Methods and systems are provided for cycle-to-cycle torque reductions under exhaust component temperature constraints. In one example, a method may include, responsive to a torque reduction request, introducing a lambda split between two sets of cylinders over a plurality of engine cycles while maintaining an average of stoichiometry between the two sets of cylinders, and, responsive to reaching a lambda split threshold, introducing differentially delayed ignition timing in both sets of cylinders. In this way, fast torque reduction may be provided while maintaining a globally stoichiometric air-fuel ratio, thereby decreasing vehicle emissions, and reducing heat-related degradation to exhaust components.

A method for operating a drive device of a motor vehicle, having an internal combustion engine and at least one switchable mechanism. The mechanism can be switched to change an operating state influencing a fuel consumption and switching causes an increased fuel consumption. It is proposed that a torque and a rotational speed of the internal combustion engine are predicted depending on a current operating situation, that a dwell time of the mechanism in a switching state is predicted depending on the torque and the rotational speed, and that the mechanism for changing the operating state is actuated depending on the dwell time.

A work vehicle includes an engine mounted on a traveling body including traveling wheels; a hydraulic stepless transmission that shifts a speed of the driving force from the engine; a gear shift pedal that performs an acceleration/deceleration operation of a shifted output from the hydraulic stepless transmission; and a control section that controls the engine and the hydraulic stepless transmission based on the operation amount of the gear shift pedal. When an operation on a set switch is received in a state where the gear shift pedal is pressed by a foot operation in an auto-cruise standby mode, the control section stores the vehicle speed and the number of engine revolutions in accordance with the foot operation position of the gear shift pedal and shifts to an auto-cruise mode.

A gear shift control device for a continuously variable transmission of a vehicle is configured to steplessly and continuously change and output a rotation speed of an engine. The gear shift control device includes a gear shift control unit and a torque control command unit. The gear shift control unit is configured to implement a pseudo-stepped upshift control to change a gear shift ratio in steps when upshifting the continuously variable transmission. The torque control command unit is configured to output a torque reduction command so as to reduce an engine torque in conjunction with the pseudo-stepped upshift control so that reduction of the engine torque starts before a point in time when an actual gear shift ratio starts changing in response to an upshift command.

Methods and systems are provided for controlling an engine speed in a hybrid vehicle system during steady-state conditions and in response to transient acceleration and/or deceleration requests. In one example, an engine speed is controlled to an optimal engine speed for fuel economy during steady-state conditions, and in response to an acceleration or deceleration request, a target engine speed is obtained from a rate-limited optimal engine speed to vehicle speed ratio, and the engine is controlled to the target engine speed provided the target speed is below a threshold difference from optimal engine speed. In this way, the vehicle system may simulate a fixed ratio transmission during accelerations and decelerations, while maintaining optimal engine speed for fuel economy at steady state.

Provided is a method for changing gear ratio in a gearbox comprising: receiving a signal to change the gear ratio; calculating braking torque that the engine should provide to reduce the rotational speed of the engine to a target rotational speed; phase-shifting a second camshaft in relation to the crankshaft, to a state where the exhaust valve is controlled to be opened during the expansion stroke and closed during the exhaust stroke; disconnecting the engine from the driving wheel; opening and closing the exhaust valve with a decompression device in a transition area between an exhaust stroke and an inlet stroke and also between a compression stroke and an expansion stroke, when the piston is at a top dead center in the cylinder to achieve engine braking through compression in the cylinders during the exhaust stroke and the compression stroke, and f) shifting a gear in the gearbox.

A vehicle with an automatic downshift function, comprises an engine including a throttle device and an ignition device; an engine speed sensor which detects an engine speed; a shift operation member which is operated by a rider; a manual transmission connected to the engine, a shift operation sensor which detects the operation of the shift operation member; and a controller which controls the engine based on a detection signal of the engine speed sensor and a detection signal of the shift operation sensor. In a case where the controller determines that a deceleration shift operation has been initiated based on the detection signal of the shift operation sensor, the controller performs an automatic downshift control so that the controller controls the throttle device to increase an intake-air amount and controls the ignition device to change an ignition timing, based on the engine speed detected by the engine speed sensor.

A system and method are disclosed for controlling shifting of a vehicle having an automated manual transmission. In the system and method, an amount of fuel being provided to a first grouping of cylinders is reduced, where the first grouping of cylinders are fewer than all of the available cylinders; the first grouping of cylinders are placed in an engine braking mode; a first gear of the vehicle transmission is disengaged; an amount of fuel being provided to a second grouping of cylinders which does not include the first grouping of cylinders is reduced; engine speed is reduced by braking; and a second gear of the transmission is engaged.

A mechanical supercharging system includes a stepped transmission that connects a crankshaft of an internal combustion engine with driving wheels, a centrifugal supercharger including a rotary drive shaft connected to the crankshaft, a variable speed ratio device that changes a speed ratio of the rotary drive shaft to the crankshaft, the variable speed ratio device being provided between the crankshaft and the rotary drive shaft; and a control device configured to control the speed ratio. The control device increases the speed ratio during the upshift operation more than the speed ratio before start of the upshift operation.

A control device for a multi-stage automatic transmission-equipped vehicle includes a hydraulic power controller, a combustion controller configured to, if a predetermined combustion stop condition is satisfied when the vehicle is traveling, perform deceleration-period combustion stop control, and limit combustion restart triggered by a reduction in rotational speed of an internal combustion engine, during execution of the deceleration-period combustion stop control, and a motoring controller configured to control the rotational drive of the internal combustion engine by a motor during execution of the deceleration-period combustion stop control so that the rotational speed of the internal combustion engine is maintained at a predetermined rotational speed during a period of time from the time that the rotational speed of the internal combustion engine decreases to the predetermined rotational speed until downshifting to a predetermined gear ratio is completed.