JP2013154718A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy both of power performance and energy-saving, in an engine start during travel of HEV.SOLUTION: A hybrid vehicle can travel by either of electric travel using only output of a second power generating electric motor MG2 and hybrid travel using output of the second power generating electric motor MG2 and an internal combustion engine 20. After a battery 64 is externally charged by use of a charger 102, the vehicle performs electric travel in an EV mode. At that time, if vehicle required power becomes an engine start power threshold or more and if vehicle speed becomes an engine start vehicle speed threshold or more, the vehicle is shifted to a hybrid travel state. If the battery 64 is externally charged and thereafter the electric travel in the EV mode continues, the engine start vehicle speed threshold is set to a high side threshold. After the internal combustion engine 20 is started at least once during electric travel in the EV mode after external charging, the engine start vehicle speed threshold is set to a low side threshold lower than a high side threshold.

Description

  The present invention relates to a hybrid vehicle equipped with an internal combustion engine and an electric motor as drive sources.

  One of the hybrid vehicles is a travel using only the output of the electric motor with the operation of the internal combustion engine stopped (hereinafter referred to as “electric travel”), and a travel using the output of both the internal combustion engine and the motor ( Hereinafter, it is referred to as “hybrid driving”. The hybrid vehicle is equipped with a power storage device (for example, a battery) that can supply electric power to the electric motor and can be charged.

  Furthermore, in recent years, hybrid vehicles (so-called “plug-in hybrid vehicles”) that can charge the power storage device with electric power supplied from outside the vehicle have been developed. Hereinafter, charging of the power storage device with electric power supplied from the outside of the vehicle is also referred to as “external charging”.

  When external charging is performed, the power storage device is often in a fully charged state, so the remaining capacity of the power storage device is large. Therefore, the hybrid vehicle gives priority to electric traveling over hybrid traveling after external charging. However, the hybrid vehicle operates the internal combustion engine when a large traveling driving force is required, such as during rapid acceleration or traveling uphill. More specifically, when the hybrid vehicle is in electric driving and the “required vehicle power that changes according to the accelerator operation amount and vehicle speed changed by the user” is equal to or greater than the “engine starting power threshold value”, Start (see, for example, Patent Document 1).

JP 2011-57115 A

  In addition, for the purpose of preventing the capacity of the power storage device from decreasing and protecting the electrical components, the hybrid vehicle starts the internal combustion engine and performs hybrid travel even when the vehicle speed exceeds the engine start vehicle speed threshold during electric travel. Migrate to

  By the way, a certain user drives the vehicle while changing the accelerator operation amount relatively gently, and another user drives the vehicle while changing the accelerator operation amount relatively frequently and violently. For example, as shown in FIG. 1B, a certain user drives the vehicle at the vehicle speed shown in FIG. 1A while changing the accelerator operation amount relatively gently. As shown in FIG. 1C, another user runs the vehicle at the vehicle speed shown in FIG. 1A while frequently and violently increasing and decreasing the accelerator operation amount.

  When electric travel is performed after external charging, if the accelerator operation amount is changed relatively gently, “the vehicle required power that changes according to the accelerator operation amount and the vehicle speed changed by the user” becomes “engine It is unlikely that the starting power threshold will be exceeded. Therefore, if the electric running is continued without starting the engine once after the external charging, it can be considered that the user has high expectation for the electric running. In other words, it can be considered that the user wants electric driving to continue. Therefore, in order to meet the expectation of such a user (a user who changes the accelerator operation amount gently), the engine start vehicle speed threshold described above is set to a high value so that the internal combustion engine is difficult to start. It is preferable.

  On the other hand, if the accelerator operation amount is suddenly increased during electric travel, the accelerator operation amount may become very large temporarily. In this case, since the vehicle required power is equal to or greater than the engine start power threshold, the internal combustion engine is started, and the hybrid vehicle changes the travel state from electric travel to hybrid travel.

  That is, it can be considered that a user who performs an accelerator operation for starting the engine during electric traveling desires driving with an emphasis on acceleration, and the user's expectation for electric driving is low. In other words, if the internal combustion engine has been started even once in a situation where electric driving is performed after external charging, it can be considered that the user is not likely to have a request to continue electric driving. .

  When such a user (a user who frequently changes the accelerator operation amount) is driving a hybrid vehicle, if the engine start vehicle speed threshold is set to a higher value, the accelerator operation amount is frequently and suddenly changed. However, the vehicle speed may be maintained at “a vehicle speed that is lower than the engine start vehicle speed threshold but relatively high”.

  FIG. 2 is a graph showing an example of the relationship between the current (battery current) IB from the power storage device and its time (duration) and the thermal allowable boundary of the electric components of the hybrid vehicle. A broken line L indicates the thermal tolerance boundary. As understood from the broken line L, as the battery current IB increases, the time during which the battery current IB can flow continuously decreases. That is, it is desirable that the “battery current IB and its duration” exist in the region on the origin side with respect to the broken line L so that the durability of the electrical component does not deteriorate for a sufficiently long period.

  Further, in FIG. 2, a line C <b> 1 indicates “the relationship between the battery current IB and its time (hereinafter, the“ current-time relationship ”) when the hybrid vehicle is operated at various vehicle speeds while changing the accelerator operation amount relatively gently. The line C2 indicates the “current-time relationship” when the hybrid vehicle is driven at various vehicle speeds while frequently changing the accelerator operation amount. The points Pv1 and Qv1 are current-time relationships when the vehicle speed is a value v1 (for example, 80 km / h). The point Pv2 and the point Qv2 are current-time relationships when the vehicle speed is “a value v2 higher than the value v1 (for example, 100 km / h)”.

