JP2015196492A - Hybrid electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a distance by which a vehicle can be driven in reverse without entailing a reduction in driving force at a time of starting the vehicle by driving the vehicle in reverse in a parked state with a downward slope diagonally forward of the vehicle.SOLUTION: A vehicle is stopped after forward driving on a downhill road diagonally forward of the vehicle (S100 to S150). Subsequently, when a shift position SP is set to a P range (S160), a slop gradient Sgrad is calculated based on an acceleration G(x) in a vehicle front-rear direction and an acceleration G(y) in a vehicle right-left direction (S170). A target state of charge SOC* is set so as to become higher as the slope gradient Sgrad is greater (S180), and a battery 50 is forced to be charged until a state of charge SOC of the battery 50 is equal to the target state of charge SOC* (S190, S200). As a result, it is possible to increase a distance by which the vehicle can be driven in reverse without entailing a reduction in driving force when the shift position SP is subsequently set to an R range to start the vehicle by driving the vehicle in reverse.

Description

  The present invention relates to a hybrid vehicle, and more specifically, an engine, a generator that can generate electricity using power from the engine, a battery that can be charged by power generated by the generator, and reverse running using electric power from the battery. The present invention relates to a hybrid vehicle including an electric motor that can output a driving force for traveling.

  Conventionally, as this type of hybrid vehicle, one that makes it easy to start the engine when the shift position is a parking position or a reverse position has been proposed (for example, see Patent Document 1). In this hybrid vehicle, by such control, the battery is quickly charged by the generator at the parking position or the reverse drive position, and the battery storage ratio is prevented from decreasing.

  In addition, when traveling on a climbing gradient in the reverse direction, there has been proposed one that sets the charge / discharge required power so that the charging power becomes smaller as the climbing gradient increases (for example, see Patent Document 2). In this hybrid vehicle, by such control, the driving force in the forward direction that is output in association with the generation of charging electric power by the generator is reduced, so that the driving force during the reverse drive is increased.

  Further, there has been proposed a motoring of an engine in a state where fuel injection is stopped with a generator when traveling backward (see, for example, Patent Document 3). In this hybrid vehicle, by such control, the deficiency of the reverse drive force from the electric motor is compensated by the reverse drive force output accompanying the motoring of the engine.

Japanese Patent Laid-Open No. 11-122713 JP 2007-118918 A JP 2013-103593 A

  In the hybrid vehicle described above, when power is generated by the generator using the power from the engine, the driving force in the forward direction is output along with this power generation. Therefore, when traveling backward, basically only the power from the motor is used. Run. For this reason, when it is necessary to park in the downhill parking lot in front of the vehicle and start by reverse travel, a relatively long reverse travel with a large driving force is required. In the contents described in Patent Document 1 described above during reverse travel, the engine is started at an early stage and the battery is charged by the generator. However, this charging reduces the driving force for reverse travel, and reverse travel. Insufficient driving force is generated in traveling on a hill climbing direction. In addition, in the contents described in Patent Document 2, since the charging / discharging required power is set so that the charging power becomes smaller as the climbing gradient is larger, the shortage of the driving force can be alleviated slightly, and the shortage of the driving force can be reduced. It cannot be resolved. According to the contents described in Patent Document 3, deficiency in driving force can be resolved by motoring the engine by the generator, but since the power is consumed by motoring the engine by the generator, the distance that can be traveled backward is shortened. There is a case where the vehicle cannot travel backward for a distance required for starting from the parking lot. Some of these problems also apply to a hybrid vehicle that can generate power by a generator using power from the engine without output of driving force in the forward direction. In some cases, the vehicle can start in the forward direction even if it stops at a downward slope.

  The main object of the hybrid vehicle of the present invention is to increase the distance that the vehicle can travel backward without reducing the driving force when the vehicle is started by traveling backward from a vehicle having a downward slope when the vehicle is diagonally forward.

  The hybrid vehicle of the present invention employs the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An engine, a generator capable of generating electric power using the power from the engine, a battery that can be charged by the electric power generated by the generator, and a driving force for traveling including reverse traveling using the electric power from the battery In a hybrid vehicle equipped with a possible electric motor,
The battery is charged when the storage ratio of the battery is less than the target storage ratio calculated on the basis of the oblique slope state when the vehicle is parked in the parking range by tilting the vehicle forward in a downward slope. Control means for executing forced charging control for controlling the engine and the generator
It is characterized by that.

