Tech Preview: GM Two-Mode Hybrid Pickups

[Dano702]

Originally Posted by maxaccel

ok Im no expert on this hybrid technology but wouldnt it get even better mpg if they used a tiny 4 cyl, or even smaller ICE ,acting strictly as a generator charging the batteries and in turn run those electric motors continously at all speeds?

The thing i like best about this dual mode set up is the V8 power . My company has a few half tons and a few 2500 size trucks . I will replace those as soon as i can buy Dual Mode trucks . But only if they do the same job as the old trucks do .

A small 4 banger cant pull a 6,000 lb trailer up mountians at 80 can it ? I dont need a prius , i need something to make a living with .

[chakis24]

Originally Posted by maxaccel

ok Im no expert on this hybrid technology but wouldnt it get even better mpg if they used a tiny 4 cyl, or even smaller ICE ,acting strictly as a generator charging the batteries and in turn run those electric motors continously at all speeds?

yeah, if it were a car. you gotta remember, this is still a full size half ton pickup thats expected to do the work of a regular ICE pickup. if they could figure out a way of doing that, then sure. but a truck is work/capabliity first.

[maxaccel]

Originally Posted by Dano702

The thing i like best about this dual mode set up is the V8 power . My company has a few half tons and a few 2500 size trucks . I will replace those as soon as i can buy Dual Mode trucks . But only if they do the same job as the old trucks do .

A small 4 banger cant pull a 6,000 lb trailer up mountians at 80 can it ? I dont need a prius , i need something to make a living with .

it wouldn't be the 4 banger puling, it would just charge the batteries ,
and those turn the electric motors,which obviously have enough torque to pull the truck for some distance on electric power alone,

so as long the small generator=ICE engine
(it could even be small one cylinder maybe) makes enough juice/electricity at all times,it should theoreticaly be able to run at high speed also using only those electric motors.

and (some) electric motors have way more torque then even a big block!
see the White zombie electric dragster on youtube,
its just unreal as it has so much power all the way even at high speed,

http://www.youtube.com/watch?v=-PRkpn2xmjc

[MelvinJ]

Originally Posted by maxaccel

it wouldn't be the 4 banger puling, it would just charge the batteries ,
and those turn the electric motors,which obviously have enough torque to pull the truck for some distance on electric power alone,

so as long the small generator=ICE engine
(it could even be small one cylinder maybe) makes enough juice/electricity at all times,it should theoreticaly be able to run at high speed also using only those electric motors.

and (some) electric motors have way more torque then even a big block!
see the White zombie electric dragster on youtube,
its just unreal as it has so much power all the way even at high speed,

http://www.youtube.com/watch?v=-PRkpn2xmjc

You can't get more power out of a system than you put into it. You can store some power while you aren't using it, and let it out in a burst later, but it's not sustainable. When the batteries run low, the ICE is providing ALL the power, whether it's routed through a generator, then a battery pack, then electric motors, or directly through a transmission to the wheels (which under steady state conditions, is more efficient). If the ICE is putting out 75 hp, the truck will move like it's powered by a 75 hp engine eventually. In a car like the Volt, this is fine because it's not expected to haul much weight, and 75 hp teamed with a moderately sized battery pack can make the car perform like a regular ICE car with probably twice the power (at least).

But picture a 5800 lb. Tahoe pulling a 6000 lb. load. The batteries from a moderately sized pack will be gone in a couple of minutes pulling this kind of load. If you could put in ginormous batteries that would store a huge amount of energy and let the little ICE/generator run ALL night to charge the batteries, you might get away with it. But then you'd be hauling around 4000-5000 lbs of batteries which in turn comsumes a lot of energy just to move. The type of system you are proposing doesn't scale well. Neither does the simple hybrid system in the Prius. The Two-Mode does.

What you are proposing borders on a perpetual motion machine.

[Jnielo]

Where are the electric motors in the two-mode system? Are they in the transmission?

[DuSpinnst]

Originally Posted by Jnielo

Where are the electric motors in the two-mode system? Are they in the transmission?

Yes.

[john1701a]

Originally Posted by MelvinJ

The type of system you are proposing doesn't scale well. Neither does the simple hybrid system in the Prius. The Two-Mode does.

Try not to be so vague. Lack of detail is very, very misleading...


