Remarkable new fossil-fuel engine design is 5 times more efficient and reduces emissions 90%

The best are around 60% IIRC.

 

I doubt very much that he's denying 'climate change' rather he's denying those who believe that humans are the cause. Seeing as. They only contribute .26% of all green house gases and the world has been on a cooling trend for the last decade or more.

 

Maybe it's a turbo-carnot engine.

The limiting efficiency is defined by the carnot cycle. When you analyze the carnot cycle you quickly see that the limit to efficiency is the difference or delta in temperature between the hot side and the cold side of an engine. The larger the delta, the higher the efficiency.

Combined cycle plants increase efficiency by extracting heat after the power generation stage, thus lowering the temperature of the cold side. In other words, less energy is pumped out of the exhaust pipe. This isn't a new idea. It was used extensively with double and triple expansion steam engines, where the exhaust of each stage was feed to the next stage where more heat was extracted to do work.

The problem is one of diminishing returns. The lower the heat delta, the harder it is to extract any useful amount of energy. The third expansion of steam on a triple expansion steam engine requires a HUGE cylinder and piston. It worked okay on ships, because they are big and can tolerate a lot of weight, but it's not so good with a compact car.

So getting back to theoretical efficiencies, no heat engine can achieve efficiencies above that of the theoretical carnot cycle engine, no matter how clever the design. As you approach that level of efficiency, all you can do is use hotter fuel, or a colder exhaust.

Tom

 

Could be true but might have a huge RPM and extremely low torque, requiring a flywheel.
This could be a great efficient gas driven generator or compressor.

I still think the best ICE out there will be Ford's direct injection. For a full size car or SUV, if the HSD could be Ford's DI V4 or V6, instead of IMA tech, could triple MPG on the big guzzlers w/o sacrificing torque.

Would be interesting to see the Ford Escape Hy with such a tech combo to test the system, instead of simply using IMA or Start/Stop.

(iow, instead of HSD's ICE being Atkinson, a V4 Direct Injection HSD)

 

Certainly. There are a lot of slick ideas, and more to come. Size, durability, and other factors are also important.

My explanation was directed toward physical limits. No design, no matter how clever, can overcome the limits of physics. Of course our current understanding of physics could be flawed, but it's not likely. This part of the physical world is well understood.

Before the carnot cycle was understood, engineers spent a lot of time working on steam engine efficiency. At first they made big gains, but the return for their efforts became smaller and smaller. Everyone assumed that all they needed was a better design. Then Carnot came along and demonstrated that the current designs were butting up against the theoretical limits. There was no need to keep beating that horse.

Tom

 

Can't even be bothered to click the links but I assume on the same page talk of the 200 mpg carburetor.

Get back to us when this is in a production vehicle. Until then it's vapor-ware.

I once conceived of a gas powered vehicle that had no loss of torque at speed and infinite acceleration. Then I thought about it more and realized oops that won't work. (this occurred in the period of maybe 30 minutes). There thousands of breakthroughs for cars, from better engines to air powered vehicles. But concept is easy, putting it in practice is not. You know how only 1/10 of small businesses survive? I bet the numbers aren't that favorable for "ground-breaking" advances in automotive engineering.

 

I was wondering if Mojo had ever heard of Carnot. Mojo ?

A quick google suggests that exhaust heat is about double that of ambient air on the kelvin scale, implying a theoretical maximum efficiency of 50%. Sound ballpark Qbee ?

 

I had long understood the theoretical limit to be Eff = 1 - (Tcold)/(Thot).

Tcold is mostly fixed at no lower than 300K. (Thot) is often limited by materials, but with turbine engines running above 1000K, it seems that we should have theoretical room to go well above 40-50%.

 

That sounds about right, although I haven't bothered to turn on the calculator.

Tom

 

I should clarify I was talking about cars. As Fuzzy points out industrial machines can run hotter.

 

Why can't you brainiac engineer-types just do a nice hydrogen fuel vehicle and forget all the fossil engine burners? Is hydrogen explosive? Yes, but so is a tank of gasoline. I'd think it really cool if we could use water to fill-up the 'ole tank. I just like the idea of hydrogen.

 

With a Brayton cycle (gas turbine) followed by a Rankine cycle (steam turbine) some modern large complex power generating stations hit 60% operating under design conditions. That does require a cold heat sink of 300K or less.