  In the hybrid vehicle according to the present invention, it is estimated that the vehicle starts to move backward when the vehicle is parked in a diagonally sloping state with a downward slope. Then, when the power storage ratio of the battery is less than the target power storage ratio calculated based on the oblique gradient state, forced charge control for controlling the engine and the generator is executed so that the battery is charged. Thereby, since the storage ratio of the battery is increased, the distance in which the vehicle can travel backward can be increased. In addition, since the timing for charging the battery is delayed, even in the case of a hybrid vehicle of the type that generates electric power by a generator using the power from the engine with the output of the driving force in the forward direction, the driving force at the time of reverse traveling is reduced. The timing to decrease can be delayed. As a result, it is possible to increase the distance in which the vehicle can travel backward without reducing the driving force when starting the vehicle by traveling backward.

  Here, the “diagonal gradient state” can be considered as a state in which the magnitude of the downward gradient in the vehicle longitudinal direction is larger than the first threshold value and the magnitude of the gradient in the vehicle lateral direction is larger than the second threshold value. Further, the “target power storage ratio” may be set in advance so as to increase as the square root of the sum of squares of the downward gradient in the vehicle front-rear direction and the gradient in the vehicle left-right direction increases. In this way, the larger the gradient in the oblique gradient state, the larger the target power storage ratio, and the longer the distance that can be traveled backward without decreasing the driving force even when the gradient is in the large oblique gradient state.

  In the hybrid vehicle of the present invention, when the shift position is set to the reverse position while the forced charging control is being performed, the control means has a storage ratio of the battery smaller than the target storage ratio. The forced charge control may be stopped when the value is equal to or greater than a predetermined control lower limit ratio, and the forced charge control may be continued when the battery storage ratio is less than the control lower limit ratio. In this way, it is possible to secure the driving force during reverse travel and to delay the timing for charging the battery during reverse travel.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 5 is a flowchart showing an example of a forced charge control routine executed by an HVECU 70. It is explanatory drawing which shows a mode that it stops ahead and parks in the parking lot which becomes diagonally downhill. It is explanatory drawing which shows an example of the map for charge target setting. It is explanatory drawing which shows an example of the relationship between the accumulation | storage ratio SOC of the climb start start by reverse drive, and the distance which can be climbed by reverse drive without a driving force fall.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the drawing, the hybrid vehicle 20 of the embodiment includes an engine 22 that outputs power using gasoline or light oil as a fuel, an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that controls the drive of the engine 22, an engine, and the like. A planetary gear 30 having a carrier connected to the crankshaft 26 and a ring gear connected to a drive shaft 36 connected to drive wheels 38a and 38b via a differential gear 37, and a rotor configured as a synchronous generator motor, for example. Motor MG1 connected to the sun gear of planetary gear 30, for example, a motor MG2 configured as a synchronous generator motor and having a rotor connected to drive shaft 36, inverters 41 and 42 for driving motors MG1 and MG2, Inverters 41 and 42 not shown A motor electronic control unit (hereinafter referred to as a motor ECU) 40 that drives and controls the motors MG1 and MG2 by switching the elements, and a motor MG1, configured as, for example, a lithium ion secondary battery via inverters 41 and 42. A battery 50 that exchanges power with the MG 2, a battery electronic control unit (hereinafter referred to as a battery ECU) 52 that manages the battery 50, and a hybrid electronic control unit (hereinafter referred to as a HVECU) 70 that controls the entire vehicle. Prepare.

  The engine ECU 24 receives signals from various sensors necessary for controlling the operation of the engine 22 via an input port, and the engine ECU 24 outputs various control signals for controlling the operation of the engine 22. It is output through the port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 of the engine 22.

  Signals from various sensors necessary to drive and control the motors MG1 and MG2 are input to the motor ECU 40 via an input port. The motor ECU 40 switches the inverters 41 and 42 to switching elements (not shown). A control signal or the like is output via the output port. The motor ECU 40 determines the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position detection sensor that detects the rotational positions of the rotors of the motors MG1, MG2. Arithmetic.

