Shudder occasionally occurs in the lock-up clutch of automatic transmissions when the frictional characteristics of the lock-up clutch have a negative slope with respect to the relative slip velocity. This study evaluates the effect of a dynamic absorber on reducing shudder in an automatic transmission powertrain. The automatic transmission is modeled as a linear multi-degree-of-freedom system using Lagrange’s equation of motion. The optimal dynamic absorber characteristics for suppression of shudder are calculated. The experimental results reveal the optimized dynamic absorber can completely suppress shudder. Engine forced vibration analysis shows that the dynamic absorber can reduce vibration without any detrimental effects.
Image recognition of vehicles is still difficult for practical use under various actual environments. Recently
machine learning algorithm utilizing general feature amount have been often adopted. However, they utilize only a part of information obtained from images. Also, it’s difficult for human to understand the classifier, so care for individual recognition errors is hard. And so, we propose a method to design feature amounts hierarchically structuralized human’s empirical knowledge and adjust them by machine learning. Applying this method to images in actual environment, they were evaluated. As result of the experiments, 90% or more of recognition rate was achieved.
Aluminum titanate (AT)-based Diesel Particulate Filter (DPF) with hexagonal cell geometry has previously been presented as a promising media showing extremely lower pressure drop, coming from its specific hexagonal channels of DPF. In addition these AT characteristics, the investigation on an engine bench verified that AT filter with the hexagonal cell structure exhibited different combustion behavior from the one with the standard cell structure. To understand this behavior, direct observation inside the filter on its microscopic scale was carried out. It was found that the hexagonal channels induced multiple steps on particulate matter accumulation.
The design methodology for a new de-NOx system “DiAir” has been developed in this study. Based on the
NOx reduction mechanism, the amplitude of hydrocarbon (HC) concentration and the uniformity of exhaust gas and HC at inlet of the catalyst have been derived as the key factors to achieve high de-NOx performance. The improvement method of de-NOx performance in exhaust layouts for various vehicles has been clarified with improving the shape of the exhaust pipe and the configuration of the injector on engine test and CFD analysis.