Start-stop system

A vehicle start-stop system or stop-start system (also known as S&S, micro hybrid, or micro hybrid electric vehicle (μHEV))[1] automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby reducing fuel consumption and emissions.

[4] In a manual transmission vehicle, stop-start is activated by stopping the car, shifting the gear to neutral, and releasing the clutch.

With the air conditioning and fan at maximum settings, the supercapacitor will be drained in five seconds, and the engine will automatically turn on.

[9] Start-stop technology was introduced in Europe first because of regulatory differences: 25 percent of the New European Driving Cycle (NEDC) is spent idling,[10] while only an estimated 11 percent of the United States Environmental Protection Agency (EPA) test is spent idling.

In a car with a manual transmission, engine shutdown typically occurs when braking to a complete stop, shifting the gearbox to neutral, and releasing the clutch.

If the car is slowed initially by manual use of the automatic gearbox and final stoppage is achieved by using the handbrake, the engine will not shut down.

In the 1980s, the Fiat Regata "ES" with the City-matic system[15][16] and Volkswagen Polo "Formel E"[citation needed] also used similar devices.

The Citroën implementation combines a SensoDrive automated gearbox and an electronically controlled reversible alternator[28] or integrated starter-generator (ISG).

An ISG, also known as "integrated starter-alternator", combines the role of the starter and alternator into one unit; manufacturers include Valeo[29] and Denso.

[34] Formerly, only the 2.7-liter turbocharged V-6 version came with stop-start, which requires a more robust (and expensive) absorbent-glass-mat (AGM) battery that can better handle the constant cycling and the heavier draw from vehicle accessories with the engine off.

[36] In 2014, General Motors announced that the Chevrolet Impala and Malibu would have a (non-eAssist) start-stop system across all models.

The redesigned 2012 Kia Rio and Rio5 (hatchback) debuted at the 2011 New York Auto Show was announced with their Intelligent Stop and Go (ISG) feature, or stop-start technology.

The mixture in this cylinder is ignited by the spark plug, forcing that piston down, and with assistance from the starter motor, results in a near instantaneous engine restart time of 0.35 seconds.

[41] In 2011, Mazda announced i-ELOOP, a system which uses a variable-voltage alternator to convert kinetic energy to electric power during deceleration.

The energy stored in a double-layer capacitor, is used to supply power needed by vehicle electrical systems.

When the driver lifts off the throttle or brakes, the ECO motor is driven as an alternator to maintain "sub-battery" charge.

More recently, Toyota has been selling cars with start-stop system on their internal combustion engine vehicles since 2009, and since 1997 in their Prius hybrid line.

For the Lupo 3L, with an automated manual gearbox and clutch, the engine stops four seconds after the car becomes stationary with the driver's foot on the brake pedal.

Gasoline and microhybrid vehicles, on the other hand, generally experience slight delays (albeit fractions of a second).

In February 2001, the US National Highway Traffic Safety Administration (NHTSA) raised questions about non-hybrid Honda vehicles equipped with the company's "Idle Stop" transmissions due to concerns over the "sudden lurching forward of a vehicle in an automatic restart" – rather than the "gradual creeping forward found in current transmission designs".

[52][53] A common issue of stop-start systems is that long-term use may induce additional wear due to lack of oil lubrication.

However, in a vehicle with a start-stop system this effect can necessitate new technological solutions to avoid premature bearing wear, depending on the driving cycle.

The Mazda i-stop used in the Mazda3/Axela line (in Europe and JDM) uses combustion to assist the starter motor by sensing the position of the piston in the cylinder.

[46] Many vehicle consumers have expressed frustration over what they perceive as government overreach, inconvenience, and annoyance regarding the required auto stop-start feature.

The Environmental Protection Agency (EPA) currently offers gas mileage rating incentives to car manufacturers who ensure their auto stop-start systems default to the "on" position.

Since that average will always be lower than the economy with the system engaged, car manufacturers choose to switch it back on when the vehicle is restarted.

This inconvenience leads many consumers to either live with the hassle of pressing the button each time they start their car, search for aftermarket workarounds, or avoid vehicle models with the feature altogether.