  The battery ECU 52 includes various sensors necessary for managing the battery 50, such as a battery voltage Vb from a voltage sensor 51a connected between terminals of the battery 50 and a current sensor 51b connected to a power line from the battery 50. The charge / discharge current Ib and the battery temperature Tb from the temperature sensor 51c attached to the battery 50 are input via the input port. In order to manage the battery 50, the battery ECU 52 is based on the integrated value of the charge / discharge current Ib of the battery 50 detected by the current sensor 51b, and the ratio of the capacity of power that can be discharged from the battery 50 at that time to the total capacity. A certain storage ratio SOC is calculated, or input / output limits Win and Wout, which are allowable input / output powers that may charge / discharge the battery 50, are calculated based on the calculated storage ratio SOC and the battery temperature Tb. .

  The HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening from the accelerator opening sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the acceleration G from the acceleration sensor 89, and the like are input via the input port. The HVECU 70 is communicably connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. In the hybrid vehicle 20 of the embodiment, the operation position of the shift lever 81 (shift position SP detected by the shift position sensor 82) includes a parking position (P range) used during parking, and a reverse position (R for reverse travel). Range), neutral position (N range), forward drive position (D range), etc.

  In the hybrid vehicle 20 of the embodiment configured in this way, during forward travel, the hybrid travel mode (HV travel mode) that travels with the operation of the engine 22 and the operation (fuel injection control, etc.) of the engine 22 are stopped. The vehicle travels in the electric travel mode (EV travel mode) and basically travels in the EV travel mode during reverse travel.

  When traveling in the HV traveling mode, the HVECU 70 sets a required torque Tr * (a positive value when traveling forward) required for traveling based on the accelerator opening Acc and the vehicle speed V. Subsequently, the set required torque Tr * is multiplied by the rotational speed Nr of the drive shaft 36 (for example, the rotational speed Nm2 of the motor MG2 (a positive value when traveling forward)) to obtain the traveling power Pdrv * required for traveling. The required power required for the vehicle is calculated by subtracting the calculated charge / discharge required power Pb * of the battery 50 based on the storage ratio SOC of the battery 50 (a positive value when discharging from the battery 50) from the calculated traveling power Pdrv *. Set Pe *. Then, the target rotational speed Ne * and the target torque Te * of the engine 22 are set using the required power Pe * and an operation line for efficiently operating the engine 22 (for example, an optimum fuel efficiency operation line). The torque command Tm1 * of the motor MG1 is set by the rotation speed feedback control so that the rotation speed Ne becomes the target rotation speed Ne *. Then, when the motor MG1 is driven with the torque command Tm1 *, the torque output from the motor MG1 and transmitted to the drive shaft 36 via the planetary gear 30 is subtracted from the required torque Tr * to calculate the temporary torque Tm2tmp of the motor MG2. The power consumption (generated power) of the motor MG1 obtained by multiplying the torque command Tm1 * of the motor MG1 by the rotational speed Nm1 is subtracted from the input / output limits Win and Wout of the battery 50 and further divided by the rotational speed Nm2 of the motor MG2. Torque limits Tm2min and Tm2max of the motor MG2 are calculated, and the temporary torque Tm2tmp is limited by the torque limits Tm2min and Tm2max and the positive and negative rated torques Tm2rat1 and Tm2rat2 to calculate the torque command Tm2 * of the motor MG2. Here, the rated torques Tm2rat1 and Tm2rat2 are set by applying the rotational speed Nm2 to a predetermined map for the relationship between the rotational speed Nm2 of the motor MG2 and the rated torques Tm2rat1 and Tm2rat2. Then, the target rotational speed Ne * and the target torque Te * are transmitted to the engine ECU 24, and the torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te *, controls the intake air amount, fuel injection control, and ignition of the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. Control and so on. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the plurality of switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  During travel in the EV travel mode, the HVECU 70 sets the required torque Tr * based on the accelerator opening Acc and the vehicle speed V, sets a value 0 to the torque command Tm1 * of the motor MG1, and travels in the HV mode. The torque command Tm2 * for the motor MG2 is set and transmitted to the motor ECU 40 in the same manner as described above. Then, the motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  Next, the operation of the hybrid vehicle 20 configured as described above, particularly the operation when the vehicle is stopped in a diagonally inclined state where the vehicle is obliquely forward and started by reverse traveling will be described. FIG. 2 is a flowchart showing an example of a forced charge control routine executed by the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every several tens of msec).

