Hydraulic Hybrid

[cjolley]

You just never know what will turn up.

http://www.pressroom.ups.com/mediakits/factsheet/0,2305,1315,00.html

UPS to Test New Hydraulic Hybrid Technology
UPS has been testing and deploying different types of automotive technology for decades looking for ways to enhance the environmental performance of our fleet. That continues today with our fleet of over 1,300 alternative fuel vehicles including hydrogen, hybrid electric, propane, compressed natural gas and liquefied natural gas vehicles. UPS is now adding a new kind of technology to that list -hydraulic hybrid technology. UPS to test the World’s First Full Hydraulic Hybrid Urban Delivery Vehicles
The U.S. Environmental Protection Agency (EPA), UPS, Eaton, International Truck and Engine, and the U.S. Army are testing the world's first full hydraulic hybrid urban delivery vehicle.
Hydraulic hybrid technology, which promises significant emissions reduction and fuel economy, will become the power source for two vehicles that look like traditional brown UPS delivery trucks. The nature of our business, which requires vehicles to make frequent stops-and-starts, makes UPS an ideal partner to test this new automotive technology since the act of applying the vehicle’s brakes increases the hydraulic pressure, or energy needed, to propel the vehicle without utilizing the diesel engine.
UPS first learned of this opportunity in 2003 when the company was working with the EPA and DaimlerChrysler to build and test hydrogen fuel cell vehicles.
How Hybrid Hydraulic Technology Works
Hybrid hydraulic technology includes two power sources that propel the vehicle - a small fuel-efficient diesel combustion engine and hydraulic components. Hydraulic hybrid technology replaces a conventional drive train with a hydraulic one, which eliminates the need for a mechanical transmission and driveline.

Fuel Economy & Emissions Reduction
The features of this vehicle combine to make a highly cost-effective hybrid with the following benefits:

• 60-70 percent improvement in fuel economy in laboratory tests
• 40 percent reduction in CO2 emissions

The fuel economy improvement comes from three things:

• Running the engine at the optimum efficiency point as much as possible
• Regenerative braking, which captures and stores a large portion of the energy normally wasted in vehicle braking. The stored energy is used to help propel the vehicle during the next vehicle acceleration—reducing fuel consumption and enabling the vehicle to operate more efficiently.
• These vehicles can store the energy from the hydraulic power, even after the vehicle is turned off. This storage may allow the vehicle to start with this energy, instead of relying on the engine to propel the vehicle.

Additionally, since a hydraulic hybrid vehicle is mechanically based, as opposed to traditional HEV vehicles which are electrically based, troubleshooting problems and regular vehicle maintenance should be easier, more efficient, and thus more economical.

[MultimediaMan]

Viscious Drive has been around a long time: there are some significant mechanical losses, but the nice thing about it is that the loss is extremely easy to predict.

The Viscious Drive also "scales" well both up and down.

I see a couple of problems though:

The assertation that they can store pressure in an accumulator is correct, they fail to mention that significant energy will be lost as the fluid cools at rest. Viscious Drive systems generate significant heat (just put your hand on a common hydraulic floor jack after lifting a vehicle quickly). Thus, to reach top efficiency, they have "run up" to temperature for best performance.

I really don't like that they have put the pressure reserviors on the outside of the vehicle frame beams: a broadside crash could be a messy one.

I am wondering again about Steam Power...

[cjolley]

To minimize hydraulic drag they should use LARGE hard lines for the fluid.
Hydraulic drag scales* as the 4th power of the radius!



*As I recall from Physics I in 1970 anyway

[Brian Ellis]

I'm with MMM in that the thermal energy losses would be more significant than is suggested. See the big cooling fans in the schematic! This is the same problem as with pneumatic vehicles. It also assumes that the braking energy is from the rear wheels. The front wheels normally absorb ~60-70% of the braking energy as the vehicle centre of gravity is thrown forward.

Then there is efficiency: the best hydraulic pumps and motors have an overall energy efficiency of 85% each, so the best diesel motor to wheels efficiency would be 72%. An electric system would be >90%. The difference is because hydraulic pumps and motors have much more internal friction than their electric counterparts.

