Diesel Hydraulic Delivery Truck Unveiled
The Environmental Protection Agency recently unveiled a hybrid diesel UPS delivery van that combines a high-efficiency diesel engine with a hydraulic propulsion system, which replaces the vehicle's conventional drivetrain and transmission. Such a vehicle could reduce the fuel costs of package delivery services like UPS by as much as 70 percent and cut harmful emissions.
In laboratory testing, the hybrid achieved a 60 percent to 70 percent improvement in fuel economy and a reduction of more than 40 percent in emissions, versus current UPS trucks. The EPA and UPS plan to conduct real-world testing this year.
A hydraulic hybrid has several advantages. One is that it can accept and deliver huge amounts of energy quickly, which batteries cannot. And its storage ability does not degrade over time, which is a fact of life with batteries available today. Generally speaking, though, hydraulic systems do not store as much total energy as an electrical battery does, because the storage tanks are bulky.
A hydraulic hybrid is more specialized than the gasoline-electric hybrids sold today. It works better on heavier vehicles, and in stop-and-go traffic; backers say the ideal vehicle for this system is a garbage truck, but that it could work well in vehicles as small as S.U.V.'s.
In the series hydraulic hybrid diesel, a high-efficiency diesel engine is combined with a unique hydraulic propulsion system, replacing the conventional drivetrain and transmission. The vehicle uses hydraulic pumps and hydraulic storage tanks to store energy, similar to what is done with electric motors and batteries in hybrid electric vehicles. In this design, energy is stored in a series of pressurized tanks, rather than in nickel-metal hydride or lithium-ion batteries; the energy moves not as high voltage current in copper wires but as hydraulic fluid pressurized to thousands of pounds per square inch. Fuel economy is increased in three ways: vehicle braking energy is recovered that normally is wasted; the engine is operated more efficiently; and the engine can be shut off when stopped or decelerating.
The U.P.S. van has four "accumulator tanks" of 22 gallons each which can be pressurized as high as 5,000 pounds. When fully charged, the system holds 2,000 horsepower-seconds of energy, according to Benjamin M. Hoxie, engineering manager for hydraulic hybrids at Eaton, an automotive supplier that built the prototype, using technology developed by the E.P.A..
When the truck is in operation, its diesel engine, running at constant speed, runs a pump to fill the storage tanks with fluid. The tanks contain nitrogen gas to When the driver presses on the accelerator, pressurized fluid is released from the high pressure tank and routed to the pump. The pressurized fluid pushes a piston down in its cylinder, recycling some of the energy to turn the vehicle's wheels.
The company says that because the diesel engine runs at constant speed, it will have a head start in meeting the stricter pollution standards that take effect in 2010.
At the introduction of the U.P.S. truck, Eaton announced that by next year it would commercialize a related technology, a "hybrid launch assist," which could be retrofitted on existing vehicles. It would capture braking energy and deliver it to the wheels again when it was time to accelerate.
EPA, UPS unveil hybrid delivery truck
EPA Unveils Unique Hydraulic Hybrid Diesel Delivery Truck with UPS, International Truck and Engine, Eaton and U.S. Army, press release, June 21, 2006
A New Wrinkle in Hybrids Does Away With Batteries, Matthew L. Wald, NY Times< June 26, 2006
All they have to do is replace the hydraulic motors in this vehicle with back to back hydristors and they would double the mileage
http://www.hydristor.com/
Posted by: Scott Makowski | July 02, 2006 at 02:56 AM
lol. As a former UPS weekend driver, I can only imagine what the companys mitigation approach is. We literally ran trucks that had the wheels falling off and had something like five modern automatic trannies in our entire fleet at the hub. Everything else was old 1980 something warhorses with all sorts of problems.
Hopefully they take this seriously.
Posted by: chris_sendak | July 02, 2006 at 03:24 AM
This is a terrifically elegant use of hoses and pumps. Imagine driving a big truck over a rolling road. From the top of each hill it coasts almost to the top of the next hill, and justs need a little engine push to get over the top before coasting down again. That's what this hydraulic hybrid should do. A heavy vehicle with lots of stops would get a big win from this. A garbage truck would probably gain the most -- a heavy load with ten yards between stops, all day long. And think of a city bus, instead of roaring and straining from each stop, being silently propelled to cruising speed by a big deflating balloon.
I hope it works.
Posted by: inDC | July 02, 2006 at 10:49 PM
Anyone know how quiet these things are? I get woken up by garbage trucks and night time street sweepers at least once a week.
Posted by: marc | July 03, 2006 at 03:44 AM
I get woke up by garbage trucks also. The noise of garbage trucks is largely made by the mechanical noise of compacting the gargage and the back up beepers. No propulsion system is going to solve these problems.
Posted by: Jim from The Energy Blog | July 03, 2006 at 09:50 AM
A large part of the noise I hear is engine noise and the squealing of air brakes. Both of those noises should be reduced or eliminated. Yeah, the compaction noise is a necessary evil.
Posted by: Bde2200 | July 03, 2006 at 11:02 AM
Wouldn't a "hydralic" system have to run off of a fluid by the classic definition?
Not that this isn't cool; but it needs a more appropriate name.
Posted by: Justin Thibault | July 14, 2006 at 08:41 AM
I mean, uh, "Hydraulic" - sorry 'bout that.
Posted by: Justin Thibault | July 14, 2006 at 08:42 AM
I think everyone should just buy insulating concrete form concrete homes so the noise of a bomb going off would be nothing more than a whipser. Then they could just make the truck efficient and worry about noise later. But the problem with ICF homes is we all like brick and stick homes that will only last 30 or 40 years. ICF would last centuries and would save us money, cheaper to cool and better insulating qualities when it comes to sound. Just another way the United States is being left behind by the rest of the world.
Posted by: Sean | July 15, 2006 at 11:54 PM
Hello from across the pond.....
I think everybody needs to look a little deeper, this technology really hits alot of bells in one bang for your buck.
We have developed a Desiel Particulate which has a totally controlled Regeneration process (REGEN) entirely indepenent of the ehxaust temperature.
Technically this means we CAN achieve even better overall results in extended Urban Drive Cycles. In London the average Bus speed is below 7mph and alternative exhaust dependant technologies become blocked.
So finally, where we're all heading is the RIGHT direction.
Posted by: Peter Kukla england | August 18, 2006 at 06:25 AM
Hi just a quick not to say we are on the lookout for talented hydraulics engineers. If your interested we have vacancies on http://www.ukengineeringrecruitment.net/ or just email me if interested
Many thanks for your time
Steve
Posted by: steve | March 26, 2007 at 06:25 AM
Just a quick heads up tp say we are looking to recruit top talent within the hydraulics field, we have vacancies at http://www.ukengineeringrecruitment.net, contact me for more info. Thanks for you time
Posted by: steve | July 04, 2007 at 07:54 AM
What's the latest; other than the delivery van I see nothing recent (and no word on test results from the van)?
Posted by: Joe | January 29, 2009 at 01:20 PM