UPS is First in Delivery Industry to Test Hydraulic Hybrid Vehicles: 50% Better Fuel Economy and 40% Lower Emissions
In partnership with the US Environmental Protection Agency, UPS will begin testing a small fleet of hydraulic hybrid delivery trucks in the United States. The new vehicles can achieve 50-70% better fuel economy, a 40% reduction in greenhouse gas emissions, and pay for their extra expense in less than 3 years.
UPS will field two hydraulic hybrids in Minneapolis, MN, in early 2009 and an additional five hydraulic hybrid trucks will be deployed later in 2009 and early 2010. Although this sounds like a tiny fleet, keep in mind that this is the largest scale commercial test of hydraulic hybrids ever conducted.
The UPS hybrid hydraulic truck is a standard-looking 24,000 pound package car, with an EPA-patented diesel series hydraulic hybrid drive attached to the rear axle.
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In a series hydraulic hybrid, the conventional drivetrain is replaced with a hydraulic system that stores energy by compressing gas in a chamber using hydraulic fluid. It works in much the same way that a hybrid electric car does — a small, efficient motor generates power which gets stored for later use — only, the way energy is stored in a hydraulic hybrid is in a pressurized chamber rather than in a battery.
The hydraulic hybrid drivetrain eliminates the need for a conventional transmission and increases fuel economy in three ways:
- A large amount of the energy that is otherwise wasted in braking can be recovered to pressurize the hydraulic fluid.
- The engine operates much more efficiently — similar to a hybrid electric car, only without the bulky batteries
- The engine can easily be shut off and instantaneously restarted during regular driving — such as when the vehicle is slowing down or stopped at a light.
UPS has been developing what it calls its “green fleet” over the last several years and currently has more than 1,600 low carbon emissions vehicles including electric, hybrid-electric, compressed natural gas, liquefied natural gas, and propane trucks.
Although this is a small step, I applaud UPS for testing the waters. Hopefully others will join in quickly.
Source: UPS press release
Image Credit: UPS
Who actually makes these hydraulic hybrid vehicles? Do they have any plans to produce passenger vehicles with the technology? From how you describe them, they already sound like they are a sure thing. So where are the non-UPS hydraulic hybrids? Cranky, cynical minds want to know.
Carbon, my friend, your cranky cynical mind has jumped several steps ahead of the testing process.
We have another post on Gas 2.0 about a company called Artemis who has been working on a passenger car version of the hydraulic hybrid. You can see it here:
http://gas2.org/2008/06/13/hydraulic-hybrid-technology-could-rival-batteries/
It is still a new technology and has to be road tested before it can be implemented at full-scale. But my bet is that it will take hold in other areas soon too.
Just one small correction to your story. Your quote “hydraulic system that stores energy by compressing hydraulic fluid in a chamber.” Hydraulic fluid is non compressible as is any liquid. Sorry;)
You’re right Jim. I guess the more accurate term would be “pressurizing” for those that understand the difference. I’ll change it.
I studied these a while back. The actual energy is stored as compressed air. When the brake pedal is depressed, a hydraulic pump kicks in powered by the kinetic energy of the truck and it compressed airs as the truck comes to a stop (or slows) and then, when the brake is released, the increased pressure in the air tank is used to drive the fluid the other way (to move the truck).
This is way cool technology. As long as the air compression tank is well insulated, it’s a very efficient system with little energy losses. (The insulation is needed to prevent loss of energy due to the heat of compression, i.e., when you compress air, it gets hotter…losing that heat lowers the pressure –> lost energy.)
From what I understand it’s most amenable to trucks that do a lot of starting and stopping, particularly garbage trucks, mail trucks, buses, and delivery trucks. Any car/truck that regularly gets caught in big-city traffic could use this, however. All the technology is already there too and well understood (Hydraulics is a very mature technology…if you’ve ever seen a backhoe working, you’ve seen hydraulics in action).
-Tim
Typo. The third line above should read:
“truck and it compresses air as the truck …”
Tim,
From the EPA website:
“The high pressure accumulator stores energy as a battery would in a hybrid electric vehicle using hydraulic fluid to compress nitrogen gas”
The nitrogen gas is compressed in a high pressure accumulator (chamber) and then, as the pump/motor uses the energy stored in the compressed gas, the low pressure hydraulic fluid outflow from the pump/motor is sent back to the low pressure chamber for reuse later on.
I’ve made a few tweaks in the wording of my post to make this clear. Thanks.
Wow, that is pretty cool. Nice!
Jiff
http://www.anonymity.cz.tc
UPS, that is nice, I choose it
Nick,
The tweaks definitely make it easier to understand for any newbies out there.
-Tim
P.S. How are you feeling after your accident?