摘要:
A system and method for controlling an operation of an internal combustion engine of a vehicle having an automatic transmission in which at least one of predetermined fuel supply recovery engine revolution speed or predetermined fuel supply cut-off engine revolution speed is varied during the engine deceleration condition according to a state of operation of the automatic transmission. In the first preferred embodiment, a downshift operation of the automatic transmission is detected. In the second preferred embodiment, an overrun clutch solenoid is turned on (energized). In the latter case, both fuel supply recovery and fuel supply cut-off engine revolution speeds are set to higher values than those when the clutch solenoid is turned off (deenergized).
摘要:
In order to determine a malfunction which results in the loss of torque reduction control, the engine speed and the torque converter characteristics are monitored when a torque down signal is issued. The maximum engine torque which should be produced under such circumstances is used to derive a corresponding maximum engine speed value. If the actual engine speed exceeds the estimated value, appropriate torque down control can be assumed to have been lost. In response a fail safe such as boosting line pressure to switching to an alternative source of torque control can implemented. A suitable warning signal can also be generated.
摘要:
A hydraulic pressure, i.e., a line pressure, of a hydraulic fluid supplied from an engine driven pump toward a hydraulically actuable coupling of an automatic transmission is held at the maximum pressure value when a temperature of an automatic transmission oil is less than a predetermined temperature value. However, the hydraulic pressure is temporarily decreased from the maximum pressure value to the minimum pressure value for a period of time after cranking of the engine when the transmission oil temperature is lower than the predetermined temperature value. Owing to a decreased load on the engine by the oil pump, smooth cranking and subsequent warming-up operation of the engine is assured under cold whether condition when the automatic transmission oil temperature is lower than the predetermined temperature value.
摘要:
A predetermined control on an engine, i.e., a fuel-cut operation, is executed after an accelerator has been released under predetermined conditions when vehicle speed is higher than a fuel-cut vehicle speed value and engine speed is higher than or equal to a fuel-cut engine speed value. In an automatic transmission drivingly connected to the engine via a torque converter, a gear shift is initiated after the accelerator has been released. During a shift of the same kind, there occurs a variability in shift shock between the cases with and without the execution of the fuel-cut operation. In order to reduce this variability, the execution of the fuel-cut operation is inhibited until completion of the shift after the accelerator has been released under the predetermined conditions.
摘要:
A unified control device for engine and automatic transmission of an automotive vehicles serves to alleviate a racing select shock which occurs upon engagement of a driving clutch in the transmission when selecting a running range of the transmission to start the vehicle with an accelerator pedal depressed. The control device achieves a reduction control during changeover of the transmission into a running range from a racing state, to reduce at least one parameter representing the output power to be transmitted from the engine to driving wheels via the transmission, such as engine speed, engine output and/or transfer torque capacity of the clutch, etc. The reduction control is stopped as soon as the completion of engagement of the driving clutch has been detected, to allow the vehicle to be started without engine stalling.
摘要:
In control apparatus and method for an automotive vehicle, the vehicle having a continuously variable transmission associated with a vehicular engine and including a belt that transmits a revolution of a primary pulley to a secondary pulley that is enabled to make a gear shift by modifying a pulley ratio between the primary and secondary pulleys with a hydraulic, a determination is made as to whether a belt slip between at least one of the primary and the secondary pulleys occurs and an output section outputs a signal to command an engine control unit to increase an engine speed by a predetermined engine speed when the belt slip is determined to occur.
摘要:
A speed change ratio control unit for a continuously variable transmission that uses a step motor as a driving actuator of a speed change control valve that compares a variable ASTP representing a step position of the step motor and a step position BSTP of the step motor that is necessary for realizing a desired speed change ratio at every predetermined operation cycle, and if ASTP≠BSTP is satisfied determines that a step-out has occurred on the step motor.
摘要:
During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.
摘要:
A downshift control in an automatic transmission is disclosed wherein magnitude of servo activating hydraulic fluid pressure is temporarily decreased as a function of vehicle speed when the automatic transmission effects a downshift from a current gear ratio to a new gear ratio. Owing to this arrangement, a fluid operated frictional device associated with the current gear ratio is released quickly without any lag to allow quick increase in engine speed during the downshift with the throttle fully opened at a high vehicle speed, i.e., a power-on downshift at high vehicle speed.
摘要:
A hydraulic-pressure control system for a four-wheel drive vehicle with a hydraulic-pressure operated transfer clutch, which is responsive to a controlled clutch pressure applied thereto to distribute a driving torque passing from a transmission between main drive wheels and auxiliary drive wheels, comprises a pilot-operated directional control valve connected to the transfer clutch for cutting off a supply of hydraulic fluid of the controlled clutch pressure to the transfer clutch and for directing hydraulic fluid of the controlled clutch pressure to the transfer clutch. The system includes a clutch pressure control valve provided upstream of the directional control valve, which pressure control valve is responsive to an external pilot pressure for producing the controlled clutch pressure, and a duty-ratio controlled solenoid valve for decreasingly adjusting the external pilot pressure to be output to the pressure-reduction valve in accordance with an increase in a duty ratio. A controller is provided for forcibly outputting a duty-cycle controlled exciting current of a predetermined high duty ratio such as 100% to the duty-ratio controlled solenoid valve to reduce the controlled clutch pressure to a low pressure level (preferably a minimum clutch pressure) when the directional control valve is maintained at the cut-off position in case of 4L range wherein the transmission is loaded heavier.