JP2010167959A - Hybrid vehicle and engine control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle which reliably cancels engine torque reaction force to be transmitted to tires (driving wheels) at the time of power generation during stop. <P>SOLUTION: The hybrid vehicle is configured to transmit a driving force of an engine 1 to a generator 3 through a planetary gear mechanism 4. The hybrid vehicle transmits the engine torque reaction force which is the reaction force of the driving force of the power generating torque of the engine 1 transmitted to the tires 8 of the driving wheels through a ring gear shaft 4a of the planetary gear mechanism 4 when the generator 3 is driven by the generating torque that is output by the engine 1. Brake retaining torque for a brake 7 is estimated by detecting the position of a brake pedal stepped by a driver in a hybrid vehicle and the power generating torque of the engine 1 is controlled so that the engine torque reaction force that is transmitted to the tires 8 of the driving wheels is smaller than the estimated brake retaining torque. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle and an engine control method.

  In a conventional hybrid vehicle, as described in Patent Document 1, as a technique for preventing energy loss when the vehicle is stopped, an engine torque reaction force during power generation while the vehicle is stopped is arranged on a driving force shaft. A mechanism has been proposed in which the motor torque for canceling the engine torque reaction force is unnecessary and the electric loss of the inverter is eliminated by receiving the braking force of the disc brake.

JP 2004-343934 A

However, the conventional technique such as Patent Document 1 has the following problems.
That is, the brake braking force prevents the engine torque reaction force during power generation while the vehicle is stopped from being transmitted to the drive wheels, but the brake braking force is increased or decreased by the depression force of the driver depressing the brake pedal. Therefore, when the pedal force of the brake pedal is not sufficient, the engine torque reaction force overcomes the brake braking force, and the vehicle moves forward against the driver's intention while the vehicle is stopped. Things happen.
The present invention has been made in view of such a problem, and an object of the present invention is to provide a hybrid vehicle that can surely cancel the engine torque reaction force transmitted to the drive wheels during power generation while the vehicle is stopped.

  The hybrid vehicle and the engine control method according to the present invention estimate the brake holding torque based on the depression position of the brake pedal, and generate the power of the engine so that the engine torque reaction force becomes smaller than the estimated brake holding torque. It is characterized by controlling torque.

  According to the hybrid vehicle of the present invention, the brake holding torque is estimated based on the depression position of the brake pedal, and the power generation torque of the engine is controlled so that the engine torque reaction force is smaller than the estimated brake holding torque. Since the engine torque reaction force can always be canceled by the brake holding torque, it is possible to prevent the vehicle from moving forward while the vehicle is stopped against the driver's intention. be able to.

It is a conceptual diagram which shows the structural example of the hybrid vehicle which concerns on this invention. 4 is a flowchart for explaining an example of a control operation of the hybrid vehicle according to the present invention. It is a map which shows an example of the relationship between a driver | operator's brake pedal force and a braking force increase possible ratio. It is a map which shows an example of the relationship between the engine torque and engine speed in the hybrid vehicle which concerns on this invention. FIG. 6 is a collinear diagram showing an example of the rotation operation of the planetary gear mechanism 4 by the hybrid vehicle engine control method according to the present invention.

Hereinafter, embodiments of a hybrid vehicle according to the present invention will be described with reference to the drawings.
(Configuration example of embodiment)
First, a configuration example of a hybrid vehicle according to the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram showing a configuration example of a hybrid vehicle according to the present invention, and shows a system configuration example of a control mechanism of a hybrid vehicle. As shown in FIG. 1, the hybrid vehicle according to the present embodiment connects an engine 1, a motor 2, and a generator 3 via a planetary gear mechanism 4 including a carrier, a ring gear, and a sun gear, and drives the motor 2. A stepped transmission 5 for shifting the motor gear ratio is disposed on the shaft. The drive shaft of the tire (drive wheel) 8 is provided with a brake 7 made of, for example, a hydraulically controlled disc brake, and is connected to the ring gear shaft 4 a of the planetary gear mechanism 4 via the final gear 6. It is configured.

