Gallery: The Rebirth of the Internal Combustion Engine

Too bad the Larsen RADAX engine isn't here. There's a couple similar models though.

The only one with merit is the shock wave engine. All the others trade off far greater complexity, weight and cost for fuel efficiency. Two of the designs depend on problem prone sleeve valves, old technology long since rejected.

Aside from the Michigan State engine (give it a name, please!!! M-Shock, perhaps?), all of these designs suffer the same problem that most engines do: they use power-robbing, problematic reciprocating parts. The Michigan State engine starts off with what should be the most important feature of any engine or motor: it rotates on its own center of gravity, maintaining its own inertia.

The illustration of the Pinnacle engine does not show one or more key features: it will, at least, require one or more long rods to connect and synchronize the two cylinder banks of the engine. That rod will work against the efficiency of the engine, adding weight, complexity and vulnerabilities. Yes, it eliminates a static cylinder head, but replaces it with an extra rotating mass: it has two crankshafts, rather than one. That extra crankshaft is a double penalty: not only does it add more weight to the engine, but any mass that must spin up during acceleration robs you of even more energy than mass that is stationary relative to the rest of the engine (and the vehicle.)

The EcoMotors engine has similar problems: the long rods on the sides not only add masses that have complex semi- reciprocating masses that need to be spun up upon acceleration, but the length of the rods themselves are problematical. The longer and skinnier the rod, the more vulnerable it is to harmonic fatigue and failure. You have to compromise-- either a heavier, less efficient rod to attain decent RPMs, or a lighter rod that limits your top-end and power.

The Michigan State (M- Shock?) engine has promise, but the article does not give enough data to be very reassuring yet. It shares some characteristics with turbines, which may tell us something about what we may expect from it. Without valves closing rapidly hundreds of times a minute, the M-Shock may be a very quiet engine, requiring little or no sound muffling. It appears to have only one major moving part, which is turning on its own center of gravity, and that one part appears to be very light in mass, so that on spin-up, it will accelerate rapidly.

It is such a radical design that it would be foolish to try to guess its efficiency; despite simplicity and rotating on their own center of gravity, turbines are unfortunately rather inefficient. The M-Shock may look like a turbine, but operates with different principles and hopefully may be far more efficient.

A major factor to be resolved is its emissions-- can it burn cleanly? Clean enough that it will need no emissions gear whatsoever, perhaps? Or maybe it's very efficient, but very dirty, so that by the time you clean it up, it's only as fuel efficient as, say, a Wankel engine, which is what made the otherwise lovable Mazda RX cars such gas-guzzlers. I do hope it's a clean, efficient burner.

Regardless of how good the engine is, it's still an ENGINE... it still uses fuel... and will still leave us somewhat dependent on foreign oil, still have a carbon footprint, which is why I'm such a fan of electric vehicles. This engine may at least help get us by until EVs can hit their stride.

Thanks, PopSci.

All these concepts require some sort of catalytic converter to clean up the exhaust.One engine concept that could do away with the need for a catalytic converter is the Cyclone external combustion engine.It burns anything flammable,and combustion is complete,so no exhaust cleanup is required.It's efficiency is similar to a diesel.Google: cyclone power technologies waste heat engine

Impressive, now if they could just break out the rest of the patents the oil and gas compamnies stole from the original inventers and quit poking around. just quit giving executives bonuses until there are several new breeds of autos that all get 75 to 150 miles per gallon of gas

Roy_H and billdale, the shockwave engine is unique in the simplicity of the basic operation. My first thoughts deal with throttling and torque output. Since combustion timing is fixed by port locations, it doesn't seem to be a variable RPM motor design. That would also mean fixed torque output. Engine simplicity is no guarantee that everything past the output shaft will also be simpler.
The lead-in did mention a possible use in generating electricity so a Volt-like drive system could be more efficient.

There's always time to do it better NOW.

Funding for internal combustion engine development dried up decades ago. "It's all been done" was the mantra. This proves there's always room for improvement, even when one generation arrogantly believes they've reached the pinnacle.

"...dried up decades ago"?

Where is that true? Certainly not in todays world.

The I/C engine is nowhere close to being tossed on the proverbial trashpile. Each model year brings improvments in engine efficiency and durability. Funding for I/C engine development is seen everytime you watch NASCAR, Formula 1, IRL - any motorsport and you will see proof that I/C engine development has not 'dried up'.

Two words: Laser Injection.
Now if they could work in magnets into the engine design so that they could advertise magnetic fields, it would possibly be the most sellable engine in the world. I have no idea how it would work.

It looks like the internal combustion engine is in earnest hands. We will see how many of them become practical to put in vehicles though. Just because an engine is extremely efficient doesn't mean that it has enough torque to get a human vehicle moving quickly or offset its own weight or that it would be any fun to drive. I'm sorry, but I won't drive an extremely efficient vehicle if it sounds absurd. That would drive me crazy every time I drove it.