JP5648461B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device suitable for a hybrid vehicle.

  Conventionally, in addition to the internal combustion engine (engine), a first rotating electrical machine that mainly functions as a generator, and a second rotating electrical machine that mainly functions as an electric motor that supplies power to a drive shaft connected to drive wheels; There is known a hybrid vehicle including a power distribution mechanism that distributes output torque of an internal combustion engine to a first rotating electrical machine side, a drive shaft, and a second rotating electrical machine side. For example, Patent Document 1 discloses a hybrid vehicle that includes an engine and first and second rotating electric machines as a power source, and that can switch a coupling state between the second rotating electric machine and the engine by a clutch. The hybrid vehicle disengages the engine and releases the electric vehicle (EV) by the second rotating electrical machine by releasing the clutch.

  In Patent Document 2, a clutch is provided between the rotating electrical machine and the engine, feedback control is performed according to the differential rotational speed of the clutch, and the gain is changed according to the accelerator opening, so that A technique for adjusting the time in the engaged state (sliding state) is disclosed. Patent Document 3 discloses a technique in which a clutch is provided between a rotating electrical machine and a wheel, and a permissible rotational speed that is an upper limit differential rotational speed that allows engagement of the clutch is obtained according to the vehicle speed.

JP 2000-209706 A JP 2006-123642 A JP 2006-234141 A

  In a hybrid vehicle in which the coupling state of the second rotating electrical machine and the engine can be switched by a clutch, when the engine is started and engaged with the clutch from the EV traveling state in which the clutch is in the released state, depending on the required driving force, There is a possibility that a shock may occur due to the engagement.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for a hybrid vehicle that can suppress the occurrence of a shock at the time of engine start.

In one aspect of the present invention, the engine, the first rotating electrical machine, the second rotating electrical machine, the first rotating element coupled to the first rotating electrical machine, the second rotating electrical machine, and the drive shaft are clutched. A power transmission mechanism comprising a plurality of rotating elements that are differentially rotatable with each other, including a second rotating element that is coupled to the engine, and a third rotating element that is coupled to the engine, and the clutch is released, When the travel mode is switched from the first travel mode in which the engine is stopped and the second rotating electrical machine travels to the second travel mode in which the clutch is engaged and the engine is driven to travel. Control means for bringing the clutch into an engaged state while sliding, wherein the control means changes a slip amount of the clutch in accordance with a required driving force, and the control means rotates the engagement element of the clutch. Number difference When the temperature of the oil in the transmission is lower than a predetermined value, the control means is engaged with the clutch while being slid, compared with the case where the temperature is higher than the predetermined value. The predetermined range is reduced.

  The control apparatus for a hybrid vehicle is mounted on the hybrid vehicle and includes an engine, a first rotating electrical machine, a second rotating electrical machine, a power transmission mechanism, and control means. The power transmission mechanism includes a plurality of rotating elements that are differentially rotatable with respect to each other. Specifically, the power transmission mechanism includes a first rotating element coupled to the first rotating electrical machine, a second rotating element coupled to the second rotating electrical machine and the drive shaft via a clutch, and a first rotating element coupled to the engine. 3 rotation elements. Here, “connected” includes a structure that directly transmits power (rotation), and also includes a structure that indirectly transmits power via one or more members. The control means is, for example, an ECU (Electronic Control Unit), and when the travel mode is switched from the first travel mode to the second travel mode, the clutch is engaged while sliding. Here, the first travel mode is a travel mode when the clutch is in the released state, and indicates EV travel with the engine stopped. The second travel mode is a travel mode in which the clutch is engaged and the engine is driven. For example, the power output from the engine is divided into two parts, and a part of the drive power remains on the drive shaft with mechanical power. It is a series parallel running that outputs and outputs the remaining power to the drive shaft. Then, the control means changes the slip amount of the clutch according to the required driving force. The “clutch slip amount” corresponds to the amount of heat generated in the clutch when the clutch is in a slip state.

