JP2010125877A - Controller for hybrid electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a parallel type hybrid electric vehicle charging a battery while enhancing an engine efficiency. <P>SOLUTION: A required engine efficiency ηr of an engine corresponding to at least required driving torque Treq is computed from an engine efficiency map in which a degree of engine efficiency η is set in advance according to engine driving torque and an engine rotation speed Ne, based on the required driving torque Treq and the engine rotation speed Ne, and whether electric power can be generated by the engine is determined based on a level of the required engine efficiency ηr (S18, S22). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a hybrid electric vehicle, and more particularly to a control technology for a parallel hybrid electric vehicle.

2. Description of the Related Art Conventionally, so-called parallel hybrid electric vehicles have been developed and put into practical use in which an engine and an electric motor are mounted on a vehicle and the driving force of the engine and the driving force of the electric motor can be transmitted to the driving wheels of the vehicle.
In such a parallel hybrid electric vehicle, a battery is mounted to drive the electric motor. However, when the electric power stored in the battery decreases, the electric motor is used as a generator to charge the battery. I have to.

  For example, when the vehicle decelerates, the electric power from the wheels is transmitted to the electric motor, so that the electric motor is used as a generator and thus as a braking device, and the braking energy is regenerated into electric energy to charge the battery. In addition, when the vehicle is traveling normally, the electric motor is operated as a generator using the driving force of the engine as necessary to charge the battery.

By the way, when the electric motor is used as a generator by utilizing the driving force of the engine in this way, it is necessary to increase the driving force of the engine. It is desirable to reduce the amount of
Therefore, for example, the ratio of the battery discharge power amount and the fuel reduction amount when the electric motor driving or the electric motor assist driving is performed with respect to the engine driving is obtained as a driving index, and when the power is generated with the increased engine output A system in which the ratio between the battery charge power amount and the fuel increase amount is obtained as a charge index, and if the drive index is smaller than the reference value, the motor travels or assists the motor, and if the charge index is greater than the reference value, the charge travels Is known (Patent Document 1).

In addition, for example, the running state of the vehicle is estimated based on the distribution of the required power to the electric motor in the past 100 seconds, the required power varies greatly according to the running state, and a large current is discharged from the battery or the battery is charged with a large current. If the load fluctuation of the battery is large, the battery life is extended by absorbing the load fluctuation with the generated power of the engine. In this case, the engine is driven in the best emission range and the best fuel consumption range. An apparatus having a configuration is known (Patent Document 2).
Japanese Patent Laying-Open No. 2005-94865 JP-A-9-98515

  However, in the technologies disclosed in Patent Documents 1 and 2, engine control is performed mainly for the purpose of reducing fuel consumption. For example, in Patent Document 1, the charging index is larger than the reference value. Even if it is determined that charging can be performed, it is possible that the engine efficiency is poor (low-load operation) without knowing it, and it is not preferable.

Moreover, in patent document 2, since the running state of a vehicle is estimated based on distribution of the required electric power to the electric motor in the past 100 seconds, and engine control is performed, it is in the moment at the moment which wants to perform engine control. There is also a problem that the optimum operating conditions cannot be selected.
The present invention has been made in view of such problems, and an object of the present invention is to control a hybrid electric vehicle capable of charging a battery while improving engine efficiency in a parallel hybrid electric vehicle. To provide an apparatus.

  In order to achieve the above object, a control apparatus for a hybrid electric vehicle according to claim 1 of the present invention is capable of transmitting a driving force to the driving wheel by an engine capable of transmitting the driving force to the driving wheel of the vehicle and a stored power of a battery. And a required drive torque obtained as a drive torque to be output by at least one of the engine and the electric motor according to an operating state of the vehicle. Based on the above, in a control apparatus for a hybrid electric vehicle having control means for controlling the engine and the electric motor, required torque detection means for detecting the required drive torque, rotation speed detection means for detecting engine rotation speed, and Based on the information from the required torque detection means and the information from the rotation speed detection means, the engine drive torque and Engine efficiency calculation means for calculating a required engine efficiency of the engine corresponding to at least the required drive torque from an engine efficiency map in which the degree of engine efficiency is set in accordance with the engine speed, and the engine efficiency calculation means Engine power generation availability determination means for determining whether or not power generation by the engine can be performed based on the required engine efficiency, and the control means can perform power generation by the engine by the engine power generation availability determination means. When the determination is made, the motor is caused to generate electricity by the engine.

  According to a control apparatus for a hybrid electric vehicle according to a second aspect of the present invention, the engine according to the first aspect according to the engine drive torque and the engine speed based on the information from the required torque detecting means and the information from the rotational speed detecting means. From the engine efficiency map in which the degree of efficiency is set, the required engine efficiency of the engine corresponding to the required drive torque and the addition corresponding to the additional drive torque obtained by adding the power generation drive torque for power generation of the motor to the required drive torque Engine efficiency calculating means for calculating engine efficiency, and engine power generation feasibility determining means for comparing the required engine efficiency obtained by the engine efficiency calculating means and the additional engine efficiency to determine whether power generation by the engine can be performed. The control means is determined by the engine power generation execution availability determination means. When power generation by the serial engine is determined to be performed, characterized in that for generating operation of the electric motor by the engine on the basis of the additional drive torque.

  According to a hybrid electric vehicle control device of a third aspect, in the second aspect, the engine efficiency calculation means obtains a maximum engine efficiency as the additional engine efficiency, and the engine power generation execution feasibility determination means includes the required drive torque and the Based on the difference with the additional drive torque corresponding to the maximum engine efficiency, it is determined whether or not power generation by the engine can be performed, and when the control unit determines that power generation by the engine can be performed by the engine power generation execution determination unit The electric motor is caused to generate electricity by the engine based on the additional driving torque that provides the maximum engine efficiency.

  According to a fourth aspect of the present invention, there is provided a control apparatus for a hybrid electric vehicle according to the third aspect, wherein the power generation drive torque is a maximum power generation drive torque in the electric motor, and the difference between the required drive torque and the additional drive torque that provides the maximum engine efficiency. When the maximum power generation driving torque is small, the control means causes the engine to generate power based on an additional driving torque that is the sum of the required driving torque and the maximum power generation driving torque. To do.

