"My guess is that you can make a serial (hybrid) heavy duty pickup that weighs the same as a conventional diesel powered pickup. Its configuration will depend on how far you want to go with plug-in power versus how long you want to sustain power climbing a 15% grade towing 20,000-pounds, as to how you size the generator and the batteries. If you use a bigger generator, you can trade-off with a smaller battery pack," says Mr. Wright.
To limit the need for a bigger generator, the truck’s chassis would be redesigned to squeeze more batteries around the bed. The live axle and leaf springs would be chucked in favor of an independent rear suspension, reclaiming wasted space beneath the cargo box.
Heavy duty pickup owners care as much about range as they do towing capacity, so they don’t have to make frequent fuel stops hauling a trailer. Mr. Wright believes his system would provide at least a 300-mile range, with the same weight and towing capacity as current trucks.
"If you’re going to build (plug-in serial hybrid) heavy duty trucks to compete with the current ones, you can’t compromise on (towing, weight, and range)," says Mr. Wright.
Where compromise would occur is in the purchase price. A serial hybrid pickup won’t be cheap, costing an estimated $20,000 or more than a conventional diesel powered truck.
"Cost is going to depend on the price of fuel. If fuel is $4.00/gallon and you’re driving 25,000 miles per year, and you’re getting 10-mpg towing, that’s $50,000 over five years. If you did the same thing with a plug-in hybrid, using only grid power, it would be about $6,000. That means you could afford to pay quite a bit more for the vehicle," says Mr. Wright. He also expects a hybrid’s lower maintenance costs to also provide further economic incentive.
But to Mr. Wright, the thing that makes pickup trucks such a good target is that most of the time they operate well under their maximum rated power.
"That’s not an efficient way to build a car," he says. "You need to have the peak power to tow and accelerate, but most of the time you don’t use it. Cylinder deactivation is one way of getting at the problem but it doesn't nearly solve it."
The electric motors and batteries would operate optimally across a wide range of power needs, from the equivalent of as little as 20-horsepower during 40-mph unloaded, steady state driving, to as much as 1000-hp for brief periods climbing a steep grade with a 20,000-lbs trailer.
It all comes back to fuel economy though, and Mr. Wright thinks poster-child green-tech vehicles like the Toyota Prius are a dead-end compared to pickups.
"Consider just one 10-mpg truck and one 50-mpg Prius," he says. "Drive them both 100-miles. The truck uses 10-gallons, the Prius 2-gallons. Improve the Prius to 100-mpg, drive another 100 miles. Now it only uses 1-gallon, you saved 1-gallon. But improve the truck by 12%. Now it does 11.2-mpg, and in 100-miles it will use 8.9-gallons, an improvement of 1.1-gallons. If you doubled the trucks mpg, from 10 to 20, you'll save 5-gallons, 5 times as much as doubling the mpg of the Prius."
Mr. Wright is predicting his approach will deliver fuel economy that's close to double today’s figures while towing, and the equivalent of 80-mpg during unloaded, stop-and-go, commute-style driving.
"When you compound this effect with the higher sales volume of high fuel consumption vehicles like pickups," he says, "you can see why it's completely pointless to improve the Prius, and crucial to improve the trucks."