More and more automakers are using engine stop-start systems to increase fuel efficiency. This type of system, which shuts down a car’s engine at idle and immediately restarts it when the driver presses their accelerator, is evolving into a popular technology. It is a feature of all hybrid cars on the market these days and now we are starting to see them on conventionally-powered cars.
How the systems work
The wizardry behind engine stop-start systems is the main CPU that controls the vehicle. Stop-start systems are made so that depressing the brake pedal sends a “ready” signal to the engine controller. When the vehicle arrives at a complete stop, the controller shuts down the engine and pre-positions the starter motor, fuel injection system and transmission to provide a rapid engine restart. This occurs when the driver either depresses the accelerator pedal or releases the brake pedal. Many systems aim for the restart to occur in half a second or less.
They conserve fuel
Stop-start systems can cut combined city-highway fuel consumption by as much as 10 percent, and even more when they are combined with hybrid drive systems. By eliminating engine idling, stop-start systems also reduce smog-causing and toxic tailpipe emissions. They are very effective in city driving situations where a lot of stop and go driving occurs.
What else stops
If you turn off the engine in your vehicle, the air-conditioning stops, too. That is because most A/C systems use the engine’s power to run their compressors. Losing your cabin AC is not a big problem on mild days, or when the stop period is short, but it could be on hot ones. What the auto manufacturers have done to address this is to place circuitry in that simply boots the engine back on if the cabin temperature gets too high.
Battery Usage
Stop-start systems aren’t hard on engines, but they do demand a lot of the car batteries. While a conventional car or truck may call for high amperage for the starter-motor a few times every day, a vehicle equipped with a stop-start system could cycle that drain on the battery several dozen times each day. This is harder on the battery and automobile manufacturers generally put large batteries in cars that have stop-start systems.
A Possible Downside
Is there anything negative about a Stop-start system? Well, many drivers find it disconcerting when the engine shuts off every time they come to a stop. There is some “getting used to it” involved.
This Isn’t a New Thing for Hybrids
Stop-start systems are nothing new for people who have hybrids. These vehicles always have incorporated stop-start for years to improve fuel economy. Unlike stand-alone stop-start units, which need 12-volt batteries to help keep costs down, hybrids use their electric-drive systems’ robust but expensive lithium-ion and nickel-metal batteries. Because of their effectiveness and simplicity, stand-alone stop-start systems may become common place on new cars and trucks in the U.S. in coming years.
Thank you to the service department at Fletcher Chrysler Dodge Jeep RAM in Franklin, IN, for sitting down with us to discuss start-stop systems!