German Hybrids Planted in North America

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The growing ranks of hybrid trucking enthusiasts (they’re out there) have been waiting for this one for some time; namely the entry of ZF Friedrichshafen into the North American hybrid truck market. 

Nearly a household name in Europe, with a long history of supplying driveline componentry, steering systems and other chassis components to car, bus and truck manufacturers there and elsewhere, it’s nowhere near as well known on this side of the fat pond.

One of its divisions, ZF Sachs, supplies the tiny clutches used by Formula One racecars, indicating that the company is always at or near the cutting edge. It’s based in Friedrichshafen, Germany but has interests and facilities worldwide.

You’ll most likely know it in the context of the ZFMeritor FreedomLine transmission

And now we have the announcement that ZF and California’s ISE Corporation (ISE), which designs and manufactures series hybrid propulsion systems and components for heavy-duty vehicles, plan to collaborate on the development and supply of a complete line of parallel-electric hybrid drive systems and components for North American vehicle markets. 

The combined expertise of the two companies will result in a broad product portfolio of series and parallel hybrid -­ electric drive systems and components.

Collaboration details of their recently signed MOU (memorandum of understanding) include ZF’s intention to utilize ISE expertise for integration engineering, sales, subsystem assembly, and service support for ZF hybrid systems and components for North American commercial vehicles. 

The transmission experts at ZF are teaming with ISE

ZF has already developed several parallel-hybrid configurations for various applications in the transit-bus and truck industries. I’ve driven a couple of them in European trucks, and they performed like, well, like hybrid-electric drivetrains do. Tons of torque off the line and all that. The real test of such things, of course, is in the realm of efficiency proven over time, so a seat-of-the-pants impression isn’t worth much.

As well, ISE also plans to develop and market an ISE-branded parallel hybrid drive system that incorporates ZF hybrid systems and components in North America.

ISE is an interesting little outfit, dwarfed by ZF — 136 employees vs. 61,000, for example — but it’s successfully working in the area of heavy-duty electric series hybrid drive systems, with offerings including gasoline hybrid, fuel-cell hybrid, diesel hybrid, and battery-dominant drive systems. The 2010 Olympic Winter Games will be a showcase for ISE technology, as we’ll see several ISE-developed vehicles in use there.

This joint effort will make the North American hybrid scene even more interesting than it already is. And the extra competition seems likely to accelerate the commercialization process which has been slowed by the recession, of course, but not destroyed. Interest remains high on both the user and the builder fronts, and it seems to me that few other corners of the commercial vehicle world have as bright a future as this one. 

And here’s something you’d have to label counterintuitive. New York City is presently a hotbed of hybrid activity.

Specifically, the New York Department of Sanitation (DSNY), which is testing refuse trucks of several sorts. Among them a Mack TerraPro low-entry truck with Mack/Volvo hybrid-electric technology and two Crane Carrier units with Heil bodies

Mack says its TerraPro is the first production-intent parallel diesel-electric hybrid truck in the U.S. designed specifically for class 8 heavy-duty applications and meeting the EPA 2010 emission standard.

It has a rear-loading refuse packer body moved along partly by a 325-hp Mack MP7 diesel with SCR exhaust aftertreatment technology. 

Manhattan Project 2009: The New York sanitation
department is at the forefront of hybrid use.

The diesel-electric hybrid part of the powertrain features an integrated starter, alternator, and electric motor.

Bosch Rexroth’s HRB tester is in use now, a Crane Carrier LET2 truck. In fact, two identical HRB-equipped trucks will be part of the evaluation.

The system uses a hydraulic pump/ motor connected to the driveline to capture kinetic energy during vehicle braking. When braking, the pump/motor acts as a pump, absorbs energy from the driveline and delivers a retarding force to the drive wheels, pumping hydraulic fluid into a nitrogen-pressurized accumulator.

During acceleration, the pressurized gas pushes fluid out of the accumulator, and the pump/motor then acts as a hydraulic motor, assisting the engine and reducing the fuel required to launch the vehicle.

Not only is there fuel to be saved when using such regenerative braking, but the brakes themselves end up with longer lives — there’s less brake dust strewn about too.

The New York sanitation folks replace brakes about once a year, which takes the truck out of service for at least two days. The hope is to extend brake life by some "50 percent or more."

The ISE modular hybrid drive system is in three evaluation trucks for DSNY, tests with the first vehicle have just started. The Crane hybrid rear loader is the first of its kind in the refuse and heavy truck market, with a rated GVWR of 72,000 lb. The electric drive system is self-contained in three separate modules.

The hybrid drive cabinet with ultracapacitor energy storage and overall system controls, together with the engine-driven generator assembly, are mounted behind the cab. The electric traction motor is mounted between the frame rails of the truck chassis and takes the place of the truck’s conventional transmission.

The refuse trucks are also equipped with ISE’s onboard Remote Diagnostics System (RDS), which includes GPS and allows for real-time performance monitoring through a web-based interface.

ISE says series hybrid electric systems offer the potential to operate accessories such as air conditioning and hydraulics in all-electric mode, without the need to run the diesel engine, providing a pathway to battery-dominant vehicles operating in zero-emission, all-electric mode. ISE also says such an electric vehicle is capable of providing emergency backup power and could eventually have a plug-in feature enabling ‘vehicle to grid’ capability.

ISE’s hybrid propulsion system is powering more than 200 vehicles with more than 9 million miles of accumulated driving. 

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Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to

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