  Here, the rotating shaft of the engine 1 is connected to a carrier composed of a plurality of (four in the case of FIG. 1) planetary gears (gears meshing with both the ring gear and the sun gear) in the configuration of the planetary gear mechanism 4. ing. The drive shaft of the motor 2 is connected to the ring gear of the internal gear in the configuration of the planetary gear mechanism 4 via the stepped transmission 5. And the rotating shaft of the generator 3 is connected to the sun gear of the external gear arranged on the same circle as the ring gear in the configuration of the planetary gear mechanism 4. With such a configuration, the engine torque reaction force 1 b in the ring gear shaft 4 a of the engine 1 is transmitted to the drive shaft of the tire 8 through the final gear 6.

Moreover, it is comprised so that charging energy may be supplied to the battery 9 from the generator 3 via the inverter which is not illustrated according to the SOC (State of Charge: remaining capacity) state of the battery 9. The motor 2 is configured to be driven by being supplied with electric power from the battery 9 via the inverter 10.
That is, when the traveling state of the hybrid vehicle is in a predetermined motor drive region, the driving force of the motor 2 is applied to the drive shafts of the ring gear shaft 4a, the final gear 6 and the tire 8 via the stepped transmission 5. It is configured to be transmitted.

  Generally, when the driver performs an operation of decelerating in a state where the speed change mechanism of the motor 2, that is, the stepped transmission 5 is fastened to the high gear, the hybrid vehicle has a predetermined low speed range (for example, When the vehicle reaches a speed range of approximately 7 [Km / h] or less), the stepped transmission 5 is set to a low gear before the vehicle stops in order to ensure the maximum driving force when the vehicle restarts from a stopped state. Re-conclude with

  At this time, the motor 2 reduces the regenerative torque generated to regenerate deceleration energy to 0 [Nm], shifts the gear of the stepped transmission 5, and re-engages with the low gear. In order to avoid a change in the driving force, the regenerative torque is controlled not to be restored. Therefore, the deceleration energy during this time is released as thermal energy of the brake 7.

In the engine control method for a hybrid vehicle according to the present invention, the engine 1 generates a power generation torque 1a for generating power by the generator 3 according to the SOC (remaining capacity) state of the battery 9, and stops the planetary gear. Even when the engine torque reaction force 1b is generated on the ring gear shaft 4a of the mechanism 4, the engine torque Tm = 0 [Nm], which is a speed change condition during stopping, can be satisfied. The output torque is controlled.
Here, when the vehicle is stopped, the SOC (remaining capacity) of the battery 9 is reduced, power is generated by the engine 1, and charging energy is supplied from the generator 3 to the battery 9. Depending on the characteristics of the planetary gear mechanism 4, part of the engine torque is transmitted to the ring gear shaft 4a as the engine torque reaction force 1b.

  In order to prevent the engine torque reaction force 1b from being transmitted to the ring gear shaft 4a from being transmitted to the drive shaft of the tire 8, the motor 2 connected to the ring gear shaft 4a via the speed reduction mechanism of the stepped transmission 5 is used. A torque that cancels the engine torque reaction force 1b is generated to prevent the engine torque reaction force 1b from being transmitted to the drive shaft of the tire 8, or the driver's brake pedal among the engine torque reaction force 1b The engine torque reaction force 1b is prevented from being transmitted to the drive shaft of the tire 8 by sharing the torque exceeding the range in which the brake braking force of the brake 7 generated by the pedaling force can be canceled out. Measures to do this are also possible.

  However, with such a measure, it becomes impossible to satisfy the motor torque Tm = 0 [Nm], which is the speed change condition during stopping, and the stepped transmission 5 cannot be shifted to the low gear state, and the vehicle is stopped. When starting a vehicle, there is a case where the motor gear ratio is not suitable for starting, and the problem that the starting driving force may be less than the driver's intention may be solved. Can not.

  On the other hand, in this embodiment, when the vehicle is stopped, the brake holding torque is estimated based on the depression position of the brake pedal, and the engine torque reaction force 1b is smaller than the estimated brake holding torque. That is, as shown in FIG. 1, the engine output torque (power generation torque) is controlled so that only the brake holding torque of the brake 7 can be used to completely cancel the engine torque reaction force 1b. Thus, as described above, control is performed so as to always maintain the speed change condition during the stop of the motor torque Tm = 0 [Nm].

