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Auto Stop-Start Conversion - 2014 BMW 328i xDrive Gran Turismo Long-Term Road Test
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Auto Stop-Start Conversion - 2014 BMW 328i xDrive Gran Turismo Long-Term Road Test
For a while now, I've resisted using auto stop-start. But after using it in our 2014 BMW 328i xDrive Gran Turismo, I'm changing my mind.
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I'm not an engineer but I think it would be simpler to drive the engine with an electric motor while cutting spark and fuel during stops. Since the engine is still turning and driving the belts, the AC and water pump will still work. Then when the engine needs to actually do work, it can start whenever to add fuel and spark back in.
If such a system exists, it would eliminate all the complaints about start/stop.
The concept is good, current execution needs to be better. It probably will be in time.
Other than that, money saved on fuel is minimal since you're shutting the engine down during a low consumption period, and a car with "stop-start" will be more expensive than one without. The advantages of cutting emissions are very real though, especially since the environments where this kind of system shines are usually the most prone to heavy pollution, such as dense population centers with heavy stop and go traffic for example.
A moment of welcome quiet? Exactly how noisy is the cabin of this BMW at idle in gear? Come on.
I like Mazda's start-stop system. It stopped a piston just after top dead center. When it's time to re-start it just fired a spark plug instead of engaging the starter. Too bad it never/hasn't made it to production.
Why is that Europe uses start/stop more than anyone and MB and BMW still can't smoothly restart the car? Ford and GM engineer the smoothest systems yet it's not widely available in America.
I rented a C-class last year in Frankfurt that had an auto-stop system. Besides the initial shock when the engine cut out at my first red light, I found the system to be just fine. It really didn't interfere with my driving at all, and it was nice knowing that I was creating fewer emissions while "idling" during a stop. If the EPA fuel economy tests took this into account, we'd see it used more often in the US.
In my opinion Europe is a bit better suited to this because of their traffic lights. When stopped at a red light, the yellow light will come on again just before it changes to green. This gives the driver just enough advanced notice to lift off the brake and trigger the auto-stop system to refire the engine before the light turns green.
Newer hybrid engines use electrical water pumps.
I can confirm that this is not true. I drove a POS Ford Fiesta 1-liter ecoboost in Europe, and that thing had the most intrusive start/stop system I've ever seen. I thought the engine was tearing itself apart whenever I push the clutch pedal to restart it. In contrast a VW Polo I had later on was relatively smooth.
My Jag XF has stop/start. As someone mentioned earlier, once I realized the car hadn't "died" at
stop (ghosts of Jag/Lucas electronics past), I don't find it all that intrusive. Do have to adjust your stops a bit though to use it best i.e. if you stop, system stops engine, then you immediately lift the brake to creep forward, starts the engine and may not stop it again.
'21 Dark Blue/Black Audi A7 PHEV (mine); '22 White/Beige BMW X3 (hers); '20 Estoril Blue/Oyster BMW M240xi 'Vert (Ours, read: hers in 'vert weather; mine during Nor'easters...)
I like automatic start-stop systems but most Americans aren't ready to accept it.
For the record, I've been manually cutting my engine on my cars for many years now. Of course, I only do it when it is appropriate (engine warmed up, it's above 3°C outside, etc...) but it seems wasteful to idle now. Feels good saving fuel and money instead of puttering at a standstill for minutes.
There's your problem right there. Unless we're talking about temperature extremes, I'd rather ride a bike than do a car commute where I don't even move for several minutes.
I have a really easy commute, 10km one-way with a whopping 4 lights. However, the wait at intersections can be long if you are on the "non-main" thoroughfare during peak hours, or waiting for the left turn light for a freeway onramp.. Then there's the freight trains at RR junctions.....
At a very long light I might shut off the motor but beyond that I don't feel it saves enough gas to justify the hassle. Not to mention how much life does it cut from the starter motor?
@mlin32, say no more, I've definitely shut off my engine waiting for freight trains too. Could've gotten out, stretched my legs, and eaten lunch by the time some passed! Sounds like those four traffic lights of yours need to be redesigned though, if you can stand the time construction will take...