Catalyst Conversion Rates Measurement on Engine Fueled with Compressed Natural Gas (CNG) Using Different Operating Temperatures

Dariusz Szpica,Marcin Dziewiątkowski

doi:10.5755/j02.mech.30164

Abstract

Further restrictions on the use of compression-ignition engines in transportation are prompting the search for adaptations to run on other fuels. One of the most popular alternative fuels is Compressed Natural Gas (CNG), which due to its low carbon content can be competitive with classical fuels. This paper presents the results of testing a Cummins 6BT compression ignition engine that has undergone numerous modifications to convert to CNG power. The sequential gas injection system and the ignition system were installed in this engine. The compression ratio was also lowered from 16.5 to 11.5 by replacing the pistons. Tests conducted on an engine dynamometer were to show the differences in emission and conversion in the catalyst of hydrocarbons contained in the exhaust gases. Two structurally different catalysts operating at different exhaust temperatures (400 and 500)±2.5°C were used. The catalyst operating at 500±2.5°C showed a 23.5% higher conversion rate than the catalyst operating at a lower temperature in the range of the speed range tested. Also the external indicators, such as power and torque for the case of higher operating temperature took values over 70% higher. The research is one of the stages of a comprehensive assessment of the possibility of adaptation of compression ignition engines to CNG-only fueling.

Highlights

There is a plan in transport legislations to reach CO2 emission reduction 15% until 2025 and 37,5% until 2030 [1]
Attempts to meet increasingly stringent general standards related to GHGs [2] will form the basis for shaping the most recent Euro 7 emission [3]. This will most likely lead to the exclusion of the use of internal combustion engines used in classical transport as a single source of vehicle propulsion
Further work on regulatory characteristics in areas not yet in the spectrum is indicated. Based on this assumption and taking into account achievements of other researchers, an attempt was made to assess the degree of HC conversion in catalytic converters of various designs responsible for cleaning engine exhaust gases used for Compressed Natural Gas (CNG) fueling at fixed exhaust gas temperatures and variable engine rotational speed

Summary

Introduction

There is a plan in transport legislations to reach CO2 emission reduction 15% until 2025 and 37,5% until 2030 [1]. Attempts to meet increasingly stringent general standards related to GHGs [2] will form the basis for shaping the most recent Euro 7 emission [3]. This will most likely lead to the exclusion of the use of internal combustion engines used in classical transport as a single source of vehicle propulsion. This trend will force down transportation to switch drive train systems to hybrid types [4, 5] and electric drives [6], or to use H2 vehicles [7]. One way to seek a solution to the emissions problem may be to use multiple fuels [10, 11], or fuels with lower carbon content, in engines [9, 12]

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