The test will involve a Class 6 vehicle that’s slated to be available to FedEx Ground within the next year. In September Parker Hannifin had joined with the US Environmental Protection Agency (EPA) to develop a hydraulic series hybrid system for Class 6 port yard hostlers. These diesel units move freight from vessels to trucks at ports. The hostlers differ from on road Class 6 trucks since their top speed is 25 mph.
As the company explains, the Parker drive eliminates conventional transmissions along with their weight and maintenance needs. The drivetrain uses accumulators to store energy. They support a higher energy flow without overheating and are more efficient at charging and delivery power than when batteries are used as storage devices.
EPA will continue to provide technical assistance to Parker, including engineering services, test equipment and facilities. EPA’s initial simulation modeling of city driving to come with FedEx Ground’s use of the new vehicle confirms potential savings greater than 50% in fuel mileage efficiency. As with other hybrids, energy saved when brakes are applied is reused for vehicle acceleration.