Expanding applications for Deere natural gas on-highway engines: new ratings, new electronics, lead expansion into transit bus, utility truck and refuse uses; LNG coming - On-Highway Technology

Diesel Progress North American Edition, Oct, 2002 by Mike Osenga

A recent order from MetroLink, the Moline, Ill., transit system, for 12 of a possible 18 CNG-fueled El Dorado buses, all powered by John Deere 8.1 L engines, marks the latest step in John Deere Power Systems' expanding gaseous-fueled engine program.

Ten of the 30 ft. Metrolink buses, which began transit operation in July, started life earlier this year at the Salt Lake City Olympics, "which certainly proved the reliability and operation of the vehicle under demanding conditions and at altitude," said Deere's Tom Cummings, manager, natural gas engine sales.

Since its launch in 1996, Deere's natural gas engine program has expanded from its base in school buses to include commercial transit buses, refuse vehicles, Class 7 utility trucks, as well as pick-up and delivery trucks.

Deere's natural gas engine program has centered around its 8.1 L model 6081HFN engine. A turbocharged, air-to-air charge-air cooled engine, the 6081HFN has been available with a 250 hp at 2200 rpm rating developing 800 lb.ft. of torque at 1350 rpm.

Now, Deere's Waterloo, Iowa-based Power Systems group has introduced a 275 hp at 2200 rpm rating for the 8.1 with the same torque output, as well as a 280 hp rating at 2200 rpm that develops 900 lb.ft. of torque at 1600 rpm.

The new ratings are among a number of technical changes Deere has made to 6081HFN, as its natural gas program begins to come of age. For example, an LNG capable model is due for introduction early next year, and current engines now feature new humidity and knock sensors. "The humidity sensor package is one of the key elements within the natural gas market that is critical for good performance of these engines," Cummings said.

The engines are all gasified on the production line at Waterloo. Cummings said that while the lower portion of the engine is still a diesel base, the upper half and anything to do with the combustion system is specifically designed and sourced for natural gas operation. "All are natural gas derived components that we developed in conjunction with Southwest Research Institute," Cummings said.

Glen Chrusciel, business manager, natural gas added that the natural gas engines have a lower compression ratio (10:1), a cylinder head unique to this use, special pistons and valve seat inserts, a new ECU and a Woodward injector block. Cummings added that all three versions of the engine will be released with oxidation catalysts early in 2003. The power cylinder has recently been upgraded and the engine is now using a unitized coil module.

Cummings and Chrusciel said that the biggest technical change for the natural gas engine line is the launch of the new John Deere Electronics-built ECU.

The new "full featured" ECU incorporates: a road speed governor; cruise control, auto resume; elevated high idle control, primarily for vehicles with air conditioning; in-cab idle adjustment; remote PTO; dual throttle, ABS with traction control; engine brake interlock with a decel light; foot pedal inhibit/throttle interlock; a range of engine protection inputs for both derate and hard shutdown; pulse width modulation fan control; A/C input; coolant temperature input; throttle charge temperature; transmission sump temp; shutdown override switch; shutdown reset; and shutdown alarm. The ECU is J1939 CAN and J1587 capable, Deere said.

The John Deere gaseous engine program began in 1996 with the application of Deere's first lean burn, closed loop, adaptive learn natural gas engines in a Blue Bird All American school bus chassis. In 1999, Thomas Built also began offering the 250 hp 8.1 L natural gas engine in its Saf-T-Liner bus chassis. Both are targeted primarily at school bus use in California.

The next step was smaller transit buses. Deere had gained some natural gas engine experience in commercial uses in Blue Bird transit buses, though the majority of Blue Bird applications are in school buses. The first significant program in small low-floor transit buses is the Moline MetroLink application mentioned above in ElDorado National's EZ-Rider, a heavy-duty 30 ft. low-floor transit bus, a 102 in. wide vehicle with seating for up to 29 passengers plus standees.

Next was a recent order from Sonoma (California) Transit for the same bus and engine configuration. Cummings said five buses are due to enter service in Sonoma this year. Blue Bird also introduced a new commercial bus, the model XCEL 102HF, at last month's American Public Transit Association Expo with the 250 hp 8.1 L engine as the standard CNG engine option.

Deere has also made moves recently in the heavy-duty transit bus market. "This is a market that requires you have 50,000 miles and/or two years of operating experience before you can get your foot in the door," Cummings said.

To do that, Cummings said Deere identified "a couple of sophisticated, technologically advanced transit agencies that were currently using natural gas." The results were 280 hp model demonstration programs with Queens Surface Transit, Queens, N.Y., a two-year program with over 50,000 miles of operation in Orion V buses.