Two-Mode scales from FWD midsize 6-cylinder sedan to a 4WD full-size SUV able to tow 6,200 pounds.

HSD scales from a 4-cylinder compact car to a 4WD midsize SUV able to tow 3,500 pounds to a full-size sedan capable of 438 horsepower.

Now look at the worldwide market. Consider what types of vehicles there are more sold of. One hybrid system can serve a much larger number of consumers than the other.

There's more to the business than just engineering.

JOHN

[maxaccel]

Originally Posted by MelvinJ

You can't get more power out of a system than you put into it. You can store some power while you aren't using it, and let it out in a burst later, but it's not sustainable. When the batteries run low, the ICE is providing ALL the power, whether it's routed through a generator, then a battery pack, then electric motors, or directly through a transmission to the wheels (which under steady state conditions, is more efficient). If the ICE is putting out 75 hp, the truck will move like it's powered by a 75 hp engine eventually. In a car like the Volt, this is fine because it's not expected to haul much weight, and 75 hp teamed with a moderately sized battery pack can make the car perform like a regular ICE car with probably twice the power (at least).

But picture a 5800 lb. Tahoe pulling a 6000 lb. load. The batteries from a moderately sized pack will be gone in a couple of minutes pulling this kind of load. If you could put in ginormous batteries that would store a huge amount of energy and let the little ICE/generator run ALL night to charge the batteries, you might get away with it. But then you'd be hauling around 4000-5000 lbs of batteries which in turn comsumes a lot of energy just to move. The type of system you are proposing doesn't scale well. Neither does the simple hybrid system in the Prius. The Two-Mode does.

What you are proposing borders on a perpetual motion machine.

not at all,
heres a prototype of military hybrid electric Hummer that uses just such a configuration, small 4 cylinder generator turning electric motors in each wheel.
and this was back in 98,so today with better batteries it should be even more efficient,sure the generator would run continuously but it would still get better mpg than big motors we use now to pull heavy loads.
notice thats 9100lbs vehicle here
http://rds.yahoo.com/_ylt=A0oGkkmQG1...14/humvee.html
Hybrid Humvee Brings Stealth To The Battlefield
By Bill Moore
Editor in chief EV World:This Week

OMAHA, Nebraska -- 5 January, 1998. Representatives of the news media assembled on the grounds of Universal Studios in Orlando, Florida for a demonstration of a new hybrid-electric HMMWV (Humvee). In a steady drizzle, a standard diesel-powered "Hummer" rumbled into view and slowly approached the damp, but curious group of reporters. It quickly became apparent that something was amiss, this wasn't the vehicle the press had come to see. Instead, with their attention momentarily diverted, the real hybrid-electric Hummer silently crept up from behind to within inches of the crowd before the announcer asked the assembly to turn around to view what some are calling the Army's new "Corvette in Camouflage."

You couldn't have asked for a more effective demonstration of the stealth capabilities of this one-of-a-kind prototype military vehicle. The result of a joint engineering effort by a consortium including the US Army's Tank-Automotive and Armaments Command (TAC), DARPA, the Southern Coalition for Advanced Transportation, Unique Mobility, PEI Electronics and others, the hybrid-electric HMMWV cost less than $2 million dollars in development costs, according to Daniel Tudor, senior program manager for PEI Electronics of Huntsville, Alabama.

Corvette in FatiguesWhile the Hybrid-Hummer looks like the standard Humvee on the exterior, complete with olive-drab and flat black camouflage, underneath its workaday fatigues is a remarkable power plant capable to surprising acceleration and speeds up to 80 miles per hour, a good 10 miles faster than the standard issue HMMWV. Its zero-to-fifty mph time is seven seconds, twice as fast as the stock model. It can climb a 60% grade at 17 mph, two and half times faster than stock. In addition, the vehicle gets twice the fuel economy at 18 mpg enabling it to carry a smaller fuel tank, while retaining the same 300 miles range. The vehicle can also ford streams up to a depth of five feet without swamping or stalling.

The only trade-off of the current prototype design is a 540 pound loss of payload, presumably taken by the heavy lead/acid batteries. The hybrid version has a rated payload of 1700 pounds, while the stock version is 2,240 pounds. The GVW for both vehicles is identical at 9,100 pounds.

