Hydraulic hybrid technology!

[sketron13]

So has anybody ever heard of this? Apparently it was thought up in the 1920's or 30's and a guy tried it successfully in the 70's. Now someone is using a 14hp lawmower engine in a 2,000lb car, 0-60 in 8 sec, 75 mpg!!!

They're using this stuff in big vehicles too, a Launch Assist system I think they call it. This would be an excellent idea for offroading as it provides loads of torque, and can be recharged when braking, and can be shut off once the hydr. pressure is built up. I'm in school to get my A/P mechanics license, and I'm going to try to talk them into letting us build a hydraulic hybrid subaru, maybe from a justy or hatch? What do you guys think?

 

Here's some links to the articles about it:

http://www.motherearthnews.com/library/1978_March_April/This_Car_Travels_75_Miles_on_a_Single_Gallon_of_Gasoline_

http://www.greencarcongress.com/2006/03/epa_and_univ_of.html

[scrap487]

thats a cool idea, if i had time money and place to work I'd consider doing something like that, but definately not with a subaru engine, because according to that first article(have yet to read the second) when they built their first vehicle using a 60hp vw engine the actual gas milage went down because it was too much power.

 

if i read it right, it works essentially like steam engines worked, except instead of heating up water to create pressure you are using a motor attached to a pump. I've also seen similar stuff done with compressed air.

 

also if you did build that, I think using a RWD car would be easier.... and possibly any chance for real smokey burnouts>

[rallyruss]

a justy motor might be a small enough power plant to pull it off. sounds like fun.

I deal with hydraulics at work. It seems complicated but its not all that hard to work with. If you can grasp electrical you will do great with hydraulic.

 

personally I would use a small Yanmar Diesel out of a little John deer mower. they already have pumps ect usually.

variable displacement pumps are the most eficient but also are the most veunerable to contamination in the hyd. system. just somthing to consider.

[jaacina]

I was thinking of using a small lawn mower type mower turning a generator which recharges a battery pack. Then have the battery pack powering an electric motor. http://www.motherearthnews.com/Alternative_Energy/1979_July_August/An_Amazing_75_MPG_Hybrid_Electic_Car

 

Just another option. Batteries and control might get expensive.

[bgd73]

That sounds cool. Linear flawed energy into fluid pressure. Awesome idea. For that small engine to gain more power than it normally would to gears is incredible!

[Mr Fishums]

Cool! Lets see someone do it with a justy!

[sketron13]

The one article said it could be done with $600 in over-the-counter parts. It completely makes sense, I think I'd put a hydraulic motor/pump at each wheel to capture all braking energy possible, and one at the small engine with a freewheeling unit. Interconnect all with the accumulator, and you've got it. Think about this: 4x4 Mid-engine/hydraulic hybrid justy pushin 50cc, maybe 10 or 15 horses, gettin 75mpg. It's going to happen!

[robm]

Hybrid electric makes more sense. Hydraulics are inherently less efficient than electric. A hydraulic pump is about 90% efficient, a hydraulic motor about the same, the combination is about 80%. An electric generator/motor combo is about 90% efficient. Direct drive might be a bit better than a hydraulic, in a 2WD, same or worse in a 4WD.

Regenerative braking "recycles" about 15% of the energy put into the vehicle, a lot less than you would expect.

 

The huge torque mulitplication available is great for burnouts and offroad use, though. And the ability to store energy means you don't need the 100 HP engine that normally runs around 15 -20 HP at cruise. But the hybrid can be built to give these advantages, too.

 

The one advantage the hydraulic has is no batteries. But I am not sure what the energy storage density of an accumulator is. Maybe batteries are an advantage!

 

Your 50 cc Justy might be OK in the bush, but it would be little slow on the road. It takes about 15 HP at the wheels for a little shoebox type vehicle to run down the road at 50 mph, so your 8 HP (at the wheels) might make 40?

[Mr Fishums]

Hybrid electric makes more sense. Hydraulics are inherently less efficient than electric. A hydraulic pump is about 90% efficient, a hydraulic motor about the same, the combination is about 80%. An electric generator/motor combo is about 90% efficient. Direct drive might be a bit better than a hydraulic, in a 2WD, same or worse in a 4WD.

