Electric fuel pump is used in modern internal combustion engines to contribute fuel from the fuel tank to the injectors. The pump should deliver fuel under high pressure, so that the nozzle can spray it into the engine. For the proper machine carrying out fuel pressure should be within allowed specifications for a given engine. Too low-pressure can lead to "fuel starvation" machine misfire, excessive vibration or stop the machine under load. Too much pressure causes uneven machine running too rich mixture, and excessive pollution.
Electric fuel pumps are normally installed in fuel tank (intake), although some can be installed outside. Some cars may be adequate with two pumps (one pump inside the tank and the main pump on the outside). The location of the pump in the fuel tank helps mute the buzzing noise of pump's galvanic motor. Submersion into the fuel helps lubricate and cool the pump's engine. Driving with fuel tank filled with less than ¼ of its volume can shorten the life of the pump and cause rapid overheating. It also increases risk of pump left without of gas during rapid acceleration or deceleration.
Water Pressure Sensors
The pump is normally part of a module that also includes a float that carries electrical signals to the level indicator, placed on the dashboard. If the fuel pump needs replacing, it can be substituted separately or the faultless module assembly (it is expensive, but much easier).
Different galvanic fuel pumps have different designs. Some older designs used to use forced displacement of the circulation pump chamber. This type of pump can furnish very high pressure and constant flow. But at the outlet of the fuel pump has been strong pressure fluctuations, so often in the gas line after the pump was installed damper to sacrifice the amplitude of pulsation of gas pressure. Circulating accommodation can also be installed surface the tank and used with the second low-pressure pump installed in the fuel tank.
There is someone else type of fuel pump - "rotor-type". This organize is similar to organize of the oil pump and uses the offset rotor to push the fuel straight through the pump. someone else difference of the roller pump - "vane-type". The blades are used instead of rollers to push the gas straight through the pump. Most modern cars use a pump turbine. Blades of the impeller push gas straight through the pump. Turbine type pumps do not furnish the pressure fluctuations these types are less complex to organize and more reliable in operation. It is potential to replace a fuel pump by not former unit. In this case fuel pump's output should be within former specifications and as consumption the same as the former one. Use of an improper specs can cause deterioration of carrying out of the car.
How does galvanic fuel pump work?
When the ignition, the electronic control unit excites the relay, which supplies voltage to fuel pump, its motor starts to rotate, and within a few seconds it creates requisite gas pressure. Fuel feeds into the inlet pump straight through a mesh filter to delay the rust and dirt. Outlet of the pump the gas passes straight through the check valve, singular acting (valve maintains a residual pressure in the system, when pump does not work) and feeds to the machine straight through the fuel line and filter. The fuel filter catches any rust, dirt and other solid contaminants that have passed straight through the pump to prevent the penetration of these particles in the injectors.
Further, the gas enters the fuel rail, placed on the machine and from the rail to each injector. Fuel pressure regulator, placed on the ramp, maintains the fuel pressure and throws any excess back to the tank. Start the machine and the galvanic fuel pump starts to control continuously and to keep pumping gas until the machine is running. If the machine stops, then the electronic control unit receives a signal from the sensor and the crankshaft Ecu will turn off the pump.
A lot of cars (especially Fords) have an inertial accident switch which disables the fuel pump in the event of an accident. It is envisaged to sacrifice the risk of fire when the fuel line is damaged. To return the accident transmitter to its former state - press the reset button on the sensor. On older cars pumps operated at a constant speed. In newer designs pump's speed is being controlled by the electronic control unit in order to legitimately match allowed specifications.
Fuel pump failure
The fuel pump can fail for any reasons: - Due to the presence of contaminants inside the fuel tank (dirt or rust); - When driving out of gas; - As a supervene of overheating (in constant request for retrial with a low level of gas in tank); - Low voltage (problems with electrical wiring); - As a supervene of overloading (for a clogged fuel filter excessive resistance of the filter element can cause an overload of galvanic motor pump). The harder the conditions of the fuel pump, the more power is required for its operation. Electric fuel pump often fails without any warning. You may drive your car without a trouble, and within a small the pump fails, the machine just stalls and the car gets up in the middle of the road. Or in the morning you are going to start the car but the machine just will not start.
By what signs can one predict the damage the fuel pump? One way is to listen to the noise of the pump when the ignition is on. faultless absence of noise indicates that it is not working. It can be caused by a malfunction of the pump, pump relay malfunction, the fuse or the lack of voltage. On most cars when fuel pump fails you wouldn't see usual Check machine light on. Most modern engines adequate with the union to check the fuel pressure on the ramp nozzles. Connecting fuel pressure gauge to the fitting check valve will quickly show either the pump produces pressure or not. On engines without pressure test union, to portion pressure can be done by connecting directly to the fuel line at the junction of the ramp. If the gauge indicates zero - the pump does not work. If the pressure is less than nominal, it will be requisite to carry out added analysis to identify the causes of low fuel pressure.
galvanic Fuel Pumps - Design, Work and FaultsAbsolute Pressure Sensors Piezoelectric Pressure Sensors Optical Encoder