A hybrid vehicle includes: an engine; a first motor; a planetary gear having three rotary elements that are connected respectively to a rotary shaft of the first motor, an output shaft of the engine, and a drive shaft coupled to an axle such that on a collinear diagram, the rotary shaft, the output shaft, and the drive shaft are arranged in that order; a second motor; a first inverter configured to drive the first motor; a second inverter configured to drive the second motor; a battery capable of exchanging power with the first and second motors via the first and second inverters; and an electronic control unit configured to control the engine such that a rotation speed of the engine increases at a predetermined time when the engine is operative, respective gates of the first and second inverters are both blocked, and an accelerator is ON.

A fuel pump system of a hybrid vehicle is provided. The fuel pump system prevents a fuel pump from continuing to operate when fuel is exhausted, whereby the fuel pump may be damaged. The pressure of fuel is measured in response to exhaustion of fuel, and when the pressure of fuel is low, fuel is circulated within the fuel pump instead of being supplied to the engine side, thereby preventing the fuel pump from being stuck due to frictional heat.

An apparatus for controlling a hybrid vehicle may include an engine that generates driving torque by combustion of fuel; an integrated starter-generator that starts the engine and generates electrical energy by selectively operating as a power generator; a drive motor that supports the power of the engine and generates electrical energy by selectively operating as a power generator; a battery that charges with the electrical energy generated by the integrated starter-generator and the drive motor; a nitrogen oxide purification device (LNT) that purifies nitrogen oxide included in exhaust gas exhausted from the engine; and a controller that controls engine torque by calculating a target engine torque for regenerating the nitrogen oxide purification device, supports the engine torque through the integrated starter-generator or the drive motor when a driving torque necessary for driving is greater than the target engine torque at a regeneration mode of the nitrogen oxide purification device, and performs regenerative braking the driving torque through the integrated starter-generator or the drive motor when the driving torque is less than the target engine torque.

An apparatus for activating a catalyst of a hybrid vehicle may include: an engine including a plurality of cylinders, at least one intake valve and at least one exhaust valve, a variable valve apparatus adjusting lift and opening timing of the intake valve and exhaust valve, an integrated starter-generator, a driving information detector detecting driving information including a vehicle speed, a displacement of an accelerator pedal, and a displacement of a brake pedal, an exhaust gas purification apparatus, and a controller cutting off fuel supplied into the cylinder, opening the exhaust valve by using the variable valve apparatus during a suction stroke, and generating electrical energy through the integrated starter-generator when a regenerative braking condition of a hybrid vehicle is satisfied from the driving information detected by the driving information detector.

A method for controlling a vehicle power train that includes a heat engine connected to the transmission of the vehicle by a clutch controlled between an open position and a closed position of the transmission by a computer of the transmission exchanging information with a computer of the heat engine. The method includes sending, in order to shut down the engine before the clutch is opened when the vehicle is in motion, the kinematic chain being closed and the injection interrupted, a message from the computer of the transmission to the computer of the engine at a first moment in time so as to synchronize an opening of the clutch and the closure of an air flap of the engine at a second moment in time subsequent to the first moment.

A controller is capable of controlling a coupled engine running mode, in which an engine is coupled to wheels and an engine brake is activated by driven rotation of the engine, and a coasting mode, in which an engine brake force is reduced with respect to that in the coupled engine running mode with mode with the engine brake on, and starts the coasting mode on the basis of the steering angle of a steering member. The controller starts the execution of a first coasting mode when the steering angle is equal to or less than a preset upper limit value and starts the execution of a second coasting mode when the steering angle is greater than the upper limit value. In the first coasting mode, the engine rotation is stopped, and in the second coasting mode, the engine remains rotating.

A system and method for controlling switching between driving modes of a hybrid electric vehicle are provided. In particular, driving mode switching is performed from an electric vehicle (EV) mode to a hybrid electric vehicle (HEV) mode under a condition in which the fuel injection compensation amount when an engine is first started is minimized The driving mode switching from an EV mode to an HEV mode is performed before gear shift from a lower gear to a higher gear is completed (e.g., before the speed of a motor is reduced) during accelerated driving of the vehicle to minimize the fuel injection compensation amount when an engine is first started, thereby improving fuel efficiency.

Methods and systems are provided for a fuel system in a hybrid vehicle. In one example, a method includes activating a fuel pump in a fuel tank included in the hybrid vehicle responsive to a refueling event with a level of residual fuel higher than a fill threshold. By activating the fuel pump, residual fuel in the fuel tank is mixed with newly received fuel in the refueling event enabling improved combustion in a subsequent engine-on condition.

An apparatus for controlling a hybrid vehicle may include an engine that generates driving torque by combustion of fuel; an integrated starter-generator that starts the engine and generates electrical energy by selectively operating as a power generator; a drive motor that supports the power of the engine and generates electrical energy by selectively operating as a power generator; a battery that charges with the electrical energy generated by the integrated starter-generator and the drive motor; a nitrogen oxide purification device (LNT) that purifies nitrogen oxide included in exhaust gas exhausted from the engine; and a controller that controls engine torque by calculating a target engine torque for regenerating the nitrogen oxide purification device, supports the engine torque through the integrated starter-generator or the drive motor when a driving torque necessary for driving is greater than the target engine torque at a regeneration mode of the nitrogen oxide purification device, and performs regenerative braking the driving torque through the integrated starter-generator or the drive motor when the driving torque is less than the target engine torque.

A method for operating a drive system having at least one drive engine for a motor vehicle, having the following: carrying out an acceleration monitoring of the motor vehicle, a changeover to an alternative monitoring being made when the acceleration monitoring can no longer carry out a reliable monitoring, and, in the alternative monitoring, an engine rotational speed being limited to a maximum permissible engine rotational speed; and ascertaining the maximum permissible rotational speed as a function of a rotational speed specification specified by a driver's request.