Living on top of a hill

200 MPG from a plug-in hybrid is frustrating?

What were your expectations?

 

Hehee, I hear you.

We are an edge/unusual case. We generally do three drives each day. Since we live in a city that is 5 miles across, and bordered by water on three sides, almost 100% of our drives are less than 10 miles round trip. We do on average 3 of these drives per day.

What I was shopping for was an EV that had a range of 10 miles and wouldn't break the bank. The Prius Plug-in seemed perfect- It could run on EV for 10 miles 3 times per day, and its small battery meant we could easily recharge quickly in between. Plus it removed our "trip car" from the budget (for going to Yosemite or wherever). It's also just a really refined car because Toyota has had so many years to perfect their systems...vs. some of the competitors which seem pretty "beta". Also, since battery tech is the thing most likely to decrease dramatically in cost, it seemed unwise to spend a lot of money on a very large battery when we didn't need the range.

I did quite a bit of research and analysis spreadsheets before the purchase; and everything is *mostly* working out to expectations. The problem is with this extra engine start that happens because the battery has *too much* energy. I wasn't expecting to have to factor in 3 of those most days. Even though it's only 4 ounces each...it adds up quickly at 3 times per day. We are coming up with solutions though; so I'm not worried. Mostly I just don't like polluting with burning gas just to warm up the engine -- it's the principle.

Both my wife and I are EXTREMELY pleased with our PiP. We're just learning some of the nuances of EV driving -- like where do you put regen power from a massive hill when your "tank is full".

As an aside; I grew up in Wisconsin...so I'm guessing your driving patterns in Minnesota are dramatically different from mine

 

I've been running into this problem lately and had overlooked this thread. The past two mornings I've shifted into N and coasted about a 1/4 to a 1/2 mile downhill. Once beyond the lowest point of elevation and my speed drops to around 35mph, I transition back to D. Each time, that transition has caused the engine to kick on and it's a less than ideal situation to have the engine running, as I could otherwise go all EV for another 3/4 of a mile before switching to HV mode for a long and rather steep uphill climb.

I've got a stretch of 200-250' coming out of the driveway that requires slight motive force, but the remainder is all downhill out of our development, followed by the afforementioned costing stretch. Perhaps the spin up from N to D causes too much regenerative flow to the pack and sparks the engine?

I realize it's somewhat trivial but inquiring minds have to know. Any thoughts?

 

Until I can build a more high tech solution, I'm driving UP the hill (opposite direction I want to go) for about a block (very steep). This burns through enough energy that the engine doesn't seem to cut in on the downhill. The waste of electricity is less costly and cleaner than the 4oz of wasted gas and it doesn't really add much to drive time.

Alternately, some days I use the neutral trick. However, I don't like burning up my brakes.

 

I've had this happen before too. But I come to a Stop sign at the bottom of the hill so if I just wait until I'm stopped, it's fine. What I experimented with a little before was accelerating at the top of the hill on the way down. That gave me a bit more time to burn off some extra charge. I'd pick up a bit more speed than normal, so that would also force the use of the friction brakes more.

My guess is by the time you start descending down the hill, you're still over 84% SoC (only down slightly from the 85% full). So after a short trip down the hill, any regeneration will trigger the ICE to start its warm-up.

Can you drive around the block once to burn off some extra charge? If you can get your SoC under that 84% range before you start down hill, I suspect you wouldnt have this issue, following your current procedure.

 

Tomorrow I'll try a different route out of the development and keep a close eye on the 85% SOC. I should have been keeping a closer eye on the SOC read out on my ScangaugeII to determine the point at which the engine is forced on. Thanks Tracksyde!

 

I tried watching SOC for 85% and oops.... too late... the ICE went on. The gauge doesn't update often enough or I'm not quick enough. I'll stick to using neutral for the short distance required on my downhill route.

 

The ICE should start at about 84% SoC. A full charge should be around 85% SoC (I've seen 85.3 to 84.7 using Torque).

On my way to work, I get down to about 83.3-83.7% or so after leaving the house and reaching the downhill portion. That's when I start coasting (regen). Once it hits 83.9%, I usually wait a few more seconds before putting it in N. But from what I've seen, once it hits 84% or so, the ICE will start.

 

Just posted in another thread about this problem. I charge at work (on a hill) and have to drive down the hill after a full charge. Would always switch the car to N to avoid turning on the ICE, but recently discovered that turning on the AC and fan at full power allows the car to accept more charge (above 85% soc based on SG2 readings).

 

Thanks for the tip!

 

This is a great idea! I wonder if JUST cranking the fan will do it. I notice the fan brings down the miles available right away when turned on even without AC and climate set to LO.

 

Try testing. I did try turning the fan on low with ac on and it didn't stop the ICE from turning on. I had to have the fan on high. Hope other ppl can test it out as well. I have a scan gauge and the SOC reading was 87% at the bottom of the hill where I work, and the ICE did not turn on.

 

Would turning on the headlights, perhaps on produce the same result?

 

Could be.. but it could also piss off quite a few ppl IMO.

 

At 6:30 am (sunrise was at 5:30), on a city street with virtually no traffic... shouldn't be a problem. If "highs" work maybe "lows" will work too. Better than using friction brakes to keep the ICE off.

 

It didn't work for me. I had the fan, A/C AND headlights on. The SOC got up to 85.4% which is what it often shows after the nighttime charging. Then the ICE turned on. So its back to using Neutral for me.

 

Yeah, I can confirm that nothing seems foolproof on this point. Neutral is not an option for me with a 750 ft drop in 2 miles. One thing I have done if I hit the red light on the bottom is turn the POWER off; the restart delays the ICE. But to be honest I have stopped worrying about it. The overall effect on total MPG is quite small.

 

Strange I easily get SOC up to 86% with no issues. I do not shut off the A/C until I hit the final red light at the bottom of the hill. No ICE.

I am going down the hill in D mode, not B. Just using break pedal to slow.

 

It worked for me. I have a steep down hill. I was placing the car in neutral to prevent the ICE turning on. I have suceessfully used Chesleyn's technique three days in a row. I usually make it 1/3 of the way down before the engine triggers. As the EV range indicators reached the maximum level I turned the fan to high the drops by a 1 to 1.2 miles. It climbs higher as I descend. At the bottom of the hill I turn off the fan the estimated EV bounces backup. Using this technique I typically gain .2 estimated EV.

Thanks Chesleyn's!

 

I wrote a different post here to see about implementing the "city" mode for our USA cars. I was looking for schematics or guidance on how to do it - however, never got anywhere with it.