发帖原因：车坛网友--1234567-友情提示这个部件，于是去查了查，再接着就有了这个帖子！
What does a VCT or VVT Solenoid Do?
VCT or Variable Cam Timing solenoid is a device used in modern engines to change camshaft position timing in relevance to engine speed and engine timing allowing the engine to produce more horsepower without adding excessive overlap to the camshaft design.
The way the VCT Solenoid works is as follows:
The VCT solenoid works with oil pressure, it receives a signal from the ECM when the camshaft needs to be rotated either in the advanced mode or retarded mode depending on engine load and speed. The VCT solenoid is able to accomplish that by altering the oil flow in the passages that lead to the cam phase(s), there are passages to advance the valve timing (open the valves earlier), and passages that direct the oil to retard the valve timing (open them later)
What is the Purpose of the VVT System?
The purpose of the VCT or Variable Cam Timing system is to allow the engine to move larger volumes of air in and out of the cylinders to generate maximum horsepower.
Vehicles with DOHC (Dual Overhead Cam) engines usually have two VCT solenoids mounted in each cylinder head, one for each camshaft, allowing the Engine Control Computer to activate each VCT timing mechanism in each Camshaft separately.
NOTE: The Cam phase is mounted on the front of the camshaft(s) it is driven by the engine’s timing chain or timing belt depending on the engine’s design.
How Variable Valve Timing Works
Oil Control Valve=OCV
适用车型：好多好多，各个车系这个部件的称谓略有不同，有的这个电磁阀和滤网合二为一，具体细节请自查！
宝马车系这个部件叫：Vanos
这有个链接可参考 2008 BMW 750Li E66 Vanos solenoid 清洗作业
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前后Bank的VVT电磁阀，和这个电磁阀垂直交叉的底部就是这个电磁阀的过滤网(Strainer)
上面的是后BANK的电磁阀，下面的是前BANK的电磁阀
略去N多拆卸部件，主要是空滤盒子和若干橡胶软管，切记连接配对不要搞错！
红色箭头为前BANK VVT电磁阀 紧固螺栓10mm
黄色箭头为前BANK VVT电磁阀的Strainer 紧固螺栓14mm
抵近拍照，红色为电磁阀及紧固螺栓，黄色为过滤网螺栓，附近螺栓一堆，可要先搞清楚哪个是那个！
在这个位置用丝锥轻轻地撬一下就下来了
看着还不错，没啥固态杂质
没有浅的14mm socket,只能找到这个比较深的impact socket，所以多卸了些部件及管件！
在拔电磁阀的之前就要垫块破布啥的接着机油，这两个东西卸下都会有少许机油溢出
也还不错哦！没有固状沉淀杂质
后面就是用汽油给他们都泡个澡，清洗干净吹干，其实也不脏！安装注意Strainer是有安装方向的，小头在外。每次只清洗一个，前后电磁阀不要混用！！！
后面3个缸的电磁阀（红色箭头）及过滤网（黄色箭头）
这些是网上搜来的，看看啥叫那个脏！
结论：正确使用标称机油及按时按里程定期更换机油是保障机油系统内部清洁的关键！
