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Enova Hybrid Truck Prototype Reduces Fuel Consumption by 31%

Post-transmission parallel hybrid drive. Click to enlarge.

Enova Systems has integrated and delivered a post-transmission 120 kW parallel-hybrid truck to a major unnamed North American truck manufacturer as an initial milestone in a joint-development program announced earlier this year. (Earlier post.)

As delivered, the hybrid drive system provided an average reduction in fuel consumption of more than 31%, and an increase in mileage in excess of 48%. Given the demonstrated performance, Enova believes that the vehicle could be in production in the second half of 2006.

The confirmed fuel consumption and mileage improvements provide the necessary benefits to make a very good business case.

—Mike Staran, Enova Vice President of Marketing

Enova is taking a dual-path approach in offering both series- and parallel-hybrid drive systems. The company has developed a variety of heavy-duty hybrid drives, including a series-hybrid system with a diesel genset; two variations of a pre-transmission parallel hybrid drive system; and the post-transmission parallel-hybrid system used in the project above.

Mack Truck is using a post-transmission parallel hybrid in a refueler hybrid prototype (earlier post).

The 120-kW hybrid drive is designed for light trucks, delivery vans, and mid-sized buses using electric and series hybrid-electric propulsion. This system can provide 1,664 Nm of drive shaft torque when used with the Enova gear-reduction unit and operates on a DC input voltage that can range from 250–425VDC.


Bob H

If this is true it is the magnitude (31 %)of the mileage increase that will end the current price problem for a barrel of oil. The oil companies should not have been so greedy. It leads to the development of the alternative technologies.


Hum ... how is it that the decrease in fuel consumption % doesn't match the increase in milage?

Isn't fuel consumption measured by gas milage? :)

tom deplume

The math is pretty close. If a vehicle improves its mileage from 10 mpg to 15 mpg it has increased mileage by 50%. Fuel consumption per 100 miles goes from 10 gal to 6.6 gal a reduction of 33%.

Dave Zeller

Many times when we read about hybrid truck technology, one thing is noticed by its conspicuous absence:

"What is the conventional vehicle's fuel economy, and what it the fuel economy of the newer hybridized version?"

Out of curiousity, and after much research, I usually discover that the fuel economy of both vehicles is rather poor. For example, most modern 45 passenger city buses get about 1.6 m.p.g., whereas the hybridized versions are lucky to achieve 2 m.p.g. Thus, hybrid technology will typically achieve an improvement of 25% in fuel consumption.

Compare this to the typical 45 passenger, four stroke diesel equipped bus of the late 1950's, which could easily manage 15 m.p.g.

It makes one wonder where the engineers have gone wrong over the last 50 years!

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