Hydromechanical automatic transmission (automatic transmission)
A hydromechanical automatic transmission is a type of automatic transmission that uses hydraulic pressure and mechanical components to change gears. Here are the main characteristics and components of a hydromechanical automatic transmission:
Working principle:
* A hydromechanical automatic transmission uses hydraulic pressure to operate clutches, called clutch packs, to change gears.
* The transmission of hydraulic pressure is initiated by the Electronic Control Unit (ECU), which receives signals from various sensors such as the engine speed sensor, throttle position sensor and transmission fluid temperature sensor.
* The ECU sends signals to solenoids that open or close hydraulic passages, directing pressure to the corresponding clutch packs.
Components:
Hydraulic transformer:
* The hydraulic transformer is located between the engine and transmission and serves to multiply the engine torque. It also acts as a clutch, allowing the engine to idle when the car is stationary.
Clutch packages:
*Clutch packs are mechanical components that are used to change gears by interlocking various elements of the transmission. They include:
*Direct Drive Package (transmits power directly from engine to transmission)
* Reverse package (transmits power in reverse direction)
* Planetary gear packages (used for different gear ratios)
Planetary gears:
* Planetary gears are used to change the transmission ratio. They consist of a central sun gear, planetary gears rotating around the sun gear, and a ring gear.
Hydraulic valve block:
* The hydraulic valve block is responsible for controlling the hydraulic pressure circulating in the transmission. Contains solenoids that open or close hydraulic passages, directing pressure to the corresponding clutch packs.
Advantages:
* Smooth gear shifting
*Good fuel efficiency
*High torque at low speeds
* Suitable for use in a variety of applications including cars, trucks and four-wheel drive vehicles
Flaws:
* More complex design compared to other types of automatic transmissions
* The need for regular maintenance and replacement of transmission fluid
*May be less efficient than other types of automatic transmission at high speeds
*Higher production cost