  As can be understood from the point Pv1 and the point Qv1 in FIG. 2, when the vehicle speed is the value v1, the “current-time relationship” exists in the region on the origin side with respect to the broken line L regardless of how the accelerator operation amount changes. To do. On the other hand, as understood from the point Pv2 and the point Qv2, when the vehicle speed is the value v2, the “current-time relationship” when the accelerator operation amount is changed relatively gently is the origin side with respect to the broken line L. However, the “current-time relationship” in the case where the accelerator operation amount is frequently changed exists in a region opposite to the origin side with respect to the broken line L.

  Therefore, in order for the “current-time relationship” to be present in the region on the origin side with respect to the broken line L regardless of how the accelerator operation amount is changed, the vehicle speed becomes a vehicle speed in the vicinity of the value v2 or higher. In such a case, it is necessary to take measures such as lowering the upper limit of the instantaneous power Wout supplied from the power storage device to the electric motor. As a result, when the vehicle speed is the value v2, not only when the accelerator operation amount is frequently changed, but also by changing the accelerator operation amount that originally does not need to lower the upper limit of the instantaneous power Wout relatively gently. Even in such a case, the power of the electric motor tends to be insufficient, although it is slight.

  Therefore, when the engine start vehicle speed threshold is set to a constant value, it is possible to meet the demand of a user who expects electric travel and to ensure good drivability particularly when electric travel is performed at a high vehicle speed. difficult.

  In addition, FIG. 3 is a graph showing the relationship between the vehicle speed and the power consumption during electric travel. Here, the power consumption is the amount of power consumed when the hybrid vehicle travels a unit distance, and therefore the unit of the power consumption is Wh / km.

  As is clear from FIG. 3, the power consumption tends to deteriorate rapidly when the vehicle speed exceeds a certain high vehicle speed. That is, the power consumption when the vehicle speed is v2 is worse than the power consumption when the vehicle speed is v1. Therefore, from the viewpoint of power consumption, it is preferable to set the engine start vehicle speed threshold value between the value v1 and the value v2. However, if the engine start vehicle speed threshold value is set to a constant value in this way, it cannot meet the user's expectation of electric travel that changes the accelerator operation amount relatively gently.

The present invention has been made in view of the above-described problems.
The hybrid vehicle of the present invention is a vehicle equipped with an internal combustion engine and an electric motor as drive sources,
A power storage device capable of supplying electric power for driving the electric motor to the electric motor and being rechargeable;
An external charging unit that performs external charging for charging the power storage device by supplying electric power supplied from the outside of the hybrid vehicle to the power storage device;
A drive control unit;
Is provided.

The drive control unit
(A) When the “vehicle required power that changes according to the accelerator operation amount changed by the user and the vehicle speed” is smaller than the engine start power threshold and the vehicle speed is smaller than the engine start vehicle speed threshold, the internal combustion engine is operated Without controlling the electric motor based on the amount of accelerator operation, thereby causing the vehicle to run electrically while matching the power required for running the vehicle to the vehicle required power,
(B) When the vehicle required power becomes equal to or higher than the engine start power threshold during the electric running, and when the vehicle speed exceeds the engine start vehicle speed threshold, the internal combustion engine is operated and the electric motor and the internal combustion engine are operated. Is controlled based on the accelerator operation amount, thereby causing the vehicle to travel hybridly while making the power required for traveling the vehicle coincide with the vehicle required power.

Further, the drive control unit
The engine starting vehicle speed threshold is set to a high side threshold until the internal combustion engine is started after the external charging is performed, and the internal combustion engine is started after the external charging is performed. The engine starting vehicle speed threshold is set to a low threshold that is smaller than the high threshold.

  Since the internal combustion engine has never been started in the period after the external charging is performed and until the internal combustion engine is started, it is considered that the user's expectation for electric travel is high. Therefore, the present invention reduces the possibility that the vehicle speed exceeds the engine start vehicle speed threshold by setting the engine start vehicle speed threshold to the high side threshold as described above. As a result, it is possible to meet such user expectations.

  On the other hand, at the point in time after the external charging is performed and the internal combustion engine is started, it is considered that the user's expectation for electric driving is not high. Since it is highly likely that the user is a user who frequently and suddenly changes the operation amount, there is a possibility that the current-time relationship enters a region opposite to the origin side with respect to the broken line L in FIG. In addition, as understood from FIG. 3, if the engine start vehicle speed threshold value is set to the high side threshold value, the power consumption also deteriorates.

  Therefore, the present invention makes it easy to start the internal combustion engine by setting the engine start vehicle speed threshold value to the low side threshold value as described above. As a result, since the current required by the electric motor is reduced when the internal combustion engine is started, the current-time relationship is opposite to the origin side with respect to the broken line L in FIG. The possibility of entering the area can be reduced. Furthermore, since the power consumption is also improved, the fuel efficiency of the hybrid vehicle can be improved as a result.

  Other objects, other features and attendant advantages of the present invention will be readily understood from the description of the embodiments of the present invention described with reference to the following drawings.

FIG. 1 is a time chart showing a vehicle speed of a hybrid vehicle, an accelerator operation amount of a certain user, and an accelerator operation amount of another user. FIG. 2 is a graph showing an example of the relationship between the battery current and duration and the thermal tolerance boundary. FIG. 3 is a graph showing the relationship between vehicle speed and power consumption. FIG. 4 is a schematic diagram of a hybrid vehicle according to the embodiment of the present invention. FIG. 5 is a graph showing the contents of a table that defines the relationship between the accelerator operation amount and the vehicle speed, and the user request torque. FIG. 6 is a graph showing an engine start threshold of the hybrid vehicle shown in FIG. FIG. 7 is a graph showing an engine start threshold of the hybrid vehicle shown in FIG. FIG. 8 is a diagram for explaining the relationship between the remaining capacity of the power storage device and the EV mode and the HV mode. FIG. 9 is a flowchart showing a routine executed by the CPU (PMCPU) of the power management ECU of the hybrid vehicle shown in FIG. FIG. 10 is a flowchart showing a routine executed by the PMCPU of the hybrid vehicle shown in FIG. FIG. 11 is a flowchart showing a routine executed by PMCPU of the hybrid vehicle shown in FIG. FIG. 12 is a flowchart showing a routine executed by the PMCPU of the hybrid vehicle shown in FIG.

