METHOD OF DIAGNOSING CONDITION OF CYLINDER-PISTON GROUP OF INTERNAL COMBUSTION ENGINE Russian patent published in 2002 - IPC

FIELD: mechanical engineering; engine testing. SUBSTANCE: engine crankshaft is crankshaft is cranked using external source and communicating above-piston space in cylinder with atmosphere at compression stroke and isolating above-piston space from atmosphere at expansion stroke, and maximum first depression P_1m in above-piston space is measured at expansion stroke and technical condition of valve mechanism is judged by comparing P_1m with preliminarily set maximum depression P_Vmax for valve mechanism. At P_1m>P_Vmax technical condition of cylinder sleeve is determined by comparing P_1m with preliminarily set maximum depression for sleeve P_Smax and with nominal depression for sleeve P_Smax. At P_1m>P_Smax crankshaft is cranked additionally isolating above-piston space from atmosphere at expansion and compression strokes, maximum second depression is above-piston space is measured at expansion stroke and technical condition of compression rings is determined by comparing measured second depression P_2m with preliminarily set maximum depression for rings P_Rmax and nominal depression for rings P_Rnom At number of cylinders in engine more than one and at condition that in all cylinders P_1m>P_Smax and neither replacement nor repair of separate sleeves have been carried out in all cylinders, difference between two maximum measured values of P_1m in two different cylinders is determined, and by value of found difference, condition of oil control rings of cylinder having maximum value P_1m is determined. EFFECT: reduced labour input and provision of accurate determination of technical condition of valve mechanism, cylinder sleeves and piston rings. 2 cl, 1 dwg