JP2005110461A - Motor generator control method in parallel hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the change of a driving force by adjusting the driving force to a desired value and by absorbing the change of engine torque, even if change occurs in the engine torque. <P>SOLUTION: This motor generator control method is for a parallel hybrid vehicle provided with an engine that has a cylinder internal pressure sensor and a motor generator that assists power generation by an engine output or the engine output by battery electric power. Based on the detected opening of an accelerator, engine revolutions, and preset demanded torque map, driver-demanding torque is calculated (Steps S10, S11). Using the output value of the cylinder internal pressure sensor, the change of the cylinder internal pressure is detected (Step S12). Based on this detected cylinder internal pressure, the predicted amount of change of the engine torque or the predicted amount of change of the driving force is calculated (Steps S13, S14, S15). According to the predicted amount of change of the engine torque, the assist amount or the regeneration amount of the motor generator is feedback-controlled (Step S16). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for controlling a motor generator in a parallel hybrid vehicle. More specifically, even if an engine torque fluctuation amount occurs, the driving force can be adjusted to a desired value, and the engine torque fluctuation is absorbed to change the driving force. The present invention relates to a method for controlling a motor generator in a parallel hybrid vehicle that can suppress the above.

  The hybrid vehicle is equipped with an engine, a motor for driving the vehicle, and a battery for feeding the motor, and there are a series hybrid vehicle and a parallel hybrid vehicle depending on how the engine is used.

  The parallel hybrid vehicle is configured so that both the engine and the motor directly drive the wheels, and the motor assists the engine output and can run while charging the battery as a generator.

  On the other hand, the series hybrid vehicle is configured such that the wheels are driven by a motor and the engine drives only a generator, and the battery is charged and the motor is supplied with the generated power.

  Therefore, in the series hybrid vehicle, since the engine drives only the generator, even if the engine output fluctuates, this fluctuation can be detected by the amount of power generated by the motor. By making the amount of power supplied to the motor constant, it is possible to suppress fluctuations in the output of the motor and suppress deterioration in drivability of the vehicle.

  For example, Patent Document 1 discloses a technique for suppressing a decrease in driving force of a hybrid vehicle.

JP 2002-225578 A

  However, parallel hybrid vehicles that do not have a series hybrid system are not configured to directly detect engine output based on the amount of power generated by the motor, so even if engine torque fluctuations (output fluctuations) occur, fine adjustment of the driving force by the motors is possible. However, there has been a problem that the torque fluctuation of the engine directly leads to the fluctuation of the driving force, which may deteriorate drivability.

  The technique disclosed in Patent Document 1 does not disclose means for adjusting the driving force by detecting a change in the in-cylinder pressure that causes torque fluctuation in the engine output shaft.

  The present invention has been made in view of the above, and in a parallel hybrid vehicle, the driving force can be adjusted to a desired value even when the engine torque fluctuation amount occurs, and the driving force change is absorbed by absorbing the engine torque fluctuation. It is an object of the present invention to provide a method for controlling a motor generator in a parallel hybrid vehicle that can suppress the above.

  In order to solve the above-described problems and achieve the object, a method for controlling a motor generator in a parallel hybrid vehicle according to the present invention includes an engine having in-cylinder pressure detecting means for detecting in-cylinder pressure, and power generation or battery using the engine output. A method of controlling a motor generator in a parallel hybrid vehicle including a motor generator that assists the engine output by electric power, wherein an in-cylinder pressure change is detected using an output value of the in-cylinder pressure detecting means, and the detected A predicted engine torque change amount or a predicted driving force change amount is calculated based on the in-cylinder pressure change, and the assist amount or regenerative amount of the motor generator is fed back according to the calculated predicted engine torque change amount or predicted drive force change amount. It is characterized by controlling.

  Therefore, according to this invention, the in-cylinder pressure change that causes torque fluctuation in the engine output shaft is detected by the in-cylinder pressure detecting means, and the engine torque fluctuation amount or the driving force change amount is predicted based on the detected in-cylinder pressure value. The output of the motor generator can be adjusted by instantaneously feedback-controlling the torque instruction value of the motor generator that adjusts the driving force.

  According to the motor generator control method in the parallel hybrid vehicle according to the present invention, the driving force can be adjusted to a desired value even if the engine torque fluctuation amount occurs, and the engine torque fluctuation can be adjusted even in the parallel hybrid vehicle. Absorption can suppress the change in driving force. Thereby, the drivability of the parallel hybrid vehicle can be improved.

  Hereinafter, a case where the present invention is applied to a parallel diesel hybrid vehicle will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  First, a schematic configuration of a diesel hybrid vehicle (parallel hybrid vehicle) will be described with reference to FIG. Here, FIG. 2 is a schematic diagram showing a main part of the diesel hybrid vehicle.

