got it. my only point was that getting into electric-only mode on the hch.ii is not difficult. simply drive the car and it will enter and exit ev-mode on its own whenever it needs to. no different than the prius here. however, i do agree that getting the hch.ii to start from a start in electric only is not only difficult, it is impossible.

regarding "full hybrids": starting from a stop in electric-only mode is not a requirement for full hybrids. i think what you mean is that toyota's hsd is a series hybrid system (as well as a parallel system) whereas honda's ima system is a parallel hybrid system only. you can have a "full hybrid" using either a series or a parallel system.

 

The commonly accepted definition of a full hybrid (there's no "real" definition of course) is a car that can travel using only the electric motor. I argue IMA cannot do this; it's been many months since the last time my car did since I gave up putting the effort into trying to activate it. Whereas a Prius just does it automatically. You'd never see posts asking how to activate EV mode in a Prius; it just happens.

That's debatable anyway. But yes, by "full hybrid" I mean HSD, Ford's system, and the Dual-Mode system GM/Chrysler/BMW is developing.

 

Just my input, I was disapointed when I found out that the HCHII can not accelarate in EV mode from a stop. However, I use it everyday for about a two to three mile continuous distance on my way to work at about 40 MPH or so. Very easy to do with little practice. Takes a lot of time looking at the dispaly to stay in the mode until you get the hang of it without looking.

 

ack. i hate these kinds of debates. you're right, there is no "real" and i would argue even "common" definition of "full hybrid". in fact, many sites and articles quote the hch.ii as a "full" hybrid while the hch.i is not b/c the hch.ii can operate on electric only. so that's why i've tried to stay away from content-free definitions like "full" and "mild" hybrids. they make no sense from an engineering standpoint and only serve to confuse the public. they're great marketing terms.

to demonstrate, it can be argued that "full" hybrids can be powered by either the gas engine or electric motor at any time but does not require both. in this definition, the hch.ii would be a "full" hybrid and the prius would not be because it requires that the electric motor run all the time at high speeds even if the battery pack is depleted (very inefficient).

so i'll try to sum up what it is that i think you're trying to say about the prius vs. the honda civic without using marketing jargon like "full" and "mild" and without unnecessarily bashing the ima system for something as basic as a bigger magnet: the prius has a more powerful electric motor and more batteries that allows it to accelerate from a standing stop up to 35mph or so.

btw, the primary reason for that big electric motor is not to start the car from a standing stop. that's incidental. that big 67hp motor has to be there to compensate for the inherent flaw in hsd that requires the torque output from the ice to be balanced at high road speeds by the electric motor (mg2). this flaw is very inefficient and wasteful and significantly hampers the prius as higher road speeds. touting the accidental byproduct of this flaw as a "benefit" is sheer marketing genius. don't fall for it.

 

I don't pretend to have an engineer's knowledge of it; I only know I get much better mileage on the highway in a Prius than in a Civic Hybrid. Also there's the simple observation that when Toyota takes a V-6 and slaps HSD on top of it, the result is more fuel-efficient even on the highway, from what I've read. Whereas obviously that same V-6 with IMA would be no different on the highway since IMA would not be used. (Note: the Accord Hybrid does not use the same V-6 as the regular Accord.)

My *guess* is it works because the engine can run at its most efficient speed, even if it's generating less power than is needed immediately, or even if it's generating more power. Excess power can recharge the batteries and inadequate power can use the batteries to make up for it. Whether or not it actually does this, I don't know, but it demonstrates the usefulness of running the engine just to generate electricity.

GM + Chrysler + BMW are jointly developing a system like Toyota's but more complicated; it's designed to eliminate exactly the inefficiency you describe. It will no doubt be significantly better than IMA and possibly better than HSD, if put in the same car with the same engine of course. (Initially it'll just be in full-sized SUVs for some reason.)

 

The reason that the engine is always spinning is more fundamental than that. The ICE and the electric motor are attached. They turn together. They always turn at the same RPM. One cannot turn without the other. Stopping the ICE must also mean stopping the electric motor.

 

Yeah and the reason they're connected is basically because of what I stated.

 

Who came first, the chicken or the egg?

 

The egg obviously. The egg is simply the first stage of life for the chicken, so by definition it must come first. It's like asking what comes first, a baby or an adult?

This message brought to you by CGameProgrammer, Knower Of Everything.

 

lol! this is too funny. you cite the gm/daimler/bmw jv as a system that "will no doubt be significantly better than IMA..." are you kidding me?? the dual-mode hybrid system that they're making is a hack. give me a break. gm, daimler and bmw have been caught with their pants down. they underestimated hybrid demand in the u.s. and now need to play catch up. the current hsd system is a joke because of the glaring flaw in its design that requires the electric motor to runs itself to death at higher crusing speeds. so, they purchase patent rights from toyota for hsd and then slap on a second planetary gear set, two clutches and lots more complexity just to make a hybrid that according to their own press release:

"will reduce fuel consumption at highway speeds much more effectively than available single-mode systems and achieve at least a 25% improvement in composite fuel economy in full-size truck applications." — Tom Stephens, Group Vice President, GM Powertrain

so let me get this right: let's take a seriously flawed system, fix it by slapping a second planetary gear set, a set of clutches, more complicated algorithms and control units and be happy with a 25% improvement in combined fuel economy?? oh and by the way, we will only sell it in full-sized suvs because the system is so complicated and costly that we need to bury the costs in the price tag of a huge suv. my guess is that this jv will fail and the dual mode system will be abandoned in favor of either electric motors in the wheels or a variant of a plug-in parallel system (read: ima system).

mercedes entered into the jv as an insurance policy and b/c it was great pr. they will wait for gm to introduce their first dual mode suv; watch it fail then continue on with their current diesel/hybrid plans. they currently use a variant of a plug-in parallel hybrid system very similar to ima in their sprinter commercial vehicle. there is speculation that mercedes will extend this hybrid technology and introduce a phev/diesel for the u.s. market.

sorry to be so blunt but nothing can touch ima in terms of elegance, economy, efficiency and end results.

fact: ima is a beautiful, simple, elegant hybrid system.
fact: ima is less costly to build and maintain.
fact: ima is more easily adapted to existing powertrains.
fact: ima delivers excellent mpg results on par with other hybrid systems.
fact: ima does not suffer from significant energy waste at higher cruiser speeds.
fact: ima doesn't need to lug around additional weight from a big heavy motor, a second motor and a big battery pack to drive those big, heavy motors.