Chapter 3: Preventing Energy Losses that Drain your Vehicle of Power and Increase Fuel Consumption

Types of Losses

Energy management is the key to fuel efficiency. Prevent your vehicle from losing too much of the energy produced by your engine to friction and other forces, and you have made a big step in creating a more fuel efficient vehicle.

There are inherent and ever-present forces always draining energy from your vehicle. The three basic types of losses are as follows:

Friction - wind resistance, rolling resistance, mechanical friction (two parts moving against each other), and hydraulic friction (force required to push or pump a liquid)

Mechanical Load - the combination of losses incurred by the engine due to powering accessories such as air conditioning, electrical, and power steering as well as vehicle weight and payload

Heat & Noise - loss of energy in the form of heat loss or vibrational noise

Reducing any of these energy draining forces will allow more of the energy produced by the engine to be transferred directly to turn the wheels and propel your vehicle more efficiently.

An increased level of any of these draining forces adds to the burden your engine must carry as it attempts to power your vehicle. For example, a heavier payload causes the engine to work harder under load, just as tires with low pressure create extra resistance and make the engine work harder.

This section will address each of these types of losses and offer recommendations for reducing or even eliminating some sources of the ever-present losses that drain energy from your vehicle.

Reducing Friction Losses

Wind and Rolling Resistance

Aerodynamics plays a very important part in the efficiency and fuel economy of your vehicle. You have noticed that sports cars are sleek and streamlined, and for a reason. The cars shape is more finely tuned to allow air to pass more cleanly over these vehicles with a minimal amount of turbulence.

The smoother and better managed the air flow over a surface, the less turbulence is formed, and the less air resistance or friction that needs to be constantly overcome.
Larger vehicles are made with another purpose in mind other than for low wind resistance. Many trucks and vans are box-like in shape to accommodate cargo and big engines. The same goes for SUVs which are generally designed to carry many passengers and large-volumes of cargo as well.

These vehicles are not very aerodynamic and as a result tend to have bigger engines and more horsepower to overcome the increased air resistance. In fact, engineers will tell you the drag or wind resistance of a vehicle is proportional to the square of the speed. In other words, if you double your speed, you quadruple the aerodynamic drag you must overcome - thats four times more resistance!!

And heres the kicker - the power needed to overcome that drag increases proportionally to the cube of the speed. So, if you double your vehicle speed, you need eight times the horsepower to overcome four times the drag.

Heres another example. If you increase your speed from 40 to 60 miles per hour, thats 1.5 times faster. You get 2.25 times more resistance (1.5 x 1.5 = 2.25). Your engine needs to come up with 3.4 times the horsepower (1.5 x 1.5 x 1.5) to keep the vehicle moving along at 60 than it did at 40 miles per hour.

You now start to get a feeling for why trucks and SUVs require such big engines, and why mileage experts tell you to drive slower to conserve fuel.

Rolling resistance is exactly what it sounds like. It is the resistance of the rubber tires rolling over the road surface, combined with the friction of the brakes and wheel bearings.

Amazingly, one third of the total energy output of the engine is consumed by rolling resistance. Other factors playing into rolling resistance are the pressure, quality and type of tires, your alignment and the weight of your vehicle.

New radial tires have the best of both worlds with a comfortable ride as well as much lower rolling resistance than the older bias ply tires - almost double the efficiency!

Taller and fatter tires obviously offer higher wind resistance than smaller and narrower tires. A lighter vehicle presses down on the tires less and reduces road friction.

Tire pressure is the single largest factor you can immediately control. When temperatures drop, the pressure in your tires decreases. For every 10 degrees reduction in outside temperature, cold tire pressure is estimated to drop one pound per square inch (PSI).

According to Goodyear Tire Company, "Running a tire 20 percent under inflated - only 5 to 7 pounds per square inch - can increase fuel consumption by 10 percent. That can easily cost motorists two or three miles per gallon. Not only that, but the tires tread life is reduced by 15 percent".

Mechanical Friction

Rubbing parts are the source of mechanical friction. Any time two moving parts move against one another as in the case of engine crank-shafts, connecting rods, camshafts, valves, bearings, gears, belts, and brakes, there is friction, heat loss, and resulting losses as energy is created in the vehicles engine combustion chambers and transferred from each cylinder through the engine, drive-train, tires, and to the ground.

There is a tremendous amount of research looking into creating frictionless machines, bearings and lubricants. Modern technology has made some major advances and has produced a number of materials and lubricants that greatly reduce the amount of friction encountered in a vehicle. We are seeing Teflon coatings and synthetic bearing grease, among other products, available today.

Wear and tear is a natural by-product of mechanical friction. Gears wear out, belts crack and break, bearings wear thin and brake pads wear out, all because of friction.

We will show you some alternative methods of applying high tech lubricants in your vehicle and perform other adjustments to greatly reduce friction and enhance fuel efficiency.