When I turn on my car, stop at a light, or just have it in park it hovers around 750 rpm (my older car sat at like 1-1.2k rpm). But why? It’s not moving the car or anything. I know some modern cars turn off the engine if it idles for too long but that doesn’t really explain why. Also when I coast on the highway it will idle at even higher rpm’s. I would have expected the automatic transmission to shift down when it’s not applying any acceleration.
Furthermore, do electric engines idle at a rpm? If not does this make electric cars more energy efficient?
In: 126
Theres a minimum rpm needed to keep the alternator running. Depending on the type of vehicle you have, the alternator output may be different than another vehicle…truck with a tow package vs a sedan. Of course if you’re cruising on the highway the rpm is going to be higher…cause you’re telling the engine to spin faster. Even if you take your foot off the gas, the engine is physically connected to the wheels via the transmission. The inertia of the car is keeping the wheels spinning and thus the engine to spin. Heres an experiment for you to do…find a hill in the town. Get up to speed and notice the rpm, then put the transmission in neutral and watch the rpm drop. Thats because you’ve physically disconnected the wheels from the engine and now there’s no load on the engine.
Latest Answers