Mode change control system for hybrid vehcile
First Claim
1. A control system of a hybrid vehicle including an engine, a motor/generator, a battery operable to provide the motor/generator with electric power and to receive and store electric power regenerated by the motor/generator, a first clutch disposed between the engine and the motor/generator, and at least one driving wheel, the control system comprising:
- a controller configured to;
select a drive mode wherein the drive mode comprises at least one of an electric drive mode, in which the first clutch is released and power transmission is made only between the motor/generator and the at least one driving wheel, and a hybrid drive mode, in which the first clutch is engaged and power transmission is made between at least the engine and the motor/generator and the at least one driving wheel, wherein the hybrid drive mode is selected by initiating a mode change from the electric drive mode to the hybrid drive mode when a battery charge state of the battery becomes lower than a first set battery charge state and wherein the electric drive mode is selected by initiating a mode change from the hybrid drive mode to the electric drive mode when the battery charge state becomes higher than or equal to a second set battery charge state, wherein an initial value of the second set battery charge state is higher than the first set battery charge state;
determine a vehicle driving condition when the battery charge state of the battery becomes lower than the second set battery charge state; and
reduce the second set battery charge state to a lower value than the initial value when the vehicle driving condition is judged to be a low load drive condition in which a regenerative braking is carried out under the battery charge state during the hybrid drive mode such that the electric drive mode is selected, initiating the mode change from the hybrid drive mode to the electric drive mode at the lower value of the second set battery charge state.
1 Assignment
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Accused Products
Abstract
During vehicle drive under an EV mode, a battery charge state SOC becomes smaller than a SOC(L) at time t0. As a result, EV→HEV mode change is carried out. After time t1, deceleration is desired, and an accelerator opening APO is kept at 0. At time t3, the SOC increases and becomes greater than or equal to a SOC(H) by the HEV mode. In this case, after time t1 of release of an accelerator pedal, the SOC(H) is cleared at time t2 at which a vehicle operating condition is judged to be a low load drive condition in which a motor/generator performs regenerative braking. By making a judgment of HEV→EV mode change based on the SOC(L) instead of the SOC(H), the HEV→EV mode change is carried out before time t3. A regenerative braking time Δt with the engine dragged is therefore shortened, and a regenerative braking time with no-engine drag can be correspondingly lengthened, improving an energy recovery performance.
37 Citations
18 Claims
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1. A control system of a hybrid vehicle including an engine, a motor/generator, a battery operable to provide the motor/generator with electric power and to receive and store electric power regenerated by the motor/generator, a first clutch disposed between the engine and the motor/generator, and at least one driving wheel, the control system comprising:
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a controller configured to; select a drive mode wherein the drive mode comprises at least one of an electric drive mode, in which the first clutch is released and power transmission is made only between the motor/generator and the at least one driving wheel, and a hybrid drive mode, in which the first clutch is engaged and power transmission is made between at least the engine and the motor/generator and the at least one driving wheel, wherein the hybrid drive mode is selected by initiating a mode change from the electric drive mode to the hybrid drive mode when a battery charge state of the battery becomes lower than a first set battery charge state and wherein the electric drive mode is selected by initiating a mode change from the hybrid drive mode to the electric drive mode when the battery charge state becomes higher than or equal to a second set battery charge state, wherein an initial value of the second set battery charge state is higher than the first set battery charge state; determine a vehicle driving condition when the battery charge state of the battery becomes lower than the second set battery charge state; and reduce the second set battery charge state to a lower value than the initial value when the vehicle driving condition is judged to be a low load drive condition in which a regenerative braking is carried out under the battery charge state during the hybrid drive mode such that the electric drive mode is selected, initiating the mode change from the hybrid drive mode to the electric drive mode at the lower value of the second set battery charge state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A controller for a hybrid vehicle including an engine, a motor/generator, a battery operable to provide the motor/generator with electric power and to receive and store electric power regenerated by the motor/generator, a first clutch disposed between the engine and the motor/generator, and at least one driving wheel, the controller comprising:
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means for selecting a drive mode wherein the drive mode comprises at least one of an electric drive mode, in which the first clutch is released and power transmission is made only between the motor/generator and the at least one driving wheel, and a hybrid drive mode, in which the first clutch is engaged and power transmission is made between at least the engine and the motor/generator and the at least one driving wheel, wherein the selecting means includes; means for initiating a mode change from the electric drive mode to the hybrid drive mode when a battery charge state of the battery becomes lower than a first set battery charge state; and means for initiating a mode change from the hybrid drive mode to the electric drive mode when the battery charge state becomes higher than or equal to a second set battery charge state, wherein an initial value of the second set battery charge state is higher than the first set battery charge state; means for determining a vehicle driving condition when the battery charge state of the battery becomes lower than the second set battery charge state; and means for reducing the second set battery charge state to a lower value than the initial value when the vehicle driving condition is judged to be a low load drive condition in which a regenerative braking is carried out under the battery charge state during the hybrid drive mode such that the means for selecting a drive mode selects the electric drive mode, initiating a mode change from the hybrid drive mode to the electric drive mode at the lower value of the second set battery charge state.
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11. A control method of a hybrid vehicle including an engine, a motor/generator, a battery operable to provide the motor/generator with electric power and to receive and store electric power regenerated by the motor/generator, a first clutch disposed between the engine and the motor/generator, and at least one driving wheel, the control method comprising:
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selecting a drive mode wherein the drive mode comprises at least one of an electric drive mode, in which the first clutch is released and power transmission is made only between the motor/generator and the at least one driving wheel, and a hybrid drive mode, in which the first clutch is engaged and power transmission is made between at least the engine and the motor/generator and the at least one driving wheel, wherein selecting the drive mode includes; deciding to make a mode change from the electric drive mode to the hybrid drive mode when a battery charge state of the battery becomes lower than a first set battery charge state; and deciding to make a mode change from the hybrid drive mode to the electric drive mode when the battery charge state becomes higher than or equal to a second set battery charge state, wherein an initial value of the second set battery charge state is higher than the first set battery charge state; determining a vehicle driving condition when the battery charge state of the battery become lower than the second set battery charge state; reducing the second set battery charge state to a lower value than the initial value when the vehicle driving condition is judged to be a low load drive condition in which a regenerative braking is carried out under the battery charge state during the hybrid drive mode; and deciding to make the mode change to the electric drive mode from the hybrid drive mode based on the lower value of the second set battery charge state when the vehicle driving condition is judged to be the low load drive condition. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification