Withstanding the Pressure, Surpassing the Standard
As emission norms get stricter, engines lighter and more efficient, and customers more demanding, pistons have to work reliably under combustion temperatures reaching from 1000°C to 2500°C, and ignition pressures of up to 250 bar. Additionally, OEMs are offering million-mile warranties to end users.To keep up with these demands, a variety of new materials and treatments are being developed by OEM vendors.
Garima Global works with such leading vendors of pistons in India to manufacture cutting edge pistons for the aftermarket industry. Our customers also trust us to source pistons and piston rings, and assemble them with our cylinder liners to make liner-piston kit sets. Garima Global supplies these AutoGRACE® brand pistons to discerning customers worldwide.
Pistons serve three important functions in an IC engine:
Size Range of Piston in AutoGRACE® Brand
Garima Global supplies components for a wide variety of on-road, off-road, industrial and stationary applications such as: automotive (light duty) and light commercial, trucks (heavy duty), tractors (agricultural), earthmoving and construction machinery, generators, irrigation pumps, and defence / special purpose vehicles.
The brands for which we manufacture and export aftermarket products are Caterpillar, Chevrolet, Chrysler, Citroen, Cummins, Daewoo, DAF, Daihatsu, Detroit Diesel, Deutz, Fiat, Ford, Hino, Honda, Hyundai, International, Isuzu, Iveco, John Deere, Kamaz, Kia, Komatsu, Kubota, Land Rover, Leyland, Lister Petter, Lombardini, Mack, Mahindra, MAN, Massey Ferguson, Mazda, Mercedes Benz, Mitsubishi, Navistar, Nissan, Onan, Perkins, Peugeot, Renault, Scania, Suzuki, Tata, Tatra, Toyota, Ursus, UTB, Volvo, Yanmar and Zetor, amongst others.
Garima Global also export parts for air-brake compressors like Wabco, Bendix, Knorr, Cummins, Clayton Dewandre, Mercedes, Midland etc.
Garima Global has developed an extensive range of components for engine, braking, transmission, suspension, steering, chassis, electrical, lighting and other automotive sub-systems. To assist our customers with choosing the right product for their requirements we have published comprehensive catalogs with engine / vehicle models, interchange with references of OEMs and other popular aftermarket brands, fitment dimensions and other technical data. We strongly encourage you to contact us with your specific requirements so that we can email you the relevant catalogs, and we look forward to starting a mutually beneficial business relationship with you soon!
Depending on the material they are made of, and the kind of application they serve, AutoGRACE® pistons are available in a very wide and complete range covering different types.
The crown and the body of the piston may incorporate various design elements to serve a wide variety of purposes.
Since monometal pistons usually exhibit high thermal expansion, steel or ceramic struts are cast into the piston boss area especially when used in cast iron engine blocks. This restricts the expansion of the piston thus enabling smaller piston-block clearance.
Diesel engines operate at higher temperatures and pressures than gasoline engines, which causes excessive loads on the piston crown. To re-inforce the top one or two ring grooves, Ni-resist or ALFIN ring carriers are cast into the piston. These ring carriers made from high-strength, austenitic cast iron increase the wear resistance and fatigue resistance of the grooves at elevated temperatures. Dual Ni-Resist, or ring carriers with two ring grooves are also used in particularly heavy-duty engines.
In turbo-charged / super-charged / inter-cooled / after-cooled engines, thermal loads tend to be even higher. To counter these, a cooling gallery may be cast into the crown of the piston using a salt core. Lubricating oil is sprayed into this gallery from the crankcase which reduces the temperature of the bowl rim, top land and ring grooves, thus guaranteeing longer life.
Pistons used in engines that operate under especially high loads require a bushing, similar to a con rod small end bushing, to be installed on the piston pin bore. This bushing serves to improve lubrication between pin and piston.
There are literally thousands of piston crown designs:
Allow the piston to approach extremely close to the cylinder head without hitting the valves thus maximizing compression ratio.
Are especially prevalent in diesel pistons since these engines do not have the ignition phase. Cavities of various sizes and shapes are cast / machined into the piston crown inside which combustion occurs. The geometry of the bowl is designed to maximise combustion thus producing higher power.
