114 results about "Downshifting" patented technology

A control system for an automatic vehicle transmission which has auto-shifting means or auto-shift mode for determining a gear to be shifted to in accordance with predetermined gearshift scheduling characteristics in response to the detected vehicle speed and the engine load, and manual-shifting means or manual-shift mode for determining a gear to be shifted to in response to a manual-shift command generated by the vehicle driver. The system further includes auto-downshifting means or sub-auto-shift mode for determining a gear to be downshifted to if the detected vehicle speed is less than a threshold value when the manual-shifting means is in operation. In the system it is estimated whether the vehicle is hill climbing or hill descending, and the threshold value is increasing when the vehicle is hill climbing or descending. With the arrangement, it becomes possible to downshift before the drivability or driver's comfort is degraded during the hill climbing or descending.

A method of double-downshifting from a first gear ratio to a second gear ratio includes the steps of first reducing torque transfer from a first clutch to a first driven gear. Engine speed then increases. Next, torque transfer from a second clutch to a third driven gear is increased while simultaneously the first clutch is disengaged from the first driven gear. Torque transfer from the second clutch to the third driven gear is then reduced. Torque transfer from the second clutch to the third driven gear is next increased. The first clutch is engaged to the second driven gear. Then, torque transfer from the first clutch to the second driven gear is increased while simultaneously the torque transfer from the second clutch to the third driven gear is reduced. Finally, the second clutch is disengaged from the third driven gear.

A driving control apparatus for a vehicle which includes an engine which generates power by fuel combustion; a transmission which changes engagement / disengagement states of plural frictional engagement devices so as to realize plural shift speeds whose gear ratios are different from each other; a fuel cut device which stops fuel supply to the engine when a predetermined fuel cut condition including a condition that the vehicle is coasting with a throttle valve of the engine being fully closed is satisfied; a coasting time disengagement restricting device which maintains a high speed side frictional engagement device in an engagement state until a low speed side frictional engagement device obtains a predetermined torque capacity at the time of automatic downshifting of the transmission during coasting; and a disengagement restriction stop device which stops control by the coasting time engagement restricting device so as to reduce a torque capacity of the high speed side frictional engagement device, when control by the fuel cut device is cancelled and fuel supply is restarted in the case where downshifting of the transmission is output while fuel supply is stopped by the fuel cut device and the high speed side frictional engagement device is maintained in the engagement state by the coasting time disengagement restricting device.

A shift control method for a vehicle with a Dual Clutch Transmission (DCT) includes comparing, by a controller, a current clutch temperature with a first predetermined reference value and a second predetermined reference value, the second predetermined reference value being greater than the first reference value, preventing, by the controller, coaxial power-on downshifting when the clutch temperature is greater than the first reference value, and reducing, by the controller, a shift time by preventing coaxial power-on downshifting when the clutch temperature is greater than the second reference value and then increasing a shift speed when biaxial full skip shifting is required.

A transmission control system, includes: 1) a high speed side friction element for establishing a high speed side change gear; and 2) a low speed side friction element for establishing a low speed side change gear. After a disengagement of the high speed side friction element, the low speed side friction element makes an engagement for carrying out a downshift from the high speed side change gear to the low speed side change gear. When the downshift is carried out with an accelerator turned off, a stepping on the accelerator sensed in a period between the following times: i) a time for commanding a start of a transmission, and ii) a time for the low speed side friction element to start a conveyance of a torque, prevents a changeover to the low speed side change gear, thus keeping the high speed side change gear.

A hybrid vehicle is equipped with an engine that is connected to a power split mechanism, a generator, an electric motor, and also a stepped transmission that is arranged between the electric motor and a drive shaft. An electronic control unit (an ECU) with which this hybrid vehicle is equipped revises a down line downward to make a downshift likely to occur when at least one of a prescribed generator condition and a prescribed electric motor condition is fulfilled. The generator condition includes that the temperature of the generator is equal to or higher than a first reference temperature and that an absolute value of a rotational speed of the generator decreases due to the making of the downshift. The electric motor condition includes that the temperature of the electric motor is equal to or higher than a third reference temperature.

A method for controlling a cruise control operable to maintain a set speed of a vehicle according to a plurality of goal droop curves is provided. The goal droop curves include: an isochronous droop curve; a top droop curve; and a bottom droop curve. The method includes performing command according to the droop curves; registering that the vehicle soon will enter an uphill slope; estimating in a vehicle position before entering the uphill slope if a downshift in a transmission of the vehicle will occur when traveling the uphill slope during a coming time period (testimation); if the downshift is estimated to occur then performing a fuel saving action during the time period in order to avoid the downshift. The fuel saving action is one of an adaptation of transmission downshifting limits or to during the time period performing command according to a second isochronous curve.

