Enginer PHEV Test Pilots: Mpg reports and important data

It's interesting that Joanna is getting much better mileage than MJFrog.

@MJ, when are you using your manual EV mode switch, all the time or no? I assume that when the ICE fires up you're kicked out of EV mode and you turn it back on every time you enter the glide phase. Is that right? How does the kit's EV mode work, anyway?

 

Not to belabor the point, but a ScanGauge could be pretty helpfully for the Prius II Enginer.us guys. It will give a few pieces of key data about the OEM battery that should be useful in maximizing use of the extra battery.

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When I start my morning commute, I turn EV mode on long enough to back out of the driveway and drive to the first stop sign...about 300 feet @10-15mph. I then turn it off so the ICE can go through warm-up. I have two more stop signs and a median turn-around before I reach the 45 mph road I travel on. If the ICE does not auto shut-off at those stops, I'll use the EV button to force it off (if possible). After that, I don't use it unless I am caught at a light and need to force the engine off there. Depending on my SOC (e.g. all-green) when I get close to work (3-4 blocks), I may turn EV on again.

During my trip home (another route) I normally don't use the EV mode at all. See this post.

Not sure since I asked Jack not to hook the kit's connectors up so I could control it myself.

 

Perhaps you could try staying in normal prius mode until you hit the 45 mph stretch and then go into EV mode and stay there until your PHEV kit is depleted - of course you'll get kicked out of EV mode if you accelerate hard but you can reengage it once the acceleration is over. You might get better numbers that way. (And turn the kit off if you're about to climb and descend a sizable hill, making head space in the stock battery for the downslope regen).

I suspect that the enginer kit regularly sends an EV mode "on" signal to the Prius to keep the car in EV mode as much as possible. Once the kit is turned off, this of course stops.

Did Jack give you any tips as to how to manually utilize EV mode?

I think it's better to be in EV mode with this kit as you can accelerate by all electric at a slightly larger rate when in EV mode.

Of course the main reason you don't match Jo's FE numbers is probably because you have a 2kWh pack and she has a 4.

 

For all intents an purposes, except for the 300 ft jog down to the first stop sign, I AM in normal Prius mode. I just use the EV button to force the ICE off at the stop signs if it doesn't stop automatically. When I pull out from the stop signs I turn EV mode off.

No

I'm going to disagree. The ICE is more efficient at accelerating than the electric motor.

Agreed...mostly.

 

If and when all the energy is coming from the gasoline (stock Prius) then yes do not ever accelerate in EV mode. ever.

That's basic physics - always avoid conversion losses.

But given that you have sourced energy from the grid, use that as much as you can, instead of gas until the pack runs dry - that would be my recommendation.

 

Ahh Ha! If your ICE isn't off when you approach a stop sign, your engine is too cold. Below a thermal threshold the HSD is only partially enabled. This is all part of the "5 stages of Prius operation" paper. Even after the Prius warms up, the HSD won't go fully enabled (some times ever) unless you have a specific transition that happens when your at a stop.

May sound like a bit of work, but a engine block heater and knowing how to force S4 (the 5th stage of the 5 stages) may double your MPG overnight, especially with a PHEV mod installed.

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I haven't studied the 5 stages paper myself. Never needed to learn how to get to S4 as my Prius is never running the ICE at a stop after the first few minutes of operation. Maybe it's the mild climate I live in. Not too hot, not too cold.

Sometimes, rarely, I appear to be out of S4 when I'm moving, because the ICE comes on even when I'm trying to glide, but I believe that's because the ICE has become too cold after a long series of glides/coasting.

 

Unlike other conversion method, the Enginer kit is designed to run under blended mode instead of pure EV mode. You usually use ICE to accelerate and use EV to stay in cruise speed under 45 MPH. Using OEM battery to accelerate would deplete it quickly and Enginer kit has only 3000W throughput to recharge it. The technique is simple, releasing the throttle and re-engage it softly. I believe the motor control is pressure based and the ICE control is position based. You can press the throttle hard enough to get the desired speed and soft enough not to trigger the ICE after warm up period. It needs a little bit practice but it is not that difficult.

 

Ok so I was wrong. Still use gas to accelerate at the normal rate.

Use EV to maintain speed or for small accelerations.

That's to glide after pulsing.

This last statement confuses me. It sounds like you're describing how to accelerate with out triggering the ICE which is something I thought you didn't recommend.

And what about the kit's ability to invoke EV mode in the Prius. How does it normally do that, how often and when?

 

Exactly. I was describing behaviour when I start my commute. I've noted elsewhere that I'm not completely warmed up for 4-5 miles (6-7 lately because it's getting cold). However, once past the 57 sec initial ICE run, I can force the ICE off while I'm STOPPED at the STOP SIGN...to not waste gas. I exit EV mode when I take-off again to continue warm-up.

I definitely would if I could afford it (maybe I can't afford not to?).

 

Using B doesn't increase regen compared to coasting/braking. Only use B to spare the brakes on an long down hill slope.

Have you done aby manual tank calculations yet to determine your real FE - since your MFD is unable to display above 99.9?

Being in Canada, I expect I'll benefit from having my display in L/100km.

 

That's strange for this time of year. My car almost year round will light the ICE for a minute and it virtually never comes on again when I am stopped - all on its own.

An EBH is fairly cheap - parts and labour only cost me $180 at the local Toyota dealer. It helps reduce warm up even in the summer believe it or not

 

It's 102F in Houston and my engine takes about 20 minutes to hit 70c (but I spend most of those 20 mins with the engine off). Any drive under 20 minutes and I have no hope of hitting S4. I simply smash the EV button EVERY time my foot comes off the gas. Problem solved.

Install isn't that hard. Frankly I wouldn't trust a mechanic in Houston to do it, so I did it myself. Houston has few requests for EBH installs as you'd image. For Toyota's all you have to do is stick a metal shaft in a round whole. Sure that whole is hard to get to, and prone to scratch you up pretty good on the way, but mechanically it's fairly simple. The parts cost $50, and I spent 3 hours doing the install.

If you get stuck call me and I can walk you through the install.

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09/01/09 morning commute:
MPG per MFD: 68.4
Road conditions: dry
OAT: 48-53 F

Left balancer readings:
High cell: 3.285
Dif b/t High/Low: .016
Voltage: 26.22

Right balancer:
High cell: 3.288
Dif b/t High/Low: .030
Voltage: 26.16

Comments: OAT about the same as yesterday...got to get that grill block installed to improve warm-up. Probably block just the top for now. MPG still improving in spite of the cool mornings. Either I'm learning to drive on the pack better, or the pack is breaking-in more...probably both.

Yesterday evening I took the wife out for dinner. Temps in the low 70s. MPG on the way to the restaurant was 63.5...and it was a mild uphill climb over 7.9 miles (maybe 30' elevation). The trip back I got 74.9 mpg...and for a while the MFD read over 75.3 mpg. It will be interesting to see my mpg on this tank when it comes time to fill it.

A note on charging... When the charger shuts off, the left balancer frequently indicates cells #7 and #8 are high--they read between 3.760 and 3.840. I sometimes get a high cell reading on the right balancer (#7 cell)...around 3.790 last time.

 

The Gen III using ECO mode has a very convenient line on the display for doing just that....

 

Yeah, that's ironic isn't it. The better your mpg and the more you want to check it, the longer it is before you need to refill.