Their are several factors that determine the overall fuel economy of a vehicle.
- The weight of the vehicle.
- Aerodynamic drag on the vehicle.
- Rolling resistance.
- Overall efficiency of the drive train.
- And the manner in which the vehicle is driven.
- Environment the vehicle is driven in.
The weight of the vehicle does affect fuel economy. The reason is that it takes more energy to accelerate to speed because of increased mass. This also causes of increased tire rolling resistance.
Aerodynamic drag of the vehicle. What determine the aerodynamic drag on vehicle are its shape, size, and speed it is traveling at. The faster the vehicle is traveling the more the drag. This is one of the reasons that a car will get better mileage than a SUV. The car has a more slippery shape. A SUV is taller and has more frontal area, and has a poor aerodynamic shape. This is more evident the faster the vehicle is traveling.
Note: Pickup trucks should travel with its gate up. With the gate up it traps an air bubble behind the cab of the truck thus reducing drag. This was proven on the TV show "Myth Busters".
Rolling resistance is amount energy it takes to move the vehicle. A heavier vehicle requires more energy make it roll down the road.
Overall efficiency of the drive train this is how efficient the burning energy of the fuel goes to the rear axle. This deals with how efficient the engine is and the losses in the rest of the drive train. Thing is does the engine run at efficient level during most driving conditions?
The manner in which the vehicle is driven does have a significant impact in your MPG (Miles per Gallon) Avoiding jack rabbit starts. Try not to tail gate. The reason is that when you tail gate you constantly are going back and forth between the gas and the brake. Also look for opportunities to cost more before having to stop. This reduces the amount of time your on the gas. Plus the light may change before you need to come to a complete stop.
Environment the vehicle is driven in . Cold weather will reduce fuel economy. Also hilly roads will decrease fuel economy. And stop and go traffic will also hurt your mileage.
So when it comes time to select a new vehicle take your needs and mileage into consideration.
Check list to better fuel economy .
- Keep tires inflated to proper pressure. This one item is one of the most neglected.
- Do not speed. Fuel economy drops rapidly at speeds over 65 mph.
- Avoid brisk acceleration.
- Watch the flow traffic so you can avoid unnecessary braking.
- Try to coast to a stop earlier instead breaking right before the stop.
- If you time your approach to the stop light so you may not need to stop.
- Allow a greater distance between you and the car in front of you. So that you don't have to step on the brakes so quickly. The goal is to make your driving more fluid.
- Change the oil on a regular basis, but don't over fill.
- Remove any unnecessary cargo to reduce vehicle weight.
Tire pressure . The tire pressure for most vehicles can be found on the driver’s door end, or door jam. The maximum tire pressure can be found on the side of the tire. This tire pressure should never be exceeded. Exceeding the tire manufactures pressure could result in tire failure. The vehicle manufacture has determined that the tire pressure as marked on drives side door is best al round pressure. This pressure provides the best ride comfort, stability, traction and fuel economy. Raising tire pressure will lower the rolling resistance can increase your MPG. But when you raise the tires pressure it does reduce ride comfort, and also reduces the tire patch. The tire patch is the tire surface that is in contact with the road surface. This can reduce traction and vehicle stability. This will be more evident snow and rain. Drivers who raise tire pressure do it at their own risk.
Low rolling resistance tires are engineered so the tire rolls more easily. This is done be changing the tires side wall and tread construction. Silica is added to the rubber compound in order to alter its properties. Switching to a low rolling resistance tire can improve fuel economy from about 2 to 7%. High performance tires found sports cars usually have high rolling resistance. Such as the Michelin MXV tires that have a low rolling resistance.
Reducing Aerodynamic drag. This can be done be removing bug or wind deflectors that were added to the exterior of the vehicle. Luggage racks should also be removed. Mud flaps that hang out past the edge of the tires will produce some air drag