  According to a fifth aspect of the present invention, there is provided a control apparatus for a hybrid electric vehicle according to the first aspect of the present invention, in accordance with the engine drive torque and the engine speed in advance based on the information from the required torque detecting means and the information from the rotational speed detecting means. Fuel consumption calculation means for calculating a required fuel consumption amount of the engine corresponding to at least the required drive torque from a fuel consumption map in which a degree of fuel consumption is set, and the engine power generation execution propriety determination means includes: Based on the magnitude of the required engine efficiency obtained by the engine efficiency computing means and the magnitude of the requested fuel consumption obtained by the fuel consumption calculating means, it is determined whether or not the engine can generate power, and the control means If it is determined by the engine power generation feasibility determination means that power generation by the engine can be performed, the energy Jin By characterized thereby generating operation of the motor.

  According to a hybrid electric vehicle control device of a sixth aspect, in the second or third aspect, the engine drive torque and the engine rotational speed are preliminarily determined based on the information from the required torque detecting means and the information from the rotational speed detecting means. A power generation driving torque for power generation of the motor is added to the required fuel consumption amount and the required driving torque of the engine corresponding to the required driving torque from the fuel consumption map in which the degree of fuel consumption is set according to Fuel consumption calculating means for calculating an additional fuel consumption amount corresponding to the additional drive torque is provided, and the engine power generation feasibility determination means includes a conversion work corresponding to an increase in engine efficiency by adding the power generation drive torque and generated power The gain mechanical work which is the sum of the work of the electric motor and the fuel by adding the power generation driving torque It is determined whether or not the engine can generate power by comparing with the lost mechanical work that is the conversion work for the increase in cost, and the control means can execute the power generation by the engine by the engine power generation execution determination part. When the determination is made, the motor is caused to generate power by the engine based on the additional driving torque.

The hybrid electric vehicle control device according to claim 7, wherein the engine power generation feasibility determination unit according to claim 6 determines a difference or ratio between the gain mechanical work and the lost mechanical work in accordance with a remaining charge rate of the battery. Compared with a threshold value, it is determined whether or not the engine can generate power.
In the control apparatus for a hybrid electric vehicle according to claim 8, in claim 2, 3, 6, or 7, when the remaining charge rate of the battery is higher than a first predetermined value, the control means sets the power generation drive torque. The electric motor is caused to generate electricity by the engine based on the reduced additional driving torque.

  In the control apparatus for a hybrid electric vehicle according to claim 9, in claim 2, 3, 6, or 7, when the remaining charge rate of the battery is lower than a second predetermined value, the control means sets the power generation drive torque. The electric motor is caused to generate electricity by the engine based on the increased additional driving torque.

  According to the hybrid electric vehicle control apparatus of the first aspect of the present invention, in the parallel hybrid electric vehicle, the degree of engine efficiency is set in advance according to the engine driving torque and the engine rotational speed by the engine efficiency calculation means. The required engine efficiency of the engine corresponding to at least the required drive torque is calculated from the engine efficiency map, and the power generation by the engine is performed based on the magnitude of the required engine efficiency calculated by the engine efficiency calculation means by the engine power generation execution determination unit. When it is determined whether or not power generation can be performed and it is determined that power generation by the engine can be performed, the electric motor performs power generation operation by the engine.

Therefore, when charging the battery while the vehicle is running, for example, when the engine efficiency is higher than the required engine efficiency, the power generation by the engine is allowed, and conversely the required engine efficiency Therefore, when the engine efficiency is lower, the engine can generate power more efficiently by not generating power.
In addition, engine control is performed by obtaining the required engine efficiency from the engine efficiency map according to the engine drive torque and engine rotation speed, so the engine control can be performed by selecting the optimum operating condition at the moment when the engine control is desired. It can be carried out.

Thereby, a highly efficient parallel hybrid electric vehicle can be realized.
According to the hybrid electric vehicle control apparatus of the second aspect, the engine efficiency calculation means generates the power generation drive for generating the electric motor from the engine efficiency map to the required engine efficiency and the required drive torque of the engine corresponding to the required drive torque. The additional engine efficiency corresponding to the additional drive torque with the torque added is calculated, and the engine power generation execution propriety determination means compares the required engine efficiency obtained by the engine efficiency calculation means with the additional engine efficiency, and performs the power generation by the engine. When it is determined whether or not power generation by the engine is possible, the electric motor is generated by the engine based on the additional driving torque.

Therefore, when charging the battery while the vehicle is running, if the additional engine efficiency with the power generation driving torque added is higher than the required engine efficiency, power generation by the engine is allowed, and conversely, the additional engine is higher than the required engine efficiency. When the efficiency is low, the engine can generate power efficiently by not generating the engine.
According to the hybrid electric vehicle control apparatus of claim 3, the engine power generation execution determination unit determines whether or not the engine can generate power based on the difference between the required drive torque and the additional drive torque corresponding to the maximum engine efficiency. If it is determined that power generation by the engine can be performed, the electric motor is generated by the engine based on the additional drive torque that provides the maximum engine efficiency.

Therefore, when charging the battery while the vehicle is running, power generation by the engine can be efficiently performed so that the maximum engine efficiency is obtained.
According to the control apparatus for a hybrid electric vehicle of claim 4, when the maximum power generation drive torque is small with respect to the difference between the required drive torque and the additional drive torque that provides the maximum engine efficiency, the required drive torque and the maximum power generation drive torque are The electric motor is generated by the engine based on the additional drive torque that is the sum of the two.

Therefore, when charging the battery while the vehicle is running, even if the maximum power generation driving torque that can be absorbed by the generator is small, it is possible to increase the engine efficiency as much as possible and efficiently generate power by the engine. it can.
According to the control apparatus for a hybrid electric vehicle of claim 5, the fuel consumption map in which the degree of fuel consumption is set in advance according to the engine driving torque and the engine speed by the fuel consumption calculation means. The required fuel consumption amount of the engine corresponding to at least the required drive torque is calculated from the above, and the magnitude of the required engine efficiency obtained by the engine efficiency calculation means and the fuel consumption amount calculation means are obtained by the engine power generation feasibility determination means Whether or not power generation by the engine can be performed is determined based on the magnitude of the fuel consumption, and when it is determined that power generation by the engine can be performed, the motor is operated to generate power.

