With gas prices in the mid 90's in parts of Canada, the timing is right to launch GM's hybrid full-size pickup, combining V8 power with reduced fuel consumption and portable 110-v, 20-amp power.
By Howard J Elmer
First announced in 2001, the GMC Sierra parallel hybrid pickup truck has arrived in Canada. And right on cue - wildly fluctuating gas prices are a fitting backdrop for the sale of a conventional looking pickup that promises 15% fuel savings while also doubling as a portable generator. First offered to the commercial market, 50 of the trucks have already been sold and more orders are pouring in.
But what exactly does GM mean by "hybrid?" Frankly, it's a word that's often not defined and its usage varies from company to company.
Tom Stephens, vice-president, GM Vehicle Integration, explains GM's take on itThis is a hybrid with a twist," he said. "Unlike our competitors, who are looking to use the electric motor as a power assist on a small powertrain and giving up some utility to accomplish that, we give you all the acceleration, towing and hauling capability you've come to expect by using a truck V-8 engine. The energy captured through regenerative braking and being able to shut off the engine at idle improves fuel economy by up to 15%."
Instead of a conventional starter motor and alternator, GMC uses an electric motor that is integrated into the drivetrain between the engine and the transmission. This provides starting power and generates electricity. It also reduces weight and parts. Each time the truck coasts, it is making up to 4.8 kilowatts of electricity that is stored in a 42V battery pack, which (among other uses) can power tools off a pair of 110V, 20-amp outlets in the cab and bed.
Where the truck really saves fuel, though, is at stoplights, stop signs, or when idling at the landing. Here, the gasoline engine actually stops running, but most of the accessories continue working using the stored electrical power. To keep the systems alive, the hybrid truck's power steering is run by an electrically driven hydraulic pump rather than the traditional belt-drive system. Similarly, the heating system has an electric pump that keeps hot water circulating even when the engine is off. When the light turns green, or the chatting at the landing ends, the driver steps on the accelerator, and the gas engine kicks in again. (Think about how a gasoline golf cart works; same principle.)
The truck gets more out of each litre of gas because of the engine start/stop function and regenerative braking (which is what turns the motor into a generator each time the truck decelerates). The 4.8 kilowatts of electricity generated by the system is stored in advanced lead-acid batteries to keep the size and cost of the 250 lb battery pack reasonable. But as more 42V systems and by-wire controls become available, this architecture should also become smaller and lighter than the 12V counterpart, which will further improve fuel efficiency.
The hybrid truck has obvious environmental advantages, and could give forestry and logging companies a "good news" PR edge. As an added bonus, think how handy it would be to have a portable generator sitting around the work site, or even in your driveway - particularly after last summer's hydro letdown here in Ontario. Next time, I'll plug my house into my truck.
Though the MSRP for the public version of the hybrid truck has not been announced, GM sources suggest that the cost will be between $3 000 and $3 500 more than a similarly equipped non-hybrid pickup. GM has also begun delivering a diesel hybrid (military version) pickup truck equipped with a fuel cell auxiliary power unit (APU) to the US Army. This diesel hybrid is said to improve fuel consumption by 20% over conventional diesels, reduce emissions and provide troops with reliable electrical power. With fuel transportation costs reaching up to $400 a gallon depending on location or battlefield operations, that fuel consumption reduction could well save millions of dollars.
The four-door pickup is powered by a 6.6L Duramax diesel engine, and mated to a parallel hybrid electric system. This hybrid system is under development by GM for future commercial applications. This system uses a split power continuously variable transmission (CVT) with integral electric motors and an energy storage system. Power demands are satisfied with a combination of electric and diesel power, as needed. The storage system is a lightweight, nickel-metal hybride-based system that weighs a third less and is half the size of lead-acid batteries. In addition, this diesel-electric hybrid powertrain can operate as a self-contained generator, capable of providing up to 30kw of DC and AC electricity for operations in the field.
