ABSTRACT Exhaust gas – Intake air Heat Exchange in Diesel Engine Eng. Monaf Hodhod , Zyad Al-Shehri and Mohammed Ghazwani College of Engineering ABSTRACT MATERIALS / METHODS CONCLUSIONS In case 1, when the intake air temperature is less than 20 C, the air flows from the Cooling room pass the changeover Valve into the heat exchanger which has already hot exhaust gas flow comes from the engine. Then, the cold air is preheated before getting in the engine. This case continues until the intake air Temperature reaches to 25 C. At this moment thermostat sends a signal to the changeover to close the air way to HE and open the other way. In case 2, when the intake air temperature increases to more than 25 C, the air flows room pass the changeover valve directly into the engine, this process continues until the air temperature reach to 20 C . At this moment the thermostat send a signal to the changeover valve to close the direct way and open the way to HE. And so on. The difference of Fuel Consumption for ambient Temperature (T=4~7C & T=20 to 25C) We observe that there is an improvement in Fuel Consumption of the engine as follows: At 1200 rpm with no load the Fuel Consumption decrease form 0.6318 kg/h to 0.63 kg/h a 0.2% less Fuel used. At 1800 rpm with no load the Fuel Consumption decrease form 0.9936 kg/h to = 0.959 kg/h a 3.6% less Fuel used. At 1200 rpm with 30% load the Fuel Consumption decrease form 0.729 kg/h to 0.673 kg/h a 8.3% less Fuel used. At 1800 rpm with 30% load the Fuel Consumption decreased form 1.6704 kg/h to 1.539 kg/h a 8.5% less Fuel used. At 1200 rpm with 60% load the Fuel Consumption decreased form 1.8972 kg/h to 1.769 kg/h a 7.5% less Fuel used. At 1800 rpm with 60% load the Fuel Consumption decreased form 4.8978 kg/h to 3.090 kg/h a 36.37% less Fuel used. Based on the results collected. We got an overall increasing in efficiency notable reduction of fuel consumption with and without load. But there was an increase in performance in no load situation but a little decreasing in performance with load . In this project we designed a heat exchanger and installed it at the end of exhaust system of diesel engine to preheat the intake air while the ambient temperature is very low specially in winter days . For this issue we designed also a small cooling room to get low temperature air as in winter (less than 5 C). Also we added a simple control system to keep the intake air temperature in certain range between 20 C– 25 C . This range is suitable for operating diesel engine. The main objectives of this Heat Exchanger to get stable operation with good efficiency as well as reducing the fuel consumption. RESULTS REFERENCES [1] Retrieved from Mechanical lab experiment, internal combustion engine (diesel engine). [2] Retrieved gunt hamburg diesel engine program Ct 400.02 [3] Foundation of heat transfer Frankp.incropera Davidp.dewitt theore l.bergman adriennes.lavine sixth edition [4] Mechanical lab experiment ,Cross Heat Flow Exchanger [5] thermodynamics an engineering approach sixth edition, publication OBJECTIVES Workshop on: Green Technologies & Energy Efficiency April 26, 2017