  Therefore, when charging the battery while the vehicle is running, for example, even if the fuel consumption increases with respect to the required fuel consumption, the engine efficiency becomes higher than the required engine efficiency. If the fuel consumption greatly increases with respect to the required fuel consumption even if the engine efficiency is higher than the required engine efficiency, By not performing the above, power generation by the engine can be performed more efficiently while preventing deterioration of fuel consumption.

As a result, a more efficient parallel hybrid electric vehicle can be realized.
According to the hybrid electric vehicle control device of the sixth aspect, the fuel consumption calculation means causes the motor to generate the required fuel consumption and the required drive torque of the engine corresponding to the required drive torque from the fuel consumption map. The additional fuel consumption corresponding to the additional drive torque to which the power generation drive torque is added is calculated, and the engine using the power generation drive torque is added by the engine power generation execution feasibility determining means and the conversion work for the increase in engine efficiency and the electric motor by the generated power Comparing the gain machine work that is the sum of the work and the loss machine work that is the conversion work of the increase in fuel consumption by adding the power generation drive torque, it is determined whether or not the engine can generate power. When it is determined that the power generation by can be performed, the electric motor is generated by the engine based on the additional driving torque.

  Therefore, when charging the battery while the vehicle is running, the gain mechanical work is greater than the lost mechanical work, that is, even if the additional fuel consumption is large relative to the required fuel consumption, When the additional engine efficiency with the drive torque added becomes sufficiently high, power generation by the engine is allowed, and conversely, the loss mechanical work is larger than the gain mechanical work, that is, even if the additional engine efficiency is higher than the required engine efficiency. By not generating power by the engine when the additional fuel consumption is larger than the required fuel consumption, power generation by the engine can be performed more efficiently while preventing deterioration of fuel consumption.

According to the control device for a hybrid electric vehicle of claim 7, the engine power generation feasibility determination means compares the difference or ratio between the gain mechanical work and the lost mechanical work with a threshold value corresponding to the remaining charge rate of the battery. It is determined whether or not the engine can generate power.
Therefore, when charging the battery while the vehicle is running, the gain mechanical work is lost according to a threshold corresponding to the remaining charge rate (SOC) of the battery based on the difference or ratio between the gain mechanical work and the lost mechanical work. When the mechanical work is larger than the mechanical work, the power generation by the engine is allowed. Conversely, when the gain mechanical work is smaller than the loss mechanical work according to the above threshold, the engine does not generate the power. It is possible to perform the process more efficiently while preventing the deterioration.

According to the control apparatus for a hybrid electric vehicle of claim 8, when the remaining charge rate of the battery is higher than the first predetermined value, the electric motor generates power by the engine based on the additional drive torque obtained by reducing the power generation drive torque. Is done.
Therefore, when the remaining charge rate (SOC) of the battery is sufficiently higher than the first predetermined value, it is less necessary to charge the battery, and power generation by the engine can be suppressed.

According to the hybrid electric vehicle control device of the ninth aspect, when the remaining charge rate of the battery is lower than the second predetermined value, the electric motor generates power by the engine based on the additional driving torque obtained by increasing the power generation driving torque. Is done.
Therefore, when the remaining charge rate (SOC) of the battery is lower than the second predetermined value, it is necessary to quickly charge the battery, and power generation by the engine can be enhanced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, the first embodiment will be described.
FIG. 1 is a block diagram of a main part of a control device for a hybrid electric vehicle 1 according to an embodiment of the present invention.
The hybrid electric vehicle 1 is a parallel hybrid electric vehicle, and an output shaft of a diesel engine (hereinafter referred to as an engine) 2 is connected to an input shaft of a clutch 4. The output shaft of the clutch 4 is, for example, a permanent magnet type. An input shaft of an automatic transmission (hereinafter referred to as “transmission”) 8 is connected via a rotating shaft of an electric motor (hereinafter referred to as “motor”) 6 that can generate electric power, such as a synchronous motor. Therefore, in this embodiment, the rotational speed of the electric motor 6 and the rotational speed of the input shaft of the transmission 8 are the same. The output shaft of the transmission 8 is connected to the left and right drive wheels 16 via a propeller shaft 10, a differential device 12 and a drive shaft 14.

Therefore, when the clutch 4 is connected, both the output shaft of the engine 2 and the rotating shaft of the electric motor 6 can be mechanically connected to the drive wheels 16 via the transmission 8, and the clutch 4 is disconnected. Sometimes only the rotating shaft of the electric motor 6 can be mechanically connected to the drive wheels 16 via the transmission 8.
The electric motor 6 operates as a motor when DC power stored in the battery 18 is converted into AC power by the inverter 20 and supplied thereto, and the output torque of the motor 6 is changed to an appropriate speed by the transmission 8. 16 is configured to be transmitted to 16. Further, when the vehicle decelerates, the electric motor 6 operates as a generator, and kinetic energy generated by the rotation of the drive wheels 16 is transmitted to the electric motor 6 through the transmission 8 and converted into AC power, thereby generating regenerative braking force. To do. Then, the AC power is converted into DC power by the inverter 20, and then charged in the battery 18. The kinetic energy generated by the rotation of the drive wheels 16 is recovered as electric energy.

  On the other hand, the output torque of the engine 2 is transmitted to the transmission 8 via the rotating shaft of the electric motor 6 when the clutch 4 is connected, and is transmitted to the drive wheels 16 after being shifted to an appropriate speed. Therefore, when the electric motor 6 operates as a motor when the output torque of the engine 2 is transmitted to the drive wheels 16, the output torque of the engine 2 and the output torque of the electric motor 6 are driven via the transmission 8, respectively. It will be transmitted to the wheel 16. That is, a part of the torque to be transmitted to the drive wheels 16 for driving the vehicle is supplied from the engine 2 and the remaining part is supplied from the electric motor 6 and assisted.