  Hereinafter, a vehicle according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 4, the vehicle 10 according to the embodiment of the present invention is a hybrid vehicle (plug-in hybrid vehicle). The vehicle 10 can travel in any one of “EV mode (first travel mode) and HV mode (second travel mode)” described later.

(Constitution)
The vehicle 10 includes a generator motor MG1, a generator motor MG2, an internal combustion engine 20, a power distribution mechanism 30, a power transmission mechanism 50, a first inverter 61, a second inverter 62, a boost converter 63, a battery 64 as a power storage device, and a combination meter 70. , A power management ECU 80, a battery ECU 81, a meter ECU 82, a motor ECU 83, an engine ECU 84, and the like.

  The ECU is an abbreviation for an electric control unit, and is an electronic control circuit having a microcomputer including a CPU, a ROM, a RAM, a backup RAM (or nonvolatile memory), an interface, and the like as main components. The backup RAM can hold data regardless of whether an ignition key switch (not shown) of the vehicle 10 is on or off.

  The generator motor (motor generator) MG1 is a synchronous generator motor that can function as both a generator and a motor. The generator motor MG1 is also referred to as a first generator motor MG1 for convenience. The first generator motor MG1 includes an output shaft (hereinafter also referred to as “first shaft”) 41.

  The generator motor (motor generator) MG2 is a synchronous generator motor that can function as either a generator or a motor, like the first generator motor MG1. The generator motor MG2 is also referred to as a second generator motor MG2 for convenience. The second generator motor MG2 includes an output shaft (hereinafter also referred to as “second shaft”) 42.

  The internal combustion engine (engine) 20 is a four-cycle / spark ignition / multi-cylinder / internal combustion engine. The engine 20 includes a known engine actuator 21. For example, the engine actuator 21 includes a fuel supply device including a fuel injection valve, an ignition device including an ignition plug, a throttle valve opening changing actuator, a variable intake valve control device (VVT), and the like. The engine 20 changes the intake air amount by changing the opening degree of a throttle valve disposed in an intake passage (not shown) by the throttle valve actuator, and changes the fuel injection amount according to the intake air amount. The torque generated by the engine 20 and the engine speed (accordingly, the engine output) can be changed. The engine 20 generates torque on a crankshaft 25 that is an output shaft of the engine 20.

  The power distribution mechanism 30 includes a known planetary gear device 31. The planetary gear device 31 includes a sun gear 32, a plurality of planetary gears 33, and a ring gear 34.

  The sun gear 32 is connected to the first shaft 41 of the first generator motor MG1. Accordingly, the first generator motor MG1 and the sun gear 32 are coupled so as to be able to transmit torque.

  Each of the plurality of planetary gears 33 meshes with the sun gear 32 and meshes with the ring gear 34. The planetary gear 33 has a rotation shaft (spinning shaft) provided on the planetary carrier 35. The planetary carrier 35 is held so as to be rotatable coaxially with the sun gear 32. Therefore, the planetary gear 33 can revolve while rotating on the outer periphery of the sun gear 32. The planetary carrier 35 is connected to the crankshaft 25 of the engine 20. Therefore, the planetary gear 33 can be rotationally driven by the torque input from the crankshaft 25 to the planetary carrier 35.

  The ring gear 34 is held so as to be rotatable coaxially with the sun gear 32.

  As described above, the planetary gear 33 meshes with the sun gear 32 and the ring gear 34. That is, the planetary gear 33 and the sun gear 32 are connected so as to be able to transmit torque. Further, the planetary gear 33 and the ring gear 34 are connected so as to be able to transmit torque.

  The ring gear 34 is connected to the second shaft 42 of the second generator motor MG2 via the ring gear carrier 36. Accordingly, the second generator motor MG2 and the ring gear 34 are coupled so as to be able to transmit torque.

  Further, the ring gear 34 is connected to an output gear 37 via a ring gear carrier 36. Therefore, the output gear 37 and the ring gear 34 are coupled so as to be able to transmit torque.

  The power transmission mechanism 50 includes a gear train 51, a differential gear 52, and a drive shaft (drive shaft) 53.

  The gear train 51 connects the output gear 37 and the differential gear 52 so that torque can be transmitted. The differential gear 52 is attached to the drive shaft 53. Drive wheels 54 are attached to both ends of the drive shaft 53. Accordingly, the torque from the output gear 37 is transmitted to the drive wheels 54 via the gear train 51, the differential gear 52, and the drive shaft 53. The vehicle 10 can travel by the torque transmitted to the drive wheels 54.

  As described above, the power distribution mechanism 30 and the power transmission mechanism 50 connect the internal combustion engine 20 and the drive shaft 53 so that torque can be transmitted, and the second generator motor MG2 and the drive shaft 53 can be connected so that torque can be transmitted. ing.

  The first inverter 61 is electrically connected to the first generator motor MG <b> 1 and the boost converter 63. Therefore, when the first generator motor MG1 is generating power, the electric power generated by the first generator motor MG1 is supplied to the battery 64 via the first inverter 61 and the boost converter 63. Conversely, the first generator motor MG1 is driven to rotate by the electric power supplied from the battery 64 via the boost converter 63 and the first inverter 61.

