초록 ▼

In the case of the on setting of an eco switch signal ESW, when a torque demand Tr* is less than a good fuel consumption-assuring minimum torque Temin, the hybrid vehicle of the invention stops the operation of an engine and controls a motor MG2 to output a required torque for constant speed drive.

In the case of the on setting of an eco switch signal ESW, when a torque demand Tr* is less than a good fuel consumption-assuring minimum torque Temin, the hybrid vehicle of the invention stops the operation of an engine and controls a motor MG2 to output a required torque for constant speed drive. When the torque demand Tr* is not less than the good fuel consumption-assuring minimum torque Temin, on the other hand, the engine is driven at a drive point in a good fuel consumption range among drive points on an optimum fuel consumption operation curve to ensure output of the required torque for the constant speed drive. Such control enhances the fuel efficiency for the constant speed drive.

대표청구항 ▼

What is claimed is: 1. A hybrid vehicle, comprising: an internal combustion engine that is driven to output power for driving the hybrid vehicle; a motor that is driven to output power for driving the hybrid vehicle; a target vehicle speed setting unit that sets a target vehicle speed for constant

What is claimed is: 1. A hybrid vehicle, comprising: an internal combustion engine that is driven to output power for driving the hybrid vehicle; a motor that is driven to output power for driving the hybrid vehicle; a target vehicle speed setting unit that sets a target vehicle speed for constant speed drive of the hybrid vehicle; a mode selection unit that selectively activates either a normal drive mode or a fuel economy priority mode, which places the greater importance on fuel efficiency, in response to a driver's operation; a vehicle speed measurement unit that measures a vehicle speed; and a constant speed drive control module that, during normal constant speed drive with selective activation of the normal drive mode by the mode selection unit and with setting of the target vehicle speed by the target vehicle speed setting unit, controls the internal combustion engine and the motor to drive the internal combustion engine on a specific drive point curve satisfying a predetermined condition with possible intermittent operation and to make the measured vehicle speed approach to the set target vehicle speed, during fuel economy-priority constant speed drive with selective activation of the fuel economy priority mode by the mode selection unit and with setting of the target vehicle speed by the target vehicle speed setting unit, the constant speed drive control module controlling the internal combustion engine and the motor to drive the internal combustion engine in an efficient drive point range on the specific drive point curve satisfying the predetermined condition and to make the measured vehicle speed approach to the set target vehicle speed. 2. The hybrid vehicle in accordance with claim 1, wherein during the fuel economy-priority constant speed drive, when a vehicle speed difference between the measured vehicle speed and the set target vehicle speed is not less than a preset reference value, the constant speed drive control module controls the internal combustion engine and the motor to drive the internal combustion engine on the specific drive point curve satisfying the predetermined condition and to make the measured vehicle speed approach to the set target vehicle speed, during the fuel economy-priority constant speed drive, when the vehicle speed difference between the measured vehicle speed and the set target vehicle speed is less than the preset reference value, the constant speed drive control module controlling the internal combustion engine and the motor to drive the internal combustion engine in the efficient drive point range and to make the measured vehicle speed approach to the set target vehicle speed. 3. The hybrid vehicle in accordance with claim 1, wherein the constant speed drive control module controls the internal combustion engine and the motor to increase output of a constant speed driving force with an increase in vehicle speed difference between the measured vehicle speed and the set target vehicle speed, in order to cancel out the vehicle speed difference. 4. The hybrid vehicle in accordance with claim 3, wherein during the fuel economy-priority constant speed drive, when operation of the internal combustion engine in the efficient drive point range causes output of a driving force of not less than the constant speed driving force, the constant speed drive control module stops the operation of the internal combustion engine and controls the motor to output the constant speed driving force. 5. The hybrid vehicle in accordance with claim 4, wherein during the fuel economy-priority constant speed drive, when operation of the internal combustion engine in the efficient drive point range causes output of the driving force of not less than the constant speed driving force but when the motor is not allowed to output the constant speed driving force, the constant speed drive control module controls the motor to output an allowable level of driving force until output of the constant speed driving force is enabled from the internal combustion engine driven in the efficient drive point range. 