While going to work this week, I was concerned at the sound I thought I heard coming from the engine- so I quickly turned off the radio so I could listen. I was going down a long hill, and had my foot off the gas. Teh engine was revving very hard and long. Does anyone know what this is? Has anyone else had this happen?
engine warm battery charged Ie: top of scale and green in D Normal computer tells engine to run and that slows the MG1 and that pulls charge out of battery so there is spare capacity for regeneration. In simple terms. This has been documented several times early on in the PriusChat main form.
Was the car in "D" or in "B" mode? It almost sounds like it was in "B" mode which uses the engine to slow the car down like a jake brake on a big rig truck.
Need to differentiate between ICE and MG1. I would defer to Frank Hudon's answer. Note that in B mode it is the regenerative braking that is kicked up a notch and that it is not the ICE doing the braking. (ICE = Internal Combustion Engine for newbies)
Frank is right. That's the car using the Motor to spin the ICE to bleed off excess electricity. It may even continue after you reach the bottom of the hill until the system is happy. In theory, it could also be "B" mode you're hearing, but that is less revvy most times. There are really 2 "B" modes. If you are going >20 MPH, the car will spin the ICE and use it for braking, just like downshifting. If you are going <20 MPH It will increase regeneration, and won't spin the ICE, which is nice because it won't kick you out of stealth if you're stealthing along.
