Full-battery downhill engine start is a pain!

Is there not a 80% charge option like on the Nissan Leaf? Does the PIP not have any charge controls (only charges to 100%)?

The ICE starts for sure when the battery reaches 84%. I have one trip logged (using Torque with help from USB and Vincent) where the ICE ran for almost 5 minutes exactly after it started due to this condition.

The idea to start charging later is OK if you dont mind possibly NOT having a full charge. What I mean is, in my case, if I unplug and lose, say, 1 mile. And I regen down the hill and gain back 0.5 miles. I may not have enough to get to work. If your commute is well within your EV range then that would be an easy way to do it. Of course, with practice and correct timing,, you can probably get close. But in my case, its not worth the trouble.

This morning I used the N method which worked fine. I had Torque running and put it in N when my SoC reached 83.9%. I actually only coasted like another 300 feet before I had to start slowing down for the Stop sign, but apparently for me, that 300 extra feet of regen made the difference between ICE start and no-start.

I was going to post the table from my Tuesday commute that shows my SoC and period of regen and when the ICE turns on, but using the table feature looks like a pain. So here's my log. Check out row 132 and the preceding few rows. You can see where I was regenerating and when the ICE came on (look at the RPM column). At row 143 is where I stopped at the stop sign - ~11 seconds later (the MPH doesnt show I stopped, its shows 2MPH, but trust me, I stopped, often times there's a cop there.. the speed logging is a little sluggish) The ICE shuts off at row 433 (301 rows later, each row is 1 second = 5 minutes).

http://www.tracksyde.com/forum/pip/torque_phv_20120320am.csv

The PiP charges to 85.1%. The Nissan allows you to charge up to 100%. So they provide the safer 80% option. The PiP has no choice, just max 85.1%.

Well, to be clear the Leaf doesn't charge to 100% either. Nissan has the MFD tell "white lies" about the state of charge.

the 100% and 80% are relative terms not absolute.

So the 100% on the Leaf might be close to the 85% on the PIP. You'd have to get into down and dirty specs and do a lot of math and arguing to get an accurate comparison.

But I do thank you for letting me know there is only one charge setting on the PIP.

While its not going to solve you problem, I though I'd share how the Volt solved this problem.. (details from What happens when the battery is full but you're decelerating in low?)

What a nice, provocative bunch of answers! Thanks all! I'm still puzzled by the "why" of the engine start during full-battery downhill: It seems that the ICE wants to run for a minute or so without allowing any connection to the outside world when it first starts running. That's more than enough time for me to finish my braking, so I suspect the engine is not supplying any braking whatsoever (it's just sitting at idle rpm during that first minute or so), but simply warming up. Obviously without a connection to the GPS the system doesn't know if you're starting to go down Pike's Peak with a full battery (in which case the automatic "B" mode would eventually become quite useful), or just coming to the bottom of the only hill (which means the start was totally unnecessary). I realize all this is kind of silly. A few tablespoons of gas is not important in a car that needs to use gas to go on most trips, and I'm quite happy to collect 80-100 mpg in general, but it's just fun sometimes to avoid the engine! I can see you Volt owners out there snickering. We tried the Volt, and it's a wonderful car, no question. It was just a bit too small for what we need in a car.

When you first start the car, the ICE runs for a minute in order to warm up, which reduces emissions.

When you go downhill with a full battery, the transmission spins the engine in order to slow the car, but the injectors squirt no gas into the engine. That is what the B mode does.

DO NOT put a car in Neutral when going down a long hill. You can overheat the brakes.

Somewhere I heard that it is against the vehicle code in California to shift a car into Neutral while moving (other than in an emergency, like a stuck throttle). True, a Prius (not just the PiP) is doing all sorts of things internally that have the same effect, but that doesn't count.

You're right, it is illegal:

V C Section 21710 Coasting Prohibited
21710. The driver of a motor vehicle when traveling on down grade upon any highway shall not coast with the gears of such vehicle in neutral.

Why? I think because the brakes can overheat, and you don't have control of the vehicle in a panic situation because you can't accelerate in a panic when you stomp on the gas. And the engine can stall (at least on older cars), leaving you without power or brakes.

How big of a hill are we talking? How any feet elevation loss ( and over what distance)?

is this strictly true in the PIP as well? i ask because i am seeing this behavior even when the car is started in EV mode.

i know on a gen2 prius with the EV button hack, if you put it in EV mode before the 7 second power-on timer expires, it will not fire up the ICE.

twice now when my PIP was cold, it started the ICE. the climate control was off, and the battery was full (car was plugged in overnight). backing out of my driveway, the ICE fired up.

given that the manual says it will start the engine if the car has gone XX days without running the ICE, it seems that something is wrong here and the car should not be starting the engine.

the pip engine should not start in ev mode unless you exceed the parameters such as throttle or climate control. if that happens, it will run thru the warm up cycle which depends on ambient air temp.

thanks, that's what i thought. i wish there was some feedback as to why the car decided to start the ICE. i guess i have to double check the climate control to make sure it's really off.

I'll let you know in a few weeks, when my ship comes in.

Waste perfectly good pads, when you can simply not charge to full?

.

Tracksyde, I like collecting data, but your file is tough to understand.

Mine has done the same thing, but even with AC, heat, and fan off. It has a full charge, and the HV had been used sooner then the 128 or so miles they say would cause the ICE to fire, so what's the cause? this is something we are all seeing, but it's still a dream machine

The ICE does NOT start when you start the PIP, as it does with the non-plug-in Prius, IF the Heater is off.

I drive only slight or short hills and the ICE stays off until I run out of battery, unless one of the following:

- If I step on the Gas and go into the Power mode, the ICE starts and stays on for its Warmup, even if I drop out of Power mode right away.

- If I hit 62 mph, the ICE starts and stays on for its Warmup, even if I reduce my speed right away.

- If I turn on the Heater or if I forget to turn it off from the night before, the ICE starts and stays on for its Warmup, even if I turn the Heater off right away.

As I've mentioned before, I wish the ICE would NOT go into Warmup, unless I want to keep the ICE on.

For those starting their day driving down a long, steep hill, Undercharging the battery would be the better answer, so that at the bottom of the hill the Regen charges the battery up to the normal 12.2 miles.

ukr2,

Try this one then:

http://www.tracksyde.com/forum/pip/torque_phv_20120320am.xls

The first one, the .CSV, is the log file as created by the Torque app. The GPS columns are blank due to some issue with the Android device I'm using.

I cleaned up the log a bit and cleaned up the formatting a bit and resaved as an Excel. Each Row is a separate log entry and log entries are created every 1 second. The time displayed on the far left is the correct "minute", but for some odd reason its missing the hour (which was 8AM). The other fields are in their relative units. Oh, and I highlighted the rows when the ICE was running.

Hope that helps

For those starting their day driving down a long, steep hill, Undercharging the battery would be the better answer, so that at the bottom of the hill the Regen charges the battery up to the normal 12.2 miles.[/QUOTE]


By the way what is the NORMAL traction battery charge? When I first got the PIP it charged to 13.1 then after two charges dropped to 12.6. I know temp will make a difference, but the drop from 13.1 to 12. something so soon seems to be permanent.