MANUFACTURE OF CONNECTING ROD OF A SINGLE-CYLINDER, FOUR-STROKE, 8 HORSE-POWER (8 HP) DIESEL ENGINE BY REVERSE ENGINEERING TECHNIQUE

Abstract

In order to boost local production of major internal combustion (IC) engine components in Nigeria, this project work was aimed at producing connecting rod of a single-cylinder, four-stroke, 8hp diesel engine by reverse engineering method using lost wax casting and machining processes. The connecting rod is required to transmit the compressive and tensile forces from the piston, and rotate at both ends. The manufactured connecting rod was interchanged with the original rod in the generator. Performance tests were carried out on the manufactured connecting rod. The engine with the original connecting rod was used as the control engine to measure the performance of the engine with the manufactured connecting rod. The engine temperatures were taken for the control engine and the engine with the manufactured connecting rod under two experimental conditions of no-load and 3hp load. The temperatures were taken for a period of 1 hr. at an interval of 5mins. A graph of engine temperature against time was plotted for both engines. For the control engine, the results showed that there was a steady rise in temperature under the no-load condition and under a load of 3 hp. for the first 15mins of running the engine. After 20mins of running the control engine, the temperature dipped with 2oC under the no-load condition and 1oC under a load of 3hp. The engine temperature began to rise again after 25mins under both experimental conditions. However, both experimental conditions recorded the highest temperature difference at 45mins, with the engine under no-load condition recording an increase of 47oC and the engine under a load of 3hp recording a temperature rise of 49oC within the same space of time. After 1 hour of running the control engine, the engine under a load of 3hp recorded the highest temperature of 200oC while the engine under no-load condition recorded a temperature of 190oC. For the engine with manufactured connecting rod, the results showed similar trend in temperature rise. However, the engine under no-load condition recoded its lowest temperature rise of 2oC at 20mins. Again, under the no-load condition, there was 0oC temperature rise between 25mins and 30mins as the temperature was stable at 69oC. The engine under load of 3hp recorded the highest temperature of 201oC after I hour while the engine under no-load condition recorded a temperature of 19oC. The results also showed that the engine speed reduced with 3.06% under 3hp load condition as against the value of 250 rpm when the control engine was under no-load condition. The same decrease in value for the engine with the manufactured connecting rod was recorded. The speed of the engine reduced with 0.88% under 3hp load condition from the 793 rpm recorded under no-load condition. However, the reduction in speed was more for control engine than for engine with the manufactured connecting rod.

KEYWORDS: Connecting rod; Internal Combustion; Engine; Temperature; Cast Iron.