ArvinMeritor
Meritor WABCO Vehicle Control Systems has announced at the the Mid-America Truck Show, its new tractor and trailer electronic leveling modules (ELM). The modules are designed to electronically sense and accurately control the operation of the tractor and trailer air suspensions.

The primary function of the modules is to supply air to the respective suspension on an as-needed basis only. This results in optimum control of ride height with minimal parasitic compressor load on the engine. Minimal parasitic power loss translates into increased pulling power and reduced fuel consumption.

The tractor ELM raises and lowers the rear air suspension by means of a dash-mounted switch or an optional remote control. After the trailer is uncoupled and the tractor begins to drive away, the module automatically returns the suspension to the optimum ride height.

With the trailer ELM, a control pad allows the vehicle operator to quickly raise or lower the trailer at the loading dock. After loading/unloading is complete and the tractor-trailer begins moving away from the dock, the ELM automatically returns the trailer to the optimum ride height. This helps reduce suspension bottoming and prevents damage to the trailer.

An electronic inductive sensor, integral to both models, provides precise measurement of the vehicle ride height. To keep the tractor-trailer combination running level, an electronic control unit (ECU) analyzes ride-height changes every sixty seconds before supplying air to the suspension or exhausting it. With less air being consumed by the air suspension, the compressor loads and unloads less frequently. This results in more engine horsepower going directly to the drive wheels.