Yesterday, we were stuck on the Garden State Parkway until we passed the cause of the traffic jam - an accident. It took 45 minutes to go appx 6 miles. During this time, I was able to observe the following:
We went into EV mode as we were in stop-n-go traffic. SOC initially was blue, i think it was appx 6 bars. Everything was great until the SOC went purple after appx 8 minutes(understandable as AC was on in ECO mode full blast). At that point, ICE kicked in and started running at appx 1000 rpm(ScanGauge). I figured that ICE would recharge the battery until SOC went into green, and then continue back in EV mode until SOC went back into purple. That didn't happen. ICE ran at appx 1000 rpm for most of the 45 minutes! SOC never went above 3 bars. FE went from 42 mpg to about 35 mpg. Could it be that toyota figured that running the ICE at 1000 rpm continuously to minimally recharge the batteries would use less fuel than if ICE ran at a higher RPM for a shorter duration while recharging the batteries until a green SOC is achieved and then running in EV mode until SOC went back into purple range and then repeating this recharge cycle as necessary? At appx 6-10 mph in stop-n-go traffic, there was minimal brake regen, so that did not help. I look forward to your comments/suggestions.

 

I don't have scan gauge, but it seems the biggest charge current you can get is from wheels, either during regen breaking or just rolling down the highway without demanding power. It seems to me ICE itself has much lower charging capability and with full blast AC, break lights and probably engine fan it may as well be that the battery itself didn't get much current to recharge.

 

nyceshirtz — You may be correct in your explanation. The electric air conditioning compressor is powered by the NiMH battery, and can draw a peak power of 6.1 kW (~8.2 hp) according to the manuals. I don't know what fraction of that you were using in ECO mode, but it would have been significant.

Stan

 

The TCH stops regenerative braking around 6MPH or so. The friction brakes take over at the lowest speeds.

A hint for stop and go. For any car. Don't brake. If people are accelerating to 40 and then stopping, run a constant 20 or so. You want to meet up the with stopped car in front of you as he is accelerating back up to speed. Keep a constant speed.

Even with regenerative braking, you are only getting about 50% of your energy back. Converting energy from gas to heat to kinetic energy back to electric energy and then back to kinetic energy has a lot of conversion "taxes" involved.

 

Hello,

I find there is not much that can be done about New Jersey traffic jams.

I was stuck on US-9 because Englishtown's speedway/auction traffic was spilling out on to Texas Rd. just this morning.

I have an Altima Hybrid and what I notice is after you sit in traffic to the point the engine comes on to charge, it seems to stay on until you can get the charge to the upper third of the meter. (The Altima has a needle gage not bars) EV mode may or may not come on depending on other factors. You may have to accelerate past 40 MPH at least once but this does not seem consistent and may be hard to do in bumper to bumper.

I have had this happen on US-1 and RT-18 many times so I feel your pain.

 

Hi. My Prius 2 did the same in a traffic jam this summer. The key factor was the air conditioning. If it's running without the ICE, it'll run the battery down until you're essentially creeping along with a gas-powered air conditioner.
Still, you're using less gas to do it than the SUV next to you.

 

Yeah moderately heavy traffic is _great_ for FE (in my experience), but severe traffic kills it. If traffic's thick enough that everyone's going 30-40 on the interstate, I can get great mileage cruising along like that, but when traffic stops... You're saving power while you're stopped, and using EV mode as you creep forward every so often, until the battery is so low the ICE kicks in. I rarely use AC but I don't know if I've ever seen the engine recharge the battery enough to even notice it when it comes on solely for low battery. Only thing I find I can do is try to avoid it happening by starting to wait until there's enough space between me and the next car to use some gas while I accelerate even the pretty small distance and stop using battery for every foot I drive. Lets me continue to avoid using gas to go 0 miles (which pretty well ruins your mileage), by not idling when I'm stopped. That's about the only solution I've found (except my new mode of skipping the heaviest parts of the nearby interstates on my commute lately--and getting low-mid 40s since I started going cross-country instead!).

 

Been trying this, but don't know where you live but in North Carolina when you do that, it means the guy next to you lane changes in front of you, slams on brakes, causing you to brake more, into some psychotic cycle of idiocy of lane changes.