JP2012086685A - Control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fuel consumption of a hybrid vehicle.SOLUTION: A control device of a hybrid vehicle includes: a starting means for controlling a first electric rotating machine to perform the cranking of an internal combustion engine when the requested driving force reaches the predetermined threshold in a case when the hybrid vehicle travels in an EV (Electric Vehicle) traveling mode; a crank position detection means for detecting the crank position while the internal combustion engine is stopped; and a crank position control means for controlling the first electric rotating machine so that the crank position is the target crank position based on the detected crank position before the cranking of the internal combustion engine. The control device further includes a threshold changing means for estimating the starting time required for the start of the internal combustion engine based on the detected crank position, and changing the predetermined threshold according to the estimated starting time so that the power supplied to the first electric rotating machine and a second electric rotating machine from a battery approaches the output limit of the battery when the start of the internal combustion engine is completed.

Description

  The present invention relates to the technical field of hybrid vehicle control devices.

  This type of hybrid vehicle includes an engine and a motor as a power source, and an EV (Electric Vehicle) travel mode in which only the power from the motor travels as a travel mode, and an HV (Hybrid) that travels by the power of both the engine and the motor. Vehicle) traveling mode (see, for example, Patent Document 1).

  For example, in Patent Document 1, when the target driving torque (or required driving force) of a hybrid vehicle becomes larger than a cranking request determination threshold, engine cranking is performed, and after cranking, the target driving torque is determined to be an engine start request. It is disclosed to start the engine when it exceeds the value. Furthermore, Patent Document 1 discloses that the engine start request determination value is increased as the amount of change in the accelerator opening is smaller. Further, for example, Patent Document 2 discloses that in a hybrid vehicle, the engine start time is measured, and the engine stop is prohibited when the measured start time is equal to or greater than a predetermined threshold value. ing. Further, Patent Document 2 discloses that the friction is estimated based on the engine water temperature and the torque converter oil temperature, and the predetermined threshold value is changed according to the estimated magnitude of the friction.

  On the other hand, in this type of hybrid vehicle, the crank position of the engine crankshaft (that is, the crank angle) can reduce the vibration before the engine is cranked in order to reduce the vibration generated when the engine is started. In some cases, crank position control is performed to control the crankshaft so as to achieve a correct target crank position.

  In such crank position control, the time required to set the crank position as the target crank position based on the difference between the crank position before the crank position control (hereinafter referred to as “pre-start crank position” as appropriate) and the target crank position. Is different. Therefore, the engine start time required for starting the engine varies depending on the crank position before starting. For this reason, when control is performed to start the engine when the required driving force becomes larger than a predetermined threshold (for example, the above-described cranking request determination threshold), the predetermined threshold is, for example, an EV driving motor or cranking In order to prevent the output power of the battery that supplies power to the motor from exceeding the output limit, the engine start time is set to a constant value corresponding to the start crank position at which the engine start time is longest.

JP 2010-149783 A JP 2001-159347 A

  However, when the predetermined threshold value is set to a constant value corresponding to the start crank position at which the engine start time becomes the longest, as described above, depending on the start crank position, the engine start time is short, so that the battery surplus There is a possibility that the engine start-up is completed in a state where the electric power is relatively large. As a result, there is a technical problem that switching from the EV traveling mode to the HV traveling mode is performed at an early stage, and it becomes difficult to improve fuel consumption.

  The present invention has been made in view of the above-described problems, for example, and an object of the present invention is to provide a hybrid vehicle control device capable of improving fuel consumption.