  The diesel hybrid vehicle 10 is provided with a diesel engine (engine) 11 as a travel drive source. The diesel engine 11 includes an in-cylinder pressure sensor (in-cylinder pressure detecting means) (not shown) for detecting the in-cylinder pressure.

  The diesel engine 11 is controlled in fuel injection amount by a common rail fuel injection system (not shown). The intake air amount of the diesel engine 11 is detected by an air flow meter (not shown).

  The diesel engine 11 includes various sensors (not shown) such as a crank angle sensor that detects the rotational phase of the crankshaft, a rotational speed sensor that detects the engine rotational speed Ne, and an accelerator opening sensor that detects the accelerator opening degree Accp. ), A turbocharger (not shown), an exhaust gas purification device (not shown), and other known basic devices.

The driving force generated by the diesel engine 11 is transmitted to the wheels 13 via the transmission 12, the propeller shaft 16, the differential gear 15, and the drive shaft 14. The transmission 12 automatically and electrically controls a gear shift operation with an actuator in accordance with a traveling state.

  The diesel engine 11 is configured such that its fuel injection amount, intake air amount, and the like are controlled in order to output the requested engine torque commanded from the transmission 12. The required fuel injection amount of the diesel engine 11 is searched for a map from, for example, the engine speed Ne and the accelerator opening degree Accp, and fuel injection is executed based on the search result.

  Further, the diesel hybrid vehicle 10 is provided with a clutch (not shown) that performs contact / separation of power transmission between the diesel engine 11 and the transmission 12, and the contact / separation operation is electrically performed by an actuator according to the traveling state. It is designed to be automatically controlled.

  The motor generator 17 is connected via an inverter 19 to a battery 20 that is a chargeable / dischargeable secondary battery. Further, the motor generator 17 is configured to be able to take two operation states, a power running operation mode that functions as a motor that is a travel drive source, and a regenerative operation mode that functions as a generator.

  For example, the motor generator 17 receives power supplied from the battery 20 in the power running operation mode and generates power for driving the drive shaft 14 via the propeller shaft 16. In the regenerative operation mode, the motor generator 17 converts the driving force transmitted from the diesel engine 11 into electric power and charges the battery 20.

  Whether the motor generator 17 is operated in the power running mode or the regenerative operation mode is determined in consideration of the state of charge (SOC) of the battery 20.

  The diesel hybrid vehicle 10 configured as described above is controlled by an electronic control unit (ECU) (not shown). The electronic control unit (ECU) sets the fuel pressure, fuel injection timing, injection amount, and the like by the fuel injection system according to the operating state of the diesel engine 11, and calculates the combustion calculated based on the output of the in-cylinder pressure sensor. Fuel that feedback-controls the fuel injection amount, injection timing, etc. so that the value of a parameter (a parameter that represents the in-cylinder combustion state calculated based on the in-cylinder pressure) matches a target value that is determined according to the operating state Basic control such as injection control is performed.

  The diesel hybrid vehicle 10 is basically controlled by the electronic control unit (ECU) together with each component as follows, and can travel in various states. For example, in a relatively low speed state in which the diesel hybrid vehicle 10 starts traveling, the vehicle travels (EV traveling) by powering the motor generator 17 while the diesel engine 11 is stopped.

  Then, when the diesel hybrid vehicle 10 reaches a predetermined speed or load after the start of traveling, the diesel engine 11 is cranked and started using a starter (not shown), and the operation is shifted to the operation using the diesel engine 11.

  During steady operation, the diesel engine 11 is normally operated so as to generate an output substantially equal to the required power of the drive shaft 14. At this time, almost all of the output of the diesel engine 11 is transmitted to the drive shaft 14.

On the other hand, when the state of charge SOC of the battery 20 has dropped below a predetermined reference value, the diesel engine 11 is operated with an output that exceeds the required power of the drive shaft 14, and a part of the surplus power is a motor. It is regenerated as electric power by the generator 17 and used for charging the battery 20.

  Further, when the output torque of the diesel engine 11 is insufficient, the insufficient torque is assisted by driving the motor generator 17, and the necessary output torque can be ensured.

  The diesel hybrid vehicle 10 is also subjected to so-called eco-run (economy & ecology running) control in order to save fuel and reduce exhaust emissions. That is, for example, when the diesel hybrid vehicle 10 stops due to a signal waiting at an intersection or the like, the diesel engine 11 is automatically stopped under a predetermined stop condition, and then the predetermined restart condition (for example, when the accelerator pedal is depressed). ) Is also performed to restart the diesel engine 11.

  The above is the basic configuration and basic control operation of the diesel hybrid vehicle 10 according to the present invention.

  Next, a method for controlling the assist amount or the regenerative amount of the motor generator 17 which is a main part of the present invention will be described based on FIG. 1 with reference to FIG. Here, FIG. 1 is a flowchart showing a control method according to the present embodiment.

