A brief test drive in a couple of Freightliner Business Class trucks showed the MBE900 to be a very willing and civilized option to the Cummins and Caterpillar power available in Freightliner’s medium-duty chassis.
Last March, Freightliner announced plans to buy up to 20,000 MBE900-series engines a year from the heavy-duty powertrain unit of its corporate parent, DaimlerChrysler AG.
The engine will be standard in all FL50, FL60, and FL70 Business Class trucks.
DaimlerChrysler-built transmissions and axles will follow, Freightliner says, creating a fully integrated powertrain.
Freightliner has six targets for its Mercedes-powered trucks: beverage delivery, food services, refuse collection, municipal utilities, tow trucks, and emergency vehicles. These are all vocational applications where a small, high-torque/low-rpm engine that’s durable, electronically controlled, and easy to mate with an automatic gearbox is desired.
The trucks available for the test drive included a somewhat abused FL 60 crew-cab truck, loaded to a 26,000-pound GVW and powered by an MBE900-280, which drove through an Allison MD3060. The other was a sweet FL 70, with the 230-horsepower MBE900 coupled to the G85 six-speed MB transmission and loaded to a GCW of 40,000 pounds, a substantial load for this relatively low-powered tractor.
Fortunately, we tested the low-powered truck first. This was a near-production unit with excellent sound insulation and cab sealing to complement the MBE900’s quiet, yet competent performance.
The lack of noise is in part due to the fully electronic-controlled, unit-pump injection system. The electronics can squirt fuel into the combustion chamber with great precision, reducing both noise and exhaust emissions so the engines are fully 1999-compliant with no exhaust aftertreatment.
The electronics also allow for tailoring of the torque curve, which peaks with a completely flat curve from 1200 rpm to 1800 rpm, before tapering off as the engine runs out to its 2300 rpm rated speed, with a further 200 rpm of governor droop. The 660 pound-feet of this engine over such a broad rpm range made it a much better performer than the eliminated horsepower would indicate. Indeed, with the 210-hp unit, Freightliner says the torque is nearly 30% higher than Navistar’s International DT-466, and 35% higher than a T-444E.
Over a varied route around Portland, Ore., we found the Business Class tractor competent, with more pickup than the diminutive 6.4-litre displacement would suggest.
The six-speed Mercedes-Benz transmission was a delight, with an ease of shifting especially in the lower ratios that was as light as a passenger car’s.
Any driver who can handle a standard shift should feel right at home with this powertrain spec. The 280-hp engine coupled to the Allison in the 26,000-pound straight truck shows what a rocket the little Business Class can be with some extra horsepower.
Shift points still had not been optimized, but the step-off of this combination was impressive and the ability to keep up with urban traffic meant it was a delight.
Freightliner is not keen to compare its MB option with existing North American drivetrains, but it is impossible not to prefer the much lower noise levels from the Mercedes-Benz engines. The transmissions will not be available for a year.
That is a great shame, as the low shifting effort and fabulous match of ratios with the torque characteristics of the MBE900 engines make the little Business Class a really easy truck to live with on a daily basis.
ROAD NOTES: MBE900
* Freightliner offers two displacements and several ratings for the MBE900: a 6.4-litre, in-line, 6-cylinder MBE900 engine, and a 4.3-litre, in-line 4-cylinder version (available later in the year). The 6-cylinder is rated from 190 to 300 horsepower with peak torque of 860 lb. ft. @ 1250 rpm. The 4-cylinder offers ratings from 150 to 190 hp with up to 520 lb. ft. of torque.
* The MBE900 will eventually have a couple of transmission options, as Freightliner tries to source automatics from someplace other than Allison Transmission, where product has been in short supply. Freightliner wants to mate the MBE900 with a DaimlerChrysler automatic, and it’s been stocking up on five-speed Aisin A581s, an automatic transmission made by Aisin Seiki Co. Ltd. of Japan, a Toyota subsidiary. The A581 weighs 360 pounds.
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