  The second inverter 62 is electrically connected to the second generator motor MG <b> 2 and the boost converter 63. Therefore, when the second generator motor MG2 is generating power, the electric power generated by the second generator motor MG2 is supplied to the battery 64 via the second inverter 62 and the boost converter 63. On the contrary, the second generator motor MG2 is driven to rotate by the electric power supplied from the battery 64 via the boost converter 63 and the second inverter 62.

  Furthermore, the electric power generated by the first generator motor MG1 can be directly supplied to the second generator motor MG2, and the electric power generated by the second generator motor MG2 can be directly supplied to the first generator motor MG1.

  The battery 64 is a power storage device, and is a lithium ion battery in this example. However, the battery 64 may be a power storage device that can be discharged and charged, and may be a nickel metal hydride battery or another secondary battery.

  The combination meter 70 includes a speed display 71, an electric travelable distance display (travelable distance display) 72, a remaining capacity display 73, an EV mode display lamp 74, and the like.

The speed indicator 71 is a display device that displays the speed (vehicle speed) of the hybrid vehicle 10.
The electric travelable distance indicator 72 is a display device for displaying the electric travelable distance.
The remaining capacity indicator 73 is a display device that displays information for indicating the remaining capacity SOC of the battery 64.
The EV mode display lamp 74 is turned on when the vehicle 10 is operated in the EV mode and is turned off when the vehicle 10 is operated in the HV mode.

  The power management ECU 80 (hereinafter referred to as “PMECU 80”) is connected to the battery ECU 81, the meter ECU 82, the motor ECU 83, the engine ECU 84, and the like so as to exchange information.

  The PM ECU 80 is connected to a power switch 91, a shift position sensor 92, an accelerator operation amount sensor 93, a brake switch 94, a vehicle speed sensor 95, an EV switch 96, and the like, and inputs output signals generated by these sensors. Yes.

  The power switch 91 is a system activation switch for the vehicle 10. When the power switch 91 is operated when a vehicle key (not shown) is inserted into the key slot and the brake pedal is depressed, the PM ECU 80 starts up the system, that is, a ready-on state (Ready-On state). It is comprised so that.

  The shift position sensor 92 generates a signal indicating a shift position selected by a shift lever (not shown) provided near the driver's seat of the vehicle 10 so as to be operable by the driver.

The accelerator operation amount sensor 93 generates an output signal representing an operation amount (accelerator operation amount AP) of an accelerator pedal (not shown) provided so as to be operable by the driver.
The brake switch 94 is in a state where the brake pedal is operated (that is, the brake device of the vehicle 10 is operated) when a brake pedal (not shown) that can be operated by the driver is operated. The output signal shown is generated.
The vehicle speed sensor 95 generates an output signal indicating the vehicle speed SPD of the vehicle 10.
The EV switch 96 is a manual switch that can be operated by a driver who desires to select and cancel the EV mode.

  The PM ECU 80 inputs “remaining capacity SOC (State Of Charge) of the battery 64” estimated and calculated by the battery ECU 81. The remaining capacity SOC is calculated according to a known method based on the integrated value of the current flowing into and out of the battery 64, the voltage of the battery 64, and the like. The remaining capacity SOC is defined as 100% dischargeable power when the battery 64 is new and fully charged, and 0% dischargeable power when the battery 64 is completely discharged. The ratio of the current dischargeable power of the battery 64 to the dischargeable power when 64 is new and fully charged is an amount expressed in “percentage (%)”. The remaining capacity SOC may be expressed by an absolute value of the remaining capacity (the unit is “Wh (watt hour)”).

  The PM ECU 80, via the motor ECU 83, signals representing the rotational speed of the first generator motor MG1 (hereinafter referred to as “first MG rotational speed Nm1”) and the rotational speed of the second generator motor MG2 (hereinafter referred to as “second MG”). A signal representing the rotation speed Nm2 ") is input.

  The first MG rotation speed Nm1 is calculated by the motor ECU 83 based on “an output value of the resolver 97 provided in the first generator motor MG1 and outputting an output value corresponding to the rotation angle of the rotor of the first generator motor MG1”. Yes. Similarly, the second MG rotation speed Nm2 is determined by the motor ECU 83 based on “the output value of the resolver 98 provided in the second generator motor MG2 and outputting an output value corresponding to the rotation angle of the rotor of the second generator motor MG2”. It has been calculated.

  The PM ECU 80 receives an output signal representing the engine state detected by the engine state quantity sensor 99 via the engine ECU 84. The output signal representing the engine state includes the engine speed Ne, the throttle valve opening degree TA, the engine coolant temperature THW, and the like.

  The PM ECU 80 is also connected to a charger 102 including an AC / DC converter, and sends an instruction signal to the charger 102. The charger 102 is connected to the inlet 101 via a power line. Further, the output power line of the charger 102 is connected between the boost converter 63 and the battery 64. The inlet 101 can be exposed on the side surface of the vehicle body, and is connected to a “power cable connected to an external power source” connector (not shown). When the power cable connector is connected to the inlet 101, the PM ECU 80 controls the charger 102, whereby the battery 64 is charged (externally charged) by the power supplied from the external power source through the power cable. Yes. That is, the charger 102 converts AC power from an external power source supplied to the inlet 101 into a predetermined DC voltage and supplies it to the battery 64.

  The battery ECU 81 monitors the state of the battery 64 and calculates the remaining capacity SOC as described above. Further, the battery ECU 81 estimates (calculates) the instantaneous output possible power Wout of the battery 64 according to a known method. The instantaneous output possible power Wout is a value that increases as the remaining capacity SOC increases.

  The meter ECU 82 sends instruction signals to the speed display 71, the electric travelable distance display 72, the remaining capacity display 73, the EV mode display lamp 74, and the like, and controls the display contents. ing.

