Diesel no image

Published on September 18th, 2009 | by Christopher DeMorro

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Caterpillar Builds World’s First Hybrid Bulldozer

September 18th, 2009 by  
 

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This one may offend you more sensitive types as “ironic” or not green at all. But the fact is, the world needs bulldozers. Lots of them. But until now, anyone seeking a hybrid bulldozer was out of luck. But Caterpillar, the prolific maker of construction equipment has announced that for 2010 they will be selling the D7E, a diesel-electric bulldozer.

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.

It is also interesting to note that Caterpillar has been developing this technology since the late 1990s, and didn’t intend to market it as a “green” technology per se. But green is in, and this setup can save up to 24 liters of fuel (about 6 gallons) over an 8 hour period. That may not seem like a lot, but consider that many of these machines run six days a week, year round in warmer states. It is an important step that many of us may not have even considered at first. But if the D7E can become a sales success, surely more like-minded companies will follow suit.

Source: Engineering News Record

Photos: Caterpillar


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About the Author

A writer and gearhead who loves all things automotive, from hybrids to HEMIs, can be found wrenching or writing- or else, he's running, because he's one of those crazy people who gets enjoyment from running insane distances.



  • Tim Cleland

    It’s funny they chose an electric hybrid. I would think a bulldozer would be a good candidate for hydraulic hybrid…all that stopping and starting of that huge mass and no need to cruise.

  • Tim Cleland

    It’s funny they chose an electric hybrid. I would think a bulldozer would be a good candidate for hydraulic hybrid…all that stopping and starting of that huge mass and no need to cruise.

  • ChuckL

    Tim, It is NOT a hybrid. It is a diesel-electric.

    From the Cat web site: “It uses a Cat C9 engine powered by ACERT® Technology – compliant with Tier 3 regulations for criteria pollutants – and an on-board generator to efficiently convert engine power into AC electrical current that drives the tractor.”

  • ChuckL

    Tim, It is NOT a hybrid. It is a diesel-electric.

    From the Cat web site: “It uses a Cat C9 engine powered by ACERT® Technology – compliant with Tier 3 regulations for criteria pollutants – and an on-board generator to efficiently convert engine power into AC electrical current that drives the tractor.”

  • Eric Carter

    This doesn’t look like a hybrid at all, just a diesel-eletric drive similar to what many vehicles with the high-torque requirements would use. If it was a hybrid then shouldn’t “batteries” be called out on that image? Hybrid implies two sources of power, which this does not. It’s closer to a train that a Prius or Volt.

    Assuming that picture, the power flow appears to be as follows:

    1) diesel fuel power engine

    2) engine turns generator

    3) generator powers electric motors/accessories

    4) motors power wheels

  • Eric Carter

    This doesn’t look like a hybrid at all, just a diesel-eletric drive similar to what many vehicles with the high-torque requirements would use. If it was a hybrid then shouldn’t “batteries” be called out on that image? Hybrid implies two sources of power, which this does not. It’s closer to a train that a Prius or Volt.

    Assuming that picture, the power flow appears to be as follows:

    1) diesel fuel power engine

    2) engine turns generator

    3) generator powers electric motors/accessories

    4) motors power wheels

  • Mr. Sinister

    It’s not really a hybrid … it’s an electric bulldozer that happens to have an on-board diesel generator to supply the electric power. As the article points out, the dozer does not store power. There would be no point, since the battery storage capacity required to move such a machine would be enormous.

    The advantage of this configuration is that the diesel engine can be shut down when the dozer 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.

    Excellent idea from Catepillar. Far too little attention has been paid to the opportunities for improving efficiency in service vehicles, shipping, and heavy equipment. That’s where the low-hanging fruit is … and these are the sorts of applications that can tolerate the higher up-front costs, whereas hybrid price premiums are a significant barrier in passenger vehicles.

  • Mr. Sinister

    It’s not really a hybrid … it’s an electric bulldozer that happens to have an on-board diesel generator to supply the electric power. As the article points out, the dozer does not store power. There would be no point, since the battery storage capacity required to move such a machine would be enormous.

    The advantage of this configuration is that the diesel engine can be shut down when the dozer 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.

    Excellent idea from Catepillar. Far too little attention has been paid to the opportunities for improving efficiency in service vehicles, shipping, and heavy equipment. That’s where the low-hanging fruit is … and these are the sorts of applications that can tolerate the higher up-front costs, whereas hybrid price premiums are a significant barrier in passenger vehicles.

  • R.G. LeTourneau was doing this in 1950.

    Many large earthmovers are doing this today in very large equipment. Most large railroad (train) powerplants are diesel electric too. Kudos to the marketing folks for mis-informing those who do not know.

  • R.G. LeTourneau was doing this in 1950.

    Many large earthmovers are doing this today in very large equipment. Most large railroad (train) powerplants are diesel electric too. Kudos to the marketing folks for mis-informing those who do not know.

  • Paul Gunderson

    Diesel locomotives have operated around the world for 7+ decades. Now we have a group with the intelligence to use the torque of the electric motor in one of the most torque involved machines invented, DUH, imagine that.

  • Paul Gunderson

    Diesel locomotives have operated around the world for 7+ decades. Now we have a group with the intelligence to use the torque of the electric motor in one of the most torque involved machines invented, DUH, imagine that.

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