In general, the appropriate clutch slippage varies depending on the required driving force. For example, when the required driving force is large and a large torque is transmitted to the clutch in the slipping state of the clutch, the amount of slipping of the clutch at the time of engagement from the viewpoint of suppressing deterioration of the clutch due to heat generation and high responsiveness. It is desirable that there is little. On the other hand, when the required driving force is small, it is relatively easy for the user to feel a shock. Therefore, it is desirable that the clutch slip amount when engaged is large. In consideration of the above, the control device for the hybrid vehicle changes the slip amount of the clutch according to the required driving force. Thereby, the control apparatus of a hybrid vehicle can implement | achieve the improvement of a response, reduction of a shock, etc.
In addition, when the rotational speed difference between the engagement elements of the clutch is within a predetermined range, the control means engages the clutch while sliding, and the control means causes the temperature of the oil in the transmission to be smaller than the predetermined value. In this case, the predetermined range is made smaller than when the temperature is equal to or higher than a predetermined value. The above-mentioned predetermined value is determined in advance by experiments or the like based on, for example, whether or not a shock has occurred due to a decrease in clutch responsiveness. According to this aspect, the hybrid vehicle control device can reduce the shock at the time of clutch engagement even when the controllability of the clutch is low at a low oil temperature.

  In one aspect of the hybrid vehicle control device, the control means adjusts the slip amount of the clutch by changing a time width during which the clutch is slid according to a required driving force. Thereby, the control apparatus of a hybrid vehicle can adjust the slip amount of a clutch suitably, and can implement | achieve the improvement of a response, a reduction of a shock, etc.

In another aspect of the control apparatus of the hybrid vehicle, said control means sets the predetermined range according to the required driving force. In general, when the required driving force is large, high response is required, while the shock sensitivity of the user is relatively low. Therefore, the control apparatus of a hybrid vehicle can improve responsiveness, suppressing a shock by setting a predetermined range according to a request | requirement driving force.

  In another aspect of the hybrid vehicle control device, the control means increases the predetermined range when the required driving force is greater than a predetermined value, compared to when the required driving force is less than or equal to the predetermined value. . The predetermined value is determined in advance based on experiments or the like based on, for example, whether or not high response is necessary and shock sensitivity. By doing in this way, the control apparatus of a hybrid vehicle can improve responsiveness in the range which a shock is accept | permitted, when required drive force is large, such as at the time of WOT (Wide Open Throttle).

An example of the schematic block diagram of the hybrid vehicle which concerns on embodiment is shown. It is an example of the schematic block diagram of a hybrid drive device. It is an example of the map which shows the relationship between an accelerator opening and a clutch slip time width. It is an example of the flowchart which shows the process sequence which concerns on 1st Embodiment. It is an operation alignment chart which illustrates one operation state of a hybrid drive device. It is an example of the map which shows the relationship between an upper limit allowable rotation speed and an accelerator opening. It is an example of the flowchart which shows the process sequence which concerns on 2nd Embodiment.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Configuration of hybrid vehicle]
First, an example of the configuration of a hybrid vehicle 1 to which the hybrid vehicle control device according to the present invention is applied will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a hybrid vehicle 1. The hybrid vehicle 1 includes an ECU 100, a PCU (Power Control Unit) 11, a battery 12, an accelerator opening sensor 13, a vehicle speed sensor 14, an oil temperature sensor 16, and a hybrid drive device 10.

  The ECU 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an A / D (Analog to Digital) converter, an input / output interface, and the like. It is an electronic control unit for controlling. The ECU 100 executes control described later according to a control program stored in the ROM. The ECU 100 functions as a “control unit” in the present invention. Note that the physical, mechanical, and electrical configurations of the control means according to the present invention are not limited to this. For example, the control means includes a plurality of computers such as a plurality of ECUs, various processing units, various controllers, or a microcomputer device. It may be a system or the like.

  The hybrid drive device 10 drives the hybrid vehicle 1 by supplying driving torque as driving force to the left axle SFL (corresponding to the left front wheel FL) and the right axle SFR (corresponding to the right front wheel FR), which are the axles of the hybrid vehicle 1. Drive unit. The detailed configuration of the hybrid drive device 10 will be described later.

  The PCU 11 includes an inverter (not shown), and is a control unit that controls power input / output between the battery 12 and each motor generator described later, or power input / output between the motor generators not via the battery 12. is there. Specifically, the PCU 11 converts the DC power extracted from the battery 12 into AC power and supplies it to each motor generator, and converts the AC power generated by each motor generator into DC power and supplies it to the battery 12. To do. The PCU 11 is electrically connected to the ECU 100, and its operation is controlled by the ECU 100.

