Caterpillar, the prolific maker of construction equipment has announced that for 2010 they will be selling the D7E, a diesel-electric bulldozer.
The diesel engine can be shut down when the bulldozer is not in motion, as opposed to idling, similar to the start/stop technology showing up in automobiles. In addition, the engine can be tuned for greater efficiency when operated in steady-state mode, again similar to the range-extender concept of the Volt.
The D7E represents a mid-range dozer between Caterpillar’s popular D6 and D8 models, and commands a price premium of 20%, or $100,000, over a standard D7R. But that 20% can be recouped in as little as two years thanks to fuel savings of 10-30%. Plus, the electric-diesel drive system offers better power than its predecessor, which sold just 300 units in the U.S. last year (compared to 2,000 D6 and 700 D8 machines).
But nobody buys a bulldozer based on gas mileage. Rather, the efficiency is based on how much material can be moved per gallon of fuel, where the D7E really shines. Caterpillar dropped their trademarked “high sprocket” design, and turned the transmission into essentially twin power cables. It should be noted that this hybrid drive does not store electric power, but rather the 9.3 liter diesel engine powers a strong electric engine. This means even more instant torque, and since its a Caterpillar it can stand up to tough situations.
This is a really good idea from Catepillar, which is beginning to pay attention to the opportunities for improving efficiency in service vehicles, shipping, and heavy equipment. These are the sorts of applications that can tolerate the higher up-front costs, whereas hybrid and electric vehicle price premiums are currently a limiting them to a niche market. Hopefully we will begin to see a lot of these sorts of developments with marine engines as well.