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I have a question regarding tip #44:
When you *have* to slow down, here's an approximate hierarchy of methods, from best to worst.
1) coasting in neutral, engine off (ie. roll to a stop);
2) coasting in neutral, engine idling;
3) regenerative coasting (hybrid vehicles)
4) regenerative braking (hybrid vehicles)
5) coasting in "deceleration fuel cut-off" mode (in gear, above a certain engine RPM)
6) conventional friction braking (non-hybrid or hybrid)
My car ('99 Miata) has a manual transmission. I have read that when it's coasting in gear the ECU cuts the fuel feed to zero. In contrast, when the engine is idling while coasting in neutral, the ECU not only feeds gas to the engine to keep it turning, but it feeds more gas than when it is idling in neutral at a standstill. You can see this by watching the tach; in neutral, it idles at 1100-1200 RPM as long as the car is moving at all, then the instant the car comes to a complete halt the idle speed drops to 800 RPM.
So if I engine-brake up to red lights or stop signs, momentum I'm trying to burn up anyway keeps the engine turning, which powers the alternator, power steering, oil and water pumps and even the a/c for free (that is, with zero gas consumption), whereas if I put it in neutral and use the brakes to slow down I have to burn gas to run all those appliances.
Am I missing something here? When I finally break down and get a Scan Gauge I'll be able to tell what's going on better.
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