Air Flow Visualization in a Multi-Point Injection Type Manifold

This paper has two purposes: the first is to study the air flow behavior in the MPI type engine manifold by means of flow visualization; the second purpose is the verification of the air flow characteristics described in SAE paper No.950066 (1)using the results of that paper. The tuft grid method was adopted for air visualization. The MPI type engine manifold used in this study (common chamber) has dimensions of 332 × 79 × 74mm. The amount of the tuft is 630 points. Two directions(yz and xz planes, respectively) of the tuft were instantaneously photographed at every 20 degrees of crank angle and the composed direction was calculated. The experimental conditions are 1) steady air flow, 2) transient flow, 3) the inlet pipe position and 4) ram pipe locations. The main experimental results are I) the horizontal location of the throttle valve is less than vertical for air flow loss, II) some swirls generates in the space of the induction passage way do not act in the common chamber at the transient condition, III) due to motion of the throttle valve various sizes of swirls were generated and IV) the correlation of relative rising rate for air flow and the air flow behavior were clarified.