  Therefore, by always setting the motor torque Tm = 0 [Nm] when the vehicle is stopped, the stepped transmission 5 can be shifted to a motor gear ratio suitable for restarting the stopped hybrid vehicle. In addition to being able to completely prevent the stopped hybrid vehicle from moving against the driver's intention, it is also possible to avoid the problem that the starting driving force falls below the driver's intention Can do.

Here, the control operation of the hybrid vehicle of the present embodiment will be described using the flowchart shown in FIG.
FIG. 2 is a flowchart for explaining an example of the control operation of the hybrid vehicle according to the present invention, and shows an example of the engine control method according to the present invention.
In the flowchart of FIG. 2, first, the following three conditions are determined: whether or not the vehicle is in a stopped state, whether or not there is a charging request accompanying a decrease in the remaining capacity of the battery 9, and whether or not the brake pedal switch is turned on / off. It is determined whether or not the condition is satisfied (step S1).
(1) The vehicle speed VSP≈0 [Km / h] (the vehicle is in a stopped state) (2) The charging request due to a decrease in the remaining capacity of the battery 9 is YES (there is a charging request) (3) Brake The pedal SW is ON (the brake 7 is depressed). When the above three conditions are satisfied, the routine proceeds to a control routine for setting the motor torque Tm to 0 [Nm]. On the other hand, if not satisfied, the current state is continued.

  When the control routine for setting the motor torque Tm to 0 [Nm] is entered, first, the motor torque Tm is set to 0 [Nm], and a gear switching request for switching the gear of the stepped transmission 5 is made by the driver's operation. It is confirmed whether or not an input has been made (step S2). If no gear change request has been input (no in step S2), the process returns to the normal routine.

On the other hand, when the motor torque Tm is set to 0 [Nm] and a gear switching request for switching the gear of the stepped transmission 5 is input (yes in step S2), the process proceeds to the next step S3. The gear switching request is automatically input when the driver shifts the stepped transmission 5 of the motor 2 from the low gear state to another gear state.
Next, it is possible to measure the depression force of the brake pedal by the driver, that is, the depression position of the brake pedal, to estimate the braking force of the brake 7 composed of, for example, a hydraulically controlled disc brake, and to completely cancel the engine torque reaction force 1b. The brake holding torque Tbr indicating the braking force that can be set is set (step S3).

  Here, the brake braking force that is set as the brake holding torque Tbr in consideration of the brake hydraulic pressure that can be increased by a brake hydraulic pressure booster pump or the like mounted on the hybrid vehicle, and the reaction force to the brake pedal that accompanies the brake hydraulic pressure. Is set using the relationship between the brake depression force (brake pedal depression position) and the braking force increase possible ratio as shown in the map (MAP) of FIG. In other words, the brake holding torque Tbr is a brake braking force obtained by further increasing a predetermined increase rate (for example, about 10 &) that is predetermined as the amount of cancellation of the engine torque reaction force 1b with respect to the required braking force of the driver who has depressed the brake pedal. That is, the brake braking force is set as the sum of the driver's required braking force and the braking torque for canceling the engine torque reaction force 1b.

  FIG. 3 shows a map (MAP) showing an example of the relationship between the driver's brake pedal force (depressed position of the brake pedal) and the braking force increase possible ratio, and the brake holding torque Tbr for determining the brake holding torque Tbr. An example of the determination map is shown. As shown in FIG. 3, in the case of a hydraulically controlled disc brake, the brake pedal force substantially corresponds to the hydraulic pressure (Pr_br) of the brake 7, and is approximately proportional to the brake pedal force, that is, the hydraulic pressure (Pr_br). The upper limit value of the braking force increase possible ratio capable of increasing the braking force is determined.

  The correspondence relationship between the brake pedal force and the braking force increase possible ratio as shown in FIG. 3 is registered in advance as a brake holding torque Tbr determination map, so that the brake holding torque determination map as shown in FIG. 3 is referred to. Then, within a range of the braking force increase possible ratio corresponding to the brake pedal depression position, a predetermined constant increase ratio is estimated from the brake pedal depression position of the driver as a braking torque for canceling the engine torque reaction force 1b. The brake holding torque Tbr can be determined by further increasing the pressure against the required braking force.

