I've noticed that my 2010 Prius sometimes starts up the ICE briefly while braking. It seems to happen almost 100% on the time when passing about 70 kph (43 mph) when exiting the highway on my commute home, which means under the following circumstances: About 30 min of driving 120-140 kph (75-87 mph). Approach exit driving about 120 kph (75 mph). Release throttle to slow down to approximately 100 kph (62 mph). Gently brake to 50 kph (31 mph), with constant pressure on the brake pedal and not touching the throttle. While braking, the ICE starts up at about 70 kph (43 mph) and immediately shuts down again. It can feel this, hear it, and see the fuel usage indicator go up for a brief moment. The car continues to decelerate normally though. Is this normal? It seems fairly pointless (though probably harmless). The car is in normal mode (that is, not eco, pwr or EV).
That's an interesting thought, but then I wouldn't expect it to always happen at the exact same speed. It's also noteworthy that this is the same speed that seems to be the maximum for driving purely electric.
when i had a regular commute in my 2008, at the end of the highway run, fully warmed engine in summer, the last mile on a back road at 20 mph or so would always see the engine come on every time. but the battery was full from the highway. not sure if it relates to your situation at all though.
That's the max speed 3rd gen Prius will run without the engine kicking in. Happens to us everytime we coast down a steep hill. That's correct.
The ICE will always spin when you're faster than 70 km/h, the Prius injects some fuel (making it look like the ICE is starting up) while braking through that speed to let the transition from spinning ICE to ICE off go smoothly. This is perfectly normal.
Yeah. The one place I notice this is rolling down this hill. Pretty much foot off the gas (maybe a slight touch to defeat regen) the car will accelerate, and at the bottom of the hill the limits goes from 60 (kmh) to 80. Somewhere around 73~74 kmh, the engine kicks in. Always. Rough conversion from kmh to mph: 74 x 5/8 = 46
What the exact speed is is not really interesting. Especially while braking you can not say it will happen at exactly that speed, and european speedometers also have about 8% offset in speed. It may also not be so noticable on MPH speedometers because of how the consumption gauge works. On european cars it is usually in liter / 100 km and will indicate nothing when the foot is off the gas and it will blip a few bars when the ICE is turned off. On US cars the gauge will stay full bars when the foot is off the gas (99 mpg) and will probably not dip a single bar because the mileage will not drop below 99 mpg.
Mine does the exact same thing, but I'm not sure about the speed, I thought it was at different speed every time, I'll start to observe it. I'm pretty sure that's not connected with the battery condition, because mine was dying and I've replaced it and it continued to start the ICE for 1-2 seconds.