  When the forced charging control routine is executed, the HVECU 70 first determines whether or not the vehicle speed V is a value 0 and whether the shift position SP is in the R range (step S100), and the vehicle speed V is a value 0. If the shift position SP is not in the R range, a value 0 is set to the forward-facing stop determination flag A indicating whether or not the vehicle is parked forward on an oblique downhill road (step S110). The case where the vehicle speed V is not 0 and the shift position SP is not in the R range usually means that the vehicle is traveling in the D range. Therefore, the value 0 is set to the forward stop determination flag A on the oblique downhill road during traveling.

  On the other hand, when the vehicle speed V is 0 or the shift position SP is in the R range, whether or not the vehicle longitudinal acceleration G (x) is equal to or greater than the threshold Grad1 (step S120), the vehicle lateral acceleration G Whether or not the absolute value of (y) is greater than or equal to the threshold value Grad2 (step S130), whether or not the vehicle speed V (N) is 0 and the vehicle speed V (N-1) is greater than 0 (step S140). Determine. Here, the vehicle longitudinal acceleration G (x) and the vehicle lateral acceleration G (y) are the vehicle longitudinal acceleration and the vehicle lateral acceleration of the acceleration G from the acceleration sensor 89. The inside means the vehicle longitudinal component and the vehicle lateral component of the gravitational acceleration g. In the embodiment, the acceleration G (x) in the longitudinal direction of the vehicle has a positive acceleration as positive, and the acceleration G (y) in the lateral direction of the vehicle has a positive acceleration as right. The threshold value Grad1 and the threshold value Grad2 are determined in advance by experiments or the like as threshold values for determining a slope that is slanted downhill in the forward direction and that requires a relatively large driving force (torque) when starting by reverse travel. is there. Accordingly, the determinations in steps S120 and S130 are determinations as to whether or not the vehicle is on an oblique downhill road in the forward direction that requires a relatively large driving force (torque) when the vehicle starts traveling backward. N of the vehicle speed V (N) and the vehicle speed V (N−1) is a counter, and is incremented by 1 every time this routine is executed (see step S220). Accordingly, the vehicle speed V (N) is the vehicle speed V when this routine is executed this time, and the vehicle speed V (N-1) is the vehicle speed V when this routine is executed last time. From these things, determination of step S140 becomes determination of whether it stopped from forward run. Therefore, the determination in steps S120 to S140 is a determination as to whether or not the vehicle has stopped forward on an oblique downhill road in a forward direction that requires a relatively large driving force (torque) due to the start of reverse travel. When all of steps S120 to S140 are positively determined, that is, when the vehicle is started forward by a backward drive and stops forward on an oblique downhill in a forward direction that requires a relatively large driving force (torque), the forward stop determination flag A is displayed on the oblique downhill road. When the value 1 is set (step S150) and any one of steps S120 to S140 is a negative determination, the value at that time is held for the diagonally downhill forward stop determination flag A. If the stop is continued without changing the shift position SP after the value 1 is set in the diagonally downhill forward stop determination flag A, a negative determination is made in step S140, but the diagonally downhill forward stop determination flag A is a value. 1 is held.

  Thus, when the value 0 or the value 1 is set in the diagonally downhill forward stop determination flag A or the value at that time is held, the diagonally downward slope forward stop determination flag A is the value 1, and the shift position SP is P. It is determined whether or not the range is selected (step S160). The state of a vehicle that stops forward on an oblique downhill road is normally assumed to be a temporary stop or a change of traveling direction by turning back on a downhill, so that the shift position SP is set to the P range. There is no. Therefore, when the shift position SP is set to the P range after stopping forward on an oblique downhill road, as shown in FIG. 3, when parking is not possible due to forward obstacles due to obstacles such as walls. Is assumed. Therefore, the determination in step S160 means a determination as to whether or not there is a high possibility of starting by reverse travel after forward parking on an oblique downhill road. In addition, in the start by the reverse drive after the forward parking on the oblique downhill road, a relatively large driving force is required and the travel distance required for the reverse drive is also long.