  The battery 12 is a battery unit that has a configuration in which a plurality of unit battery cells are connected in series and functions as a power supply source related to power for powering each motor generator.

  The accelerator opening sensor 13 is a sensor configured to be able to detect an accelerator opening “Ta” as an operation amount of an accelerator pedal (not shown) of the hybrid vehicle 1. The accelerator opening sensor 13 is electrically connected to the ECU 100, and the detected accelerator opening Ta is referred to by the ECU 100 at a constant or indefinite period.

  The vehicle speed sensor 14 is a sensor that detects the vehicle speed “V” of the hybrid vehicle 1. The vehicle speed sensor 14 is electrically connected to the ECU 100, and the detected vehicle speed V is referred to by the ECU 100 at a constant or indefinite period.

  The oil temperature sensor 16 is a sensor configured to be able to detect the oil temperature of the transmission in the hybrid drive device 10. The oil temperature sensor 16 outputs the detection result to the ECU 100 at a constant or indefinite period.

  The configuration of the hybrid vehicle 1 shown in FIG. 1 is an example, and the configuration to which the present invention can be applied is not limited to this. For example, the ECU 100 may estimate the oil temperature from the outside air temperature or the engine water temperature, for example, instead of the oil temperature sensor 16.

[Configuration of hybrid drive unit]
Here, the detailed configuration of the hybrid drive apparatus 10 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram of the hybrid drive device 10. In the figure, the same reference numerals are given to the same portions as those in FIG. 1, and the description thereof is omitted as appropriate.

  In FIG. 2, the hybrid drive device 10 is abbreviated as an engine 20, a power split mechanism 30, a motor generator MG1 (hereinafter abbreviated as “motor MG1” as appropriate), and a motor generator MG2 (hereinafter abbreviated as “motor MG2” as appropriate). ), An input shaft 40, a clutch CL, a brake BR, a speed reduction mechanism 60, and an oil pump 70.

  The engine 20 functions as a main power source of the hybrid vehicle 1. The engine torque “Te” that is the output power of the engine 20 is connected to the input shaft 40 of the hybrid drive device 10 via a crankshaft (not shown).

  The motor MG1 is a motor generator as an example of the “first rotating electrical machine” according to the present invention, which has a power running function that converts electrical energy into kinetic energy and a regeneration function that converts kinetic energy into electrical energy.

  The motor MG2 is a motor generator as an example of a “second rotating electrical machine” according to the present invention having a larger physique than the motor MG1, and, like the motor MG1, a power running function that converts electrical energy into kinetic energy, and kinetic energy And a regenerative function for converting the energy into electrical energy. Unlike motor MG1 and engine 20, motor MG2 operates its output torque (hereinafter referred to as “MG2 torque Tm”) on the drive shaft of hybrid vehicle 1 (hereinafter referred to as “drive shaft OUT”). It is possible to make it. Therefore, the motor MG2 can assist the travel of the hybrid vehicle 1 by applying torque to the drive shaft OUT, or can perform power regeneration by inputting the torque from the drive shaft OUT. The MG2 torque Tm is controlled by the ECU 100 through the PCU 11 together with the input / output torque of the motor MG1 (hereinafter referred to as “MG1 torque Tg”).

  The motor MG1 and the motor MG2 function as a synchronous motor generator, and include, for example, a rotor having a plurality of permanent magnets on the outer peripheral surface, and a stator wound with a three-phase coil that forms a rotating magnetic field.

  The power split mechanism 30 is a composite planetary gear mechanism that is an example of the “power transmission mechanism” according to the present invention. The power split mechanism 30 includes a sun gear S1 as an example of the “first rotating element” according to the present invention provided in the center portion, and a “second rotating element according to the present invention provided concentrically on the outer periphery of the sun gear S1. , A plurality of pinion gears (not shown) that are arranged between the sun gear S1 and the ring gear R1 and revolve around the outer periphery of the sun gear S1, and a book that supports the rotation shaft of each of the pinion gears. And a carrier C1 as an example of the “third rotating element” according to the invention.