  Here, in the present embodiment, it is assumed that the upper limit of the braking force increase possible ratio corresponding to the brake pedal depression position is about 10% of the required braking force estimated from the brake pedal depression position, and the engine torque reaction As described above, the constant increase rate determined in advance as the force 1b canceling amount is set to 10% corresponding to the upper limit value with respect to the required braking force estimated from the brake pedal depression position.

  Next, an upper limit engine torque that can prevent the engine torque reaction force 1b generated by the engine 1 from being transmitted to the drive shaft of the tire 8 by the braking force generated by the brake holding torque Tbr is set as an allowable engine torque Te_capa. Calculate and set (step S4). That is, based on the brake holding torque Tbr set in step S3, an allowable engine torque Te_capa that is an upper limit value that is allowed to be output from the engine 1 is calculated as follows.

That is, in order to control the engine torque reaction force 1b from the engine 1 to be equal to or less than the brake holding torque Tbr set in step S3, the engine torque that is allowed to be generated by the engine 1 by the brake holding torque Tbr. The upper limit of is limited.
Therefore, the engine 1 may be generated by converting the upper limit value at which the engine torque reaction force 1b does not exceed the braking torque of the brake 7, that is, the brake holding torque Tbr, into the engine torque based on the following equation (1). The maximum allowable engine torque Te_capa can be determined.
Te_capa = Tbr / final gear ratio / (1 + ρ) / ρ (1)
Where ρ = number of teeth of ring gear / number of teeth of sun gear

Next, as shown in the required engine torque setting map (MAP) in FIG. 4, the charging request output line Pch determined by the required charging energy of the battery 9 and the high-efficiency output line Po that provides output energy for performing high-efficiency operation. Based on the above, the required output energy Pe of the engine 1 is obtained and set (step S5). That is, the intersection Pe of the charge request output line Pch and the high efficiency output line Po is obtained and set as the required output energy Pe.
Further, as shown in the required engine torque setting map of FIG. 4, the required engine torque Te and the required engine speed Ne of the engine 1 for outputting the required output energy Pe are obtained and set (step S6).

  FIG. 4 is a map showing an example of the relationship between the engine torque and the engine speed in the hybrid vehicle according to the present invention, and the required engine torque Te and the required engine speed Ne corresponding to the required output energy Pe of the engine 1. Shows an example of a required engine torque setting map showing the corresponding relationship. An engine for satisfying the required output energy Pe of the engine 1 corresponding to the required charging energy of the battery 9 in step S5 and step S6 by registering a required engine torque setting map as shown in FIG. 4 in advance. It is possible to easily calculate the required engine torque Te and the required engine speed Ne.

Here, the required engine torque Te determined by the required charging energy of the battery 9 is set to be equal to or less than the allowable engine torque Te_capa calculated in step S4.
That is, the required engine torque Te obtained in step S6 is compared with the allowable engine torque Te_capa (step S7). If the required engine torque Te is equal to or smaller than the allowable engine torque Te_capa (yes in step S7), the request A command to the engine 1 to allow the engine torque Te and the required engine speed Ne to be set to the target engine torque Tm (power generation torque 1a) and the target engine speed Nm to be set in the engine 1 is permitted.

On the other hand, as illustrated in FIG. 4, when the requested engine torque Te exceeds the allowable engine torque Te_capa (no in step S7), the process proceeds to the next step S8.
When the requested engine torque Te exceeds the allowable engine torque Te_capa, first, the allowable engine torque Te_capa is set as a corrected engine torque Te_hosei for the engine 1. Furthermore, in order to satisfy the required charging energy of the battery 9, as shown in FIG. 4, the position of the corrected output energy Pe_hosei that is the intersection of the required output energy Pe and the allowable engine torque Te_capa on the charging required isoelectric output line Pch. , And based on the set corrected engine torque Te_hosei, the rotational speed obtained by increasing the rotational speed of the engine 1 is determined as the corrected engine rotational speed Ne_hosei (step S8).