  In order to solve the above-described problems, a control apparatus for a hybrid vehicle according to the present invention includes an internal combustion engine, a first rotating electrical machine capable of cranking the internal combustion engine, a second rotating electrical machine, and the first and second rotating electrical machines. And a battery for supplying electric power to the vehicle, and an EV travel mode in which the internal combustion engine is stopped by the power from the second rotating electrical machine in a state where the internal combustion engine is stopped, and a power from the internal combustion engine and the second rotating electrical machine. And a hybrid vehicle control device that controls a hybrid vehicle having an HV traveling mode that travels in accordance with the above-described driving force required for the hybrid vehicle when the hybrid vehicle is traveling in the EV traveling mode. The internal combustion engine is controlled by controlling the first rotating electrical machine to crank the internal combustion engine when a predetermined threshold value is reached. Starting means for starting the engine, crank position detecting means for detecting the crank position of the internal combustion engine while the internal combustion engine is stopped, and based on the detected crank position before the internal combustion engine is cranked, Crank position control means for controlling the first rotating electric machine so that the crank position of the internal combustion engine becomes a target crank position, and estimating a start time required for starting the internal combustion engine based on the detected crank position; According to the estimated start time, the predetermined threshold is changed so that the electric power supplied from the battery to the first and second rotating electrical machines approaches the output limit of the battery when the start of the internal combustion engine is completed. Threshold value changing means.

  The hybrid vehicle according to the present invention includes, as travel modes, an EV travel mode that travels with power from the second rotating electrical machine while the internal combustion engine is stopped, and an HV travel mode that travels with power from the internal combustion engine and the second rotary electrical machine. And have. In the hybrid vehicle according to the present invention, when the internal combustion engine is started, the internal combustion engine is cranked by the first rotating electrical machine. The battery is, for example, a secondary battery (storage battery), and supplies power to the first and second rotating electrical machines.

  According to the hybrid vehicle control apparatus of the present invention, when the hybrid vehicle is traveling in the EV traveling mode, the starting means has a predetermined driving force required for the hybrid vehicle when the hybrid vehicle is accelerated, for example. When the threshold value is reached, the internal combustion engine is started by controlling the first rotating electrical machine to crank the internal combustion engine. The “predetermined threshold value” according to the present invention is set as a required driving force value at which the start of the internal combustion engine should be started in consideration of, for example, power that can be output by the second rotating electrical machine, battery output limitation, and the like. As will be described later, particularly in the present invention, the predetermined threshold value is changed by the threshold value changing means.

  In the present invention, the crank position of the internal combustion engine (that is, the crank angle of the crank shaft of the internal combustion engine) is detected by the crank position detection means while the internal combustion engine is stopped. Here, “when the internal combustion engine is stopped” according to the present invention means a state where the internal combustion engine is not outputting power and the rotation of the crankshaft of the internal combustion engine is stopped.

  Further, in the present invention, the first rotating electrical machine is operated at the crank position so that the crank position of the internal combustion engine becomes the target crank position based on the crank position detected by the crank position detecting means before the internal combustion engine is cranked. It is controlled by the control means. Here, the “target crank position” according to the present invention is a crank position capable of reducing vibration during cranking of the internal combustion engine, for example, floor vibration generated when the rotational speed of the internal combustion engine passes through the resonance band. Is set in advance based on experiments or the like as a crank position capable of suppressing the above. The “target crank position” according to the present invention may be set as one crank position where vibration can be reduced, or may be set as a range of crank positions where vibration can be reduced. Further, “before the internal combustion engine is cranked” according to the present invention means a period before the first rotating electrical machine is controlled by the starting means so as to crank the internal combustion engine. It means a period immediately before the stopped internal combustion engine is cranked by the first rotating electrical machine.

  That is, in the present invention, when the hybrid vehicle is traveling in the EV traveling mode, for example, when the required driving force reaches a predetermined threshold during acceleration of the hybrid vehicle, first, the crank position of the internal combustion engine is set to the target crank position. Then, the first rotating electrical machine is controlled by the crank position control means so that the first rotating electrical machine is controlled to crank the internal combustion engine by the starting means, and the start of the internal combustion engine is started.

  Particularly in the present invention, the predetermined threshold value is changed by the threshold value changing means. The threshold value changing means estimates the start time required for starting the internal combustion engine based on the crank position detected by the crank position detecting means, and the first and the second times from the battery when the start of the internal combustion engine is completed according to the estimated start time. The predetermined threshold is changed so that the electric power supplied to the second rotating electrical machine approaches the output limit of the battery. The “starting time” according to the present invention is the time when the starting of the internal combustion engine is completed from the time when the required driving force reaches a predetermined threshold (that is, the time when the internal combustion engine is in a complete explosion state where it can independently rotate continuously). The first rotating electrical machine is controlled by the crank position detecting means so that the crank position becomes the target crank position, and the first rotating electrical machine is controlled by the starting means so as to crank the internal combustion engine. Including time to be played. During the start-up period from when the required driving force reaches a predetermined threshold until the start-up of the internal combustion engine is completed, the first rotating electrical machine is operated by each of the crank position control means and the start means. Electric power is supplied to the first rotating electrical machine in addition to the rotating electrical machine. Further, when the required driving force increases during the start-up period, the electric power supplied from the battery to the second rotating electrical machine increases.

