| 摘要 |
<p>PURPOSE:To detect air fuel ratio near an ignition plug before ignition timing with high accuracy. CONSTITUTION:A laser beam having the wave length for selectively absorbing gasoline is emitted from a laser sorce 12. After the laser beam is passed through a space in a combustion chamber 5 by a pair of optical elements 10, 11, it is conducted to a photoelectric transfer element 14. Here, the laser beam is absorbed according to the concentration of gasoline present in a gap between a pair of optical elements 10, 11 so that the brightness of a transmitting beam incident on the photoelectric transfer element 14 is changed and affected by pressure in the cylinder. Then, in a control unit 15, an air fuel ratio is calculated on the basis of the pressure in the cylinder detected by a pressure-in-cylinder sensor 7 and the output of the photoelectric transfer element 14.</p> |