  Consider the case where the shift position SP is set to the P range after the value 1 is set in the forward stop determination flag A on the oblique downhill road. At this time, the slope gradient Sgrad is calculated based on the vehicle longitudinal acceleration G (x) and the vehicle lateral acceleration G (y) (step S170), and the charging target SOC * is calculated based on the calculated slope gradient Sgrad. Set (step S180). The slope grade Sgrad can be obtained by solving the following equations (1) and (2). “G (z)” in Expression (1) is acceleration in the maximum tilt direction, and “g” in Expression (2) is gravity acceleration. In the embodiment, the charge target SOC * is determined in advance by storing the relationship between the slope gradient Sgrad and the charge target SOC * as a charge target setting map, and when the slope gradient Sgrad is given, the corresponding charge from the stored map is stored. It was set by deriving the target SOC *. An example of the charging target setting map is shown in FIG. As shown in the drawing, the charging target setting map is set such that the charging target SOC * increases as the slope gradient Sgrad increases.

G (z) = √ (G (x) ² + G (y) ² ) (1)
sin (Sgrad) = G (z) / g (2)

  When the charging target SOC * is thus set, the storage ratio SOC is compared with the charging target SOC * (step S190). When the storage ratio SOC is less than the target charge SOC *, the predetermined power Pchg for forced charging is set as the required power Pe *, and the target rotational speed Ne * of the engine 22 is set using the set required power Pe * and the operation line. And the target torque Te * are set, and the battery 50 is forcibly charged (step S200). For the forced charging of the battery 50, the HVECU 70 transmits the target rotational speed Ne * and the target torque Te * of the engine 22 to the engine ECU 24, and the engine 22 uses the target rotational speed Ne * and the target torque Te * of the engine 22 as a target. The torque command Tm1 * of the motor MG1 calculated so as to be operated at the rotational speed Ne * is transmitted to the motor ECU 40, and the engine ECU 24 having received the set value causes the engine 22 to be driven by the target rotational speed Ne * and the target torque Te *. The fuel injection control and the ignition control of the engine 22 are executed so as to operate at the operation point, and the motor ECU 40 performs the drive control of the motor MG1 with the torque command Tm1 *. On the other hand, when the storage ratio SOC is equal to or higher than the charge target SOC *, the operation of the engine 22 is stopped when the battery 50 is being forcibly charged (step S210). When the engine 22 is stopped, the HVECU 70 transmits a control signal for stopping the operation of the engine 22 to the engine ECU 24 and the motor ECU 40, and the engine ECU 24 that receives the control signal stops the fuel injection control and the ignition control to the engine 22. Then, it is executed by the motor ECU 40 stopping the drive control of the motor MG1. Thus, while the positive determination (A = 1 & SP = P range) continues in step S160, charging is performed until the storage ratio SOC of the battery 50 reaches the charging target SOC *.

  Subsequently, the counter N is incremented by 1 (step S220), and it is determined whether or not the shift position SP is in the R range (step S230). When the shift position SP is not in the R range, this routine ends. On the other hand, when the shift position SP is in the R range, it is determined whether or not the storage ratio SOC is less than the forcible charging start lower limit value Smin (step S240). Here, the forced charging start lower limit value Smin is set in advance as a power storage ratio SOC at which forced charging is started in a normal state such as when there is no gradient on the road surface. When the power storage rate SOC is less than the forced charging start lower limit Smin, the predetermined power Pchg for forced charging is set as the required power Pe *, and the target rotational speed of the engine 22 is set using the set required power Pe * and the operation line. Ne * and target torque Te * are set and the battery 50 is forcibly charged (step S250). This routine is terminated, and when the storage ratio SOC is equal to or greater than the forcible charging start lower limit value Smin, the battery 50 is forcibly charged. When charging is being performed, the operation of the engine 22 is stopped (step S260), and this routine is terminated.

  As shown in the middle vehicle of FIG. 3, consider a case where the vehicle travels as indicated by an arrow in a parking lot whose diagonally forward is a downhill road and stops, and then the shift position SP is set to the P range. When the vehicle is traveling as indicated by the arrow, the shift position SP is in the D range and the vehicle speed V is not 0. Therefore, in the forced charge control routine, an affirmative determination (V ≠ 0 & SP ≠ R range) in step S100. In step S110, a value 0 is set to the forward-facing stop determination flag A on the oblique downhill road. Since the forward stop determination flag A for the diagonal downhill road is 0 and the shift position SP is in the D range, a negative determination (A ≠ 1, SP ≠ P range) is made in step S160, and the counter N is incremented in step S220. In step S220, a negative determination (SP ≠ R range) is made, and the process ends. In other words, until the shift position SP stops in the D range, the process is ended only by setting the value 0 to the diagonally downhill forward stop determination flag A.

