Abstract : Stringent emission regulations in the world are being proposed with growing concern on NOx, PM and CO2 emissions. Diesel LDV are being applied with LP-EGR and HP-EGR in order to respond to these regulation. LP-EGR rate is greater than HP-EGR rate and low temperature, reduction of NOx by low temperature combustion and high EGR rate can be effective. Exhaust gas emissions contain NOx and SOF elements, these elements condense dew point condition in intercooler by difference between exhaust gas temperature and ambient temperature, condensation water contains acid components. Condensation water contains pH 3~4 depend on the condition of the engine rpm and torque. Experiment results, Al3005 with Ti, Cr had more resistant of corrosion than other Al material and relatively less weight reduction