That is, the corrected engine torque Te_hosei and the corrected engine speed Ne_hosei are determined by the following equations (2) and (3), respectively.
Correction engine torque Te_hosei = allowable engine torque Te_capa
... (2)
Correction engine speed Ne_hosei
= Required charging energy / corrected engine torque Te_hosei
/ 2π * 6000 * 10
... (3)
Thereafter, the corrected engine torque Te_hosei (that is, the allowable engine torque Te_capa) and the calculated corrected engine speed Ne_hosei are set to the target engine torque Tm (corrected power generation torque 1a) and the target engine speed Nm to be set in the engine 1. The command to the engine 1 to perform is permitted.

  When the required engine torque Te exceeds the allowable engine torque Te_capa, that is, the engine torque reaction force 1b due to the power generation torque 1a of the engine 1 corresponding to the required charging energy of the battery 9 exceeds the brake holding torque Tbr in the brake 7. If it is, the power generation torque 1a is limited to the correction engine torque Te_hosei, that is, the power generation torque 1a reduced to the allowable engine torque Te_capa, but the engine 1 is increased by the correction engine rotation speed Ne_hosei increased from the required engine rotation speed Ne. Will rotate, and the rotational speed of the generator 3 driven via the planetary gear mechanism 4 will also increase, so that the amount of power generation can be increased and the battery 9 can be requested as required. Can supply charging energy That. Therefore, even if the power generation request of the generator 3 increases, it is ensured that the engine torque reaction force 1b due to the power generation torque 1a of the engine 1 exceeds the brake holding torque Tbr while supplying the power generation amount according to the request. Therefore, the stopped vehicle does not start against the driver's intention and can be stopped.

  After completing the above steps, when the command of the target torque and the number of revolutions to the engine 1 is completed, the switching operation of the inverter 10 that controls the motor 2 is stopped, and the motor torque Tm is set to 0 [Nm]. After setting (step S10), the gear of the stepped transmission 5 connected to the drive shaft of the motor 2 is set to a motor gear ratio suitable when the stopped vehicle restarts (step S11).

  By performing the control as described above, the motor torque Tm of the motor 2 is set to 0 [Nm] while the engine torque reaction force 1b of the engine 1 is transmitted to the ring gear shaft 4a while the vehicle is stopped. Even if the torque for canceling the engine torque reaction force 1b from the motor 2 is made zero, the vehicle can be stopped as intended by the driver by controlling the brake braking force of the brake 7 and the engine torque. .

Further, when the vehicle is stopped, the motor torque of the motor 2 is always set to 0 [Nm] regardless of whether or not the battery 9 is charged, so that the stepped transmission 5 is connected to the drive shaft of the motor 2. Even in such a hybrid vehicle, the gear of the stepped transmission 5 can be shifted, and it is possible to avoid a state where the motor gear ratio is not suitable for starting when the vehicle starts.
Furthermore, by such a control, the deceleration energy is recovered until the vehicle stops (for example, about 7 [Km / h] or less) while the stepped transmission 5 is kept engaged with the high gear during deceleration. Thus, an energy recovery rate increase of about 5% can be obtained as compared with the prior art.

  As described above, the required engine torque Te and the required engine speed Ne of the engine 1 are determined according to the required charging power when the SOC (remaining capacity) of the battery 9 is reduced. In the present embodiment, Instead of outputting it as a command to the engine 1 as it is, first, the required engine torque Te is set to the allowable engine torque Te_capa calculated based on the brake holding torque Tbr (that is, to the tire (drive wheel) 8 by the brake holding torque Tbr). The engine torque is compared with the upper limit engine torque that can suppress the transmission of the engine torque reaction force 1b.

As a comparison result, when the required engine torque Te is equal to or less than the allowable engine torque Te_capa, the required engine torque Te and the required engine speed Ne are set to the engine 1 as the target engine torque Tm (power generation torque 1a) and the target engine speed Nm. After commanding, control is performed to set the motor torque Tm to 0 [Nm].
On the other hand, when the required engine torque Te exceeds the allowable engine torque Te_capa, correction is performed based on the allowable engine torque Te_capa, the corrected engine torque Te_hosei and the corrected engine speed Ne_hosei are calculated, and the calculated corrected engine torque Te_hosei is calculated. And the corrected engine speed Ne_hosei are commanded to the engine 1 as the target engine torque Tm (corrected power generation torque 1a) and the target engine speed Nm, and then the motor torque Tm is set to 0 [Nm].

