增压稀燃天然气掺氢发动机排放特性

Emission Characteristic of Turbocharged Lean Burn HCNG Engine

为了研究20％掺氢比的增压稀燃天然气掺氢（HCNG）发动机的排放特性，通过对发动机进行了空燃比和点火提前角调整试验、ETC循环测试试验和加装氧化型催化器试验，获得了20％HCNG发动机的排放规律。CH4排放随着空燃比的增大先减少后增加；CO排放在高于理论空燃比后骤减；NOx排放随着空燃比的增大先增加后减少，在空燃比19～21左右达到最大值，1600～1800r／min时最低。CO、NOx随着点火提前角的增大而增加；CH4随着点火提前角的增大略有增加，并且点火提前角越大，对CH4排放的影响越小。加装催化器后，CO、CH4的转化效率均〉90％。试验结果表明：增压稀燃和氧化型催化器相结合是天然气掺氢发动机节能减排的有效方案。

In order to study emission characteristic of turbocharged lean burn HCNG engine with adding 20 % hydrogen, an experimental research on the influence of air fuel ratio, spark ignition timing and oxidation catalyst converter was conducted. The result shows that NOx emissions increase initially and then decrease as the air fuel ratio increases. The highest NOx emission value occurs at air fuel ratio of 19-21 while the lowest NOx emission value occurs at 1 600- 1 800 r/min engine speed. CO emissions suddenly decrease after air fuel ratio is less than stoichiometric value. With the increase of spark ignition advanced angle, CO and NOx emissions increase while CH4 emissions increase slightly. After installing the oxidation catalyst converter, CH4 and CO emissions are reduced by more than 90 percent. The result shows that turbocharged lean burn in combination with oxidation catalyst converter is an effective technical way for reducing the emission of HCNG engine.