  First, the accelerator opening degree Accp is detected by an accelerator opening degree sensor (not shown), and the engine speed Ne is detected by a rotation speed sensor (not shown) (step S10).

  Then, using the detected accelerator opening degree Accp and the engine speed Ne, a driver request torque TEP is calculated from a predetermined request torque map (step S11).

  Note that the driver request torque in this request torque map is obtained in advance through experiments or the like, and is stored in the electronic control unit (ECU) as a numerical map using the accelerator opening degree Accp and the engine speed Ne.

  Next, the in-cylinder pressure of the diesel engine 11 is detected by an in-cylinder pressure sensor (not shown) (step S12). The reason for detecting the in-cylinder pressure is to detect a change in the in-cylinder pressure that causes a torque fluctuation in the engine output shaft and to predict an engine torque fluctuation amount or a driving force change.

  Then, in order to estimate the actual engine torque at the present time, an estimated engine torque value TEC is calculated from the detected in-cylinder pressure and a crank angle detected by a crank angle sensor (not shown) (step S13).

  Next, by obtaining the difference between the driver required torque TEP calculated in step S11 and the estimated engine torque value TEC calculated in step S13, the actual engine torque deviation that causes the engine torque fluctuation amount or the driving force change amount is obtained. A quantity (TEP-TEC) is calculated (step S14).

  Here, when the driver request torque TEP is larger than the estimated engine torque value TEC, the actual engine torque is insufficient, and it is necessary to torque assist the motor generator 17 for the shortage.

  On the other hand, when the driver request torque TEP is smaller than the engine torque estimated value TEC, the battery can be charged with surplus torque, and therefore it is necessary to regenerate by the motor generator 17.

  Therefore, next, the assist amount or the regeneration amount by the motor generator 17 is calculated (step S15). That is, the assist amount or the regenerative amount of the motor generator 17 is the actual engine torque deviation amount (TEP-TEC) applied to the output shaft of the motor generator 17, the relative gear ratio between the motor generator 17 and the engine crankshaft, It can be calculated by multiplying. For convenience of description space, motor generator 17 is indicated as MG in the mathematical expression in step S15.

  Then, by performing assist or regeneration by the motor generator 17 based on the calculated value in step S15 (step S16), the driving force can be adjusted to a desired value even if the engine torque fluctuation amount occurs.

  As described above, according to the motor generator control method for the parallel hybrid vehicle according to this embodiment, the in-cylinder pressure change that causes torque fluctuation in the engine output shaft is detected by the in-cylinder pressure sensor, and the in-cylinder pressure detection is performed. The output of the motor generator 17 can be adjusted by predicting the engine torque fluctuation amount or the driving force change amount based on the value and instantaneously feedback-controlling the torque instruction value of the motor generator 17 that adjusts the driving force.

  Therefore, the driving force can be adjusted to a desired value even when the engine torque fluctuation amount occurs, and even in a parallel hybrid vehicle, the engine torque fluctuation can be absorbed and the driving force change can be suppressed. Thereby, the drivability of the diesel hybrid vehicle 10 can be improved.

  In the above embodiment, the present invention has been described as being applied to the diesel hybrid vehicle 10, but the present invention is not limited to this and may be applied to a parallel hybrid vehicle having a gasoline engine.

  As described above, the motor generator control method in the parallel hybrid vehicle according to the present invention is useful for improving the drivability of the parallel hybrid vehicle, and adjusts the driving force to a desired value even if the engine torque fluctuation amount occurs. It is suitable for control that suppresses changes in driving force by absorbing engine torque fluctuations.

It is a flowchart which shows the control method which concerns on a present Example. It is a schematic diagram which shows the principal part of a diesel hybrid vehicle.

Explanation of symbols

10 Diesel hybrid vehicle (parallel hybrid vehicle)
11 Diesel engine (engine)
12 Transmission 13 Wheel 14 Drive shaft 15 Differential gear 16 Propeller shaft 17 Motor generator 19 Inverter 20 Battery Accp Accelerator opening Ne Engine speed TEP Driver required torque TEC Engine torque estimated value

Claims (1)

An engine having in-cylinder pressure detecting means for detecting in-cylinder pressure;
A motor generator for assisting the engine output by power generation or battery power by the engine output;
A method for controlling a motor generator in a parallel hybrid vehicle comprising:
A change in the in-cylinder pressure is detected using an output value of the in-cylinder pressure detecting means;
Calculating a predicted engine torque change amount or a predicted driving force change amount based on the detected in-cylinder pressure change;
A method for controlling a motor generator in a parallel hybrid vehicle, wherein feedback control is performed on an assist amount or a regeneration amount of the motor generator according to the calculated predicted engine torque change amount or predicted drive force change amount.

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