초록 ▼

In a hybrid car, or an electric motor-driven four-wheel-drive vehicle, in which an electric motor is driven directly by an output from a generator, vehicle running performance is enhanced. The output from the generator is controlled so as to maintain a generator torque in a range, in which the vehic

In a hybrid car, or an electric motor-driven four-wheel-drive vehicle, in which an electric motor is driven directly by an output from a generator, vehicle running performance is enhanced. The output from the generator is controlled so as to maintain a generator torque in a range, in which the vehicle does not stall. Specifically, a driving apparatus for the hybrid car includes a second generator 2 driven by an engine 1 for driving one pair of either front or rear wheels 14, 15, an electric motor 5 driven through directly receiving the output from the second generator 2 and driving the other pair of either the front or rear wheels 14, 15, and a four-wheel-drive control unit 6 controlling driving of the second generator 2 and the electric motor 5. When the engine 1 is in an overloaded condition, the four-wheel-drive control unit 6 limits the output of the second generator 2.

대표청구항 ▼

What is claimed is: 1. A driving apparatus for a hybrid car, comprising: a generator driven by an internal combustion engine drivingly rotating one pair of either front wheels or rear wheels; an electric motor driven through directly receiving an output from said generator and drivingly rotating th

What is claimed is: 1. A driving apparatus for a hybrid car, comprising: a generator driven by an internal combustion engine drivingly rotating one pair of either front wheels or rear wheels; an electric motor driven through directly receiving an output from said generator and drivingly rotating the other pair of either said front wheels or said rear wheels; and a control unit controlling the driving of said generator and said electric motor; wherein said control unit limits the output of said generator when said internal combustion engine is determined to be in an overloaded condition or a nearly overloaded condition and increase a field current of said electric motor when the output of said generator is limited. 2. The driving apparatus for a hybrid car according to claim 1, wherein said control unit limits the output of said generator when said internal combustion engine can run into the overloaded condition. 3. The driving apparatus for a hybrid car according to claim 1, wherein said control unit determines that said internal combustion engine is in the overloaded condition and limits the output of said generator when a generator torque given to said internal combustion engine from said generator exceeds an internal combustion engine permissible torque, of which said generator is allowed to deprive. 4. The driving apparatus for a hybrid car according to claim 1, wherein said control unit determines that said internal combustion engine is in the overloaded condition and limits the output of said generator when detonation of said internal combustion engine is detected. 5. The driving apparatus for a hybrid car according to claim 1, wherein said control unit comprising: means for calculating a target torque of said electric motor based on a driver's torque requirement and a car speed; means for calculating a target field current of said generator and a target field current of said electric motor from said target torque; means for providing an output of a control signal for field current control means of said generator based on the target field current corresponding to said generator; means for providing an output of a control signal for field current control means of said electric motor based on the target field current corresponding to said electric motor; and means for determining an overloaded condition of said internal combustion engine based on an operating condition of said generator and a predetermined generator permissible torque and providing an output of an output limitation request of said generator in accordance with said determination; wherein said means for calculating said target field current gives target field current for limiting the output of said generator in accordance with said output limitation request to said means for providing the output of a control signal for the field current control means of said generator, if said internal combustion engine is in the overloaded condition. 6. The driving apparatus for a hybrid car according to claim 5, wherein said control unit includes means for calculating an increased field current corresponding to said electric motor for compensating for an output drop of said electric motor due to the output limitation of said electric motor in accordance with said output limitation request and said means for calculating said target field current calculates, if said internal combustion engine is in the overloaded condition, a target field current for increasing the field current of said electric motor based on said increased field current and gives the target field current thus obtained to said means for providing the output of a control signal for the field current control means of said generator. 7. The driving apparatus for a hybrid car according to claim 5, wherein said generator permissible torque is a limit value, with which acceleration of the hybrid car can be retained at a predetermined level or more even when the generator torque is given to said internal combustion engine from said generator, and said means for providing the output of an output limitation request comprises: means for storing said generator permissible torque; means for calculating a generator torque to be given to said internal combustion engine from said generator based on an output voltage, an output current, and a speed of said generator; and means for providing an output of said output limitation request if said generator torque is compared with said generator permissible torque and said generator torque exceeds said generator permissible torque. 8. The driving apparatus for a hybrid car according to claim 1, wherein said generator is used exclusively for driving said electric motor when said electric motor is operated to give an assist drive and is provided independently of an auxiliary generator driven by said internal combustion engine. 9. The driving apparatus for a hybrid car according to claim 1, wherein said control unit comprising: means for calculating a target torque of said electric motor based on a driver's torque requirement and a car speed; means for calculating a target field current of said generator and a target field current of said electric motor from said target torque, respectively; means for providing an output of a control signal for field current control means of said generator based on the calculated target field current corresponding to said generator; means for providing an output of a control signal for field current control means of said electric motor based on the calculated target field current corresponding to said electric motor; and means for determining an overloaded condition of said internal combustion engine based on said torque requirement, an operating condition of said internal combustion engine, an operating condition of said generator, and an operating condition of auxiliary machinery driven by said internal combustion engine, and providing an output of an output limitation request of said generator in accordance with said determination; wherein said means for calculating said target field current of said generator gives the target field current for limiting the output of said generator in accordance with said output limitation request to said means for providing the output of a control signal for the field current control means of said generator, if said internal combustion engine is in the overloaded condition. 10. The driving apparatus for a hybrid car according to claim 9, wherein said control unit includes means for calculating an increased field current corresponding to said electric motor for compensating for an output drop of said electric motor due to the output limitation of said generator in accordance with said output limitation request and said means for calculating said target field current of said electric motor calculates, if said internal combustion engine is in the overloaded condition, a target field current for increasing the field current of said electric motor and gives the target field current thus obtained to said means for providing the output of a control signal for the field current control means of said electric motor. 