Evaluating the Real-World NOx Emission from a China VI Heavy-Duty Diesel Vehicle

Abstract

The manufacturers of China VI heavy-duty vehicles were required to conduct in-service conformity (ISC) tests by using a portable emissions measurement system (PEMS). The moving averaging window (MAW) method was used to evaluate the NOx emission required by the China VI emission standard. This paper presented the results of four PEMS tests of a China VI (step B) N3 category vehicle. Our analyses revealed that the real NOx emission of the test route was much higher than the result evaluated by the MAW method. We also found the data produced during the urban section of a PEMS test was completely excluded from the evaluation based on the current required boundary conditions. Therefore, in order to ensure the objectivity of the evaluation, this paper proposed three different evaluation methods. Method 1 merely set the power threshold as 10% for valid MAWs; Method 2 reclassified the MAWs into “Urban MAWs”, “Rural MAWs” and “Motorway MAWs” according to the vehicle speed. Method 3 reclassified the MAWs into “Hot MAWs” and “Cold MAWs” according to engine coolant temperature. The NOx emission evaluation results for Method 1 were not satisfactory, but those for Method 2 and Method 3 were close to the real NOx emission, the errors were all within ±10%.

Analysis of Emissions and Fuel Consumption in Freight Transport

“…This resulted in a relatively low temperature of the exhaust gas, as a result of which the SCR system could not efficiently reduce the generated NO x . Similar conclusions were drawn by Li and Lü [23] whose RDE tests also confirmed the highest emission of nitrogen oxides during a city drive. As opposed to NO x , the emission of hydrocarbons had a different trend.…”

“…One of the problems of the powertrain technology in heavy-duty vehicles is the increased emission of particulate matter and nitrogen oxides. Many works have been devoted to the determination of the actual emission of NO x or the efficiency of selective catalytic reduction systems (SCR) [23][24][25]. Merkisz, Fuć et al [26] have tested under actual operating conditions two heavy-duty vehicles of different specific power output indexes.…”

Study on Emission Characteristics and Emission Reduction Effect for Construction Machinery under Actual Operating Conditions Using a Portable Emission Measurement System (Pems)

“…It was verified that the drift of each module during the experiment achieved the standard requirements. The emission rate of pollutant mass per second under actual operating conditions was obtained by using the experimental data through Formulas (1)–(5) [ 7 , 8 ]. where is the contaminant wet base concentration, the unit is ppm, or volume percentage; is the dry concentration of pollutants, in ppm, or volume percentage; is the dry and wet basis correction factor.…”

“…Since the emission standards of construction machinery lag behind the emission standards of on-road vehicles [ 6 ], the emission limit requirements of construction machinery are relatively low. The NO x emission limit of the sixth-stage vehicle test for heavy-duty diesel vehicles is 690 mg/kWh [ 7 ], and the fourth-stage NO x emission limit for non-road mobile machinery diesel engines is 0.67–3.5 g/kWh in Beijing [ 8 ]. Controlling the pollutant emission of construction machinery will be a significant project to reduce the emission of mobile sources in the future [ 7 , 8 ].…”

“…The NO x emission limit of the sixth-stage vehicle test for heavy-duty diesel vehicles is 690 mg/kWh [ 7 ], and the fourth-stage NO x emission limit for non-road mobile machinery diesel engines is 0.67–3.5 g/kWh in Beijing [ 8 ]. Controlling the pollutant emission of construction machinery will be a significant project to reduce the emission of mobile sources in the future [ 7 , 8 ].…”