This paper is to analyze and study the cause of fire examples produced because of short phenomenon by electric connecting damage and contacting engine overheating with combustible materials in engine room of vehicle. In the first example, it knew the fact that the fire produced by contacting with body of vehicle because of loosed of bracket bolt for wire fixing that installed on the transmission case the battery power cable supply the power from battery of engine room to starting motor. In the second example, it certified the fire by short phenomenon because of insulation tape melting wound wiring lined from battery to starting motor. In the third example, it sought for fire's cause that melting phenomenon the wire coating by overheated engine as the wire disconnected with connector by the vibration. Therefore, the fire of system including engine electric made in the danger the people in the car by failure of engine and other system. And than, the car's driver must manage and examine a vehicle conscientiously.

In the case of 4 wheel drive (4-WD) type car, power switching occurs to 4-WD by operating lever or switch that operates power switching device attached in transfer case which can operate motor by electric signal. So if the RPM of motor is high, power switching will not exactly occur and can cause damage to gear in transfer case according to circumstances. So in this study, we applied 2 level of planet gear type motor spindle of motor drive part of a power train. And conducted decelerating to increase torque to switch power safe and accurately. Also, we researched efficiency of gear by designing reduction gear ratio and gear type and by calculating contact stress and bending strength. Based on researched content, we made drive head of power switching device and a reduction module which uses type that uses motor spindle as sun gear and ring gear as cover. 기호설명 R = Reduction gear ratio Zr = No. of ring gear teeth Zs = No. of sun gear teeth ρ= Radius of curvature m = Module D = Pitch diameter σ c = Compressive stress Fn = Vertical load Ft = Radius of curvature E = Young's module M = Moment1. 서론 자동차는 엔진의 동력을 클러치, 변속기, 차동 장치, 액슬축과 같은 동력전달장치를 이용하여 바 퀴를 구동시킨다. 1 또한 구동방식에 따라 전륜구동 방식(front wheel drive)과 후륜구동방식(rear wheel drive) 그리고 사륜구동방식(four wheel drive)으로 나 뉜다. 2,3 현재 국내에서 제작되는 승용차의 80%이 상은 앞바퀴를 이용한 전륜구동방식을 채택하고 있다. 하지만 레저인구의 증가로 인하여 SUV나 RV차량의 수요가 증가함에 따라 4바퀴를 모두 구 동하는 사륜구동방식의 차량이 꾸준히 증가하고

The purpose of this paper is to study for the emission gas control of passenger car. The first example, the PCSV never open when operating condition, but it opened by causing malfunction because of trouble. As a result, the purge gas entered into surge tank, a mount of fuel was displayed with excessive supply on tester. Therefore, it certified the bad-condition of the engine when idling by decreasing of fuel injection quantity from engine ECU. The second example, the hose activating a EGR valve didn't supply the vacuum pressure because of assembling the other part. Thus, it knew the bad-condition of engine that the EGR valve would not work normally by leaking with the other port. The third example, as the rear oxygen sensor of two sensor were fault-installing by changing the sensor of other a car it could not detect of oxygen quantity. Finally, it found the phenomenon of abruptly decreasing vehicle speed when braking a car. Therefore , the system including with emission control has to drastically manage by maximizing condition to role decreasing the emission gas.

-This paper is to analyze and study the fire examples in respect of intake and exhaust, alternator tuning and inflow of inflammables on exhaust part in a car. In the first example, the driver diverted the intake and exhaust system for tuning of a car. Stopping a car to rest for moment, the flammable styrofoam scrap go into exhaust pipe that installed with exhaust manifold newly. It certified the fact that catched fire gradually, furthermore enlarged the fire by leaking fuel. In the second example, the driver enlarged the generator performance to divert the audio system in side room., it knew the fact that the electric wiring connected with generator gave the cause of outbreak a fire by overheating. In the third example, the serviceman replaced the engine oil using funnel-shaped, he put the a bottle of plastic pat onto engine cover carelessly. Consequentially, it found the fire occurrence in the engine room. Therefore, the driver never divert the intake and exhaust and generator construction of a car abnormally. Also, repairing and inspecting a car, the serviceman have a care to not occur the fire by inflammables.

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