11. The driving apparatus for a hybrid car according to claim 9, wherein said means for providing the output of an output limitation request comprising: means for calculating a generator torque given to said internal combustion engine from said generator based on an output voltage, an output current, and a speed of said generator; means for calculating an internal combustion engine permissible torque, of which said generator is allowed to deprive, based on said torque requirement that is an opening of an air control valve of said internal combustion engine or an amount of accelerator depression for controlling the opening of said air control valve, a speed of said internal combustion engine, and an operating condition of said auxiliary machinery; and means for providing an output of said output limitation request when said generator torque is compared with said internal combustion engine permissible torque and when said generator torque exceeds said internal combustion engine permissible torque. 12. The driving apparatus for a hybrid car according to claim 1, wherein said control unit comprising: means for calculating a target torque of said electric motor based on a driver's torque requirement and a car speed; means for calculating a target field current of said generator and a target field current of said electric motor from said target torque; means for providing an output of a control signal for field current control means of said generator based on the target field current corresponding to said generator; means for providing an output of a control signal for field current control means of said electric motor based on the target field current corresponding to said electric motor; and means for determining an overloaded condition of said internal combustion engine based on detection of detonation occurring in said internal combustion engine and providing an output of an output limitation request of said generator in accordance with said determination; wherein said means for calculating said target field current gives the target field current for limiting the output of said generator in accordance with said output limitation request to said means for providing the output of a control signal for the field current control means of said generator, if said internal combustion engine is in the overloaded condition. 13. The driving apparatus for a hybrid car according to claim 12, wherein said control unit includes means for calculating an increased field current corresponding to said electric motor for compensating for an output drop of said electric motor due to the output limitation of said electric motor in accordance with said output limitation request and said means for calculating said target field current calculates, if said internal combustion engine is in the overloaded condition, a target field current for increasing the field current of said electric motor based on said increased field current and gives the target field current thus obtained to said means for providing the output of a control signal for the field current control means of said electric motor. 14. The driving apparatus for a hybrid car according to claim 12, wherein said means for providing the output of an output limitation request determines whether or not detonation occurs in said internal combustion engine based on an output signal from a detonation sensor mounted in said internal combustion engine or a detonation occurrence signal from an internal combustion engine control unit controlling driving of said internal combustion engine and, in accordance with said determination, provides an output of said output limitation request. 15. The driving apparatus for a hybrid car according to claim 1, wherein said control unit comprising: means for calculating a target torque of said electric motor based on a driver's torque requirement and a car speed; means for calculating a target field current of said generator and a target field current of said electric motor from said target torque; means for providing an output of a control signal for field current control means of said generator based on the target field current corresponding to said generator; means for providing an output of a control signal for field current control means of said electric motor based on the target field current corresponding to said electric motor; and means for determining an overloaded condition of said internal combustion engine based on said driver's torque requirement and said car speed and providing an output of an output limitation request of said generator in accordance with said determination; wherein said means for calculating said target field current gives the target field current for limiting the output of said generator in accordance with said output limitation request to said means for providing the output of a control signal for the field current control means of said generator, if said internal combustion engine is in the overloaded condition. 16. The driving apparatus for a hybrid car according to claim 15, wherein said control unit includes means for calculating an increased field current corresponding to said electric motor for compensating for an output drop of said electric motor due to the output limitation of said electric motor in accordance with said output limitation request and said means for calculating said target field current calculates, if said internal combustion engine is in the overloaded condition, a target field current for increasing the field current of said electric motor based on said increased field current and gives the target field current thus obtained to said means for providing the output of a control signal for the field current control means of said electric motor. 17. The driving apparatus for a hybrid car according to claim 15, wherein said means for providing the output of an output limitation request comprising: means for calculating acceleration of the hybrid car based on the maximum speed of all speeds of said front wheels and said rear wheels; means for calculating an acceleration threshold value of the hybrid car based on said torque requirement that is an opening of an air control valve of said internal combustion engine or an amount of accelerator depression for controlling the opening of said air control valve; and means for providing an output of said output limitation request if said acceleration of the hybrid car is compared with said acceleration threshold value of the hybrid car and said acceleration of the hybrid car exceeds said acceleration threshold value of the hybrid car. 18. The driving apparatus for a hybrid car according to claim 1, wherein said control unit determines that said internal combustion engine is in the overloaded condition and limits the output of said generator when acceleration of the hybrid car exceeds an estimated acceleration of the hybrid car. 19. The driving apparatus for a hybrid car according to claim 1, wherein said control unit determines that said internal combustion engine is in the overloaded condition and limits the output of said generator when a generator torque given to said internal combustion engine from said generator exceeds a generator permissible torque, with which acceleration of the hybrid car can be retained at a predetermined level or more even when the generator torque is given to said internal combustion engine from said generator. 20. A hybrid car comprising: an internal combustion engine, as a driving source, which drivingly rotates one pair of either front wheels or rear wheels; and an electric motor, as another driving source, which drivingly rotates the other pair of either said front wheels or said rear wheels; a generator whose output is supplied directly to said electric motor for driving the latter, said generator being driven by said internal combustion engine, and the output from said generator is limited when said internal combustion engine is in an overloaded condition, and a control unit configured to increase a field current of said electric motor when the generator output is limited.