SHORT CYLINDER BLOCK GROUP 7W4706 - Caterpillar

Caterpillar Engines Equipped With TurbochargersAlcohol mist injection systems are available from several sources for installation on diesel engines including Caterpillar-built Engines. According to their manufacturers, these systems increase both horsepower and engine efficiency. Among other advertised claims, they reportedly decrease inlet, cylinder and exhaust temperatures while providing cleaner combustion.
These systems inject alcohol mist directly into the engine's air inlet. The alcohol mist mixes with the air as it passes through the turbocharger and the inlet manifold. Once in the combustion chamber, it vaporizes and burns with the diesel fuel.
Tests of these systems at Caterpillar resulted only in short-term increases in engine efficiency. However, the increases were followed by severe decreases in efficiency.
Inspection and analysis of the engines and the test data have revealed two problems. First, the heat energy needed to vaporize the alcohol mist prior to combustion substantially reduced cylinder temperatures. As a result, the engine misfired. Second, because the mist is injected into the air inlet, the alcohol droplets severely eroded the turbocharger's compressor blades in a very short time. Continued use of the system would have necessitated the installation of a new turbocharger. The overall result was a severe decrease in engine efficiency.
For these reasons, Caterpillar recommends against the use of any alcohol mist injection system with any of its turbocharged engines.