Analysis and optimization of the Cold Test process for the detection of valve registration anomalies at FPT Industrial

Effectively managing quality issues is crucial for companies that handle large production volumes and face high market demand. These issues are critical and demand meticulous attention, as they can result in significant time and financial losses. Moreover, they can adversely affect customer perception and the overall reliability of the brand. In this context, it becomes imperative to implement fast, effective, and rigorous methodologies and tools. Such measures are essential to streamline the problem-solving process, ensuring that issues are resolved efficiently. This study focuses on the analysis and optimization of the Cold Test process for "NEF" engines at the FPT Industrial plant in Turin. The Cold Test, performed without engine ignition, allows production and product defects to be detected through static and dynamic measurements. This differs from the Long Hot Test and Short Hot Test; carried out with the engine running. An advantage of the analysed test is the possibility of detecting the fault on which this project focuses; the Incorrect Adjustment Of The Intake And Exhaust Valve Tappets. In particular, the focus is on the pressure parameters of the intake and exhaust manifolds. Which are measured on the test bench and are useful in identifying possible engines that have this kind of anomaly. The problem comes from notifications by several customers of noisy engines or engines with an excessive degree of smokiness that, during engine analysis and repair, found the incorrect clearance between valves and rocker arms to be the root cause. In this document there will be a brief introduction to help us better understand the problem faced and the methodology used to solve it. This is followed by three descriptive chapters (the second, the third and the fourth), in which there is useful information to generate the context of the study addressed. The second chapter includes a description of the host company and the specific production line for Turin's main engine family, the NEF. This chapter concludes with a description of the quality department, which is the one at which I was able to carry out the work. In the third chapter there are several classifications of internal combustion engines, which is used immediately afterwards to describe the NEF engine in more detail. There is then a section devoted to the operation of valves and their utility in the engine's operating cycle, which is used to describe deeply the proper functioning of the component that in this project will be analyzed under malfunctioning conditions. The fourth chapter provides a thorough description of the Cold Test and the cells capable of performing it. While the next chapter presents the activity I performed. It begins with the selection of the case study and a description of it. The problem and objective are then defined. The sixth chapter contains the description and analysis of the results of the experiment I conducted followed by a larger scale analysis and a brief statistical study which will lead to the generation of new limits to be set in the test benches in order to obtain greater effectiveness in intercepting the anomaly of incorrect tappet registration. Lastly, the conclusion of the paper contains a description of the expected and anticipated results in terms of improvements generated by the modification made and an introduction to the activities to be carried out subsequent to the work presented in order to bring the generation of the anomaly described to zero.