Near-Production Honda CR-Z Shown Off, Looks H-O-T

I suspect our visitor has moved on and won't be following the thread. But I'd like to suggest another description (borrowing a Hobbit phrase) that more precisely describes the Continuously Variable Transmission (CVT.)

The Toyota and Ford CVTs have a fixed set of gears and one Power Split Device (PSD.) Both have two motor generators of which one, the "generator" or what we call MG1, is connected as the 3d input/output to the Power Split Device. The other two are the engine shaft and the drive to the gears leading to the differential and wheels. There is a second, more powerful motor generator we call MG2, that is equally important but in an unexpected way. The magic happens in the Power Split Device that looks like a planetary gear with the engine shaft, MG1 shaft, and output shaft (aka., ring gear) to the drive gears.

MG1 and the engine are in an eternal torque struggle whose output drives the wheel gears. About 1/3d of the power comes from MG1 or is driven into MG1 to provide the counter torque against the engine. But that means MG1 has to either generate or sink a significant amount of power, which it does with MG2. Except for transient states, the batteries are 'passive' compared to the ICE vs. MG1 torque struggle and about 1/3d power flows between MG1 and MG2.

This 1/3d power is "split" and actually travels across an electrical circuit around the power split device and between MG1 and MG2. Without it, MG1 could not generate the torque needed to balance the engine torque. Fortunately, this electrical power is completely controlled by the computer driving the power electronics, the inverter.

As a driver, we provide inputs to the accelerator pedal and these signals (there are two,) tell the control computer how much power we want. The computer then coordinates the engine control computer and inverter to manage MG1 and ICE torque. This 1/3d power is looped to or from MG2 so the energy losses are MG1-MG2 electrical and that applies only against the 1/3d that takes that path.

It is not a simple system to learn and even now, it can lead to a headache ... and we're Prius people. For 'guests', it is such a foreign concept that I seriously doubt they ever really 'get it.' But Hobbit's description sometime back about an eternal struggle between the ICE and MG1 helped me more fully understand what is going on ... as well as looking at a lot of Graham Davis Miniscanner data.

I left off the part about the Atkinson cycle engine as it has a different area of importance. The CVT does not care what cycle the engine uses.

Bob Wilson

 

Very informative post until the above paragraph.

Wow, Prius people are really superior after all.

 

Damn! That thing is EXTREMELY hot!

I can't wait to start seeing them on the street and of course it'll be nice if they sell really well.... which they will. ;-)

 

I considered waiting for a CR-Z rather than buying a Gen 3 Prius until I learned that Honda discontinued their plans to make the CR-Z as a non-hybrid. (I don't care much for Honda's hybrid system, especially how the ICE turns off immediately at a stop sign and then restarts as soon as you touch the gas pedal.)

I would have loved to purchase a non-hybrid fuel efficient CRZ that would be similar to the CRX HF I had with tall gearing, skinny tires, low weight, manual trans, and the great styling it has. But it seems Honda will only make the CRZ in the CRX Si sporty format and not offer the HF fuel efficient format.

 

Body style is nice, looks sporty.

Honda really has a chance to make something great.

A really refined i-CVT with a high/Low electronic final drive ratio selection. Low for sport driving when your in the mood, and a high ratio when you are feeling greener and gas milage is more of a concern.

An adjustable suspension, soft and comfy, adjustable to a firm and sporty would be a nice dual purpose vehical.

and It must be a Hatchback. I will not own another car without a hatchback. Too much usability lost.

I' am waiting for Toyota to make the Yaris into a i-Cvt Hybrid.

Dont get me wrong, I really like my 2010 Prius all the tech. is great, But these car companies have spent the money on R&D the tech is proven now use it, use it on eveything. Either this prius drive train would make a Yaris a very sporty little 3 door hatchback that would get great milage, or use the privious edition Prius drivetrain.

Just my 2 cents

Westgl

 

"Tokyo Motor Show. And now, at this year’s show, Honda has revealed a new CR-Z, a 2-seat hybrid sports coupe that looks very much like the final production version scheduled to go on sale in the U.S. in the second half of 2010."

"the production CR-Z (which makes its worldwide debut at the North American International Auto Show in Detroit in January)"

"With the CR-Z—which goes into production at Honda’s Suzuka factory in February"

2011 Honda CR-Z- Yahoo! Autos Article Page

.