6. The hybrid vehicle in accordance with claim 4, wherein during the fuel economy-priority constant speed drive, when operation of the internal combustion engine in the efficient drive point range causes output of the driving force of not less than the constant speed driving force but when the motor is not allowed to output the constant speed driving force, the constant speed drive control module controls the internal combustion engine to be driven in the efficient drive point range. 7. The hybrid vehicle in accordance with claim 1, wherein the predetermined condition is that the internal combustion engine is driven at an efficient drive point among drive points of outputting an identical power, and in the efficient drive point range, the internal combustion engine is driven at a rotation speed of not lower than a preset level. 8. The hybrid vehicle in accordance with claim 1, further comprising an electric power-mechanical power input output mechanism that is connected with an output shaft of the internal combustion engine and with an axle of the hybrid vehicle and outputs at least part of the output power of the internal combustion engine to the axle through input and output of electric power and mechanical power. 9. The hybrid vehicle in accordance with claim 8, wherein the electric power-mechanical power input output mechanism has: a three shaft power input output module that is linked to three shafts, the output shaft of the internal combustion engine, the axle, and a rotating shaft, and inputs and outputs power from and to a residual one shaft based on powers input from and output to any two shafts among the three shafts; and a generator that inputs and outputs power from and to the rotating shaft. 10. The hybrid vehicle in accordance with claim 8, wherein the electric power-mechanical power input output mechanism has a pair-rotor motor that has a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the axle and is driven to rotate through relative rotation of the first rotor to the second rotor. 11. The hybrid vehicle comprising: an internal combustion engine that is driven to output power for driving the hybrid vehicle; a motor that is driven to output power for driving the hybrid vehicle; a target vehicle speed setting unit that sets a target vehicle speed for constant speed drive of the hybrid vehicle; a mode selection unit that selects a control mode, in response to a driver's operation, wherein the mode selection unit selects the control mode among plural options including a normal drive mode where the internal combustion engine is driven on a specific drive point curve satisfying a predetermined condition, a fuel economy priority mode where the internal combustion engine is driven in an efficient drive point range on the specific drive point curve satisfying the predetermined condition, and a noise reduction mode where the internal combustion engine is driven in a noise reduction drive point range satisfying a noise reduction condition for preventing occurrence of certain noise; a vehicle speed measurement unit that measures a vehicle speed; and a constant speed drive control module that, in the case of setting the target vehicle speed by the target vehicle speed setting unit, controls the internal combustion engine and the motor in the selected control mode to make the measured vehicle speed approach to the set target vehicle speed with intermittent operation of the internal combustion engine. 12. The hybrid vehicle in accordance with claim 11, wherein in the case of selection of the fuel economy priority mode, when a vehicle speed difference between the measured vehicle speed and the set target vehicle speed is less than a preset reference value, the constant speed drive control module controls the internal combustion engine and the motor to drive the internal combustion engine on the specific drive point curve satisfying the predetermined condition and to make the measured vehicle speed approach to the set target vehicle speed, in the case of selection of the fuel economy priority mode, when the vehicle speed difference between the measured vehicle speed and the set target vehicle speed is not less than the preset reference value, the constant speed drive control module controlling the internal combustion engine and the motor to drive the internal combustion engine in the efficient drive point range and to make the measured vehicle speed approach to the set target vehicle speed. 13. The hybrid vehicle in accordance with claim 11, wherein in the case of selection of the noise reduction mode, when a vehicle speed difference between the measured vehicle speed and the set target vehicle speed is less than a preset reference value, the constant speed drive control module controls the internal combustion engine and the motor to drive the internal combustion engine on the specific drive point curve satisfying the predetermined condition and to make the measured vehicle speed approach to the set target vehicle speed, in the case of selection of the noise reduction mode, when the vehicle speed difference between the measured vehicle speed and the set target vehicle speed is not less than the preset reference value, the constant speed drive control module controlling the internal combustion engine and the motor to drive the internal combustion engine in the noise reduction drive point range satisfying the noise reduction condition and to make the measured vehicle speed approach to the set target vehicle speed. 