I'm not going to explain all of this, but the purpose of the GM transmission is so that it can deal with heavy loads. If this is the system I'm thinking of, it has a set of planetary gears that allow the electric motor(s) to add torque.

Here's a link. I think there was even more detailed info on someone elses site:
http://www.leftlanenews.com/2006/04/...hybrid-system/

If GM were to try for EV only, there are really only two ways of doing it AFAIK... ridiculous gearing, or a huge motor and electrical system capable of delivering very high current all the way through.

I still think the EV only mode advantage is very slight, but at this point it warrants its own discussion elsewhere.

 

It is a shades of gray rather than an issue. The IMA makes a lot of sense because it marries low-end torque and regenerative braking with the engine. On either side are the 'autostop' only, light weight 'hybrids' and the 'EV' capable hybrids:

1) BAS hybrids - saving idling fuel; smallest E-hp/G-hp and wheel-hp = G-hp

2) IMA hybrids - expanded engine operational modes and electric power assist; medium E-hp/G-hp and wheel-hp = E-hp+G-hp

3) EV hybrids - limited EV mode, typically 30 mph or less; higher E-hp/G-hp and either wheel-hp = E-hp or wheel-hp = E-hp+G-hp

Changes in the control laws for a "BAS hybrid" would make it function almost like an IMA using a belt instead of a direct mechanical link. Then if you took a second BAS motor and battery pack and connected it to a retractable 5th wheel, you'd have an "EV hybrid." Sounds like fun.

Bob Wilson

 

I would've preferred that Honda had designed the HCH2's EV-only mode to be 0-5mph, say. I don't need to cruise in EV mode, but I'd love to be able to creep forward in stop-and-go traffic without the ICE powering up. Isn't 13hp enough to move a small car that much?

 

The HCHII has a 20hp electric motor. I agree it would be nice to have the EV mode in creeping traffic. At least for me, I would not have many occasions to use it, so I would not be willing to pay much extra for it.

 

It is plenty of power. The problem being fighting the ICE compression losses. However, I understand one of the modification around for the Insight allows manual operation of the electric motor. I just don't know if anyone has tried that for the HCH.

Heck, at 13-20 hp, there should be enough 'creep' power even if you have to turn the ICE. With some sort of compression relief, it would work. Then there is the 5th wheel approach.

It might be more practical to rig up a 5th wheel that comes down when slow-speed EV mode is needed. This is not a trivial problem but it may be easier than hacking into the HCH control systems. But the HCH is not a system I have a lot of information about.

NOTE: the rear wheels of the HCH are unpowered and I suspect there is a suspension beam between the two. One easy hack would be to put an electronic only, rear-wheel axle/differential in place. There would need to be some shifting around but it would solve the problem without having to hack the existing IMA design.

Bob Wilson

 

This pretty much sums up what I really like about the upcoming Tahoe / Yukon hybrids. There are a couple million people a year who feel the need to buy full size utilities & pickups. I'm not talking Equinox, VUE, Escape sized utilities or Tacoma, Colorado, Ranger size trucks. I'm talking the big ones. Tahoes, Yukons, Explorers, Sierras, Silverados, F150. If those folks truly need the size and functionality they will continue to buy them. If they can get a hybrid that can improve their fuel economy 25%, Excellent! Do it!

It's actually one transmission that operates in two modes (Dual-Mode / 2- Mode). It is developed from a fairly typical electronic / hydraulic driven planetary gear transmission, but the electronic controls allow for continuosly variable gear ratios to allow the engine to function at it's most efficient range through most driving experiences. This is similar to how a CVT works, but instead of using a belt or chain driven CVT, the planetary gearset ratios are managed through sophisticated software management. The belts and chains used in CVTs would be unsuitable for attaining the types of towing and payload requirements these trucks need to be capable of.

Peace,

Martin

 

http://www.greencarcongress.com/2006...mlerchrys.html

 

All the energy from a non-plugin hybrid comes from the tank of gas - the electric component just recovers wasted kinetic energy. EV mode would be critical - if not essential to a plugin hybrid.

 

There is a market, right here in Lakedude land. My truck is getting up there in age and I will eventually need a new boat hauler. The Escape Hybrid would be perfect except that it cannot pull a full size boat. None of the current hybrids (or any truck for that matter) meet my needs (the other hybrid SUVs are out of my price range). There is no reason a truck or SUV couldn't get mid twenties to high thirties and still get the boat to the lake.

I'm looking forward to the dual mode tranny and also the upcoming mid sized diesels.

 

Delta, I agree that without EV only mode, plugin doesn't make as much sense... especially for city driving.

In terms of global warming, I think plugins can vary anywhere between a win or a slight loss. Allow me to explain:

I found two companies that are producing are about ready to produce an add-on to make the Prius pluggable. One says that with a 9KW charge, you can go 30 miles. Another says they have a 9kwh battery, but you can only use 6.4kwh for EV only mode, then you get battery, but again, 30 miles.

So I'll assume 6.4kwh = 30 miles. If you travel 46.7 miles at this rate of consumption, you will emit the same amount of CO2 as burning a gallon of gas, if your power grid is exclusively coal.

On one hand, 46.7mpg in terms of Co2 emissions still isn't bad, and I doubt most people are exclusively using electricity derived from non-co2 recapturing coal plants. On the other hand though, this assumes you kept the Prius in EV mode, which is unsuitable for highway traffic, and presumably for much of metro area traffic. Once you beef up the system to deliver more juice to a bigger electric motor, you become less efficient (fighting aerodynamics). Oh, and you're production cost (which is energy usage, which is CO2 emissions) goes up too.

So if you have a nuclear power grid, a plugin would be a slam dunk. If your power grid is primarily coal and you're driving a plugable or EV that travels at 60MPH+ in EV mode, it's not really progress in terms of global warming.

In either case, it appears to be a step in the right direction for decreasing our reliance on foreign oil. But still, it is only part of the puzzle. The power grid has to be cleaned up and eventually made renewable if plugins or EVs are going to be a legit permanent solution.