  The motor ECU 83 is connected to the first inverter 61, the second inverter 62, and the boost converter 63, and sends an instruction signal to them based on a command from the PM ECU 80. Thus, the motor ECU 83 controls the first generator motor MG1 using the first inverter 61 and the boost converter 63, and controls the second generator motor MG2 using the second inverter 62 and the boost converter 63. It has become.

  The engine ECU 84 controls the engine 20 by sending an instruction signal to the engine actuator 21 based on a command from the PM ECU 80 and a signal from the engine state quantity sensor 99.

(Vehicle travel mode and engine operating conditions in EV mode)
Next, two traveling modes of the vehicle 10 will be described. One travel mode is the EV mode (first travel mode), and the other travel mode is the HV mode (second travel mode). These modes are well known and are described in, for example, Japanese Patent Application Laid-Open Nos. 2011-57115 and 2011-57116. Control of “the internal combustion engine 20, the first generator motor MG1 and the second generator motor MG2” corresponding to each mode is realized by the PM ECU 80 constituting the drive control unit.

  The EV mode is a mode in which the electric power supplied from the external power source and stored in the battery 64 is actively used for running the hybrid vehicle 10. The EV mode is also referred to as “CD (Charge Depleting) mode”. The EV mode is performed when the remaining capacity SOC is greater than the mode switching threshold SOCEV to HV after external charging. In the EV mode, unless the “EV mode engine start condition” described later is satisfied, the engine 20 is stopped and the hybrid vehicle 10 travels only by the output torque generated by the second generator motor MG2. That is, the hybrid vehicle 10 is electrically driven.

  The EV mode engine start condition described above includes a condition relating to a vehicle required power, which is a product of a torque (user required torque Tu) required by a user (driver) to travel the vehicle and a vehicle speed, and a condition relating to the vehicle speed. It consists of. The vehicle request power is also referred to as “user request output” or “vehicle request output”.

  The user request torque Tu is generally determined as shown in FIG. 5 based on the accelerator operation amount AP and the vehicle speed SPD. As is apparent from FIG. 5, when the accelerator operation amount AP is maintained at a constant value, the user request torque Tu is determined so as to decrease as the vehicle speed SPD increases.

  The EV mode engine start condition is related to the vehicle required power when the vehicle operating point determined by the user required torque Tu and the vehicle speed SPD is greater than the power threshold indicated by the line PW in FIG. It is established when the region on the opposite side of the origin with respect to the power threshold is entered, that is, when the power requirement is satisfied. The power threshold is determined corresponding to the instantaneous output possible power Wout of the battery 64. In other words, the power threshold is a value representing the relationship between the torque and the vehicle speed obtained when all of the electric power that can be supplied by the battery 64 is supplied to the second generator motor MG2. Therefore, the power threshold varies depending on the instantaneous power that the battery 64 can supply to the second generator motor MG2. When this power requirement is satisfied, the internal combustion engine 20 is started, and the output of the internal combustion engine 20 is supplemented by the output of the vehicle 10 which is insufficient only for the output of the second generator motor MG2.

  The power threshold value can also be represented by the relationship between the vehicle speed SPD and the power, as indicated by the line PW in FIG. 7, and is referred to as “power requirement output threshold value” for convenience.

  The EV mode engine start condition is related to the vehicle required power when the vehicle operating point determined by the user required torque Tu and the vehicle speed SPD is larger than the torque threshold indicated by the line TQ in FIG. This is also true when the region on the opposite side of the origin with respect to the torque threshold is entered, that is, when the torque requirement is satisfied. The torque threshold value is determined corresponding to the upper limit value of the torque output from the second generator motor MG2. The torque threshold is constant torque TQ1 when the vehicle speed SPD is equal to or less than “vehicle speed SPDth, which is the vehicle speed at the point where the torque threshold and the power threshold intersect” (actually, the predetermined vehicle speed SPD1 that is greater than the vehicle speed SPDth). . When the torque requirement is satisfied, the internal combustion engine 20 is operated, and the torque that is insufficient for the traveling of the vehicle 10 only by the output torque of the second generator motor MG2 is supplemented by the output torque of the internal combustion engine 20.

  The torque threshold value can also be expressed by the relationship between the vehicle speed SPD and the power, as indicated by the line TQ in FIG. 7, and is referred to as “torque requirement output threshold value” for convenience.

  As understood from the above, the EV mode engine start condition is determined by the engine start power threshold value Pegth indicated by the thick solid line Pegth in FIGS. Therefore, when the vehicle required output becomes equal to or higher than “the engine start power threshold Pegth indicated by the thick solid line in FIG. 7” during the electric travel, the internal combustion engine 20 is started and the hybrid vehicle 10 performs the hybrid travel.

  The condition relating to the vehicle speed SPD of the EV mode engine start condition is established when the vehicle SPD is equal to or higher than the engine start vehicle speed threshold value SPPDlmmt.

  Therefore, when the vehicle 10 is electrically driven in the EV mode, the vehicle required power Pv is equal to or greater than the “engine starting power threshold Pegth which is the smaller of the torque requirement output threshold and the power requirement output threshold”, or When the vehicle SPD becomes equal to or greater than the engine start vehicle speed threshold value SPPDuplmt, the vehicle 10 starts the internal combustion engine 20 and starts hybrid travel using the outputs of both the internal combustion engine 20 and the second generator motor MG2.

  The HV mode is a mode in which the output torque of the second generator motor MG2 generated by using the electric power of the battery 64 and the output torque of the engine 20 generated by operating the engine 20 are used for traveling of the vehicle 10. .

