Abstract: A method/system for controlling downshifting in an automated mechanical transmission system (10) utilized on a vehicle having a manually controlled engine brake (46) and foot brake (44) system. The engine speed at which downshifts are commanded (ESD/S) is modified as a function of sensed operation of the engine brake (EB?) and foot brake (FB) systems.

Abstract: A motor vehicle includes an internal combustion engine and an automatic transmission powered by the engine. The engine has a throttle valve for controlling the amount of air fed thereto. The transmission selectively assumes an Over-drive possible D-range wherein both a lock-up ON condition and a lock-up OFF condition are available and an Over-drive impossible D-range wherein only the lock-up OFF condition is kept. A control system comprises a first section for detecting a first condition of the engine wherein an open degree of the throttle valve is reduced to a certain degree; a second section for detecting a second condition of the transmission wherein the lock-up ON condition of the Over-drive possible D-range is kept; and a third section for engaging a friction element of the transmission to induce an engine brake when the first and second sections detect the first and second conditions respectively.

Abstract: An automatic transmission control apparatus for a vehicle and a control method thereof keep the optimum vehicle speed even on a road with a gradient such as an up hill or an down hill in line. Whether or not it is necessary to change the gear ratio is determined based on a vehicle speed and the road gradient and for generating a command signal to change the gear ratio if necessary, thereby changing the gear ratio.

Abstract: A vehicle speed control system comprises a section for calculating a command driving force-required to make a sensed vehicle speed equal to a preset command vehicle speed, a section for calculating a command engine output in accordance with the command driving force and the command vehicle speed, a section for calculating a command engine speed corresponding to the command engine output from a predetermined engine torque-versus-speed characteristic relationship in an engine constraint state of minimum throttle setting and fuel cutoff inhibition when the command driving. force is negative, and a section for calculating a command transmission ratio in accordance with the command engine speed. When the driving force command is negative, the control system put the engine in the constraint state and controls a continuously variable transmission in response to the command transmission ratio so as to prevent undesired vehicle speed hunting.

Abstract: A combined engine and transmission control unit for a motor vehicle uses the position of the accelerator pedal to calculate setpoint values for the engine and the transmission of the motor vehicle. The control unit has a drive-train controller, which, when the engine is not in traction mode, controls the driving mode of the motor vehicle. The driving mode is adapted to the surroundings of the motor vehicle and the driving style of the driver. The drive-train controller activates an engine torque control when brake slip is detected, and the transmission controller prescribes a lower gear than is provided for the unbraked mode of the motor vehicle by a characteristic diagram.

Abstract: A control system and method for an automated mechanical transmission system (10) including an engine braking mechanism (14A) is provided for allowing operator request for an automatic direct downshift into the selected ratio (GR.sub.EB) automatically determined to provide optimum engine braking under current vehicle operating conditions. Retaining the control lever (1) in a displaced position for longer than a reference period of time (REF), such as one or two seconds, while the engine brake is active, will initiate the automatic determination and shift into the selected ratio (GR.sub.EB) determined to provide optimum engine braking under current vehicle operating conditions procedure.

Abstract: In a vehicular automatic transmission, a coast downshift is executed in an appropriate engine-braking state and with a light gearshift shock. While predetermined conditions for the execution of the downshift are met, an oil pressure to be fed to a clutch (c12 in FIG. 1) on the side of a gearshift output stage (a lower speed stage) is controlled, for example, in order that the input shaft speed (turbine speed01 in FIG. 1) of the automatic transmission may agree with a desired value adapted to keep the weak engine-braking state.

Abstract: According to a torque converter lockup control, a lockup actuator, including a lockup solenoid, is operative responsive to an output command signal issued by a controller to adjust lockup clutch engagement force to a commanded value. The lockup clutch engagement force is a force with which the lockup clutch is engaged. The controller determines the commanded value as a function of a deviation between a current value of slip speed within the torque converter and a desired value thereof. For preventing the lockup clutch from shifting deeply into its converter position when the deviation persists to stay in the neighborhood of zero, the controller sets a limit to the determined commanded value during operation of the lockup clutch in the slip lockup mode.

Abstract: In a vehicle comprising a continuously variable transmission, an engine braking force is increased or decreased via speed ratio control. First, a first target speed ratio is determined based on a vehicle speed. Information relating to vehicle running conditions is acquired, and the first target speed ratio is modified to a second target speed ratio according to this information by controlling the speed ratio of the continuously variable transmission to the second target speed ratio. Hence, the optimum engine braking force is obtained according to the running conditions.

