Lean Burn Natural Gas Operation vs. Stoichiometric Operation with EGR and a Three Way Catalyst

摘要: Exhaust emissions from lean burn natural gas engines may not always be as low the potential permits, especially with open-loop lambda control. These can produce much higher than a comparable diesel engine without exhaust aftertreatment. Even if has closed-loop control, are often unacceptably high for future emission regulations. A three-way catalyst is, today, best way to reduce hazardous emissions. The drawback is that operate stoichiometric mixture and this leads to; heat losses, pumping work at medium loads, thermal stress on knock tendency (requiring lower compression ratio, thus brake efficiency). One these drawbacks dilute EGR. This paper compares operation conditions diluted EGR, using catalyst. results show nitric oxides (NOdx) hydrocarbon (HC) several orders of magnitude operation. Higher loads achieved, efficiency optimized NOdx production. fast burning (high turbulence) combustion chamber used allow amounts dilution. (Less)