Systems and methods for operating a hybrid vehicle are described. In one example, a torque reserve for starting an engine via an electric machine is adjusted responsive to vehicle operating conditions. The torque reserve may set aside a portion of torque that an electric machine may produce for cranking and starting an engine.

A hybrid power transmission mechanism includes an engine; a motor/generator having a rotor and a stator; a driven machine; a planetary gear mechanism having a sun gear, an internal gear drivingly connected to the rotor, a planetary gear, and a planetary carrier shaft including first and second extension shaft parts extending from the planetary gear in opposite directions; a first clutch switchable between a state of allowing transmission of power between the first shaft and the internal gear and a state of not allowing transmission of power therebetween; and a second clutch switchable between a state of allowing rotation of the sun gear and a state of not allowing rotation thereof. A first shaft that outputs power of the engine and a second shaft that inputs power to the driven machine are drivingly connected to the first and second extension shaft parts of the planetary carrier shaft, respectively.

A hybrid power transmission mechanism includes an engine; a motor/generator having a rotor and a stator; a driven machine; a planetary gear mechanism having a sun gear, an internal gear drivingly connected to the rotor, a planetary gear, and a planetary carrier shaft including first and second extension shaft parts extending from the planetary gear in opposite directions; a first clutch switchable between a state of allowing transmission of power between the first shaft and the internal gear and a state of not allowing transmission of power therebetween; and a second clutch switchable between a state of allowing rotation of the sun gear and a state of not allowing rotation thereof. A first shaft that outputs power of the engine and a second shaft that inputs power to the driven machine are drivingly connected to the first and second extension shaft parts of the planetary carrier shaft, respectively.

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.

A ram air turbine (RAT) system can include a generator configured to be turned by a RAT and to output an alternating current (AC) power, a generator control unit (GCU) configured to control an output of the generator, a rectifying module configured to rectify the AC power into a direct current (DC) power, and a DC load configured to receive the DC power from the rectifying module. The DC load can be operatively connected to the GCU to provide feedback from the DC load to the GCU. The GCU can be configured to control the output of the generator as a function of the feedback to prevent stalling of the RAT and/or doorbelling current and/or voltage in the system caused by disconnecting the generator from the DC load.

Systems and methods for operating an engine that may be selectively automatically stopped and started are described. In one example, the method adjusts an amount of time that the engine may be inhibited from automatically stopping based on driver inputs such as driver demand pedal position, vehicle speed, and braking torque.

A hybrid power transmission mechanism includes an engine; a motor/generator having a rotor and a stator; a driven machine; a planetary gear mechanism having a sun gear, an internal gear drivingly connected to the rotor, a planetary gear, and a planetary carrier shaft including first and second extension shaft parts extending from the planetary gear in opposite directions; a first clutch switchable between a state of allowing transmission of power between the first shaft and the internal gear and a state of not allowing transmission of power therebetween; and a second clutch switchable between a state of allowing rotation of the sun gear and a state of not allowing rotation thereof. A first shaft that outputs power of the engine and a second shaft that inputs power to the driven machine are drivingly connected to the first and second extension shaft parts of the planetary carrier shaft, respectively.

A hybrid power transmission mechanism includes an engine; a motor/generator having a rotor and a stator; a driven machine; a planetary gear mechanism having a sun gear, an internal gear drivingly connected to the rotor, a planetary gear, and a planetary carrier shaft including first and second extension shaft parts extending from the planetary gear in opposite directions; a first clutch switchable between a state of allowing transmission of power between the first shaft and the internal gear and a state of not allowing transmission of power therebetween; and a second clutch switchable between a state of allowing rotation of the sun gear and a state of not allowing rotation thereof. A first shaft that outputs power of the engine and a second shaft that inputs power to the driven machine are drivingly connected to the first and second extension shaft parts of the planetary carrier shaft, respectively.

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.