Methodology for restoring dimensional connections when adjusting the valve clearance in the gas distribution mechanism of an automobile internal combustion engine

Abstract

The relevance of research is due to the problems of organizing auto repair production in modern conditions associated with the difficulty of logistics and the high cost of foreign spare parts, which is confirmed by the analysis of domestic and foreign literary sources. Of particular importance in this case are the methods of optimizing the balance of costs for performing repair and restoration actions and replacing defective parts. The purpose of the work is to improve the quality of repair of rolling stock of road transport based on the use of methods for restoring dimensional connections. This study is designed to fill the existing knowledge gap caused by the lack of methods for restoring specific repair links. The use of new parts in repair, along with restored or used ones, necessitates the wider use of methods for optimizing the limit values of wear and recovery processes of dimension chain elements. The materials and methods of research are presented as an example of the development of a technique for restoring the necessary parameters of dimensional connections when adjusting the valve gap value, since the thermal gap in the timing mechanism of an internal combustion engine is an important element affecting the efficiency of the car engine. The scientific novelty of the work lies in the study of two different methods potentially suitable for implementation in the repair industry for restoring dimensional ties while reducing the valve gap by machining the outer or inner contact surfaces of car engine pushers. Studies have been carried out in relation to the decrease in the gap in operating conditions, which is widespread in automobile engines with overhead camshafts, since a decrease in the valve gap to a greater extent than an increase in it affects the efficiency of the machines. The equation of the size chain of the valve group is given, in which the valve gap is the closing link. As a result of sequentially discretely removing the surface layers of the pusher metal at 0.05 mm intervals and measuring the hardness of the surface layers, it has been found that this approach to restoring repair bonds can be recommended for use in auto repair production, with a more preferred method being to adjust the valve clearance by grinding the outer surface of the pushers. The data obtained can serve as the basis for further research in the development of a set of technologies for restoring specific size chains using repair kits that include parts with different manufacturing accuracy or that have been in operation.

Keywords

• car repair plant
• automobile engine
• gas distributing mechanism
• valve clearance
• pusher
• size chain