求翻译：　若安装喷油嘴隔热护套时未清洗干净，喷油嘴头和隔热护套有间隙，将使燃气进入间隙内，造成隔热和散热效果降低，喷油嘴和隔热护套烧熔。若隔热护套安装过紧，喷油嘴将产生附加应力，在热交变负荷和燃油喷射高压负荷的共同作用下，会使喷油嘴头部断裂，针阀卡滞而滴油。此外，若维修时漏装隔热护套，喷油嘴伸入燃烧室超过汽缸盖底下4 mm以上，将使喷油嘴吸收的热量增加，使喷油嘴烧熔。是什么意思？

If the installation nozzle insulation jacket is not cleaned, the nozzle head and the insulation sheath gap, and will allow gas to enter the gap, resulting in reduced insulation and thermal effects, nozzle and the insulating sheath Shaorong . Insulation sheathing installation tight nozzle will produc