ASU (Air Supply Units for air suspension) is a core subsystem of automotive air suspension systems. By generating, storing, and regulating compressed air, it enables dynamic control of suspension height, stiffness, and damping, thereby improving vehicle comfort, handling, and off-road capability.

Its main functions include:

1.Supplying stable high-pressure air to support vehicle weight and adjust suspension travel;

2.Dynamically regulating air pressure according to driving conditions;

3.Preventing abnormal states such as overpressure, overheating, or air leakage to ensure system reliability.

The air suspension supply system primarily consists of four parts: the air source module, control module, actuation module, and auxiliary components:

Air source module: responsible for air pressure generation and storage. The air compressor compresses ambient air to high pressure, operating on-demand with built-in overload protection. The air tank stores high-pressure air to reduce compressors recycling and stabilize air pressure output. The air dryer removes moisture from compressed air to prevent freezing or corrosion during winter.

Control module: Handles signal processing and logic control. The ECU/TCU receives sensor data, calculates target pressure and controls solenoid valve actions. It implements closed-loop height control, stiffness adjustment, overpressure relief (via safety valve), compressor thermal shutdown, and leak detection alerts. The pressure regulator reduces high-pressure air from the air tank to working pressure suitable for air springs, preventing damage from overpressure.

Actuation module: Manages air distribution and regulation. The solenoid valve set directs air flow through inflation, deflation, and pressure-holding operations, with individual solenoid valves for each air spring. Some vehicles include mechanical lock valves that maintain pressure when powered off. Air lines.

Auxiliary components include: Safety Valve, Exhaust Muffler, Filters and filter elements, which enhance system reliability and performance.

Working principle of the ASU Air Supply System:

Height sensors continuously monitor vehicle posture, acceleration sensors detect road impact signals, pressure sensors measure air tank pressure. The ECU integrates these data and driving modes to form control strategies. Based on algorithms, it automatically inflates or deflates air springs to maintain the vehicle at a preset height, ensuring optimal working conditions for the air suspension.

Example operations:

Vehicle raising (inflation process): When increased load lowers the body height, the sensors detect the drop, and the ECU opens the solenoid valves to inflate the air springs. The rising pressure lifts the vehicle until the target height is reached, then the valves close to maintain the height.

Vehicle lowering (deflation process): When reduced load causes the body to rise, the ECU opens the valves to release air. The pressure drop lowers the body until the desired height is reached, after which the valves close.

Air spring pressure directly affects suspension stiffness:

Higher pressure → firmer springs → better handling

Lower pressure → softer springs → better ride comfort

A closed-loop control algorithm (e.g., PID) ensures height deviation stays within ±3 mm and minimizes compressor cycling to extend system lifespan.

Technique features and advantages of the Air Suspension Supply System:

Active Adjustment & Dynamic Response: Real-time monitoring via height and pressure sensors combined with ECU control enables quick and precise adjustment of air pressure, ride height, and suspension stiffness.

Modular & Integrated Design: Core components such as the compressor, air tank, solenoid valves, and sensors are highly integrated for a compact layout, suitable for various vehicle platforms. Lightweight materials ensure pressure resistance while reducing system weight and improving energy efficiency.

Stable Pressure & Safety Protection: The air tank provides a stable pressure reserve, reducing compressor start/stop frequency and extending component lifespan. Safety valves protect against overpressure. Fault detection features (e.g., for air leaks, overheating, or sensor failure) trigger automatic protection mechanisms and alerts.

Through “real-time sensing, intelligent decision-making, and precise execution”, the ASU air suspension system enables active control over ride height and suspension characteristics. Compared to traditional suspension systems, it offers clear advantages in comfort, load adaptability, and smart functionality.

HOLS Automation has years of expertise in industrial automation, backed by a strong technical team and R&D capabilities. The company offers intelligent manufacturing solutions for chassis suspension systems, including: Automated Air Spring Dampers Production Line, Air Suspension Supply System Assembly Line, Air compressor Assembly Line, Automated Chassis Domain Controller Production Line, etc.