  Further, when the remaining charge rate (hereinafter referred to as SOC) of the battery 18 decreases and the battery 18 needs to be charged, the motor 6 operates as a generator even when the vehicle is running, and the engine 2 Electric power is generated by operating the electric motor 6 using a part of the output torque, and the battery 18 is charged after the generated AC power is converted into DC power by the inverter 20.

  The vehicle ECU 22 performs connection / disengagement control of the clutch 4 and shift speed switching control of the transmission 8 according to the operation state of the vehicle and the engine 2 and information from the engine ECU 24, the inverter ECU 26, and the battery ECU 28. Integrated control for appropriately operating the engine 2 and the electric motor 6 is performed in accordance with various control states such as the control state of the vehicle, start of the vehicle, acceleration, and deceleration.

  When performing such control, the vehicle ECU 22 detects an accelerator opening sensor (required torque detection means) 32 that detects the amount of depression of the accelerator pedal 30, a vehicle speed sensor 34 that detects the traveling speed of the vehicle, and the electric motor 6. Based on the detection result of the rotation speed sensor (rotation speed detection means) 36 that detects the rotation speed of the engine 2 as the input rotation speed of the transmission 8, a required torque required for traveling of the vehicle is calculated. 2 and the torque generated by the electric motor 6 are set.

The engine ECU 24 performs various controls necessary for the operation of the engine 2 itself, and at the same time, causes the engine 2 to generate the torque required for the engine 2 set by the vehicle ECU 22. Control etc.
On the other hand, the inverter ECU 26 controls the operation of the motor 6 by operating the motor 6 or the generator by controlling the inverter 20 based on the torque that should be generated by the motor 6 set by the vehicle ECU 22.

The battery ECU 28 detects the temperature of the battery 18, the voltage of the battery 18, the current flowing between the inverter 20 and the battery 18, etc., and obtains the SOC of the battery 18 from these detection results. It is sent to the vehicle ECU 22 together with the detection result.
Hereinafter, the operation and effect of the control device of the hybrid electric vehicle 1 configured as described above will be described.

  As described above, in the control apparatus for the hybrid electric vehicle 1 according to the present invention, even when the vehicle is running, power is generated by operating the motor 6 with a part of the output torque of the engine 2, and the generated power is supplied to the battery. In this case, charging of the battery 18 is performed while improving the engine efficiency. Here, first, according to the first embodiment of the control device of the hybrid electric vehicle 1. The operation and effect will be described.

Referring to FIG. 2, a travel control routine in the control device for the hybrid electric vehicle 1 according to the first embodiment executed by the vehicle ECU 22 is shown in a flowchart, and with reference to FIG. 3, the control according to the first embodiment. Is shown on the engine efficiency map, and will be described with reference to FIGS.
In step S10, it is determined whether or not the required torque (required drive torque) Treq is less than zero. Specifically, the required torque Treq is obtained based on the detection information from the accelerator opening sensor 32, and it is determined whether or not the required torque Treq is negative. If the determination result is true (Yes) and it is determined that the required torque Treq is negative, the process proceeds to step S12, and the regenerative braking force is generated by the electric motor 6 as described above to charge the battery 18 (regeneration). On the other hand, if the determination result is false (No), the process proceeds to step S14.

  In step S14, it is determined whether or not the required torque Treq is larger than the engine maximum torque Temax. When the determination result is true (Yes) and the required torque Treq is larger than the engine maximum torque Temax, it is considered that the driving force of the engine 2 is not sufficient, and the process proceeds to step S16, where the torque is as described above. A part of the engine is supplied from the engine 2 and the remaining part is supplied from the electric motor 6 (assist travel). On the other hand, if the determination result is false (No), the process proceeds to step S18.

In step S18, whether or not the additional engine efficiency η ′ corresponding to the additional driving torque T ′ added with the power generation driving torque when the motor 6 is operated as a generator is smaller than the required engine efficiency ηr in the required torque Treq. (Engine power generation execution availability determination means).
That is, as shown in FIG. 3, in the vehicle ECU 22, the relationship between the engine rotational speed Ne, the engine torque T, and the engine efficiency η is set and stored in advance as an engine efficiency map through experiments or the like (engine efficiency calculating means). In the same figure, for example, the required engine efficiency ηr with respect to the required torque Treq at the current engine speed Ne0 and the additional engine efficiency η corresponding to the additional drive torque T ′ added with the power generation drive torque to operate the electric motor 6 as a generator. 'Is shown, and the required engine efficiency ηr and the additional engine efficiency η' are compared to determine whether the required engine efficiency ηr is larger than the additional drive torque η '.

  If the determination result of step S18 is true (Yes) and it is determined that the additional engine efficiency η ′ is smaller than the required engine efficiency ηr, the electric power generation by the motor 6 is not performed, and the process proceeds to step S20 to request the required torque Treq. Thus, traveling by the driving force of the engine 2 or assist traveling by the driving force of the engine 2 and the electric motor 6 is performed. On the other hand, if the determination result of step S18 is false (No), the process proceeds to step S22.

  In step S22, power generation by the electric motor 6 is performed. That is, when it is determined that the additional engine efficiency η ′ is equal to or higher than the required engine efficiency ηr, it is possible to increase the engine efficiency η by generating electric power with the electric motor 6, and an additional driving torque that becomes the additional engine efficiency η ′. The engine 2 is operated at T ′, the electric motor 6 is operated to generate electric power, and the battery 18 is charged.

  Thus, in the control apparatus for the hybrid electric vehicle 1 according to the first embodiment of the present invention, the required engine efficiency ηr is compared with the additional engine efficiency η ′ when the electric motor 6 is operated as a generator, and the additional engine efficiency is compared. When η ′ is equal to or higher than the required engine efficiency ηr, the electric motor 6 is operated by the engine 2 to generate power. Conversely, when the additional engine efficiency η ′ is smaller than the required engine efficiency ηr, the electric motor 6 is operated by the engine 2 so that power generation is not performed.

