Turbine development for the trucking industry has made major progress since Freightliner built its first turbine truck in 1965 using simple split shaft turbines manufactured by Boeing and later by Caterpillar. Improvements in the turbine engine include regenerators to recover waste heat from the exhaust system and a means to improve part throttle efficiencies with the features of power transfer and variable geometry. These features also have the facility of providing retarding which will help the overall vehicle performance along with making the engine more adaptable to conventional type transmissions.
During these years, Freightliner has run its turbine truck on the highways hauling revenue freight and testing different power train configurations and learning about the application of the turbine engine to a truck chassis. During this test period the engine was run at 300 and 360 horsepower. Two drive train configurations were tested, a specially adapted Allison MT42 transmission and a high-speed transmission drive train operating at 10,000 rpm developed by Dana for this test truck. It was determined that the chassis weight for the turbine engine installed can be reduced well in excess of 2,000 pounds when all drive components are optimized. These tests have shown that significant gains can be made in maintenance costs and tire wear with the use of the turbine engine, besides providing reliability. Fuel figures for the simple turbine show that the need for the regenerator to improve the overall fuel efficiency and, further, the need for variable geometry or power transfer to improve the part throttle operation.
The turbine engine will probably find its first home in the long haul operations where weight savings and reliability will come into play. To gain its place in the reliability figures, the accessory items with the turbine must also perform well with all the other control switches on the turbine. The electrical system still proved to be the most troublesome on the vehicle.
With the investments being made in turbine development and its good stance in the ecology field, we can be certain that the turbine will be here, and our objective is to be ready for it when it does arrive with the proper drive train, chassis configuration and operating application.