The effects of nozzle hole diameter on combustion and exhaust emissions were investigated using a single-cylinder DI diesel engine. ( 1 ) Exhaust NOx and combustion period depend only on injection pressure and not on nozzle hole diameter, because with a small-hole- dia. nozzle the effect of reduced mean injection rate is canceled out by the effect of promoted mixture formation and combustion. (2) With decreasing injection pressure, smoke sharply increases with a large hole-dia. nozzle but does not increase with small hole diameter of less than 0.20 mm. The decrease of injection pressure reduces NOx emission. ( 3 ) The effect of suppressing the increase of smoke with a small hole-dia. nozzle is considered to be caused mainly by the rapid temperature rise over about 1 800°C in the fuel- rich region near the spray in flame. ( 4 ) With the conversion of a deep bowl combustion chamber to a shallow-dish one, smoke increases as injection pressure decreases, in spite of the use of a small-hole-dia. nozzle, due to the reduction of mixing effect.
|Number of pages||9|
|Journal||Transactions of the Japan Society of Mechanical Engineers Series B|
|Publication status||Published - 1994|
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanical Engineering