What's Wrong With This Picture: Land Of The (Stop-Start) Free Edition

Edward Niedermeyer
by Edward Niedermeyer

America has always been a land of extremes, and our automotive scene is no different. While current automotive debate obsesses over a high-efficiency halo car, our domestic auto industry is mounting a comeback largely on the back of pickups and large cars and crossovers. Meanwhile, we’re falling behind in the quest to make all cars more efficient with practical “bolt-on” systems like “stop-start” or “microhybrid” systems that turn off gas engines at stops. So what are we missing out on? According to a report from SeekingAlpha, stop-start systems provide

estimated fuel savings range from 5% in government mandated tests and 10% under real world city-highway driving to almost 20% in congested city traffic

Which would provide a hell of a lot more fuel savings than any high-price, limited-production eco-halo car. But, as Mazda has complained, the US EPA test cycle doesn’t provide any Monroney Sticker advantage to stop-start systems, even if they provide real-world improvements in fuel efficiency. Maybe instead of trying to keep EVs and plug-in halos on subsidy life support as long as possible, our government should be looking at ways of incentivizing across-the-board efficiency improvements like those offered by stop-start systems.

Edward Niedermeyer
Edward Niedermeyer

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  • Facebook User Facebook User on Oct 14, 2010

    I'm sure it returns better real-world gas mileage, but being someone who drives at least 1/2 miles during non-rush and has exactly 1 light between the highway & the house (town of 27k) I'm not sure how much it would add to my gas mileage...

  • Steven02 Steven02 on Oct 14, 2010

    I am guessing that in 5 or so years, you will start to see this on many vehicles. Fuel economy regs getting tighter, this will help... just got to get this into the testing somehow.

    • Dhanson865 Dhanson865 on Oct 14, 2010

      easy peasy, just add a Drive Thru test cycle. America is the land of fast food. EPA cycles would then be: Drive Thru City Highway Combined I'd suggest the Drive Through test be normalized to the equivalent of sitting in a drive through with 5 cars waiting taking about 15 minutes to complete (http://www.qsrmagazine.com/reports/drive-thru_time_study/) City cycle * Trip length: 11 miles * Test time: 31 minutes * Number of stops: 23 * Time spent idling: approx. 18% * Maximum speed: 56 MPH * Average speed: 20 MPH * Engine temp at startup: Cold (75 degrees outside air temperature) Drive Thru Cycle * Trip length: 0.01 miles * Test time: 15 minutes * Number of stops: 7 * Time spent idling: approx. 98% * Maximum speed: 3 MPH * Average speed: 0 MPH * Engine temp at startup: Warm Then just decide what percentage it'd take to make the Drive Thru cycle barely affect the combined mileage. I haven't done the math but something like 10% Drive Thru/50% City/40% Highway seems reasonable adjust the mix of the 3 tests until the Yukon/Tahoe/Sequoyah look worse without making them look any worse than you have to and without making the Prius look unbelievably better than it is. If there is any political backlash on the name "Drive Thru Cycle" call it "Traffic Jam Cycle" instead and bump the max speed up to 13 MPH, lower the idle time to 50%, and increase the Trip length accordingly.

  • Obbop Obbop on Oct 14, 2010

    Combustion interruptus.

  • Greg Locock Greg Locock on Oct 14, 2010

    Of course there is nothing to stop you manually stopping the engine at each stop, for a week to see if it is worth it. I bet you find the fuel savings are minute. In my case my car use about 2 pints of fuel per hour when stopped, even with the AC running flat out. SO in my 6 hours of driving a week I spend perhaps 20 minutes at idle, 3/4 of a pint saved out of 6 gallons. Um, every little helps, but color me unimpressed.

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