This paper describes a survey of carbon monoxide (CO) and hydrocarbon (HC) emissions from a sample of 600 cars. The aim was to access the influence of the vehicle age distribution and time from the last inspection on emission levels. The survey was conducted under two conditions: idle and "load" engine modes (the last was 3000 rpm). The variation of CO and HC emissions with vehicle age (mileage) time elapsed since the last annual test, and engine capacity were revealed. The results were analyzed for both test conditions. Appropriate functions relating emission levels with the vehicle parameters were obtained. A strong vehicle age influence on emission levels was observed. There was no correlation of emission levels with time elapsed since the last test. Recommendations are presented for using the differentiated approach for various age groups of vehicles in maintenance and inspection programmes. (A)
Samenvatting