder using the spark plug arranged for each cylinder.

[0017] Near an inlet of an intake air passage 26 of the internal combustion engine 20, an air flow sensor 28 is arranged, which outputs a signal in response to the flow rate of air introduced into the intake air passage 26. An electrically controlled throttle valve 30 is arranged in a portion of the intake air passage 26 located downstream of the air flow sensor 28. A throttle opening degree sensor 32, which outputs a signal in response to a throttle opening degree Ta, is attached to the throttle valve 30.

[0018] Furthermore, the internal combustion engine 20 is equipped with an oil pump 34, an oil control valve (OCV) 36, and an oil pressure sensor 38. The oil pump 34 is driven to rotate, for example, by torque of a crankshaft 40, and supplies engine oil (lubricating oil) to individual sections of the internal combustion engine 20. The OCV 36 is arranged at an oil pressure passage, which is not shown. By adjusting the opening degree of the OCV 36, the oil pressure supplied from the oil pump 34 to the individual sections of the internal combustion engine 20 (hereinafter referred to as "engine oil pressure OP") can be controlled. The oil pressure sensor 38 outputs a signal in response to this engine oil pressure OP. Note that the OCV 36 corresponds to one example of the "oil pressure control device" according to the present disclosure.

[0019] Furthermore, the internal combustion engine 20 is equipped with a water temperature sensor 42 and a crank angle sensor 44. The water temperature sensor 42 outputs a signal in response to a temperature THW of the engine cooling water that cools the internal combustion engine 20. The crank angle sensor 44 outputs a signal in response to a crank angle.

[0020] The electric motor generator 50 and the electric motor generator 52 are both electric motors capable of generating electrical power. That is, the electric motor generators 50 and 52 are AC synchronous motor generators that function both as an electric motor that outputs torque using input electrical power and as a generator that converts input mechanical power into electrical power. The first electric motor generator 50 is primarily used as the generator, and the second electric motor generator 52 is primarily used as the electric motor. Hereinafter, for convenience of explanation, the first electric motor generator 50 will be referred to simply as the generator 50, and the second electric motor generator 52 will be referred to simply as the electric motor 52.

[0021] The internal combustion engine 20, the generator 50, and the electric motor 52 are coupled to wheels 58 via the power split device 54 and a speed reducer 56. The power split device 54 is, for example, a planetary gear unit and splits the torque output from the internal combustion engine 20 into torques of the generator 50 and the wheels 58. Described more specifically, in the power split device 54, a sun gear is coupled to the rotation shaft of the generator 50, a planetary carrier is coupled to the crankshaft 40 of the internal combustion engine 20, and a ring gear is coupled to the rotation shaft of the electric motor 52. The torque output from the internal combustion engine 20 or the torque output from the electric motor 52 is transmitted to the wheels 58 via the speed reducer 56. The generator 50 regenerates electrical power using torque supplied from the internal combustion engine 20 via the power split device 54.

[0022] The generator 50 and the electric motor 52 each supply and receive electrical power with an electrical energy storage device 64 via an inverter 60 and a converter 62. The inverter 60 converts the electrical power stored in the electrical energy storage device 64 from direct current (DC) to alternating current (AC) to supply the electric motor 52 with this AC, and converts the electrical power generated by the generator 50 from AC to DC to charge the electrical energy storage device 64. As a result, the electrical energy storage device 64 is charged with the electrical power generated by the generator 50, and the electrical power stored in the electrical energy storage device 64 is discharged when it is consumed by the electric motor 52.

[0023] According to the vehicle system 10 configured as described above, regenerative braking can be performed using the electric motor 52 during deceleration of the hybrid vehicle with the fuel supply to the engine 20 stopped. More specifically, the inverter 60 is controlled so that a power generation load (regenerative load) is applied to the electric motor 52 during deceleration, allowing the electric motor 52 to be driven by the wheels 58 to rotate. As a result, during deceleration, the kinetic energy of the vehicle can be regenerated and converted into electric power. That is, the electric motor 52 and the inverter 60 correspond to one example of the "regenerative braking device" according to the present disclosure. The electric energy storage device 64 stores the above-described electric power generated by this regenerative braking device.In addition, according to the vehicle system 10, by controlling the power supply of the generator 50 during deceleration performed while the supply of fuel to the engine 20 is stopped, a state in which the engine 20 is passively driven to rotate by the rotation of the wheels (drive wheels) 58 can be achieved (ie, an engine braking state) without stopping the rotation of the engine 20. The deceleration of the vehicle described below assumes that the engine 20 is placed in the engine braking state.

[0024] The vehicle system 10 according to the present embodiment is provided with a control device 70 for controlling a powertrain including the internal combustion engine 20, the generator 50, and the electric motor 52. The control device 70 is an electronic control unit (ECU) with at least one processor, at least one memory, and an input / output interface.

[0025] The input / output interface receives sensor signals from various sensors mounted on the internal combustion engine 20 and the hybrid vehicle on which the internal combustion engine 20 is mounted, and also outputs actuation signals to various actuators to control the operation of the internal combustion engine 20 and the hybrid vehicle. The various sensors described above include, in addition to the air flow sensor 28, the throttle opening sensor 32, the oil pressure sensor 38, the water temperature sensor 42, and the crank angle sensor 44 described above, a SOC sensor 72 and an accelerator position sensor 74. The SOC sensor 72 is arranged to measure a charging rate (i.e., SOC: "State of Charge") of the electrical energy storage device 64. The accelerator position sensor 74 outputs a signal in response to a depression amount (i.e., an accelerator position) of an accelerator pedal of the hybrid vehicle.The control device 70 may calculate an engine speed NE using the signal from the crank angle sensor 44.

