| 摘要 |
PURPOSE:To measure the air-fuel ratio accurately and speedily by a simply constructed instrument, by carrying out an analog operation in a predetermined manner on the basis of the detection of carbon monoxide content, carbon dioxide content and hydrocarbon content in exhaust gas. CONSTITUTION:Carbon dioxide content, carbon monoxide content and methane gas-converted hydrocarbon content in exhaust gas are detected by nondispersion infrared analyzers 1f, 1'f and a flame ionization analyzer 2c. Analog voltage CO2, CO, THC corresponding to these detected value is adjusted to difference in detecting response speeds through filters 3... having large time constants as compared with the response times of the analyzers 1f, 1'f, 2c. The result signals are applied to an analog computing element AO through buffer amplifiers 4.... When the carbonization ratio m/n of fuel CnHm is 1.85, an analog operation in accordance with the formula I is carried out by operational amplifiers 5-7 connected via parallel- connected semifixed resistors R1, R2 and R<3>, R4; R5, R6; R7, dividers 8, 9 and adders 11, 12, etc. Therefore, the air-fuel ratio AFR can be measured accurately and speedily by a simply constructed instrument without conducting A/D conversion and hand-calculation. An operation in accordance with the formula II also permits the measurement of the air-fuel ratio at substantially the same accuracy. |
