Glide over 41 mph. Possible?

Hi Mike. It actually cant start the engine in neutral. What it does do though is if you try to shift to neutral above 42 then it starts the ICE first and then goes to neutral. If you shift to neutral below 42 MPH however then the ICE stays off even if the speed increases above 42 (due to speed building up downhill for example). This is what some people do to coast in "N" above 42 MPH. And yes there is a risk of over-revving MG1 if you do this and go too fast.

 

As Kayak_Hauler mentioned, the HV ECU keeps the ICE spinning at over 42mph. This consumes several hundred watts if you are gliding over 42, which isn't too bad. The A/C typically consumes more!

When in neutral the system will still use this power when over 42mph, except that if you start at below 42mph on a down hill it won't spin up the ICE until 52mph.

On my PHEV, when I'm in forced EV mode, my controller basically forces 100% warp stealth over 42 mph, so I can drive solely from the battery at any speed, but of course taking the extra power hit to spin the ICE.

The advantage of neutral is you can let go of the throttle. The disadvantage is if you hit the brakes in neutral, you get no regen.

Incidentally hitting P or R at speed will instantly put the car in Neutral.

 

Simple answer to your question, Yes its possible.. hard at first to get the footing correct.. Once you do it and get use to it its simple.. and not this isn't wrapped stealth

 

That's handy to know pEEf. I knew that if you started a downhill glide below 42 MPH that you could exceed 42MPH and the ICE still didn't spin. However I didn't know that it kicked in at 52MPH regardless. That's really good to know, since it means MG1 is always protected from excessive RPM.

 

Yes, the HV ECU won't allow MG1 to overspeed even if you run out of gas, etc. When it spins the ICE, it sets a CAN frame the puts the VVTi in a mode to reduce pumping loss.

 

Yes I'd heard that about the VVT pEEf, but I've always wondered just how much scope for change there is in the valve timing. Does it just keep the valves open for as long as possible or is there a better strategy for reducing pumping losses?

BTW. My understating of the VVT is not that great. But I think it has just fixed exhaust valve timing and some limited control on the intake valve timing. Is that correct?

 

Yes, VVTi only modifies the Intake timing, but it can move it such that they don't open for the intake cycle, and thus no air=less to pump.

 

So is it safe to assume that you CANNOT ever over rev MG1? Is it safe to assume you can start down a hill a zero in neutral and go until 70 MPH without damaging the transmission?

I like using neutral but stopped when I saw posts about how it can damage the Prius.

 

My tests indicate as long as the car is in Ready, it will protect MG1. YMMV!