Usually, fuel pumps are powered using electrical power from the car battery; that is why there must be a relay which controls the on/off process. This relay, commonly situated in the engine bay, triggers the Gas Pump when you turn on your ignition. In almost all cars the pump runs at about 12 volts and many new vehicle also have extra electronic control modules (ECMs) in place to help regulate performance of pumps. This adjustment of voltage by the ECM(s) allows more variation to the amount of fuel put in per stroke.
Tradtional fuel pumps were simply electrical connections, but modern fuel systems today use variable voltage control which can improve mpg by 10% to 15%, during light load. This ensures that only the required amount of fuel reaches the engine by adjusting power to pump, at idle or slow run conditions. Many hybrid and electric vehicles, for example, include fuel pumps controlled by manufacturers through an ECM to save energy — underscoring the automotive industry trend toward more efficient options.
Earlier cars, especially those equipped with carburetors came standard mechanical fuel pumps – it relied on the movement generated by the engine’s camshaft or crankshaft. The first is a positive displacement-type pump (bottom image) that uses one of several known mechanical diaphragms to suck fuel from the tank. However, they are mostly obsolete on today’s vehicles as higher-pressure-capable electrical pumps have been the industry standard for years. Fabrizio Bozzetti, Vice President of Aftermarket at UCI-FRAM® AutoBrasil says “industry reports that up to 95% of the vehicles manufactured today are equipped with electric fuel pumps which offer durability and consistent fuel pressure across engine operating speeds”.
Newer fuel pump technology like those with brushless motors can withstand higher voltages and are proven to be as much as 30 times longer lasting than the conventional carrie types. Brushless designs minimize moving parts so there is a lower friction and no chance to generate heat; therefore, the pump has better energy efficiency and requires less maintenance. The brushless fuel pumps have a potential lifespan of 150,000 miles that exceeds the lifespans of any conventional electric pump by nearly half.
Or as Tesla CEO, Elon Musk once put it “Simplicity and efficiency go hand in engineering.” We see this principle applied to the changing face of fuel pumps, as a more efficient design will save you energy and also reduce wear on the component over time. Fuel Pump in current cars, on the other hand have become crucial to performance and fuel economy as they modulate power through electronic systems that dial back or hike up output based on what an engine requires at any given moment.