2005 GMC Sierra Review

Specifications

New Hybrid Alternative Makes Sense

With the current, previously unforeseen fuel prices ruining the financial forecasts of countless contracting businesses, it only makes sense to get more fuel efficient pickup trucks and SUVs to market as soon as possible.

Toyota could have had an edge in this segment if it had introduced its full-hybrid system fitted to a Tundra, but some analysts would say they dropped the ball. GM hasnt, however, and therefore will bring its new Chevy Silverado and GMC Sierra gasoline-electric hybrids to a dealership near you later this year.

No other automaker has announced what seems like an absolute no-brainer, stuffing a hybrid-electric system into a vehicle class that is infamous for guzzling fuel. GM introduced its “FlexPower” hybrid powertrain to the media at the 10th National Clean Cities Conference and Expo in Fort Lauderdale, Florida. Since the introduction GM delivered fifty new Chevrolet Silverado (the GMC Sierras clone) extended cab hybrid pickups to Miami-Dade County for fleet use. Without a doubt this will just be the first of such orders, with governments and environmentally conscious corporations quick to realize that going green looks good in the public eye.

But GMs hybrid isnt just a way for politicians and corporate execs to get on the good side of environmentalists. Its also a much more efficient hauler than its gasoline-only powered equivalent. Starting with a 5.3-liter V8 and 4-speed automatic transmission, the addition of an electric motor and battery power storage allows it to achieve 10 to 12 percent improvements in fuel economy over the standard Sierra 1500 pickup.

John Gaydash, GM Fleet and Commercial marketing director stated, “These hybrid pickups will save more fuel than gasoline-powered pickup trucks, with no compromise in performance or utility. In addition, Miami-Dade will now have the flexibility and productivity of generating wall-quality electrical power from the GM pickup truck when in remote locations.”

In a nutshell, GM replaces the conventional electric starter and alternator with a compact electric motor, itself integrated between the engine and transmission in a patented, space-efficient manner. Unfortunately there isnt any added torque provided by the electric motor to help out when towing heavy loads, but nevertheless the electric motor does supply power to the transmission that in-turn delivers torque smoothing to the drivetrain. Up to 14,000 watts of continuous electric power is generated.

If youre familiar with a V8s usual gurgling exhaust note, or the chugging of an even louder diesel, youll probably get a bit of a shock when the hybrids engine stops running while the truck is stationary. Releasing the brake pedal will immediately spark the V8 engine to life, restoring full power.

Where the GM system differs from Toyotas full-hybrid technology, also adapted by Ford and soon Nissan, is that it uses what some experts consider a less sophisticated partial- or mild-hybrid system - similar to that used by Honda in its Insight, Civic Hybrid and soon to be released Accord Hybrid. The jury is out as to which is better over the long haul, but partial systems are not considered quite as efficient as full-hybrid systems, being that the gasoline engine needs to be running while under way - unless coasting. Full-hybrid systems can drive on electric power alone, until the batteries need to be recharged at which time the gasoline engine restarts.

The Sierra Hybrid does take advantage of regenerative braking, however, which uses the kinetic energy developed by braking to recharge the batteries.

Another Sierra advantage is that when the truck is stopped and the gasoline engine is shut off, the HVAC system can still be used - not the case for any of Hondas hybrids. Turn on the A/C while at a stoplight in the Insight, for instance, and the engine immediately springs to life. The Sierra, on the other hand, incorporates an electric pump for circulating hot water to heat the cabin, plus cold, dry air for the air conditioning system. An electrically driven hydraulic pump allows the driver to turn the powered steering wheel while stationary, without the need for the gasoline engine to power up.

Its difficult to guess if contractors or campers will appreciate the four 120-volt 20 amp (2,400 watt) electrical auxiliary power outlets more, but its a fair bet each will make good use of those under the rear bench seat and in the pickup bed. Ideal for everything from plugging in a laptop to powering a table saw, the power source can be activated while the truck is running or after being shut off and the keys taken out of the ignition. The systems power supply circuits are protected by a ground fault detection system so overloads and short circuits wont be a problem. According to GM, the new Sierra hybrid could maintain power for up to 32 hours non-stop before needing to fill the tank. In an intelligent move, the engineers designed it to shut down before needing a complete refill, to allow enough gas to get to a filling station.

GMCs Sierra Hybrid will be available to retail customers as a 2005 model this fall. No doubt the automaker will look to expand its full-size HEV advantage to other models shortly, with the Yukon and Yukon XL on the agenda - although no official announcement has been made.

GM is really onto something here, offering hybrid technology in a vehicle genre that really needs to optimize efficiencies. The practicality of a rolling power generator will be hard to pass up by contractors, which is just the edge GM needs to overcome Fords segment dominating F-150. The new Sierra Hybrid is a strong sign that hybrid technology is here to stay; at least it is until a significantly widespread hydrogen infrastructure makes it obsolete. That will be a long time away, however, despite what hydrogen proponents say. Until then, hybrid electric powertrains will be the dominant alternative to conventional internal combustion engines. Welcome to the green world GM.