Also, it is not a true hybrid, any more than a diesel-electric vehicle. A true hybrid applies energy to the driving wheels from two sources, by definition. A true hybrid car is driven by a combination of an ICE and an electric motor. Neither one source nor the other is sufficient to drive the vehicle adequately under all conditions. If the energy to the wheels comes uniquely from a single source, be it an electric motor(s) or a hydraulic one, it is no longer hybrid.

[cjolley]

Well, they say "60-70 percent improvement in fuel economy in laboratory tests"

Even allowing that the real world savings might only be half of that, the change would pay for it's self in short order considering the way they are driven in some markets.
ie drive 100 meters, stop, drive 50 meters, stop, drive 100 meters, stop, drive 25 meters, etc, etc. All day long, every day.

And hydraulic technology is very well understood, so they can wait to go electric when that is farther along. Particularly battery tech. If they were electric the batteries would undergo FAR more cycles in the vehicles life than in a regular hybrid car.
I wonder if that is why taxis, which would seem to be a natural fit for hybrid, are not rushing out to convert.

A true hybrid applies energy to the driving wheels from two sources, by definition.

I don't get it. This system can provide energy to the rear wheels using the diesel to drive a pump to provide hydraulic power or using the accumulators to provide hydraulic power. What difference does it make that the "drive shaft" is pipes carrying pressurized fluid versus a shaft carrying torque?
Maybe it does. Please explain.

PS Why aren't buses being converted to hybrid of some type at a higher rate. This REALLY seems like a good fit to me.

[Brian Ellis]

I wonder if that is why taxis, which would seem to be a natural fit for hybrid, are not rushing out to convert.

They are:

MAYOR BLOOMBERG ANNOUNCES TAXI FLEET TO BE FULLY HYBRID BY 2012

PlaNYC Goal for Greener Taxis Will Reduce Emissions from Cabs By 50% in the Next Decade

Yahoo! Donates 10 Hybrid Taxis Which Will Replace Existing Gas-only Powered Cabs

Mayor Michael R. Bloomberg today announced that as part of PlaNYC, the Taxi and Limousine Commission (TLC) will implement new emissions and mileage standards for yellow taxicabs that will lead to a fully hybrid fleet by 2012 - the largest, cleanest fleet of taxis on the planet. The new standards will be phased in over a four-year period and will reduce the carbon emissions of New York City's taxicab and for-hire vehicle fleet by 50% during the next decade, and will also save individual operators an average of $10,000 a year in fuel costs. Also today, internet giant Yahoo! donated 10 hybrid taxicabs to fleet operator Team Systems in recognition of New York's leadership in reducing greenhouse gas emissions. The Mayor was joined at the announcement by TLC Commissioner Matthew W. Daus, Councilmember David Yassky, Yahoo! Network Division Vice President of Marketing Patrick Crane, American Lung Association President Louise Vetter, and other industry and regulatory leaders.

"In PlaNYC, we set aggressive goals for the taxicab industry and today we're going to begin meeting those goals," said Mayor Bloomberg. "Implementing tougher standards for the more than 13,000 taxis in this City will provide the same clean air benefits as removing 32,000 privately owned cars from our streets, which will significantly reduce the air pollution that causes childhood asthma. This will also decrease the fuel costs for taxi drivers, making this a win for the public and operators alike. I'd like to thank Yahoo! for their commitment to the environment and for recognizing our efforts in addressing global warming by donating these cabs."

On Earth Day, Mayor Bloomberg outlined PlaNYC, a series of 127 proposals aimed at helping New York meet the challenges of adding nearly one million people to the City's population between now and 2030, while at the same time reducing the City's greenhouse gas emissions by 30%. The Ford Crown Victoria, the current workhorse of the taxicab fleet, achieves only 14 miles per gallon (mpg). After October 2008, all new vehicles entering the fleet must achieve a minimum of 25 mpg (based on EPA city surface street ratings), and after October 2009, all new vehicles must achieve a minimum of 30 mpg. When fully implemented, the new standards are expected to reduce carbon emissions by more than 215,000 tons. Currently there are only 375 hybrid vehicles in the City's taxi fleet. By October 2008, the number of hybrids in the fleet will triple. The phase-in for the City fleet to become completely hybrid is as follows:

