Acceleration/ev bug

In EV, the engine won't run and cannot start it's warmup phases. When you take it out of EV, the engine starts in phase one and you are using a lot of battery- hence the 50mpg and decline in battery charge. I have found it better to let the engine start the warm up phases and keep the battery energy for later use. There has been a lot of discussion about warmup- you can do a search to find them.

 

What is the purpose of your starting in EV mode? It seems that you've made that decision and are now learning that it causes lower mpg. You would be better off doing the exact opposite - Knowing that the car will run the engine intentionally in the morning in order to warm it up, you want to end a day's driving with some pure EV if you can, in order to have the car do something useful during that warmup. Like charging the battery.

Or you could do what I expect would be the easiest, which is just drive the car.

And nothing you do will get great mileage (ignoring that 40 mpg in this use is great mileage) on a single 5.6 mile trip starting cold. It doesn't work that way.

 

Good info. I have been reading this forum a ton over the past 4 days as we are new to EV/HV cars. I was telling my wife to hit the EV button first thing on our PIP and use that up first. Good to know she shouldn't do that.

 

Gotta love this comment. I admit this discussion is enlightening. We pick up our Prius in a couple of hours and this is go info. I don't know if I'll ever use EV mode, but never would have thought about when the ICE runs for warm-up, etc. It does beg the question though. Since we take 304 trips a year, should I switch to EV when I'm out on the freeway with the cruise set or is it moot at that point? Will it cause a lag when going up hills?

 

Yes, running off the battery is inefficient. If you're trying to force the car to operate in some mode it's best to avoid battery use at all times, if possible, unless the battery is displaying that it's -fully- charged (such as after a mountain decent) and then in that case you will be running from it to "burn off" the "excess charge" (or the car will do it for you).

I find the car is usually smarter than me. It's best to just let it "do its' thing". If you want the best mileage, gentle on the accelerator pedal. This will give you ev mode when it is a "good thing", and will avoid it when it isn't.

 

As alluded to by others, the early stage of ICE warmup doesn't produce much power - maybe 1/6th of the HSI bar or so. This phase lasts for about the first minute that the ICE is running. The most efficient thing during this time is to stick to slow speeds and very light acceleration - so it's probably perfect for a leisurely drive to the end of your block. You can basically set your clock by when the car is ready to produce power - the first 12 seconds, the ICE will be off. The next 50 seconds it is on in Stage 1 warmup. After that, it's ready to give you whatever power you need for acceleration - until then, it's going to mostly use your battery power.

So try ditching the EV button for a while, and see if you can find a happy place where your battery stays charged because you're not accelerating too hard too early in warmup.

On the regular "hatchback" Prius, you can't. The EV speed in the US is limited to 25 mph. Until 45 mph, you can still drive with the engine off, but not with the full acceleration that being in EV mode allows. Above 45 mph, the engine is always spinning (though not always burning gas) to prevent the motors from going overspeed. In the PIP, you can stay in EV until 62 mph, at which point the engine has to come on for the same reason.

In any case, it's more efficient to use the engine at that speed anyway - the power you need to counter friction and aerodynamic drag at that speed is high enough that the engine is running in a fairly efficient power range. At 15 mph, it doesn't take much to overcome friction and drag, so EV is fine.

Basically, you should only use EV if you need to move the car from the garage to the street, or if you're going to tool around a parking lot (and not immediately leave), and similar things. If you just have a minute of low-speed parking lot driving before hitting the street, as above, you're better off not using EV and letting the car get warmed up instead.

 

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Thanks, I figured most of that out now that we actually have a Prius, picked up the new car yesterday.

 

Exactly, it's always going to act like that and not produce much power from the engine for the first minute that the car is running - it's behaving exactly as designed, which is to minimize exhaust emissions, which requires warming up the catalytic converter before putting a heavy load on the car. This is not necessarily the same as maximizing fuel economy, as you can see here.

Your only choice is whether you want to change your behavior to (hopefully) improve fuel economy within the limitations of what the car is designed to do or not.

 

So here's what I'm reading:
-- Whenever I'm going less that 25mph for a short distance, I should toggle EV On.
-- Whenever I get in the car, I should start it and put it in EV mode to back out of the driveway.
-- Once on the street, I should toggle EV Off and go about my business.
-- If I run to Walmart or the mall, I should toggle EV On until I find a parking space.
-- When I'm done shopping, I should start the car and toggle EV On until I exit the parking lot.

I will say that the manual probably does a good job of technically explaining the various modes, but sure doesn't correlate those explanations to everyday driving the way folks here do.

I'm reading so much here about the battery that I'm now confused about how long I can use ACC mode to learn the various settings, etc. We just got the car Thursday, so I've been spending a lot of time in the car without driving it and my wife still hasn't driven it.

 

^ Not sure how/where you read that. My take:

1. In a lot of the situations you described, low speed driving around a parking lot as an example: the car will automatically put you in EV. There is no need or advantage in doing it yourself.

2. The only time I would use EV is to move the car a few feet, say off the street, back into the garage, or vice versa. And as often as not it won't allow EV in those situations, due to the engine maybe being too cold, or whatever. When it does I'm happy to use it, but that's all.

 

Mendel, that's just what I've gotten out of reading the posts here. Obviously, I've misunderstood some comments because I assumed it did most of that automatically too. So, what you're saying is if I come home from the market and park in the driveway to unload groceries, I can use EV mode to then put it in the garage. Since the ICE is still warm, it shouldn't come on. If I don't turn EV on, will it come on when I step on the accelerator pedal? Is that even worth worrying about?

 

If the ICE is warm, and if you have plenty of Electric in battery, then when you start your car it will be in electric mode, then the car will go into electric so you can put it in the garage.

 

That's pretty much it. Give it a few weeks, just letting the car decide. Any time the display of instant mpg goes up to the top (US car), you can be assured the engine is off. It's usually apparent by sound/feel too. Above something like 45 mph there will be RPM, but apparently no gas used.

With the car warmed up, when you lift off the gas, then gently reapply but keep the HSD bar below middle mark, the car should stay EV, as evidence by the instant mpg display.

 

Dumb question. What is ICE?

 

ICE= Internal Combustion Engine. Took me forever to figure that one out.

Ramattos I am equally confused at just what the Magical "EV" button really does. You might want to read this running thread too:
ICE vs charging on depleted battery at low speeds | PriusChat

 

It has probably been stated here before, but I think the EV button isn't all that useful. I think the car does a far better job of managing itself than we can by trying to use the EV button. I agree with Mendel Leisk - the only time that the EV button is useful when you are moving your car a few feet (when it is already warmed up)...

 

Went for a ride today and watched the display. Saw EV several times driving around the National Cemetery, etc. Found it interesting to see how my driving habits changed things. Used cruise for a bit to see how that changed things when passing though different terrains. Kind of amazing to see how much even small hills can affect mpg, etc. I'm sure the novelty will wear off, but I've already found myself doing a few things differently to keep that gauge from going too far to the right. Don't think I can deal with the slow acceleration needed for that though, at least not in Phoenix traffic.