The concept is old. We played around with concepts in thermodynamics class over 40 years ago that would run at around 60% if they had been buildable. It took higher fuel prices, materials improvements, better control systems and a lot of development dollars to make the combined concept work as well as it does. The resulting powerplants are big, like building size big, complex and expensive and only hit their target efficiencies under steady state conditions.

I find it hard to believe that the hypster we are discussing has a simple device that reaches 60% thermal effieciency. He makes enough patently bogus claims that anything he says is suspect.

He claims his system will reduce power train weight bu 1000 lb but he is only developing a 30 hp engine and the total weight of a 30 hp power train including engine, transmission etc is well under 1000 lb. An entire 36HP VW Beetle power train was around 400 lb and that's pre-WWII technology. It would be difficult to reduce that bu 1000 lb

He also claimed a 90% reduction in CO2 emissions. CO2 emissions are roughly proportional to amount of fuel burned. Even at his bogus 5x fuel efficiency claim, it would only be an 80% reduction.

In his 2 year old video he claimed he would have a prototype running in 2 years. His video is 2 years old, where' the prototype?

I hope he is using something more concrete than the bogus claims he is tossing out to the gullible to extract our tax-dollars from ARPA.

 

I prefer pixie dust and butterfly farts, but if you develop an inexpensive source of hydrogen the problems of handling it will be solved.

 

The brainiacs have been working on this for probably 20 years. GM might not have gone bankrupt if they didn't spend so much on R&D for this (they planned on spending $1 billion in the late 90's). So far, engineers have made cars like the Honda FCX that are perfectly functional, but with limited range and the fuel cell alone costs over $100K (understandably, they're not really talking too much about this, so the actual prices are hard to find). Also, you have the problem of producing hydrogen.

Most commercially available hydrogen today comes from natural gas (electrolysis of water is not that efficient). Better to use a normal ICE runing directly on natural gas - cheaper and fewer conversion points to lose efficiency. (I like natural gas engines myself - they've been done for decades around the world, so the technology is there, on par with gas and diesel engines, and the U.S. has enough natural gas to supply a good percentage of our transportation needs without having to import it from overseas).

 

Unlike Skoorbmax, I did follow the link. Definitely looks promising, but obviously early in development, I hope he does get some funding to follow this up. If it works out, it's a potential game changer, if not, we probably lost considerably less on it than a day with the military in Iraq.

Couple points: designed to produce electricity, not turn a driveshaft directly, so it must be low-torque. He mentions batteries to be used for high-demand situations (accelerating, passing). Also, in the video he says the 5x/3.5x improvement is in (theoretical?) fuel economy, not in engine efficiency. That makes a difference and makes it more believable.
If it works that'd be great, but it still has to be proven in the real world - will it start in below-zero temperatures, can it be used for 100K miles without major repairs, does it use any expensive materials that will drive up the price exorbitantly (like that platinum in fuel cells)?

 

Fuel cell technology is still insanely expensive. Fuel cell cars are thus tens of thousands of dollars more than a comparable ICE car.

I'm not even sure hydrogen's cost is that bad compared to gas. I think it's more lack of infrastructure and more importantly the cost of the vehicles.

One of GM's main fuel cell research centers is in this area and I've seen an equinox (?) fuel cell vehicle a couple of times.

EVs make sense because the infrastructure is already here. In some ways more ubiquitous than gas vehicles, but the obvious draw back of hours to charge them up.

It might be, my point is there are vast huge numbers of technologies that are years away from production, and in every area of human research from cars to medicine. And production is the one and only proving ground. Can it be made to work properly at a reasonable cost. Until then everything is just a research paper.

 

Yeah, that part seemed a bit suspect. He said no transmission, radiator, etc would be required, but then didn't really mention you would need to add a generator, electric motor and batteries.

The video dates from Oct 2009, which is 1.5 years, and I heard him say he wanted something in 3 years. (There was one point earlier he gave a timeline, but I couldn't understand exactly what he said, but I think that was for a production-release car). I didn't notice the date before, I wonder why the story was brought up at this time, I don't see that anything changed.

It sounds like the head of ARPA-E is pretty knowledgeable, hands-on guy who actually visits the sites of the grantees, and looks at what they're doing and asks questions, so I don't think they'll get too taken in by this. Did you follow the link to the ARPA-E website?