  Here, the sun gear S1 is connected to the rotor of the motor MG1 so as to share the rotation axis, and the rotation speed is equivalent to the rotation speed of the motor MG1 (hereinafter referred to as “MG1 rotation speed Nmg1”). It is. Ring gear R1 is connected to reduction mechanism 60 via clutch CL. The clutch CL is, for example, a hydraulic control type or electromagnetic type clutch. The rotation speed of the ring gear R1 is equivalent to the rotation speed of the drive shaft OUT (hereinafter referred to as “output rotation speed Nout”) when the clutch CL is engaged. The carrier C1 is connected to an input shaft 40 connected to the crankshaft of the engine 20, and the rotation speed is equivalent to the rotation speed of the engine 20 (hereinafter referred to as “engine rotation speed Ne”).

  In the power split mechanism 30, the engine torque Te supplied from the engine 20 to the input shaft 40 under the above-described configuration is applied to the sun gear S1 and the ring gear R1 by the carrier C1 at a predetermined ratio, specifically, between each gear. Distribute at a ratio according to the gear ratio. That is, the power split mechanism 30 splits the power of the engine 20 into two systems.

  Reduction mechanism 60 is connected to the rotor of motor MG2 and is connected to ring gear R1 via clutch CL. The reduction mechanism 60 transmits the rotation of the drive shaft OUT to the motor MG2 in a form that is reduced in accordance with a reduction ratio that is determined according to the gear ratio of each gear that constitutes the reduction mechanism 60. Therefore, the rotational speed of motor MG2 (hereinafter referred to as “MG2 rotational speed Nmg2”) is uniquely determined according to vehicle speed V. Further, the speed reduction mechanism 60 includes a drive shaft OUT that exhibits a rotational state that is unambiguous with the axle, a reduction gear coupled to the drive shaft OUT, and a differential. The rotational speed of each axle is transmitted to the drive shaft OUT while being decelerated by the reduction mechanism 60 according to a predetermined gear ratio.

  The oil pump 70 supplies lubricating oil to each part of the hybrid drive device 10. The oil pump 70 is driven by the power transmitted by the input shaft 40.

  The configuration according to the embodiment relating to the “power transmission mechanism” according to the present invention is not limited to that of the power split mechanism 30. For example, the power transmission mechanism according to the present invention may be a composite planetary gear mechanism in which a plurality of planetary gear mechanisms are combined.

[Control method]
First, the control of the clutch CL executed by the ECU 100 will be described.

  When performing EV traveling, ECU 100 releases clutch CL, stops engine 20, and travels by motor MG2. Thus, ECU 100 suppresses losses due to dragging of the gears and bearings of motor MG1 and power split mechanism 30 during EV traveling by releasing clutch CL during EV traveling. The above-described EV traveling is an example of the “first traveling mode” in the present invention.

  On the other hand, the ECU 100 causes the hybrid vehicle 1 to function as a so-called series-parallel hybrid vehicle by engaging (engaging) the clutch CL and driving the engine 20. That is, in this case, the hybrid vehicle 1 divides the power from the engine 20 by the power split mechanism 30, outputs one of the power to the drive shaft OUT as mechanical power, and converts the remainder to electric power by the motors MG1 and MG2. And output to the drive shaft OUT. Hereinafter, this traveling state is also referred to as “series parallel traveling”. Series parallel traveling is an example of the “second traveling mode” in the present invention.

  Then, when switching from EV traveling to series parallel traveling, the ECU 100 causes the clutch CL to transition from the released state to the engaged state and starts the engine 20. At this time, the ECU 100 keeps the clutch CL in a slipping state that is an intermediate state (half-engaged state) between the engaged state and the released state for a predetermined time width (also referred to as “clutch slipping time width TCL”).

  Hereinafter, this specific control method will be described in the first to third embodiments.

  Hereinafter, the “clutch slip amount” corresponds to the amount of heat generated in the clutch CL in the slip state. Specifically, the differential rotational speed between the engagement elements RCL and OCL, the clutch slip time width TCL, This is an amount corresponding to the product of the force with which the combined elements RCL and OCL are pressed. As will be described later, the ECU 100 adjusts the clutch slip amount by controlling the clutch slip time width TCL.

