Suspension Control ( Automatic - Electronic ): Description and Operation

System Outline

This system is a combined system of the vehicle height adjustment system and the damping force control system.

1. Input Signals
1. Height control sensor signal
The vehicle height and the distance between the tire and body frame is detected, and is input to suspension control ECU TERMINALS SHFL, SHFR, SHRR.

2. Fluid pressure sensor signal
The hydraulic pressure is detected, and the signal is input to suspension control ECU TERMINAL PACC.

3. Temperature sensor signal
The fluid temperature is detected, and the signal is input to suspension control ECU TERMINAL TOIL.

4. Height control SW signal
Detects the changes in the target vehicle height, and the signal is input to suspension control ECU TERMINALS DNSW, UPSW.

Detects the changes in the vehicle height control, and the signal is input to suspension control ECU TERMINAL NSW.

5. Differential lock detection SW signal
Detects the differential lock, and the signal is input to suspension control ECU TERMINAL EXI.

6. L detection SW signal
Detects the transfer gear L, and the signal is input to suspension control ECU TERMINAL L4SW.

7. Stop light SW signal
Detects the brake signal, and the signal is input to suspension control ECU TERMINAL STP.

8. Generator signal
Detects whether the engine is running or not, and the signal is input to suspension control ECU TERMINAL REG.

9. Door courtesy SW signal
Detects whether the door is open or closed, and the signal is input to suspension control ECU TERMINAL DOOR.

10. Steering sensor signal
Detects the rotation number of the steering wheel, and the signal is input to suspension control ECU TERMINAL SS2+, SS2-

11. Wheel speed sensor signal
Detects the wheel speed signal, and the signal is input to suspension control ECU TERMINAL FLO, FRO.

12. Damping mode select SW signal
Detects whether the damping force mode is selected or not, and the signal is input to suspension control ECU TERMINALS TSW1, TSW2.

13. Intelligent tester communication signal
The intelligent tester requirement signal is sent to suspension control ECU TERMINAL SIL. The suspension control ECU also sends back a signal to the intelligent tester.

2. Vehicle Height Adjustment Function
1. Vehicle height adjustment by the SW
By operating the SW, the vehicle height can be adjusted to three heights, low, normal, and high.

2. Automatic leveling function
The vehicle height is maintained at a certain level when the load is within the specified load capacity.

3. Vehicle speed detection function
The height is adjusted automatically in response to the vehicle speed.

4. Extra HI mode
In L range with the height at HI mode, the height is raised 20 mm automatically, when the wheels are idling on a bumpy road surface.

5. Vehicle height control SW
When the vehicle height control SW is turned off, the vehicle height control functions could be inhibited.

3. Damping Force Control Function
1. Bouncing control
The front and rear wheels are independently controlled electronically, to ensure adequate damping force at all times, in response to the bumpy road surface.

2. Harshness control
The damping force is controlled not to increase when the road condition does not require damping force, to ensure smooth and comfortable riding.

3. Unsprung vibration control
When unsprung sympathetic vibration is detected, the damping force is controlled so that it does not decrease below a certain level, to prevent such vibration and converge it, to ensure road holding.

4. Vehicle speed sensing control
To ensure optimal balance of comfortable riding and road holding, the minimum damping force is increased as the vehicle speed increases.

5. Anti-roll control
When the driver makes a turn, the damping force is controlled electronically according to the condition, and slows down the vehicle rolling speed.

6. Anti-dive control
The vehicle dive condition is detected at an early stage through braking and the vehicle wheel speed signal, and the damping force is controlled according to the condition, to slow down the dive speed when decelerating.

7. Anti-squat control
The vehicle squat condition at acceleration is detected at an early stage, and the damping force is switched to a higher level to avoid squat.

8. Damping mode select SW
The damping mode select SW has 4 modes, and can be changed according to the driver preference.

4. Wheel Disconnection Function
Usually the right and left wheels are connected, but when the driver turns the steering wheel, the wheels are disconnected in response to the condition. This is to prevent roll angle increase when making a turn.