  If the vehicle stops with the shift position SP in the D range, a negative determination (V = 0) is made in step S100, the vehicle longitudinal acceleration G (x) is equal to or greater than the threshold Grad1, and the vehicle lateral direction When the absolute value of the acceleration G (y) is greater than or equal to the threshold value Grad2, a positive determination (V (N) = 0 & V (N-1)> 0) is also made in step S140. Is set to 1 (step S150). Since the diagonal downhill forward stop flag A is 1, but the shift position SP is in the D range, a negative determination (SP ≠ P range) is made in step S160, the counter N is incremented in step S220, and step S230. A negative determination (SP ≠ R range) is made and the process ends. When the acceleration G (x) in the longitudinal direction of the vehicle is less than the threshold value Grad1 or the absolute value of the acceleration G (y) in the lateral direction of the vehicle is less than the threshold value Grad2, the forward stop stop determination flag A having a value of 0 is held. In step S160, a negative determination (A ≠ 1, SP ≠ P range) is made. In step S220, the counter N is incremented. In step S220, a negative determination (SP ≠ R range) is made, and the process ends. To do. That is, when the vehicle stops with the shift position SP in the D range, the vehicle longitudinal acceleration G (x) is greater than or equal to the threshold Grad1 and the vehicle lateral acceleration G (y) is greater than or equal to the threshold Grad2. Only when there is a value 1 in the forward-facing stop determination flag A on the oblique downhill road.

  If the vehicle continues to stop while the shift position SP is in the D range, a negative determination (V = 0) is made in step S100, and a negative determination (V (N (V) N) is made in step S140 after the determination in steps S120 and S130. ) = 0 & V (N-1) = 0), and the forward-facing stop determination flag A on the diagonal downhill road is 1 but the shift position SP is in the D range, so a negative determination (A ≠ 1, SP in step S160). ≠ P range), the counter N is incremented in step S220, a negative determination (SP ≠ R range) is made in step S230, and the process ends. Accordingly, in this state, the diagonally downhill forward stop flag A having a value of 1 is held, and only the counter N is incremented.

  If the shift position SP is set to the P range after the value 1 is set in the forward-facing stop determination flag A on the oblique downhill road, a negative determination (V = 0) is made in step S100, and the steps after the determination in steps S120 and S130 are performed. After the negative determination (V (N) = 0 & V (N-1) = 0) is made in S140, the forward stop determination flag A on the diagonal downhill road is the value 1, and the shift position SP is in the P range. An affirmative determination is made in S160, a slope gradient Sgrad is calculated in step S170, and a charging target SOC * is set based on the slope Sgrad and the map in step S180. Subsequently, in step S190, the power storage rate SOC is compared with the charge target SOC *. When the power storage rate SOC is less than the charge target SOC *, the battery 50 is forcibly charged in step S200, and the power storage rate SOC is set to the charge target SOC *. In the above case, when the battery 50 is being forcibly charged in step S210, the operation of the engine 22 is stopped. Then, the counter N is incremented in step S220, a negative determination (SP ≠ R range) is made in step S230, and the process ends. Therefore, after the value 1 is set in the forward-facing stop determination flag A on the oblique downhill road, the shift position SP is set to the P range, and when this state is continued thereafter, the storage ratio SOC of the battery 50 reaches the charge target SOC *. Charging is performed.