A method for determination of one or more downshift and upshift points for a gearbox in a motor vehicle. The vehicle includes an engine connected to the gearbox, where a downshift point represents a first engine speed at which the gearbox effects a downshift, and an upshift point represents a second engine speed at which the gearbox effects an upshift. One or more downshift and upshift points are determined relative to an engine target speed which is a desired speed for the engine. A system, a motor vehicle, a computer program and a computer program product thereof perform the method.

The invention discloses a method for controlling a manual mode of an automatic transmission with a gear shifting piece. By setting manual mode entry condition and manual mode exit condition, when manual mode activation flag bit is TRUE, upshift, downshift or skip control is carried out on current gear through comprehensive judgment, and engine is made to work within effective engine rotating speedrange. By means of the manual mode control method, manual mode switching of the CVT can be achieved, drivability is improved, hardware cost does not need to be increased, even if a driver suddenly overtakes a full accelerator, a transmission controller can automatically recognize and automatically skip to shift gears, and driving pleasure and driving safety are greatly improved.

The invention provides a gear selection method and system for a hybrid vehicle, electronic equipment and a storage medium. The method comprises the steps that the current driving state of a vehicle and the working condition of an engine are determined; if it is determined that the vehicle is in the running state and the engine is in the shutdown working condition, an engine rotating speed limitinggear is obtained according to the current vehicle condition and the rotating speed of a transmission input shaft of each gear corresponding to the current vehicle speed; the vehicle conditions comprise accelerator pedal opening degree, vehicle speed, braking condition, engine idling speed and rotating speed; an acceleration mode of the vehicle is determined according to the accelerator pedal opening degree; if the acceleration mode is full-accelerator acceleration, a downshift mode after full-accelerator acceleration is obtained according to the vehicle speed; and if the downshift mode is coaxial downshift, the engine rotating speed limiting gear is lowered by a set gear, and a target gear when the engine is started is obtained. According to the method, selection of the target gear can bebetter matched with the rotating speed of the engine, and the problem of power delay caused by too low gear selection or the target gear in the gear shifting process is avoided.

This vehicle control device 10 is provided with: a current gear stage selection unit 13 which selects a current gear stage, which is the gear stage of the vehicle in the present travel state; a travel segment determination unit 15 which determines the next travel segment forwards in the direction of travel of the vehicle V; and a shift control unit 17 which, in the case that the current gear stage selection unit 13 has newly selected a target gear stage lower than the current gear stage during travel of the vehicle V in the current gear stage in the current travel segment, if the next travel segment can be traveled in the current gear stage and the amount the vehicle V will lose speed after traveling the current travel segment is less than or equal to a prescribed threshold value, controls shifting of the gear stage such that downshifting from the current gear stage to the target gear stage is suppressed and the current gear stage is maintained. Even in a state in which downshifting is suppressed, if the state of the vehicle the satisfies a prescribed condition, then the shift control unit 17 controls shifting of the gear stage so as to downshift to the target gear stage without suppression of downshifting.

A controller for a hybrid vehicle predicts whether necessary discharging electric power from a power storage device which is required to perform downshift in a transmission exceeds upper-limit discharging electric power of the power storage device when downshift in the transmission is performed in a hybrid vehicle travel mode and controls a compressor rotation speed such that a rate of increase of the compressor rotation speed of a supercharger at the time of performing downshift in the transmission increases as the upper-limit discharging electric power decreases when it is predicted that the necessary discharging electric power exceeds the upper-limit discharging electric power.

The invention discloses a gearbox gear shifting control method. The gearbox gear shifting control method comprises the following steps that 1, the current accelerator stepping speed and the actual accelerator opening degree of a target vehicle are obtained; 2, according to the current accelerator stepping speed, the actual accelerator opening degree is adjusted to be the virtual accelerator opening degree, and the virtual accelerator opening degree serves as the first virtual accelerator opening degree or the second virtual accelerator opening degree; 3, a target gear of a gearbox in the target vehicle is determined according to the virtual accelerator opening degree; and 4, the gearbox is adjusted to the target gear from the current gear. According to the gearbox gear shifting control method, gearbox gear shifting according to the actual accelerator opening degree is changed into gearbox gear shifting according to the virtual accelerator opening degree, the probability of continuous downshifting is reduced due to the fact that gearbox gear shifting is conducted according to the virtual accelerator opening degree, the situation that a transmission system is in a power interruptionstate due to frequent gear shifting is avoided, and the problem that a driver continuously steps on an accelerator and the vehicle does not have an acceleration feeling is solved.

