The hydraulic hybrid may not be grabbing headlines, but it’s a solid technology with a potential future in heavy-duty vehicles. Vehicle manufacturers are considering it for next-generation garbage trucks, school buses, and delivery vans. Caterpillar has already unveiled it in an excavator and PSA Peugeot Citroen is working on a hydraulic hybrid automobile that could hit the streets by 2016. Chrysler Corp. and Ford Motor Co. have talked about it, as well.
To be sure, makers of electric hybrids, such as the Prius and Volt, aren’t looking for it in their rearview mirrors yet. But the technology offers advantages in fuel efficiency and cost, which is why many engineers are keeping it on their radars.
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PSA Peugeot Citroen has filed for 80 patents on its “Hybrid Air” system, which combines hydraulic power, compressed air energy storage, and a gasoline-burning engine. The company says the vehicle will get 45 percent fuel savings in urban driving and 35 percent overall. (Source: PSA Peugeot Citroen)
One very big advantage of the hydraulic hybrid is that the technology is quite mature, and lots of folks already know how to make all of the pieces. So it would mostly be a matter of making the pieces to car assembly standards, which should not be any problem at all.And those high pressure accumulators are very safe, a damaged high pressure hose is indeed messy but safe at fairly close distances. And they don't explode, they leak rapidly if they are severely damaged. And unlike batteries they can be bled down to zero stored energy without doing any damage at all. And a typical hydraulic drive system is much less likely to injure the ignorant person attempting to work on it. Make a big mess, yes, but no big shocks or burns.
As other readers have pointed out, this technology has been around a while, mrdon. Ford's Tonka truck (the last photo in the slide deck) was introduced in 2002. I know there were others before that, too.
One of the fixtures I design gets launched by compressed air. It requires 1 liter of helium @ ~ 800 psi to send a 1/2 lb bird down the tube at 500 ft per sec.
I'm just saying... 4000 psi.
I remember hearing that one gallon cup (typo) of gasoline has the same energy as one stick of dynamite (you just have to know how to get it all out at once to get the boom).
And I've seen the videos of lithium battery packs doing their extreme sudden energy release temper tantrums.
Stored energy generally is looking for a release... Controlled is good... Uncontrolled can be deadly.
For every new (to the consumer) storage/release regime there will be inherent danger to the neighborhood around the user. This hydraulic compressed gas idea could create a whole new set of concerns. Let me pick one...
Should these vehicles be banned from tunnels? Or is the potential low enough to say meh...?
But I do like it right off for things like the excavator... something where only the pros will be likely to be repairing and operating them.
Oh yes, I remember the headlines the Pinto made as well as the jokes. Again, a very good observation made regarding vehicle safety and its impact on public perception. No pun intended regarding "impact".
You just jogged my memory. I was at an antique car show this past weekend and there was one Pinto on dispay: Its personalized tag read: "KABOOM". For those that don't remember back in the '70s and '80s, Pinto's were known for blowing up when rear ended. Hopefully these 5000psi canisters won't leave a similar legacy ;)
Very interesting points regarding the environmentally friendly aspects of hydraulics to the electric hybrids. Yes, the though of sitting under a high pressure tank does provide a sense of uneasiness while driving such a vehicle.
Those are great questions. Most advances in the auto market focus on fuel economy. I guess that's because of the forthcoming fuel efficiency standards. But, any new car that includes easy and low cost maintenance and repair will explode on the market.
Globally, we're moving back to an urban-centric economy. People are sharing cars, and even bicycles. That's the future of the market. Low cost up-keep will trump the tiny gains we've made in fuel efficiency for consumers.
I like the idea of a mechanical hybrid better than an electric hybrid for environmental reasons. I remember a while back someone studied the lifetime energy cost of a Prius vs. an H3 (or an H2, I don't remember the fine details) and the Hummer won, mainly due to the production and EOL recycling cost of the Prius's exotic materials. I would assume (perhaps someone can correct me if I'm wrong) that a hydraulic system would be a win-win for the environment (assuming nothing exotic in this system).
On the other hand, being someone who keeps vehicles for decades, I tend to think about post-warrantee issues a lot (my family has a fleet that includes an '88, a '94, a '99, and a '10). That high pressure bottle makes me REALLY nervous (especially sitting right underneath the passenger compartment). After 10 years I would fear it's become a corroded mess (it's located in a prime spot to collect water/salt), that may start to approximate an explosive device.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.