Therefore, even when the vehicle is traveling, power generation by the engine 2 can be performed efficiently.
Also, here, the engine control is performed by obtaining the required engine efficiency ηr from the engine efficiency map in accordance with the engine rotational speed Ne, the engine torque T, and the engine efficiency η, so the optimum at the present moment when the engine control is desired. The engine 2 can be controlled by selecting various operating conditions.

Thereby, a highly efficient parallel hybrid electric vehicle can be realized.
Next, a second embodiment will be described.
In the second embodiment, the configuration of the main part of the control device of the hybrid electric vehicle 1 is as shown in FIG. 1 as in the first embodiment, and the description thereof is omitted here.
Referring to FIG. 4, a travel control routine of the control device for the hybrid electric vehicle 1 according to the second embodiment executed by the vehicle ECU 22 is shown in a flowchart, and with reference to FIGS. 5 and 6, the second embodiment. A conceptual diagram of the control is shown on the engine efficiency map, and will be described below with reference to FIGS.

In FIG. 4, steps S10 to S16 are the same as those in FIG. 2 in the first embodiment, and a description thereof will be omitted.
In step S118, it is determined whether or not the additional drive torque Tηmax that provides the maximum engine efficiency ηmax is smaller than the required torque Treq (engine power generation execution availability determination unit).
That is, as shown in FIG. 5, as in FIG. 3, the relationship between the engine rotational speed Ne and the engine torque T and the engine efficiency η is set as an engine efficiency map. The required engine efficiency ηr and the maximum engine efficiency ηmax with respect to the required torque Treq at Ne0 are respectively shown. Here, the required torque Treq and the additional drive torque Tηmax at the maximum engine efficiency ηmax are compared, and the maximum engine efficiency ηmax It is determined whether or not the additional drive torque Tηmax is smaller than the required torque Treq.

  When it is determined that the additional drive torque Tηmax at which the determination result in step S118 is true (Yes) and the maximum engine efficiency ηmax is smaller than the required torque Treq, power generation by the motor 6 is not performed, and the process proceeds to step S20. In order to obtain the required torque Treq, the traveling by the driving force of the engine 2 or the assisting traveling by the driving force of the engine 2 and the electric motor 6 is performed. On the other hand, if the determination result of step S118 is false (No), the process proceeds to step S122.

When it is determined that the additional drive torque Tηmax is equal to or greater than the required torque Treq, it is considered that the engine efficiency η can be increased by operating the engine 2 with the additional drive torque Tηmax and generating electric power with the electric motor 6.
Therefore, first, in step S122, it is determined whether or not the difference between the additional drive torque Tηmax and the required torque Treq is larger than the maximum power generation drive torque Tgmax of the electric motor 6 (Tηmax−Treq> Tgmax). That is, since the electric motor 6 cannot exhibit the capacity equal to or greater than the maximum power generation driving torque Tgmax, it is determined here whether or not the electric motor 6 can exhibit the capacity equal to or greater than the maximum power generation driving torque Tgmax.

  If the determination result in step S122 is false (No) and it is determined that the difference between the additional drive torque Tηmax and the required torque Treq is equal to or less than the maximum power generation drive torque Tgmax of the electric motor 6, the process proceeds to step S124, where the additional drive torque Tηmax is By operating the engine 2, power generation by the electric motor 6 is performed. That is, as shown in FIG. 5, by adding the difference (ΔT = Tηmax−Treq) between the additional drive torque Tηmax and the required torque Treq to the required torque Treq, the additional drive torque Tηmax is made the additional drive torque T ′. The engine 2 is driven so as to have a driving torque T ′, and electric power generation running by the electric motor 6 is performed.

  On the other hand, if the determination result in step S122 is true (Yes) and it is determined that the difference between the additional drive torque Tηmax and the required torque Treq is greater than the maximum power generation drive torque Tgmax of the electric motor 6, the process proceeds to step S126 and the required torque By generating the maximum power generation driving torque Tgmax with respect to Treq and operating the engine 2, power generation by the electric motor 6 is performed. That is, as shown in FIG. 6, the maximum power generation driving torque Tgmax (ΔT = Tgmax) is added to the required torque Treq to obtain an additional driving torque T ′, and the engine 2 is driven to achieve this additional driving torque T ′. The power generation traveling by 6 is performed.

  As described above, in the control apparatus for the hybrid electric vehicle 1 according to the second embodiment of the present invention, the additional drive torque Tηmax having the maximum engine efficiency ηmax is compared with the required torque Treq, and the additional drive torque Tηmax is equal to or greater than the required torque Treq. If the difference between the additional drive torque Tηmax and the required torque Treq is less than or equal to the maximum power generation drive torque Tgmax of the motor 6, the additional drive torque T ′ is generated. The engine 2 is operated to generate power so that becomes the additional drive torque Tηmax.

Therefore, when charging the battery 18 while the vehicle is running, the engine 2 can efficiently generate power so that the maximum engine efficiency ηmax is obtained.
On the other hand, when the difference between the additional drive torque Tηmax and the required torque Treq is larger than the maximum power generation drive torque Tgmax of the electric motor 6, the engine 2 is set so that the additional drive torque T ′ becomes a value obtained by adding the maximum power generation drive torque Tgmax to the required torque Treq. They are driving and generating electricity.

Therefore, when charging the battery 18 while the vehicle is running, even if the maximum power generation driving torque Tgmax that can be absorbed by the electric motor 6 is small, the engine efficiency η is increased as much as possible, and the power generation by the engine 2 is made efficient. Can be done well.
Next, a third embodiment will be described.
Also in the third embodiment, the configuration of the main part of the control device of the hybrid electric vehicle 1 is as shown in FIG. 1, and the description thereof is omitted here.

