Starting weakness

A start-up weakness in motor vehicles with an internal combustion engine usually occurs in vehicles with a high liter output and small cubic capacity .

The power graduation of the motor is then selected so that it delivers a high peak power at high speeds . As a result, performance at low engine speeds suffers inherent in the system, as the measures to increase performance at high engine speeds (large inlet cross-section , short inlet duct, large exhaust cross-section , low back pressure in the exhaust, more valves per cylinder, etc.) are not conducive to performance at low speeds.

Since the engine is naturally running at rather low speeds when starting, the engine has too little torque and only revs up unwillingly. This can have the consequence, for example, that the engine is “stalled” due to a lack of feeling in handling the clutch pedal . This is a problem for novice drivers in particular (especially with gasoline engines).

Some complex technical measures (e.g. VTEC , variable inlet geometry, variable outlet geometry) are used by the industry to counteract starting weaknesses by increasing the torque at low speeds without impairing the peak performance too much.

literature

• Hans-Hermann Braess, Ulrich Seiffert: Vieweg manual automotive technology. 2nd edition, Friedrich Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig / Wiesbaden, 2001, ISBN 3-528-13114-4