# Reliability Optimization Design of Diesel Engine System Based on the GO Method
## 2 Diesel Engine Reliability Modeling and Distribution Based on the GO Method  
### Diesel Engine System Analysis  
The diesel engine system is composed of a crank connecting the rod mechanism, valve mechanism, transmission mechanism, fuel supply system, inlet, exhaust, and turbocharge system, lubrication system, cooling system, starting system, and electronic control system. The electronic control system provides the electronic control signal for the starting system, which feeds back the state of the engine in real-time and adjusts the amount of fuel through various sensors. The starting system adopts two starting modes--dominated by high-pressure air starting and supplemented by electric starting--to satisfy the reliable and fast starting of diesel engines in various environments. The crank connecting rod mechanism converts the reciprocating motion of the piston into the rotating motion of the crankshaft through rod connection, driving the transmission mechanism to operate. Regarding the  
Figure 1: Process of diesel reliability optimization design based on the GO method.  
transmission mechanism, the valve mechanism, cooling system, lubrication system, fuel supply system, and generator are driven through the gearing transmission of the crankshaft and each transmission gear. The valve mechanism directly achieves timely opening and closing of the valve through the rotating motion of the double-top camshaft to ensure fresh air into the cylinder and exhaust gas out of the cylinder. The fuel in the fuel tank is filtered by a strainer and pressed into the fuel filter by the fuel pump. The filtered fuel enters the injection pump. The injection pump produces high-pressure fuel, which is injected into the cylinder by an injection pump. The return fuel of the injection pump passes through the fuel radiator and returns to the fuel pump. The return fuel of the injector flows into the expansion tank through the float valve. The cooling system is a single-pump and single-cycle cooling system. The water pump pumps the water out of the tank and passes it through a fuel heat exchanger to cool fuel. Then, the water enters a parallel water channel and intercooler to cool high-temperature air. Finally, the water enters the radiator to be cooled through the return pipe and then flows back to the water pump, completing the whole closed cycle. The engine oil in the sump is pressed into the oil heat exchanger through an oil pump. The cooled oil is divided into two ways: (1) entering into the centrifugal filter and the clean oil returning to the sump after filtering and (2) entering into the main oil channel through the oil filter and then going through various pipelines to lubricate each lubricating point and cooling point of the diesel engine, finally returning back to the sump. The air filtered by the air filter is pressed into the inlet manifold by the compressor, and the air is cleaned and transported to the cylinder under the action of the valve mechanism, contributing to the formation of a combustible mixture with the fuel atomized by an injector and burn. Under the action of the valve mechanism, the high-temperature exhaust gas with a certain pressure and flow rate is discharged from the cylinder into the exhaust manifold while influencing the turbine through the turbine shell in a certain direction to make the turbine rotate at a high speed. The finished exhaust gas is finally emitted into the atmosphere. The operating principle is illuminated in Figure 2.  
Figure 2: Operating principle of the diesel engine system.