AIRmatic, function - GF32.22-P-0003GZ: Notes

MODEL 164.1 /8 with CODE (489) Airmatic (air suspension with level adjustment and adaptive damping system ADS) 

"AIRmatic with ADS" is a fully supporting air suspension system. 

This means that both the suspension and damping can be adjusted Apart from this the automatic level control and selectable level adjustment are performed. The adaptive damping system (ADS) is available with a 3-stage optional damper setting, which operates according to the skyhook algorithm. The ADS regulates the vehicle damping system to match the driver's commands, vehicle body acceleration and additional parameters.

Base function 

When the air compressor delivers air to a bellows, the vehicle level increases at the wheel concerned. Conversely, the vehicle level decreases if air escapes into the atmosphere through the pressure release valve of the AIRmatic compressor unit (A9/1). The system is equipped with a central reservoir as a compressed-air reservoir. This increases the adjustment speed when raising the vehicle and permits regulation in the sleep and run-on mode. In addition AIRmatic is combined with an automatic electronically controlled damper adjustment.

The complete function of AIRmatic can be subdivide d into 3 subfunctions: 

• Level control  enables a manual, as well as a speed-dependent automatic raising or lowering of the vehicle level.
• The electronic level control system  controls the vehicle level at the front and rear axles and ensures the vehicle level remains constant according to the driving and vehicle loading conditions.
• The "adaptive damping system" (ADS)  adapts the damping forces to the road surface condition and driving style or driver's wishes. The road conditions are determined by vertical acceleration pickups at the body of the vehicle. The driving style is calculated from the vehicle speed and the steering angle. As the speed increases and the driving style becomes sportier the damping is automatically adjusted to a harder damping characteristic. Compared to a passive system with conventional dampers the vehicle body motion is cut down noticeably.

Advantages of AIRmatic 

Greater driving safety and ride comfort due to:

• Speed-dependent level control. An increase in ride comfort is achieved through softer base suspension at low speeds and with normal driving styles;
• When lowering the vehicle level and changing the damping characteristic of the ADS for a sporty driving style and at higher speeds, no compromises in vehicle dynamics have to be made;
• Adaptation of suspension to road surface condition and driving style;
• Adaptation of damping to road surface condition and driving style;
• Reaching a lower center of gravity position;
• Reaching a lower aerodynamic drag and thus a lower fuel consumption;
• Less lift at front axle.
• An individual adaptation by increasing the vehicle level for poor roads or when offroad.
• Adjusting option for 3 damping stages;
• Mercedes-Benz Driver Information Service through display of raised and lowered vehicle level stages, damping stage by way of function indicator lamps in the switches, and a warning for a vehicle level that is too high by the multifunction display (A1p13) in the instrument cluster (A1).

Function overview 

The corresponding functions of the pneumatic closed loop of the AIRmatic and of the electrohydraulic closed loop of the adaptive damping system (ADS) are controlled by the electrical and electronic components.

The AIRmatic control unit receives input signals  from the following components via the CAN data bus:

• ESP control module (N47-5) (wheel speed signal and stop lamp switch signal)
• ME-SFI [ME] control unit (N3/10)
• Fully integrated transmission control (VGS) control unit (Y3/8n4) (target and actual gear)
• Central gateway control unit (N93)
• Instrument cluster (A1) (outside temperature and circuit 61 "engine running")
• Steering angle sensor (N49) (signal over steering column module (N80) on CAN engine compartment)
• Comfort/Sport switch (ADS) (N72/1s31)
• Level adjustment switch (N72/1s2)

The AIRmatic control unit receives input signals from the following components via discrete inputs:

• Left front body lateral acceleration sensor (B24/3)
• Right front body acceleration sensor (B24/4)
• Right rear body lateral acceleration sensor (B24/6)
• Left front level sensor (B22/8)
• Right front level sensor (B22/9)
• Left rear level sensor (B22/7)
• Right rear level sensor (B22/10)
• AIRmatic pressure sensor (Y36b1)

The AIRmatic control unit controls the following control functions on the basis of the input signals: 

• Level control
• Level adjustment
• Adaptive damping system (ADS)

Several control functions can be processed at the same time.

In the AIRmatic control unit (N51) the input signals are converted into output signals for the following components: 

Actuators of the Adaptive Damping System (ADS) 

• Left front axle damping valve unit (Y51) 
  • Solenoid valve 1, left front (Y51y1)
  • Solenoid valve 2, left front (Y51y2)
• Right front axle damping valve unit (Y52) 
  • Solenoid valve 1, front right (Y52y1)
  • Solenoid valve 2, front right (Y52y2)
• Left rear axle damping valve unit (Y53) 
  • Solenoid valve 1, rear left (Y53y1)
  • Solenoid valve 2, rear left (Y53y2)
• Right rear axle damping valve unit (Y54) 
  • Solenoid valve 1, rear right (Y54y1)
  • Solenoid valve 2, rear right (Y54y2)

Actuators of level control and level adjustment 

• Air compressor motor (A9/1m1) via AIRmatic relay (K67)
• AIRmatic pressure reduction valve (A9/1y1)
• AIRmatic valve unit (Y36)

For driver information 

• Multifunction display in instrument cluster
• Indicator lamps in Comfort/Sport switch (ADS) and in level adjustment switch

	AIRmatic driver information	Except offroad package, code 430	GF32.22-P-0003-01GZ
		With offroad package, code 430,	GF32.22-P-0003-01GZA
	AIRmatic - location of the electrical / electronic components		GF32.22-P-0003-03GZ
	Adaptive damping system (ADS), function		GF32.32-P-0002GZ
	Level adjustment, function		GF32.22-P-4005GZ
	AIRmatic level adjustment, function	Model 164.1 except USA version, code 494, except offroad package, code 430	GF32.22-P-4004GZ
		Model 164.1 except USA version, code 494, with offroad package, code 430	GF32.22-P-4004GZE
		Model 164.1 /8 with USA version, code 494, except offroad package, code 430	GF32.22-P-4004GZU
		Model 164.1 with USA version, code 494, with offroad package, code 430	GF32.22-P-4004GZV
		Model 164.8 with USA version, code 494, with offroad package, code 430	GF32.22-P-4004GZW
	Pressure supply, function		GF32.22-P-4010GZ