Search

In this paper, a model for a prediction of conducted emission from vehicular PMSM-drive braking system is presented. The proposed model is based on the high-frequency circuit model combined with EM simulation. The parameter for high-frequency circuit modeling is derived from the measurement as well as 3D EM simulation based on FEM. To establish meaningful high-frequency parameters, the lumped parameters concerning the three-phase motor coil, motor busbar, heatsink, LISN, harness wire, meshed strap wire, and the passive-EMI filters including parasitics are either electromagnetically simulated or directly measured through an impedance analyzer. The distributed parameters of the PCB’s, connector, and motor housing are calculated via the 3D EM simulation. Eventually, the presented high-frequency parameters were integrated with PWM inverter circuit for the system-level analysis, and the model was verified through the correlation between the measurement and simulation with the EMI filters installed in the system. Moreover, the EMI characteristics with/without particular noise propagation path were analyzed in the model. The calculated conducted emission of the proposed model showed a very good agreement with the experimental data, which proves the validness of the proposed model.

The Homogeneous Charge Compression Ignition (HCCI) engine has attracted much interest because it can simultaneously achieve high efficiency and low emissions. However, the ignition timing is difficult to control because this engine has no physical ignition mechanism. In addition, combustion proceeds very rapidly because the premixed mixture ignites simultaneously at multiple locations in the cylinder, making it difficult to increase the operating load. In this study, an HCCI engine was operated using blended test fuels comprised of dimethyl ether (DME) and methane, each of which have different ignition characteristics. The effects of mixing ratios and absolute quantities of the two types of fuel on the ignition timing and rapidity of combustion were investigated. Cool flame reaction behavior, which significantly influences the ignition, was also analyzed in detail on the basis of in-cylinder spectroscopic measurements. The experimental results revealed that within the range of the experimental conditions used in this study, the quantity of DME supplied substantially influenced the ignition timing, whereas there was little observed effect from the quantity of methane supplied. Spectroscopic measurements of the behavior of a substance corresponding to HCHO also indicated that the quantity of DME supplied significantly influenced the cool flame behavior. However, the rapidity of combustion could not be controlled even by varying the mixing ratios of DME and methane. It was made clear that changes in the ignition timing substantially influence the rapidity of combustion.