Automotive Engine Air Cleaners – Maintenance Investigations MARIUS TOMA Automotive Engineering Department University POLITEHNICA of Bucharest 313, Splaiul Independentei, Bucharest ROMANIA mariusflorin.toma@yahoo.com Abstract: - The dust particles from the atmospheric air that pass through the air cleaners of the internal combustion engines heavily influence their wear. The main purpose of air filters is to reduce the quantity of particles that reach the burning chambers of internal combustion engines. To achieve this purpose, an increased importance must be given to maintenance activity. The replacement of air cleaners must be made by understanding the implications of their premature or tardy replacement over the life of the engine. In this paper were tested air cleaners of the same type measuring the values for: pressure drop of several air cleaners at the time of their replacement; filtration efficiency of new and used filters; and the size of dust particles that pass through new and used air cleaners. This paper aims to highlight the extent to which the replacement of air cleaners based on the distance travelled by the car or the usage time (in kilometres or years) is appropriate for protecting internal combustion engines. Key-Words: - air cleaners, pressure drop, efficiency, particle size, replacement period. 1 Introduction The life of an internal combustion engine is influenced by a multitude of parameters. These include the contamination of the intake air with mineral, very tough impurities with sharp irregular shapes. The penetration of impurities inside the burning chamber and forward to the lubricant reduces the lifetime of the engine. In paper [1] is specified that 80% of the cases, the engines’ lifetime is limited by the consequences of the wear. Atmospheric air contains lots of particles with physical-chemical properties influenced by the geographic region, clime, season, urban or extra urban area [2], [3], [4]. The main sources of the particles from the roads are: industrial ones; dust from the agricultural fields carried by the wind; particles resulted from road wear and motor vehicles components wear; exhaust particles from the engines [5]. The air admission system is the main source of impurities (contaminants) that reach inside the engine. Choice and maintenance of the air cleaners are important activities in reaching a longer lifetime of the engines, ensuring high levels of energetic, economic and reliability performances. The performances of the air cleaners are evaluated by the next main criteria: - a high filtering efficiency over the entire air cleaner’s service life; - reduced gaso-dynamic resistances over the entire service life; - high storage capacity of the impurities. Next some terms are defined: - efficiency - ability of the air cleaner or the unit to remove contaminant under specified test conditions, [6]; - absolute filter—the filter downstream of the unit under test to retain the contaminant passed by the unit under test [7]; - differential pressure [6] (pressure drop [7])- difference in static pressure measured immediately upstream and downstream of the unit under test. 2 Literature references In paper [8] is defined the service life: The useful functional life of an engine air induction filter, in order to protect the engine without any appreciable performance degradation. Setting the maintenance intervals for the air cleaners should be made considering the construction- function and exploitation conditions of the motor vehicles. The main replacement criteria are: - the distances covered with the same air cleaner (the main criteria); - the usage period; Recent Advances in Civil Engineering and Mechanics ISBN: 978-960-474-403-9 153