  Here, suppose that the starting time is the longest so that the electric power supplied from the battery to the first and second rotating electrical machines does not exceed the output limit of the battery (that is, the first and second when the start of the internal combustion engine is completed). When the predetermined threshold value is set to a constant value with reference to the case where the most electric power is required to operate the rotating electrical machine), the internal combustion engine is operated with a relatively large surplus power of the battery when the starting time is short. The start of the engine is completed.

  However, in the present invention, particularly, as described above, the threshold value changing means estimates the starting time based on the crank position detected by the crank position detecting means, and when the start of the internal combustion engine is completed according to the estimated starting time. The predetermined threshold is changed so that the electric power supplied from the battery to the first and second rotating electrical machines approaches the output limit of the battery. Therefore, when the start time is relatively short while the electric power supplied from the battery to the first and second rotating electrical machines during the start-up period of the internal combustion engine does not exceed the output limit of the battery, If the start time is relatively long, it can be set as a relatively small value. Therefore, for example, as compared with the case where the predetermined threshold is set to a constant value as described above, the time during which power is output from the internal combustion engine (that is, the time during which the hybrid vehicle travels in the HV travel mode) is shortened. In other words, the time during which the hybrid vehicle travels in the EV travel mode can be lengthened. As a result, the fuel efficiency of the hybrid vehicle can be improved.

  As described above, according to the hybrid vehicle control device of the present invention, the fuel efficiency of the hybrid vehicle can be improved.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

1 is a schematic configuration diagram conceptually showing the configuration of a hybrid vehicle according to a first embodiment. 1 is a schematic view illustrating a cross-sectional configuration of an engine according to a first embodiment. It is a graph for demonstrating the outline of the engine starting control at the time of driving mode switching concerning 1st Embodiment. It is a flowchart which shows the flow of the engine starting control at the time of driving mode switching which concerns on 1st Embodiment. It is a figure which shows notionally an example of the map for determining engine starting request | requirement power based on 1st Embodiment. It is the graph (the 1) for demonstrating the relationship between the crank angle before start which the map which concerns on 1st Embodiment prescribes | regulates, and engine starting request | requirement power. It is a graph (the 2) for demonstrating the relationship between the crank angle before start which the map which concerns on 1st Embodiment prescribes | regulates, and engine starting request | requirement power. It is a graph for demonstrating the engine starting control at the time of the drive mode switch which concerns on a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
A hybrid vehicle control device according to a first embodiment will be described with reference to FIGS. 1 to 7.

  First, an overall configuration of a hybrid vehicle to which the hybrid vehicle control device according to the present embodiment is applied will be described with reference to FIG.

  FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the hybrid vehicle according to the present embodiment.

  In FIG. 1, a hybrid vehicle 10 according to this embodiment includes an ECU (Electronic Control Unit) 100, an engine 200, a motor generator MG1, a motor generator MG2, a power split mechanism 300, a PCU (Power Control Unit) 400, a battery 500, a vehicle speed. A sensor 12, an accelerator opening sensor 13, a speed reduction mechanism 30, an axle 40 and wheels 50 are provided.

  The ECU 100 is an electronic control unit that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is configured to be able to control the entire operation of the hybrid vehicle 10. The ECU 100 is configured to be able to execute various controls in the hybrid vehicle 10 according to a control program stored in a ROM or the like, for example. The ECU 100 functions as an example of a “hybrid vehicle control device” according to the present invention. Specifically, the ECU 100 functions as an example of each of “starting means”, “crank position control means”, and “threshold changing means” according to the present invention.

  The engine 200 is a gasoline engine as an example of the “internal combustion engine” according to the present invention, and is configured to function as a power source of the hybrid vehicle 10. Here, the detailed configuration of the engine 200 will be described with reference to FIG.

