Abstract
The internal flow in a box type intake manifold of an in-line six cylinder diesel engine is investigated experimentally under steady state flow conditions. The optical diagnostics are performed through transparent glass windows fitted on the manifold wall. Measurements include qualitative flow pattern visualization by means of Tracer Laser Sheet (TLS) technique and quantitative velocity distribution by Laser Doppler Velocimetry (LDV). Experimental results show that three dimensional spiral flow is observed in this intake manifold, and it is also found that stagnant eddies which obstruct the inflow into the intake ports are generated.