SAE journal paper about LaVision´s innovative optical measurement technique for gas engine development now online!
Tuesday, 12. March 2019
Methane and Compressed Natural Gas (CNG), as gaseous fuels, offer new ways for low emission engine developments. As in-cylinder mixture formations are harder to control compared to liquid fuels, detailed information about these processes are essential for engine optimization.
At the SAE World Congress Experience 2018 two optical measurement techniques for time resolved Lambda-value analysis were presented. With the two dimensional LIF, a laser light sheet imaging technique, the mixture formation in one plane can be compared to the CFD simulation as shown in Figure 1.
Figure 1: Comparison of Lambda images between LIF imaging and CFD simulation.
Second the infrared technique of the ICOS-CNG system measures the Lambda-value locally at the tip of the spark plug. This is equipped with the necessary optics and no engine modifications are necessary when using this sensor probe. The detailed Lambda evolution in the engine cycle can be obtained as shown in Figure 2. In this example the simulated evolution is slightly retarded compared to the real one, measured by the two measurement techniques.
Figure 2: Lambda-value evolution measured by the infrared technique and compared to LIF measurements and simulation.