Factors That Affect Fuel Efficiency

Fuel efficiency measures how far a vehicle can travel on a gallon of gasoline. Fuel efficiency is especially important when gas prices are high.


Several factors affect fuel economy. Regular maintenance is key. Plan your errands to avoid multiple stops and to allow the engine to cool down between trips.

1. Aerodynamics

The science of aerodynamics focuses on the movement of air and other gaseous fluids. This knowledge has led to a number of engineering applications including car design, wind tunnel testing and the construction of tall buildings and bridges.

Any object that moves through air reacts to the laws of aerodynamics. From a rocket blasting off the pad to a kite in the sky, everything that goes through air is affected by the four forces of flight: lift, weight, thrust and drag (NASA, 2009 1). 인천운전연수

Vehicles use engine power to overcome aerodynamic resistance, or drag, which increases as speed increases. This is why carmakers focus on lowering the frontal area and minimizing mechanical resistance as they design cars, SUVs, pickups and trucks for fuel efficiency. The frontal area of a vehicle, its speed and the density of the air determine how much engine power is needed to overcome aerodynamic drag. The drag force is proportional to the square of the vehicle’s speed, so a small change in speed can require an enormous amount of engine power.

2. Weight

Weight plays a significant role in fuel efficiency, as the more mass or weight that the vehicle has to move, the more energy it requires. This energy comes from the vehicle’s engine, which uses fuel to power it and keep it moving. 인천운전연수

A vehicle’s fuel efficiency e depends on its weight and other factors, including engine power and drivetrain. The most direct way to determine the effect of increased vehicle weight on fuel economy is to perform a test. However, this method may be difficult to carry out in real life due to the need for similar driving conditions over a long distance to achieve meaningful results.

Alternatively, you can use your vehicle’s owner’s manual or in-car maintenance reminder to find out the recommended maximum load. You can also reduce fuel consumption by avoiding unnecessary cargo. Remember, even removing an extra 100 pounds can reduce your fuel economy by about 1%. Always remove any unnecessary items from the vehicle when not in use and make sure that the cargo is properly secured. Use only the gasoline grade specified by the vehicle manufacturer and choose low-sulfur diesel or Top Tier gasoline for best performance.

3. Transmission

A transmission is a metal case that houses a series of gears — hence the name “gear box.” Its role is to convert torque and speed output from the engine to another system in your vehicle. Often, it’s the transmission that is responsible for limiting the amount of power a motor vehicle consumes in order to achieve optimal fuel efficiency.

In this new video from YouTube channel Engineering Explained, Jason Fenske discusses the role of the transmission in achieving fuel efficiency. He explains how to get the most efficient mileage from a manual transmission car by keeping RPM low.

However, he also talks about how automatic and AMT transmissions can lower fuel efficiency by taking control out of the driver’s hands. This is because AMTs and automatic transmissions typically shift at higher RPMs than a manual transmission. Consequently, they may cause the engine to use more fuel than necessary. This can be a serious concern when you are considering buying an AMT or automatic transmission. Especially because AMTs and automatic transmissions typically have more moving parts than a manual transmission.

4. Fuel system

The fuel system is the part of your vehicle that transfers gasoline or diesel to the engine for combustion. It includes the fuel tank, fuel pump, fuel line, fuel filter and fuel injectors. Fuel systems must work properly for your vehicle to achieve optimal fuel efficiency.

In some cases, your car’s fuel system may need to be cleaned for better performance. Fuel systems should be cleaned regularly to reduce the risk of contamination, which can result in poor performance and engine damage.

A vehicle’s fuel economy is the distance travelled per unit volume of fuel consumed. It is measured in miles per gallon (MPG) in the United States, but is also commonly used in Europe, India, Japan, South Korea and Latin America with the metric unit km/L. However, this metric is flawed because it causes consumers to underestimate the impact of small increases in efficiency, which are disproportionately associated with changes in weight. A better metric is fuel consumption, which provides a more accurate picture of a vehicle’s performance. This is because it measures energy consumption over a driving schedule, including the time spent idling and braking.

5. Tires

While it may seem unlikely that tires have a significant impact on fuel efficiency, they do. Tires have a unique interaction with the road that can significantly affect handling, braking and acceleration, which impacts your vehicle’s fuel efficiency.

The most important factor for fuel economy is rolling resistance, the amount of force required to get a tire moving from a stopped position. This is caused by the tire deforming and recovering, a cycle that consumes energy. Tires with low rolling resistance use less force to move, resulting in lower fuel consumption.

Tire width and tread pattern also impact fuel efficiency. Smaller tires have a smaller circumference and require less force to get moving, while larger tires require more power. The best tires for optimal fuel efficiency are those recommended by your vehicle manufacturer in your owner’s manual.

Maintaining proper tire pressure is another simple but effective way to improve fuel efficiency. Tires that are underinflated have much higher rolling resistance, requiring more energy to move them.