A method for protecting a dual mass flywheel DMF, by detecting, when the engine in running, that the DMF is entering into resonance, the DMF being arranged between an internal combustion engine and a gearbox of a vehicle, comprising the following steps: • Determining the average rotational speed (Vvil.sub.moy) of the crankshaft, over time, over a predetermined given period, as a first parameter constituting a risk of the DMF entering into resonance, • Measuring the maximum instantaneous rotational speed and the minimum instantaneous rotational speed of the crankshaft, the difference defining the maximum amplitude (Amp.sub.Vvil) of the rotational oscillations of the crankshaft, over the period, as a second parameter constituting a risk of the DMF entering into resonance, • Detecting when the DMF is entering into resonance from a determined combination of values of the first and second parameters, over the period, • limiting or cutting off the fuel injection in the cylinders after said detection.

A power train device of a vehicle includes an engine and an automatic transmission. The automatic transmission is configured such that in a neutral state, multiple ones of multiple rotary elements forming a power transmission path other than a rotary element coupled to an input member and a rotary element coupled to an output member are in a non-restraining state. The multiple ones of the multiple rotary elements include a rotary element of a predetermined brake among multiple friction fastening elements, and the predetermined brake is fastened before a fuel supply upon an engine start.

A hybrid vehicle includes a connecting/disconnecting clutch disposed between an engine and an electric motor, an automatic transmission including an input clutch, a starting clutch disposed between the electric motor and the automatic transmission, and a control apparatus for executing an engine-start control operation for starting the engine, by igniting the engine after increasing a rotational speed of the engine by a torque of the electric motor while placing the connecting/disconnecting clutch into an engaged state. In process of the engine-start control operation that is executed when the hybrid vehicle is in a stopped state with the starting clutch being in a released state, the control apparatus places the input clutch in an engaged state until the rotational speed of the engine exceeds a predetermined speed value, and switches the input clutch to a released state after the rotational speed of the engine has exceeded the predetermined speed value.

A hybrid drive includes an internal combustion engine, an electrical machine, at least one torsional vibration damper, and an electronic control unit. The torsional vibration damper is designed for optimal vibration damping during operation of the internal combustion engine with the full number of cylinders of the internal combustion engine switched-on in internal-combustion-engine mode. The electronic control unit is further designed such that, in purely electric-motor mode where no cylinders are switched on, the electrical machine simulates the cylinder-ignition-dependent torque excitations of the switched-off internal combustion engine substantially identically until the internal combustion engine is switched back on.

Provided are a driving force control method and device for a hybrid vehicle, each capable of effectively absorbing torque fluctuation of an engine while suppressing deterioration in energy efficiency. The driving force control device for a hybrid vehicle comprises a PCM configured to: identify a speed reduction ratio in a driving force transmission mechanism; estimate an average torque output by an engine; estimate a torque fluctuation component of the torque output by the engine; set a countertorque for suppressing the estimated torque fluctuation component; and control an electric motor to output the set countertorque, wherein the PCM is operable, under a condition that the average torque output by the engine and an engine speed are constant, to set the countertorque such that, as the speed reduction ratio becomes smaller, the absolute value of the countertorque becomes larger.

A method for controlling an electric device including: a step of comparing the rotation speed of an internal combustion engine at the time when it has been determined that the internal combustion engine is to transition to a rotation stop state with a specified threshold; and a step of performing rotation-speed increasing control, in a case where the rotation speed of the internal combustion engine at the time of the determination is higher than the threshold, in which in a case where the rotation speed of the internal combustion engine at the time of the determination is not higher than the threshold, the rotation speed of the internal combustion engine is not made higher than the rotation speed at the time of the determination but is let to decrease to stop the internal combustion engine.

A vehicle control device controls a vehicle including an internal combustion engine, an electric motor, a drive wheel, and a lock-up clutch provided in a power transmission path from the internal combustion engine and the electric motor to the drive wheel. The vehicle control device is configured to: not execute a motor vibration damping control and a slip vibration damping control in a non-vibration damping region; execute the motor vibration damping control and the slip vibration damping control in a first vibration damping region in a high load state or a low rotation speed state; and execute the motor vibration damping control and not execute the slip vibration damping control in a second vibration damping region in a medium load state or a medium rotation speed state.

A engine starting method is carried out to start an engine of a vehicle. The vehicle includes a first hub, a second hub, and a damper. The damper connects the first hub and the second hub in a power transmission path between the engine and a generator capable of power generation and powered travel. The engine starting method determines whether or not the engine needs to be started, begins to crank the engine via the generator when the engine needs to be started, performs a first ignition when torque fluctuation caused by torsion in the first hub and the second hub is in a range of being absorbable by the damper during the cranking, and suppresses engine torque generated by the first ignition below engine torque generated by second and subsequent ignitions.

Provided are a driving force control method and device for a hybrid vehicle, each capable of effectively absorbing torque fluctuation of an engine while suppressing deterioration in energy efficiency. The driving force control device for a hybrid vehicle comprises a PCM configured to: estimate an average torque output by an engine; estimate a torque fluctuation component of the torque output by the engine; set a countertorque for suppressing the estimated torque fluctuation component; and control an electric motor to output the set countertorque, wherein the PCM is operable, under a condition that the average torque output by the engine is constant, to set the countertorque such that, as an engine speed of the engine becomes larger, the absolute value of the countertorque becomes larger.

In an electric device control method and an electric device of the present invention, during a period in which a rotational speed of an internal combustion engine shifting from a non-combustion mode to a combustion mode is decreased to a rotational speed within a predetermined rotational-speed range by a first electric motor connected to the internal combustion engine, a torque generated by the internal combustion engine is set lower than a required torque within the predetermined rotational-speed range for the internal combustion engine in the combustion mode.