I wanted to impressions of the acceleration characteristics of this car.

What I have found is if the car is already moving, pressing firmly on the accelerator, will accelerate the car quickly. Plenty of giddy-up for merging on to a highway, or passing.

However if stopped at a light, pressing firmly on the accelerator, will incur a bit of a stumble, before moving. Actually something like move, stumble move. Not bad, but certainly noticeable.

I'm thinking that with the electric motor produces all of its torque at very low rpms, that I should even be able to light up the tires, if I wanted.

Thanks, Ben

 

My theory is that hybrid vehicles are programmed to offer a slow startup to give you a chance to reconsider if you really want to accelerate at an unnecessary rate of acceleration. I have noticed this in my wife's HCHII and also in our work "truck" the FEH-II (2008). This could be contributed to the CVT also, with programming to limit the torque going in. The only hybrid I have driven that does not display this behavior is my HAH. When I floor it the only thing that interferes is the traction control because without it, the tires would be reduced to a pile of ash.

 

Noticed the same thing, but only when the ICE shuts down. I'm supposing that it's the ICE starting. When the mileage display is at '0', there is no stumble; when it's in the 'e-zone', there is a slight stumble. Kinda reminds me of an old Rambler I had before I managed to tweak the accelerator pump and initial spark advance to make it go away.

 

I would describe it as running over a stick when you start. Sometimes this can be annoying if you have several passengers in the car driving in a neighborhood with repeating stop signs and speed bumps. The ICE starting and stopping over and over and over again.

I discovered a trick to prevent this. Move the car to the shift lever to “B” mode. The ICE will remain running during each stop until you move it back to drive “D”.

I have a close friend who lives in a neighborhood that has the repeating stop signs and speed bumps.
I hope this helps…


Bill

 

Thats a great tip, which I'll try. It wasn't so much of an annoyance for me as compared to an expectation. I'm thinking with electric motor with all the torque down low, it would be a stump puller and not 'stumble'.
I can overlook that for mid 30's mpg...

 

Well yes the electric motor will produce 100% torque at low RPMs, but, it is also only 40 HP so if you stomp on the gas you will hit its threshold and the ICE will start, during the ICE start it clearly needs to briefly disengage the gears (or something of a more technical nature) to prevent a jerk and lurch.

It is sort of annoying if you have to stop at a yield and need to quickly pull out in traffic. Of course this can be solved by not trying to pull out with such little time!

 

During the summer I have found many times when at a red light in town. I can ease on the accelerator and still keep the car in the EV mode. I found once the engine is at operating temperature. The battery is about 60% to 80% charged then the car takes off in the EV mode ever time. The engine also shuts off as I coast a good ways to the light. If I take off fast at all the ice kicks on and shares the electric motor to accelerate.

I have found my best acceleration if you are accelerating at 10 or 15 miles per hour then take it to the floor. I never had a car that would pass another car like this one when out on the highway. It's fast for sure.

 

While it's a 'stumble' (best way to describe it), the truth of the matter is, with the exception of the way it feels to the driver, it's only a momentary thing. Within a half a second (more or less) the car gets into 'normal' acceleration. Your occupants might not notice it, the other cars on the road wont notice it. If you accept that this is how the car handles quick accelerations, it wont bother you...just get used to it.
If you need to do very quick accelerations, the car will accelerate (although I'd advise against using it for drag races).
If you are at a stop sign and need to gun it to get onto a fast moving lane (...I'd say to wait a few seconds of find another route, but I tend to drive very defensively...), just gun it, the car will respond. If the 1/4 second is the margin of safety, then you are probably putting yourself and others in a lot of danger and really should wait for a better time to proceed, plan another route or wait for a better time to proceed. (IMHO)
In any event, if you gun it, the car will move.
Just get used to the stumble and it wont bother you.

 

The electric motors are each over 50 HP, but usually one is working as a generator, supplying power to the other one acting as a motor. (MG1 generating power for MG2 is equivalent to low gear, where MG2 generating power for MG1 is equivalent to high gear or overdrive - the electric motors are the car's transmission, as well as other things such as the starter and battery generator.) The drive battery can provide over 40 HP of current to the motors which can add to the ICE power.

To start up the ICE requires about 1 HP from the drive battery, so starting from a stop with the ICE off gives you about 40 HP of acceleration for a moment until the computer decides to start the engine, when you get about 39 HP worth of acceleration for about a second while the ICE starts, and then you get additional power from the ICE which gradually builds as the ICE speeds up for about a second to give you up to nearly 200 HP. That full power is only available for a few 10s of seconds until the battery charge goes down and then only the ICE power is driving the car.

I'm guessing the reported startup "stumble" is going from (about) 40 HP nearly instantly, down to 39 HP for about a second, to over 100 HP all within a couple seconds, where a non-hybrid conventional vehicle starting with the ICE already running has a longer delay to get the ICE spun up to less than 40 HP, but rapidly increases to over 100 HP. Both systems will likely cross that 100 HP on their way to full power about the same time, but the hybrid will give more power initially (thus better 0-60 MPH times for equivalent weight vehicles for a hybrid with less total ICE+battery HP than a non hybrid with more total ICE HP).

Once the ICE is into it's power range, the hybrid power will be perfectly smooth regardless of the vehicle speed or acceleration, while the non-hybrid must suffer those horrible, stumbling, intermittent losses of power and efficiency during those antiquated events known as "gear shifts".

-- Alan

 

Yeah, I got the 40 HP number from Toyota's site and my paperwork from when I purchased the car. If I remember correctly, the total HP is 192.

I thoroughly enjoyed your description of "gear shifts" .... it was a good read Alan!