When a brake is turned on during travel of a hybrid vehicle, a required braking force required for a drive shaft is set based on a brake depression amount, a base rotation speed of an engine is set based on the required braking force, a shift stage is set based on the base rotation speed and a vehicle speed, a target rotation speed of the engine is set based on the shift stage and the vehicle speed, and the engine, the first motor, and the second motor are controlled such that the engine operates at the target rotation speed and the required braking force acts on the drive shaft.

A vehicle control system for preventing malfunction of the clutch for selectively connecting the engine with the power train. The vehicle control system is applied to a vehicle having an engine, a motor disposed on a power train, and a clutch interposed therebetween. In order to prevent a malfunction of the clutch, the vehicle control system is configured to engage the clutch while causing a slip but without starting the engine if the engine has not yet been started.

A controller controls an electric motor such that a pulsation compensation torque corresponding to a pulsation component of a torque of an internal combustion engine, which appears in a drive shaft, is supplied to the drive shaft as a damping torque for suppressing vibrations of a hybrid vehicle. A determination is made as to whether a torque of the electric motor, excluding the pulsation compensation torque, is smaller than a predetermined value. When it is determined that the torque excluding the pulsation compensation torque is smaller than the predetermined value, the controller selects one mode having a highest energy efficiency of the hybrid vehicle from among a plurality of modes, and controls the internal combustion engine and the electric motor based on the selected mode.

A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine and configured to start the engine from an inactive state. A high-voltage battery powers both of the first electric machine and the second electric machine over a high-voltage bus. The vehicle further includes a controller programmed to issue a command to start the engine using the second electric machine in response to a threshold acceleration demand following a period of reduced acceleration demand.

A hybrid vehicle includes an engine, a first motor, a planetary gear mechanism, a second motor, a battery, and an electronic control unit. The electronic control unit is configured to: set a shift stage based on a depression amount of an accelerator and a vehicle speed or a driver's operation; set a base driving force based on the degree of the depression amount of the accelerator, the vehicle speed, and a target rotation speed; set a correction driving force such that the correction driving force increases with an increase in elapsed time after upshifting or an increase in the vehicle speed after upshifting when the shift stage upshifts; and control the engine, the first motor, and the second motor such that a driving force obtained by correcting the base driving force using the correction driving force is output to the drive shaft.

The present disclosure provides a hybrid electric vehicle, a drive control method and a drive control device of a hybrid electric vehicle. The drive control method includes: obtaining a current gear position of the hybrid electric vehicle and a current electric charge level of a power battery; determining whether the vehicle is within a speed start-stop interval according to the current gear position of the hybrid electric vehicle and the current electric charge level of the power battery; obtaining a slope of a road on which the vehicle is driving and a current speed of the hybrid electric vehicle, if the vehicle is within a speed start-stop interval; and controlling a working state of an engine and/or a motor of the hybrid electric vehicle according to the slope of the road on which the vehicle is driving and the current speed of the vehicle.

A hybrid vehicle includes powertrain components such as an engine, an automatic transmission, and a traction motor selectively coupled to the engine via a clutch and to the transmission. At least one controller is programmed to control these powertrain components. The vehicle is driven over a drive cycle that includes multiple engine starts and transmission gear shifts. An amount of fuel consumption used during these engine starts and transmissions gear shifts is stored on an on-board storage device. Subsequently, the engine is inhibited from starting and the transmission is inhibited from shifting gears based on the amount of fuel consumption associated with the engine starts and transmission gear shifts performed during the drive cycle as recalled from the storage device.

A remaining fuel amount warning device for a vehicle, the remaining fuel amount warning device giving a warning that an amount of fuel remaining in a fuel tank is smaller than a predetermined value on the basis of output of a fuel gauge measuring the remaining fuel amount, includes combustion state changing device for changing the combustion state of an engine. When the remaining fuel amount becomes smaller than the predetermined value, the remaining fuel amount warning device performs remaining amount warning control that produces vibration different than during normal operation by changing the combustion state of the engine by the combustion state changing device. A starter switch for starting the engine is made to serve also as a warning acknowledging button for stopping the remaining amount warning control for a predetermined time on the basis of an operation by an occupant.

A vehicle includes a hybrid powertrain. The hybrid powertrain includes an engine and an electric machine. In response to a loss of controllability of the electric machine, a controller is programmed to operate the powertrain in a limited operating mode. In the limited operating mode, the powertrain is controlled so that a speed of the engine is within a speed range such that the electric machine generates a current to charge a traction battery. In response to a loss of communication with a power inverter that controls the electric machine, the powertrain is controlled so that the speed of the engine is within the speed range and the current flowing to the traction battery is monitored. If the current flow is above a threshold, then the limited operating mode is entered.

When a kickdown switch is turned off, a target rotation speed of an engine is set on the basis of a vehicle speed and a gear and the engine, the first motor, and the second motor are controlled such that the smaller driving force of an upper-limit driving force based on the target rotation speed and a required driving force is output to a drive shaft and the engine rotates at the target rotation speed. On the other hand, when the kickdown switch is turned on, the target rotation speed is set to be higher than that when the kickdown switch is turned off on the basis of the vehicle speed and the gear and the engine, the first motor, and the second motor are controlled such that the required driving force is output to the drive shaft and the engine rotates at the target rotation speed.