[0026] Furthermore, the various actuators described above include the fuel injectors 22, the ignition device 24, the throttle valve 30, the OCV 36, the generator 50, and the electric motor 52. Various programs and various data (including maps) for controlling the hybrid vehicle are stored in the memory of the control device 70. The processor executes the programs stored in the memory. As a result, various functions of the control device 70 (such as various engine controls and regenerative braking) are achieved. It should be noted that the control device 70 may alternatively be configured with a plurality of ECUs. 1-2. Control during vehicle deceleration1-2-1. Fuel cut processing

[0027] According to the vehicle system 10 of the present embodiment, the control device 70 executes "fuel cut processing" that controls the fuel injection valves 22 to stop fuel injection for the respective cylinders when accelerator pedal depression is released. Specifically, the fuel cut processing is executed provided a certain execution condition is met (e.g., provided the engine speed NE is higher than or equal to a certain value). During vehicle deceleration after the fuel cut processing is executed, the engine braking state is achieved as a result of the engine 20 being passively driven to rotate by the rotation of the wheels (drive wheels) 58. In this engine braking state, the engine 20 generates braking torque. 1-2-2. Uses and problems of regenerative braking

[0028] The vehicle system 10 is provided with the electric motor 52 and the inverter 60, which serve as the regenerative braking device described above. Therefore, regenerative braking can be used to brake the vehicle (regenerative braking processing) when the fuel-cut processing is executed during deceleration. The electric energy storage device 64 is charged using the electric power generated by the regenerative braking, thereby reducing the power of the engine 20 used to generate the electric power consumed by the electric motor 52. As a result, the fuel efficiency of the engine 20 can be improved.

[0029] Fig. 2A and Fig. 2B are graphs illustrating relationships between the SOC of the electric energy storage device 64, a required total braking torque TE, and the deceleration rate of the vehicle. It should be noted that in Fig. 2A and Fig. 2B, a required engine braking torque Te corresponds to a required value of the braking torque generated by the engine 20 during a fuel-cut operation (i.e., during engine braking operation) at the time of vehicle deceleration. A required regenerative torque Tm corresponds to a required value of the braking torque generated by the electric motor 52 during regenerative braking at the time of vehicle deceleration. Furthermore, the total required braking torque TE corresponds to the sum of the required engine braking torque Te and the required regenerative torque Tm.

[0030] Fig. 2A shows a relationship which is achieved when the electrical energy storage 64 is not in a fully charged state (ie, when the electrical energy storage 64 is in an incompletely charged state), and Fig. Figure 2B shows a relationship that is achieved when the electric energy storage device 64 is in the fully charged state. The "fully charged state" of the electric energy storage device 64 referred to here corresponds to a state in which the SOC of the electric energy storage device 64 is substantially equal to an upper limit value (more precisely, an upper limit value of the SOC within a certain usage range) SOCmax of the SOC (SOC ≈ SOCmax).

[0031] In the Fig. In the example of the incompletely charged state shown in Figure 2A, regenerative braking is used, whereby a braking torque that satisfies both the required engine braking torque Te and the required regenerative torque Tm is applied to the vehicle. As a result, the degree of deceleration D1 is achieved.

[0032] In the Fig. In the example of the fully charged state shown in Figure 2B, the deceleration of the vehicle is calculated starting from the same vehicle speed state as that shown in Fig. 2A is started. If the electric energy storage device 64, which charges the electric power generated by regenerative braking, is in the fully charged state, charging by regenerative braking cannot be performed. As a result, the required regenerative torque Tm, as shown in Fig. 2B cannot be achieved. Therefore, there is a concern that, compared to the example of the incompletely charged state, the vehicle's deceleration rate may decrease, causing discomfort to the vehicle driver.

[0033] Fig. Figure 3 is a graph illustrating a relationship between the amount of engine oil consumed and the intake pipe negative pressure and the in-cylinder negative pressure. To reduce a decrease in the deceleration rate of the above-described vehicle in the fully charged state, the following countermeasures can be taken. That is, a throttle valve can be fully closed, and a variable valve timing device can be controlled so that the intake and exhaust valves are not opened in the initial stage of the intake stroke. However, if this type of countermeasure is taken, the intake pipe negative pressure will increase, and the in-cylinder negative pressure will also increase. As shown in Fig. As shown in Figure 3, the amount of engine oil consumed increases because the amount of engine oil flowing into combustion chambers increases as the intake manifold negative pressure and / or the in-cylinder negative pressure increases. Therefore, there is a concern that the amount of engine oil consumed may become excessive if the countermeasures described above are implemented.

[0034] Fig. Figure 4 is a graph illustrating a relationship between the sound pressure level of an engine noise and the engine speed NE. As one of further countermeasures for reducing a decrease in the deceleration rate of the vehicle described above, the engine speed NE may be increased. As shown in Fig. However, as shown in Figure 4, the number of cycles per unit time increases as the engine speed NE increases. As a result, the sound pressure level of the engine noise increases. In addition, the sound pressure level increases, as shown in Fig. 4, the frequency of the engine noise is higher. Thus, if this countermeasure is used, the engine speed NE during deceleration from a constant vehicle speed will differ depending on whether an electric energy storage device is in a fully charged state. Thus, the engine noise perceived by the driver inside the vehicle will change. As a result, there is a concern that the driver may feel uncomfortable due to this type of variance in the engine noise. 1-2-3. Overview of countermeasures (oil pressure increase processing) according to a first embodiment

[0035] According to the present embodiment, the control device 70 executes the fuel cut processing and the above-described regenerative braking processing when the electric power storage device 64 is in the incompletely charged state when the accelerator pedal depression is released. On the other hand, the control device 70 executes "oil pressure increase processing" described below in addition to the fuel cut processing when the electric power storage device 64 is in the "fully charged state" when the accelerator pedal depression is released.

[0036] Fig. Figure 5 is a graph showing a relationship between a friction loss torque Tf of the engine 20 and an engine oil pressure OP. More specifically, Fig. 5 illustrates a relationship under engine operating conditions where both the engine speed NE and the engine cooling water temperature THW are constant. Note that the friction loss torque Tf corresponds to a loss torque due to the frictional resistance of individual sliding portions of the engine 20 and is included in an "engine resistance torque Tr" according to the present disclosure. The engine resistance torque Tr broadly refers to torques acting against the rotation of the engine 20, including, for example, a pumping loss torque Tp described later and a torque related to accessory drive losses, in addition to the friction loss torque Tf. The above-described required engine braking torque Te is based on this engine resistance torque Tr.

[0037] As in Fig. As shown in Figure 5, the friction loss torque Tf increases as the engine oil pressure OP is higher. This is because the frictional resistance of the individual sliding portions of the engine 20 increases as the engine oil pressure OP is higher.