  FIG. 5 is a collinear diagram showing an example of the rotation operation of the planetary gear mechanism 4 according to the engine control method of the hybrid vehicle according to the present invention. The carrier constituting the planetary gear mechanism 4 (to which the rotation shaft of the engine 1 is connected). A plurality of planetary gears), a ring gear (a gear to which the drive shaft of the motor 2 is connected), a sun gear (a gear to which the rotating shaft of the generator 3 is connected), and the mechanical relationship between the rotational speed and torque. . In the alignment chart of FIG. 5, it is estimated from the engine torque reaction force 1 b at the required engine torque Te for the engine 1 for supplying the required charging energy of the battery 9 and the depression force of the brake 7 (depressing position of the brake pedal). As a result of comparison with the brake holding torque Tbr, the state before correction of the power generation torque 1a of the engine 1 in the case of the relationship {engine torque reaction force 1b> brake holding torque Tbr} is shown by a broken line, and the state after correction is shown. Shown in bold lines. That is, the case where the relationship before the correction is {engine torque reaction force 1b> brake holding torque Tbr} is indicated by a broken line, and the case where the relationship {engine torque reaction force 1b ≦ brake holding torque Tbr} is indicated by a thick line. Is shown.

  As shown in the nomogram of FIG. 5, when the required engine torque Te exceeds the allowable engine torque Te_capa (that is, {engine torque reaction force 1b> brake holding torque Tbr}), as described above, The required engine torque Te is switched to the corrected engine torque Te_hosei equal to the allowable engine torque Te_capa to obtain the target engine torque Tm (power generation torque 1a), and the required engine speed Ne is accordingly set based on the required charging energy. By switching to the corrected engine speed Ne_hosei increased by the number, the engine 1 is instructed as the target engine speed Nm.

Therefore, the carrier connected to the rotation shaft of the engine 1 moves from the position of the required rotation speed Ne on the broken line to the position of the corrected rotation speed Ne_hosei on the thick line as shown by the arrow as shown in FIG. It will change and it will rotate at the increased rotation speed.
Even when the required engine torque Te exceeds the allowable engine torque Te_capa (that is, {engine torque reaction force 1b> brake holding torque Tbr}), as indicated by the thick line, {engine torque reaction force Since the output energy of the engine 1 is controlled so as to maintain the relationship of 1b ≦ brake holding torque Tbr}, the engine torque reaction force 1b can be surely canceled by the brake holding torque Tbr. Thus, it is not necessary to output a canceling torque for canceling the engine torque reaction force 1b from the motor 2, and the rotation speed of the motor 2 can be controlled to zero, so that the motor 2 is driven as shown in FIG. The rotation speed of the ring gear connected to the shaft via the stepped transmission 5 is also zero.

  As for the generator 3, when the required engine torque Te exceeds the allowable engine torque Te_capa (that is, {engine torque reaction force 1b> brake holding torque Tbr}), the output of the engine 1 is accordingly changed. Since the energy is controlled and corrected so as to limit the power generation torque 1a for the generator 3, the rotational speed of the generator 3 is set to the corrected engine rotational speed Ne_hosei of the engine 1 in order to output the required power generation energy. Accordingly, the correction is made so as to increase the required generator speed.

Therefore, the rotational speed of the sun gear connected to the rotating shaft of the generator 3 is also the same as the corrected rotational speed on the thick line as shown by the arrow from the position of the required rotational speed on the broken line as shown in FIG. The position is changed and the rotation speed is increased.
By performing such control, in the prior art, when the engine torque reaction force 1b from the engine 1 exceeds the braking torque of the brake, the motor is also provided with a cancellation torque for canceling the engine torque reaction force 1b. In the present embodiment, the engine torque reaction force 1b exceeding the brake holding torque Tbr can be controlled so that the motor torque Tm of the motor 2 is always set when the vehicle is stopped. Even when set to 0 [Nm], it is possible to completely prevent the stopped vehicle from moving forward against the driver's intention.

