Based on Lambert-Beer absorption law

a new dual gas infrared（ IR） sensor is designed with the principle of non-spectroscopic detection technology.IR sensor can detect CO2 and CH4.Design of reflective gas chamber with good stability and high sensitivity are put forward.In order to realize miniature design of sensor reasonable layout of IR light source and IR detectors in IR gas chamber location is carried out.The test results show that the largest measurement error of IR sensor with reflective gas chamber is only ± 0.05 %

when gas volume fraction of CH4 and CO2 at lower range.