Posted on 02/20/2011 6:08:28 AM PST by saganite
So what will the FE be when driving across Nebraska at 80 mph?
What will be the FE when driving along favorite FS roads in the Rockies?
The article says highway mileage will improve but the primary advantage of a hydraulic hybrid is in stop and go driving. If the article is correct they could produce a vehicle with better fuel mileage in town than on the highway.
As to your question. If you drive your pickup 80 mph fuel economy isn’t something you need concern yourself with. ;^)
My ‘01 GMC Sierra 4WD gets about 18 mpg. It has 81,000 miles and has been trouble free.
My next truck MUST get better miles per gallon.
Mileage is better in stop-and-go driving than highway cruising because the hydraulic system captures energy normally lost during braking – which also saves wear on wheel brakes – and uses that energy to recharge pressure in the accumulator, in a process called regeneration. Engine power can also be used to regenerate pressure.
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Does anyone actually believe this? Is there a thermodynamic engineer in the house?
Now if the statement was that mileage IMPROMENT was better in stop-and-go traffic then it would make sense. As stated it is just nonsense.
Some hybrids actually do have higher EPA City milage ratings than Highway milage ratings. (The 2010 Prius was rated at 50 City/49 Highway.)
On some hydraulic hybrids, the engine will turn a pump to pump up the pressure in the accumulator while stopped, which is then released all at once when it accelerates.
This can be more fuel efficient than using the engine only to accelerate.
Hydraulic hybrids are best suited to large, heavy vehicles that make frequent stops. City busses and garbage trucks are the two ideal candidates. The reason is because you can store energy much more quickly in a hydraulic accumulator than you can recharging a bank of batteries.
A Ford F150 isn’t the most likely candidate, because at the smaller scale, the relative efficiency of the hydraulic system is lower than an electric hybrid.
No, it is most likely true. The most efficient hybrids have better fuel economy at slower speeds since wind resistance is low. Even in stop and go driving since the effects of braking and idling are almost negated.
It makes sense to me because in highway driving your engine will operate continuously whereas in stop and go driving the truck will accelerate from a start using the stored energy from braking. I’m not so certain it will be as dramatic as claimed but these things have been in development for a long time and the system is currently running on vehicles such as garbage trucks and delivery trucks. Mileage improvement there is from 25% to 50%. The hydraulic hybrid is much more efficient than an electric hybrid at capturing brake energy.
Ping
Just wait for those quick starts at -30...LOL!
Blown seals, ruptured lines, or just no go.
Does anyone actually believe this?
FEDEx, UPS, et. al. are checking on it now.
“The Navistar VT365 diesel engine, rated at 200 horsepower, is directly connected to the hydraulic pump, not a transmission. Computer controlled pumps and pressure control valves take hydraulic pressure stored in the on-board tanks (the tanks are like batteries in an electric hybrid vehicle) to power the rear axle. A pump at the rear axle recaptures energy during braking, converting the rotational energy into hydraulic pressure. There is no driveshaft linking the engine to the driven axle, so all of the diesel’s power goes in to producing hydraulic pressure.
In congested, low-speed urban driving, hydraulics efficiently recapture the vehicle’s braking energy. Eaton developed the system and claims that it is about 70-percent efficient at recapturing braking energy if measured on a round-trip basis. Since urban delivery vans stop a lot and often have limited high-speed runs, an efficient means of recapturing kinetic energy is critical to improving fuel efficiency. Of course, conventional vans don’t recapture any energy during braking, so these gains are important.
UPS’s HHV are still in the experimental stage, and are actually a product of a cooperative effort between the U.S. Environmental Protection Agency, Eaton Corporation, the U.S. Army, and Navistar International Corp. Before this current test, the team conducted an 18-month evaluation of a prototype’s performance and emissions on a UPS delivery route in the Detroit, Michigan area. Results showed that the patented hydraulic hybrid diesel technology achieved a 45- to 50-percent improvement in fuel economy and a 30 percent reduction in CO2 emissions compared with traditional diesel-powered vehicles. Results from this earlier test demonstrated that fuel economy was increased compared to a conventionally-powered diesel delivery van in three ways:
•Vehicle braking energy is recovered that normally is wasted
•The engine is operated more efficiently
•The engine can be shut off when stopped or decelerating.”
It works in city traffic just fine and no doubt mileage performance will be improved. But the city mileage will NEVER be as good as the highway mileage. Some of that braking energy is going to go to heat and is not recoverable. The efficiency of the hydraulic recovery system can never be 100%. it could approach it but it can’t reach it.
I’m not knocking the system - just the claim that city mileage is better than highway mileage.
Just imagine what happens when the high-pressure hydraulic system bursts, though....
I don’t think much of anything operates too effectively at -30. Certainly not me! However, I would point out that hydraulics have been proven at lower temperatures than that.
It probably won’t present as much problem as electric hybrids which pose a serious risk to rescue personnel in a crash scenario.
They're just different problems, not "less" or "more" problems. The kinetic energy of a bus is enormous; and with all that energy packed into a tank of hydraulic fluid, it would burst with impressive force.
Theory is great -- but they've got to make sure of the safety of these things. Shrapnel is not a friendly guest at a car wreck.
Well, I’m electrical and not thermodynamic, but the principle is actually very simple, and yes, it works.
VA Power has a huge lake in the mountains......at night when electrical demand is low, they pump water into the lake. In daytime, when demand is high, the water goes back down through turbines and generates power. It is a simple form of storing energy.
The Ford system is similar, except that it uses braking energy to then store in a hydraulic “battery”. The pressure in the hydraulic storage unit is then released to help accelerate the truck from a stop, saving fuel.
That’s why the system is best/most effective in city driving with a lot of stops and starts.
“What will be the FE when driving along favorite FS roads in the Rockies?”
What will be the FE when driving along roads in Texas, dodging magestic 8 point bucks?
Why must the Ford go into this? Government has done more to wreck our life and cars.
My 1st Ford truck was [1968] fixable. My current [2002] F-150 is great, but I can’t fix it. It has go goto the shop.
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