Another ICE design: the OPOC engine

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Try this one:

Sorry --- this is a duplicate.

 

Interesting. Thanks Okie & LeadingEdge. Sounds like they're claiming a slight improvement in FE but mostly a big improvement in weight to power ratio. But it still burns fossil fuel.

 

What's it cost to exploit deep geothermal energy?

 

Does heat transfer through the rock down there any faster than the rock near the surface? I don't think so.

Therefore the volume nearest the heat collector will experience some temporary depletion, similar to heat pump issues nearer the surface, unless they $eriou$ly overde$ign it.

 

I looked at a few sources of information that I found with Google before the OP fixed the link. None of them had specifics on fuel consumption. Since these engines have been in operation for a few years, and I know that if it's DARPA project that there is tons of actual data, I can only conclude that the FE is unremarkable.

OTOH, if FE is a bit better than normal engines, emissions are as low or better and it's lighter more compact power source, then there is some promise, but I also doubt that.

With the lack of solid data being made available, though, I think that as a car engine it's just another nocturnal emission from a company fishing for investors money.

 

These have actually been around before. Using modern engine controls may be new.
Opposed-piston engine - Wikipedia, the free encyclopedia
Don't know how clean you can get it with it being a two-stroke, but lighter weight and smaller size will improve PHEVs. At least more so to them than a standard car.

 

Hi xs650,

In the video the guy said 230 g/kwh, or about 40% thermally efficient in a Diesel variant. Not sure if that was Turbo Diesel or not, but they did show a Turbo Diesel engine version. That is unremarkable for a Turbo Diesel, but OK. If I remember correctly, the Gen III Prius engine is 235 g/kwh , or 38 % efficient.

The issues with these new designs is specific friction, and heat loss. Allot of the rotary designs seem real good, until one realizes that the heat is going to leak out of the things because of the large surface area/ compressed volume ratio. Which is probably the problem with the Mazda RX cars. Until materials are developed that are producable, high heat, low friction and good thermal insulators, the rotary concepts wont be that good. And with those materials, one might improve the piston beyond the improved rotary with this same materials.

This design probably has the specific friction issue. It has in effect extra crank drag due to the outboard piston pivot pin. But, its not a total game-changer, as the thing can be made so lightweight, in the total car system, the car might actually get better fuel economy than a traditional engine of the same power.

But at the same time, this engine does not match up well with the REEV hybrid concept, because the batteries are arleady so heavy, that the 100 - 200 pounds saved in the engine is not a great fraction, and the car structure needs to be nearly as heavy anyway. I am thinking a free-opposed pistion electro-magnetic engine makes more sense for a series hybrid. That way, the engine friction losses are pretty small.

It might be good for Prius style hybrid, if an Atknisation can be devised. Because their the batteries are only 80 pounds, and an engine that is half the wieght is a big deal. I am thinking a free-opposed pistion electro-magnetic engine makes more sense for a serie

 

Thanks for the information. Definitely other engine technology can get there. This may be lighter and cheaper than those other engines. I doubt it has lower pollution.

This may make it a good fit for a phev. I doubt it really makes much sense in a non plug in hv or standard car. Better fuel economy in those vehicles seem to be following the low friction DI route. This engine does have an advantage of flex fuel.

My personal favorite for a phev engine is a turbine. It is light and flex fuel and potentially very highly efficient, and the batteries fix most of the problems of constant speed and accelerator lag. Jaguar has a prototype turbine phev. GM had a serial turbine generator on an ev1 version but rejected that with the rest of the car.

 

Gen 2 Prius was 230 g/kWh. Gen 3 is 220 g/kWh. What's also important is not just the peak efficiency but the range of speed and load of that efficiency peak - on the Prius engines, both are pretty broad - and how quickly it declines away from the peak.

Gen 2:



Gen 3:



Images from Brake Specific Fuel Consumption (BSFC) Maps - EcoModder, where you can compare other engines that they've managed to find consumption maps for. For example, here's the VW 2.0L turbo-diesel used in the Jetta, with a peak of 196 g/kWh:



I imagine that the Prius engines actually have an even better peak efficiency point, but Toyota have chosen to only plot the innermost contour because holding the engine at the peak efficiency point is going to be extremely hard.

The 'basic operating line' on the Toyota graphs is also worth explaining. Because the car effectively has a continuously-variable transmission, the hybrid vehicle computer can pick whatever combination of load and engine speed makes up the necessary power for the current road demand - in practice this means it can generally run the engine at high load and minimum revs (top-left corner of the chart). It therefore sticks as close as possible to the line marked on the chart. You can see that the Gen 3, above a certain point, is optimised for highest power output rather than most efficient as the Gen 2 was, joining the outermost wide-open-throttle line.

 

Thanks for the maps, those are hard to find.

If you look at the map in 3 dimensions, the slope as you go up the BSFC contours on the Prius is shallow compared to the TDI and the TDI peak is only 4 g/kW-hr better than it's best contour of 200. Since the Prius only has about 1/2 the slope, I suspect it's peak is only about 2 g/kW-hr better that it's best contour.