Referring to FIG. 7, a travel control routine of the control device for the hybrid electric vehicle 1 according to the third embodiment executed by the vehicle ECU 22 is shown in a flowchart. Referring to FIGS. 8 and 9, the third embodiment is shown. A conceptual diagram of the control is shown on the engine efficiency map and the fuel consumption map, and will be described below with reference to FIGS.
In the third embodiment, unlike the first and second embodiments, in addition to the engine efficiency map, the vehicle ECU 22 includes an engine speed Ne, an engine torque T, and a fuel consumption amount Q as shown in FIG. The relationship is set and stored as a fuel consumption map, and power is generated by the electric motor 6 by operating the engine 2 in consideration of the engine efficiency η and the fuel consumption Q.

Specifically, as can be seen from the engine efficiency map and the fuel consumption map, the engine efficiency η improves as the engine torque T increases, while the fuel consumption Q tends to deteriorate. Here, the engine efficiency η and the fuel consumption Power consumption by the engine 2 is calculated with a comparative consideration of the consumption Q, which will be described below.
In FIG. 7, steps S10 to S16 are the same as those in FIG. 2 in the first embodiment, and a description thereof will be omitted.

  In step S218, it is determined whether or not the loss mechanical work WL is larger than the gain mechanical work Wg (engine power generation execution availability determination unit). Here, the gain mechanical work Wg means that the motor 6 is driven by the conversion work at the required engine efficiency ηr of the reduced fuel consumption corresponding to the improvement of the engine efficiency η (efficiency improvement Δη) and the generated generated power. This is the sum of the motor work (generated power x motor efficiency). On the other hand, as shown in FIG. 9, the lost mechanical work WL is, for example, an increase in fuel consumption (ΔQ between the required fuel consumption Qreq and the additional fuel consumption Q ′ with respect to the required torque Treq at the current engine speed Ne0. ) Is the conversion work in the required engine efficiency ηr.

  If the determination result of step S218 is true (Yes) and it is determined that the loss mechanical work WL is greater than the gain mechanical work Wg, the process proceeds to step S20, and the required torque Treq is obtained without generating power by the electric motor 6. As described above, traveling by the driving force of the engine 2 or assisting traveling by the driving force of the engine 2 and the electric motor 6 is performed. That is, when the loss mechanical work WL is larger than the gain mechanical work Wg, it is considered that the fuel efficiency Q is deteriorated although the engine efficiency η is improved. The power generation by the engine 2 is not performed.

  On the other hand, if the determination result in step S218 is false (No) and the loss machine work WL is less than or equal to the gain machine work Wg, that is, the gain machine work Wg is greater than or equal to the loss machine work WL, the process proceeds to step S122 and the subsequent steps. Driving is performed by the electric motor 6. In other words, when the gain mechanical work Wg is equal to or greater than the lost mechanical work WL, the power generation driving torque is added to the required engine efficiency ηr even if the additional fuel consumption Q ′ is larger than the required fuel consumption Qreq. It is considered that the additional engine efficiency η ′ is sufficiently high. In such a case, the engine 2 is driven to generate power by the electric motor 6.

Steps S122 to S126 are the same as those in the second embodiment described above with reference to FIG.
Thus, in the control apparatus for the hybrid electric vehicle 1 according to the third embodiment of the present invention, the gain mechanical work Wg based on the engine efficiency η is compared with the lost mechanical work WL based on the fuel consumption Q, and the gain mechanical work is compared. When Wg is greater than or equal to the loss mechanical work WL, the electric motor 6 is operated by the engine 2 to generate power, and when the loss mechanical work WL is greater than the gain mechanical work Wg, power generation by the engine 2 is not performed. I have to. Specifically, as in the second embodiment, when the difference between the additional drive torque Tηmax and the required torque Treq is equal to or less than the maximum power generation drive torque Tgmax of the electric motor 6, the additional drive torque T ′ becomes the additional drive torque Tηmax. The engine 2 is operated to generate power. On the other hand, when the difference between the additional drive torque Tηmax and the required torque Treq is larger than the maximum power generation drive torque Tgmax of the electric motor 6, the engine 2 is set so that the additional drive torque T ′ becomes a value obtained by adding the maximum power generation drive torque Tgmax to the required torque Treq. They are driving and generating electricity.

Therefore, when charging the battery 18 while the vehicle is running, power generation by the engine 2 can be performed more efficiently while preventing deterioration of fuel consumption.
Next, a fourth embodiment will be described.
The fourth embodiment is a modification of the third embodiment, and only the parts different from the third embodiment will be described below.

Referring to FIG. 10, a travel control routine of the control device for the hybrid electric vehicle 1 according to the fourth embodiment executed by the vehicle ECU 22 is shown in a flowchart. Hereinafter, FIG. 10 will be described with reference to FIGS. 8 and 9. Explain along.
In FIG. 10, steps S10 to S16 and steps S122 to S126 are the same as those in FIG. 7 in the third embodiment, and a description thereof will be omitted.

  In step S318, it is determined whether or not the difference or ratio (f (Wg, WL)) between the gain mechanical work Wg and the loss mechanical work WL is smaller than the threshold (engine power generation execution propriety determination means). Here, the threshold value is a value set according to the SOC. If the determination result is true (Yes) and it is determined that f (Wg, WL) is smaller than the threshold value, the process proceeds to step S20, in which the engine 2 generates the required torque Treq without generating power by the electric motor 6. Traveling by the driving force of the engine 2 or assisting traveling by the driving force of the engine 2 and the electric motor 6 is performed. On the other hand, if the determination result in step S318 is false (No) and f (Wg, WL) is greater than or equal to the threshold value, the process proceeds to step S122 and subsequent steps, and the engine 2 is driven to perform power generation running by the electric motor 6.

  Thus, also in the control apparatus of the hybrid electric vehicle 1 according to the fourth embodiment of the present invention, the gain mechanical work Wg based on the engine efficiency η is compared with the lost mechanical work WL based on the fuel consumption Q, and f ( When Wg, WL) is greater than or equal to the threshold value, the electric power is generated by operating the electric motor 6 in the engine 2, and when f (Wg, WL) is smaller than the threshold value, power generation by the engine 2 is not performed. .

Therefore, when charging the battery 18 while the vehicle is traveling, the power generation by the engine 2 can be performed more efficiently while preventing deterioration of fuel consumption, as in the case of the third embodiment.
Next, a fifth embodiment will be described.
The fifth embodiment is another modification of the third embodiment, and only the parts different from the third embodiment will be described below.