Regenerative braking "recycles" about 15% of the energy put into the vehicle, a lot less than you would expect.

 

Your 50 cc Justy might be OK in the bush, but it would be little slow on the road. It takes about 15 HP at the wheels for a little shoebox type vehicle to run down the road at 50 mph, so your 8 HP (at the wheels) might make 40?

 

And 100% orange juice is made with 40% fresh squeezed kittens!

Tell me, how do your guesstimation calculations justify your 15% on regenerative braking?

 

I'm just curious where you got that from, because I've raced in the tour de sol for four years now, with three different full electric vehicles. All of which used regenerative braking. I would like to know where you got that approximation from and how it was conducted.

 

Peace, Fishums

[sketron13]

Batteries = heavy + expensive Plus you have to plug in the hybrids that get over 50mpg. And what car over 15 yrs doesn't have electrical problems, or components going out, etc. I've worked around hydraulic machinery older than I am running 20 hours a day and they usually run flawless. Hell, you could maybe even figure out a way to retrofit existing gasoline or diesel engines with some sort of a helper launch assist pump/motor system like the one article talks about doing. There's definitely money to be made from this from someone...

[WAWalker]

If there was money of any amout to be made, the automotive makers would be all over it.

 

Couple of problems.

It is an 1,800 pound car. Didn't see any info about on board fuel capacity. Are they just using the lawn mower fuel tank? Add a fuel tank so you don't have to fill up every 75 miles, spare tire, suitcase, and a friend or two. Build a safe structuraly sound body.......add 4WD...........not an 1,800 pound car anymore.

 

Up to 70 mph in NO WIND conditions. I've already got one of those.

 

The majority ain't going to buy it.

 

Very interseting though.

[sketron13]

For the weight, they would have to switch to using alot of composites. As for the companies all over it, read those articles and you will see that they're already trying it extensively in China. I just think everyone in this country was thinking in the electric hybrid box until now. One more advantage over batteries though, high-pressure hydraulic fluid called skydrol is organic and not toxic. They say it will eat through the soles of your shoes, but it's safe to drink (used in airplanes). Show me a lead-acid, ni-cad, or lithium ion battery that can claim that!

[scrap487]

If there was money of any amout to be made, the automotive makers would be all over it.

 

Couple of problems.

It is an 1,800 pound car. Didn't see any info about on board fuel capacity. Are they just using the lawn mower fuel tank? Add a fuel tank so you don't have to fill up every 75 miles, spare tire, suitcase, and a friend or two. Build a safe structuraly sound body.......add 4WD...........not an 1,800 pound car anymore.

 

Up to 70 mph in NO WIND conditions. I've already got one of those.

 

The majority ain't going to buy it.

 

Very interseting though.

 

A subaru doesnt weigh much more and I'm pretty sure a justy is under 2000lbs. Weight doesnt have a whole lot to do with it, once you get going and are cruising at a constant speed weight shouldnt really affect your economy. Add a couple friends some luggage to any car, you aint gonna near as you had before. Anyways, it'd make a cool project, I'm gonna build a bike later this spring.

 

As for advantages over electric hybrids, battery technology is decades behind modern electronics/technology, they're coming out with new and better stuff but in reality theres still a lot of work to be done to get something truly economical.

[WAWalker]

Well maybe I'm just a pessimist. But in reality, people have for years been spending money to try and save money, and usually spend more than they will ever end up saving. Pay extra for a hybrid car so you don't have to pay at the pump......................so your still spending the money. But I guess you do have the warm fuzzy feeling of saving the world, thats worth somthing.

 

I love the idea of solar power. Looked into the cost of running an entire home on solar. Not exactly cost effective. At the time the estimate was 30-40 years for a system like that to pay for itself. Don't remember how long the panels last, but it's not forever, so they will need to be replaced. Batteries need to be replaced........................................good idea but in my world the math don't work.

[robm]

The 15% figure came out of work done years go by Ford. I think I saw it in the IEEE magazine, or the ISA, or maybe SAE. This was an overall improvement, based on the way a car is used in the real world, not on some imaginary test track.