[0038] The oil pressure increase processing is executed to use the friction loss torque Tf, which increases in conjunction with the engine oil pressure OP, instead of the regenerative torque Tm, which cannot be used in the fully charged state. Specifically, in the example of the oil pressure increase processing executed in the present embodiment, the engine oil pressure OP is increased by a certain increase amount ΔOP. When the engine oil pressure OP is increased by the increase amount ΔOP, the friction loss torque Tf, as shown in Fig. 5, by an increase amount ΔTf. According to the present embodiment, this increase amount ΔTf is used as an increase amount ΔTe of the required engine braking torque Te. 1-2-4. Processing of a control device corresponding to a control during deceleration of a vehicle

[0039] Fig. 6 is a flowchart illustrating a routine of processing corresponding to the control during vehicle deceleration according to the first embodiment of the present disclosure. The control device 70 repeatedly executes the processing according to the present routine at a certain control interval.

[0040] According to the Fig. In the routine shown in Figure 6, the control device 70 first determines, in step S100, whether the accelerator pedal depression is released using the accelerator pedal position sensor 74. As a result, if the determination result from step S100 is negative, the control device 70 ends the current processing cycle. Note that if the accelerator pedal depression is not released, the control device 70 calculates a required total drive torque of the vehicle as a value dependent on the accelerator pedal position. Furthermore, the control device 70 divides the calculated required total drive torque into a required engine torque (positive torque) and a required motor torque (positive torque) of the electric motor 52 in accordance with certain calculation rules.

[0041] On the other hand, if the determination result of step S100 is affirmative, the control device 70 executes the above-described fuel cut processing in step S102. Specifically, the fuel cut processing is executed provided the engine speed NE is higher than or equal to a certain value when the accelerator pedal depression is released.

[0042] The control device 70 then determines, in step S104, whether the SOC of the electric energy storage device 64 is substantially equal to the upper limit value SOCmax. If the determination result from step S104 is negative (i.e., if the electric energy storage device 64 is in the "incompletely charged state"), processing proceeds to step S106.

[0043] In step S106, the control device 70 obtains, for example, using the various sensors described above, each of the measured values ​​of the engine speed NE, an in-cylinder charge air amount (i.e., an engine load) KL, and the engine cooling water temperature THW, which are included in various engine operating state parameters. The in-cylinder charge air amount KL can be determined, for example, by inputting parameters including an intake air flow rate measured by the air flow sensor 28 and the engine speed NE calculated using the crank angle sensor 44 into a known mathematical model of an intake system.

[0044] The control device 70 then calculates, in step S108, the required engine braking torque Te and the required regenerative torque Tm.

[0045] First, the requested engine braking torque Te corresponds to a value of the engine braking torque generated by the engine 20 under a condition such that, for example, the opening degree of the throttle valve 30 is constant at a certain target opening degree (for example, a minimum value Tamin). The control device 70 stores a map (not shown) that defines a relationship of this type of requested engine braking torque Te with respect to the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW. In this step S108, the control device 70 references this type of map and calculates the requested engine braking torque Te depending on the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW, which are determined in step S106.The above-mentioned map can be prepared, for example, by conducting an experiment in advance to obtain the engine braking torque data while changing each value of the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW. Note that the required engine braking torque Te can be calculated based only on the engine speed NE, instead of the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW.

[0046] Furthermore, the requested regenerative torque Tm is determined such that a requested target total braking torque TE is achieved under each engine speed NE, provided that the requested engine braking torque Te determined as described above is generated. The control device 70 stores a map (not shown) relating the values ​​of the requested regenerative torque Tm that can satisfy this type of request to the engine speed NE. In this step S108, the control device 70 references this type of map and calculates the requested regenerative torque Tm depending on the engine speed NE determined in step S106.

[0047] Following step S108, processing proceeds to step S110. In step S110, the control device 70 calculates the total required braking torque TE. More specifically, the sum of the required engine braking torque Te and the required regenerative torque Tm calculated in step S108 is calculated as the total required braking torque TE. Note that, with regard to the control during deceleration according to the present embodiment, the calculation processing of steps S108 and S110 per se is not essential. However, in an example in which ECUs are separately provided for a hybrid system, each controlling the entire system, the engine 20 and the electric motor 52, the hybrid system can acquire the values ​​of the braking torque Te and Tm according to this calculation processing.

[0048] Following step S110, processing proceeds to step S112. In step S112, the control device 70 instructs the minimum value Tamin, which is an example of the predetermined opening degree described above, as a throttle opening degree Ta. As a result, the throttle valve 30 is controlled so that the minimum value Tamin is achieved.

[0049] Further, in step S114, the control device 70 executes regenerative braking to generate the required regenerative torque Tm calculated in step S108. As a result, during the course of vehicle deceleration in response to the release of accelerator pedal depression, both the required engine braking torque Te and the required regenerative torque Tm are achieved, and thus the required total braking torque TE is achieved.

[0050] On the other hand, if the determination result of step S104 is affirmative (i.e., if the electric energy storage device 64 is in the "fully charged state"), the processing proceeds to step S116. In step S116, the control device 70 obtains each of the measured values ​​of the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW using the same processing as in step S106, and also obtains a measured value of the engine oil pressure OP using the oil pressure sensor 38.

[0051] The control device 70 then calculates, in step S118, the required engine braking torque Te and the required regenerative torque Tm. An example of the calculation method of the required engine braking torque Te is as already described in step S108. On the other hand, the calculation of the required regenerative torque Tm is different from the processing of step S108. That is, the processing of this step S118 is executed when the electric power storage 64 is in the fully charged state (i.e., when electric power cannot be supplied to the electric power storage 64 even if electric power is generated by regenerative braking). Due to this, in this step S118, the control device 70 calculates the required regenerative torque Tm as zero.

[0052] The control device 70 then determines, in step S120, whether the engine oil pressure OP is higher than a minimum value OPmin. The minimum value OPmin corresponds to a minimum value of the engine oil pressure OP that can ensure normal operation of the engine 20. If the determination result from step S120 is negative (i.e., if the oil pressure increase processing cannot be performed), the control device 70 ends the current processing cycle. Note that if this determination result is negative, only a braking torque corresponding to the required engine braking torque Te acts on the vehicle during deceleration.

