The Internal Combustion Optical Sensor (ICOS)-Temperature system from LaVision allows analysis of time-resolved in-cylinder gas temperature in an internal combustion engine. The minimally invasive sensor is available with a choice of in-cylinder probes. The system delivers crank angle resolved single cycle and cycle averaged gas temperature and water concentration curves over many consecutive cycles.
The high temporal resolution of the ICOS systems allows the analysis of in-cylinder temperatures during transient operation. The diagram shows the transient behaviour of the temperature during a tip-in (load change) operation for 15 engine cycles. The engine is coasting over the first 5 cycles. After this the accelerator pedal is pushed down resulting in a load step and transient firing behaviour over 7 cycles. The combustion process then stabilizes in the following cycles. The shown temperature profiles are averaged over 10 repeated tip-ins.
Optimizing engines under transient operation is becoming increasingly important to meet RDE requirements
The water concentration can be detected at different locations in the cylinder giving insight to the mixture formation process, especially when applying exhaust gas recirculation (EGR). The line-of-sight probe, located at the engine‘s liner, measures integrated across the cylinder and therefore reveals the average value. In contrast to that, the spark plug probe measures the water concentration locally. Water concentration measurements of three individual cycles with the spark plug probe and the line-of-sight probe clearly highlight local differences between these location.