Can CGI be considered for future in-line engines that are smaller than 1.5 litres?


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Engine designers will use CGI to reduce weight and/or to increase specific performance (kW/litre). As the engine size becomes smaller, the ability to reduce absolute weight (kg rather than percent) becomes smaller. Therefore, the driver for CGI in small engines will not be based on weight reduction through redesign.

The opportunity for CGI in small displacement engines is to use the strength of the material to increase the operating loads, and thus the specific performance (kW/litre). A fully loaded 1.2 litre CGI engine could potentially provide the performance of a conventional 1.4 or 1.6 litre engine. AVL, the engine design consultancy based in Austria, has shown that a turbocharged 1.3 litre CGI diesel engine operating at a peak firing pressure of 180 bar can provide the same performance level as a current production 1.8 litre grey iron engine. This is the real opportunity for size and weight reduction for small in-line CGI engines ... a 1.2 litre CGI engine will only be a few kilograms lighter than a 1.2 litre grey iron engine, but it will be much smaller and lighter than the 1.4 or 1.6 litre engine that it replaces. Another advantage is that smaller engines have less frictional losses than large engines, so the 1.2 litre CGI engine will also be more efficient than the 1.4 or 1.5 litre grey iron or aluminium alternative.

Engines with displacement of less than 1.5 litres are a definite part of the "In-Line Wave" in the SinterCast "Five Wave" scenario. In addition to size reduction, CGI may also find applications in allowing a grey iron engine design that is near the end of its life cycle to be boosted to become market competitive with newer engines entering the market, thus prolonging the life cycle of the engine family. We can also hope to see high-efficiency single-cylinder CGI diesel engines used in future hybrid (electric-plus-internal combustion) powertrain systems.