And that’s what his company, LiquidPiston, has apparently done with its 40bhp LiquidPiston X2 rotary engine. With a name like that, I was really hoping that the engine really used liquid pistons; it doesn’t. Even so, it is very noteworthy that it is able to drastically improve on the thermal efficiency compared to conventional ICEs. In fact, Shkolnik claims his X2 rotary engine has a thermodynamic efficiency of 75 percent. By contrast, an ICE only coverts 30 percent of its heat into work. That’s huge.

Even though LiquidPiston has combined several innovations from more conventional designs, like the Otto Cycle and the Wankel engine, it is actually simpler and more compact. It only has three moving parts–one of the reasons why they went with rotary over a regular piston engine–and 13 major components. The net result is the X2 is only 1/10th the size of a comparable diesel engine. The design, by using constant volume combustion and overexpansion, is better able to burn more of its fuel too; regular ICEs have a lot of unburned fuel spitting out their tailpipes.

As with all of these kinds of innovations, I’m skeptical, especially when it comes to scaling this LiquidPiston X2 design to produce way more than the 40hp it currently generates, but I wish Shkolnik and LiquidPiston all the best. They really need to get this in the hands of a major automaker; otherwise, it’s just another forgotten design. It helps that the X2 can burn a variety of fuels, making it more flexible moving forward.

[Source]

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Finding fuel-efficient cars in Europe is nothing out of the ordinary. Many of them are very efficient diesels, for instance, but the diesel market in North America for smaller vehicles isn’t as established. However, the Jetta TDI will soon have some competition in the form of a diesel-powered Chevy Cruze.

This has been officially confirmed by GM CEO Dan Akerson. The car itself isn’t huge news, but the diesel Cruze will be the first diesel car out of Detroit since the 1980s. That’s a very long time. If you’re willing to accept something a little bigger, the last passenger vehicle diesel was a 2006 Jeep Liberty CRD.

Part of the concern for passenger diesels in the past was noise, but Akerson is saying that these new diesels are quiet and that they are able to make it in the low to mid-40s for fuel economy. By comparison, the diesel Jetta with an automatic transmission gets about 30mpg in the city and 42 on the highway. The gas-powered Cruze Eco gets 39mpg on the highway. It’s an issue of the chicken and the egg, but finding diesel pumps can cause some trouble for folks. Though as Detroit puts out more of these types of cars, that’ll likely change. Expect the diesel Cruze to hit American streets in 2013.

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