Automakers adopt start-stop systems

By Nancy Dunham

Automakers hope start-stop systems will satisfy consumers’ love for large, high-powered cars while also meeting the Environmental Protection Agency’s fuel economy standards. The auto industry in 2019 was awaiting final word whether the federal fuel economy standard of 54.5 miles per gallon (mpg) for automaker fleets by the year 2025 would instead be frozen at the 2020 standard of 37 mpg.* Automakers stepped up the adoption of start-stop technology as deadlines loomed.

*Regulations for Greenhouse Gas Emissions from Passenger Cars and Trucks, rulemaking announced August 2018.

Here are a few things you should consider about start-stops and how they may impact your driving experience.

How start-stop technology works
Start-stops represent an engineering approach for tackling fuel economy challenges. The primary goal of start-stop systems is to save fuel. Reports from estimate three to 10 percent fuel savings depending on various factors. Longer stops result in more fuel savings. So if a car usually gets 20 mpg, a start-stop system would increase fuel efficiency to a maximum of about 22 mpg.

You may have read or even experienced how start-stop systems seem to automatically downshift when the driver presses the brake and brings the car to a halt, such as at a stoplight or in heavy traffic. When a car equipped with start-stop technology comes to a complete stop, the start-stop system cuts spark and fuel to the engine, which saves fuel that is otherwise used to power an idling, non-moving car. Engineers have worked to ensure the start-stop engine almost instantly restarts when the driver disengages the brake and presses on the accelerator.

The effect on driving

Some drivers dislike start-stop systems, saying they are noisy and make the cars seem to tremble or stall. Indeed, it’s been reported that about 40 percent of drivers at least temporarily disable the start-stop technology in their cars. According to auto enthusiasts, drivers of high-end luxury cars are less likely to find issues with the technology, noting that those cars have noise-cancelling insulation and more refined start-stop systems.

Adding start-stop to your ride

Auto experts recommend against retrofitting a car with a start-stop system. The car’s starter, battery, computer system and more would need to be modified to accommodate start-stop technology. Not only would those efforts prove costly, but chances are also high that start-stop may still impact the car’s computer and other electrical systems.

Vehicles with start-stop systems

Start-stop systems aren’t new. In 1983, Volkswagen introduced its first production vehicle with start-stop in a European model, but the technology took more than 20 years to gain momentum in the US. Now, vehicles with start-stop systems represented 38% of Ford’s 2018 model year production, and 24% at General Motors.†

†US Environmental Protection Agency, March 2019, Highlights of Automotive Trends Report, analysis of 13 large global auto manufacturers.

2020 model year vehicles with start stop systems include the Ford® Fusion SE, the Ford® Edge SUV, and the Ford® Escape SE SUV,‡ to name a few. At General Motors, the 2020 Chevy Silverado 1500§ and the 2020 Chevy Malibu 1.5L Turbo are just a few of the models for which automatic start/stop is standard. Given the growing adoption rate by US and European automakers in a wide variety of models, it’s important to know what start-stop technology is all about, especially since it might play an important role in your next car purchase.

Nancy Dunham is based in Washington, D.C. and writes for Automotive News, National Automobile Dealers Association and other major publishers.

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