How efficient are conventional internal combustion engine vehicles

Most of the vehicles we drive today are powered by internal combustion engines. These engines produce power by burning fuel with air in the engine cylinder, which when it is ignited, generates energy used to push the piston downward and ultimately to propel the vehicle forward.

Sounds logical except internal combustion engines aren’t able to convert all of the chemical energy in the fuel into forward motion; in fact, only about onequarter of the energy in the fuel reaches the wheels to propel your vehicle. The rest of the energy is lost primarily as heat through the engines cooling system and exhaust and smaller amounts of energy are lost through engine friction, pumping the air into and out of the engine, combustion inefficiencies, drivetrain losses and parasitic losses.

Curious about where all that energy is going?

• Engine losses – about 66 percent. Losses happen as a result of engine friction, pumping air into and out of the engine and wasted heat, which is the largest element of engine energy losses.

• Drivetrain losses – about 5 percent. The drivetrain transfers energy from the engine to the wheels through several components such as a driveshaft, transmission, differential and axle. Friction in the gears and bearings causes energy losses to occur.

• Parasitic losses – about 4 percent. Things like the water pump and alternator draw power from the engine.

Operating your vehicle at peak efficiency is part science and part common sense. The bottom line is that vehicles today are more fuel-efficient than ever before but how we drive them affects the money we pay at the pumps. Check out the Natural Resources Canada website at www.vehicles.nrcan.gc.ca for some fuel-efficient driving tips. News Canada