> I guess I was specifically referring to car engines which, aside from the Wankel, are the same basic idea
Well, there have been a few commercially available cars driven by rotary engines (which are pistons being turned by a crankshaft, rather than turning a crankshaft) and cars driven by steam engines, but you're right that at the moment, only Otto-cylinder, Diesel, Atkinson, and Otto Wankel engines are on the market for cars, and all of these except for the Wankel are built around pistons turning a crankshaft.
But if you're talking about innovations on the level of more-efficient two-stroke engines, rather than totally new engine designs, I think you can find a lot of those that have made it to mass production in the last few decades. Atkinson-electric hybrids might be the biggest one, but there's electronic ignition control, gasoline direct injection, electronic fuel injection, coaxial springs to prevent valve dwell, continuous-jerk cams, hydraulic tappets, variable valve timing, etc.
That list certainly supports your contention that manufacturers are too conservative, though.
(I don't really know much about this stuff, so let me know if I'm making some kind of goofy mistake.)
It seems to me that in order to make manufacturers less conservative, we need to have more of them. Widespread CAD and simulation facilities and automated fabrication that lowers the cost of producing prototypes could make a big difference.
Comments
> I guess I was specifically referring to car engines which, aside from the Wankel, are the same basic idea
Well, there have been a few commercially available cars driven by rotary engines (which are pistons being turned by a crankshaft, rather than turning a crankshaft) and cars driven by steam engines, but you're right that at the moment, only Otto-cylinder, Diesel, Atkinson, and Otto Wankel engines are on the market for cars, and all of these except for the Wankel are built around pistons turning a crankshaft.
But if you're talking about innovations on the level of more-efficient two-stroke engines, rather than totally new engine designs, I think you can find a lot of those that have made it to mass production in the last few decades. Atkinson-electric hybrids might be the biggest one, but there's electronic ignition control, gasoline direct injection, electronic fuel injection, coaxial springs to prevent valve dwell, continuous-jerk cams, hydraulic tappets, variable valve timing, etc.
That list certainly supports your contention that manufacturers are too conservative, though.
(I don't really know much about this stuff, so let me know if I'm making some kind of goofy mistake.)
It seems to me that in order to make manufacturers less conservative, we need to have more of them. Widespread CAD and simulation facilities and automated fabrication that lowers the cost of producing prototypes could make a big difference.
BTW, the SyTech is another experimental non-crankshaft design: http://www.autospeed.com/cms/A_0948/article.html