ELECTRONIC CONTROL TRANSMISION, LE THANH PHUC
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ELECTRONIC CONTROL TRANSMISSION
Le Thanh Phuc
Faculty of Automotive Engineering
University of Technical Education Ho Chi Minh City
Email:
Introduction
•
The Electronic Control Transmission is an automatic transmission which uses electronic technology to control
transmission operation.
•
•
The transmission is virtually the same as a fully hydraulic controlled transmission.
It includes electronic solenoids, sensors, and an electronic control unit.
2
Introduction (Cont’d)
•
The electronic sensors monitor the speed of the vehicle, speed of the input shaft, gear position selection and throttle
opening, providing this information to the ECU.
•
The ECU then controls the operation of the clutches and brakes based on this data and controls the timing of shift
points and torque converter lock-up and maintains on-board diagnosis.
3
Planetary Gear Set
•
The planetary gear unit is used to increase or decrease engine torque, increase or decrease vehicle speed, reverse
direction of rotation or provide direct drive.
•
It is basically a lever that allow the engine to move heavy loads with less effort.
4
Planetary Gear Set
5
Multiplate Clutch
•
The multiplate clutch connects two rotating components of the planetary gear set.
•
Because this assembly rotates while the vehicle is in motion, it presents a unique challenge to ensure fluid under
pressure reaches the clutch and holds the clutch engaged for thousand of miles of services.
6
Multiplate Clutch
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Band Brake
•
The brake band is located around the outer circumference of the direct clutch drum.
•
One end of this brake band is located to the transmission case with a pin, while the other end contacts the brake
piston which is operated by hydraulic pressure.
8
Band Brake
9
One-way Clutch
•
One-way clutch is a holding device which requires no seals or hydraulic pressure to apply.
•
Their operation is similar in that they both rely on wedging metal between two races.
10
One-way Clutch
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First Gear
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Second Gear
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Third Gear
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Reverse Range
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Neutral Start Switch
•
The ECU receives information on the selected gear range from the shift position sensor, located in the neutral start
switch, and determines the appropriate shift pattern.
•
The neutral start switch is actuated by the manual valve shaft in response to gear selector movement.
16
Neutral Start Switch
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Throttle Position Sensor
•
This sensor is mounted on the throttle body and electrically senses how far the throttle is open and then sends this
data to the ECU.
•
By relaying the throttle position, it gives the ECU an indication of engine load to control the shifting and lock-up
timing of the transmission.
18
Throttle Position Sensor
19
Engine Coolant Temperature Sensor
•
The engine coolant temperature sensor monitors engine coolant temperature and is typically located near the
cylinder head water outlet.
•
A thermistor is mounted within the temperature sensor, and its resistance value decreases as the temperature
increases.
•
When the engine coolant is below a predetermined temperature, the engine performance and the vehicle’s
driveability would suffer if the transmission were shifted into overdrive or converter clutch were locked-up.
20
Engine Coolant Temperature Sensor
21
Speed Sensor
•
The speed sensor signal originates from a sensor measuring transmission/transaxle output speed or wheel speed.
•
Different types of sensors have been used depending on models and applications.
•
On some vehicles, the vehicle speed sensor signal is processed in the combination meter and then sent to the ECU.
22
Speed Sensor
23
Stop Light Switch
•
The stop light switch is mounted on the brake pedal bracket.
•
When the brake pedal is depressed, it sends a signal to the STP terminal of the ECU informing it that the brakes have
been applied.
•
The ECU cancels torque converter lock-up when the brake pedal is depressed.
24
Stop Light Switch
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