Consistent to its unprecedented tradition of automotive engineering achievements, Mercedes Benz continues to provide excellent performance parts that provide power to the engine and security to the proud owner. A key to understanding and appreciating the legacy of the original brand with the three-star is to study its cutting edge mechanism and engine system. Two of its generally crucial parts are the Mercedes alternator and fuel pump.
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Mercedes alternator is part of the Benz's charging system that produces electricity for may of its intricate devices. A type of generator, this alternator transforms mechanical energy into electrical energy. Although Benz's battery supplies some electricity, most of the electrical mechanisms within the vehicle, require the alternator's steady stream of power.
As a background information, alternating current (rather than direct current) gives the alternator its name, because this is the type of electricity it creates. It is mainly a mechanical device, concealing a set of pulleys, wheels, brushes and wires, which hooks to the crankshaft and runs to the battery. This way, the gasoline powers the engine to turn the crankshaft, which in turn connects to the alternator. The alternator converts that motion into current whenever the car is running. The resulting electricity operates the cooling fan, headlights, windshield wipers, radio, defogger, and air conditioning.
To be more specific, an alternator is generally very efficient at producing a constant, high voltage, even when the car is idle, because of how it works. The belt (from the crankshaft) connects to a pulley system, called the rotor, such that when the belt is turning, it moves magnets across a special surface, called a conductor. Moving magnets, in the stator, generate an electrostatic field, otherwise known as electricity. This alternating current is controlled by a voltage regulator to keep the voltage steady. Another part, called the diodes, convert alternating current into direct current that flows on to the battery and other components.
In view of an alternator's unpredictability in terms of malfunctioning, which could result to an engine stop, the Mercedes designed a unique gauge/sensor to monitor the vital signs of the Mercedes Benz alternator and other systems of the engine.
On the other hand,
Mercedes fuel pump are usually located inside the gas tank. This helps prevent vapor lock and keeps the fuel pump cool. The pump is a turbine type hydraulic unit directly coupled to a permanent magnet motor. Fuel is used as a lubricant and coolant for the motor. The reason electric fuel pumps are used in an electronically-fueled engine, such as in most Mercedes, is that they can produce the high pressures needed for proper fuel management. Typically an electric fuel pump is capable of putting out about 90 psi of fuel pressure. A check valve is incorporated in the fuel outlet to hold pressure when the pump is not running and a pressure limiter valve is located on the pressure side of the fuel pump housing with a return passage to the fuel inlet side to keep fuel pressure within specs.
When the rotor disc rotates, the rollers are pressed outwards by centrifugal force and act as a circulating seal. A pumping action is created by the circulating rollers that draw in fuel at the inlet port and force the fuel through the outlet port into the fuel system. When the pump is shut off, the check valve in the fuel outlet will close, therefore prohibiting the fuel from returning to the fuel tank via the fuel pump. The check valve will therefore maintain a pressure in the fuel lines called the "rest pressure."
The maximum fuel pump pressure (not fuel system pressure) is dependent on the calibration of the pressure limiter. If the fuel pump pressure exceeds a preset limit (for example a clogged fuel filter), the pressure limiter will open a by-pass to the fuel inlet side of the pump. The fuel pump is mounted along with the fuel tank sending unit and care must be taken when removing the pump/sender assembly so as not to damage the sender unit. Some vehicles have an access panel to get to the fuel pump without having to drop the tank, including Mercedes Benz and other Europerean cars.
No matter how sophisticated and cutting edge the engine design of a Mercedes, BMW, or a GM, their power and performance all goes back to the fundamentals – a reliable alternator and a sound fuel pump.
