A method for operating a vehicle that includes a driveline disconnect clutch is described. In one example, the method adjusts torque of an electric machine in response to a estimated torque capacity of the driveline disconnect clutch. The estimated torque capacity of the driveline disconnect clutch is based on a combined inertia of a dual mass flywheel and the driveline disconnect clutch.

Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method selects one or more electric machines to start an engine. The method may reference a data structure, such as a matrix or table, and the matrix or table outputs which of the one or more electric machines is applied to start the engine.

Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method selects one or more electric machines to start an engine. The method may reference a data structure, such as a matrix or table, and the matrix or table outputs which of the one or more electric machines is applied to start the engine.

Upon a request for switching from a first travel mode of traveling with a clutch disengaged and operation of an engine stopped to a second travel mode of traveling with the clutch engaged and the engine operating, a controller for a hybrid vehicle restarts the engine in the following manner. That is, the controller restarts the engine in a first start mode of starting combustion in the engine with the clutch non-fully engaged when a rotation speed of a motor is greater than a determination value and restarts the engine in a second start mode of starting combustion in the engine with the clutch fully engaged when the rotation speed of the motor is less than or equal to the determination value.

A control device for a hybrid vehicle includes a push-start mode and a motor start mode. The push-start mode transmits a driving force from driving wheels to the engine via a first transmission route at a speed detected by a speed detection means equal to or more than a predetermined speed to start the engine. The motor start mode starts the engine using a driving force of the motor at a speed equal to or less than the predetermined speed as well as in a stopped state. At a speed outside a speed range that either mode is executable when a start command of the engine occurs in driving only using the electric motor as the driving source, a control means performs the driving force reduction control for reducing a driving force transmitted from the electric motor to the driving wheels of the vehicle.

A control device for a hybrid vehicle includes a push-start mode and a motor start mode. The push-start mode transmits a driving force from driving wheels to the engine via a first transmission route at a speed detected by a speed detection means equal to or more than a predetermined speed to start the engine. The motor start mode starts the engine using a driving force of the motor at a speed equal to or less than the predetermined speed as well as in a stopped state. At a speed outside a speed range that either mode is executable when a start command of the engine occurs in driving only using the electric motor as the driving source, a control means performs the driving force reduction control for reducing a driving force transmitted from the electric motor to the driving wheels of the vehicle.

An internal combustion engine of a motor vehicle includes an output shaft and a spring element which can rotate with the output shaft which is to be tensioned as a result of a deactivation of the internal combustion engine by a rotation of the output shaft, where a spring force can be provided by the spring element and where by the spring force the output shaft can be set into rotation in the event of a start following the deactivation. Via a locking device the output shaft is to be secured against a rotation after tensioning the spring element and while the spring element is tensioned. A blocking device can be shifted between a blocking state securing a first part of the spring element, which has a second part non-rotationally connected to the output shaft, against a rotation and a release state releasing the first part for a rotation.

An internal combustion engine of a motor vehicle includes an output shaft and a spring element which can rotate with the output shaft which is to be tensioned as a result of a deactivation of the internal combustion engine by a rotation of the output shaft, where a spring force can be provided by the spring element and where by the spring force the output shaft can be set into rotation in the event of a start following the deactivation. Via a locking device the output shaft is to be secured against a rotation after tensioning the spring element and while the spring element is tensioned. A blocking device can be shifted between a blocking state securing a first part of the spring element, which has a second part non-rotationally connected to the output shaft, against a rotation and a release state releasing the first part for a rotation.

A vehicle includes a starter motor, an engine having an output mechanically coupled to the starter motor, a transmission having an input, and an electric machine mechanically coupled to the transmission input. The vehicle further includes a clutch configured to mechanically couple the electric machine and the output of the engine, and at least one controller. The at least one controller is programmed to initiate an engine start based on driver demand. The controller is further configured to enable pressure to the clutch for the engine start if driver demand is less than a calibratable torque value or enable the starter motor for the engine start if the driver demand is greater than a calibratable torque value. The controller may lock the clutch to the output of the engine in response to the speed of the engine being approximately equal to the speed of the electric machine.

An engine starting control system for hybrid vehicles is provided to prevent a temporal drop in drive force when starting an engine. The control system maintains an operating mode of a switching mechanism when starting the engine by the first motor, in a case that the vehicle is propelled in the forward direction by the first motor and that the switching mechanism is in a second mode, or in a case that the vehicle is propelled in the reverse direction by the first motor and that the switching mechanism is in the first mode. Thereafter, the control system increases a rotational speed of the engine to a self-sustaining speed, switches the operating mode of the switching mechanism, and increases torque of the engine.