Fuel management for commercial vehicles

Fuel management in commercial vehicles mainly refers to filtration and water disposal. The trend toward a so-called world engine—an engine platform for use in every region on earth—gives rise to considerable technical challenges. Depending on the region, this concept is confronted with different biofuel content and fuel quality levels. It is therefore necessary to facilitate optimal fuel treatment in all conditions.

Systems for fuel management

Fuel filters

Fuel filter modules for commercial vehicles efficiently prepare diesel fuels for the combustion process. For this purpose, they use high-separation filter media and feature an advanced functionality scope. For diesel engines, the functional range of the MAHLE fuel filter modules can be rather complex. The fuel can be cooled or heated, for example, or the water content of the fuel can be separated.

Water separation systems

In order to comply with demanding emissions limits, modern diesel engines typically employ common rail injection systems. These are extremely sensitive to solid particles and diesel fuel containing unsolved water. Since world engines are also used in countries with poor fuel quality and varying shares of biofuel, it is necessary to enable optimal separation of contaminants and water even under these conditions.

For this purpose, MAHLE has developed a solution with the active prefilter module that achieves a separation level of up to 98 percent in new condition.

Electrical heaters for fuel systems

MAHLE electrical heaters are used in diesel and ethanol engines for cold starting and operation at low ambient temperatures. For diesel engines, they ensure that flowability is maintained and prevent flocculation of fuel components that could lead to clogging of the filter. In ethanol engines, MAHLE heaters significantly improve the critical cold start.

When designing the heaters, MAHLE drew upon the company’s broad knowledge base in the area of fuel systems, thus achieving a high level of integration in the fuel filter module. Other salient features of the heaters include low pressure loss during high heat transfer to the medium, a robust design with separate chambers for the electronics and heating element, a low energy requirement, and a high power output (600 W). The heater is controlled by the integrated electronics or the engine management system. The heating element is based on modern resistance technology with a positive temperature coefficient (PTC), and the integrated overheating protection ensures maximum safety. With its modular design, MAHLE’s electric heaters can be flexibly adapted to the specific requirements of passenger car and commercial vehicle manufacturers.

MAHLE water level sensors

MAHLE water level sensors for fuel filter modules determine whether too much fluid has collected in the module during operation, thus ensuring reliable filter operation throughout the vehicle’s service life. With MAHLE’s innovative, patented technology, the sensor elements are made of conductive plastic instead of metal, preventing electrolysis problems from occurring. This, combined with a gasket concept based on two-component injection molding, adds to the robustness of the design.

Their broad 9–36 V operating voltage range makes the sensors suitable for a broad array of applications in passenger cars and commercial vehicles. Thanks to MAHLE’s extensive expertise in fuel filter systems, it was possible to achieve a high level of systems integration in developing the sensors. Yet the sensor platform can still be tailored flexibly to the requirements of different passenger car and commercial vehicle applications through adaptations in sensor element length and connection contacts, for example. Available in analog or digital format, the electronic sensor control system offers numerous add-on functions such as diagnostic options.