What guideline must be followed regarding engine speed in order to drive efficiently?

Question

DentroTest · Accepted Answer

In heavy vehicles such as buses, the rev counter has a clearly marked green zone that indicates the optimal operating range of the engine, where the greatest torque is obtained with the lowest specific fuel consumption. To apply efficient driving techniques, when shifting up the change must be anticipated so that, after the revs drop because of the gear change, the needle ends up at the beginning of that green zone. In this way the engine keeps pulling strongly and with maximum economy. The red zone represents a dangerous over-revving that drastically increases consumption and can damage the mechanics, while dropping to the end of the green zone would indicate that the previous gear had been stretched excessively and unnecessarily.

What guideline must be followed regarding engine speed in order to drive efficiently?

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