Study of an Inspection and Maintenance System for Petrol and LPG Vehicles in Hong Kong Using a Combined Remote Sensing and Chassis Dynamometer System  

Project Title: Study of an Inspection and Maintenance System for Petrol and LPG Vehicles in Hong Kong Using a Combined Remote Sensing and Chassis Dynamometer System

Applicant: The Hong Kong Polytechnic University

Project Proponent: The Hong Kong Polytechnic University (Dr. CHEUNG Chun-shun)

Total Approved Grant: $429,095.76

Duration: September 2002 - August 2003

Project Status/Remarks: On-going

Scope:

The project is expected to last 10 months. The project aims to develop an inspection and maintenance system involving a remote sensing system and a chassis dynamometer in identifying high emitting petrol and LPG vehicles in Hong Kong. Identification of high emitters and having them repaired could help reduce the level of air pollution in Hong Kong. The PI plans to set up the remote sensing system at the PolyU and the chassis dynamometer at the HKIVE(LWL). Tests will be conducted on 10 petrol vehicles and five LPG taxis on different loaded test cycles. Suitable test procedures will then be developed for application to the Hong Kong situation. It is noted that the remote sensing system costing more than $1.2 million is already owned by the PolyU, while the chassis dynamometer costing $0.6 million will be donated by the manufacturer. The loaded mode test facilities will also provide opportunities for training practicing professionals and students in areas of motor vehicle emissions and control.

Summary of the Findings/Outcomes :

In this project, the exhaust emissions of 15 vehicles, including 9 petrol vehicles and 6 LPG vehicles, were measured. The exhaust emissions were measured with (a) a remote sensing system for instantaneous on-road vehicle emissions, (b) an exhaust gas analyzer for the no-load low idle and high idle tests; and (c) a chassis dynamometer for the loaded tests. The loaded test cycles include the TUV, the Modem IM, the Euro 195 and the IG 240. The following results are obtained:

  1. The remote sensing system can be applied to measure the exhaust emissions from motor vehicles, including both petrol and LPG fueled vehicles. The remote sensing result depends on the speed and the operation mode of the vehicle. Hence, the result cannot be used for direct judgment of the emission level of a vehicle.
  2. The loaded test cycles provide equal operation conditions for judging the emissions from motor vehicles. The results will be repeatable if the vehicle is sufficiently warmed up. However, the results vary from one test cycle to another.
  3. A comparison of the passing rate of the vehicles tested on the loaded and unloaded methods shows that the unloaded tests tend to overestimate the passing rate by a large margin.
  4. Both the TUV and Euro 195 are suitable test cycles for application in Hong Kong. The Euro 195 is preferred for simulating urban driving.