MAHLE 2010

Technical information Pistons Piston rings Cylinder liners/finned cylinders Assembly

Types

Cast solid skirt pistonsdistinguish themselves with a long operatinglife and economic viability for gasoline and die-sel engines. In these pistons, the pistoncrown, ring zone and skirt make a robust unit.Therefore the possibilities for use range from amodel engine to a large engine.

Forged solid skirt pistonshave increased strength due to the manufactur-ing process. This means that smaller wall cross-sections and lower piston weights are possible.These pistons are installed, above all, in mass-produced engines that are subject to heavyloads, and in engines for racing sports.

AUTOTHERMATIK-/HYDROTHERMATIK pistonsalso have cast steel strips, but they are notslotted and so they make a uniform body withgreater strength. They are preferred for instal-lation in gasoline and diesel engines for carsthat are subject to heavy loads.

Two-stroke pistonsare subject to strong mechanical and thermalloads due to the design principle of two-strokeengines. Special aluminium alloys are used soas to meet these requirements in the best pos-sible way.

ECOFORM pistons withpivoted side coreWeight optimised pistons for passenger car petrol engines. As a result of a specialcasting technology these pistons offer lowweight and high structural rigidity.

AUTOTHERMIK-/HYDROTHERMIK pistonshave cast steel strips and are slotted at thetransition from the ring area to the skirt area.These pistons run very smoothly and are pre-ferred for installation in car engines.

MAHLE 2010

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FERROTHERM pistonsconsist of a steel piston head and an alumin i-um piston skirt which have a moveable con-nection to each other via the piston pin. Dueto great strength and low wear and tear, it ispossible to achieve low exhaust emission val-ues for diesel engines that are subjected toparticularly high loads.

Ring carrier pistons with cooling galleryare used in situations in which particularly highoperating temperatures occur. In order toreduce the high temperatures which arecaused by the increased performance in thepiston crown and in the ring area, intensivecooling is done by circulating oil in the coolinggallery.

Ring carrier pistons with pin boss busheshave a ring carrier made of special cast ironwhich is cast into the piston. This providesprotection to the top ring groove from thewear and tear which diesel engines in partic-ular are subject to. In order to make it possibleto increase the loads to which the pin bosscan be subjected, this piston has pin bossbushes that are made of a special material.

Pistons with cooled ring carrierhave significantly improved heat dissipation atthe first ring slot. This is achieved with a combi-nation of ring carrier and cooling gallery, in whichthe two components are combined into onesystem in a special production process.

Ring carrier pistons with cooling gallery and crown reinforcementare used for highly loaded diesel engines. Foradditional protection and in order to avoid crak-king in the combustion chamber and the crown,these pistons have a special hard anodisedlayer (HA layer) on the piston crown.

MAHLE 2010

Technical terms

Technical information Pistons Piston rings Cylinder liners/finned cylinders Assembly

Pistons (dimensions)AA = Distance between bossesF = Top land heightGL = Total lengthKH = Compression heightM = Combustion chamber diameterMT = Combustion chamber depthMV = Combustion chamber offsetH = Dome heightVT = Valve recess depth

Types of semi-finished pistonF = Squeeze-cast pistonKB = FERROTHERM pistonL = Solid skirt pistonP = Forged pistonV = AUTO-/HYDROTHERMIK piston/

AUTO-/HYDROTHERMATIK piston

AK = Recess for oil cooling nozzleDRT = Double ring carrierKK = Cooling gallery, in some cases

with recessRT = Ring carrier

FERROSTAN = FERROSTAN-coatedHA = Hard anodisedC = Graphite coated

Piston pinsPin dimensions:Outer diameter of pin x total length

FB = Profiled pinNB = Pin boss bushingS = Shrink fit-/clamp type con rodT = Keystone con rod

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