Referring to FIG. 11, a travel control routine of the control device for the hybrid electric vehicle 1 according to the fifth embodiment executed by the vehicle ECU 22 is shown in a flowchart. Referring to FIGS. 12 and 13, the fifth embodiment A conceptual diagram of the control is shown on the engine efficiency map, and will be described below with reference to FIGS.
In FIG. 11, steps S10 to S16 are the same as described above, and a description thereof will be omitted.

In step S30, it is determined whether or not the SOC is greater than the high SOC threshold (first predetermined value). If the determination result is true (Yes) and the SOC is greater than the high SOC threshold, the process proceeds to step S32. move on.
In step S32, the additional drive torque T ′ is obtained as described above, and when the difference between the additional drive torque T ′ and the required torque Treq is set to the additional torque optimum value ΔT0, the reduction addition is reduced to the additional torque optimum value ΔT0 or less. The torque ΔT1 is set as the additional torque ΔT (ΔT = ΔT1: ΔT1 ≦ ΔT0).

On the other hand, if the determination result in step S30 is false (No) and the SOC is equal to or lower than the high SOC threshold value, the process proceeds to step S34.
In step S34, it is determined whether or not the SOC is smaller than a low SOC threshold (second predetermined value). If the determination result is true (Yes) and the SOC is smaller than the low SOC threshold, the process proceeds to step S36. move on.

In step S36, the additional drive torque T ′ is obtained as described above, and the increased additional torque ΔT2 increased to the additional torque optimum value ΔT0 or more is set as the additional torque ΔT (ΔT = ΔT2: ΔT2 ≧ ΔT0).
On the other hand, if the determination result in step S34 is false (No) and the SOC is equal to or higher than the low SOC threshold value, the process proceeds to step S38. In this case, the additional torque optimum value ΔT0 is set as the additional torque ΔT (ΔT = ΔT0). ).

  When the additional torque ΔT is obtained in this way, the process proceeds to step S218, where it is determined whether or not the loss mechanical work WL is greater than the gain mechanical work Wg, and the loss mechanical work WL is greater than the gain mechanical work Wg. If it is determined, the process proceeds to step S20, and the traveling by the driving force of the engine 2 or the assisting traveling by the driving force of the engine 2 and the electric motor 6 is performed. That is, when the loss mechanical work WL is larger than the gain mechanical work Wg, it is considered that the fuel efficiency Q is deteriorated although the engine efficiency η is improved. The power generation by the engine 2 is not performed.

  On the other hand, if the determination result in step S218 is false (No) and the loss machine work WL is less than or equal to the gain machine work Wg, that is, the gain machine work Wg is greater than or equal to the loss machine work WL, the process proceeds to step S22 and the engine 2 is driven. Thus, power generation running by the electric motor 6 is performed. Specifically, the additional torque ΔT is added to the required torque Treq to be a new additional driving torque T ′, the engine 2 is operated with the additional driving torque T ′, the electric motor 6 is operated to generate electric power, and the battery 18 is charged.

  Thus, in the control apparatus for the hybrid electric vehicle 1 according to the fifth embodiment of the present invention, when the SOC is larger than the high SOC threshold, the reduction is reduced to the additional torque optimum value ΔT0 or less based on the SOC threshold. When the additional torque ΔT1 is the additional torque ΔT and the SOC is smaller than the low SOC threshold, the additional driving torque T ′ is set with the additional torque ΔT2 increased to the additional torque optimum value ΔT0 or more as the additional torque ΔT. ing.

Therefore, when the SOC is sufficiently higher than the high SOC threshold, it is not necessary to charge the battery 18, power generation by the engine 2 can be suppressed, and the SOC is lower than the low SOC threshold. Therefore, it is necessary to charge the battery 18 promptly, and power generation by the engine 2 can be enhanced.
Here, it is determined whether or not the loss mechanical work WL is larger than the gain mechanical work Wg in step S218, but the fifth embodiment may be a modification of the fourth embodiment. . That is, as shown in the flowchart in FIG. 14, step S318 is performed instead of step S218 in FIG. 11, and the difference or ratio (f (Wg, WL)) between the gain mechanical work Wg and the lost mechanical work WL (f (Wg, WL)) is less than the threshold value. You may make it discriminate | determine whether it is small. Further, the fifth embodiment may be a modification of the first embodiment or the second embodiment. That is, step S18 may be substituted for step S218 in FIG. 11 to determine whether or not the additional engine efficiency η ′ is smaller than the required engine efficiency ηr, or step S118 may be substituted for step S218. Further, it may be determined whether or not the additional drive torque Tηmax that provides the maximum engine efficiency ηmax is smaller than the required torque Treq.

Although the description of the control apparatus for a hybrid electric vehicle according to one embodiment of the present invention is finished above, the present invention is not limited to the above embodiment.
For example, in the above embodiment, the engine 2 is a diesel engine, but the engine type is not limited to this, and a gasoline engine or the like may be used.
Moreover, in the said embodiment, although the electric motor 6 was used as the permanent magnet type synchronous motor, the form of an electric motor is not restricted to this.

1 is an overall configuration diagram of a control apparatus for a hybrid electric vehicle according to an embodiment of the present invention. It is a flowchart which shows the traveling control routine in the control apparatus of the hybrid electric vehicle which concerns on 1st Example. It is a figure which shows the conceptual diagram of the control which concerns on 1st Example on an engine efficiency map. It is a flowchart which shows the traveling control routine of the control apparatus of the hybrid electric vehicle which concerns on 2nd Example. It is a figure which shows the conceptual diagram of the control which concerns on 2nd Example on an engine efficiency map. It is a figure which shows the conceptual diagram of the control which concerns on 2nd Example on an engine efficiency map. It is a flowchart which shows the traveling control routine of the control apparatus of the hybrid electric vehicle 1 which concerns on 3rd Example. It is a figure which shows the conceptual diagram of the control which concerns on 3rd Example on an engine efficiency map. It is a figure which shows the conceptual diagram of the control which concerns on 3rd Example on a fuel consumption map. It is a flowchart which shows the traveling control routine of the control apparatus of the hybrid electric vehicle which concerns on 4th Example. It is a flowchart which shows the traveling control routine of the control apparatus of the hybrid electric vehicle which concerns on 5th Example. It is a figure which shows the conceptual diagram of the control which concerns on 5th Example on an engine efficiency map. It is a figure which shows the conceptual diagram of the control which concerns on 5th Example on an engine efficiency map. It is a flowchart which shows the traveling control routine of the control apparatus of the hybrid electric vehicle which concerns on the modification of 5th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid electric vehicle 2 Engine 6 Electric motor 22 Vehicle ECU
32 Accelerator opening sensor (required torque detection means)
36 Rotational speed sensor (Rotational speed detection means)

