The development of lock-up clutches
With the continuous development of automatic transmission technology, only relying on simple hydraulic control or electrical control to engage or disengage the lock-up clutch has exposed many problems. Therefore, the American General Motors Company took the lead in adopting the electronic control of the lock-up clutch in 1891, and other automobile manufacturers soon followed. So far, it can be said that almost all hydraulic lock-up clutches have adopted electronic control.
For the electronically controlled lock-up clutch, the action of the lock-up piston is controlled by the lock-up solenoid valve and one or several sliding plunger valves. When the lock-up occurs or is released, the solenoid valve controls the sliding plunger. The oil pressure signal of the valve action, and the sliding plunger valve really controls the oil pressure that makes the clutch piston engage and disengage. Since the electronic control methods or methods of automatic transmission lock-up clutches of major automobile manufacturers have their own characteristics, a few representative ones are selected and introduced below.
Chrysler Automobile Company’s lock-up clutch electronic control
Chrysler Automobiles adopted electronic control of the lock-up clutch in 1986. The hydraulic oil circuit part of the control system, and its lock-up solenoid valve is controlled by the electronic control unit through a lock-up clutch relay. As for the signal sources that the electronic control unit relies on to determine whether to lock or not, they are the cooling water temperature sensor, the vacuum sensor, the vehicle speed sensor, and the throttle closing switch. Normally, only when the engine cooling water temperature is higher than 6o6C, the vehicle speed is higher than 6k4m/h, and the engine intake manifold vacuum is about 26.66-66.66kPa, lock-up can occur. When the engine cooling water temperature indicated by the water temperature sensor rises above 66°C, the electronic control unit can determine whether to lock the lockup clutch in the torque converter according to the signals from the throttle closing switch, vehicle speed sensor and vacuum sensor .
Whenever the throttle closing switch is in the closed state, the electronic control unit will not energize the lock-up solenoid valve and therefore will not lock the clutch. There is no doubt that the function of this switch is to notify the electronic control unit to release the lock of the lock-up clutch. In order to reduce exhaust pollution and increase fuel economy when the throttle is closed and slowing down.
In order to prevent the lock-up solenoid valve from being energized and de-energized repeatedly during the brief opening and closing of the throttle valve, there is a part of the electronic control unit program to ensure that the engagement action of the lock-up clutch is delayed for a given period after the throttle closing switch is turned on. time. For automotive parts and parts machining, PTJ Shop offers the highest degree of OEM service with a basis of 10+ years experience serving the automotive industry. Our automotive precision shop and experts deliver confidence. We have perfected the art of producing large component volumes with complete JIT reliability, backed by the quality and long-term reliability our customers expect.