Fuel management for passenger cars

One of the most important tasks of fuel management is to effectively remove dirt particles and water from the fuel, in order to protect the engine and its components from damage and contamination.

Systems for fuel management

Fuel filters

Fuel filter modules efficiently prepare gasoline and diesel fuels for the combustion process. For this purpose, they use high-separation filter media and feature an advanced functionality scope. The fuel pressure in gasoline filters can thus be adjusted by a pressure regulator integrated in the fuel filter.

For diesel engines, the functional range of the MAHLE fuel filter modules can be significantly more 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.

Activated carbon canisters

Every fuel tank has a pressure balance pipe, which ensures that no vacuum develops as the tank is emptied, and that heating and expansion of the fuel does not create overpressure in the tank. The fuel fumes that escape when the overpressure is relieved are fed through a pipe to the activated carbon canister, where they are captured or stored. The fuel fumes stored in the filter are then burned during engine operation. Activated carbon canister modules thus reliably reduce the emission of hydrocarbons and pollutants.

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.

Water level sensors

Water level sensors for fuel filter modules determine whether too much liquid are collected in the assembly during operation. With our new technology, the sensor elements are no longer made of metal but of conductive plastic, thereby preventing electrolysis problems. With operating voltages from 9 to 36 volts, the sensors are suitable for a broad range of applications.