ICE On/Off Transition Smoothness

I think so... it use to be I could hardly notice it, now not so much.

 

We have both a 2003 Prius with 100,000 miles we drove and a ZVW30, 2010 Prius with 30,000 miles. I've never felt a transition with these exceptions:

• NHW11 at over 42 mph - shift to "N" and wait for speed to get under 42 mph, shift briefly into "D" and back, the engine will stop and a very faint shutter can be felt. Normally the Prius stops the engine with positive control so there is no shutter.
• One a year, in the fall, the engine will go through about 10-15 seconds of rough running. It happens one in the fall and never again until the next fall.

The Prius control laws actually use MG1 to help mechanically bring the engine to a soft-stop at what we think is a fixed position. But it is so smooth, I have to use instrumentation to tell when it happens.

Bob Wilson

 

I have 64K miles and can tell no difference from when it was new. I am more familiar with what the transition feels like, so I am aware of the transition ... but it is remarkably smooth, and when someone rides with me and I demonstrate the system, they generally are unable to feel the change.

 

I have just under 50k miles on mine and I still have to watch RPM on my ScanGauge to tell for sure the ICE is off. Like Felt above, when I have people ride for the first time they are amazed at how smooth the transition is and ask how they do this so smoothly.

 

OK, here's a related question. On my 2012 Four, especially when the car is not moving, I notice that the sound and feel of the ICE change a little bit for about 1 second before the ICE shuts off. Does the car make some kind of adjustment to the timing or mixture or something in preparation to shut off the engine - does anyone know? Just curious.

 

yes, it sets up for the next 'smooth' start. timing has to be in the right position. does this at every shut down. amazing, isn't it?

 

Not insofar as I can tell. With 68000 miles, I still appreciate how quiet and smooth the transition is. In my opinion, I am more aware of a transition only because I am more familiar with the car. Passengers have no idea if the ICE is running or not.

 

Mine must be as smooth as ever at 77K miles because I don't notice it at all. I usually have to look at the tach to tell if it is running or not.

 

Yours has a tach.? .......Which trim level? .....

 

Not original equipment, I just use the one in my ScanGauge. Along with the tach I usually monitor coolant temps and Amps to/from the traction battery, or sometimes 12V battery voltage.

 

Oh, OK, excellent!

 

To anyone with a Scan Gauge:
I do not know that I actually NEED a scan gauge, but I recognize the information that they provide would be very useful. One thing that has held me back from purchasing the device is ..... where have you mounted the device? How large is it? How about a photo of your installation.

 

I like mine mounted on the steering column using velcro, it's easy to mount and easy to see. But this thread may give you some better ideas, check photos in post #10. Spot for Scangauge? | PriusChat

 

A great, and cheaper, alternative if you have an android is to just get a cheap bluetooth obd with the torque app.

 

Which BT ODBII connector did you get?

 

One of the cheap ones from amazon, can't remember exactly. They should all do the same thing. Just get one of the highest rated ones for 20-25 bucks.

 

i know this is old, buy i'm going to add on instead of starting a new one. I noticed that since my 2010 has over 80,000 miles, the transition is a whole lot more noticeable, especially if cold. sometimes the whole car shakes (slightly that is) when in park or slowly creeping and the ICE fires up.