[0053] On the other hand, if the determination result from step S120 is affirmative (OP > OPmin), processing proceeds to step S122. In step S122, the control device 70 calculates a value of the engine oil pressure OP, that is, a basic engine oil pressure OPb, depending on the current engine operating state (NE, KL, THW). The control device 70 stores a map (not shown) that defines a relationship of the basic engine oil pressure OPb with the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW. In this step S122, the control device 70 references this type of map and calculates the basic engine oil pressure OPb depending on the current engine operating state.

[0054] The control device 70 then calculates, in step S124, the opening degree of the OCV 36 (i.e., a required OCV opening degree) necessary to achieve a required engine oil pressure OPr, which is the sum of the base engine oil pressure OPb calculated in step S122 and a predetermined increase amount ΔOP (OPb + ΔOP). Specifically, the increase amount ΔOP is determined in advance such that, under a constant engine speed NE, the increase amount ΔTe does not exceed the value of the required regenerative torque Tm used during deceleration in the incompletely charged state (see step S108). According to the present embodiment, for example, the increase amount ΔOP is a fixed value. However, the increase amount ΔOP may be changed instead of the fixed value in accordance with target parameters such as the engine speed NE.

[0055] The control device 70 stores a map (not shown) that defines a relationship of the OCV opening degree with the required engine oil pressure OPr, the engine speed NE, the in-cylinder charge air amount KL, and the engine cooling water temperature THW. In this step S124, the control device 70 references this type of map and calculates a required OCV opening degree depending on both the current engine operating state and the required engine oil pressure OPr.

[0056] The control device 70 then calculates, in step S126, an increase amount ΔTe of the required engine braking torque Te. This increase amount ΔTe corresponds to an increase amount of the required engine braking torque Te obtained when the engine oil pressure OP, as described with reference to Fig. 5, starting from the base engine oil pressure OPb, the increase amount ΔOP is increased. The relationship between the friction loss torque Tf and the engine oil pressure OP changes as shown in Fig. 5, in accordance with the engine speed Ne and the engine cooling water temperature THW. Based on this, the control device 70 stores a map (not shown) determined such that the relationship between the friction loss torque Tf and the engine oil pressure OP changes in accordance with the engine speed Ne and the engine cooling water temperature THW. In this step S126, the control device 70 uses the relationship of this type of map to calculate the increase amount ΔTe of the required engine braking torque Te, which is obtained when the engine oil pressure OP is increased by the above-described increase amount ΔOP.It should be noted that this increase amount ΔTe can alternatively be calculated to change in accordance with the in-cylinder charge air amount KL in addition to the engine speed NE and the engine cooling water temperature THW.

[0057] The control device 70 then calculates, in step S128, a final requested engine braking torque Te'. Described more specifically, the control device 70 calculates, as the final requested engine braking torque Te', the sum (Te + ΔTe) of the requested engine braking torque Te calculated in step S118 and the increase amount ΔTe calculated in step S126. The control device 70 then calculates, in step S130, a total requested braking torque TE (= final requested engine braking torque Te' + ΔTm) obtained when the engine oil pressure OP is increased by the increase amount ΔOP.

[0058] Subsequently, in step S132, the control device 70 instructs, as the throttle opening degree Ta, the minimum value Tamin, which is an example of the above-described target opening degree, and the processing is similar to that of step S112. The control device 70 then controls the OCV 36 so as to achieve the required OCV opening degree calculated in step S124. Described more specifically, the electric current flowing through the OCV 36 is controlled so as to achieve the required OCV opening degree. It should be noted that the engine speed NE changes during deceleration of the vehicle in conjunction with the progress of the deceleration. According to the processing of the present routine, if the engine speed NE changes, the calculated value of the basic engine oil pressure OPb changes (step S122).Thus, during the deceleration, the required OCV opening degree (step S124) also changes in conjunction with a change in the engine speed NE.

[0059] It should be noted that according to the Fig. 6, the processing of step S108 (ie, a calculation of the required regenerative torque Tm) and the processing of step S114 correspond to an example of the “regenerative braking processing” according to the present disclosure, and the processing of steps S122, S124 and S132 corresponds to an example of the “oil pressure increasing processing” according to the present disclosure. 1-3. Beneficial effects

[0060] Fig. 7A and Fig. 7B are graphs illustrating, with respect to the fully charged state, relationships between the SOC of the electric energy storage device 64, the required total braking torque TE, and the deceleration degree of the vehicle in comparison with the presence and absence of the oil pressure increase processing. Fig. 7A corresponds to an example without the oil pressure increase processing and is therefore the same as Fig. 2B. On the other hand, Fig. 7B an example with the oil pressure increase processing.

[0061] According to the oil pressure increase processing of the present embodiment, when the accelerator pedal depression is released when the electric energy storage 64 is in the fully charged state, the engine oil pressure OP is made higher than an oil pressure value (in the present embodiment, the base engine oil pressure OPb) used when the accelerator pedal depression is released in the incompletely charged state. According to the control of the present embodiment, accompanied by this type of oil pressure increase processing, the final required engine braking torque Te', as shown in Fig. 7B, after the oil pressure increase processing, it is equal to the sum of the required engine braking torque Te according to the base engine oil pressure OPb and the increase amount ΔTe. As described above, the friction loss torque Tf (i.e., the engine resistance torque Tr) in the fully charged state is increased by the increase amount ΔTe, whereby a decrease in the total required braking torque TE due to the fact that regenerative braking cannot be used can be reduced (i.e., complemented) by an increase in the engine braking torque. Due to this, a decrease in the deceleration degree of the vehicle can be reduced.

