Importance of Fuel Delivery Systems


Oct 24, 2012
Fuel delivery is an important system in automobiles. Modern fuel delivery systems are designed depending on the type of fuel used and the performance required by the automobile. A fuel delivery system also ensures the cleanliness of the fuel. All engines require a method to store and deliver fuel to the engine. A fuel delivery system does this in an automobile. The main purpose of fuel delivery system is to supply the fuel and run the engine. Importance of fuel delivery systems Fuel pump relays: Producing adequate volume and pressure is the bottom line for fuel pump performance. A fuel pump relay is an electric switch that is directed on or off by the power train control module (PCM). When the ignition key is turned on initially for a period of three seconds in order to pressurize the system, and the next time the key goes to start, the PCM helps to activate the fuel pump relay again. Once the engine starts, the PCM gets signals from the crankshaft sensors to either turn off the pump or keep it running. Modern vehicles have an inertia switch to turn off the pump in the event of any accident. Anti-theft devices helps to deactivate the fuel pump in case if it detects tampering. Pulse modulated fuel pumps: These systems help to eliminate the need of a fuel pressure regulator by controlling the pump speed to change the fuel pressure. In pulse modulated systems, the PCM uses a pressure sensor that is mounted on the fuel line to monitor the fuel pressure. These systems also requires a scan tools to monitor the diagnostic trouble codes and to test the system by directing the fuel pump to produce different pulse rates. Modern filters and regulators in fuel delivery system
* Filters
* Fuel pumps are protected by a fuel strainer which is attached at the fuel inlet. Similarly, the fuel injectors are safeguarded by the fuel filters attached to the inlet of fuel and downstream at the fuel pump.
* In case if the fuel delivery system malfunctions, the first sign may be traced out at the fuel filters.
* In modern automobiles the fuel filters are placed inside the fuel tank at the inlet side of the fuel pump. * Regulators
* The pressure regulators ensure optimum fuel delivery by controlling pressure of the fuel pump.
* The pressure regulators are of two types.
* Dual-line systems
* The Dual-line system returns excess amount of fuel using a second line.
* Single-line Systems
* Single-line fuel injection system has a fuel pressure regulator and it depends on the PCM to maintain fuel levels. Fuel delivery system diagnosis
* Auto manufacturers are installing a sophisticated diagnostic system in to their PCM’s in order to help the mechanics to quickly diagnose the fuel systems.
* The PCM monitors the fuel delivery system performance by monitoring the oxygen sensor voltage.
* The PCM holds the fuel injectors open for a longer time to maintain correct oxygen sensor voltage, when the fuel pressure is low or if a vacuum leak develops.
* Modern automobiles are more about on board electronics. The diagnostic system contains rich and lean commands when the ratio of air fuel mixture is not appropriate. Fuel delivery systems are constantly updated in order to have good efficiency in the vehicles. Airtex Fuel Delivery Systems is the leading aftermarket supplier of mechanical and electric fuel pumps and modular reservoir assemblies (MRA). For over 50 years, the Airtex brand has been the benchmark of fuel delivery and cooling system components. Airtex fuel pump is an OE replacement pump. Airtex electric fuel pump and mechanical pump models are available for old and new cars.