A Comparison Between Electric and Hybrid Vehicle Fuel Pumps

If you're not familiar with fuel pump design, it's easy to look at this topic and scratch your head. Electric vehicles don't have fuel pumps.

You're right, but there are electric fuel pumps and mechanical ones, and some recent design innovations have led to the creation of performance pump designs that do not fit either category easily.

Efficiency & Energy Consumption

Electric fuel pumps became the most common choices for automakers as EFI became the standard for new cars, and the two happening together was not a coincidence. Mechanical pumps are generally designed for carbureted vehicles and not fuel injected ones, and many of the industry's innovations during the pivot to fuel injection led to new insights about fuel use and safety.

Electric fuel pumps like the OEM Infiniti G35 fuel pump can be placed inside the gas tank, completely submerged. Since liquid fuel does not ignite, this reduces the risk of fire related to the fuel pump. Electric pumps also provide a consistent fuel pressure and constant flow to the engine, rather than a cyclical one, so gas is never held near the engine heat for a protracted time.

Fuel efficiency is also increased when fuel is above a certain pressure threshold, and the ability of electric pumps to provide that pressure and hold it consistently led to gains in vehicle fuel efficiency across most vehicle classes. For those reasons, it is easy to believe that electric pump motors are simply better. They are better than old mechanical designs, but they have the tradeoff that all electric motors have, and that is the performance cost.

Energy consumptions goes through the roof when you place a high demand on an electric motor, and eventually performance part designers looked to a combination of electric and mechanical design factors to create next-generation aftermarket fuel pumps that don't require you to upgrade a Toyota Camry alternator to accommodate their electrical draw.

Looking Into the Future

Performance fuel pump designs moved to an energy-efficient combination of a belt-driven engine-mounted pump that uses a portion of the engine's mechanical energy and an internal electric engine in the tank that feeds the fuel from the tank into the high-pressure line driven by the mechanical pump. This hybrid system uses two motors, rather than a single hybrid mechanical/electric motor, and as a result neither has to do all the work.

Not all of these pumps are aftermarket options, either. The benefits of the hybrid design have led to their adoption by some automakers, and it is likely there is another design revolution underway as gains in fuel economy that preserve engine power become more important to consumers.

Preparing To Install an Electric Fuel Pump

Whether your fuel delivery system uses an electric pump or a hybrid design, there's still an electric motor in the tank. When it's time to replace that part, you'll need to consult vehicle wiring diagrams to understand exactly how to connect the replacement and how much power it will draw, especially if you are going up a performance tier. Start your research today so you know if you also need an alternator upgrade before you order your new pump.