  If the shift position SP is set to the R range after the battery 50 is forcibly charged until the storage rate SOC reaches the charge target SOC *, a negative determination (SP ≠) in step S160 after the processing of steps S100 to S150. P range) is made, the counter N is incremented in step S220, and a positive determination (SP = R range) is made in step S230. In step S240, it is determined whether or not the storage ratio SOC is less than the forced charge start lower limit value Smin. However, since the charge target SOC * is greater than the forced charge start lower limit value Smin, this determination is negative. After confirming that the operation of the engine 22 is stopped, the process is terminated. The hybrid vehicle 20 according to the embodiment, because of its structure, outputs a driving force in the forward direction when the battery 50 is forcibly charged. Therefore, when the vehicle 50 travels backward while performing the forced charging of the battery 50, the driving force for the reverse traveling is The driving force in the forward direction accompanying the forced charging of the battery 50 is subtracted from the driving force for backward traveling output from the motor MG2. However, if the battery 50 is forcibly charged until the storage ratio SOC reaches the charge target SOC * as in the forced charge control routine of the embodiment, the battery 50 is forced when the shift position SP is in the R range. Since charging is not performed, the vehicle can travel backward without a reduction in the driving force for backward traveling. FIG. 5 is an explanatory diagram showing an example of the relationship between the storage ratio SOC at the start of climbing by reverse travel and the distance that can be climbed by reverse travel without lowering the driving force. As shown in the figure, if the power storage rate SOC is larger than the forcible charging start lower limit value Smin, the greater the power storage rate SOC, the longer the distance that can be climbed by reverse travel without lowering the driving force. The charging target SOC * is set to a larger value as the slope gradient Sgrad is larger. If the battery 50 is forcibly charged until the power storage ratio SOC reaches the charging target SOC *, the reverse traveling is performed with a larger torque as the slope gradient Sgrad is larger. Even if the driving force does not decrease, the distance that can be climbed by reverse traveling becomes longer.

  If the shift position SP is set to the R range after the battery 50 is forcibly charged until the storage rate SOC reaches the charge target SOC *, a negative determination (SP ≠ P range) is made in step S160, and in step S220. The counter N is incremented, and an affirmative determination (SP = R range) is made in step S230. Then, in step S240, it is determined whether or not the power storage rate SOC is less than the forced charge start lower limit value Smin. When the power storage rate SOC is less than the forced charge start lower limit value Smin, the battery 50 is continuously charged (step S250). ) When the storage ratio SOC is less than the forced charging start lower limit value Smin, the forced charging of the battery 50 is terminated (step S260). During the forced charging of the battery 50, normally, the power storage rate SOC is often larger than the forced charging start lower limit value Smin, so that the forced charging of the battery 50 is terminated. Therefore, although the distance that can be climbed by reverse travel is shorter than when the battery 50 is forcibly charged until the storage rate SOC reaches the charge target SOC *, the reverse travel is performed without a decrease in the driving force of the reverse travel. can do.

  In the hybrid vehicle 20 of the embodiment described above, the acceleration G (x) in the vehicle front-rear direction is equal to or greater than the threshold Grad1 and the absolute value of the acceleration G (y) in the vehicle left-right direction is equal to or greater than the threshold Grad2 due to the vehicle traveling forward. When the vehicle stops diagonally in front on a downhill road and the shift position SP is set to the P range after that, the slope gradient Sgrad is calculated based on the vehicle longitudinal acceleration G (x) and the vehicle lateral acceleration G (y). At the same time, the charging target SOC * is set so as to increase as the slope gradient Sgrad increases, and the battery 50 is forcibly charged until the storage ratio SOC of the battery 50 reaches the charging target SOC *. As a result, when the shift position SP is set to the R range and the vehicle starts to move backward, the distance in which the vehicle can travel backward can be increased without reducing the driving force.

  In the present embodiment, the present invention is applied to the hybrid vehicle 20 of the embodiment that outputs driving force in the forward direction when the battery 50 is forcibly charged. A generator that can generate power using power from the engine, a battery that can be charged by power generated by the generator, and an electric motor that can output driving force for traveling including reverse traveling using the power from the battery, The present invention may be applied to any type of hybrid vehicle as long as it is provided.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to “engine”, the motor MG1 corresponds to “generator”, the battery 50 corresponds to “battery”, the motor MG2 corresponds to “motor”, the engine ECU 24 and the motor ECU 40 And HVECU 70 correspond to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of hybrid vehicles.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 50 Battery, 51a Voltage sensor, 51b Current sensor, 51c Temperature sensor, 52 Battery electronic control unit (Battery ECU), 70 Hybrid electronic control unit (HVECU), 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 accelerator pedal, 84 accelerator opening sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, 89 acceleration sensor MG1, MG2 motor.

Claims (1)

An engine, a generator capable of generating electric power using the power from the engine, a battery that can be charged by the electric power generated by the generator, and a driving force for traveling including reverse traveling using the electric power from the battery In a hybrid vehicle equipped with a possible electric motor,
The battery is charged when the storage ratio of the battery is less than the target storage ratio calculated on the basis of the oblique slope state when the vehicle is parked in the parking range by tilting the vehicle forward in a downward slope. Control means for executing forced charging control for controlling the engine and the generator
A hybrid vehicle characterized by that.

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