From the ground up
While options may be limited with manufacturers offering only their own proprietary engines, transmissions and axles, vertical integration has also eliminated a lot of trial and error and problems on the road.

By Paul Abelson, senior technical editor

It wasn’t that long ago that your options on spec’ing drivetrain components seemed infinite. Except for Mack producing its own engines, transmissions and axles, you could choose between Caterpillar, Cummins and Detroit Diesel engines in whatever power ratings you wished. Behind your engine, you could put a transmission from Dana, Eaton Fuller or Rockwell (now Meritor). Power would then flow to a Dana, Eaton or Rockwell drive axle.

None of the truck builders (except Mack) made engines, transmissions or axles. Two seemingly identical Peterbilts could be sitting side by side. One might have a Cat 425 engine, Dana 18-speed, two Rockwell drives and an Eaton steer axle. The other could have Cummins 444 power, an Eaton 13-speed gearbox, Dana drives and a Rockwell steer axle. The choice was the buyer’s, provided there were no incompatible specifications.

In those days, one major LTL company operated thousands of plain-looking day cabs from several manufacturers. Roadway’s vice president of maintenance tracked maintenance costs closely, knowing what parts had high failure rates or high reliability by manufacturer and part number. He ordered trucks accordingly, with more than 30 pages of specifications. He specified everything, including clamps, hoses, fans, wheel hubs and even fasteners.

The approach in the U.S. was “How can you expect someone who never used or maintained a truck to know what works and what doesn’t?”

Europeans took a different approach. Each OEM offered only its engines, transmissions and axles. Components were selected by the truck manufacturer, not the purchaser. The manufacturers argued, “How can you allow someone who is not an engineer to design something as complex and safety related as a truck?” Buyers told their sales representatives how they operate. The reps told engineering staffs and they specified the power, torque, number gears and ratios that met the buyers’ needs.

Each system worked well in each geographic area, until a number of events began to change things. Mercedes Benz, now Daimler, bought Freightliner. Volvo bought White Trucks, establishing its presence in North America. Renault bought Mack, and later was bought by Volvo. General Motors sold Detroit Diesel to Roger Penske, and its share of White-GMC to Volvo. Freightliner bought Western Star and Ford heavy trucks, renamed Sterling.

In 2000, other forces moved us closer to vertical integration. Daimler bought Detroit Diesel, while all the engine companies scrambled to meet the new EPA emission standards by October 2002.

Other truck builders stopped selling Detroit engines. “Why should we put a competitor’s engine in our trucks,” they asked, “especially with all the engineering required to meet the EPA regulations?” Soon, Freightliner was the only manufacturer installing Detroit engines.

New engines would be needed to meet the increasingly stringent EPA requirements, especially those due in 2007, 2010 and beyond. Cummins realized the need for a totally new engine platform. Although their N Series was virtually bullet-proof, they introduced the ISX and re-engineered their other models. The new laws led Detroit to drop their venerable Series 60.

Detroit pioneered electronic controls, but by 2000 all engine makers had them. There is an axiom in electronics that computers’ capacity to process data doubles every two years. That means that from 2002 when the most recent regulations went into effect, computers’ capability grew by about 12 times.

Early electronic engines had relatively few inputs to process. They sensed throttle position, rate of change of pedal position, air intake flow, temperatures at the engine and exhaust and a few more. Signals to squirt fuel went to the injectors.

Today, more than 30 sensors feed data to the engine’s processor and components so the computer can tell injectors when and how to squirt fuel, with multiple pulses, during combustion. The engine’s central processing unit doesn’t just give commands to injectors. It now controls components like fan hubs. It communicates with other components’ processors. That lets automated transmissions work.

Humans think in three-dimensional terms: length, width and height. Engineers call them x, y and z. Some people visualize a fourth dimension, time. Combustion engineers and others think in multi-dimensional terms, adding multiple sensor inputs to create a “fuel map,” a proprietary set of data that tells an engine what to do under varying combinations of input.

Fuel maps are quite costly to develop. They contain operational and competitive information, not to be shared. But to make the latest automation work, information sharing between electronics is essential. Volvo’s iShift works only with Volvo engines, as does Mack’s mDRIVE and their engines. Detroit’s new DT12 transmission communicates only with Detroit engines. Cummins has gotten in the game by partnering with Eaton for the latest generation of UltraShift Plus transmissions.

These proprietary relationships are extremely costly, and there is probably not enough engineering manpower to allow the kind of universal interchangeability we once knew. The trend toward proprietary parts is increasing, with Detroit now supplying axles in addition to engines and transmissions.

The trend continues with hub, brake, air conditioner, steering and other component makers partnering with truck builders. Will this help or hurt the truck buyer? I am reminded of a truck maker’s engineer who told of the old days when customers chose their components. Warranty costs and related downtime were excessive. The truck builder limited choices and supplied only complete systems. Warranty problems virtually disappeared overnight as only one supplier had total system responsibility. And users were much happier.

In the old days, trucks were good for half a million miles, with engines needing overhauls at half that. Today, million-mile trucks are commonplace. Perhaps the lack of choice has hurt only our egos because it has given us longer-lasting trucks. LL