A method, a system, a computer program and a computer program product for determining one or more shift points for a gearbox in a motor vehicle which comprises an engine connected to, in order to drive the gearbox. A shift point is defined by an engine speed at which the gearbox effects a downshift or upshift. The method uses one or more shift points determined on the basis of a change in road gradient.

A retarding unit in a vehicle is automatically controlled based on conditions including a current setting of the retarding control, downhill grade, speed, current gear, and impending gear change. With the retarder control set in the high position, when the vehicle is operating at a downhill angle greater than the low angle threshold and less than the high angle threshold, and the pending gear is a large step downshift, automatically setting a retarder level to a low retarder level. When the vehicle is operating on level ground and the pending gear is a large step downshift or the current gear is first or second gear, automatically setting the retarder level to off. When the vehicle is operating on flat ground and the deceleration is above a trigger level, automatically setting the retarder level to a low retarder level.

The invention discloses a downshift deceleration compensation method and device, a vehicle and a storage medium. The method comprises the steps of sending a motor downshift request to an automatic gearbox control unit; receiving a motor torque unloading request sent by the automatic gearbox control unit; sending a motor unloading torque request to an integrated combined power device to control a motor unloading torque; in the process that the integrated combined power device makes the motor unload the torque, acquiring a current target recovery torque, a current target stable torque and a motor transmission ratio before downshift, wherein the target recovery torque includes the torque determined based on a current vehicle speed; determining a target brake torque based on the current targetrecovery torque, the current target stable torque and the motor transmission ratio before downshift; and sending the target brake torque to a vehicle body electronic stability control system so as tocompensate a braking force for the vehicle based on the current acceleration and the target brake torque. By utilizing the technical scheme provided by the invention, smoothness of downshift deceleration can be improved, and a potential safety hazard of driving is reduced.

The invention relates to a vehicle control method, a vehicle control device and a vehicle, and aims to increase a coasting distance of the automatic transmission vehicle and reduce a sense of abruptness generated when a driver presses an accelerator to accelerate during deceleration and downshifting. The vehicle control method comprises the steps of controlling a lock-up clutch of the vehicle to be in an open state during coasting of the vehicle so as to disconnect an engine of the vehicle from a transmission system, judging whether an accelerator pedal signal of the vehicle is detected, determining a gear position which matches a current vehicle speed when the accelerator pedal signal is detected, and controlling a state of the lock-up clutch and a torque response time of the engine according to the gear position so as to enable the vehicle to shift to the gear position and travel in the gear position.

The invention discloses a vehicle locking control method and system, a vehicle and a storage medium, and belongs to the technical field of vehicle control. The method comprises the steps of s1, whether a bicycle locking instruction is received or not is judged, if yes, a current gear is recorded as a memory gear, the current gear is monitored in real time, and the step S2 is executed; s2, whetherthe clutch is in a treading state or not is judged, and if not, the step S3 is executed; s3, whether the current gear is smaller than or equal to the lowest limiting gear or not is judged, if yes, theengine torque is not limited, and if not, the step S4 is executed; and s4, whether the current gear is smaller than or equal to the memory gear or not is judged, if yes, the engine torque is not limited, the memory gear is updated to be the current gear, and if not, the engine torque is limited to maintain idling. The mode that the engine torque is limited to be kept at the idle speed through different gears is adopted, upshifting of the vehicle is limited, only the gear and downshifting can be kept, driving safety and gear shifting safety are guaranteed, the heavy-load vehicle moving requirement of the vehicle can be met, and the use experience of a user is improved.

The invention discloses a gear control method and system for an automatic gearbox of a loader. The method comprises the steps of increasing or decreasing delta n on an upshift preset condition betweentwo gears before and after downshift when the loader climbs and downshifts in an automatic gear shifting mode of the gearbox, so that the upshift is more difficult after downshift; and meanwhile, after the gearbox is automatically upshifted, the downshifting preset condition between the front upshifting gear and the rear upshifting gear is increased or decreased by delta m, and downshifting is more difficult after upshifting. According to the method, the gear information before and after gear shifting is recorded, and the gear shifting strategy is adjusted, so that the gear is more stable when the loader climbs a slope, and the problem of repeated upshifting and downshifting is solved.