  FIG. 2 is a schematic view illustrating a cross-sectional configuration of the engine 200. The “internal combustion engine” according to the present invention includes, for example, a two-cycle or four-cycle reciprocating engine, and has at least one cylinder. In the combustion chamber inside the cylinder, various types such as gasoline, light oil, or alcohol are used. An engine configured to be able to take out the force generated when the air-fuel mixture containing fuel burns as a driving force through a physical or mechanical transmission means such as a piston, a connecting rod, and a crankshaft, as appropriate. It is a comprehensive concept. As long as such a concept is satisfied, the configuration of the “internal combustion engine” according to the present invention is not limited to that of the engine 200 and may have various aspects.

  In FIG. 2, an engine 200 burns an air-fuel mixture through an ignition operation by an ignition device 202 in which a part of a spark plug (not shown) is exposed in a combustion chamber in a cylinder 201, and an explosive force due to such combustion. The reciprocating motion of the piston 203 that occurs in response to the above is converted into the rotational motion of the crankshaft 205 via the connecting rod 204.

  In the vicinity of the crankshaft 205, a crank position sensor 206 as an example of the “crank position detecting means” according to the present invention is provided. The crank position sensor 206 is a sensor configured to be able to detect the rotational position of the crankshaft 205, that is, the crank angle. The crank position sensor 206 is electrically connected to the ECU 100 (see FIG. 1), and the detected crank angle is grasped by the ECU 100 at a constant or indefinite period.

  The engine 200 is an in-line four-cylinder engine in which four cylinders 201 are arranged in series in a direction perpendicular to the paper surface. However, since the configurations of the individual cylinders 201 are equal to each other, in FIG. Only the cylinder 201 will be described. Further, the number of cylinders and the arrangement form of each cylinder in the “internal combustion engine” according to the present invention are not limited to those of the engine 200 as long as the above-described concept is satisfied, and may take various forms, for example, 6 cylinders, 8 cylinders Alternatively, a 12-cylinder engine may be used, or a V-type, a horizontally opposed type, or the like may be used.

  In the engine 200, air sucked from the outside passes through the intake pipe 207 and is guided into the cylinder 201 through the intake port 210 when the intake valve 211 is opened. On the other hand, the fuel injection valve of the injector 212 is exposed at the intake port 210, so that fuel can be injected into the intake port 210. The fuel injected from the injector 212 is mixed with the intake air before and after the opening timing of the intake valve 211 to become the above-described mixture.

  The fuel is stored in a fuel tank (not shown), and is supplied to the injector 212 via a delivery pipe (not shown) by the action of a feed pump (not shown). The air-fuel mixture combusted inside the cylinder 201 becomes exhaust, and is led to the exhaust pipe 215 via the exhaust port 214 when the exhaust valve 213 that opens and closes in conjunction with the opening and closing of the intake valve 211 is opened.

  On the other hand, on the upstream side of the intake port 210 in the intake pipe 207, a throttle valve 208 capable of adjusting the intake air amount related to the intake air guided through a cleaner (not shown) is disposed. The throttle valve 208 is configured such that its drive state is controlled by a throttle valve motor 209 electrically connected to the ECU 100. The ECU 100 basically controls the throttle valve motor 209 so as to obtain a throttle opening corresponding to the opening of an accelerator pedal (not shown) (hereinafter referred to as “accelerator opening” as appropriate). It is also possible to adjust the throttle opening degree without the intention of the driver (driver) via the operation control of the motor 209. That is, the throttle valve 208 is configured as a kind of electronically controlled throttle valve.

  A three-way catalyst 216 is installed in the exhaust pipe 215. The three-way catalyst 216 is configured to reduce NOx (nitrogen oxides) in the exhaust discharged from the engine 200 and at the same time to oxidize CO (carbon monoxide) and HC (hydrocarbon) in the exhaust. It is. In addition, the form which a catalyst apparatus can take is not limited to such a three-way catalyst, For example, instead of or in addition to the three-way catalyst, various catalysts such as an NSR catalyst (NOx storage reduction catalyst) or an oxidation catalyst are installed. May be.

