Start-Stop Technology Shows Potential

Carmakers are looking into every possibility to increase fuel efficiency in light of the upcoming 2015 CAFE increases. One fuel-saving technique that looks promising is start-stop technology, commonly found in today’s hybrid cars and SUVs.

How many gallons of gas and pounds of greenhouse gas emissions are wasted and emitted each year when vehicles are sitting in traffic or at stop lights and signs? The Department of Transportation estimates that 17 billion gallons of fuel are spent each year while cars sit motionless.

A German transmission company, ZF Friedrichshafen AG, has introduced a technique called hydraulic impulse oil storage that stops fuel consumption when a non-hybrid car comes to a halt and restarts it within 350 milliseconds of the brake being disengaged. This reduces fuel consumption on starts by 5%.

The advantage of start-stop technology is that it’s relatively cheap to manufacture, and if implemented widely it could cut the use of millions of barrels of oil and reduce greenhouse emissions. Some people in the automotive industry think that one in five cars will use start-stop technology by 2015.

Start-Stop Technology Gets Another Boost—and Some Efficiency as Well (Autopia)

Comments

Even higher savings would be achieved if automatic transmissions would 'free wheel' when no gas is being applied. Dwarfing the stop light idle loss is the extra drag built into every automatic transmission. This low energy glide combined with engine auto-stop and we would be looking at a substantial mileage improvement greater than 15% in urban traffic.

We have the computers and the technology so this automatic glide can be completely safe. All it takes is the will.

Bob Wilson

If I'm correct, BMW is introducing stop-start technology on ALL their cars (at least, in Europe). It's part of their "efficient dynamics" mantra I believe. I know the EUropean version of the new Mini will be getting it, o rmay in fact already have it, and the 1 and 3-series will also be rolling out on it I believe. It's a very simple way of saving fuel...

Often, I simply turn off the engine on the traffic light. My wife goes nuts when I do this. I guess she is the one who needs that technology

It is useless for people who time the lights perfectly?

What are you talking about Bob Wilson?

With modern automatic transmissions, on overrun, the torque converter stays locked up, and the fuel injection is cut.

If the automatic transmission freewheeled, the fuel injection would have to stay active so the engine wouldn't stall. That would cost fuel/money.