What is valve depression?
In the field of automotive maintenance and engine performance optimization,Valve depressionIt is a key parameter that directly affects the sealing and power output of the engine. This article will explain in detail the definition of valve droop, measurement methods and its impact on the engine. It will also provide readers with a comprehensive technical analysis based on hot topics and hot content in the past 10 days.
1. Definition of valve subsidence
Valve subsidence refers to the vertical distance between the valve head and the valve seat when the valve is closed. This parameter reflects the degree of wear of the valve and valve seat, usually in millimeters (mm). When the valve or valve seat is severely worn, the valve sinkage will increase, resulting in a decrease in the engine's compression ratio, insufficient power, and even air leakage.
2. Measuring method of valve subsidence
Measuring valve sag requires the use of a special tool, such as a dial indicator or depth gauge. The following are common measurement steps:
| step | Operating Instructions |
|---|---|
| 1 | Remove the cylinder head and make sure the valves are closed. |
| 2 | Fix the dial indicator on the cylinder head and align the probe vertically with the valve head. |
| 3 | Record the initial reading, then lightly compress the valve and record the reading after it sinks. |
| 4 | Calculate the difference between the two readings, which is the valve depression. |
3. The impact of valve depression on the engine
Changes in valve depression will directly affect engine performance and life. Here are its main impacts:
| Impact type | Specific performance |
|---|---|
| Compression ratio drops | Excessive valve depression will increase the combustion chamber volume, reduce the compression ratio, and affect power output. |
| Valve sealing deteriorates | When wear is severe, the valve and valve seat cannot fully fit, resulting in air leakage. |
| Increased fuel consumption | Engine efficiency decreases and fuel economy deteriorates. |
| Emissions exceeding standards | The amount of incompletely burned mixture increases and exhaust emissions worsen. |
4. The correlation between hot topics in the past 10 days and the amount of valve subsidence
Recently, the technical comparison between new energy vehicles and traditional fuel vehicles has become a hot topic. The following are relevant hot topics:
| hot topics | Correlation with valve depression |
|---|---|
| New energy vehicle sales growth | Pure electric vehicles have no valve structure, but hybrid models still need to pay attention to the amount of valve depression. |
| Fuel vehicle engine technology upgrade | New materials and valve designs reduce valve sag and extend engine life. |
| Implementation of National VI Emission Standards | Valve sealing is critical to emissions, and excessive sinkage may result in failed testing. |
5. How to repair the problem of excessive valve sinking
When the valve subsidence exceeds the limit value specified by the manufacturer, the following repair measures need to be taken:
| Fix | Applicable scenarios |
|---|---|
| grinding valve seats | When slightly worn, grinding is used to restore the fit between the valve and the valve seat. |
| Replace valve | When the valve head is severely worn, replace the valve directly with a new one. |
| Inlaid valve seat ring | When the valve seat is severely worn, insert a new seat ring to restore the standard subsidence. |
6. Summary
The amount of valve depression is an important parameter in engine maintenance, which directly affects the power, economy and emission performance of the vehicle. Regular inspection and repair of excessive valve subsidence can effectively extend engine life. With the continuous development of automotive technology, the application of new materials and new processes will further improve the reliability of the valve system.
Recent hot topics show that the rise of new energy vehicles has not completely replaced traditional fuel vehicles, but has promoted the optimization of engine technology. Whether it is a fuel vehicle or a hybrid vehicle, the management of valve depression is still the key to ensuring efficient engine operation.
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