This report covers a product development project, conducted as a Bachelor thesis for the Innovation- and design engineering program at Karlstad University. The project was conducted during the spring of 2021 and comprises 22.5 hp. The author of this report is student Sanna Kjellberg, the supervisor for the project is Christina Gabrielsson and the examinator is Leo De Vin.  The project follows a traditional product development methodology, with a few modifications regarding the different phases. Following phases was included in the project: Project planning, feasibility study, analysis, concept development, concept selection and final concept. The work is presented in the form of this report, a virtual exhibition and a final presentation. The company who provided the assignment is ProSeal, which are the short term for Professional Sealing Sverige AB. The company has their main office located at Örsholmen, Karlstad and all their suppliers are located in Värmland. The division of the company where the project took place is called Leak Sealing. The process with leak sealing is built on repairing the leak during production, in order to counteract shutdown of the production.  Leak sealing is therefore a very time sensitive process. This project aims to develop the design of the leak sealing clamp in order to reduce delivery time. The project was conducted in collaboration with ProSeal and after a meeting the project took a turn towards design, rather than the dimensions of the product.  The project is therefore a combination of different analysis regarding manufacturing, mounting and the product design. The result is a developed leak sealing clamp with a shorter delivery time, which also is more user-friendly because a decrease of material.

Detta examensarbete utfördes för Scania CV AB. Huvudfokus för arbetet var att analysera sambandet mellan tätningsytors beskaffenhet och uppkomst av mikroläckage i tätningsförband. Tätningsområdet mellan motorblock och cylinderfoder i Scanias V8–motor valdes att undersökas för att analysera möjligheten till att förbättra dagens kravställning till en mer anpassningsbar kravställning för dagens bearbetning. Examensarbete genomfördes i två moment, ett konstruktionsmoment och ett provningsmoment. En testrigg konstruerades och tillverkades för att undersöka det statiska tätningsförbandet mellan motorblock och cylinderfoder. Analysen genomfördes genom att undersöka hur olika ytfinheter av anläggningsytorna för o–ringarna mellan motorblock och cylinderfoder påverkar uppkomsten och kvantiteten av läckage. Detta inleds med att mäta ytjämnhet av ytorna för att sedan utföra ett antal testsekvenser. Den huvudsakliga analysen utfördes på sambandet mellan ytornas beskaffenhet och trycket i systemet, detta genom ett antal testserier utförda med den tillverkade testriggen. Ett förslag på två vibrationskoncept har även tagits fram för framtida vibrationstester. De primära resultaten visade inga spår av läckage på någon av de olika ytfinheterna beroende på enbart tryck som påverkande faktor och med stationär kylarvätska. Även vid uppvärmning av tätningsytor visades inga spår av läckage. Detta resultat av läckage gäller även när enklare vibrationspåverkan utfördes på tätningsförbanden. Läckage uppkom på tätningsförbandet med högst Rz–värde när o-ringar monterats som manipulerats för att simulera slitna packningar. Utifrån de läckagetester som utfördes anses att samtliga ytfinheter vara läckagefria vid olika trycknivåer och att uppkomst av läckage är oberoende av tryckändring som enda påverkande faktor vid statiska förband. Detta gäller även för tryckändring och vibrationer som sker under en begränsad tidsperiod. Tydligt är att skador på packningen, i de här fallet o-ringen har påverkan på uppkomst av läckage. / This master thesis was conducted at NMBC, Scania AB. The main focus of the project was to analyse the relationship between the surface characterization of sealing surfaces and the occurrence of microleakage in sealant joints. The sealing area between the engine block and the cylinder liner was chosen to be investigated to analyse the possibility of improving the current requirements to one that is more adaptable for today’s processing. The master thesis was conducted in two phases, a designing phase and a testing phase. A test rig was designed and manufactured to examine the static sealant joints between the engine block and cylinder liner. The analysis aimed to examine how different surface roughness of the sealing surface for the o-ring affects the occurrence of leakage. The work began with measuring the surface roughness of sealing surfaces as a result of several test sequences. The main analysis was performed on the relationship between the surface roughness and the pressure in the system. A suggestion of two vibration concepts has also been developed for future vibration testing.  The primary results from testing showed no traces of leakage on any of the sealing surfaces when the pressure varied in the static sealant joints. Furthermore, when the sealing surfaces got heated an interesting phenomenon was noticed, pressure rapidly increased in the system while no traces of leakage were found. During vibrations tests, no leakage was detected when a sample vibration test was done. The sealing surface with the highest value of Rz started to leak when the O-ring got replaced with a damaged one.   Based on the tests which were performed, it was considered that all surface roughness passed the leakage tests with no leakage detected when pressure was independently changed in static joints. Furthermore, no leakage was detected when the surfaces where heated and the temperature changed as same as in the vibrations test. A clear indication showed that a damaged O-ring affects the occurrence of leakage.