Search Results

The effects of engine and after-treatment control conditions on emissions fluctuation were evaluated and the technical idea for improving the repeatability in tailpipe emission measurement from DISI vehicles was provided. To improve measurement repeatability, low emissions analyzers with dilution air refining system were employed for this research. In addition, a new device that enabled monitoring of signals from the Engine Control Unit (ECU) was developed. A novel approach using these devices was applied to DISI gasoline engine vehicles equipped with de-NOx catalyst to clarify emission characteristics in the Japanese 10.15 test cycle emission tests. Through the tests, it is found that NOx emissions most correlated with the temperature at the de-NOx catalyst. CO and HC reaching the de-NOx catalyst played an important role in the temperature increase of de-NOx catalyst by exothermic reactions.

This study describes the ignition of methanol spray formed by an ultrasonic atomizer under sub-zero conditions and the design of the methanol combustor as a H2+CO generator, based on partial oxidation reaction, for cold starting methanol engines. The methanol spray formed by the ultrasonic atomizer was observed to be ignited using a conventional ignition system even at sub-zero temperatures. Analysis of the spray characteristics showed that this successful ignition was attributed to the high amount of methanol vapor generated, which results from the fine spray and low momentum. The combustor using the ultrasonic atomizer was designed and tested. The combustor produced gaseous starting fuel (H2+CO) satisfactorily by using an adequate air register.

This paper describes the results of tests for diesel smoke reduction by gasoline fumigation using an ultrasonic atomizer, developed by TONEN Corporation. The spray of this ultrasonic atomizer is characterized by fine droplets of uniform size and low penetration. This means that the spray can be easily influenced by ambient air and delivered effectively to the cylinders. Based on these characteristics we proposed to reduce diesel smoke by fumigation, injection of fuel into the intake manifold. Gasoline was chosen as the fumigation fuel due to its ease of evaporation and easy handling. The fumigation tests were conducted on an engine running at full load producing dense smoke emissions. A commercial four cylinder diesel engine fitted with an ultrasonic atomizer to its intake manifold produced 50% smoke reduction at 15% fumigation ratio and approximately 70% smoke reduction at 30% fumigation ratio. However, other emissions, especially HC and CO, increased significantly.