Top 100: Mercedes Simplifies EGR; Automates a Six-Speed

Sept. 28, 2010

Mercedes-Benz used reed valves instead of multiple flap-type valves and a wastegate turbocharger rather than variable geometry turbo in the exhaust-gas recirculation (EGR) system for its six-cylinder MBE4000 and four- and six-cylinder MBE900s. The MBEs cost less than most competitor engines when installed in Freightliner, Sterling and Western Star. The 12.8-liter MBE4000 (with ratings up to 450 horsepower at 1,550 pounds-feet of torque) weighs 2,117 pounds, as much as 330 pounds less than competitive diesels.

Mercedes also brought the Automated Gear Shift (AGS) transmission to North America for Freightliner and Sterling mid-range trucks. The electro-hydraulic shifting mechanism makes an automatic out of a six-speed synchromesh gearbox. SmartShift allows the operator to override the computer and manually upshift or downshift by pulling or pushing a stalk mounted to the steering column.