[0062] According to the control of the present embodiment, contrary to the control described with reference to Fig. 3, the engine resistance moment Tr can be increased without requiring an increase in the intake manifold negative pressure and the cylinder internal negative pressure. As a result, a decrease in the degree of deceleration of the vehicle can be reduced without requiring an increase in the amount of engine oil consumed. Contrary to the above-mentioned Fig. Furthermore, with the countermeasures described in Figure 4, the engine resistance torque Tr can be increased without requiring an increase in the engine speed NE. As a result, during deceleration from a constant vehicle speed, a change in the engine speed NE according to whether the electric energy storage device 64 is in the fully charged state can be prevented or reduced. Consequently, a decrease in the degree of deceleration of the vehicle can be reduced while not causing the driver to feel uncomfortable due to the variability of engine noise. 2. Second embodiment

[0063] Next, a second embodiment according to the present disclosure will be described with reference to Fig. 8 and Fig. 9. In the following explanation it is assumed that the Fig. The configuration shown in Figure 1 is used as an example of the hardware configuration of the vehicle system according to the second embodiment. This also applies to a third embodiment and an example described in Section 4-1, which will be described later. 2-1. Control during deceleration of a vehicle2-1-1. Overview of control during deceleration of a vehicle in a fully charged state

[0064] In the first embodiment described above, a fixed value is used as the increase amount ΔOP of the engine oil pressure OP in the fully charged state. That is, according to the control of the first embodiment, the increase amount ΔTe of the required engine braking torque Te changes depending on the increase amount ΔOP. In contrast, according to the control of the present embodiment, the increase amount ΔTe is determined to be equal to a value of the required regenerative torque Tm used during deceleration in the incompletely charged state (in other words, to be equal to a regenerative torque generated by the regenerative braking processing in the incompletely charged state). Moreover, the increase amount ΔOP of the engine oil pressure OP is determined to satisfy the thus determined increase amount ΔTe. 2-1-2. Processing of a control device corresponding to a control during deceleration of a vehicle

[0065] Fig. Fig. 8 is a flowchart illustrating a routine of processing corresponding to the control during deceleration of the vehicle according to the second embodiment of the present disclosure. The processing from steps S100 to S122, S128 to S134 in the Fig. The routine shown in Figure 8 is as already described in the first embodiment.

[0066] The processing of the Fig. The routine shown in Figure 8 proceeds to step S200 after calculating the base engine oil pressure OPb in step S122. In step S200, the controller 70 calculates the increase amount ΔTe of the requested engine braking torque Te as a value equal to the requested regenerative torque Tm used during deceleration in the incompletely charged state. Specifically, the requested regenerative torque Tm changes in accordance with the engine speed NE, as already described in connection with the processing of step S108. Accordingly, in this step S200, the controller 70 references the map used in the processing of step S108 and determines a map value of the requested regenerative torque Tm associated with the current engine speed NE.Subsequently, the control device 70 calculates the increase amount ΔTe, which is equal to this map value.

[0067] Subsequently, in step S202, the control device 70 calculates the increase amount ΔOP with respect to the base engine oil pressure OPb based on the base engine oil pressure OPb and the increase amount ΔTe calculated in steps S122 and S200, respectively. Specifically, the increase amount ΔOP is calculated to be equal to a value necessary to obtain the increase amount ΔTe (= ΔTf) from a map (not shown) shown in Fig. 5, a relationship between the friction loss torque Tf and the engine oil pressure OP is defined.

[0068] Subsequently, in step S204, the control device 70 calculates the required OCV opening degree necessary to achieve the required engine oil pressure OPr through processing similar to that of step S124. This required engine oil pressure OPr is equal to the sum of the base engine oil pressure OPb calculated in step S122 and the increase amount ΔOP calculated in step S202.

[0069] It should be noted that according to the Fig. In the routine shown in Figure 8, the processing of step S200 corresponds to an example of the "first processing" according to the present disclosure. Furthermore, the processing of steps S202, S204, and S134 corresponds to an example of the "second processing" according to the present disclosure. 2-2. Beneficial effects

[0070] Fig. 9A and Fig. 9B are graphs for describing advantageous effects of control during deceleration of the vehicle according to the second embodiment of the present disclosure. Fig. 9A is the same as Fig. 7B and is associated with the example of the control according to the first embodiment. On the other hand, Fig. 9B is associated with the example of the controller according to the present embodiment.

[0071] As in Fig. As shown in Fig. 9B, according to the oil pressure increase processing of the present embodiment, the engine oil pressure OP is increased such that the increase amount ΔTe of the required engine braking torque Te becomes equal to the value of the required regenerative torque Tm used during deceleration in the incompletely charged state (more specifically, equal to the value that changes in accordance with the engine speed NE). That is, the engine braking torque corresponding to the regenerative torque is complemented by increasing the required engine braking torque Te. As a result, a decrease in the total required braking torque TE due to the fact that regenerative braking cannot be used can be prevented or reduced.Due to this, a change in the deceleration degree of the vehicle according to the SOC of the electric energy storage device 64 (in other words, according to whether the electric energy storage device 64 is in the fully charged state or the incompletely charged state) can be sufficiently reduced. In addition, a change in the deceleration degree of the vehicle according to the SOC can be sufficiently reduced without requiring an increase in the amount of engine oil consumed and without changing the engine noise in accordance with the SOC. 3. Third embodiment

[0072] Next, a third embodiment according to the present disclosure will be described with reference to Fig. 10 to Fig. 14 described. 3-1. Control during deceleration of a vehicle3-1-1. Overview of control during deceleration of a vehicle in a fully charged state

[0073] According to the control of the first embodiment described above, oil pressure increase processing is executed to increase the engine oil pressure OP to increase the required engine braking torque Te in the fully charged state. In contrast, according to the control of the present embodiment, instead of the oil pressure increase processing, "throttle opening degree increase processing" as described below is executed to increase the required engine braking torque Te in the fully charged state. The throttle opening degree increase processing corresponds to the processing to control the throttle valve 30 such that the throttle opening degree Ta becomes larger than an opening degree used when accelerator pedal depression is released in the incompletely charged state.

[0074] Fig. Figure 10 is a graph illustrating a relationship between the pumping loss torque Tp and the engine speed NE in comparison between the minimum value Tamin and a maximum value Tamax of the throttle opening degree Ta. The pumping loss torque Tp corresponds to the sum of the loss torques of all cylinders of the engine 20 due to the pumping loss generated in each cylinder. Fig. The minimum value Tamin shown in Figure 10 corresponds to a minimum value within a target control range of the throttle opening degree Ta, and the maximum value Tamax corresponds to a maximum value within the control range (ie, the fully open degree). As shown in Fig. As shown in Figure 10, the pumping loss torque Tp becomes higher under each engine speed NE when the throttle opening degree Ta is controlled to the minimum value Tamin than when it is controlled to the maximum value Tamax. In addition, as shown in Fig. 10, the difference between them becomes smaller as the engine speed NE becomes higher.

