MG1, ICE, and neutral

This is interesting! I have done a similar thing in my Prius; there is a ‘sweet spot’ of about 1300rpm when cruising on the motorway; also the engine dropping to 950-1000rpm above 65km/h does mean it is worth it to do periods of ‘coasting’ above
65 (one measure of efficiency I think of, which isn’t an official one) is ‘revolutions per mile’ - the less the engine turns per mile, the less the parasitic drag!

Regarding the neutral trick... it can be good if you are going to go above 65km/h and don’t want the parasitic drag; the limit is 100km/h (60mph) before MG1 over speeds. The main advice with this trick is - it will be rare to find opportunities to use it, but some situations (downhill to 55mph, reaching 40mph going back uphill as an example) will let you use it.

My main rule with the engine off neutral trick is : don’t put it back in drive if going over 75km/h (usually limit is 65), and be aware that you may need to brake without regen if picking up speed down a long hill. While MG1 is rated to about 62mph / 100km/h, the mechanical shock of suddenly engaging it at too high a speed may be a risk!

 

I honestly can't understand the sense of even trying to do this.

 

@dolj - agreed! This is extreme hypermiling stuff (and more importantly, is very specific). On my old commute, I had a road where you would be 42mph at the top, 60mph at bottom, 42mph at other side if coasting). I used this trick in that one place only!

This trick would be useless unless you have a place where you go over the ‘engage ICE’ limit (65km/h here) by a LOT, and coast back town to below that limit. Also you need to know the area well so you know there are no hidden driveways where people can come out. And finally - you have to be ready to engage ‘D’ (hand hovering over gear stick) if needed, and accept you could destroy your car if an emergency of some kind happened).

I haven’t done this for 2 years after I moved house. But I got a few % extra mpgs on my commute

 

save it for the track.

If you drive any car weird enough, stellar MPG is on the menu.

To me, the magic of the Prius is that you just buckle up and drive normally, whatever is appropriate for regulation, traffic & weather. Then feel delighted by the fuel savings anyway, because they will consistently be there.

 

I got 270% the ‘EPA’ equivalent, close to a Prius EPA, in an 8 valve 1.8 petrol turbo Nissan Bluebird; that required extreme hypermiling. Back than in 2005-2007 a Prius was absolutely not in my budget!

in terms of safety, putting a Prius in neutral is actually safe (if no cars around). This is because emergency braking by definition disconnects the MG engine braking anyway, to allow ABS to work; it may even be that being in neutral is safer if an emergency stop is needed (at least in the Gen 2 NWH20 where the ‘disconnect’ of the MG-based braking results in the car feeling like it ‘lurches forward’ when any wheel slip is detected; which could result in an accident (e.g. you begin an emergency stop; then you have to react and press harder once the MG braking disconnects) - which by definition requires another period of ‘reaction time’ on the driver’s part, and could result in a ‘near miss’ turning into an accident!

 

What is really interesting about this info is the efect of removing the ICE and fitting an electric motor that spins at 1,000 rpm when above 80km/h ( 50mph) so the computer senses the ICE is running. A throttle pedal for the EV motor actuated by the computer controlled ICE throttle plate would spin it up to what ever RPM the computer determined was required for hill climbing or rapid take off and shut it down to zero for regen only useful if an AC motor is used.

A lot more sensors to spoof so the computer thinks the ICE is still functioning as it should, but still an interesting challenge for anyone with too much time on their hands :lol:

T1 Terry