Offprint from MTZ 06.2013 Springer Vieweg Springer Fachmedien Wiesbaden GmbH MEASUREMENT OF IN-CYLINDER MIXTURE FORMATION BY OPTICAL INDICATION

DE VELO PMENT SENS ORS Modern engine concepts are based on complex mixture formation and combustion processes with direct injection, exhaust gas recirculation and downsizing. Their successful optimisation as well as specific conditions such as cold start behaviour requires an extension of pressure indication by the addition of engine-relevant indication quantities. The sensor system presented in the following supplements the established pressure indication system by adding the optically measured in-cylinder characteristic quantities of fuel density, residual gas content and mixture temperature,...

MEASUREMENT OF IN-CYLINDER MIXTURE FORMATION BY OPTICAL INDICATION The company LaVision has developed an optical indication process that can be used to determine lambda, residual gas and temperature curves in the combustion chamber with high temporal resolution. The sensor system is able to provide crank angle-resolved, real-time measurements of the complete process of in-cylinder mixture formation over hundreds of single cycles. curves can be recorded simultaneously with the same sensor probe. From the measured CO2 concentrations in the cylinder, cycle-resolved internal EGR rates can be determined,...

INDICATED QUANTITY Data acquisition Crank angle-resolved multiple cycles Accuracy < 2 % < 2 % ± 20 K at 3 vol. % H2O Derived quantity X value Internal EGR - Sensor probes M12/M14 spark plug, M5 glow plug adapter, M5 indication bore hole, transmission probe Mixture preparation, stability of the combustion process Direct injection Cold start Load changes Ignition behaviour Cycle-resolved EGR rate : Validation Equal distribution over cylinder : Supercharging, EGR Valve timing : HCCI 0 Overview of systems -120 -60 0 Crank angle [°CA aTDC) 0 Non steady-state...

The example in Q shows a single cycle with simultaneous indication of the fuel density and residual gas density using a sensor probe integrated into a spark plug and measurement of the pressure curve at the same time through a separate indication bore hole. The measurement of the residual gas density in the cylinder allows the EGR rate, which is composed of the external and internal EGR rate, to be derived from a comparison of the curve before and after combustion. CO2, EGR RATES AND DERIVED QUANTITIES A uniform distribution of the EGR rate, an even residual gas mass in all cylinders combined...

Crank angle [°CA aTDC] ❻ Gas temperature curve of a gasoline engine, measured close to the spark gap cylinder cross-section are measured with an arrangement of transmission sensors. ❻ shows the temperature curve together with the indicated pressure in a gasoline engine. Temperature indication can be used to observe the influences of, for example, exhaust gas recirculation on the gas temperature during the compression phase in real time, thus making it possible to clearly classify the ensuing effects on the combustion process and ignition behaviour. Optical engine indication extends the established...