[0075] Next is Fig. 11 is a graph showing a relationship between the friction loss torque Tf and the engine speed NE in a comparison between the minimum value Tamin and the maximum value Tamax of the throttle opening degree Ta. As a result of serious study, the inventor has found that the friction loss torque Tf, in contrast to the pumping loss torque Tp, becomes higher when the throttle opening degree Ta is large than when it is small. Thus, as shown in Fig. 11, the friction loss torque Tf is higher when the throttle opening degree Ta is controlled to the maximum value Tamax than when it is controlled to the minimum value Tamin. The reason why the friction loss torque Tf changes in this way will be explained below with reference to Fig. 12. In addition, as described in Fig. 11, the difference therebetween in a region located on the high-speed side is larger than that in a region located on the low-speed side.

[0076] Fig. 12 is a graph illustrating a relationship between the friction loss torque Tf and the maximum in-cylinder pressure Pmax. The maximum in-cylinder pressure Pmax corresponds to a maximum value of the in-cylinder pressure P during one cycle at the time of engine braking operation (i.e., fuel cut operation) in which combustion of the internal combustion engine 20 is not performed. If the throttle opening degree Ta is increased to increase the in-cylinder charge air amount KL, the maximum in-cylinder pressure Pmax increases. In addition, if the maximum in-cylinder pressure Pmax increases, loads acting on the respective sliding portions of a piston and a connecting rod increase in the compression stroke. Due to this, the friction loss torque Tf, as shown in Fig. 12, is larger when the maximum cylinder pressure Pmax is higher. As a result, the Fig. 11 results shown were achieved.

[0077] Next is Fig. 13 is a graph showing a relationship between the engine resistance moment Tr and the engine speed NE in a comparison between the minimum value Tamin and the maximum value Tamax of the throttle opening degree Ta. Fig. The relationship shown in Figure 13 is determined by Fig. 10 shown relationship to that in Fig. 11 shown relationship. As shown in Fig. As shown in Figure 13, in a region located on the low-speed side, the contribution of the pumping loss torque Tp is larger. Thus, the engine resistance torque Tr becomes higher when the throttle opening degree Ta is controlled to the minimum value Tamin than when it is controlled to the maximum value Tamax. In contrast, if the engine speed NE becomes higher than a value (threshold NEth), the engine resistance torque Tr becomes higher when the throttle opening degree Ta is controlled to the maximum value Tamax than when it is controlled to the minimum value Tamin. It should be noted that the value of the engine resistance torque Tr at each engine speed NE between two Fig. 13 shown diagram values ​​when the throttle opening degree Ta is controlled to a value which lies between the minimum value Tamin and the maximum value Tamax, although this is Fig. 13 is not shown.

[0078] According to the Fig. According to the knowledge shown in Fig. 13, which was acquired by the inventor as a result of serious study, in a high-speed region in which the engine speed NE is higher than the threshold value NEth, the required engine braking torque Te can be increased by executing the throttle opening degree increase processing. In addition, the throttle opening degree Ta used in the throttle opening degree increase processing according to the present embodiment is, for example, the maximum value Tamax (ie, the fully open degree). That is, according to the control of the present embodiment, the throttle valve 30 is controlled such that the maximum value Tamax (ie,, the fully open degree) is reached to increase the required engine braking torque Te when depression of the accelerator pedal is released, when the electric energy storage 64 is in the fully charged state and the engine speed NE is higher than the threshold NEth. 3-1-2. Processing of a control device corresponding to control during deceleration of a vehicle

[0079] Fig. Fig. 14 is a flowchart illustrating a routine of processing corresponding to the control during deceleration of the vehicle according to the third embodiment of the present disclosure. The processing from steps S100 to S114 in the Fig. The routine shown in Figure 14 is as already described in the first embodiment.

[0080] If the determination result from step S104 is positive (SOC ≈ SOCmax), the processing continues in Fig. 14, the routine proceeds to step S300. In step S300, the control device 70 determines the various engine operating state parameters (NE, KL, and THW), similar to the processing of step S106. Then, the processing proceeds to step S302.

[0081] In step S302, the control device 70 determines whether the engine speed NE is higher than the above-described threshold value NEth. The threshold value NEth corresponds to a lower limit of the engine speed NE within an engine speed region in which the value of the engine resistance torque Tr generated when the maximum value Tamax is selected exceeds the value of the engine resistance torque Tr generated when the minimum value Tamin is selected.

[0082] If the determination result from step S302 is negative (NE ≤ NEth), that is, if it can be judged that the engine resistance torque Tr cannot be increased even if the maximum value Tamax is selected, the processing proceeds to step S106. Following steps S106 to S112, the processing of the Fig. 14, the routine proceeds to step S304.

[0083] In step S304, similar to the processing of step S104, the control device 70 determines whether the SOC of the electric energy storage device 64 is substantially equal to the upper limit value SOCmax. As a result, if the determination result of step S304 is negative (i.e., if the electric energy storage device 64 is in the "incompletely charged state"), the control device 70 executes regenerative braking in step S114 such that the required regenerative torque Tm is generated. On the other hand, if the determination result of step S304 is positive (i.e., if it is determined in step S302 that the engine resistance torque Tr cannot be increased even if the maximum value Tamax is selected), the control device 70 skips the processing of step S114 to end the current processing cycle.

[0084] On the other hand, if the determination result of step S302 is affirmative (NE > NEth), that is, if it can be judged that the engine resistance torque Tr can be increased when the maximum value Tamax is selected, the processing proceeds to step S306 after calculating the required engine braking torque Te and the required regenerative torque Tm (zero) in step S118.

[0085] In step S306, the control device 70 determines, using the throttle opening sensor 32, whether the measured value of the current throttle opening Ta is greater than the minimum value Tamin. This processing is performed to determine whether the throttle valve 30 is operating normally. If the determination result of step S306 is negative (Ta ≤ Tamin), the control device 70 ends the current processing cycle.

