Two in One
22 OVERDRIVE NOVEMBER 2009 C ou rt es y of In te rn at io na l T ru ck s I n the near future, hybrid Class 8 trucks combining powerful motor-generators in the drivetrain and a new type of potent bat-tery will make over-the-road trucks signifi cantly more fuel-effi cient than today's models. The improved effi ciency will emerge largely from the ability to store energy recovered during braking. Fuel savings will come from generating power for in-cab hotel loads while the truck is running, or with the engine in an effi cient, loaded, fast-idle operating mode, and storing it. This energy will provide the power needed to cool the cab and run onboard devices like refrigerators, televisions and microwaves via the batteries. The process will reduce the need for idling and its harsh effect on engine oil. More savings will accrue from lower maintenance costs because hybrid systems help in easing the workload of high-maintenance clutches and foundation brakes. Hybridization is likely to be a big fuel saver in all applications except cross-country routes, where minimal braking is needed. Hybrids so far retain the standard service brake system. The traditional air brakes are necessary both because the hybrid braking effect works only through the drive wheels and because, at least at Electric and diesel muscle combine in hybrid systems that store energy, cut fuel usage and reduce operating costs. If you want to see the face of tomorrow's powertrain, look at what's on the road today. BY JOHN BAXTER Navistar showed off this Walmart International tractor, incor-porating Arvin-Meritor's hybrid system, during a Hybrid on the Hill event last June in Washington, D.C. Two in one