  An air-fuel ratio sensor 217 configured to be able to detect the exhaust air-fuel ratio of the engine 200 is installed in the exhaust pipe 215. Further, a water temperature sensor 218 for detecting the cooling water temperature related to the cooling water (LLC) circulated and supplied to cool the engine 200 is disposed in the water jacket installed in the cylinder block that houses the cylinder 201. ing. The air-fuel ratio sensor 217 and the water temperature sensor 218 are electrically connected to the ECU 100, and the detected air-fuel ratio and cooling water temperature are grasped by the ECU 100 at a constant or indefinite detection cycle. .

  Returning to FIG. 1, the motor generator MG1 is a motor generator as an example of the “first rotating electrical machine” according to the present invention, and converts a power running function that converts electrical energy into kinetic energy, and converts kinetic energy into electrical energy. It has a regeneration function. Motor generator MG1 is configured to function as a generator for charging battery 500 or a generator for supplying electric power to motor generator MG2 and an electric motor for cranking engine 200.

  The motor generator MG2 is a motor generator as an example of the “second rotating electrical machine” according to the present invention. Like the motor generator MG1, the motor generator MG2 converts a power running function into kinetic energy, and converts the kinetic energy into electrical energy. Has regenerative function to convert. The motor generator MG2 is mainly configured to function as an electric motor that assists (supplements) the output of the engine 200, and can transmit power to the axle 40 via the reduction mechanism 30 including various reduction gear devices such as a differential. It is configured. The axle 40 is connected to wheels 50 that are drive wheels of the hybrid vehicle 10.

  The motor generators MG1 and MG2 described above are configured as, for example, synchronous motor generators. For example, the motor generators MG1 and MG2 include a rotor having a plurality of permanent magnets on an outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field. Although it has the structure with which it comprises, it may have another structure.

  PCU 400 converts DC power extracted from battery 500 into AC power and supplies it to motor generators MG1 and MG2, and also converts AC power generated by motor generators MG1 and MG2 into DC power and supplies it to battery 500. This is a control unit that includes an inverter or the like that is configured to be capable of individually controlling power input / output between the battery 500 and each motor generator. The PCU 400 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100.

  Battery 500 is a rechargeable storage battery that functions as a power supply source related to power for powering motor generators MG1 and MG2.

  Power split device 300 is a planetary gear (planetary gear mechanism) configured to be able to distribute the output of engine 200 to motor generator MG1 and axle 40. For example, the power split mechanism 300 is disposed between a sun gear provided at the center, a ring gear provided concentrically on the outer periphery of the sun gear, and the sun gear and the ring gear, while rotating on the outer periphery of the sun gear. A plurality of revolving pinion gears and a carrier that supports the rotation shaft of each pinion gear are provided. The sun gear is coupled to the rotor of motor generator MG1 so as to share its rotational axis, and the rotational speed thereof is equivalent to the rotational speed of motor generator MG1. Further, the ring gear is connected to the axle 40 via the speed reduction mechanism 11, and the rotational speed thereof is equivalent to the rotational speed of the axle 40. Further, the carrier is connected to the crankshaft 205 of the engine 200, and the rotational speed thereof is equivalent to the rotational speed of the engine 200. In this case, the power split mechanism 300 is a planetary gear mechanism having a plurality of rotational elements having a differential relationship with each other, and has two rotational degrees of freedom, and the rotational speed of two elements of the sun gear, the carrier, and the ring gear is determined. In some cases, the number of rotations of the remaining one rotation element is inevitably determined.

  The vehicle speed sensor 12 is a sensor configured to be able to detect the vehicle speed of the hybrid vehicle 10. The vehicle speed sensor 12 is electrically connected to the ECU 100, and the detected vehicle speed is grasped by the ECU 100 at a constant or indefinite period.

  The accelerator opening sensor 13 is a sensor configured to be able to detect the accelerator opening of an accelerator pedal (not shown) provided in the hybrid vehicle 10. The accelerator opening sensor 13 is electrically connected to the ECU 100, and the detected accelerator opening is grasped by the ECU 100 at a constant or indefinite period.

  Next, an outline of the engine start control that is executed by the ECU 100 when the travel mode is switched will be described with reference to FIG.