<First Embodiment>
In the first embodiment, the ECU 100 changes the clutch slip time width TCL according to the required driving force. Specifically, the ECU 100 changes the clutch slip time width TCL based on the load state of the hybrid vehicle 1 (also simply referred to as “vehicle state”) such as the accelerator opening degree Ta and the climbing state.

  More specifically, ECU 100 has a large required driving force, and torque transmitted to engine 20 via clutch CL when engine 20 is started (also referred to as “engine start”) (also simply “transmission torque”). Is large, that is, when the force with which the engagement elements RCL and OCL press is large, the clutch slip time width TCL is shortened to prevent the clutch slip amount from increasing. As a result, the ECU 100 shortens the time required to engage the clutch CL to improve the responsiveness, and suppresses the friction material of the clutch CL from exceeding the allowable heat generation amount.

  Further, when the transmission torque at the time of starting the engine is small, that is, when the required driving force at the time of starting the engine is small, the ECU 100 increases the clutch slip time width TCL and increases the clutch slip amount. As described above, the ECU 100 suppresses the shock by increasing the clutch slip time width TCL in a situation where the transmission torque is small and the user can easily feel the shock caused by the engagement of the clutch CL.

  A method of setting the clutch slip time width TCL will be specifically described with reference to FIG. FIG. 3 is an example of a map showing the relationship between the accelerator opening degree Ta and the clutch slip time width TCL.

  As shown in FIG. 3, the ECU 100 shortens the clutch slip time width TCL as the accelerator opening degree Ta increases. Thereby, ECU100 can improve the responsiveness in the case where a high response is required. Further, the ECU 100 can suppress the heat generation of the friction material of the clutch CL and extend the life of the friction material. Further, the ECU 100 increases the clutch slip time width TCL as the accelerator opening degree Ta is smaller. Thereby, ECU100 can reduce the shock resulting from engagement of clutch CL when accelerator opening degree Ta is a low opening degree, and can improve drivability.

  In addition to or instead of the accelerator opening degree Ta, the ECU 100 determines the clutch slip time width TCL in accordance with the upward inclination angle of the traveling road (also simply referred to as “inclination angle Ang”). Specifically, when ECU 100 determines that the inclination angle Ang is large and the transmission torque increases, the ECU 100 sets the clutch slip time width TCL to be shorter than that when it is determined that the inclination angle Ang is small. In this case, for example, the ECU 100 estimates the inclination angle Ang by detecting the inclination of the hybrid vehicle 1 based on detection signals of various sensors such as a G sensor and an angular velocity sensor. Then, the ECU 100 determines the clutch slip time width TCL based on the inclination angle Ang by referring to a predetermined map or the like. The above-described map is a map of the inclination angle Ang and the clutch slip time width TCL, or a map of the inclination angle Ang, the accelerator opening degree Ta, and the clutch slip time width TCL. Are stored in advance in the memory.

(Processing flow)
FIG. 4 is an example of a flowchart showing a processing procedure executed by the ECU 100 in the first embodiment. The ECU 100 repeatedly executes the process of the flowchart shown in FIG. 4 according to a predetermined cycle.

  First, the ECU 100 determines whether or not there is a request for starting the engine 20 (step S101). That is, the ECU 100 determines whether or not the traveling mode is a traveling state in which the clutch CL is shifted to the engaged state from the EV traveling in which the clutch CL is in the released state and switched to the series parallel traveling. When it is determined that there is a request for starting the engine 20 (step S101; Yes), the ECU 100 determines whether or not it is possible to shift to start control of the engine 20 (step S102). Then, when ECU 100 determines that it is possible to shift to start control of engine 20 (step S102; Yes), the process proceeds to step S103.

  On the other hand, when the ECU 100 determines that there is no request for starting the engine 20 (step S101; No), or when it is determined that the engine 20 cannot be shifted to the start control (step S102; No), the processing of the flowchart is performed. finish.

  Next, the ECU 100 identifies the vehicle state (step S103). Specifically, the ECU 100 specifies the accelerator opening degree Ta based on the detection signal of the accelerator opening degree sensor 13. Further, the ECU 100 identifies the inclination angle Ang by detecting the inclination of the vehicle with respect to the horizontal direction using, for example, a G sensor or an angular velocity sensor. Then, ECU 100 determines a clutch slip time width TCL based on the vehicle state (step S104). The ECU 100 specifies the clutch slip time width TCL based on the accelerator opening degree Ta and the inclination angle Ang, for example, by referring to a predetermined map.

