Stall (engine)

For the effects of a stall of the airfoil within the compressor of a jet engine, see Compressor stall.

A stall is the slowing or stopping of a process and in the case of an engine refers to a sudden stopping of the engine turning,<ref name=schultz>Schultz, Mort (March 1979), "How to stop stalling", Popular Mechanics, pp. 128–130, ISSN 0032-4558, OCLC 3643271, retrieved 13 November 2014</ref> usually brought about accidentally.

It is commonly applied to the phenomenon whereby an engine abruptly ceases operating and stops turning. It might be due to not getting enough air, energy, fuel, or electric spark, fuel starvation, a mechanical failure, or in response to a sudden increase in engine load.<ref name=schultz/><ref>Hillier, Victor A. W. (1990), Fundamentals of Motor Vehicle Technology (4th ed.), Cheltenham: Nelson Thornes, p. 223, ISBN 9780748705313, OCLC 46761850, retrieved 13 November 2014</ref> This increase in engine load is common in vehicles with a manual transmission when the clutch is released too suddenly.<ref name=wardlaw>Wardlaw, Christian (11 August 2014), "Get the most out of your car: How to drive a manual transmission", Daily News, New York, archived from the original on 13 August 2014, retrieved 14 November 2014</ref>

The ways in which a car can stall are usually down to the driver, especially with a manual transmission. For instance, if a driver takes their foot off the clutch too quickly while stationary then the car will stall; taking the foot off the clutch slowly will stop this from happening. Stalling also happens when the driver forgets to depress the clutch and/or change to neutral while coming to a stop.<ref name=wardlaw/> Stalling can be dangerous, especially in heavy traffic.<ref name=schultz/>

A car fitted with an automatic transmission could also have its engine stalled when the vehicle is travelling in the opposite direction to the selected gear.<ref>Roth, Dan (20 August 2009), "What Would Happen If You Put Your Car In Reverse While Driving?", AOL, archived from the original on 26 August 2009, retrieved 14 November 2014</ref> For example, if the selector is in the 'D' position and the car is moving backwards, (on a steep enough hill to overcome the torque from the torque converter) the engine will stall, due to the fact that the engine is forced to turn in the opposite direction to what it is actually doing. This is because, hypothetically, if the car is rolling backward fast enough, the force from the rotating wheels will be transmitted backward through the transmission and act as a sudden load on the engine.

Digital electronics fuel injection and ECU ignition systems have greatly reduced stalling in modern engines.<ref>Hatch, Steve V. (2012), Computerized engine controls (9th ed.), Clifton Park: Delmar, Cengage Learning, p. 529, ISBN 9781111134907, OCLC 676729348, retrieved 13 November 2014</ref>

See also

• Stall torque