Intake, compression, power, exhaust; those are the four basic commandments of the modern internal combustion engine. Automakers were content with keeping the traditional recipe as long as customers were happy, but after all there is an atmosphere that we rely upon for breath and as the saying goes, don't piss in the well unless you like yellow water. To help clean up the act, automakers are hard at work making the ICE more efficient. Here are the most promising advances on that battlefront that we can expect to see in the near future.
Most fuel saving technologies center around eliminating the compromise between efficiency and power by delivering both when needed. Nowhere is this embodied in a more straightforward manner than in cylinder deactivation. Now, the process has been refined. Advanced cylinder deactivation makes it so that the system can vary how many cylinders and which of them are shut off at any given time, allowing for more flexible manipulation. If combined with staggered displacement cylinders, the power output of an engine could be tailored with surgical precision, essentially packaging a small-displacement fuel sipper meant for civilized driving into the same unit as a larger engine that has the power when you need it.
With the recent advances in electric vehicles, hydrogen technology appears to be vanishing into the shadows, but automakers haven't pulled the plug just yet. In fact, California residents are now privy to three different cars all powered by the first element on the periodic table. Recent advancements in hydrogen storage methods such as conformable tanks may place hydrogen's downsides into the history books. Mercedes has even announced a plug-in hydrogen version of its GLC SUV, essentially an electric vehicle with a hydrogen fuel cell in place of a range-extending gas engine, slated for release in 2017. If it becomes practical enough to catch on, the zero-emissions car could soon roam the streets exchanging soot for H2O.
For its entire existence the internal combustion engine has used the motion generated at the crankshaft to power the camshaft, which in turn keeps the crankshaft moving. The problem is that the camshaft robs the engine of power and in turn, hurts fuel economy. To solve this, some automakers like Koenigsegg are toying with the idea of cam-less engines. In place of the mechanical system, a cam-less engine has a series of electronic actuators to control the valves, lessening the engine's load and allowing for highly specific computer controlled valve action. In the past, these systems used too much electricity to be practical, but as automakers switch to higher voltage systems, the cam-less engine is becoming viable.
The camshaft isn't the only belt-driven engine component that could be replaced by electricity: the supercharger may soon go the same route. Turbochargers are favored by automakers chasing efficiency because they make extra power using exhaust gas instead of robbing it from the engine, but electric compressors could help to change all that. Its main advantage over the turbocharger is that the supercharger provides lag-free power delivery, helping motorists feel as though a smaller displacement engine really does have the power of a larger engine. Volvo plans to utilize electronic superchargers to spool up its new twin-turbocharged four-cylinder engines and cut lag, and we can expect other automakers to follow suit.
Engines with high compression ratios make more horsepower per liter but tend to be inefficient. To help smaller engines take advantage of the power boost without the penalty of increased fuel use, the variable compression ratio engine is being considered. Earlier units worked by using mechanical components to alter the piston's placement, but this system was too complicated and prone to expensive breakdowns. Now, engines can artificially alter compression by playing with the valves to allow more air inside the cylinder and to close sooner to keep it trapped, raising the pressure inside and mimicking an engine with a higher compression ratio. This is an area where the cam-less engine would help by providing a wider range of valve manipulation.
