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thermal conductivity figures. Linersmade of suitable aluminiummaterials can, according to thepresent state of the art, only becast in by high-pressure diecasting because they have to relyon extremely short solidificationtimes due to the melting-throughrisk. However, the outer-face areafusion of aluminium liners withthe aluminium casting is notsatisfactory. A mechanical clampingin conjunction with BMI-castiron liners (BMI = bimetal interlock)is possible.Cast-in liners have residual stresseswhich are difficult to control. Thesituation is rendered even moredifficult by the casting tolerancesand deformation. Developmentefforts which should not be underestimatedare therefore needed tocontrol multifactor-conditionedcylinder distortion problems withstatistically anticipated potentialfunctional disadvantages, especiallyin long-term operation.■ LOKASIL ® TechnologyMonolithic and/or quasi-monolithicconditions largely avoid thedescribed disadvantages. In theearly 1990’s KS ATAG started thedevelopment of the local compositematerial solution LOKASIL ® as thebetter alternative to the liner. Thegapless insertion of the compositematerial in its surroundings isgenerated by the infiltration ofhighly porous hollow cylindricalbodies (preforms) made of siliconwith a base alloy for casting underhigh pressure as an artificialcounterpart to the metallurgicallyproduced ALUSIL ® (registeredtrademark of KS ATAG, hypereutecticalloy AlSi17Cu4Mg). The infiltrationpresupposes the squeezecasting or real-time controlledhigh-pressure die casting processwith solid steel dies.With these casting processes, it isnot possible to cast ALUSIL ® withsatisfactory process reliability. Thatis why KS ATAG has developedan equivalent concept with localsilicon enrichment for highpressuredie casting processes:LOKASIL ® . The holistic approachis apparent in a new honingprocess, worked out in line withthe development of LOKASIL ® andtested for mass production, whichincludes the mechanical “uncovering”of the silicon grains. Thisprocess can replace the chemicaletching process and produces anexcellent, tribologically optimisedsurface. Only monolithic andquasi-monolithic concepts withtheir fundamental advantages(see for example the productinformation sheet “Low-pressureDie Cast Engine Blocks made ofAluminium”) additionally supportunproblematically the frequentsrequest for cylinder units of maximumcompactness (minimumland width between cylinders =minimum cylinder distance). WithPorsche as pilot customer, theSilicon preformseries introduction of LOKASIL ®engine blocks was successfullylaunched with the Boxster and thenew water-cooled “911” nowcalled Carrera (identical engineblocks in two bore/swept-volumevariants). The LOKASIL ® II variantof the LOKASIL ® material family isapplied in this case. If, due to minimumdimensions between thecylinders and/or elevated componenttemperatures, demands onstrength are higher, the aluminiumoxide fibre-reinforcedLOKASIL ® I variant is available.Further LOKASIL ® variants withspecific application targets are inthe development stage.LOKASIL ® cylinder bore surface(local silicon enrichment)