  Then, the ECU 100 keeps the clutch CL in the slipping state for the clutch slipping time width TCL determined in step S104 (step S105). At this time, the ECU 100 performs control to synchronize the rotation of the engagement elements RCL and OCL of the clutch CL (also referred to as “clutch rotation synchronization control”), and the absolute difference in rotational speed between the engagement elements RCL and OCL of the clutch CL. When the value (hereinafter also referred to as “differential rotation speed Nd”) becomes equal to or less than a predetermined value, the clutch CL is shifted from the released state to the slipped state.

  Next, the ECU 100 shifts the clutch CL to the engaged state (step S106). Specifically, the ECU 100 shifts the clutch CL from the slip state to the engaged state. Then, ECU 100 performs start control of engine 20 after engagement of clutch CL (step S107).

Second Embodiment
In the second embodiment, in addition to the first embodiment, when the required driving force is high, the ECU 100 increases the upper limit value (the “upper limit allowable rotation speed” of the differential rotation speed Nd for shifting the clutch CL from the disengaged state to the slipping state. Ndth ”) is increased. As a result, the ECU 100 shortens the time required to engage the clutch CL and improves the responsiveness. Hereinafter, the range of the differential rotation speed Nd for shifting the clutch CL from the disengaged state to the slipping state is also referred to as “allowable rotational speed region TNd”. The allowable rotation speed region TNd is an example of the “predetermined range” in the present invention.

  Here, the allowable rotation speed region TNd will be described with reference to a nomograph. FIG. 5 is an operation alignment chart illustrating one operation state of the hybrid drive device 10 during clutch rotation synchronization control. In FIG. 5, the vertical axis represents the rotational speed, and the horizontal axis, in order from the left, the sun gear S1 (uniquely, the motor MG1), the carrier C1 (uniquely, the engine 20), the engagement element RCL (uniquely). In particular, it represents the ring gear R1), the engagement element OCL (uniquely, the drive shaft OUT) and the motor MG2. Further, in FIG. 5, the power running torque of the motor MG1, the power running torque of the motor MG2, and the torque generated by the running resistance are indicated by arrows “Y1”, “Y2”, and “Y3”, respectively.

  Here, when the rotational speed of the engagement element OCL is based on the rotational speed of the engagement element RCL within the range indicated by the arrow “Y4”, the ECU 100 determines that the differential rotational speed Nd is within the allowable rotational speed range TNd. It is determined that Here, the range indicated by the arrow Y4 has a rotation speed obtained by adding the upper limit allowable rotation speed Ndth to the rotation speed of the engagement element OCL as an upper limit value, and subtracts the upper limit allowable rotation speed Ndth from the rotation speed of the engagement element OCL. The number of revolutions is a range with the lower limit. In other words, the range indicated by the arrow Y4 is that the rotation speed of the engagement element RCL corresponding to the operation state of the broken line “L3” is the lower limit value, and the rotation speed of the engagement element RCL corresponding to the operation state of the broken line “L4” is the upper limit. The range of values. Then, ECU 100 changes the width of arrow Y4 corresponding to allowable rotation speed region TNd according to the required driving force.

  Next, a specific method of setting the upper limit allowable rotational speed Ndth will be described with reference to FIG. FIG. 6 is an example of a map showing the relationship between the accelerator opening degree Ta and the upper limit allowable rotational speed Ndth. The above-described map is created in advance based on an experiment or the like, taking into account the allowable shock range, and stored in the memory.

  As shown in FIG. 6, the ECU 100 increases the upper limit allowable rotational speed Ndth as the accelerator opening degree Ta is larger, that is, as the required driving force is larger. In other words, the ECU 100 increases the upper limit allowable rotational speed Ndth and widens the allowable rotational speed region TNd in a situation where the required driving force is large and a shock is allowed. By doing in this way, ECU100 can shorten the time required for engagement of clutch CL, and can improve responsiveness, suppressing the fall of drivability by a shock.

