Kiyohiko Oishi

The Effects of ‘Inclination Angle of Swirl Axis’ on Turbulence Characteristics in a 4-Valve Lean-Burn Engine with SCV

It has been demonstrated that the in-cylinder turbulence of a 4 valve engine with a swirl control valve (SCV) is enhanced by inclined swirl. This paper examines the effects on turbulence of varying swirl inclination angle defied as the inverse tangent of the vertical component of total angular momentum divided by the horizontal component. Experiments were conducted on a 4-valve single cylinder engine with SCV using a backward-scatter LDV and BSA (Bust Spectrum Analyzer). The results show that although total angular momentum is greatest with horizontal swirl, turbulence intensity measured in the center of the combustion chamber attains a peak value when the swirl inclination angle is between 30 and 45 degrees from the cylinder axis under the same flow rate.

Regenration Process of Ceramic Foam Diesel-Particulate Traps

Periodic regeneration of the diesel particulate trap is essential to maintain the collection efficiency and exhaust gas back pressure at acceptable levels. The objectives of this study are to describe the phenomenology of ceramic foam filter regeneration process and to present its mathematical model. Further simulation study is carried out to estimate the effects of various factors including fuel additive on the ignition and the filter bed temperature and to investigate conditions of excessive temperature which could result in filter destruction. The model is based on the assumption that the regeneration process is composed of two steps. The first step is the additional heat supply from the external energy source, and the second step is the spontaneous combustion propagation. The results from the analytical model agreed very well with the experimental results. Additional energy is required above normal engine operating conditions to initiate the incineration under lower exhaust gas temperature. Regeneration must be carried out within a narrow range of particulate loading to avoid the melting of the filter material. The effects of fuel additives have been estimated by using the mathematical simulation.