During the Work Truck Show 2020, I had the opportunity to ride along in the Class 6 Cummins Electric Truck with Range Extending Engine (ETREE). Only one of two in existence, this project vehicle features a 26,000-lb gross vehicle weight and a 123 KW-hour Lithium-Ion battery. The Cummins ETREE is sponsored by the Department of Energy Vehicle Technologies Office.
The Cummins ETREE is a series hybrid vehicle. A 4.5L Cummins engine is attached to a generator that charges batteries. There is an electric traction motor that drives the wheels. The goal of the ETREE program was to achieve a 55 percent reduction in fuel consumption for a defined pickup and delivery route, which spurred the development of this particular series hybrid system.
Depending on the vehicle’s speed and load, it can travel between 60 - 80 miles in pure electric mode, without ever utilizing the range extending diesel engine.
The Cummins ETREE is optimized for a last mile delivery duty cycle. The specific vehicle I got to ride along in is being sent to Frito Lay in April of this year. Frito Lay has a dedicated route that they will implement this vehicle into that will utilize and maximize the operational feasibility, capability, and benefits of the ETREE system.
An interesting aspect of the ETREE system is that the driver can enter route data into the HMI (human-machine interface) display, mounted inside the cab. The route length is entered and the DEEM software system will analyze the anticipated route, utilize the battery capacity to depletion, then initiate the range extending diesel engine if needed. The DEEM software also calculates this dynamic to ensure that the range extending engine is only started once. Furthermore, the system will also utilize all of the battery’s charge first before utilizing the diesel engine.
There is also a switch mounted on the dash of the vehicle that can initiate a transition from electric power mode to range extender diesel power mode, or vice versa. This transition can be initiated any time the vehicle is on, whether the vehicle is driving or parked.
Riding along in the vehicle was an interesting experience. When in full electric mode, operation was quiet and smooth; when the diesel engine was running, operational performance stayed the same aside from the increase in noise. I am intrigued with the concept behind the ETREE system and am interested to see how Frito Lay will utilize and capitalize off of its capabilities. In the end, I think that the industry could see an adoption of such series hybrid options as the range extended system can stave the range anxiety that some have with full battery electric vehicles while still providing the benefits and flexibility offered with electric operation.
