MPG B Mode Trick

what does this do to pollution?

 

This makes no sense to me because..........if nothing else is calling for the engine to run, like A/C or low charge in the HV battery, then mine DOES shut off immediately. Well within a couple of seconds.

 

I find the engine shuts off in D, just fine. Fully warmed, it'll have shut off even sooner: while coasting up to the light.

One trick I DO use, with engine only partially warmed: shut cabin vent system off: that'll often tip engine shutdown, especially in colder weather when it would otherwise stay running.

 

Yeah we use AC mainly in winter, when it's really rainy and all other measures have failed, windshield is too steamed. Just cracking the windows and using heat/defog will usually allow avoidance of AC.

We're finally getting out of the fridge up here, was unusually protracted winter for the BC "wet coast", still a few isolated snow clumps around.

But in summer yeah: vent system off, just use the windows to control interior conditions.

 

Here is an even better trick: don't use B at all on flat roads, just leave it in D. As you slow down below mid-40ish mph, long before actually reaching the stop line, the engine will stop. This gets it shut off far far sooner than when trying your trick above.

B mode is intended for certain types of mountainous terrain that simply don't exist in Florida.

 

There is only ONE instance I use B here: coming down Mount Seymour. It's really poorly explained in the Owner's Manuals. Priuschat members seem to have settled on something along these lines:

B mode is appropriate for protracted, steep downgrades, where there is a danger of the hybrid battery being charged to the point that regeneration braking will no longer used. It employs engine braking, reduces the need to use brakes, and reduces charging rate. When the hybrid battery is fully charged and no further regen braking is allowed: the conventional friction brakes will be the sole means of slowing the car, and could become overheated.

 

I would just put it in D and fugedaboutit. Rolls easier, better charging.

 

That is not relevant to the B vs D issue. Just leave it in D, then lightly use the regular brake pedal to keep the same speed profile.

The brake pedal should use nearly pure regeneration if used lightly, whereas B mode will divert some of that power into engine drag. Regeneration power is limited by what the battery can accept, and the regular brake pedal can hit that limit as easily as B.

B does not harm the car at all. It only throws away some energy, possibly decreasing MPG slightly when used unnecessarily.

Your great MPG results are likely coming from some other elements of your driving style.

 

i think bob wilson pulls over and shuts the car down during warm up.

 

It's a C so a comparison might not be appropriate.
I typically get a bit more than others in town below 50 MPH and a bit less on sustained highway runs.
And that is without any special considerations or procedures........except trying to anticipate the traffic flow to minimize having to come to a complete stop.

 

Making yourself a traffic hazard is somewhat more important than eeking out an extra couple of MPG.
B mode won't hurt the car but it might hurt YOU.

And upon what are you basing that gain......the built-in calculation or actual miles divided by gallons put in ??

It is sometimes possible to "fool" the built-in calculation so that it "lies" to you.

 

In itself, B mode isn't the problem. Any hurt would be from the driver's road style, colliding with an aggressive local traffic style.

 

My fellow drivers are usually drafting, pulling out, swerving back in. I'm incorrigible, always doing nutty stuff, like:

1. Abiding by speed limits.
2. Coming to full, legal stops at stop signs and red lights.
3. Maintaining safe following distance.