A stall is the slowing or stopping of a process, and, in the case of an
engine
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.
Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...
, refers to a sudden stopping of the engine turning,
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
An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...
,
energy
Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and l ...
,
fuel
A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...
, or
electric spark
An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an Ionization, ionized, Electric current, electrically conductive channel through a normally-insulating medium, often air or other ga ...
,
fuel starvation
In an internal combustion engine, fuel starvation is the failure of the fuel system to supply sufficient fuel to allow the engine to run properly, for example due to blockage, vapor lock, contamination by water, malfunction of the fuel pump or i ...
, a mechanical failure, or in response to a sudden increase in engine load.
[ This increase in engine load is common in vehicles with a ]manual transmission
A manual transmission (MT), also known as manual gearbox, standard transmission (in Canadian English, Canada, British English, the United Kingdom and American English, the United States), or stick shift (in the United States), is a multi-speed ...
when the clutch
A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...
is released too suddenly.[ Stalling can be dangerous, especially in heavy traffic.][
A car fitted with an ]automatic transmission
An automatic transmission (AT) or automatic gearbox is a multi-speed transmission (mechanics), transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions.
The 1904 ...
could also have its engine stalled when the vehicle is travelling in the opposite direction to the selected gear. 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
A torque converter is a device, usually implemented as a type of fluid coupling, that transfers rotating power from a prime mover, like an internal combustion engine, to a rotating driven load. In a vehicle with an automatic transmission, the ...
) the engine will stall, because 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 system
Ignition systems are used by heat engines to initiate combustion by igniting the fuel-air mixture. In a spark ignition versions of the internal combustion engine (such as petrol engines), the ignition system creates a spark to ignite the fuel-ai ...
s have greatly reduced stalling in modern engines.
Anti-stall systems
An anti-stall system is an automatically operated electronic clutch control device preventing the stalling of an engine by engaging the clutch when the ECU detects that the engine revs are too low. They are used in motorsports such as Formula One
Formula One (F1) is the highest class of worldwide racing for open-wheel single-seater formula Auto racing, racing cars sanctioned by the Fédération Internationale de l'Automobile (FIA). The FIA Formula One World Championship has been one ...
and Indy Car
IndyCar, LLC (stylized as INDYCAR), is an auto racing sanctioning body for American open-wheel car racing headquartered in Indianapolis, Indiana. The organization sanctions two racing series: the premier IndyCar Series with the Indianapolis 5 ...
, but not Formula 2
Formula Two (F2) is a type of open-wheel formula racing category first codified in 1948. It was replaced in 1985 by Formula 3000, but revived by the FIA from 2009 to 2012 in the form of the FIA Formula Two Championship. The name returned aga ...
and Formula 3
Formula Three (F3) is a third-tier class of open-wheel formula racing. The various championships held in Europe, Australia, South America and Asia form an important step for many prospective Formula One drivers.
History
Formula Three (adop ...
, and may be regarded as a driver aid since it usually keeps the engine running even if the car stops on track while in gear. It is also sometimes used on production cars.Ny Mercedes Vision
/ref>
See also
* Stall torque
* Dashpot
A dashpot, also known as a damper, is a mechanical device that resists motion via viscous damping. The resulting force is proportional to the velocity, but acts in the opposite direction, slowing the motion and absorbing energy. It is commonly us ...
* Idle air control actuator
References
Mechanics
Machines
Driving techniques
Automobile engines
Distress signals
{{Mech-engineering-stub