To “swirl and squish” or direct the fuel-air mixture are cast / machined into the piston head. They increase the turbulence of air-fuel mix as the piston approaches TDC which causes better mixing and more complete combustion, again maximizing power output.
AutoGRACE® pistons have been developed with the exact head geometry as per OEM specifications, thus ensuring your engine gives the same power output and efficiency as a brand new engine!
Vast majority of the applications utilize aluminium pistons due to their light weight, good thermal conductivity and structural rigidity. Since pistons reciprocate within the cylinder liner 800-8000 times per minute their light weight lowers inertia, decreases load on the connecting rod, and increases engine efficiency and safety. Also the high thermal conductivity of aluminium helps dissipate the heat generated from combustion into the block. Good machinability and simple casting techniques are an added advantage of this material from the production standpoint.
These constitute the simplest design, material used is high temperature resistant aluminium alloy cast using gravity die casting process. They are competitively priced, can be manufactured in smaller production lots and offer adequate performance for lower performance engines.
These basic pistons are enhanced with certain elements to reduce their thermal expansion and improve rigidity, strength, wear resistance etc. as summarized below.
Most commonly used alloy with 12% Si + 1% approximately of Cu, Ni and Mg. Provides a balanced combination of strength and high-temperature resistance.
Developed for higher strength at elevated temperatures with higher percentages of Cu and Ni. Used in especially heavy duty engines.
With Si ranging from 18% to 24%, these alloys offer lower thermal expansion and high wear resistance, but at the cost of lower strength. They are used in lighter, high-speed engines like light-duty automotive applications.
Certain heavy-duty engines utilize the articulated or two-piece piston having a forged steel crown assembled with a light-weight aluminium skirt using the piston pin as the connecting element. The lower coefficient of thermal expansion of steel enables closer gap between piston and liner thus improving its sealing capability, while its strength allows greater ignition loads to be transferred to the crankshaft without warpage. The light aluminium skirt fulfils the guiding function while lowering the inertial losses in the engine. AutoGRACE® brand articulated pistons will stand up to the toughest operating environments to give you complete peace of mind.
Though virtually all IC engine manufacturers have replaced cast iron pistons with aluminium ones, some air-brake compressor OEMs still favour CI pistons as they are much more economical and adequately serve the lower temperature regime of air-compressors. Since CI has a lower coefficient of thermal expansion, these pistons can be manufactured with a much closer gap between piston and liner, improving sealing, which is a vital factor in any compressor application. Also, block life is increased substantially by using a CI piston as compared to aluminium pistons. Garima Global manufactures premium quality cast iron pistons for all compressor applications.
Other than material, AutoGRACE® brand pistons come with a variety of coatings and surface treatments to reduce frictional losses and enhance engine life. Coatings also address the traditional problem observed in aluminium pistons where the harder cast iron particles from the block or liner get embedded into the softer aluminium skirt and subsequently cause abnormal wear of liner or block. Some of these include:
Coating the outer surface of the piston with tin electrolytically improves its initial run-in performance.
Molybdenum Disulphide (MoS2) is screen printed on to the piston skirt, increasing the skirt hardness and enhancing life of the cylinder liner.
Intermediate coating to enhance the adhesion of graphite coating onto the base aluminium metal.
Enhances lubrication and aids in cold start, thus reducing scuffing of piston skirt.
AutoGRACE® pistons are manufactured by OEM and OES factories across India that adhere to the higher quality specifications. Additionally they are tested by Garima Global at our in-house lab before dispatch to our discerning customers globally.
Aluminium pistons, which form the bulk of our business, start their journey in world-class foundries that produce castings of appropriate material composition, physical properties and microstructure.
These blanks are then machined on latest and automated machining lines. Camless CNC Oval Turning Centers are used to generate an accurate symmetrical as well as asymmetrical profiles as well as accurate combustion bowl shape and position.
Finally any of the below listed surface treatments are available to further enhance the functional characteristics, storage life, protect against corrosion and achieve superior running-in performance of the pistons.
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