14. The hybrid vehicle in accordance with claim 11, further comprising an accumulator unit that is capable of inputting and outputting electric power from and to the motor, wherein when *a state of charge of the accumulator unit is in a predetermined range, the constant speed drive control module controls the internal combustion engine and the motor in the control mode selected by the mode selection unit to make the measured vehicle speed approach to the set target vehicle speed, when the state of charge of the accumulator unit is out of the predetermined range, the constant speed drive control module controlling the internal combustion engine and the motor in the normal drive mode, regardless of the control mode selected by the mode selection unit, to make the measured vehicle speed approach to the set target vehicle speed. 15. The hybrid vehicle in accordance with claim 11, wherein the predetermined condition is that the internal combustion engine is driven at an efficient drive point among drive points of outputting an identical power, in the efficient drive point range, the internal combustion engine is driven at a rotation speed of not lower than a preset level, and the noise reduction condition is omission of a low rotation speed--high torque operation range of the internal combustion engine from the predetermined condition. 16. The hybrid vehicle in accordance with claim 11, further comprising an electric power-mechanical power input output mechanism that is connected with an output shaft of the internal combustion engine and with an axle of the hybrid vehicle and outputs at least part of the output power of the internal combustion engine to the axle through input and output of electric power and mechanical power. 17. The hybrid vehicle in accordance with claim 16, wherein the electric power-mechanical power input output mechanism has: a three shaft power input output module that is linked to three shafts, the output shaft of the internal combustion engine, the axle, and a rotating shaft, and inputs and outputs power from and to a residual one shaft based on powers input from and output to any two shafts among the three shafts; and a generator that inputs and outputs power from and to the rotating shaft. 18. The hybrid vehicle in accordance with claim 16, wherein the electric power-mechanical power input output mechanism has a pair-rotor motor that has a first rotor connected to the output haft of the internal combustion engine and a second rotor connected to the axle and is driven to rotate through relative rotation of the first rotor to the second rotor. 19. A control method of a hybrid vehicle, the hybrid vehicle having: an internal combustion engine that is driven to output power for driving the hybrid vehicle; a motor that is driven to output power for driving the hybrid vehicle; a target vehicle speed setting switch that is operated to set a target vehicle speed for constant speed drive of the hybrid vehicle; and a mode selection switch that is operated by a driver to select either a normal drive mode or a fuel economy priority mode, which places the greater importance on fuel efficiency, in the case of selection of the normal drive mode by the driver's operation of the mode selection switch and setting of the target vehicle speed by the target vehicle speed setting switch, the control method controlling the internal combustion engine and the motor to drive the internal combustion engine on a specific drive point curve satisfying a predetermined condition with possible intermittent operation and to make the measured vehicle speed approach to the set target vehicle speed, in the case of selection of the fuel economy priority mode by the driver's operation of the mode selection switch and setting of the target vehicle speed by the target vehicle speed setting switch, the control method controlling the internal combustion engine and the motor to drive the internal combustion engine in an efficient drive point range on the specific drive point curve satisfying the predetermined condition and to make the measured vehicle speed approach to the set target vehicle speed. 20. A control method of a hybrid vehicle, the hybrid vehicle having: an internal combustion engine that is driven to output power for driving the hybrid vehicle; a motor that is driven to output power for driving the hybrid vehicle; a target vehicle speed setting switch that is operated to set a target vehicle speed for constant speed drive of the hybrid vehicle; and a mode selection switch that is operated by a driver to select a control mode, the mode selection switch selects the control mode among plural options including a normal drive mode where the internal combustion engine is driven on a specific drive point curve satisfying a predetermined condition, a fuel economy priority mode where the internal combustion engine is driven in an efficient drive point range on the specific drive point curve satisfying the predetermined condition, and a noise reduction mode where the internal combustion engine is driven in a noise reduction drive point range satisfying a noise reduction condition for preventing occurrence of certain noise, in the case of setting the target vehicle speed by the target vehicle speed setting switch, the control method controlling the internal combustion engine and the motor in the control mode selected by the driver's operation of the mode selection switch to make the measured vehicle speed approach to the set target vehicle speed with intermittent operation of the internal combustion engine.