Variable Compression Ratio Engines

The solution to extended Internal Combustion Engine longevity, or a niche and belated breakthrough?

The increased industry requirement for fuel consumption improvement and reduction of pollutant emissions is pushing the industry to adopt new technologies for gasoline engines as they compete for longevity in the face of electrification alternatives. The recent trend for engine downsizing and forced induction have already delivered improved results. However, the material technology improvement required to handle higher specific power and peak temperatures is heightening the challenge to develop reliable power units, regardless of fuel type. For example, new diesel engines now require heavier and stiffer bearing components, while new gasoline engines specifically running on alternative fuels require knock mitigation solutions to operate at higher average peak pressures at high speeds. With the introduction of variation in compression ratio, the fuel consumption in the developed gasoline engines can be reduced with optimum compression ratio at corresponding low and high engine loads, without significant increase in peak firing pressure load, thus lessening the requirement for strengthening measures, therefore increasing compactness and flexibility in engine design. Variable Compression Ratio (VCR) engines offer a solution to increase the longevity of internal combustion as the choice of powertrain energy source.