  FIG. 3 is a graph for explaining an outline of engine start control at the time of traveling mode switching.

  In FIG. 3, the hybrid vehicle 10 has an EV travel mode and an HV travel mode as travel modes. EV travel mode is a travel mode in which the vehicle travels with the power from motor generator MG2 while engine 200 is stopped. The HV travel mode is a travel mode in which the vehicle travels with power from the engine 200 and the motor generator MG2. When the required driving force required for hybrid vehicle 10 (that is, the driving force to be output to axle 40) is relatively low, ECU 100 sets the traveling mode to the EV traveling mode, and the required driving force is relatively high. In this case, the traveling mode is set to the HV traveling mode. FIG. 3 shows an example in which the required driving force increases with time when the hybrid vehicle 10 is accelerated from a stopped state, and the traveling mode is switched from the EV traveling mode to the HV traveling mode. The ECU 100 specifies the required driving force based on the accelerator opening detected by the accelerator opening sensor 13 and the vehicle speed detected by the vehicle speed sensor 12.

  The ECU 100 starts engine start control for starting the engine 200 at a time point t1 when the required driving force increases during the acceleration of the hybrid vehicle 10 and reaches the engine start required power. Here, the engine start required power is an example of a “predetermined threshold value” according to the present invention. As a value of the required driving force at which engine start control should be started, for example, the power that can be output by the motor generator MG2, the battery 500 It is set by the EUC 100 in consideration of the output limit Wout (that is, the maximum value of the power that is allowed to discharge the battery 500). As will be described later, the engine start required power is determined by the ECU 100 based on the crank angle detected by the crank position sensor 206 while the engine 200 is stopped and the map M shown in FIG.

  ECU 100 performs cranking control for controlling motor generator MG1 to crank engine 200 as engine start control. Further, in the present embodiment, ECU 100 controls motor generator MG1 so that the crank angle of crankshaft 205 becomes the target crank angle based on the crank angle detected by crank position sensor 206 before cranking control. Crank angle alignment control is performed. Here, the target crank angle is an example of the “target crank position” according to the present invention, and it is experimentally determined beforehand as a crank angle capable of suppressing floor vibration that occurs when the rotation speed of the engine 200 passes through the resonance band. Is set based on. Therefore, by performing crank angle alignment control before cranking control, vibration during cranking of engine 200 can be reduced.

  That is, when the required driving force increases to the engine start required power, the ECU 100 first performs crank angle alignment control as engine start control, and then performs cranking control. The ECU 100 also performs fuel injection control and ignition timing control in addition to crank angle alignment control and cranking control as engine start control.

  The ECU 100 changes the travel mode from the EV travel mode to the HV travel mode at the time t2 when the engine 200 is completely started by the engine start control (that is, when the engine 200 is in a self-sustained and complete explosion state). Switch.

  As described above, since ECU 100 performs crank angle alignment control and cranking control as engine start control, from time t1 when the required driving force reaches the engine start required power to time t2 when the start of engine 200 is completed. The engine start time, which is the time, includes the time for performing crank angle alignment control and the time for performing cranking control.

  Next, engine start control that is executed by the ECU 100 when the travel mode is switched will be described in detail with reference to FIGS. 4 to 7. Hereinafter, a case will be described in which the required driving force increases with time when the hybrid vehicle 10 accelerates from a stopped state, and the traveling mode is switched from the EV traveling mode to the HV traveling mode.

  FIG. 4 is a flowchart showing a flow of engine start control at the time of traveling mode switching.

  In FIG. 4, when the hybrid vehicle 10 is traveling in the EV traveling mode, first, a crank angle is detected (step S110). Specifically, ECU 100 acquires from crank position sensor 206 the crank angle of crankshaft 205 (hereinafter referred to as “pre-start crank angle” as appropriate) detected by crank position sensor 206 while engine 200 is stopped.

  Next, the ECU 100 determines the engine start request power with reference to a map M as shown in FIG. 5 (step S120).

  FIG. 5 is a diagram conceptually illustrating an example of a map for determining the engine start required power.

  In FIG. 5, a map M is a map that defines the relationship between the crank angle before start and the engine start required power.