  Further, in the HV mode, the internal combustion engine 20 and the first generator motor MG1 are controlled so that the remaining capacity SOC approaches the target remaining capacity, and the battery 64 is charged by the energy generated by the internal combustion engine 20. In other words, since the HV mode is a mode for maintaining the energy (that is, the remaining capacity) of the power storage device, it is also referred to as a “CS (Charge Sustaining) mode”. However, even in the HV mode, when the engine 20 cannot be operated efficiently because the user request torque is small, and / or the remaining capacity SOC becomes larger than the target remaining capacity by a predetermined value or more, and the battery 64 is charged. When it is not necessary, the vehicle 10 temporarily stops the operation of the engine 20 and may travel only by the output torque generated by the second generator motor MG2.

  Note that the control contents of the first generator motor MG1, the second generator motor MG2, and the internal combustion engine 20 are disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2009-126450 (US Published Patent No. US2010 / 0241297) and Japanese Unexamined Patent Application Publication No. 9-308012. (US Patent No. 6,131,680 filed on March 10, 1997) and the like. These are incorporated herein by reference.

  When the battery 64 is externally charged and the remaining capacity SOC is equal to or higher than the mode switching threshold SOCEVtoHV shown in FIG. 8 in the ready-on state after the external charging, the hybrid vehicle 10 indicates that “the remaining capacity SOC is equal to or lower than the mode switching threshold SOCEVtoHV. To EV "mode.

  Once remaining capacity SOC falls below mode switching threshold SOCEV to HV, hybrid vehicle 10 is operated in the HV mode. In a state where the hybrid vehicle 10 is operated in the HV mode, for example, when driving on a downhill road, regenerative control is performed, whereby the remaining capacity SOC is “a first predetermined value SOC1 greater than the mode switching threshold SOCEVtoHV”. When the vehicle recovers to, the hybrid vehicle 10 is automatically driven in the EV mode. Further, when the remaining capacity SOC recovers to “second predetermined value SOC2 larger than mode switching threshold SOCEV to HV and smaller than first predetermined value SOC1” or more, the driver performs a predetermined operation on EV switch 96. As a result, the hybrid vehicle 10 is driven in the EV mode. These “conditions for permitting the EV mode” are also collectively referred to as “EV mode permission conditions”.

  In addition, when the hybrid vehicle 10 is traveling in the EV mode, when the driver performs a predetermined operation on the EV switch 96, the hybrid vehicle 10 is driven in the HV mode.

  Thus, the EV mode is a mode that is executed when the remaining capacity is greater than the mode switching threshold after external charging (when the remaining capacity SOC is greater than the mode switching threshold SOCEV to HV). “The first driving state (that is, electric driving) in which all of the driving force of the vehicle 10 is generated from the second generator motor MG2 by driving the second generator motor MG2 without driving” is “the internal combustion engine 20 is driven. At the same time, by driving the second generator motor MG2, the vehicle 10 is prioritized over the “second driving state in which the driving force of the vehicle 10 is generated from both the internal combustion engine 20 and the second generator motor MG2 (ie, hybrid travel)”. This is a mode for running.

  The HV mode is a mode that is executed when the remaining capacity becomes smaller than the mode switching threshold during EV mode traveling (when the remaining capacity SOC becomes smaller than the mode switching threshold SOCEVtoHV) or the like. Compared to the first driving state, the second driving state is given priority over the first driving state, and the vehicle 10 is driven.

(Actual operation)
Next, the operation of this embodiment will be described.

Setting of the engine start history flag Xrireki The CPU of the PM ECU 80 (hereinafter referred to as “CPU”) executes the “engine start history acquisition routine” shown in the flowchart of FIG. 9 every time a predetermined time elapses. It has become. Therefore, the CPU starts the process from step 900 in FIG. 9 at an appropriate timing, and proceeds to step 910 to determine “whether or not the current time is external charging”. That is, the CPU determines whether or not the power line connector is connected to the inlet 101 and power is being supplied from the power supply external to the hybrid vehicle 10 to the battery 64 (whether or not plug-in charging is in progress). judge.

  When the current time is during external charging, the CPU makes a “Yes” determination at step 910 to proceed to step 920 and calls the engine start history flag Xrireki during EV mode traveling (hereinafter referred to as “engine start history flag Xrireki”). ) Is set to “0”, and then the process proceeds to Step 930. On the other hand, if the current time is not during external charging, the CPU makes a “No” determination at 910 to directly proceed to step 930.

  In step 930, the CPU determines whether or not the internal combustion engine 20 has been started during traveling in the EV mode. The internal combustion engine 20 is started when the aforementioned EV mode engine start condition is satisfied when the hybrid vehicle 10 is traveling in the EV mode. As will be described later, the engine start vehicle speed threshold SPDuplmt is set to the high threshold SPDHi when the value of the engine start history flag Xrireki is “0”, and when the value of the engine start history flag Xrireki is “1”. The low side threshold value SPDLo is set. The low side threshold value SPDLo is smaller than the high side threshold value SPPDHi.

  If the internal combustion engine 20 has been started while traveling in the EV mode, the CPU makes a “Yes” determination at step 930 to proceed to step 940 to set the value of the engine start history flag Xrireki to “1”. Thereafter, the CPU proceeds to step 995 to end the present routine tentatively. On the other hand, if the internal combustion engine 20 has not been started during traveling in the EV mode, the CPU makes a “No” determination at step 930 to directly proceed to step 995 to end the present routine tentatively.

  As described above, the value of the engine start history flag Xrireki is set to “0” when external charging is performed, and is set to “1” when the internal combustion engine 20 is started even once thereafter. That is, the value of the engine start history flag Xrireki indicates the engine start history after the latest external charging.

Setting of engine start vehicle speed threshold value The CPU executes the “engine start vehicle speed threshold value setting routine” shown in the flowchart of FIG. 10 every time a predetermined time elapses. Accordingly, the CPU starts the process from step 1000 in FIG. 10 at an appropriate timing, and proceeds to step 1010 to determine “whether or not the hybrid vehicle 10 is currently traveling in the EV mode”.

