Effect of Hydrogen in CNG on Small Engine Performance and Emissions 2011-24-0202

Three-wheelers have a long history in Europe and Asia as extremely durable and reliable passenger and delivery vehicles. There are a number of reasons that have resulted into the proliferation of the 3-wheelers in developing countries especially in South Asian countries. 3-wheelers are quite economical in terms of manufacturing and maintenance. They have also earned huge popularity due to their easy maneuvering capabilities. The inherent engine design of 3-wheeler with conventional fuels have recognized for lower fuel economy and higher emissions. Concerns about energy security, air quality and need for sustainable economic growth are making it imperative that all nations, especially developing countries, begin making an accelerated transition from fossil fuels to clean energy alternatives. South Asian countries have already done a remarkable job of converting a large number of three-wheelers and buses to compressed natural gas (CNG), and in India there is an on-going effort to extend this transition to hydrogen blended CNG (HCNG). Hydrogen is being added in CNG as an additive for further improving its combustion efficiency. Optimized hydrogen enriched natural gas (HCNG) engine has potential in reducing of harmful emission and greenhouse gases.

This paper highlights engine performance, regulated and non-regulated emissions using CNG and 18% HCNG blend (v/v) with different measures in a CNG three-wheeler was tested on chassis dynamometer for performance and emissions. Ignition timing of the engine was optimized for better performance. Results indicated that significant reduction in CO and HC with penalty in increase NOx emission with use of HCNG fuel. To control NOx emissions, simple mechanism of EGR system was introduced. Although hydrogen enriched fuel reduces harmful emissions significantly, non-regulated emissions were observed with HCNG fuel. Growing concern over non-regulated emissions, it is imperative to estimate non-regulated emission for assessing overall emission advantages of HCNG fuel. Non-regulated emission also measured and reported for overall emission benefits with use of HCNG fuel.