Heavy-Duty Engines-Conformity Testing based on PEMS - Lessons Learned from the European Pilot Program

摘要

The European emissions legislation requires to check the conformity of heavy-duty engines with the applicable emissions certification standards during the normal life of those engines: these are the “In Service Conformity” (ISC) requirements.udIt was considered impractical and expensive to adopt an in-service conformity (ISC) checking scheme for heavy-duty vehicles, which require removal of engines from vehicles to test pollutant emissions against legislative limits. Therefore, it has been proposed to develop a protocol for in-service conformity checking of heavy-duty vehicles based on the use of Portable Emission Measurement Systems (PEMS).udThe European Commission through DG ENTR in co-operation with DG JRC launched in January 2004 a co-operative research programme to study the feasibility of PEMS in view of their application in Europe for In-Service Conformity of heavy-duty engines. The technical and experimental activities were started in August 2004 to study the feasibility of PEMS systems and to study their potential application for on-road measurements on heavy-duty vehicles.The main objectives of the above project had been defined as follows:ud-To assess and validate the application and performance of portable instrumentation relative to each other, and in comparison with alternative options for ISC testing;ud-To define a test protocol for the use of portable instrumentation within the ISC of heavy-duty vehicles;ud-To assess on-road data evaluation methods such as the US ‘Not To Exceed’ (NTE) approach and possibly to develop a simplified ones;ud-To address the need of the European industry, authorities and test houses to go through a learning process with on-vehicle emissions testing.ududThe main objective of the present document is to report on:uda. The evaluation of the test protocol, i.e. to judge whether the mandatory data and its quality were appropriate for the final evaluation (Sudb. The analysis conducted to evaluate the potential of the different data evaluation (Pass/Fail) methods for ISC and in particular their ability to use on-road PEMS emissions data. The candidate methods were categorized into two families:ud-The "control-area / data reduction methods" (Chapter 4) that use only a part of the data, depending whether the operation points considered are part of a control area and belong to a sequence of consecutive points within this control area. The US-NTE (Not To Exceed) method - already established as an official tool in the United States - falls into this category but variations of the methods could be envisaged (with another control area for instance).ud-The "averaging window methods" (Chapter 4.3) that use all the operation data.udThe main objective of task b. was to answer the following question: “Once the data has been collected correctly, what is the most appropriate method to analyze the test data measured with PEMS and to judge whether the engine is in conformity with the applicable emissions limits?”