Claims (9)

An engine capable of transmitting a driving force to a driving wheel of a vehicle, and an electric motor capable of transmitting the driving force to the driving wheel by power stored in a battery and generating electric power by the driving force of the engine and charging the battery, A control device for a hybrid electric vehicle having control means for controlling the engine and the electric motor based on a required driving torque obtained as a driving torque to be output by at least one of the engine and the electric motor according to a driving state of the vehicle In
Request torque detecting means for detecting the required drive torque;
A rotation speed detection means for detecting the engine rotation speed;
Based on the information from the required torque detection means and the information from the rotational speed detection means, at least the required drive torque from an engine efficiency map in which the degree of engine efficiency is set in advance according to the engine drive torque and the engine rotation speed. Engine efficiency calculating means for calculating the required engine efficiency of the corresponding engine;
Engine power generation feasibility determination means for determining whether or not power generation by the engine can be performed based on the required engine efficiency obtained by the engine efficiency calculation means,
The control device for a hybrid electric vehicle, wherein when the engine power generation feasibility determination unit determines that power generation by the engine can be performed, the engine causes the motor to perform a power generation operation. Corresponding to the required drive torque from an engine efficiency map in which the degree of engine efficiency is set in advance according to the engine drive torque and the engine rotational speed based on the information from the required torque detection means and the information from the rotational speed detection means Engine efficiency calculation means for calculating an additional engine efficiency corresponding to an additional drive torque obtained by adding a power generation drive torque for power generation of the electric motor to the required engine efficiency and the required drive torque of the engine;
Engine power generation feasibility determination means for comparing the required engine efficiency obtained by the engine efficiency calculation means and the additional engine efficiency to determine whether power generation by the engine is possible,
The control means, when it is determined by the engine power generation feasibility determination means that power generation by the engine can be performed, causes the engine to generate power based on the additional drive torque. 2. A control apparatus for a hybrid electric vehicle according to 1. The engine efficiency calculation means obtains a maximum engine efficiency as the additional engine efficiency,
The engine power generation execution feasibility determination unit determines whether power generation by the engine can be performed based on a difference between the required drive torque and an additional drive torque corresponding to the maximum engine efficiency,
The control means causes the motor to perform a power generation operation by the engine based on an additional driving torque that achieves the maximum engine efficiency when the engine power generation feasibility determination means determines that the engine can generate power. The control apparatus for a hybrid electric vehicle according to claim 2. When the power generation driving torque is the maximum power generation driving torque in the electric motor, and the maximum power generation driving torque is small with respect to the difference between the required driving torque and the additional driving torque that is the maximum engine efficiency,
4. The hybrid electric vehicle according to claim 3, wherein the control unit causes the engine to perform a power generation operation based on an additional drive torque that is a sum of the required drive torque and the maximum power generation drive torque. 5. Control device. Further, based on information from the required torque detection means and information from the rotation speed detection means, at least the fuel consumption map in which the degree of fuel consumption is set in advance according to the engine drive torque and the engine rotation speed is used. Fuel consumption calculating means for calculating the required fuel consumption of the engine corresponding to the required drive torque,
The engine power generation feasibility determination unit is configured to determine whether power generation by the engine is performed based on the required engine efficiency obtained by the engine efficiency calculation unit and the required fuel consumption amount obtained by the fuel consumption calculation unit. And
2. The hybrid electric vehicle according to claim 1, wherein when the engine power generation feasibility determination unit determines that power generation by the engine can be performed, the control unit causes the engine to generate electric power using the engine. Control device. Further, based on the information from the required torque detection means and the information from the rotation speed detection means, the request from a fuel consumption map in which the degree of fuel consumption is set in advance according to the engine drive torque and the engine rotation speed. Fuel consumption calculation means for calculating the required fuel consumption of the engine corresponding to the driving torque and the additional fuel consumption corresponding to the additional driving torque obtained by adding the power generation driving torque for power generation of the motor to the required driving torque. Prepared,
The engine power generation feasibility determination unit adds the mechanical driving gain that is the sum of the conversion work of the increase in engine efficiency by adding the power generation driving torque and the work of the motor by the generated power, and the power generation driving torque. Comparing the lost machine work, which is the conversion work of the increase in fuel consumption due to, to determine whether the engine can generate power,
The control means, when it is determined by the engine power generation feasibility determination means that power generation by the engine can be performed, causes the engine to generate power based on the additional drive torque. The control apparatus for a hybrid electric vehicle according to 2 or 3.   The engine power generation execution propriety determining means compares the difference or ratio between the gain mechanical work and the lost mechanical work with a threshold corresponding to the remaining charge rate of the battery to determine whether power generation by the engine can be performed. The hybrid electric vehicle control device according to claim 6, wherein the control device is a hybrid electric vehicle.   The control means, when the remaining charge rate of the battery is higher than a first predetermined value, causes the engine to perform a power generation operation based on an additional drive torque obtained by reducing the power generation drive torque. 8. The control apparatus for a hybrid electric vehicle according to claim 2, 3 or 6 or 7.   When the remaining charge rate of the battery is lower than a second predetermined value, the control means causes the engine to perform a power generation operation based on an additional drive torque obtained by increasing the power generation drive torque. 8. The control apparatus for a hybrid electric vehicle according to claim 2, 3 or 6 or 7.

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