  In the map M, the engine start required power increases as the pre-start crank angle is closer to the target crank angle (in other words, the engine start required power decreases as the pre-start crank angle is farther from the target crank angle). The relationship between the crank angle before start and the engine start required power is defined. In the example of FIG. 5, the target crank angle is set to 0 ° ATDC and 180 ° ATDC (= −180 ° ATDC).

  Therefore, the ECU 100 determines the engine start required power as a larger value as the pre-start crank angle is closer to the target crank angle, and determines the engine start required power as a smaller value as the pre-start crank angle is farther from the target crank angle.

  Here, the relationship between the crank angle before start defined by the map M and the engine start required power will be described in detail with reference to FIGS.

  6 and 7 are graphs for explaining the relationship between the pre-start crank angle defined by the map M and the engine start required power. FIG. 6 shows the engine start required power when the crank angle before start is relatively close to the target crank angle and the engine start time is relatively short. FIG. 7 shows the engine start required power when the crank angle before start is relatively far from the target crank angle and the engine start time is relatively long.

  As shown in FIGS. 6 and 7, the map M shown in FIG. 5 includes electric power supplied from the battery 500 to the motor generators MG <b> 1 and MG <b> 2 when the engine 200 is started (that is, the motor generator MG <b> 1 cranks the engine 200. The engine start required power is defined so that the sum of the engine start power, which is the power required for the engine generator MG2, and the power required for the motor generator MG2 to output the required drive force is almost equal to the output limit Wout of the battery 500. ing. In FIG. 6, the engine start time is time T1, the engine start request power is the value P1, the time when the required driving force reaches the engine start request power is time t11, and the time when the start of the engine 200 is completed. Is time 12. In FIG. 7, the engine start time is time T2 (however longer than time T1), the engine start required power is value P2 (however, smaller than value P1), and the required driving force is the engine start required power. Is a time point t21, and a time point when the start of the engine 200 is completed is a time point 22.

  More specifically, the map M is created in advance as described below and stored in the ROM of the ECU 100.

  First, the engine start time is estimated based on, for example, experiments for each crank angle before start. The engine start time increases as the difference between the pre-start crank angle and the target crank angle increases, and the time required for the crank angle alignment control increases, and the engine start time increases as the difference between the pre-start crank angle and the target crank angle decreases. Since the time required for the corner alignment control is shortened, it is shortened. For each estimated engine start time, an engine start request power is determined such that the power supplied from the battery 500 to the motor generators MG1 and MG2 when the start of the engine 200 is completed substantially matches the output limit Wout of the battery 500. In this way, the map M is created by estimating the engine start time for each pre-start crank angle and obtaining the engine start required power in advance according to the estimated engine start time.

  Returning to FIG. 4, after determining the engine start request power with reference to the map M (step S120), it is determined whether or not there is a start request (step S130). In other words, after determining the engine start request power, ECU 100 determines whether the requested driving force has reached the determined engine start request power.

  When it is determined that there is a start request, that is, when it is determined that the required driving force has reached the engine start request power (step S130: Yes), the ECU 100 performs crank angle alignment control (step S140). ). That is, ECU 100 controls motor generator MG1 based on the crank angle before starting so that the crank angle of crankshaft 205 becomes the target crank angle.

  Next, the ECU 100 starts the engine 200 by performing cranking control (S150). When engine 200 is started, the travel mode is switched from EV travel to HV travel mode, and hybrid vehicle 10 travels in HV travel mode.

  On the other hand, when it is determined that there is no start request, that is, when it is determined that the required driving force has not yet reached the engine start request power (step S130: No), the ECU 100 does not perform engine start control. . Thereby, engine 200 is maintained in a stopped state, and hybrid vehicle 10 travels in the EV travel mode.

  Next, the effect by the engine start control at the time of driving mode switching in this embodiment will be described with reference to FIGS.

  6 and 7, particularly in the present embodiment, as described above, the ECU 100 increases the required engine start power as the pre-start crank angle is closer to the target crank angle (that is, the estimated engine start time is shorter). The engine start request power is determined as a smaller value as the pre-start crank angle is farther from the target crank angle (that is, the estimated engine start time is longer). Further, as described above, ECU 100 determines that the electric power supplied from battery 500 to motor generators MG1 and MG2 when starting engine 200 is almost matched with output limit Wout of battery 500.

