甲醇发动机甲醛排放测量不确定度评定
曹文明1，2，石来华1，2，康见见1，刘冰1，刘波1，吴滴1
1.招商局检测车辆技术研究院有限公司，重庆 400030；2.招商局检测车辆技术(合肥)有限公司，安徽 合肥 230000
摘要：为准确测量甲醛排放的不确定度，从人员操作、分析仪器、标准气体、标准溶液、试验标准循环、试验环境条件等方面分析影响重型甲醇发动机甲醛排放不确定度的测量因素，建立甲醛比排放数学模型，采用冷态全球统一瞬态循环（world harmonized transient cycle，WHTC）台架试验计算甲醛排放的相对标准不确定度。结果表明：甲醛比排放不确定度与重复测量、甲醛质量浓度、稀释因数、排气稀释后总体积、实际循环功的相对标准不确定度有关，其中稀释因数的影响较大；冷态WHTC试验平均甲醛比排放为41.6 mg/（kW·h），甲醛排放测量标准不确定度为1.29 mg/（kW·h），扩展不确定度为2.58 mg/（kW·h）。
关键词：甲醇发动机；甲醛排放；非常规污染物；不确定度
Uncertainty evaluation of formaldehyde emission measurement frommethanol engine
CAO Wenming1,2, SHI Laihua1,2, KANG Jianjian1, LIU Bing1, LIU Bo1, WU Di1
1. China Merchants Testing Vehicle Technology Research Institute Co., Ltd., Chongqing 400030, China;
2. China Merchants Testing Vehicle Technology(Hefei) Co., Ltd., Hefei 230000, China
Abstract: To accurately measure the uncertainty of formaldehyde emission, factors affecting the uncertainty of formaldehyde emission measurement from heavy-duty methanol engines are analyzed from various aspects, such as man, machine, material, method, and environment. A mathematical model of formaldehyde emission is established, and the relative standard uncertainty of formaldehyde emission is calculated using the world harmonized transient cycle (WHTC) test bench. The results show that the uncertainty of formaldehyde emission is related to the repeatability of measurement, the relative standard uncertainty of formaldehyde mass concentration dilution factor, total volume after exhaust dilution, and the relative standard uncertainty of actual cycle work. Among them, the dilution factor had a greater impact. The average formalhyde emission of the cold WHTC test is 41.6 mg/ (kW·h), and the standard uncertainty of formaldehyde emission measurement is 1.29 mg/ (kW·h), with an expanded uncertainty of 2.58 mg/ (kW·h). This research can provide a technical reference improving the accuracy and reproducibility of emission measurement of unconventional pollutants such as methanol and formaldehyde.
Keywords: methanol engine; formalhyde emission; unconventional pollutant; uncertainty
