Quote:
Originally Posted by Piwoslaw
Stop&Start systems are getting popular in Europe (I recently read that up to 70% of new cars will have it within the next few years), since it helps in the European fuel consumption test cycle, and helps to squeeze into the next-highest EURO emissions class. New cars have thermal insulation on their cats, which is a good idea for anyone who EOC's or drives efficiently enough to keeps temperatures low.
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The 'stop/start' systems are pretty smart.
What's happened is that, I think Bosch, has developed a system where the starter motor and alternator has been combined, AND (important bit) they have done away with the field coil and gone permanent magnet which gets you from 65% efficiency up to 90%. Then they put in a fast charge/discharge battery system and a computer and suddenly your 'alternator' is producing power at 90% efficiency when you break, storing excess so when you accelerate again you don't load the engine at all.
Once you've done all that then you can get electric air-con electric power steering etc. all driven off 'breaking energy'.. and meaning the engine efficiency at low power is substantially better.
An example is the Volvo S40 1.6Drive start/stop which has 84mpg exurb vs the non-stop/start which is 74mpg.
Derek