Hello to all my fellow TCH owners. I have my TCH for about a month now. I love the FE of this car. However, what I don't understand is why the Electric Motor with 141hp @ 4500rpm, 199lb.ft @ 0-1500rpm (BTW these numbers don't mean a whole lot to me) is being used less than I expected.

Maybe someone can help me with the number above. My dead beat car from my colleage days probably have less HP than this TCH EM. What I am trying to say is... shouldn't the EM alone able to run the car for a short period under the speed limit? If so, why does the ICE seems to be doing most of the work, or coming on so quickly.

I have done two experiments...

The first experiment, from a quiet road, moving from rest to speed limit, under a slow acceleration (an acc. I wouldn't use on a main road ) after about 20km/hr or 12mph, the ICE always comes on.

Second experiment, when coasting on a level road, put just enough pressure to keep the EM on (to keep on a constant speed (60km/hr or 37mph)), but as soon as you wanted to accelerate slightly, or when you come to a slight grade where you can feel the car is slowing down, and you want to give a little more to keep that constant speed (no acceleration here), and the ICE always seems to come on in these situations.

I hope this is not just my TCH Can anyone confirm my findings?


The only comfort I have with the EM (that I know it is there and working) is when I back the car into the garage, there is a slight incline (shoulder) from the alley. I can feeeel the smoooothness of the EM pulling me in, instead of my old car with the ICE, where you give a little gas, and it jerks you in over the incline.

BTW... my FE average is 6.2L/100km or 38mpg.

Any thoughts anybody?

 

It's not a question of the capability of the electric motor, but the source of the electricity for the electric motor. The battery is only capable of providing enough electricity to produce about 30 to 45HP (somewhere in there, can't remember exactly) from the electric motor, anything beyond that is provided by electricity generated by the ICE. Don't think that because the ICE is running, the electric motor is not being used. In fact, much of the time the ICE is running it is generating electricity to operate the electric motor. The only time the car runs on battery alone is under very light power requirements where a gas engine tends to be very inefficient.

Under moderate power requirements the ICE will generate electricity for the electric motor (the electric motor provides more torque at low to mid speeds, since essentially the ICE direct connection to the wheels is in high gear all the time), possibly charge the battery (or the battery might be providing boost to drive the car depending on the situation), and provide some power direct to the wheels. This is where a lot of the fuel savings come from, where the computer is deciding when is the best time to charge the battery at times of higher ICE efficiency and use the battery for extra boost when ICE efficiency would be lower if it had to provide the extra power.

Under heavy load the ICE will provide maximum power to drive the car thru the electric motor and directly by gears to the wheels (the power split device, or aka CVT transmission will channel ICE power to both the generator and the wheels at the same time) along with available output from battery to electric motor to provide overall maximum power. That is why the total HP of the car is essentially the max output of the ICE + the max output of the battery and not the max HP of the ICE + max HP of the electric motor.

PS What you describe about your TCH is all perfectly normal operation.

 

Thanks Droid13,
I think you migh have shed some lights for me.
So the HV battery only provides enough juice for about 40 something HP? I kept thinking the capability of the EM (from the books it read 141hp). That would explains it.

 

You'll get the hang of it by experimenting with pressure on the gas pedal. When I turn off the main road (a 55mph limit) to my development the TCH always turns off the ICE as I slow down and make the turn. Then I've learned how to keep a slight and steady pressure on the pedal (I can get it up to about 20-25 mph, but theoretically I think you can go as fast as 39-40) to keep it in E mode the 2.5 blocks to my driveway and into the garage. I'm only going a little slower than I normally have and I get a nice, quiet, relaxing 'coast' to home. I love this car.

 

Theoretically you can coast with EV up to 42mph.
I am regularly able to get it to about 40-41mph.

BUT, since the speedometer on the TCH reads 3mph over what you are actually going, I guess I max out at 38. In this respect, I wish the speedometer was calibrated properly so I could get the extra 3mph out of the EV.

 

Is there any way to adjust the "sensitivity" before the ICE engages?

In stop an go traffic, sometimes I can keep in E mode for quite a while, but other days it keeps kicking the ICE in (even with a full battery). it's sooo sensitive, just a little too much pressure and poof, I'm burning gas for no reason (I'm stopping if a few feet)

I'd really like to be able to push the gas peddle with a little more pressure, before kicking out of E mode...

-Steve

 

How cold the engine is, how cold the cat is and the temperature and SOC of the battery determines how easily the engine comes on to power the car.

 

The engine is usually warmed up by the time I get to any real traffic.

I really wish there was a button I could press that made it just stay electric mode until it needs to charge the battery. I know I'm in bumper to bumper and no matter how hard I press the accelerator, I'm just going to stop in a few seconds...


-Steve

 

I Know what everyone is saying. But stevesreed is more on the same page as I am.
I know how to coast too @ 60km/hr (or 40mph) on E mode. But have you try to nudge it to 70km/hr (or 44mph)... in a timely manner (like within 45 to 60 seconds), just to let you know I am not trying to push it hard. Or how about keep coasting onto a incline 1% ~ 2% grade. The ICE will always comes on.

From what I understand from Droid13... the EM only have 40'ish hp. I don't really know what 40hp can do. But it seems like it is only good enough to counter air resistance!

- ACE

 

Tideland Prius, Why are you taking your cat with you and what effect does "how cold it is" have any bearing on the operation in EV mode? I prefer taking my dog!!

I regularly can operate on my last 1.5 miles to home in EV mode by slowly accelerating up to 42 mph on a flat or slight downgrade and slowing down to as low as 30 on slight inclines. As long as the engine and emisions are all warmed up it this works pretty easy. Always a great chance to bring my FE up