Further, after commanding the engine 1 with the required engine torque Te and the required engine speed Ne as the target engine torque Tm and the target engine speed Nm, or the engine 1 with the corrected engine torque Te_hosei and the corrected engine speed Ne_hosei. After the command, the switching operation of the inverter 10 that controls the motor 2 is stopped and the motor torque is set to 0 [Nm]. Therefore, even in the hybrid vehicle having the stepped transmission 5 immediately below the motor 2, the vehicle is stopped. The stepped gear can be shifted regardless of whether or not the battery 9 is being charged.
Here, in the present embodiment, the brake holding torque estimating means is configured by the process of estimating the brake holding torque in step S3, and the power generation torque control means is configured by the processes of steps S4 to S9.

1 Engine 1a Power generation torque 1b Engine torque reaction force 2 Motor 3 Generator 4 Planetary gear mechanism 4a Ring gear shaft 5 Stepped transmission 6 Final gear 7 Brake 8 Tire (drive wheel)
9 Battery 10 Inverter

Claims (7)

The driving force of the engine is transmitted to the generator and the driving wheel via the planetary gear mechanism, and the driving force of the motor is transmitted to the driving wheel via the planetary gear mechanism. When the generator is driven by the power generation torque that is the driving force output from the engine, the engine torque reaction force that is the reaction force of the power generation torque is transmitted to the driving wheel side via the planetary gear mechanism. In hybrid vehicles,
Brake holding torque estimating means for estimating the brake holding torque based on the depression position of the brake pedal;
Power generation torque control means for controlling the power generation torque so that the engine torque reaction force transmitted to the drive wheel is smaller than the estimated brake holding torque;
A hybrid vehicle characterized by comprising:   2. The hybrid vehicle according to claim 1, wherein when the engine torque reaction force transmitted to the drive wheels exceeds the estimated brake holding torque, the power generation torque control means rotates the generator. The engine power generation torque is controlled so that the engine torque reaction force transmitted to the drive wheels becomes smaller than the estimated brake holding torque by shifting in a direction to increase the engine speed. Hybrid vehicle.   3. The hybrid vehicle according to claim 1, wherein the power generation torque control means is a driving force required for the engine to generate a required charging energy required for charging a battery by the generator while the vehicle is stopped. 4. When the engine torque reaction force generated by the required engine torque exceeds the brake holding torque, the required engine torque, which has been reduced to an allowable engine torque at which the engine torque reaction force becomes equal to the brake holding torque, A hybrid vehicle characterized in that the engine speed is increased to a speed at which the required charging energy can be output from the generator.   The hybrid vehicle according to any one of claims 1 to 3, wherein the brake holding torque estimating means is based on a depression position of the brake pedal when estimating the brake holding torque based on a depression position of the brake pedal. The brake braking force estimated to be demanded by the driver is further increased by a predetermined increase ratio within the range of possible increase ratios where the brake braking force can be increased at the depressed position. A hybrid vehicle characterized in that torque is set as the brake holding torque.   5. The hybrid vehicle according to claim 1, wherein after the power generation torque of the engine is controlled so that the engine torque reaction force is smaller than the brake holding torque, the motor torque of the motor is reduced to zero. A hybrid vehicle characterized by that.   6. The hybrid vehicle according to claim 5, wherein after the motor torque of the motor is made zero, the motor gear ratio of the stepped transmission connected to the drive shaft of the motor is changed. The driving force of the engine is transmitted to the generator via the planetary gear mechanism, and the driving force of the motor is transmitted to the driving wheel via the planetary gear mechanism. The engine torque reaction force, which is the reaction force of the power generation torque, is transmitted to the drive wheel side via the planetary gear mechanism when the generator is driven by the power generation torque that is the driving force output by An engine control method for a hybrid vehicle,
Brake holding torque is estimated based on the depression position of the brake pedal, and the power generation torque is controlled so that the engine torque reaction force transmitted to the drive wheel is smaller than the estimated brake holding torque. An engine control method characterized by the above.

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