  Here, the effect of the second embodiment will be supplementarily described. In the first embodiment, the ECU 100 sets the clutch slip time width TCL so as to maintain a balance between improvement in responsiveness and suppression of deterioration in drivability due to shock. On the other hand, the ECU 100 not only adjusts the clutch slip time width TCL described above, but also increases the tolerance rotational speed region TNd, thereby reducing the time required to engage the clutch CL and improving the responsiveness. Is possible. In particular, in a situation where the required driving force is large and shock is allowed, such as during WOT, the ECU 100 is required to engage the clutch CL without degrading drivability even if the allowable rotational speed region TNd is increased. It is possible to shorten the time.

  Considering the above, when the required driving force is large, the ECU 100 increases the upper limit allowable rotational speed Ndth and expands the allowable rotational speed region TNd. Thus, the ECU 100 can shorten the time required for engaging the clutch CL and improve the responsiveness.

(Processing flow)
FIG. 7 is an example of a flowchart showing a processing procedure executed by the ECU 100 in the second embodiment. ECU 100 repeatedly executes the processing of the flowchart shown in FIG. 7 according to a predetermined cycle.

  First, the ECU 100 determines whether or not there is a request for starting the engine 20 (step S201). When it is determined that there is a request for starting the engine 20 (step S201; Yes), the ECU 100 determines whether it is possible to shift to the start control of the engine 20 (step S202). If ECU 100 determines that the control can be shifted to the start control of engine 20 (step S202; Yes), the process proceeds to step S203.

  On the other hand, when the ECU 100 determines that there is no request for starting the engine 20 (step S201; No), or when it is determined that the engine 20 cannot be shifted to the start control (step S202; No), the processing of the flowchart is performed. finish.

  Next, the ECU 100 identifies the vehicle state (step S203). Specifically, the ECU 100 specifies the accelerator opening degree Ta and the inclination angle Ang based on detection signals from various sensors. Then, ECU 100 determines clutch slip time width TCL and also determines upper limit allowable rotation speed Ndth (step S204). At this time, the ECU 100 determines the upper limit allowable rotational speed Ndth from the accelerator opening degree Ta with reference to, for example, the map shown in FIG.

  Next, the ECU 100 determines whether or not the differential rotation speed Nd is equal to or lower than the upper limit allowable differential rotation speed Ndth (step S205). If the ECU 100 determines that the differential rotational speed Nd is equal to or lower than the upper limit allowable rotational speed Ndth (step S205; Yes), the ECU 100 keeps the clutch CL in the slipping state for the clutch sliding time width TCL (step S206). On the other hand, when the ECU 100 determines that the differential rotation speed Nd is larger than the upper limit allowable rotation speed Ndth (step S205; No), the ECU 100 performs clutch rotation synchronization control, and subsequently, in step S206, the differential rotation speed Nd becomes the upper limit allowable rotation speed. It is determined whether or not Ndth or less.

  Next, in step S207, the ECU 100 shifts the clutch CL to the engaged state (step S207). Then, ECU 100 performs start control of engine 20 after engagement of clutch CL (step S208).

<Third Embodiment>
In the third embodiment, in addition to or instead of the first embodiment and the second embodiment, the ECU 100 reduces the upper limit allowable rotational speed Ndth when the oil temperature is low and the accelerator opening degree Ta is small. . Thereby, ECU100 suppresses the shock at the time of engagement of clutch CL, and improves drivability.

  Generally, when the oil in the transmission is at a low oil temperature, the hydraulic response, that is, the controllability of the clutch CL is lowered. Therefore, in this case, a shock may occur when the clutch CL is engaged, and drivability may deteriorate.

  In consideration of the above, in the third embodiment, the ECU 100 takes into account the factors that cause variations in the responsiveness and controllability of the clutch CL such as the low oil temperature. Specifically, the ECU 100 determines that the upper limit allowable rotational speed is low when the accelerator opening degree Ta is low, when the oil temperature is low and the sensitivity at which the user feels shock is relatively high. Ndth is reduced, and the allowable rotational speed region TNd is reduced to the low rotational speed side. For example, the ECU 100 determines the upper limit allowable rotational speed Ndth with reference to a predetermined map or the like based on the oil temperature detected or estimated based on various sensors and the accelerator opening degree Ta. The above map is a map of the upper limit allowable rotational speed Ndth corresponding to the oil temperature and the accelerator opening degree Ta. For example, the map is prepared in advance based on experiments and the like in consideration of the response and controllability of the clutch CL. Is remembered. Thereby, ECU100 can suppress the shock at the time of engagement of clutch CL, and can improve drivability.

