Injector sleeve
An injector sleeve adapted to be mounted in a cylinder head of an internal combustion engine, where the injector sleeve comprises a tapered inner surface which constitutes a sealing surface for an injector, where the hardness of the tapered inner surface is higher than hardness of the outer surface of the injector sleeve. The injector sleeve is produced in a cold forming process. The advantage of the invention is that the injector sleeve is provided with a sealing surface for an injector which is harder than the outer surface of the injector sleeve. In this way, a sealing surface for an injector having small tolerances is obtained without further machining, where the outer surface may be turned to the desired dimensions.
1. Injector sleeve adapted to be mounted in a cylinder head of an internal combustion engine, having a nozzle portion, a mid portion and an upper portion, where the mid portion comprises a tapered inner surface which constitutes a sealing surface for an injector, wherein the hardness of the tapered inner surface is higher than the hardness of the outer surface of the injector sleeve.
2. Injector sleeve according to claim 1 , wherein the hardness of the tapered sealing surface is at least 10% higher than the hardness in a plane that is positioned 0.5 mm into the material from the tapered sealing surface.
3. Injector sleeve according to claim 1 , wherein the hardness of the tapered sealing surface is higher than 350 HK.
4. Injector sleeve according to claim 3 , wherein the hardness of the material at a plane that is positioned 0.5 mm into the material from the tapered sealing surface is at least 350 HK.
5. Injector sleeve according to claim 1 , wherein the roundness of the tapered sealing surface is better than 10 micrometers.
6. Injector sleeve according to claim 1 , wherein the surface finish of the tapered sealing surface is better than 2 micrometer.
7. Injector sleeve according to claim 1 , wherein the surface finish of the tapered sealing surface is better than 1 micrometer.
8. Injector sleeve according to claim 1 , wherein the nozzle portion comprises an inwardly protruding collar adapted to be flared out towards an opening surface of the cylinder head after the injector sleeve is mounted in the cylinder head.
9. Injector sleeve according to claim 1 , wherein a lower surface of the mid portion is provided with at least one groove.
10. Injector sleeve according to claim 9 , wherein the at least one groove is adapted to hold a sealing compound when the injector sleeve is mounted in the cylinder head.
11. Injector sleeve according to claim 1 , wherein the upper portion comprises a groove adapted to hold a sealing ring when the injector sleeve is mounted in the cylinder head.
12. Injector sleeve according to claim 1 , wherein the injector sleeve is produced in a cold forming process.
13. Injector sleeve according to claim 12 , wherein the injector sleeve is produced in two squeezing steps.
14. Injector sleeve according to claim 12 , wherein the outer surface of the injector sleeve is turned after the cold forming process.
15. Internal combustion engine, comprising at least one injector sleeve according to claim 1 .