Abstract: An engine and generator/motor are connected to the input shaft of a continuously variable transmission, and the output shaft of the continuously variable transmission is connected to drive wheels. A target value of a coasting torque acting on the output shaft during coasting is set according to a vehicle speed. A real coasting torque is estimated from the output torque of the engine and frictional torque of the continuously variable transmission. By making the generator/motor function as a generator or a motor, fluctuation of the engine braking force due to a variation of drive ratio during coasting is suppressed so that the real coasting torque coincides with the target value.

Abstract: A hydraulic control unit of an automatic transmission calculates deceleration during a coasting downshift, and calculates a piston play offsetting time, that is, the lag time that elapses between a shift decision and the start of the shift, on the basis of a correction value determined in accordance with the lag time learned from the previous shift. Based on the rate of deceleration and the piston play offsetting time, the downshift line in the speed shift map is corrected, that is, advanced in timing. Using this timing-advanced shift line, the control unit makes an earlier shift decision such that the shift starts in a proper state of operation, thus reducing shift shock during a coasting downshift and preventing excessive engine speed during a high-speed upshift.

Abstract: In a driven state, a hydraulic pressure of disengagement side is set at a stroke pressure, a one-way clutch in an operating state is over-run, an engine rotation speed is in an idle state, and an automatic transmission is in a neutral state. In a drive state, the hydraulic pressure of disengagement side is controlled so that a difference between an engine rotation speed and an input rotation speed reaches a difference between the both rotation speeds at a start of the shift control. In a state of a synchronized rotation after the shift, the hydraulic pressure of disengagement side is controlled so that the input rotation reaches the synchronized rotation.

Abstract: A system for managing engine retarding torque during coast mode operation includes a control computer operable in one embodiment to control boost pressure, engine compression brake setting and/or engine accessory deactivation upon detection of coast mode operation with the engine compression brakes enabled. In another embodiment, the control computer is operable to determine a current engine retarding torque value, based either on an estimation thereof as a function of current boost pressure and engine compression brake setting or based on a mass estimation technique accounting for the grade of the road, and control boost pressure, engine compression brake operation and/or engine accessory deactivation to thereby control engine retarding torque upon detection of coast mode operation with the engine brakes enabled.

Abstract: A system for adjusting the gear ratio of a transmission is continuously adjusted with respect to its gear ratio and mounted downstream of the vehicle motor. Furthermore, downhill travel is detected and the adjustment of the gear ratio of the transmission is made in dependence upon the detected downhill travel. The system is are provided for adjusting the gear ratio in reaction to the detected downhill travel in such a manner that the transmission input rpm and/or the engine rpm increases in a pregiven manner. The advantage of the system is that the transition from normal operation (no downhill travel) to the downhill travel function of the system takes place at first unnoticeable for the driver because the engine rpm increases in a manner not unexpected for the driver.

Abstract: A control for a vehicle fitted with an internal combustion engine as a power source. At the time of a driver deceleration intention (when travelling downhill), then with an arrangement where the opening control for the throttle valve and the fuel supply control (fuel cut off control or the like) are automatically controlled in order to obtain a predetermined target vehicle acceleration, when the intention of the driver shifts from a deceleration intention to a non deceleration intention, and hence the automatic control reverts to normal control, the fuel supply control is returned to normal control once the throttle valve opening has reached a predetermined opening. In this way, it is possible to avoid the situation where for example, the fuel supply control reverts to normal control with the throttle valve opened more than necessary. Consequently the occurrence of shock or an unintended acceleration due to a mismatch in the throttle opening at the time of reverting to normal control can be suppressed.

Abstract: Uncomfortable travel of a vehicle due to engine brake actions during the travel of the vehicle in traffic is prevented without using an one-way clutch within a transmission mechanism. An automatic transmission is composed of rotational elements that are braked at the time of establishing low stages, a brake that brakes the rotational elements, and control systems which control the oil pressure of the hydraulic servo in the brake. A band brake that creates differences in application forces, using self-energizing and deenergizing actions, serves as the brake, which is set to have an area in which the oil pressure during the drive is lower than the oil pressure during the non-drive, by setting the self-energizing direction as a direction of rotation of the rotational element during the drive and the deenergizing direction as an opposite direction of rotation of the rotational element during the non-drive.

Abstract: An automatic transmission control system, which applies an ordinary gear shift control map set up for flat road driving and a downgrade gear shift set up for downgrade driving which has broadened range of driving conditions for lower gears, causes gear shifts according to the ordinary gear shift control map even during downward driving when an accelerator pedal is stepped on with intention of accelerating the vehicle.

