1 Cooling Fan Failure Mode Analysis to Enable Development of Automotive ECU Fan Health Monitoring System Jacqueline Del Gatto 1 , Alaeddin Bani Milhim 2 , and Hossein Sadjadi 3 1-3 General Motors Canadian Technical Centre, Markham, Ontario, L3R 4H8, Canada jacqueline.p.delgatto@gm.com alaeddin.banimilhim@gm.com hossein.sadjadi@gm.com ABSTRACT Electronic Control Units (ECUs) are widely used in the automotive industry. Recent efforts to enable enhanced and automated driving requires these ECUs to process and execute computationally expensive algorithms. With these developments, the ECUs now have a higher computing power and thus are at a greater risk of overheating that can limit the availability of the essential functionalities in the vehicle. Current passive cooling may no longer be sufficient to mitigate high operating temperatures, and a cooling fan system is preferred for ECU thermal management. The fan health status monitoring is therefore critical to ensure ECU availability and reliability for vehicle operation. Traditionally, fan failures are only detected by comparing the actual fan speed against the commanded speed; however, to enable early degradation detection and prognostics, a more advanced health monitoring system is required. This paper explores fan failure mode analysis and fault injection to enable the development of prognostics. The data collection and fault injection methods were designed to capture both internal (such as motor and ball bearing) and external (such as cracking of the outer casing) failure modes. For example, the fans were exposed to multiple environmental conditions, such as dust, humidity, and heat. These conditions can potentially cause both internal and external failures. The data collection was conducted with the fans running in a standalone setup, being controlled by external equipment to ensure that the electronic input values were known. After running tests for 32 days, sufficient data was collected to enable the degradation modelling. The data will contribute to the development of a predictive algorithm which will estimate the state of health of the fan based on its performance over time. This paper will discuss the failure modes and the data collection aspects. 1. INTRODUCTION Electronic Control Units (ECUs) play a vital role in ensuring the proper functioning of various vehicle subsystems within the automotive industry. ECUs are cooled using passive methods by physically designing the component to prevent excessive heat accumulation before it becomes detrimental to the performance. The advancements in autonomous driving have led to the emergency of highly sophisticated ECUs, necessitating more advanced thermal management solutions beyond passive cooling methods. To maintain the availability of autonomous driving features, it is imperative to employ a more efficient cooling method for these intricate ECUs, as they are prone to rapid overheating. Such a cooling method can use a small fan, similar to those used in small electronics such as computers and power supplies. Extensive research has been conducted on small electronic fans, resulting in a comprehensive understanding of their characteristics and various failure modes (Schroeder & Gibson, 2007; Jin, Ma, Chow, & Pecht, 2012). Studies have been conducted on the failure frequencies of various small electronic components, and it has been established that the fan ranks among the top 10 components prone to failure (Schroeder & Gibson, 2007). Fan failure criteria and mechanical failures have been thoroughly studied, leading to the development of multiple methods for predicting the life expectancy of fans. These methods have been thoroughly compared to identify the most effective approach for accurately estimating fan life expectancy (Jin, Ma, Chow, & Pecht, 2012). Both external and internal failure modes have separately identified for fans, encompassing issues such as internal ball bearing failures, motor malfunctions, electronic faults, and outer casing damage caused by environmental factors. A physics-of-failure approach has been developed based on these failure modes, allowing for the estimation of fan life expectancy. Life-expectancy calculations have been employed to assess the lifespan of ball bearings and the accompanied lubricant. Furthermore, the impact of these failure modes on fan functionality has been extensively Jacqueline Del Gatto et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 3.0 United States License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.