Fuel management for passenger cars

A central aspect of fuel management is the efficient filtration of the fuel, in order to protect the engine and its components from contamination and damage. As manufacturers increasingly pursue a strategy of identical parts or modular design, the same engine is being used in more and more regions of the world. The fuel quality varies accordingly, at times due to biocomponents in the fuel. The water content plays a role along with dirt particles. Water separation systems can pave the way for the global application of an engine while making it possible to use biodiesel.

The MAHLE product range for fuel management includes products such as fuel filters, water separation systems, fuel heaters, and activated carbon canisters.

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.

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.

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.

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.