  When the current mode is the EV mode (that is, when the hybrid vehicle 10 is currently traveling in the EV mode), the CPU makes a “Yes” determination at step 1010 to proceed to step 1020, and the engine start history It is determined whether or not the value of the flag Xrireki is “1”.

  If the value of the engine start history flag Xrireki is not “1”, the CPU makes a “No” determination at step 1020 to proceed to step 1030, and sets the engine start vehicle speed threshold SPDuplmt to “high side threshold SPDHi”. Thereafter, the CPU proceeds to step 1095 to end the present routine tentatively.

  On the other hand, if the value of the engine start history flag Xrireki is “1”, the CPU makes a “Yes” determination at step 1020 to proceed to step 1040 to set the engine start vehicle speed threshold value SPDuplmt to “higher than the threshold value SPHi”. Set to “small low-side threshold SPDLo”. Thereafter, the CPU proceeds to step 1095 to end the present routine tentatively.

  If the current mode is not the EV mode at the time when the CPU executes the process of step 1010 (that is, if the hybrid vehicle 10 is traveling in the HV mode at the current time), the CPU proceeds to step 1010. It determines with "No" and progresses to step 1050, and sets the value of engine starting vehicle speed threshold value SPDuplmt to HV mode vehicle speed threshold value SPDhv. Thereafter, the CPU proceeds to step 1095 to end the present routine tentatively.

Setting of the engine start vehicle speed threshold value The CPU executes the “EV mode permission flag XEV setting routine” shown in the flowchart of FIG. 11 every time a predetermined time elapses. Therefore, the CPU starts processing from step 1100 in FIG. 11 at an appropriate timing, and proceeds to step 1110 to determine whether or not “current time is ready-on state immediately after external charging is finished”.

  If the current state is the ready-on state immediately after the external charging is finished, the CPU regards the remaining capacity SOC as the mode switching threshold SOCEV to HV, determines “Yes” in step 1110, proceeds to step 1120, and permits the EV mode. The value of the flag XEV is set to “1”. Thereafter, the CPU proceeds to step 1130. On the other hand, if the current time is not the ready-on state immediately after finishing the external charging, the CPU makes a “No” determination at step 1110 to proceed directly to step 1130. The CPU also sets the value of the EV mode permission flag XEV to “1” even when the above-described EV mode permission condition is satisfied.

  In step 1130, the CPU determines whether or not the value of the EV mode permission flag XEV is “1”. If the value of the EV mode permission flag XEV is not “1”, the CPU makes a “No” determination at step 1130 to directly proceed to step 1195 to end the present routine tentatively.

  On the other hand, if the value of the EV mode permission flag XEV is “1”, the CPU makes a “Yes” determination at step 1130 to proceed to step 1140 to determine whether the remaining capacity SOC is equal to or less than the mode switching threshold SOCEVtoHV. Determine whether. If the remaining capacity SOC is not less than or equal to the mode switching threshold SOCEV to HV, the CPU makes a “No” determination at step 1140 to directly proceed to step 1195 to end the present routine tentatively.

  On the other hand, if the remaining capacity SOC is equal to or less than the mode switching threshold SOCEV to HV at the time when the CPU executes the process of step 1140, the CPU makes a “Yes” determination at step 1140 to proceed to step 1150 to allow EV mode permission. The value of the flag XEV is set to “0”. Thereafter, the CPU proceeds to step 1195 to end the present routine tentatively.

EV mode control The CPU executes the “EV mode control routine” shown in the flowchart of FIG. 12 every time a predetermined time elapses. Therefore, the CPU starts processing from step 1200 in FIG. 12 at an appropriate timing, and proceeds to step 1210 to determine whether or not the value of the EV mode permission flag XEV is “1”. If the value of the EV mode permission flag XEV is not “1”, the CPU makes a “No” determination at step 1210 to directly proceed to step 1295 to end the present routine tentatively. In this case, the CPU executes an HV mode control routine (not shown) and causes the hybrid vehicle 10 to travel in the HV mode.

  On the other hand, if the value of the EV mode permission flag XEV is “1”, the CPU makes a “Yes” determination at step 1210 to proceed to step 1220, and the lookup table MapTu (AP, SPD shown in FIG. ) To obtain the user request torque Tu by applying the actual “accelerator operation amount AP and vehicle speed SPD”. Next, the CPU proceeds to step 1230 to acquire the vehicle request power Pv (user request output Pu) by multiplying the user request torque Tu by the vehicle speed SPD.

  Next, the CPU proceeds to step 1240 to determine whether or not the vehicle required power Pv is equal to or greater than the engine start power threshold value Pegth shown in FIG. If vehicle required power Pv is equal to or greater than engine start power threshold value Pegth, the CPU makes a “Yes” determination at step 1240 to proceed to step 1260.

  On the other hand, if the vehicle required power Pv is not equal to or greater than the engine start power threshold value Pegth, the CPU makes a “No” determination at step 1240 to proceed to step 1250 to determine whether the vehicle speed SPD is equal to or greater than the engine start vehicle speed threshold value SPDuplmt. Determine whether. The engine start vehicle speed threshold SPDuplmt is set to the high threshold SPDHi or the low threshold SPDLo by the routine shown in FIG. At this time, if the vehicle speed SPD is equal to or greater than the engine start vehicle speed threshold SPDuplmt, the CPU makes a “Yes” determination at step 1250 to proceed to step 1260.

  On the other hand, if the vehicle speed SPD is not equal to or higher than the engine start vehicle speed threshold value SPDuplmt, the CPU makes a “No” determination at step 1250 to proceed to step 1290 to control the second generator motor MG2 so as to satisfy the vehicle required power Pv. To do. As a result, the hybrid vehicle 10 travels using only the output of the second generator motor MG2 (ie, electric travel).

