I. Experimental objectives
Trainees are fluent in the failure and overhauling of automatic transformers。
Ii. Examination points
The failure and overhaul of the automatic transformer。
Iii. Experimental environment and experimental tools
1. Disk training hall
2. 52 tools set
Iv. Experimental requirements
Experimental phenomena: the system cannot achieve automatic switch-to-turn speeds based on the size and speed of the gas doors。
Testing process:
Classification of liquid mechanical automatic transformers:
Liquid mechanical automatic transformers can be divided into liquid controlled liquid automatic transformers and electricly controlled liquid automatic transformers by the control of the gear transformer system。
1. There are three types of information in the hydraulic transformer hydraulic control system to control the automatic switch: change of handle position, opening of the oil door, speed of car. When the driver selects the position to change the handle, the control system will achieve the automatic switch rate according to the level of the door and speed。
Following the selection of the position of the hand control valves, the air-saving valves, reflecting the opening of the gas-saving doors, and the speed-referral valves, transform the openings and speeds of the gas-saving doors from mechanical motion to hydraulic control signals, which, at the change point, are directly controlled by the control valves in the hydraulic control valves, which allow the switch-over to pass through the enforcement agency。
The liquid-controlled liquid automatic transformer is large in capacity, responsive, easy to manipulate, easy to automate and easy to secure, but the construction precision of hydraulic system components is high, complex in structure, and failure is not easy to detect and remove. Automatic transformers until the 1970s should be liquid-controlled liquid-activated circuits and are now widely used, as shown in figure 44-1。
2. After the selection of the hand control valves, the electro-controlled liquid transformer, by means of an air-saving door position sensor reflecting the opening of the gas-saving door and a speed-resistor reflecting the speed of the vehicle, turns the gas-saving door openings and speed-reverse telecommunication numbers into the electronic control unit (ecu), at the change of block, the euu sends the telecommunications number to the switch-shielding magnetic valves, the oil-pressure magnetic valves, the locked electromagnetic valves, and the electro-magnetic valves convert the telecommunications code into a hydraulic control signal, with the hydraulic control signal control hydraulic pressure valves having various transformer valves in place of the replacement enforcement agency。
The electro-controlled liquid automatic transformer consists of a liquid rectifier, a planetary gear transformer system, an auto-shield manoeuvre system, a transformer shell and a oil cooler system. Liquid rectifiers and planetary gear transformers are the necessary conditions and the structural basis for the formation of automatic transformers, while the automatic switch control system is central and technical to the automatic transformers. In liquid rectanglers, in order to avoid the adverse effects of hydraulic oil and gas erosion and high temperatures, it is necessary to set up a compensatory pump to transport the working liquid to the rectangular at a certain pressure and to maintain a compensatory pressure within the circle: another function of the compensatory pump is to constantly extract the work fluid from the rectangular to cool the oil casing of the cooler or speed transformer。
An increasing number of vehicles now use electro-controlled liquid automatic transformers, which have the following advantages compared to liquid controlled liquid automatic transformers:
3. Computation allows for the storage and processing of multiple alternation patterns, thus achieving more rational and complex controls, breaking the hydraulic valve structural limitations, and achieving a more desirable fuel economy and power。
4. Simplified hydraulic manipulation systems with compact structures and light weight。
Control accuracy is high, reflects speed and is accurate。
6. Compatibility with electronic controls of other systems in automobiles, such as engine control, cruise control, towed control, brake control against death, 4x4 control, etc。
When the automatic removation system changes the pattern or parameters of the block, only changes in the control procedures and the model specifications of certain electronic components are required, and no changes are required in the transmission structural parts, so they are adaptable and have a short development cycle, and they are more visible in the series of products。
Zhengzhou's expert at the wantung automobile school advised the owner of the car that the failure had been resolved。
