Calculation method for NOx emissions in PEMS testing of heavy-duty diesel vehicles

By establishing a fuel consumption window method in the PEMS test of heavy-duty diesel vehicles and utilizing C-WTVC cycle and fuel consumption data, the problem of lack of vehicle reference torque and WHTC cycle work in OBD data is solved, enabling accurate calculation of NOx emissions and regulatory support for high-emission vehicles.

CN115655730BActive Publication Date: 2026-06-30CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD
View PDF 2 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD
Filing Date
2022-11-09
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

In existing technologies, NOx emissions cannot be directly calculated using OBD data in PEMS testing of heavy-duty diesel vehicles because of the lack of reference torque information and WHTC transient test cycle work, which makes it impossible to accurately determine the vehicle's emission status.

Method used

The nominal cycle average power of the vehicle is calculated based on the speed-time curve of the C-WTVC cycle. Combined with fuel consumption data, a fuel consumption window method is established to replace the power-based window method to calculate NOx specific emissions. The calculation includes steps such as fuel consumption window division, average specific power calculation and NOx specific emission calculation, utilizing information from existing OBD data streams.

Benefits of technology

It enables accurate calculation of NOx emissions from heavy-duty diesel vehicles using existing OBD data systems, supporting regulatory authorities in the precise supervision and screening of high-emission vehicles, with errors within acceptable limits.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN115655730B_ABST
    Figure CN115655730B_ABST
Patent Text Reader

Abstract

This invention discloses a method for calculating NOx emissions in PEMS testing of heavy-duty diesel vehicles, comprising: calculating cumulative fuel consumption in chronological order of testing time; defining a fuel consumption window as the cumulative fuel consumption reaching the nominal WHTC cycle fuel consumption; calculating the specific NOx emission of each window based on the NOx concentration in the exhaust, exhaust flow rate, and fuel consumption-power conversion coefficient; calculating the ratio of the average fuel consumption rate of the window to the nominal maximum fuel consumption rate as the average specific power of the window; defining a window whose average specific power is greater than 20% of the engine's maximum power as a valid window; filtering valid windows among all windows; sorting the specific NOx emission values ​​of the valid windows; comparing the specific NOx emission output at 90% of the positions with a preset limit to determine whether the vehicle meets the requirements. This invention can accurately reconstruct the specific emissions of a vehicle based on the PEMS power-based window method based on data items and information in the OBD data stream.
Need to check novelty before this filing date? Find Prior Art