Small HumveeThe heart of this new generation military vehicle is its hybrid-electric propulsion system consisting of four 55kW brushless DC electric motors (peaked rated to 75kW), one for each wheel and a 1.9 liter turbo-charged diesel engine-generator set capable of turning out 55kW of electric power. The diesel-generator can provide power either to the drive train or to the vehicle's 288 VDC advanced lead/acid battery pack. Rated at 350 hp in hybrid mode, the combination gives the Hybrid-Hummer its sports car like performance, as well as its stealth capabilities which is activated by throwing a switch on the console between the two front seats. Going stealth turns off the turbo-diesel and draws power from the 85 amp hour battery pack giving the Humvee a 20 mile range in silent mode (40 miles using NiMH batteries). /quote

[MelvinJ]

Originally Posted by john1701a

Try not to be so vague. Lack of detail is very, very misleading...


Two-Mode scales from FWD midsize 6-cylinder sedan to a 4WD full-size SUV able to tow 6,200 pounds.

HSD scales from a 4-cylinder compact car to a 4WD midsize SUV able to tow 3,500 pounds to a full-size sedan capable of 438 horsepower.

Now look at the worldwide market. Consider what types of vehicles there are more sold of. One hybrid system can serve a much larger number of consumers than the other.

There's more to the business than just engineering.

JOHN

What's misleading is when you post what appears to be(and should be) a response to what I actually wrote, then ignore what I wrote. I said that the system in the Prius wouldn't scale up. Are you telling me that the system in the Prius is EXACTLY the same as the one in the Highlander and Lexus hybrids? Aren't there additional planetary gearsets in Toyota's larger hybrids (which puts it closer to GM's Two-Mode)? Doesn't the LS600h hybrid include additional clutches like the GM Two-Mode? Then it's NOT the same system as the one in the Prius. I said nothing about the entire HSD lineup.

The LS600h's fuel economy ratings really aren't that impressive compared to the Two-Mode Tahoe. Yes, it's got more power, but it's close to 600 lbs lighter, has FAR less aerodynamic drag, and 1 liter less engine displacement. Yet it's 20 mpg city rating is one mpg behind the Two-Mode Tahoe rating, and it's 22 highway rating merely ties the Tahoe. Lord knows what this version of HSD would do in a Tundra or Sequoia. Even this version (clearly more sophisticated than the Prius HSD that I REFERRED TO) isn't that impressive in larger vehicles.

I will readily admit that the Two-Mode is too expensive to scale down to smaller vehicles. I don't think we will even see Two-Mode mid-size sedans (that's where the E-Flex will come in). But there are millions of medium to large vehicles sold every year, and they use the most fuel. Should they be ignored? Improving the efficiency of the biggest fuel users makes more sense than going after the smallest.

And please, John, if you respond to this post, actually respond to what I've said here. Don't act like I said something else, just so you can launch into one of your pro-HSD rants.

[MelvinJ]

Originally Posted by maxaccel

not at all,
heres a prototype of military hybrid electric Hummer that uses just such a configuration, small 4 cylinder generator turning electric motors in each wheel.
and this was back in 98,so today with better batteries it should be even more efficient,sure the generator would run continuously but it would still get better mpg than big motors we use now to pull heavy loads.
notice thats 9100lbs vehicle here
http://rds.yahoo.com/_ylt=A0oGkkmQG1...14/humvee.html
/quote

Unfortunately, this article says nothing about HOW LONG the hybrid Hummer can sustain these performance figures. Yes, it can cruise at 80 mph with it's 350 hp electric rating, but with only 74 hp coming from the diesel (which is ultimately all that's powering the motors), it won't be long. The batteries will run out and you will be left with 74 hp. This is fine for the military because they don't travel at 80 mph. They move very slowly. I've passed their convoys on the freeway.

To get a system that would would be capable of moving 12,000 lbs. (roughly the Tahoe's GCW), with the aerodynamic drag of a high trailer, at highway speeds, up mountains, you need WAY more than 74 sustained hp. GM could have added a heavier battery pack, deleted the V8 and dropped in a micro-engine and gotten great fuel economy numbers and a vehicle so compromised for the way they are typically used that there would be no point to it anymore. What they did instead was take produce a vehicle with almost no compromised abilities (a 1000 lbs or so off the tow rating) and 45% better city mileage. Much smarter.