  Next, a processing procedure of the third embodiment will be described. In the third embodiment, the ECU 100 performs processing based on the flowchart of FIG. 7 as in the processing procedure of the second embodiment. In this case, the ECU 100 estimates or detects the oil temperature based on various sensors when specifying the vehicle state in step S203. In step S204, the ECU 100 determines the upper limit allowable rotational speed Ndth with reference to a predetermined map or the like based on the oil temperature and the accelerator opening degree Ta. As a result, the ECU 100 can appropriately determine the upper limit allowable rotational speed Ndth in consideration of factors that cause variations in the response and controllability of the clutch CL, and can suppress the occurrence of shock.

[Modification]
In the description of FIG. 6 of the second embodiment, the ECU 100 increases the upper limit allowable rotational speed Ndth and expands the allowable rotational speed region TNd as the accelerator opening degree Ta is larger, that is, as the required driving force is larger. However, the method to which the present invention is applicable is not limited to this.

  Instead, the ECU 100 increases the upper limit allowable rotational speed Ndth by a predetermined value or a predetermined rate when the required driving force or the accelerator opening degree Ta corresponding to the required driving force is larger than the predetermined threshold, as compared with other cases. May be. The above threshold is a threshold for determining whether or not high responsiveness is required, and is determined in advance based on, for example, experiments. Further, the predetermined value and the predetermined rate described above may be a variable determined according to the accelerator opening degree Ta or the like, or may be a predetermined constant. This also allows the ECU 100 to increase the allowable rotation speed region TNd when the required driving force is large, such as during WOT, to shorten the time required to engage the clutch CL, and to improve the responsiveness. .

  Similarly, in place of the description of the third embodiment described above, the ECU 100 reduces the upper limit allowable rotational speed Ndth by a predetermined value or a predetermined rate when the oil temperature is lower than a predetermined threshold value as compared with other cases. May be. The above threshold value is a threshold value for determining whether or not the responsiveness and controllability are lowered due to the low oil temperature, and is predetermined based on, for example, experiments. Also by this, ECU100 can suppress the shock at the time of engagement of clutch CL, and can improve drivability.

DESCRIPTION OF SYMBOLS 1 Hybrid vehicle 10 Hybrid drive device 12 Battery 20 Engine 30 Power split mechanism 40 Input shaft 60 Deceleration mechanism 100 ECU
MG1, MG2 Motor generator CL Clutch

Claims (4)

An engine,
A first rotating electrical machine;
A second rotating electrical machine;
A first rotating element connected to the first rotating electric machine, a second rotating element connected to the second rotating electric machine and a drive shaft via a clutch, and a third rotating element connected to the engine. A power transmission mechanism having a plurality of rotating elements capable of differential rotation with each other;
From the first traveling mode in which the clutch is disengaged and the engine is stopped and traveling by the second rotating electrical machine is changed to the second traveling mode in which the clutch is engaged and the engine is driven to travel. Control means for bringing the clutch into an engaged state while sliding when switching the running mode,
The control means changes the slip amount of the clutch according to the required driving force ,
When the rotational speed difference of the engagement element of the clutch is within a predetermined range, the control means engages the clutch while sliding,
The control device according to claim 1, wherein when the temperature of the oil in the transmission is lower than a predetermined value, the control means reduces the predetermined range compared to a case where the temperature is equal to or higher than the predetermined value .   2. The control device for a hybrid vehicle according to claim 1, wherein the control unit adjusts a slip amount of the clutch by changing a time width during which the clutch is slid according to a required driving force. Before SL control means, the control apparatus for a hybrid vehicle according to claim 1 or 2 sets the predetermined range according to the required driving force.   4. The control device for a hybrid vehicle according to claim 3, wherein when the required driving force is larger than a predetermined value, the control unit increases the predetermined range as compared with a case where the required driving force is equal to or less than the predetermined value.

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