Search Results

Compared with in-line 4-cylinder engines, V-6 engines show a slower rise in exhaust gas temperature, requiring a longer time for catalysts to become active, and they also emit higher levels of engine-out emissions. In this study, The combination of a new type of catalyst, and optimized ignition timing and air-fuel ratio control achieved quicker catalyst light-off. Additionally, engine-out emissions were substantially reduced by using a swirl control valve to strengthen in-cylinder gas flow, adopting electronically controlled exhaust gas recirculation (EGR), and reducing the crevice volume by decreasing the top land height of the pistons. A vehicle incorporating these emission reduction technologies reduced the emission level through the first phase of the Federal Test Procedure (FTP) by 60-70% compared with the Tier 1 vehicle.

A model of a timing belt analyzed by FEM (a general non-linear finite element program:ABAQUS) successfully confirmed the mechanism that generates belt cord stress. Analysis revealed a good correlation between the experimental and computed results of stress distribution of the belt cord. Through calculation, it was discovered that belts broke near the tooth root, which is the point of maximum stress of the cord.

A timing belt used for an automotive engine's camshaft consists of a facing fabric, elastoeric body and glass fibre cords. These materials show significant non-linear characteristics. Therefore, a model of the timing belt was analyzed using ABAQUS (: a general non-linear finite element program). As a result, the mechanism that generates the belt load distribution was successfully confirmed by calculation. It was found that the pitch difference existing between the timing belt and pulley, and belt tooth configuration both have a large affect on load distribution of toothed belts. This paper reports the development of an analytical model which shows the effects of pitch difference and pulley tooth configuration on belt contact pressure.

Some attempts at developments and analyses of oxygen sensors are presented with a review in this field. For oxygen concentration cell type zircornia sensors for stoichiometric A/F control, its mechanism is discussed and a unified explanation is proposed. For oxide semiconductor type oxygen sensors, TiO2, Nb2O5 and CeO2 sensors are described with an emphasis on a recently developed Nb2O5 thin film oxygen sensor. Several types of lean A/F sensors are also discussed. Of these sensors, oxygen sensors which utilize the electrochemical pumping action of a solid electrolyte are preferable.