GreenCars 101

How Fuel-Efficient Gas Vehicles Work

Dave Nichols
Jul 2023
How do automakers create ever more fuel-efficient vehicles? There are a number of technologies that have helped gasoline engines continue to become more efficient. How do they work? Let’s find out.
Engine Of Fuel-Efficient Vehicle

Fuel Economy vs Fuel Efficiency

As gasoline prices continue to climb, everyone is interested in increasing fuel economy and making their car more fuel efficient. The Environmental Protection Agency (EPA) has set ratings on all makes and models of cars sold in America to let consumers know how many miles they can expect to get per gallon of fuel. But there’s more to fuel economy than meets the eye.

For instance, a vehicle’s fuel-efficiency can be reduced by a number of causes such as wind resistance, tire drag, engine malfunctions, a faulty fuel pump and more. Naturally, how you drive has a big effect on how many miles per gallon you get as well. Heavy acceleration wastes fuel. Using cruise control when driving on the highway reduces the consumption of fuel.

But how do automakers create ever more fuel-efficient vehicles and how do they work? Let’s find out.

Woman putting groceries in car trunk while car charges

Modern Fuel-Efficient Cars

As automobiles have evolved, they have gotten better and better. Today’s vehicles have better suspension, smarter fuel-efficient drivetrains, and advanced technology that borders on autonomous travel. They are made from advanced materials, have aerodynamic designs, are lighter, and have highly efficient engines and transmissions. Put all that together and modern vehicles have achieved gains of over 40 percent in reliability and fuel efficiency in the last ten years. Simple vehicle maintenance also improves fuel economy. You will get more miles to the gallon if you change your oil and oil filter as recommended by the manufacturer, and make sure your tires are always inflated properly.

Interestingly, one of the biggest contributors to wasted gas is when your car is sitting and idling. Idling for long periods is like throwing fuel away and you are also polluting the air for no reason.

blue electric car

New Fuel-Efficient Technology

The following new technologies all aid in better fuel efficiency and engine performance.

Cylinder Deactivation: Many modern cars and trucks that have a V6 or V8 engine have the ability to reduce the number of active cylinders while cruising. A V8, for instance, might become a V6 while cruising on the highway and only activate all cylinders under acceleration to save fuel.

Direct Fuel Injection: Gasoline is injected directly into the cylinder barrel for more efficient combustion than when air and fuel are mixed outside the cylinder.

Continuously Variable Transmission: Many new cars have this feature in which a pair of variable diameter pulleys that are linked by a belt or chain, create a multitude of gear ratios. By doing so, it limits the revolutions per mile, thus reducing fuel consumption.

Integrated Starter/Generator: This freaked me out the first time I drove a car with an integrated starter. The engine shuts off when you stop for any period of time (like at a stop light). The engine starts up when you touch the accelerator, reducing idling time.

Turbochargers and Superchargers: These systems force compressed air directly into the cylinders and that makes the fuel burn completely and efficiently at every piston stroke, adding performance while using less fuel.

Variable Valve Timing and Lift: Special valves control the air and fuel mixture as it enters the engine and controls the spent exhaust mixture as it exits the cylinders. This very exact timing reduces wasted fuel during detonation.

Front view of a Tesla Model 3 driving through canyon roads

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