Spark ignition natural gas engines—A review

Experimental study on combustion characteristics of a spark-ignition engine fueled with natural gas–hydrogen blends combining with EGR

Combustion characteristics of a direct-injection engine fueled with natural gas–hydrogen blends under different ignition timings

This paper uncovers some of the misconceptions associated with the usage of producer gas, a lower calorific gas as a reciprocating engine fuel This paper particularly addresses the use of producer gas in reciprocating engines at high compression ratio (17 : 1), which hitherto had been restricted to lower compression ratio (up to 12 : 1) This restriction in compression ratio has been mainly attributed to the auto-ignition tendency of the fuel, which appears to be simply a matter of presumption rather than fact The current work clearly indicates the breakdown of this compression ratio barrier and it is shown that the engine runs smoothly at compression ratio of 17 : 1 without any tendency of auto-ignition Experiments have been conducted on multi-cylinder spark ignition engine modified from a production diesel engine at varying compression ratios from 115 : 1 to 17 : 1 by retaining the combustion chamber design As expected, working at a higher compression ratio turned out to be more efficient and also yielded higher brake power A maximum brake power of 175 kWe was obtained at an overall efficiency of 21% at the highest compression ratio The maximum de-rating of power in gas mode was 16% as compared to the normal diesel mode of operation at comparable compression ratio, whereas, the overall efficiency declined by 325% A careful analysis of energy balance revealed excess energy loss to the coolant due to the existing combustion chamber design Addressing the combustion chamber design for producer gas fuel should form a part of future work in improving the overall efficiency

Biomass derived producer gas as a reciprocating engine fuel—an experimental analysis

Investigation of combustion characteristics and emissions in a spark-ignition engine fuelled with natural gas–hydrogen blends

A 4 litre displacement, six cylinder, fuel injected petrol engine was modified to natural gas (NG) fuelling. Experimental investigation was carried out with various mixture controls and compression ratios over a wide range of operating conditions. As a strategy for combustion chamber shape modification, the compression ratio was raised with simultaneous enhancement of in-cylinder turbulence through squish motion. A fast burning chamber for the combustion of lean mixtures of natural gas and air was developed. Brake thermal efficiency in excess of 40 per cent and brake torque in excess of the peak base torque with petrol were achieved. The research provides the foundation for the implementation of NG cars that will emit only about 65 per cent of the carbon dioxide (CO2) of their petrol engine counterparts, with the prospect of extending the limited range of NG cars by up to one-third and producing low hydrocarbon (HC) and nitrogen oxide (NOx) emissions.

H C Watson

Papers

Development of a natural gas spark ignition engine for optimum performance