September 3, 2003

2004 Toyota Prius. Photo: Grant Yoxon, CanadianDriver.com. Click image to enlarge

The scoop on hybrid vehicles
by Jim Kerr

High fuel prices, the Kyoto Accord, smog alerts. These all impact the vehicles we drive. Hydrogen and electric cars will be on our roads in the future but for now they are still not up to providing everyday transportation. In the short term, hybrid vehicles will fill some of the needs and there will be several models on the road.

Currently, only three hybrid vehicles are seen on our roads; the Toyota Prius, the Honda Insight and the Honda Civic. Ford is scheduled to offer a hybrid Escape SUV soon and GM is going after the commercial truck market with full-size hybrid pickups later this year.

See Also: First Drive: 2004 Toyota Prius Across Canada in a Honda Civic Hybrid Test Drive: 2003 Honda Civic Hybrid Test Drive: 2001 Honda Insight GM Technology Tour

While all use electric motors, generators and battery packs, there are many differences between these vehicles.

The Toyota Prius has to be the largest volume production hybrid vehicle on the market. For 2004, Prius has received its second design, offering improved efficiency and more compact packaging of components. It also works a little different than the other hybrids.

While most hybrids use the gasoline engine as the main source of propulsion and add electric assist when needed, the Prius uses the electric motor as its main propulsion. Step on the accelerator (I can't call it a gas pedal anymore) and the Prius silently pulls away from a stop. When more power is needed or at higher speeds, the gasoline motor starts and assists the electric motor. Slow down and the electric motor becomes a generator, helping to both slow the car down and recharge the battery pack.

2003 Honda Insight. Photo: Honda 2003 Honda Civic Hybrid. Photo: Paul Williams, CanadianDriver.com Ford Hybrid Escape concept. Photo: Ford Chevrolet Silverado PHT. Photo: GM Click image to enlarge

The Honda Insight is without doubt the most recognisable hybrid in the world. This two seater aluminum bodied coupe was built to showcase Honda's hybrid technology. Although the car has not sold in large numbers, the streamlined styling of the Insight has caught the attention of many drivers. So has its fuel economy. It's rated at 88 mpg or 3.2 litres/100 km on the highway.

For 2003 Honda has taken the technology tested on the Insight and refined the package to fit into a Civic. There is still room for five passengers, the battery pack and controllers are much smaller and now fit behind the rear seat, and the electric motor/generator has been made thinner. Both the Insight and Civic Hybrid use IMA (Integrated Motor Assist) technology - a thin electric motor the full diameter of the flywheel fits between the engine and transmission.

This electric motor is used to start the gasoline engine, provide extra power when the gasoline engine isn't enough and help slow the vehicle through regenerative braking. An impressive dash display shows the driver fuel level, battery charge level and whether the electric motor is assisting or charging.

Ford's Hybrid Escape uses two electric motors/generators built right into the transaxle. The gasoline engine is still the main propulsion source, and the battery pack is located beneath the cargo area floor. NmH batteries are used for long life and there are actually rows of "D" cell batteries positioned in stacks and mounted in a case to make up the battery pack. Why "D" cells? They are a common battery size and there is ample production capability already around.

The latest hybrid is GM's 2004 Parallel Hybrid Truck or FlexPower truck as it is sometimes called. This pickup uses a Vortec 5300 5.3 litre V8 and 4L60E automatic transmission combined with a 14 kilowatt integrated flywheel starter/generator. These trucks deliver the same high output - 285 horsepower and 325 lb.-ft. torque as other Vortec 5300s and perform as well as their regular gasoline-engine counterparts. Like the Honda Insight and Civic, the electric motor is located between the engine and transmission, so physically it is a relatively easy system for the engineers to add to a regular powertrain.

A 42-volt hybrid battery system is included, complete with twin 110 volt, 20 amp AC power outlets in the cab and pickup bed. The 2004 Chevrolet Silverado and GMC Sierra 1500s go into production for fleet and commercial customers first but I expect to see them on dealer's sales lots as production ramps up.

Why a hybrid pickup? Estimated fuel economy savings of 10 to 15% combined with a significant reduction in emissions are an even greater benefit on large vehicles compared to small cars, and commercial vehicles are usually operated more so the savings could be significant.

Hybrids aren't the answer for everyone, but they will play a role in our future transportation.

Jim Kerr is a master automotive mechanic and teaches automotive technology. He has been writing automotive articles for fifteen years for newspapers and magazines in Canada and the United States, and is a member of the Automotive Journalist's Association of Canada (AJAC).

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