Being in Belgium in November for a truck show may or may not be your cup of tea/mug of Java, but Mercedes is at least doing its best to make the "Trailer 2011" exhibition interesting. The truck design world moves at a glacial pace compared to the consumer automobile business, and new models have to provide serious and significant commercial improvements if they are to be accepted by the trucking fraternity. Coming off the back of the well-received launch of its new Actros heavyweight tractor unit, Mercedes brought along a trailer concept design that aims to match and extend the significant commercial and environmental advantages of that unit. It looks cool, too.
There's no getting around the fact that trucks are big square boxes that take a lot of energy to plow through the air. The turbulence you feel when overtaking one on the highway is ample evidence of that.
Mercedes has managed to reduce the frontal wind resistance of the Actros tractor unit by 15 percent, through 2,600 hours of wind tunnel testing. The results can be seen clearly on the front face of the unit, which sports a number of subtle winglets, a plate, and channels to control airflow - the influence of all those millions spent on Formula 1 aero research, no doubt.
The logical next step is clearly to apply the same rigorous wind-tunnel work to the trailer half of the equation, and that's exactly what Mercedes has done. The interior dimensions of the trailer have to be maintained, of course, so a front air dam reduces the distance between tractor and trailer. The application of a number of precisely-calculated curved panels to the outside and underneath of the trailer channel air to a striking rear diffuser. In addition, there is a 400-mm (15.75-inch) extension to the rear in the form of a "boat-tail," that reportedly brings extensive aerodynamic benefits.
In total, Mercedes claims an additional 18 percent wind resistance reduction in the tractor-trailer combo, which should equate to a five percent reduction in fuel use. For the average year of a busy trailer, that represents 2,000 liters (530 US gallons) of fuel and an astonishing 5 tons (4.5 tonnes) of CO2.
The trailer is still a concept at this stage, since the extension at the rear will require a change in legislation. The reported benefits are so significant, however, that this may be achieved in due course.
The rear extensions also need to be designed to either fold back or otherwise collapse when the truck is moving back to a loading dock to load or offload its cargo.
To bad that the German engineers spent all their time at the wind tunnel and did not spend any time out in the world talking to truckers or even going online to research movable fairings. The Japanese engineers patented designs for a movable fairing for high speed trains and the same approach would work for trucks.
re; professore While I find the spray kicked up by trucks massively unpleasant when passing or being passed by a truck in wet conditions, I do not find it to be excessive given the amount of rubber on the road. How much are you willing to pay to reduce the spray from your car.
re; 2VT Given that most electric Hybrid systems will not pay for themselves over a reasonable length of time and the fact that the batteries are an ecological disaster, I\'m not disappointed in slow sales.
Overheated tires and brakes will kill far more people than the thrown rocks and wet weather spay.
Customer resistance to the design was high, some sources say fewer than 800 were built.
Apparently Peterbilt buyers were much more resistant to change than Kenworth buyers. The 1985-2007 Kenworth T600 was an almost immediate success, even though it only almost, but not quite, reached 8 MPG in its initial version.
The way to gauge the efficiency of cargo transport is in ton-miles per gallon, or ton(metric)-kilometers per liter.
Weight times distance divided by fuel used. (WxD)/F
A very slick but underpowered truck may be able to get a high unloaded MPG, but load it up and it\'ll do worse (WxD)/F than an aerodynamically \"dirty\" truck with a huge but under-stressed engine.
It\'s worked for aircraft, the Lockheed Constellation got very good efficiency for its time by using four of the biggest radial engines available. They never had to work hard and (once the bugs were worked out) could run longer between overhauls than smaller, higher stressed engines on other aircraft.
Perhaps, Mercedes should team up with ATDynamics since they already have a proven commercial product already streamlining thousands of non-aerodynamic trailers?...
FYI - In the US there is a law to allow for a 5 foot aerodynamic extension so long as you\'re not carrying cargo. Europe should get on board updating their old laws.