hi all!
When stopped at a red light, the TCH is in EV mode. If I am going to make a right-on-red (legal in NJ), I notice that after accelerating ever so slightly, the ICE starts up and runs for a bit, in the middle of the turn.

My questions are:

1) is this normal? (not turning on red, but the ICE starting up)
2) if it is normal, does the hybrid battery level have ANY affect as to whether the ICE starts up when accelerating in EV mode?
3)I'm pretty sure that when in EV mode, going straight, on a level road, without turning the steering wheel, the TCH stays in EV mode, up until appx. 39 mph. It takes a while to reach 39 mph with an extremely light foot on the pedal, but it can be done and. yes, we still have some roads in NJ without traffic!)

Once i accelerate a bit, the ICE kicks in, irrespective of hybrid battery level.

Another but related question... why is there a 3mph difference between the speedometer and the GPS speed(from diagnostic mode). GPS speed is confirmed by my scangauge II, but my speedo registers 3 mph higher.

All comments are welcome!

 

I'll answer your last question. The difference between the speedometer reading and the actual speed is mandated by U.N. regulations. Someone in this forum posted a copy of the reg several months ago. I, for one, am glad the U.N. is looking out for us, making sure we don't actually go the speed limit.

 

I've ony had my TCH for 2 1/2 days now, but I did notice that the ICE had started a few times when I was making a turn. I think it all depends on the turn that you are making. Whether its uphill or downhill, if you are accellerating or just coasting.

What I have noticed is that you can let up off the gas pedal on a flat road when the ICE is on to shut it off and then maintain that speed in ev mode only.

One other thing that I've seen is that there is a delay of about 1 sec when the ICE comes on and the MFD shows that it has done so.

 

I find with the A/C on it is more difficult to stay in EV mode.

Turn your a/c off and see if it stays in EV longer.

 

Electric motor can develop more than 100 HP, but the battery is limited in it's output to some lower number which at the moment escapes me. Therefore , depending on the throttle position the computer will decide at what point it needs ICE to start , to help the battery. Getting going from dead stop is usually high current affair and ICE will come on most of the time, especially during the turn which requires more effort than straight line acceleration.
Fully charged battery can provide higher amperage than lower charged battery: To begin with fully charged cell will have higher voltage and higher voltage will provide higher amperage (everything else being equal) and power is voltage multiply amperage. Anyway:
1. yes, it's normal
2. Ohm laws, see above plus possibly some other things like temperature, computer programing
3. EV limit is about 42-43 MPH indicated, but you can run electric only at higher speed, the engine will spin but injectors are cut off from delivering fuel. The reason for the limit is that at higher speed with ICE stationary electric motor that starts ICE runs at too high speed and would have problem to crank the ICE if it was required for more power.
As he said, the indicated speed is higher per agreement by about 2-3 miles (but only above 20 MPH, believe it or not bellow 20 MPH the speed is correct). One reason for the agreement I can think off is simple: No instrument is exact, especially mass produced and being used for 5-10 years so if you start on the high side there is very little chance to show the speed lower than actual and if the speedo was showing lower than actual I can see the lawsuits coming with every accident where speeding is a factor. Here, the speedometer shows higher speed than actual, so there is no excuse if you get a ticket or wipe out, fault is yours not the car.

 

Could be that in a turn with any acceleration at all. The engine sees enough load to kick on the ice. It may be possible the electric steering needed some engine assist in the city turn you spoke about. I don't know yet if this electric steering is all by itself or it can still switch or share with the hydraulic pump. I will try to ask a toyota mechanic this week when my new TCH arrives.

 

I am not an expert so I can not answer your questions. However, I will share my experiences here about EV mode.

1. When starting from complete stop (zero speed) ICE usually turns-on unless engine is really warm and you start very slowly with very gentle pressure on GAS and of course not going up again any amount of slope.

2. I have also experienced ICE turning on more while taking turns.

3. While costing if you hit any bumps usually ICE turns on and giving up gas pedal for fraction of second puts it in EV mode again.

4. With AC off, my TCH will normally go in EV mode after I accellarate close to 60 KMH and then giving up gas for fraction of second. Weired thing here is that if AC is OFF and if I try to give up gas after reaching 50 KMH I may not get in EV mode. With AC on I can get in EV mode after accellarating just over 50 KMH. In short with AC off it needs over close to 60 KMH and with AC on it needs around 50 KMH. I am not sure why.

5. Instead of maintaining maximum speed in EV mode (in my case 60 KMH) for longer period/distance, I found that slowing down little bit whenever you get a chance helps in maintaining battery in better charge thus giving over all longer distance in EV mode.

These are few of the thing which I experice in every city trips.

Thanks

 

It is normal for the ICE to start up on normal acceleration. You want the ICE to start unless you will just be costing to the next stop or cruising a parking lot; otherwise more fuel will be used to recharge the battery than would have been used to accelerate.

Yes, if the SOC is high, the TCH will allow more acceleration in EV mode. If the SOC is too low (under three bars), any acceleration will start the ICE.

I find I get better mpg if I accelerate normally (using the ICE) and then maintain speed with EV mode, than taking a half mile or so to come up to speed using only EV mode.

Tip: After the car is warmed up - allow the car to stop with the ICE idling (if necessary, press the gas pedal while holding the brake pedal down to start the ICE) and let it "shut off". It will take 8 to 10 seconds. After the ICE shuts off at a stop, the hybrid system switches to full mode and freely switches to EV mode anytime you coast at any speed under 40mph. I find it easier to "start" the ICE while coming to a stop by shifting to "B" around 25mph. Don't forget to shift back to "D" after stopping or the ICE will not shut off.

 

Yeah, the tip by nash is one that's made me much happier, I have to admit.

I will also point out just from a pure physics standpoint, making a turn means you're literally _accelerating_ toward the center of the curve (by which I mean the center of the circle you'd make if you kept turning for 360 degrees). And obviously if you're accelerating for the turn, and trying to accelerate just in terms of your speed, that's more accelerating you have to put the car through, so it makes sense it would require extra power and could kick the ICE in.

 

chestr — I have to disagree! You are indeed accelerating when you go around a corner, but no work is actually being done (your kinetic energy stays the same), and so no extra power is needed in principle. In practice, however, I think that you do tend to lose some energy "around the bend" due to rolling resistance losses in the tires and losses in the differential. This might explain it.

Stan