 

It makes sense if you think about it. At speed, most of the energy is being sucked out of the car by aerodynamic and other forms of drag and resistance. The energy stored in the car is only the kinetic energy, mv^2/2. There isn't much of that in a small, light car.

 

Maybe they can do better now, with better technology all around. But I bet it is still close.

 

As an example, the 2005 Civic Hybrid vs the 2005 Civic is 25% better on the "city" rating, and 16% better on the "highway".

 

http://www.epa.gov/fueleconomy/5yearhigh-low.htm

 

When you consider the "highway" test still has a lot of stop and go, it is NOT just steady state on the highway for hours on end, you can see that the improvement may well average out to 15% - depending on how you use the car.

 

You sunracers use regen braking because it doesn't cost anything to implement - just a bit more skull sweat for the programming, and maybe a few more switching transistors to turn the current around. On a purely highway trip, it probably doesn't save a lot of energy, but every little bit helps when racing. If racing around town, or in a stop and go situation, it seems to be good for 25% - if your car's characteristics are similar to the Civic Hybrid.

[LPGsuperchargedBrumby]

i like the idea of this system but some of the things in it or claimed don't make sense to me. it would work well in stop/go driving, but unless you have a huge accumulator, a long hill or even a strong steady headwind on a long drive would drain the reserve pressure in the accumulator faster than the little engine could restore it.

the regen' braking i did like, and you should be able to get more than 15% back as im pretty sure the limit on batterys is how fast they can be charged, hydraulic accumulaters don't care how fast fluid gets pumped into them,only the max pressure they can tolerate.

 

im a M&D Engineer trained in (among other things) hydraulic system design and in my professional opinion:confused: the the cost of the pump,hyd' motor, accumulator and valving for a setup like this would suk the big na-na

[eponodyne]

Hmmm.... I wonder if the Justy CVT could be used with a pump/accumulator system to keep everything up to specs... Ya folla? Driving is a continuously variable process, after all.

[suba]

Check this out.

 

http://seniordesign.engr.uidaho.edu/2004_2005/dumpsterdivers/

 

I worked on this project last year. The system was built using parts ford donated from a navigator test vehicle that used a similar system. The original intent was to adapt the system for use on garbage trucks (bigger vehicles that start and stop often are the most efficient use of the system) but funding was cut so it was never continued this year.

[nipper]

So has anybody ever heard of this? Apparently it was thought up in the 1920's or 30's and a guy tried it successfully in the 70's. Now someone is using a 14hp lawmower engine in a 2,000lb car, 0-60 in 8 sec, 75 mpg!!!

They're using this stuff in big vehicles too, a Launch Assist system I think they call it. This would be an excellent idea for offroading as it provides loads of torque, and can be recharged when braking, and can be shut off once the hydr. pressure is built up. I'm in school to get my A/P mechanics license, and I'm going to try to talk them into letting us build a hydraulic hybrid subaru, maybe from a justy or hatch? What do you guys think?

 

Here's some links to the articles about it:

http://www.motherearthnews.com/library/1978_March_April/This_Car_Travels_75_Miles_on_a_Single_Gallon_of_Gasoline_

http://www.greencarcongress.com/2006/03/epa_and_univ_of.html

 

 

Ford was going to do this on thier f250's but they droped it because it was expensive, noisey and heavy. Hydraulic pumps are not quiet.

http://www.designnews.com/article/CA220671.html

 

 

nipper

[NorthWet]

...the regen' braking i did like, and you should be able to get more than 15% back...

The point with regen braking is not that the efficiency is giving you the 15%-ish return, but the usage is doing that. If you hopped on the highway, drove 200 miles/Km/leagues/whatevers, then got off of the highway and let the car coast to a stop and did not touch your brakes, you would have 0% regen braking. (Extreme example, but to make a point clearer.)

 

In other words, most of the used energy is lost to other resistance and not to the braking action that would allow regen braking. So, regen braking might return 15% of TOTAL energy usage, more probable in in-town driving.

[LPGsuperchargedBrumby]

i understand your example, but how many many times do's someone drive a car and never use the brakes, especialy in town stop/go type driving