The work is a part of emission inventory of spark-ignition engines to be used as a basis for a future amendment of the Directive 97/68/EC.
The inventory covers seven different categories of engines – mainly small ones. They have been bought by the laboratory on the market without presenting the intention of the purchase to get as representative engines as possible.
The study is presenting emission levels for different technologies, the influence of deterioration and the influence of different test procedures. The study was designed to complete a similar emission inventory financed by the German UBA, presented in 1997.
Based on the study the following indications could be noticed:
- 29 engines were tested on test benches using test cycles as defined in ISO 8178 part 4.
- Power output, fuel consumption and emission of CO, HC, NOx and CO2 were measured. Particulate emission was measured only on diesel engines.
- 5 of the engines tested were diesel engines with a range of power output from 28 to 140 KW. This engine category 'a' represents all diesel engine technology available today.
- 6 spark ignition engines of a power range from 6.6 KW to 18.4 KW used in transportable generating sets were tested as category 'b'. All this engines are 4-stroke ones without any exhaust after-treatment.
- Also 3 engines fuelled with LPG applicable for fork lifts were tested, see engine category 'c'
- In category 'd + e' 9 Sl-engines of a power range from 2.1 KW to 14.9 KW were tested according to both test cycles G1 and G2. Except one all of this engines are 4-stroke ones.
- The small engines of handheld utility or lawn and garden equipment –power range 0.6 KW to 2.6 KW – were tested as engine category 'f'. Two of them are sophisticated 4-stroke engines with a sweep volume of 22 cm3 and 26 cm3.
- Finally all engines of category 'f' were undertaken an endurance run consisting of 600 test cycles over 100 h to show the alteration of exhaust emissions.