这些问题的发生，在4.5L发动机上，这种发动机本身震动表现不好，而且从

The occurrence of these problems, on the 4.5L engine, the vibration performance of the engine itself is not good, and it can be seen from the report that some of them are caused by the pulling of the fan belt, and some are caused by the pulling of the air-conditioning compressor belt. These are all related to the design of the entire pulley train. According to my communication with Cummins, there are two factors for this kind of failure. 1. The force of the crankshaft needs to take into account the 360-degree force of the crankshaft and needs to meet the requirements of AEB. 2. It is related to the vibration performance of the entire engine after starting, which is ultimately reflected in the index of the moment of inertia of the crankshaft. Different engines have different limit requirements for the moment of inertia. And this agrees with the vibration behavior of the wheel train and engine. <br>The weight of the pulley is not the main reason, and the dynamic balance of the single pulley is only a secondary factor, because even if the dynamic balance of the pulley is good, but it is pulled by the belt very much, such a failure will still occur.

For the occurrence of these problems, on the 4.5L engine, the vibration performance of the engine itself is not good, and it can be seen from the report that some are caused by the pulling of the fan belt and some are caused by the pulling of the air conditioning compressor belt. These are related to the design of the whole belt pulley system. According to my communication with Cummins, there are two factors causing this kind of fault: 1. The stress of the crankshaft, which needs to consider the 360 degree stress of the crankshaft and meet the requirements of AEB. 2. It is related to the vibration performance of the whole engine after starting, which is finally reflected in the index of crankshaft moment of inertia. Different engines have different limit requirements for moment of inertia. This is related to the vibration performance of the gear train and engine.<br>The weight of the pulley is not the main reason, and the dynamic balance of a single pulley is only a secondary factor, because even if the dynamic balance of the pulley is very good, but it is pulled heavily by the belt, such a fault will occur.

These problems happen on the 4.5L engine, and the vibration performance of the engine itself is not good. From the report, we can see that some of these problems are caused by the pulling of the fan belt and some by the pulling of the air conditioner compressor belt. These are all related to the design of the whole belt pulley system. According to my communication with Cummins, there are two reasons for this failure. 1. The stress of the crankshaft needs to consider the 360-degree stress of the crankshaft and meet the requirements of AEB. 2. It is related to the performance of the whole engine vibration after starting, which is finally reflected in the index of the moment of inertia of the crankshaft. Different engine moments of inertia have different limit requirements. This agreement is related to the vibration performance of gear train and engine. The weight of the pulley is not the main reason, and the dynamic balance of the individual pulley is only a secondary factor, because even if the pulley has a good dynamic balance, but it is pulled by the belt badly, such a failure will occur as well.