Effect of compression ratio and spark timing on the power performance and combustion characteristics of an HCNG engine

Effects of compression ratio on performance and emissions of a modified diesel engine fueled by HCNG

“…As an example, the minimum values of 207, 210, 215 and 247 g/kWh are gotten at l ¼ 1.1, l ¼ 1.15, l ¼ 1.22 and l ¼ 1.27 fueled by CNG, HCNG5, HCNG10 and HCNG20 for 15 CR, respectively. The low flame speed and the poor lean-burn capacity of CNG led to CNG as favorable fuel at stoichiometric conditions [11]. In addition, due to high flame temperature and high flame speed of hydrogen, HCNG is considered to be the favorable fuel at lean mixtures [10,11,22].…”

“…The low flame speed and the poor lean-burn capacity of CNG led to CNG as favorable fuel at stoichiometric conditions [11]. In addition, due to high flame temperature and high flame speed of hydrogen, HCNG is considered to be the favorable fuel at lean mixtures [10,11,22]. It is observed there is an advance in BSFC with the increase of hydrogen fraction in natural gas for CR of 12.5 and 15.…”

“…Due to high flame temperature and high flame speed of hydrogen, the increase of the hydrogen fraction in HCNG led to increase the temperature of mixture and the residence time of air in the hot zone. So, NO X increased by addition of hydrogen to CNG [11].…”

“…The lean mixture or the decreasing CR results in a decrease in cylinder temperature and so BSFC values increase. The cylinder temperature and thermal efficiency are increased by adding hydrogen which has high flame temperature and high flame speed for low CR [10,11].…”

Performance and emissions of a modified small engine operated on producer gas

“…The engine torque of the diesel engine was always higher than that of the producer gas engine. Reduction of engine torque can be attributed to low energy density of producer gas which is a limitation of gaseous fuels, compared with liquid fuels [19]. Moreover, reduction of CR caused the engine torque to decrease.…”