Abstract: Apparatus for controlling an engine-braking force to be applied to a motor vehicle, including (a) a throttle valve drive device for operating a throttle valve to change an amount of opening of the throttle valve, (b) a throttle opening control device which is operated upon a manual shift-down action of the automatic transmission as a result of operation of an operator's controlled member, for increasing the amount of opening of the throttle valve to temporarily increase an engine speed to a level which is expected to be established after the manual shift-down action, so as to assure smooth application of engine braking to the motor vehicle, and (c) a throttle opening control enabling/disabling device for inhibiting an operation of the throttle opening control means when a predetermined condition is satisfied after completion of the manual shift-down action of the automatic transmission, and permitting the operation of the throttle opening control means when the predetermined condition is not satisfied.

Abstract: A lock-up control apparatus for a vehicle automatic transmission enables an engine stalling prevention at the time of a sudden deceleration in the lock-up state of a torque converter without causing the slip of the torque converter before the sudden deceleration, and prevents effectiveness of the fuel consumption from being sacrificed by a fuel cut. A controller performs the change-speed control on an automatic transmission through shift solenoids and on the basis of a throttle opening and a transmission output speed, and also performs the lock-up control of the torque converter through a lock-up solenoid. During the coasting drive when the throttle opening is set close to zero, the controller sets the torque converter to have a minimum lock-up capacity through the lock-up solenoid within such a range that no slip occurs.

Abstract: A shift control method for an automatic transmission of a vehicle allows a kick down piston of a kick down brake in the automatic transmission to fully return after a 4-3 speed downshift operation before performing a 3-2 speed downshift operation. If it is determined that a 4-3 speed downshift signal was output by the transmission control unit, the transmission control unit is monitored to determine if a 3-2 speed downshift signal is output. A 3-2 speed downshift operation in response to a detect 3-2 speed downshift signal will then be prohibited for a predetermined period of time for the kick down piston of the kick down brake in the automatic transmission to fully return after the 4-3 speed downshift operation. Next, the 3-2 speed downshift operation will be performed in response to the 3-2 downshift signal after the predetermined period of time.

Abstract: A control section for controlling a gearshift position changeover mechanism of an automatic transmission includes a downshift determination section for determining whether or not a downshift on descending roads is required, and a downshift command section for outputting a downshift command signal when it is determined that downshift is necessary. The downshift determination section is provided with a learning correction section for effecting a learning correction of a determination reference based on a manipulation characteristic of a driver immediately after completion of downshift each time a downshift takes place.

Abstract: A speed change control method controls changeover between gearshift positions of an automotive automatic transmission using a detected running condition parameter and a detected degree of necessity of engine braking. The degree of necessity of engine braking is detected using a neural network receiving the detected parameter as an input. Then, a shift pattern is preferably selected by fuzzy inference based on the detected parameter and degree of necessity of engine braking.

Abstract: A vehicular automatic transmission and control system therefor includes an automatic transmission including a planetary gear unit and a plurality of friction elements for connecting the components of the planetary gear unit selectively to rotary members or stationary members; a hydraulic control unit for selectively switching and controlling oil pressures to be fed to the friction elements; and an electronic control unit for outputting a signal indicating the running state of a vehicle to control the feed of the oil pressures to the friction elements.

Abstract: A control system/method for an at least partially automated mechanical transmission system (10), inclading a controller (106) operated engine brake (EB), is provided. The control system/method is effective to determine if selected upshifts into a target gear ratio are feasible (212, 214) or not feasible (216) under current vehicle operating conditions and to prohibit the initiation of not feasible selected upshifts. The transmission system includes an engine brake actuator (23A) operable by the system controller (106). selected upshifts are evaluated and will be implemented, if feasible, in a sequence wherein feasibility is a function of engine deceleration (dES/dt), and engine deceleration is assigned expected values at minimum to progressively greater engine braking.

Abstract: A shift control apparatus for an automatic transmission of a motor vehicle is disclosed. The shift control apparatus includes a shift control device for automatically shifting the transmission according to a predetermined shift control pattern, on the basis of a speed of the engine and a currently required output of the engine. When a vehicle driver operates to re-accelerate the vehicle after deceleration with the transmission shifted down to the low-speed gear position, the transmission is shifted up from the lower-speed gear position to the high-speed gear position having the smaller speed reduction ratio than the lower-speed gear position, if a predetermined period of time has not elapsed after the low-speed gear position is established.

Abstract: A method of automatically changing the speed of a self-propelled motor vehicle while supplying an adequate amount of cooling oil to a retarder during retarder operation, avoids unnecessary shifting even under conditions wherein an accelerator is released. The method of automatic speed change is so adapted as to move the shift points at each stage of speed to a higher vehicle-speed side as compared with normal driving.