[0086] On the other hand, if the determination result of step S306 is affirmative (Ta>Tamin), processing proceeds to step S308. In step S308, the control device 70 instructs the maximum value Tamax (ie, the fully open degree) as the throttle opening degree Ta. As a result, the throttle valve 30 is controlled so as to reach the maximum value Tamax.

[0087] Subsequently, in step S310, the control device 70 calculates the increase amount ΔTe of the required engine braking torque Te. More specifically, the control device 70 stores maps (not shown) each of which, as shown in Fig. 13, define a relationship between the engine resistance torque Tr and the engine speed NE. The maps are prepared not only for the minimum value Tamin and the maximum value Tamax, but also for individual intermediate opening degrees located therebetween. In this step S310, the control device 70 first calculates, based on one of the above-described maps, a value Tr1 of the engine resistance torque Tr depending on the throttle opening degree Ta and the engine speed NE at a specific time at which an accelerator pedal depression was recently released. The control device 70 then calculates, based on one of the above-described maps, a value Tr2 of the engine resistance torque Tr depending on the maximum value Tamax and the current engine speed NE.In addition, the control device 70 calculates, as the above-described increase amount ΔTe, an increase amount ΔTr of the engine resistance torque Tr, which is obtained by subtracting the value Tr1 from the value Tr2.

[0088] Subsequently, in step S312, the control device 70 calculates the final requested engine braking torque Te'. Specifically, the control device 70 calculates, as the final requested engine braking torque Te', the sum (Te + ΔTe) of the requested engine braking torque Te calculated in step S118 and the increase amount ΔTe calculated in step S310. Subsequently, in step S314, the control device 70 calculates the total requested braking torque TE (= final requested engine braking torque Te' + ΔTm) obtained when the throttle opening degree Ta is increased to the maximum value Tamax.

[0089] Note that the processing of step S308 corresponds to an example of the “throttle opening degree increase processing” according to the present disclosure. 3-2. Beneficial effects

[0090] When depression of the accelerator pedal is released when the electric energy storage 64 is in the fully charged state, according to the control of the present embodiment, the throttle valve 30 is controlled to have a throttle opening degree Ta (in the present embodiment, the maximum value Tamax) greater than a throttle opening degree Ta (in the present embodiment, the minimum value Tamin) used when depression of the accelerator pedal is released when the electric energy storage 64 is in the incompletely charged state and the engine speed NE is higher than the threshold value NEth. According to the control of the present embodiment, which is accompanied by this type of throttle opening degree increase processing, during deceleration in the fully charged state, the friction loss torque Tf (ie,, the engine resistance torque Tr) is increased by increasing the throttle opening degree Ta, provided the engine speed NE is higher than the threshold NEth. By increasing the throttle opening degree Ta in this way, a decrease in the required total braking torque TE due to the fact that regenerative braking cannot be used can be reduced (i.e., complemented). Consequently, a decrease in the deceleration degree of the vehicle can be reduced. In addition, similar to the first embodiment, a decrease in the deceleration degree of the vehicle can be reduced without requiring an increase in the amount of engine oil consumed, while not causing the driver to feel uncomfortable due to the variance of engine noise. Furthermore, increasing the throttle opening degree Ta is effective to reduce the amount of engine oil consumed.That is, compared with the control of the first embodiment using the oil pressure increase processing, according to the control of the present embodiment, a decrease in the deceleration degree of the vehicle can be reduced while reducing the consumed amount of engine oil. 3-3. Modification Examples 3-3-1. Another example of a throttle opening degree Ta used in throttle opening degree increase processing

[0091] In the example of the throttle opening degree increase processing according to the third embodiment described above, the throttle opening degree Ta is opened to the maximum value Tamax (ie, the fully open degree). However, the throttle opening degree Ta used in the "throttle opening degree increase processing" according to the present disclosure may alternatively be a target opening degree other than the maximum value Tamax (ie, the fully open degree), provided that the throttle opening degree Ta is larger than a throttle opening degree used when accelerator pedal depression is released in the incompletely charged state. 3-3-2. Example of a selection of ways to increase the engine resistance moment Tr depending on the engine speed range

[0092] In the third embodiment described above, the throttle opening degree increase processing is used to increase the engine resistance torque Tr in a high-speed region in which the engine speed NE is higher than the threshold NEth. With respect to this type of control example, additional processing may be included such that oil pressure increase processing similar to that according to the first or second embodiment is executed in a low-speed region in which the engine speed NE is lower than or equal to the threshold NEth. 4. Other Embodiments 4-1. Examples of a Combination of Oil Pressure Increasing Processing and Throttle Opening Degree Increasing Processing

[0093] In an engine speed region (NE > NEth) in which the throttle opening degree increase processing is available, the oil pressure increase processing and the throttle opening degree increase processing may be combined to increase the engine resistance torque Tr in the fully loaded state. More specifically, these may be implemented, for example, as described below with reference to Fig. 15 described example.

[0094] Fig. 15 is a graph to describe an example of a combination of the oil pressure increase processing and the throttle opening degree increase processing. In Fig. 15, an increase amount of the required engine braking torque Te by the throttle opening degree increase processing is denoted as ΔTe1, and an increase amount by the oil pressure increase processing is denoted as ΔTe2. In the Fig. In the example shown in Fig. 15, the oil pressure increase processing and the throttle opening degree increase processing are used together to determine the increase amount ΔTe (=ΔTe1+ΔTe2) which is equal to the value of the required regenerative torque Tm used during deceleration in the incompletely charged state.

[0095] More precisely, according to the Fig. 15, first, the increase amount ΔTe1 is achieved by controlling the throttle opening degree Ta to the maximum value Tamax through the throttle opening degree increase processing. On this basis, for example, through the processing similar to that of step S202 described above, the increase amount ΔOP of the engine oil pressure OP is calculated, which can reach the remaining increase amount ΔTe2. Subsequently, the OCV 36 is controlled so as to achieve the calculated increase amount ΔOP. As a result, an engine braking torque corresponding to the required regenerative torque Tm can be complemented while the oil pressure increase processing and the throttle opening increase processing are jointly used.

