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AutoGRACE®
Piston Rings

The pinnacle of performance for your engine

As any expert knows, piston rings are the single most important element in any liner-piston-ring assembly that affects oil consumption, power generation and a host of other factors in an internal combustion engine. Wise customers never compromise on the quality of piston rings hence Garima Global supplies premium AutoGRACE® brand piston rings to customers globally.

PRODUCT

Piston rings are metallic gaskets that serve three important functions in an IC engine:

  1. SEALING: Prevent the combustion gases from escaping into the crankcase.
  2. HEAT DISSIPATION: Transfer heat away from the combustion chamber and into the cooling media, and
  3. OIL REGULATION: The oil ring, in particular, controls the volume of oil present on the cylinder liner surface.

PRODUCT RANGE

Garima Global has developed an extensive range with the leading manufacturers of piston rings in India. We specialize in developing custom made rings according to the requirements of our customers.

Size Range of Piston Rings in AutoGRACE® Brand

SPECIFICATION FROM TO
Diameter (mm) 20.0 400.0
Height (mm) 0.5 5.0

APPLICATIONS

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.

PRODUCT CATALOG

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!

TYPES OF PISTONS RINGS

Piston rings have been the focus of intensive R&D by OEMs for a sustained period of IC engine history. A plethora of designs have been tried and tested to fit different applications, a representation of which is presented below.

FUNCTION

Compression Rings or Top Rings

In a typical three-ring automotive piston, the top ring performs the sealing function and also dissipates heat away from the combustion chamber.

Scraper Rings or Intermediate Rings

Usually second from top, these rings help to seal the combustion gases in, while scraping off excess oil from the liner surface.

Oil Control Rings

The oil ring, in combination with the scraper ring above it, regulates the oil film on the liner surface so that there is minimal friction between the rings and the liner.

DESIGN

CROSS-SECTION

Piston rings have been designed with numerous cross sections – Rectangular, Bevelled, Double Trapezoid / Keystone, Single Trapezoid / Keystone, Taper Face, With Inside Chamfer, Napier, L-shaped – to serve the particular design requirements of various engines.

OIL SLOTS AND MULTI-PIECE DESIGN

Oil control rings also incorporate slots to regulate the flow of oil and could be multi-piece rings consisting of a 2-piece design with an outer ring that is spring loaded on the inside or an expander-backed 3-piece design.

PERIPHERAL FACE SHAPE

The peripheral surface is further shaped into a straight face, barrel face, asymmetric barrel, taper face or a taper face rounded / lapped partially.

POSITIVE-TWIST AND NEGATIVE-TWIST RINGS

The top inside edge may be bevelled or stepped to achieve a “positive twist” in the ring, promoting better oil consumption, while creating a bevel / step in the bottom inside edge creates a “negative twist” in the ring which promotes better sealing against the liner wall.

RING GAP DESIGN AND INSTALLATION CARE

While installing rings, care should be taken that the rings gaps of all the rings do not line up with each other, or this will create a passageway for combustion gases to escape into the crankcase. To further fool-proof against this eventuality, Convex or Angle Step Joints are used which provide improved sealing as compared to the most popular and simple Butt Joint Design. Other designs like Hook Joints, Overlap Joints and Angle Joints provide no advantage in terms of sealing and are suitable for hydraulic / compressor / automatic transmission applications.

MATERIAL

Nodular / Spheroidal Graphite Iron

Alloyed and hardened SG Iron is the material of choice for performance compression rings due to its hardness and high resistance to flexure.

Grey Cast Iron

For compression rings in low speed engines as well as scraper and oil rings, alloyed and unhardened Grey Cast Iron usually serves the purpose due to its good wear-in and emergency running properties.

Steel

For especially low ring heights or in diesel engines with steep pressure gradient, steel is the material of choice. It is also preferred for spacers and rails in three-piece oil control rings due to its higher breaking strength.

Other Materials

Phospho Bronze, Sintered Iron and Sintered Bronze are also being used for specific applications.

It is of utmost importance that the material of the liners and rings be compatible to prevent premature wear and tear of either one of these components. Hence we recommend our customers to use AutoGRACE® brand piston rings with AutoGRACE® brand cylinder liners to optimize the life of their engines.

COATINGS

Below are some of the main coatings developed for the running face of the piston rings. These coatings in general increase wear resistance of the rings and also generate lower wear of liner surface.

Chromium Plating and Chromium Inlay

Hard chrome is plated or deposited into a groove on the ring circumference. This prolongs the ring life but may prematurely wear out the liner if its material is not compatible with the ring.

Thermal Spray Coatings

These can withstand metal-to-metal wear better than hard coatings like Chromium, and hence have better anti-scuffing properties. The important ones are:

HVOF (High Velocity Oxy-Fuel)
Metal-Ceramic Composite
Plasma-Molybdenum Inlay

Physical Vapor Deposition (PVD)

PVD coatings follow base metal contour perfectly and are extremely scuffing and wear-resistant.

Diamond-Like Carbon (DLC)

DLC coatings help reduce friction between ring and liner.

Gas Nitriding / Salt Nitriding / Nitrocarburizing

Usually used in rings for gasoline engines to improve scuff behaviour and improve wear resistance.

SURFACE TREATMENTS

To improve performance of the ring early in its lifecycle after installation, and their cosmetic appeal, as well as to enhance shelf life by protecting the rings against corrosion, a variety of surface treatments have been developed, some of the important ones being:

Parkerizing / Phosphating / Phosphatizing

A 2-5 micron layer of phosphate crystals is deposited which improves the run-in characteristics of the ring since it is softer than the base ring material.

Black Oxiding

An excellent and economical anti-corrosion treatment.

Tin and Copper Plating

Reduce the surface hardness and have a lubricating effect when the tin or copper melts due to combustion temperatures.

Chemical Passivation Processes

Improve corrosion resistance and increase fatigue strength.

PTFE Coating

Used in piston rings for industrial / hydraulic applications where loss of lubrication may be anticipated.

MANUFACTURING

PROCESS

AutoGRACE® piston rings are manufactured by leading OEM and OES factories across India that adhere to the highest quality specifications.

The grey cast iron rings are either individually cast or cut from cylindrical castings and then ground on their axial faces. Double cam turning process is used to shape the inner and outer diameters simultaneously using copy turning technique after which the ring gap is cut to achieve the desired free shape of the piston ring. Once installed in the cylinder the rings achieve the defined radial pressure distribution and form a light-tight seal on its outer diameter with the liner surface.

Steel rings are manufactured from steel wires of defined material properties and cross-sections, usually imported from Japan and Taiwan.

TESTING

Garima Global tests piston rings at the in-house lab before dispatch to our discerning customers globally on the following important parameters, among others:

  • Chemical Composition
  • Dimensional Specifications (Free Ring Gap, Installed Ring Gap, Axial Width, Radial Width, Cross Sectional Parameters like Keystone Angle, Taper Angle etc.)
  • Physical Properties
  • Tangential Load Test
  • Light Test to Ensure Complete Sealing
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