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Particulate control in car ventilation systems using electrically-charged synthetic filter media are becoming more popular. Adsorption units and low-temperature catalytic systems have been used to control odors and some chemical contaminants in top-of-the-line automobiles. This is a review analyzing these systems, the contaminants found in vehicle environments, and filtration theory. A detailed discussion of experimental work concentrates on overall and fractional filter efficiency and increase in pressure drop with dust loading of charged and uncharged filter media at high aerosol velocity. SAE fine and two natural polydisperse dusts with particles smaller than 5 and 10 μm were used for testing. The health and comfort of car occupants depend on several factors, including air quality. Currently, several car manufacturers offer filtration systems for car interior air.

Environmental concerns over disposable oil filters impact engine oil filter selection for over-the-road trucks and buses. Fleets are extending oil drain intervals and considering alternatives to traditional spin-on filters in an attempt to reduce the costs associated with filter service and disposal. Alternatives to spin-ons, such as screen type separators, are inadequate in terms of particle removal efficiency and contaminant holding capacity. Further, these alternatives typically cost 20 to 40 times more than spin-on filters and are difficult to service. This paper discusses a new line of cleanable, high performance spin-on oil filters. Laboratory tests show that these reusable filters meet or exceed efficiency and capacity specifications set by engine manufacturers. These filters can be cleaned at the normally scheduled service interval without special tools and without removing the filter from the engine.

The development of a particulate filter for a motor vehicle ventilation system is based on filter performance requirements, vehicle's operational environment, available space, filter media properties, and filter element technology. The design process includes analyses of theoretical and empirical models describing filter media performance and aerosol flow in filter housings and through filter elements. Filter media are carefully selected based upon these models and simplified laboratory tests. The filter element design is evaluated in great detail through a series of laboratory and field experiments. This paper shows the process of cabin filter design, including filter media selection and experimental evaluation. Four recently published ISO and SAE test methods are discussed in detail. One of them, the SAE J1669 test procedure, was used to determine full scale filter element performance characteristics.

Environmental concerns over the use and service of traditional disposable oil filters are becoming important in filter selection for off-road equipment. This is particularly true on job sites where “zero” equipment oil leakage is demanded. However, many alternatives to traditional filters do not meet original equipment manufacturers specifications for particle removal efficiency and contaminant holding capacity. This paper discusses the operating features and performance of a new line of oil filters that can be cleaned in-place, on equipment. These new filters meet or exceed the capacity and contaminant removal efficiency of typical high performance synthetic or cellulose disposable filters. Laboratory test results of filtration performance and long term structural integrity are presented. Results of extensive, successful field testing on several types of off-road equipment will also be presented.

Economic, regulatory and environmental concerns are forcing vehicle operators to reevaluate oil filtration practices. Operators can choose from options, including conventional disposable filters, sieves, centrifugal separators and in-place cleanable oil (IPCO) filters. To guide decisions about filtration practices, this paper compares the performance, serviceability, economics and environmental impact of these options. A laboratory evaluation of representative products was conducted. Additional field tests of disposable and IPCO filters for on- and off-road applications were also conducted Disposable and IPCO filters are similar in terms of serviceability and contamination control, but IPCO filters offer environmental and economic advantages

Oil analysis programs are used to monitor the condition of diesel engines. From the standpoint of engine protection, the size and concentration of oil contaminants are as important as their chemical composition. Wear rates are related to the contaminant size distribution in the oil and degree of filtration. Spectroscopic analysis does not provide particle size information and is incapable of measuring the particularly damaging particles larger than 10 μm. Particle size analysis, when used to complement the spectroscopic analysis, provides a better description of the condition of lubricating and transmission oil. Particle size data can be obtained by particle counters, though in the past it was difficult to obtain reliable data. Recent developments overcome many of these difficulties and permit reliable interpretations of particle size data. This allows better decisions to be made concerning the engine and oil conditions and the filtration requirements of the system.

The gravimetric method is commonly used in engine air filtration technology for air cleaner, filter element and filter media testing. An “absolute” filter is employed in-line to collect any dust particles passing through the test filter. Air filter efficiency is calculated by comparing the mass of dust collected by the test filter with that fed to the filter. This method measures only the mass of dust penetrating the filter. It does not provide information on contaminant particle size. Moreover, this method, in many cases, has inadequate precision to distinguish between filters. Both the dust mass and its particle size are needed to estimate engine wear. Therefore, the SAE J726 Air Cleaner Committee initiated work on a test method to measure engine air cleaner fractional efficiency. This paper discusses problems associated with development of the fractional efficiency method for engine air cleaners.