TORONTO, (Nov. 22, 2004) — Fuel costs are through the ozone layer, ’07 engines loom on the horizon, and any gizmo that offers better diesel economy gets its hearing.

Among the serious contenders is SuperDrive — a new technology out of Michigan alleged to deliver a 20 per-cent improvement in fuel economy. “Everybody’s looking for savings,” SuperDrive’s COO Don Ochs told Today’s Trucking.

While Ochs says no Canadian fleets have purchased SuperDrive yet, he’s confident that will change soon. SuperDrive is already being used by at least one Ohio-based fleet and a Kentucky urban transit system. Among the truckers is Kirk NationaLease of Sidney, Ohio, which is set to order 100 Volvo tractors with SuperDrive.

“We don’t buy fuel,” says Tom Vondenhuevel, Kirk’s vice-president of purchasing, “but our leasing customers do. Some of them have been operating the new engines and have seen their fuel economy go down.”

SuperDrive is not an add-on. The brainchild of inventor Herman Mitchell, who is now the vice-president for R&D at SuperDrive, the innovation is based on a low-speed engine that runs through a hydrostatic, continuously variable transmission, or CVT. It requires major alterations to a truck’s drivetrain and modifications to the engine.

Retrofitting is expensive and time-consuming, at least for each newly handled vehicle, which requires designing, fitting and fabrication of new brackets and other parts. Retrofitting could cost from $14,000 US to $35,000 US, but most of the cost would be incurred in the original engineering.

Still, Ochs suggests that once installed, depending on the size of a fleet, the system could pay for itself within a few years.

Retrofitting involves — we hope you’re sitting down — removing a vehicle’s clutch and clutch linkage, transmission and driveshaft, then installing SuperDrive components.

These include a hydraulic pump and driveline motor connected by hoses and fittings, which comprise the hydrostatic CVT. There’s also a smaller pump that supplies compressed air for injection into the exhaust stream, and a compact electronic control module. The ECM works with engine controls to regulate fuel and RPMs, and controls operation of the pumps and motor.

Removal of the conventional drivetrain saves about 1,000 pounds in a class 8 vehicle. But the system’s main claimed benefits are its fuel savings and reduced emissions, plus its easy operation.

The main pump, mounted directly behind the engine and driven by it, is an axial type with five cylinders arrayed around a swash plate. The plate moves to alter the cylinders’ displacement, and therefore the flow of hydraulic fluid. This in turn constantly changes the drive ratio. Pressurized fluid runs through hoses to and from the motor that’s mounted ahead of the rear axle’s differential; a truck with a live tandem has two motors, one ahead of each differential.

Operating pressure changes depending on the use, the terrain, and the vehicle speed. The ECM notes the situation and orders more power from the engine and adjustments of the swash plate inside the axial pump. The ECM’s programming includes 48 ratio-type “steps” for the swash plate, but they are so closely spaced that changes are not noticeable to a driver.

A SuperDrive-outfitted class 8 runs about 800 to 1,300 rpm. This takes advantage of a diesel’s torque peak, which is usually 1,000 to 1,200 rpm. And it yields “fewer combustion events per mile,” while allowing for more complete combustion, which is largely responsible for the fuel economy gains, the company says.

— with files from Heavy Duty Trucking