CAR FILTERS Chapter 2. Types of car filters

1. Types of car filters based on its shape:

1.1 Flat filters: Description and examples: Flat filters are used without frame or (for bigger size) holded by rigid frame or supporting grid. They would be divided onto two variants. Bulk filters are: thermal or chemical bonded nonwovens, needle punch etc... Thin filters are:woven and knitted fabrics, spunbond, meltblown etc.... End use: Cheap filters for common applications (vacuum cleaners, kitchen digestor, paint boxes, cabine filters in cars...), pre-filters for most of air ventilation systems. a) bulk filter b) thin filter Polluted air Clean air FilterSupporting grid

1.2 Pleated filters Description : It is suitable fo high efficient filters. Pleating process leads to bigger filter surface and consequently to smaller pressure drop. It is possible to pleat flat materials, which stiffness and elongation is similar to paper (for example wet-laid nonvoven from glassfibers). It is necessary to hold textile pleats by rigid frame. Filter thickness is usually from 1 to 3 cm. End use: Pre-filters, HEPA filters (High Efficiency Particulate Arrestance) used in air ventilation and air condition systems, Auto cabin air filters, industrial applications, respirators for halfmasks etc... Polluted air Clean air Rigid frame Filter Air flow direction Filter thickness

Examples of pleated filters:

1.3 Pocket filters Description and examples: Principle is similar to pleated filters, only filter thickness is similar to other filter dimensions. Generally it is possible to use nearly all textile fabrics („paper properties“ are not necessary). At first are stitched or bonded each pockets and then it is embed onto the frame. Big dimension of this filter would be disadvantage. End use: Pre-filters for pleated HEPA filters or final filters for less superior industrial applications. Polluted air Clean air Filter

Combination of pleated and pocket filters: Advantage: Maximum filtration area and satisfactory filter proportions End use: Cabin filters,… Polluted air Filter Clean air

1.4 Cartridge filters Description and examples: Flat (bulky) filter or pleated filter is wrapped around the perfored tube. The advantage is smaler dimension of filter with regard to acting surface. End use: Most of filters inside the car, industrial applications etc... Very ofter used for liquid filtration. Container Variants of cartridge filter cross-section Flat (bulky) filterPleated filter Filter Perforated tube Polluted air Clean air

Special type of cartridge filter: Conical filter Advantage: Due to cpecial shape is possible to reach small proportions and big filter area. End use: Oil and fuel filters. Filter container Polluted air Filter Flow direction Cleaned air

Examples of cartridge filters

1.5 Lammellar filters Description: These devices are not common filters. Filtered medium is not flowing through the porous filter but flowing along the filter surface. Filter efficiency is then lower but very low pressure drop is main advantage. Example of end use: Exhaust filters, filters for water. Corrugated paper

2. Types of car filters base on application: 1.Air filters: Cabin filters Engine filters (and Crankcase emission control) Exhaust filters 2.Liquid filters: Oil filters (lube filters) Fuel filters

2.1 Cabin filters Description: cabin filters remove virtually all pollen and other unwanted particles, as well as harmful gases from the air, thus ensuring a better atmosphere inside the vehicle. This is particularly important for people suffering from allergies, asthma, and for children. Types: 1.Particle filters 2.Combined filters with active charcoal Example of Mann-Hummel filter

Typical filter media: Paper, wet-laid textile usually with glass microfibers, meltblown textile, sometimes electrostatically charged. Example of Mann-Hummel cabin filters properties:

2.2 Oil filter Principle: An oil filter is a filter to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil. Oil filters are used in internal-combustion engines in on- and off-road motor vehicles. Types of filters: 1.Mechanical filtration through porous media 2.Magnetical 3.Sedimentation 4.Centrifugal

2.3 Fuel filters A fuel filter is a filter in the fuel line that screens out dirt and rust particles from the fuel. They are normally made into cartridges containing a filter paper. They are found in most internal combustion engines. Fuel filters need to be maintained at regular intervals, although some specially designed filters can be cleaned and reused many times. If a filter is not replaced regularly it may become clogged with contaminants and cause a restriction in the fuel flow, causing an appreciable drop in engine performance as the engine struggles to draw enough fuel to continue running normally. Some filters, especially found on diesel engines, are of a bowl-like design which collect water in the bottom (as water is more dense than diesel). The water can then be drained off by opening a valve in the bottom of the bowl and letting it run out, until the bowl contains only diesel.