As an important part of the valve train of diesel generator set, valve group includes many parts, such as valve, valve seat, valve spring, valve guide, spring seat and so on.

氣門座是與氣門密封錐面相配合的支承面它與氣門共同保證密封性能，同時它還要把氣門頭部的熱量傳遞出去。

The valve seat is a bearing surface matched with the valve sealing cone. It ensures the sealing performance together with the valve, and it also transfers the heat of the valve head.

氣門座可以直接在汽缸蓋或汽缸體上加工而成。為了提高氣門座表面的耐磨性，有時采用耐熱鋼、球墨鑄鐵或合金鑄鐵制成單獨的零件，然后壓入相應(yīng)的孔中。這個零件即稱為氣門座圈。鋁制汽缸蓋或汽缸體進、排氣門都必須采用氣門座圈。對于強化內(nèi)燃機，排氣門熱負(fù)荷高、磨損嚴(yán)重，所以排氣門座通常都采用氣門座圈。有的增壓內(nèi)燃機，由于進氣管中無真空度，所以進氣門處得不到機油的潤滑而排氣門處由于有廢氣中的油煙可起到潤滑作用，所以進氣門座有座圈，而排氣門座則沒有。

The valve seat can be machined directly on the cylinder head or cylinder block. In order to improve the wear resistance of the valve seat surface, separate parts are sometimes made of heat-resistant steel, nodular cast iron or alloy cast iron, and then pressed into the corresponding holes. This part is called the valve seat ring. Aluminum cylinder head or cylinder block inlet and exhaust valves must adopt valve seat ring. For enhanced internal combustion engines, the exhaust valve has high heat load and serious wear, so the exhaust valve seat usually adopts valve seat ring. In some turbocharged internal combustion engines, there is no vacuum in the intake pipe, so the intake valve can not be lubricated by engine oil, while the exhaust valve can be lubricated by the oil fume in the exhaust gas, so the intake valve seat has a seat ring, while the exhaust valve seat does not.

采用氣門座圈的優(yōu)點是提高了座面的耐磨和壽命，更換和維修也比較方便。缺點是傳熱條件差，加工要求高，氣門座圈如工作時松脫則會造成事故。

The valve seat ring has the advantages of improving the wear resistance and service life of the seat surface, and it is also convenient to replace and maintain. The disadvantages are poor heat transfer conditions and high processing requirements. If the valve seat ring is loose during operation, it will cause accidents.

氣門座圈的外表面有制成圓錐形或圓柱形兩種。錐形表面壓入座圈孔時，必須按規(guī)定的沖力將其壓緊。氣門座圈如壓入鋁合金汽缸中時，其配合表面常制成溝槽，當(dāng)氣門座圈壓入后，少量鋁金屬會擠入溝槽中，在對氣門座孔擴口時也會促使鋁合金擠入，以提高座圈在座孔中的緊固程度，防止松脫

The outer surface of the valve seat ring can be made into a cone or a cylinder. When the conical surface is pressed into the seat ring hole, it must be pressed according to the specified impulse. When the valve seat ring is pressed into the aluminum alloy cylinder, its mating surface is often made into a groove. When the valve seat ring is pressed in, a small amount of aluminum metal will squeeze into the groove. When the valve seat hole is flared, it will also promote the aluminum alloy to squeeze in, so as to improve the fastening degree of the seat ring in the seat hole and prevent loosening

氣門座緊壓在汽缸蓋的座孔中，磨損后以更換。氣門錐面是氣門與氣門座之間的配合面，氣門的密封性就是依靠兩個表面嚴(yán)密貼合來保證的。為了保證密封，每個氣門和氣門座都要配對研磨，研磨后氣門不能互換。

The valve seat is tightly pressed in the seat hole of the cylinder head and can be replaced after wear. The valve cone is the mating surface between the valve and the valve seat. The tightness of the valve depends on the close fitting of the two surfaces. In order to ensure sealing, each valve and valve seat shall be matched and ground. After grinding, the valves cannot be interchanged.