There is increasingly strong demand for hybrid vehicles as customers recognize the bottom-line benefits of reduced fuel use and service requirements, as well as the civic impact of responsible environmental practices.

—Dan Sobic, Peterbilt General Manager and PACCAR Vice President

The hybrid Model 335 is powered by the new 6.7-liter PACCAR PX-6 diesel engine and a parallel hybrid system developed with Eaton Corporation. Peterbilt expects the hybrid model will result in a 30- to 40-percent reduction in fuel use through the combined improvement of on-road fuel economy and stationary jobsite operation.

The hybrid Model 335 on display at the HTUF meeting November 14 through 16 will be equipped with a Terex body and 55-foot aerial. Peterbilt and Terex have jointly developed the fully integrated chassis and body combination. The body was specially designed to allow for installation of the hybrid components on the chassis during manufacturing, allowing the vehicle to drive off the assembly using hybrid power. The design also allows for easy access to hybrid components for improved serviceability.

The truck and body communicate through a new J1939 digital controller. This interface senses hydraulic demand from the body and automatically engages the hybrid system. Under a full charge, the PTO (Power Take Off) can operate for approximately 25 minutes at which time the vehicle will automatically start the diesel engine and recharge the hybrid’s batteries. A full recharge takes 3 minutes. During eight hours of operation, the diesel engine will run for less than one hour, according to Peterbilt.

Hydraulic Hybrid. Also on display at the meeting will be a Peterbilt Model 320 featuring Hydraulic Launch Assist hybrid technology. (Earlier post.) The Class 8 vehicle is specifically designed for refuse applications and uses its kinetic energy to conserve fuel and assist in acceleration.

The Hydraulic Launch Assist technology was also developed in partnership with Eaton. The system is particularly beneficial in heavy stop-and-go applications, such as refuse collection. In addition to the enhanced fuel economy, brake wear can be reduced by more than 50 percent, improving serviceability requirements and reducing operating expenses.

Hydraulic Launch Assist works by recovering a portion of the energy normally lost as heat by the vehicle’s brakes in the form of pressurized hydraulic fluid. This fluid is stored in an on-board accumulator until the driver next accelerates the vehicle.

Stored energy launches the vehicle during the initial, high-fuel consumption start from stop, followed seamlessly by power from the primary engine. In performance mode, the stored energy is released and blended with engine power at launch. This can significantly improve acceleration due to the high power density of hydraulics.