  That is, ECU 100 supplies the surplus battery power of battery 500 at the time of completion of engine start (ie, battery 500 to motor generators MG1 and MG2) according to the length of engine start time estimated based on the start crank angle. The engine start request power is changed so that the difference between the electric power and the output limit Wout becomes almost zero.

  Therefore, for example, compared with a case where the engine start request power is set to a constant value (that is, when the engine start request power is set as a fixed fixed value and is not changed), the time for outputting the power from the engine 200 is as follows. That is, the time during which the hybrid vehicle 10 travels in the HV travel mode can be shortened, in other words, the time during which the hybrid vehicle 10 travels in the EV travel mode can be lengthened. As a result, the fuel efficiency of the hybrid vehicle 10 can be improved.

  FIG. 8 is a graph for explaining engine start control at the time of driving mode switching according to the comparative example.

  In the comparative example shown in FIG. 8, the engine start required power is set to a constant value. In this case, the time when the required driving force reaches the engine start required power (in other words, the time when the engine start control is started) is the same even when the engine start time is different, and the time when the engine start is completed is The shorter the engine start time, the faster. FIG. 8 shows a case where the engine start time is time T3 and a case where the engine start time is time T4. Time T4 is the longest time among engine start times estimated based on the crank angle before start. Time T3 is shorter than time T4. The time point at which the required driving force reaches the engine start request power is time point t31 in both cases where the engine start time is time T3 and time T4. When the engine start time is time T3, the time point when the engine start is completed is time t32. When the engine start time is time T4, the time point when the engine start is completed is also determined by time t32. It is a late time t33. Further, in this comparative example, when the engine start time is time T4, the engine start request power is set so that the surplus battery power becomes zero when the engine start is completed.

  According to such a comparative example, since the engine start request power is set to a constant value, when the engine start time is relatively short, the engine start is completed with the surplus battery power being relatively large. End up. For this reason, the time during which the hybrid vehicle travels in the EV travel mode is shortened, and the fuel consumption may be deteriorated.

  However, particularly in the present embodiment, as described above, the engine start request power is changed so that the power supplied from the battery 500 to the motor generators MG1 and MG2 approaches the output limit Wout of the battery 500 when the start of the engine 200 is completed. Therefore, the time during which the hybrid vehicle 10 travels in the EV travel mode can be extended, and the fuel consumption can be improved.

  As described above, according to the present embodiment, the fuel efficiency of the hybrid vehicle 10 can be improved.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and control of a hybrid vehicle involving such a change. The apparatus is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 30 ... Deceleration mechanism, 40 ... Axle, 50 ... Wheel, 100 ... ECU, 200 ... Engine, 205 ... Crankshaft, 206 ... Crank position sensor, 300 ... Power split mechanism, 400 ... PCU, MG1, MG2 ... Motor generator, 500 ... Battery

Claims (1)

An internal combustion engine, a first rotating electrical machine capable of cranking the internal combustion engine, a second rotating electrical machine, and a battery for supplying electric power to the first and second rotating electrical machines. Control of a hybrid vehicle for controlling a hybrid vehicle having an EV traveling mode in which the vehicle is driven by power from the second rotating electrical machine in a stopped state and an HV traveling mode in which the vehicle is driven by power from the internal combustion engine and the second rotating electrical machine A device,
When the hybrid vehicle is traveling in the EV traveling mode, the first rotating electrical machine is configured to crank the internal combustion engine when a required driving force required for the hybrid vehicle reaches a predetermined threshold value. Starting means for starting the internal combustion engine by controlling
Crank position detecting means for detecting a crank position of the internal combustion engine while the internal combustion engine is stopped;
Crank position control means for controlling the first rotating electric machine so that the crank position of the internal combustion engine becomes a target crank position based on the detected crank position before the internal combustion engine is cranked;
Based on the detected crank position, a start time required for starting the internal combustion engine is estimated, and according to the estimated start time, when the start of the internal combustion engine is completed, from the battery to the first and second rotating electrical machines. A control device for a hybrid vehicle, comprising: threshold value changing means for changing the predetermined threshold value so that supplied power approaches an output limit of the battery.

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