Both Mercedes-Benz diesel engines sold in Freightliner heavy- and medium-duty trucks will be fitted with cooled EGR to meet federal '04 emissions rules. The company also announced that it will introduce an automated version of its 6-sp. manual transmission for its medium-duty Business Class M2 early next year.
The heavy-duty 12.8 L MBE4000 and medium-duty MBE900 were not required to meet the Oct. '02 emissions deadline set as part of a court case brought by EPA against a number of diesel engine makers, and Freightliner was able to continue selling those engines without advanced emissions-reduction systems. Now, however, they must comply with the originally scheduled Jan. '04 deadline for achieving the lower emissions levels.
In conjunction with cooled EGR, the two '04-compliant MB diesels will use fixed-vane turbochargers with waste gates instead of the variable vane turbocharger design used by some other engine makers. The major benefit is lower cost.
New electronic controls for both will also add full diagnostics and the ability to use Detroit Diesel's Diagnostic Link software.
The changes will add approximately $3,000 to the cost of the HD diesel and $2,000 to the medium-duty model. Fuel economy will drop by no more than 2%, according to Freightliner officials. The MBE4000 will retain current power and torque ratings, ranging from 350 to 450 hp. and peak torques of 1,350 to 1,550 lb.-ft.
The MBE900 continues to come in 4- and 6-cyl. versions, but will have two additional displacement options, 7.2L in 6-cyl. and 4.8L in 4-cyl. Power ratings will range from 170 to 330 hp., with peak torques of 420 to 1,000 lb.-ft.
The Mercedes-Benz Automated Gear Shift (AGS) transmission used electronic controls and hydraulics to manage all gear changes. The “two-pedal” design is based on the company's 6-sp. manual and will be available with the MBE900 in the Business Class M2 early next year in two torque ratings — 520 lb.-ft. and 660 lb.-ft.
Combined with Freightliner's SmartShift lever, drivers can choose to let the transmission make all shifts or choose to control shifts manually. Benefits are said to include better fuel economy and less clutch wear compared to manual models.