*
October 2008 - 1000 yellow hybrid taxicabs;
*
October 2009 - 4000 yellow hybrid taxicabs (30% of the fleet)
*
October 2010 - 7000 yellow hybrid taxicabs (53% of the fleet)
*
October 2011 - 10000 yellow hybrid taxicabs (76% of the fleet)
*
October 2012 - all yellow taxicabs will be hybrid (100% of the fleet)

"We expect these new standards will save 22 million gallons of fuel in the first year, and that is only the beginning of what we will be able to accomplish," said TLC Commissioner Daus. "Thanks to Mayor Bloomberg's bold vision laid out in PlaNYC, the New York City taxi fleet's carbon footprint will be lighter than at any point in its 100-year history. The environmental meter is running, and our efforts are paying the fare for a healthier tomorrow. We appreciate Yahoo!'s support and their gift of ten clean, green taxicabs."

It is estimated that increasing fuel efficiency from 14 mpg to 30 mpg will save the average taxi operator more than $10,000 per year. The new fuel efficiency standards will be accompanied by clear guidelines for evaluating the vehicles emissions performance, and for new vehicle specifications that will ensure both passenger comfort and driver safety. Wheelchair accessible taxicabs being brought into service will be exempt from the new fuel economy requirements.

"In the face of climate change, the old ways of doing things are no longer good enough. Mayor Bloomberg's PlaNYC is an absolutely essential step toward reversing course on climate change and air quality, and I will work as hard as I can to help turn the Mayor's plan into reality," said Councilmember David Yassky. "I applaud Mayor Bloomberg for acting now to turn New York City taxi cabs from part of the problem into part of the solution. New York City's 13,000 taxi cabs will still be yellow on the outside, but soon they will be green on the inside."

As part of its "Be a Better Planet" program, Yahoo! donated ten hybrid Ford Escape taxicabs to operator Team Systems. The cabs will be used to replace gasoline-only powered Ford Crown Victoria vehicles, saving tens of thousands of gallons of fuel over a taxicab's service lifetime, and reducing carbon emissions by more than 16 tons per vehicle each year. The vehicles being donated today get approximately 36 mpg (city streets). Yahoo! kicked off the "Be a Better Planet Challenge" in Times Square last week.

"Yahoo! applauds Mayor Bloomberg's aggressive PlaNYC initiative to build a greener, greater New York City," said Patrick Crane, vice president of marketing, Yahoo! Network Division. "As a company focused on protecting the environment, we found it only fitting to award New York with a fleet of hybrid taxis as part of our 'Be a Better Planet' campaign, which gives people across the country specific ways to take green actions in their hometowns. We challenge other cities across America to follow New York's example as Yahoo! searches for the greenest city in America."

"Putting more clean cabs on New York City streets is an important step in our fight to improve air quality, especially for the one million asthmatics in our city," said Louise Vetter, President and CEO of the American Lung Association of the City of New York. "By turning our yellow cabs green, we can put New York City miles ahead on the road to clean air."

In addition to the PlaNYC speech on Earth Day, New York City hosted the historic C-40 Large Cities Summit last week. During a keynote address to the Summit on Tuesday, Mayor Bloomberg announced that New York is joining the Climate Group, and on Wednesday he announced that New York City would participate in an initiative sponsored by the Clinton Foundation to reduce carbon emissions from buildings.

The word hybrid means a combination of items. A mule is a hybrid of a horse and a donkey. A hybrid tea rose combines the advantages of two basic but very different rose plants. A car with an engine and a mechanical transmission is not a hybrid. A car with an engine and an electrical transmission is not a hybrid. A car with an engine and a hydraulic transmission is not a hybrid. A car with an engine AND an electric or hydraulic motor, BOTH of which drive the wheels IS a hybrid.

PS Gillig produce a true hybrid bus, as do some European makes, but most so-called hybrid buses are simply diesel-electrics.

[cjolley]

Thanks for the info.
BTW Tulsa, 90 miles from here, has at least one of the Gillig Hybrids.
Oklahoma City probably uses some kind of extra fuel using bus to help support the oil industry.