Hi gang, I was wondering if anybody is having a similar problem with their 2010 Prius. Whenever I am at a complete stop, and then I begin accelerating, my Prius "shudders" around 8 mph. This happens about 90% of the time... it almost feels like the Prius is having a difficult time "switching gears" from 1st gear to 2nd gear. Does anybody know what this shuddering is, and if it is normal or if I have a problem that needs to be fixed? I brought it into my Toyota dealer and of course, for the first time in 6 months, I could NOT reproduce the problem while the technician was sitting in the car with me. Go figure. As soon as I drove away from the dealership, the issue was there again. Any ideas? Thanks! Scott
From what I understand, and I am sure one of the resident experts can chime in with the details, but when you first take off from a complete stop, you are using MG2 to accelerate up to about 10 mph (depending on how hard you are accelerating). Then the ICE kicks in and assists with the further acceleration. What you may be feeling is the ICE starting around 8 mph. I would not consider mine to be shuddering, though I can feel the ICE when it starts and stops.
And if the engine is "cool" it tends to shudder more when starting up. By the time the OP gets to the dealer the ICE is warm and shudders less when starting.
Thanks so much for this explanation... it always makes me feel better to know that I'm not crazy! I know that ICE is internal combustion engine, but what is MG2? Thanks, Scott
It's the ICE or gas engine starting. it's normal. Also our cars have no gears so they never shift. MG2 is the main electric motor that drives the car.
MG2 is Motor-Generator 2. It is the big electric motor used to move the Prius and do regenerative braking. MG1 is Motor-Generator 1. It is the small electric motor used to start the internal combustion engine (ICE) and act as a generator powered by the ICE. As pointed out above, the shudder is the ICE starting. Also pointed out above, the Prius never shifts gears. The gearing is fixed, and always engaged. Tom
Awesome, thanks so much for all the replies from the experts! I really appreciate it! I should have posted my question here first before taking it into the dealer! hwell:
Hahaha!! :lol: Well, I couldn't reproduce the shudder when I was there (perhaps I wasn't accelerating quickly enough or slowly enough, or perhaps the car had warmed up as spiderman suggested), but the guy seemed MUCH less knowledgeable about the Prius then the people on this forum! He didn't even mention that it could be the car's ICE starting up. He basically said, "I've never heard of that problem before... bring it back if it happens again." Funny that there's such a large disconnect between the technical information available on this forum vs. the information that is known at the dealerships.
I spent dozens of hours learning about the prius. It does seem like the dealers don't know much at all. You will notice the harder you press down on the pedal the harder the ICE kicks in. I still noitce my car doing this. In a perfect world we wouldn't be able to notice it.
Amen to that! The dealers should require their service personal to read the forum on a regular basis.
Not sure if I have this exactly right, but I believe I read that the Prius starts its engine by spinning it up (using the smaller electric motor MG1) and then adding gas/ignition to the chambers one at a time until all 4 are "lit". (unlike traditional engines which spin and add gas ignition all at once to all chambers) With a warm engine, this is almost transparent - and as spiderman said, with a cold engine this is rougher. It is also more noticable at lower speeds, when there's less wind noise and the engine isn't spinning as fast. (and if you're really into the technical detail, starting the ICE "pushes" against the outer ring gear, which is what sends power to the wheels, so you're likely to feel that as a slight variation in acceleration until the ICE is running and the computer smoothes things out) If it still shudders when warm, then you might have a problem - but a little roughness when cold is pretty normal.
My Prius has a similar shudder when I accelerate moderately or rapidly. It does not shudder when I am gentle on the pedal.
I noticed it too but as others have said I figured out it was the normally unnoticable ICE starting up. This is usually only noticable when the car is cold. Check out the Insight posts...in the Honda every ICE start up is plainly noticable.