[0096] In addition, the oil pressure increase processing and the throttle opening degree increase processing can be used instead of the Fig.15, for example, can be combined as follows. That is, if, for example, the increase amount ΔOP of the engine oil pressure OP is limited, first, the engine oil pressure OP may be increased as much as possible within a possible range. On this basis, if the increase amount ΔTe, which is equal to the value of the required regenerative torque Tm used during deceleration in the incompletely charged state, cannot be obtained by executing only this type of oil pressure increase processing, the throttle opening degree increase processing may be used together therewith.

[0097] Furthermore, in order to achieve the increase amount ΔTe equal to the value of the required regenerative torque Tm used during deceleration in the incompletely charged state, instead of the above-described example, the respective proportions of the increase amount ΔTe1 and the increase amount ΔTe2 to the required regenerative torque Tm may be determined as target values. As one example of a simple combination thereof, the increase amount ΔTe1 and the increase amount ΔTe2 may alternatively be determined as follows, taking into account that the sum of the increase amount ΔTe1 and the increase amount ΔTe2 does not exceed the value of the required regenerative torque Tm.That is, the increase amount ΔTe1 can be determined by the throttle opening degree increase processing using a fixed opening degree (for example, the maximum value Tamax), and the increase amount ΔTe2 can be determined by the oil pressure increase processing using the increase amount ΔOP, which is a fixed value. 4-2. Another example of an oil pressure control device

[0098] In the first to third embodiments and the example described in Section 4-1 described above, the OCV 36 is used as the oil pressure control device. However, the "oil pressure control device" according to the present disclosure may be, for example, a variable displacement device included in a variable displacement oil pump (more specifically, a device that can change the displacement volume of engine oil (i.e., a pump capacity)) instead of the above-described example. Thus, in another example of the oil pressure increase processing, the displacement volume of engine oil can be increased using this type of variable displacement device.It should be noted that, according to this example, the engine resistance torque Tr described above includes not only an increase amount of the friction loss torque Tf due to an increase in the engine oil pressure OP, but also the torque associated with the accessory drive losses due to an increase in the displacement volume. 4-3. Another example of a vehicle system to which control is applied during deceleration of a vehicle

[0099] The controls during vehicle deceleration in the example of the first to third embodiments and the example described in Section 4-1 are directed to the vehicle system 10, which is the hybrid vehicle system including, in addition to the engine 20, the electric motor generators 50 and 52 as vehicle power sources. However, the vehicle system to which the control according to the present disclosure is applied does not always have to be the example of the hybrid vehicle described above, as long as it is provided with a regenerative braking device that recovers the kinetic energy of a vehicle during deceleration to convert it into electric power, and an electric power storage device that charges the electric power.That is, one of further examples of the vehicle system according to the present disclosure may be a vehicle system that has only an internal combustion engine as a power source of the vehicle, and that can perform the regenerative braking using an alternator installed on this internal combustion engine.

[0100] In summary, the present invention relates to a vehicle system including a regenerative braking device; an electric energy storage device configured to charge electric power; an internal combustion engine having a fuel injection valve and an oil pressure control device that controls engine oil pressure; and a control device. The control device is configured to execute fuel cut processing and regenerative braking processing when depression of an accelerator pedal is released when the electric energy storage device is in an incompletely charged state.On the other hand, the control device is configured to execute the fuel cut processing and an oil pressure increase processing when depression of the accelerator pedal is released when the electric power storage device is in a fully charged state, to control the oil pressure control device such that the engine oil pressure becomes higher than an oil pressure value used when depression of the accelerator pedal is released in the incompletely charged state.

Claims

[1] Vehicle system (10) with: a regenerative braking device (52, 60) configured to recover kinetic energy of a vehicle during deceleration of the vehicle to convert the kinetic energy into electrical power; an electrical energy storage device (64) configured to receive the electrical power; an internal combustion engine (20) having a fuel injection valve (22) and an oil pressure control device (36) which controls an internal combustion engine oil pressure (OP); and a control device (70) configured to control the internal combustion engine (20) and the regenerative braking device (52, 60), wherein the control device (70) is configured to: when depression of an accelerator pedal is released when the electric energy storage device (64) is in an incompletely charged state, to execute a fuel cut processing to control the fuel injection valve (22) to stop fuel injection and to execute a regenerative braking processing to actuate the regenerative braking device (52, 60); and, when depression of the accelerator pedal is released when the electric energy storage device (64) is in a fully charged state, to execute the fuel cut processing and an oil pressure increase processing to control the oil pressure control device (36) such that the engine oil pressure (OP) becomes higher than an oil pressure value used when depression of the accelerator pedal is released in the incompletely charged state; wherein the internal combustion engine (20) has a throttle valve (30) arranged in an intake air duct (26), and wherein the control device (70) is configured to execute, in addition to the fuel cut processing and the oil pressure increase processing, throttle opening degree increase processing when depression of the accelerator pedal is released when the electric energy storage device (64) is in the fully charged state and an engine speed (NE) is higher than a threshold value (NEth), to control the throttle valve (30) such that an opening degree (Ta) of the throttle valve (30) becomes larger than an opening degree used when depression of the accelerator pedal is released in the incompletely charged state. [2] Vehicle system (10) with: a regenerative braking device (52, 60) configured to recover kinetic energy of a vehicle during deceleration of the vehicle to convert the kinetic energy into electrical power; an electrical energy storage device (64) configured to receive the electrical power; an internal combustion engine (20) having a fuel injection valve (22) and a throttle valve (30) arranged in an intake air duct (26); and a control device (70) configured to control the internal combustion engine (20) and the regenerative braking device (52, 60), wherein the control device (70) is configured to: when depression of an accelerator pedal is released when the electric energy storage device (64) is in an incompletely charged state, to execute fuel cut processing to control the fuel injection valve (22) to stop fuel injection and to execute regenerative braking processing to actuate the regenerative braking device (52, 60); and when depression of the accelerator pedal is released when the electric energy storage device (64) is in a fully charged state and an engine speed (NE) is higher than a threshold value (NEth), execute the fuel cut processing and a throttle opening degree increase processing to control the throttle valve (30) such that an opening degree (Ta) of the throttle valve (30) becomes larger than an opening degree used when depression of the accelerator pedal is released in the incompletely charged state.

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