I have found EV-Assist mode to be extremely elusive and only available under certain circumstances (low RPM, flat road). It does not maintain my speed either. It's "fun" when I can get it to happen but I don't find it a dependable source of power. For me, it's kind of an "enhanced coasting" that only operates in the best of circumstances, is difficult to attain, and impossible to maintain for much time unless I'm on an open road by myself and don't care about losing acceleration.

 

It will first feel like the car has lost power because the ICE valves close and you see the green regen bars appear. The best description would be it feels like you've downshifted. Then as you slowly push on the accelerator to get rid of the regen bars and start showing assist bars, the car will feel smooth and quiet.

It is available under most circumstances in the city between 15 and 55mph. In my case there are times where it kicks in when I don't want it to as I'm trying to get the most efficient FE going up a hill while trying to maintain my speed. The roads here in Sacramento are anything but flat, and on my commute probably kick into EV-Assist at least 10-15 times in 1/2 mile to 1 mile distances each. The only time I can do it on the highway over 55mph is on a 2% or greater downhill drive. It will maintain your speed when you are at 35 or below. Anything over 35 and it will help to slow your rate of deceleration. I have a post here at GH back when I first got the car asking "What is the purpose of EV mode when it can't maintain your speed". I got the response "It's only a 20hp electric motor which was not made to maintain your speed, but slow your rate of deceleration while the ICE is using no fuel". I use it in conjunction with downhill slopes so I have good momentum to make it up the next incline. My speed goes from 45 to 38 back to 45 as I go down up and down the hills, all while in EV Assist. I can only imagine how much better EV-Assist works on flat roads.

 

Not straight answer - Yes in the seat as your wallet gets fatter and

Straight answer - usually I dont feel much going into EV mode - the mpg pegs at 100, the assist may read 0-4 white bars and the engine seems queter (with fewer explosions going on). Coming out of EV mode, I tend to feel a slight thump as the ICE reignites - also the MPG drops down from 100.

Also, I tend to avoid using assist or regen much at all if possible. To me, the regen is there to collect some of the "energy mistakes" I make when braking or rolling down hills. The assist is just getting paid back on some of the mistakes - the battery is the bank. Make fewer mistakes and less regen or assist are needed and FE goes up.

 

Maybe think of it this way, Gniel9 --

It's a 90 hp gas engine, which is very nice for running straight and level but less nice for acceleration. But why carry around a bunch of extra engine to handle accel better when all the rest of the time that capacity is a drag on fuel economy?

So, add a 20 hp electric engine that does two things: 1) cranks up on demand (you nail the gas, it comes on to Assist, white bars) when you need more horsepower for accel; and 2) adds a heavy-duty engine brake by converting coasting energy to electricity as you slow down (you hit the brakes or take your foot off the gas to coast, it turns into a generator to recharge the battery, green bars).

Now you have the best of several worlds: small displacement/horsepower for cruising, adequate acceleration despite the small engine, and recovery of ordinarily wasted energy during braking/coasting.

So, to your question of whether Assist is more economical, the reason the answers are mixed is this: If driven reasonably, most or all of your charging is "free" energy, and that free energy is given back during acceleration, so it's *more* economical when using Assist than an engine without assist would be. BUT, to be the most possible economical, you'd use less energy to begin with by accelerating more gently -- and in the HCH II, when you do this, you won't see as much Assist (fewer white bars) because there's less momentary energy demand and the gas engine can supply it. Most of us, I think, find that it's not a perfect world where we can fully charge the battery just with coasting/braking if we're really using max assist all the time. If you're constantly seeing lots of white bars (more than 4-5) when you accelerate, very likely the battery will deplete until the engine starts charging it whether you're braking or not. That's forced regen, and it's inefficient.

Maybe still too complicated? I dunno.
cheers --
doug

 

Well said! I like your description of mistakes, whether they are your fault or "traffic's fault," that's about the way it goes, and it's nice to have an economical way to regain some of the mistake.