Studies on air pollution owing to the automobile exhaust gases. The concentrations of C1-C6 hydrocarbons and some inorganic gases in the exhaust gases

Abstract

The exhaust gases of a passenger car during idling were analized by using the gas chromatography (Yanagimoto model 5DH, equipped with the flame ionization and the thermal conductivity detectors) to investigate the relation between the revolutions of the engine and the composition of exhaust gases. The car employed was DATSUN, model 1959, which had a 4 cycle engine (cylinder volume: 988ml) and had been driven 155, 000km. The measurement of the fuel consumption rate, air-fuel ratio, exhaust gas temperature, intake air volume, emission gas volume and the concentration of the individual components was performed at a constant revolutions (600 to 5, 000rpm).The results obtained were as follows:1) The fuel consumption rate at 600rpm was 227g/ps⋅hr and decreased with increasing revolutions. The volumetric efficiency of intake air-fuel mixtures was very low (31 to 53%) during idling. The air fuel ratio was 10.4% at 600rpm and the air rich state (the fuel lean state) was observed when rotation was over 2, 500rpm.2) The temperature of the gases emitted from the exit of the tail pipe was 60 to 80°C at 600 to 1, 500rpm. The temperature higher than 300°C was recorded at 4, 000rpm.3) At 600rpm CO2 content was found to be 2.1%. The maximum CO2 content (10.3%) was observed at 3, 000 to 4, 000rpm. The maximum concentration of CO (9.9%) was found at 600rpm and the concentration of CO was decreased with increasing revolutions (4.4% at 5, 000rpm).These results would suggest that the exhaust gases containing 10% CO would be discharged into the atmosphere when this car temporarily stopped at an intersection.4) In the exhaust gases, C1 to C6 hydrocarbons (25 kinds) were identified. 3, 645.p ppm as total was determined at 600rpm and 689.9ppm at 4, 000rpm. At 5, 000rpm, 842.2ppm as total was determined. The relatively large contents (5.5 to 23.7%) were found as methane, ethane, n-butane, i-butane, ethylene and propylene during idling.5) The composition of exhaust gases during idling was paraffin (62%), olefin (33%), diolefin (0.4%) and acetylene (5%), on an average.6) The ratio of the emitted hydrocarbons to supplied fuel was about 10% (w/w) at 600rpm and 3% at 4, 000rpm. The gross emission of the hydrocarbons per minute during idling was 1.79g/min at 600rpm and 0.94g/min at 3, 500rpm.