For a hybrid vehicle including an engine, a motor generator, and a belt-type continuously variable transmission, a controller performs a low speed position return expediting control in response to a downshift request accompanying deceleration. During the low speed position return expediting control, the controller increases a differential pressure between a primary pressure and a secondary pressure and cause a downshift toward a lowest speed position transmission ratio by reducing the primary pressure, and further reduces the primary pressure when the secondary pressure becomes greater than or equal to a trigger threshold value during the downshift; and terminates the low speed position return expediting control when an actual secondary pressure decreases to a secondary pressure minimum level. The controller further sets a secondary pressure lower limit higher than the secondary pressure minimum level during the low speed position return expediting control.

The invention relates to a fuel cut-off gear shifting control method and device for a vehicle, electronic equipment and a storage medium. The fuel cut-off gear shifting control method for the vehiclecomprises the steps that the fuel supply state of an engine of the vehicle is detected; if the vehicle engine is judged to be in the fuel cut-off state, whether the vehicle meets set conditions is detected, wherein the vehicle meets the set conditions that an air conditioner of the vehicle is turned on, the vehicle runs in a plateau environment or the vehicle is braked suddenly; if it is judged that the vehicle meets the set conditions, the fuel cut-off compensation rotating speed of the engine is obtained, wherein the fuel cut-off compensation rotating speed is larger than the corresponding engine fuel supply recovery rotating speed under the set conditions; and a downshift node of the vehicle is controlled according to the fuel cut-off compensation rotating speed. By means of the technical scheme, the corresponding engine rotating speed during vehicle downshifting is corrected in real time, so that the engine operates above the oil supply recovery rotating speed of the engine, the situation that oil supply of the vehicle is recovered in advance after the vehicle is powered off under the special working conditions such as air conditioner starting, plateau environment and sudden brake stepping is avoided, and then vehicle oil consumption is reduced.

The invention provides an engine overspeed protection control method and system and an engineering vehicle. The engine overspeed protection control method specifically comprises the steps that current gear information and target gear information are obtained; the rotating speed of the target gear information is calculated based on the gear information; and determining the rotating speed of the target gear and the maximum rotating speed allowed by the target gear information so as to determine the gear change of the gearbox. The vehicle speed is ensured to be stable during downhill, the rotating speed of the engine is prevented from being too high, and overspeed caused by reverse dragging of the engine in the downhill process is avoided. And meanwhile, the completion of the upshift operation is displayed, the driver is reminded that the upshift operation is completed, the rotating speed of the transmission mechanism is judged when the driver performs the downshift operation, and the downshift operation can be performed when the rotating speed of the transmission mechanism is not overspeed after the downshift operation is determined. Under the condition that the safety of the vehicle is guaranteed, a driver can make appropriate operation or prevent the situation that the rotating speed of an engine is too large due to wrong downshift operation of the driver.

A fuel-saving control device equipped with: a surplus drive force calculation unit for calculating surplus drive force; a fuel-saving control unit for executing a fuel-saving control which lowers and corrects the indicated fuel injection amount according to the accelerator position when the surplus drive force reaches or exceeds a threshold, and stopping the fuel-saving control when the surplus drive force falls below the threshold; a vehicle position detection unit for detecting the vehicle position; a map information storage unit for storing map information; a downshift operation detection unit for detecting a downshifting operation; and a forward gradient identification unit for identifying the forward gradient on the basis of the vehicle position and the map information. Therein, the fuel-saving control unit stops the fuel-saving control when a downshifting operation is detected and the forward gradient is an uphill grade equal to or greater than a threshold.

A controller includes a control unit configured to perform stepwise shift that upshifts a CVT in a stepped manner to accelerate a vehicle. The control unit performs a downshift control configured to downshift the continuously variable transmission in a case in which an accelerator pedal is continuously stepped on from before prohibition of the stepwise shift to after prohibition of the stepwise shift.

Systems and methods for improving gradeability of a hybrid electric vehicle are described. More particularly, an electric motor of the hybrid electric vehicle may be used to augment engine torque generated by an internal combustion engine of the hybrid electric vehicle with motor torque generated by the electric motor during periods when a desired acceleration of the hybrid electric vehicle demands a target driveforce that exceeds a maximum driveforce generated by the internal combustion engine at a particular gear ratio of the transmission of the hybrid electric vehicle. Augmenting the engine torque with the motor torque during such periods of acceleration may delay a downshift of the transmission to a lower gear ratio thereby improving a driver experience.