  On the other hand, when the CPU proceeds to step 1260, the CPU determines whether or not the internal combustion engine 20 is stopped (operation) in step 1260. If the internal combustion engine 20 has stopped operating, the CPU makes a “Yes” determination at step 1260 to proceed to step 1270 to start the internal combustion engine 20 and then proceed to step 1280. On the other hand, if the internal combustion engine 20 is in operation at the time when the CPU executes the process of step 1260, the CPU makes a “No” determination at step 1260 to directly proceed to step 1280.

  When the CPU proceeds to step 1280, the CPU controls “the internal combustion engine 20 and the second generator motor MG2” so as to satisfy the vehicle required power Pv. As a result, the hybrid vehicle 10 travels using only the outputs of both the internal combustion engine 20 and the second generator motor MG2 (ie, hybrid travel). Thereafter, the CPU proceeds to step 1295 to end the present routine tentatively.

As described above, the hybrid vehicle 10 according to the embodiment of the present invention is
A battery 64 as a power storage device capable of supplying power for driving the second generator motor MG2 to the second generator motor MG2 and being rechargeable;
An external charging unit (power management ECU 80, charger 102, inlet 101, etc.) for charging (externally charging) the battery 64 by supplying electric power supplied from the outside of the hybrid vehicle 10 to the battery 64;
A drive control unit;
Is provided.

The drive control unit
(1) The vehicle required power (Pv = Tu · SPD = MapTu (AP, SPD) · SPD) that changes according to the accelerator operation amount AP and the vehicle speed SPD changed by the user is smaller than the engine start power threshold value Pegth ( If the vehicle speed SPD is smaller than the engine start vehicle speed threshold value SPDuplmt (see the determination of “No” in step 1250 of FIG. 12). The vehicle 10 is caused to travel by controlling the second generator motor MG2 based on the “user required torque Tu or vehicle required power Pv that changes according to the accelerator operation amount AP” without operating the internal combustion engine 20. The vehicle 10 is electrically driven while matching the power to the vehicle required power (see step 1290 in FIG. 12).
(2) When the vehicle required power Pv becomes equal to or greater than the engine start power threshold value Pegth during electric travel (see the determination of “Yes” in step 1240 in FIG. 12), and the vehicle speed SPD is the engine start vehicle speed threshold value. If SPDuplmt or more (see the determination of “Yes” in step 1250 in FIG. 12), the internal combustion engine 20 is operated, and the second generator motor MG2 and the internal combustion engine 20 are operated according to the accelerator operation amount AP. The vehicle 10 is hybrid-driven while the power required for running the vehicle 10 is matched with the vehicle required power Pv by performing control based on the user-requested torque Tu or the vehicle required power Pv that changes (step 1280 in FIG. 12 See).

Further, the drive control unit
Until the time when the internal combustion engine is started after external charging is performed (that is, when the value of the engine start history flag Xrireki is “0”, refer to the routine of FIG. 9), the engine start vehicle speed threshold value SPDuplmt is increased. Is set to the side threshold value SPHi (see step 1020 and step 1030 in FIG. 10), and from the time when the internal combustion engine 20 is started after the external charging is performed (that is, the value of the engine start history flag Xrireki is When “1” is set, refer to the routine of FIG. 9), and the engine start vehicle speed threshold value SPPDuplmt is set to “a low side threshold value SPDLo smaller than the high side threshold value SPHi” (Steps 1020 and 1040 of FIG. 10 are set). reference.).

  Therefore, it is possible to meet the demands of users who expect electric running, to improve the durability of electric parts and the like, and to improve the power consumption and the fuel consumption of the hybrid vehicle.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in step 1110 of FIG. 11, the CPU may determine “whether or not the current state is the ready-on state immediately after the external charging is finished and the remaining capacity SOC is larger than the mode switching threshold SOCEV to HV”.

 DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 20 ... Internal combustion engine, 30 ... Power distribution mechanism, 31 ... Planetary gear apparatus, 37 ... Output gear, 50 ... Power transmission mechanism, 52 ... Differential gear, 53 ... Drive shaft, 64 ... Battery (power storage device) , 70 ... Combination meter, 95 ... Vehicle speed sensor, 101 ... Inlet, 102 ... Charger, MG1 ... First generator motor, MG2 ... Second generator motor.

Claims (1)

A hybrid vehicle equipped with an internal combustion engine and an electric motor as drive sources,
A power storage device capable of supplying electric power for driving the electric motor to the electric motor and being rechargeable;
An external charging unit that performs external charging for charging the power storage device by supplying electric power supplied from the outside of the hybrid vehicle to the power storage device;
The electric motor without operating the internal combustion engine when the required vehicle power that changes according to the accelerator operation amount and the vehicle speed changed by the user is smaller than the engine start power threshold and the vehicle speed is smaller than the engine start vehicle speed threshold. Is controlled based on the accelerator operation amount so that the power required for running the vehicle coincides with the vehicle required power while the vehicle is electrically driven, and the vehicle required power is the engine start power during the electric travel. The vehicle is driven by operating the internal combustion engine and controlling the electric motor and the internal combustion engine based on the accelerator operation amount when the vehicle speed exceeds a threshold value and when the vehicle speed exceeds the engine start vehicle speed threshold value. The vehicle travels in a hybrid manner while matching the power required for the vehicle to the vehicle required power. A drive control unit that,
In a hybrid vehicle comprising:
The drive control unit
The engine starting vehicle speed threshold is set to a high side threshold until the internal combustion engine is started after the external charging is performed, and the internal combustion engine is started after the external charging is performed. A hybrid vehicle configured to set an engine start vehicle speed threshold value to a low-side threshold value that is smaller than the high-side threshold value.

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