2014 Mercedes-Benz CLA250: Stop the Auto Stop-Start
April 18, 2014
Automatic stop-start technology in cars is a divisive issue. On the one hand, it's a not-unpleasant experience to sit at a long red light with the engine off, enjoying a bit of quiet time. On the other hand, we've strived for years to make sure we DON'T stall out in traffic and having a car do that intentionally is really, really annoying.
Especially on my commute.
I can see this technology working well for people who live in the 'burbs. Somewhere with three stop signs, two traffic lights and 20 miles of driving for every minute of stopped-time. That's not my life. My life looks like the page above. On the left hand column is my drive home including a quick errand at, oh, let's say 7pm. The column on the right, which I went ahead and noted correctly, represents the drive into work at something like 8am. Each trip was about 12 miles and took about 45 minutes. The hash marks are the stops. 41 home. 37 back.
A stop per minute doesn't sound bad, but it's hugely annoying, especially in our CLA which has a very noticeable stop-start system. Part of this blame, I think, is due to the engine's nature: It's not quiet to begin with and has a loud starter. The next part of the blame goes to the powertrain layout. The CLA's four-cylinder is mounted transversely. Torqueing an engine that's mounted sideways seems to produce more lash and shake than doing the same with one mounted longitudinally. Something like the Mercedes-Benz GLK, for example, has a longitudinally mounted motor and has a pretty smooth start-stop. Or maybe the CLA's just got soft mounts.
Either way, I'm glad this feature has an off switch conveniently labeled "ECO". And yes, you have to turn it off again each and every time you start it up.
Mike Magrath, Features Editor @ 4,930 miles