how fast to accelerate to speed?

My Prius C uses a key to start, but I don't think I've ever had the engine start immediately. There's always about a 5-second delay before it engages, which gives me plenty of time to hit the EV button. As long as the battery is at least about half charged, that prevents the ICE from starting while I'm backing out of the garage (it's a tight fit and so I take it pretty slow).

Of course there are plenty of times when the battery state of charge is too low and "EV Mode" won't engage. That's life for you.

Other than that ability to (sometimes) prevent the ICE from starting immediately I haven't personally found much use for "EV mode" since judicious use of the throttle can avoid running the engine in a broader range of situations.

 

A five second delay is something I would actually mention to the dealer as I had the understanding that it would go into Ready mode immediately. I think turning a key is just a formality and you should have an immediate start. My ICE will yield to EV when standing still as long as the battery is sufficient. Maybe I should try the mode switch anyway. The highest gas consumption is at the start. It evens out, but the meter shows ghastly numbers before it does. In one block distance I get something like 8 miles to the gallon. In one mile I get 65. Same trip.

In situations sometimes where I am running on EV, from the system switching over, I would put it in B gear. Someone driving a BMW i3 in a garage told me that this electric car engages an automatic braking of the engine when taking the foot off the gas. I tried the B gear which is an engine brake and battery regenerator, and the same thing happens on the Prius C on B in an EV mode. It conserves the use of the battery! (Seems to me)

 

B almost always results in lower MPG than D. (Under 24 MPH, B can be used to increase regenerative braking) B is designed to be use to descend long downhills.

I view acceleration as follows: Cruising is good, my v gets about 45 MPG when cruising at 60 MPH. Accelerating is bad, it get about 15 MPG while accelerating. So I minimize accelerating and maximize cruising by accelerating briskly.

 

It does go into Ready mode immediately, and if I put it in gear and press the accelerator pedal gently then the car will move under battery power. But the gas engine doesn't fire up until about 5 seconds after the car has been turned "on", and that is true whether I press the accelerator or not. The exception is if I put it in Neutral (and this may be true of Park as well), in which case the engine doesn't fire up until I put it in gear (or until about 5 seconds has elapsed, whichever comes last). Or if I start it up and immediately hit the accelerator hard then the gas engine will fire up sooner.

I'm pretty sure this is all perfectly normal behaviour for the Prius C.

I only mention all of this because the one use I've found for the "EV Mode" button is to prevent the engine from firing up once the car has started and been put into gear. I suppose a better alternative would be to put the car in Neutral (or leave it in Park if it works that way too), which has the advantage that it seems to work even when the battery is depleted beyond the point when the "EV Mode" button is effective. But that's not how my habits have seemed to behave so far - perhaps I should work on that...

 

Using B while in EV (manually or automatically engaged) can't decrease mpg because no gas is being used. Using it in conjunction with the ICE probably would because it is reducing function. I use B when needed for the purpose and usually it is in EV but sometimes on a downward hill.

 

If the extra drag of "B" mode causes you to slow down more than you need to, then you need to use more power to speed up again. In that sense, "B" mode can result in worse fuel economy, not from the braking itself but from the need to accelerate to speed again.

 

I'm not using B mode for speed. It is a braking technology. Use it in EV (no gas) and it decreases consumption of the battery while regen too. While in EV and D drive gear ratios, we have to modulate our acceleration. While in EV in B mode, taking your foot off the accelerator applies braking; then applying the accelerator again moves you again, still in EV (unless your battery is down, at which time the B mode may in fact consume extra gas and you are not in EV. EV and B, save the battery charge. ICE and B, downhill.)