Effect of Compression Ratio on the Performance of a Constant Speed Spark Ignition Engine Operating on Raw Biogas

Santosh Kumar Hotta; Niranjan Sahoo; Kaustubha Mohanty; Pinakeswar Mahanta

Authors

Santosh Kumar Hotta Centre for Energy, Indian Institute of Technology Guwahati, Guwahati – 781 039, India
Niranjan Sahoo Dept. of Mech. Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, India
Kaustubha Mohanty Dept. of Chem. Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, India
Pinakeswar Mahanta Dept. of Mech. Engineering, Indian Institute of Technology Guwahati, Guwahati-781039, India

Keywords:

SI Engine, Biogas, Performance Analysis

Abstract

In the present investigation, experiments were conducted in a 4.4 kW, single cylinder, water cooled, constant speed, spark ignition (SI) engine fuelled with raw biogas. The engine was operated at four different compression ratios (10.52, 11.94, 13.96 and 15.29) and within a load range of 6 to 77%. The effect of load level on the performance and emission characteristic of the engine at different compression ratios are analysed and presented in this paper. The brake power producing capability of the engine corresponds to CR 15.29 was maximum and found to be 2.93 kW with 76.27% of brake load. With increasing CR the engine becomes more stable and operates with an appreciable deviation in speed. Irrespective of engine loading condition, the minimum HC and CO emissions were noticed at CR 15.29 and found to very between 23-144 ppm and 0.016-0.091 %, respectively. The maximum NOx emission was detected at CR 15.29 and was found to very between 27-240 ppm.