TECH: TOPICS
Many owners assume driving their car slowly and gently is economical. It isn't. Put simply, when a car is being driven slowly, its engine is operating inefficiently and burns more fuel than it needs to. This is because where the engine is tuned to develop peak torque (ordinarily in the middle of the rev range) is where it extracts most energy from fuel — increased combustion pressure or torque is required to push the pistons down and rotate the crankshaft.
There isn't much you can do to influence fuel consumption when driving above mid-performance levels (where the engine is likely to be performing fairly efficiently) because revving higher and above sixty percent throttle not only increases engine internal losses, but rolling and air resistance begins to impact on loads. Besides, accelerating a mass fast will always be uneconomical.
That said, few people realise that to drive below these levels, such as when cruising at a constant low speed with relatively small throttle openings, is increasingly uneconomical. The engine expels greater emissions the slower you go. This is because are cars less efficient at slow speed?
