Changing emissions standards
Beginning with all heavy-duty truck engines manufactured on or after January 1, 2010, the U.S. Environmental Protection Agency issued new lowered NOx emissions standards. To meet these requirements, many heavy-duty engine OEMs, particularly those whose manufactured end products are found within Class 7 to Class 8 trucks, have implemented selective catalytic reduction (SCR).
SCR requires the periodic addition of a urea-based diesel exhaust fluid (DEF) to the heavy truck engine. The DEF is added to the exhaust stream in the presence of a catalyst. The interaction between the catalyst and fluid results in the chemical conversion of unwanted NOx compounds into more environmentally friendly water and nitrogen gas. To achieve optimized NOx emission reductions, automotive engineers must work to continuously fine-tune the delivery of the dosing agent to the engine exhaust.
Streamlining data acquisition processes
A leading Tier 1 supplier of emissions and ride control products wished to streamline their fleet vehicle data acquisition processes. The ideal system required compatibility with both urea and hydrocarbon-based dosing agents. It also needed to ensure continued engine interface flexibility. The testing was conducted either with independent dosing system operations or integration with a direct electronic control unit. The prospective customer was finding a general lack of commercially available products to meet such stringent needs.
With its North American headquarters in Marlborough, Massachusetts, HBM (www.hbm.com) is a leading manufacturer of rugged, lab and high-speed data acquisition systems (DAQ) and professional analysis software for testing requirements. This includes high-reliability torque, force and pressure measurement instrumentation, incorporating world-leading strain gauge technology.
For more than 60 years, HBM has been helping automotive engineers to meet regulatory compliance and other requirements for fleet vehicle testing, including emissions, durability and fatigue, vehicle dynamics, structural testing, noise, vibration and harshness (NVH), road load data acquisition (RLDA) and others. The customer made a final decision to work with HBM due to its extensive automotive DAQ expertise, excellence in technical support, and field-proven pedigree within similar applications.
Supporting emissions testing with HBM SoMat
Fleet emissions testing was conducted across approximately thirty trucks. Each vehicle required engineers to collect separate engine performance and NOx emissions data. The data, including vehicle CAN messages, were collected using twelve mobile, rugged HBM SoMat eDAQlite data acquisition systems. At the same time, a second group of test vehicles used an additional full-sized eDAQ to measure truck acceleration and deceleration levels.
The modular, Ethernet-based HBM SoMat eDAQ is expressly designed for high-reliability in extreme environments. It provides onboard data processing, triggering, intelligent data storage, and complex computations within a single, sealed, standalone system. eDAQ provides up to 96 analog measurement channels, synchronous data (parallel), and sample rates of up to 100 kHz. A diverse range of signal conditioning is available to support analog, strain gauge, thermocouple, digital I/O, pulse counter, GPS and vehicle bus inputs. The system is also designed to be fully mobile, with 10-60 VDC input power and a 20G rated enclosure. It correlates physical data, vehicle bus messages, and GPS data to provide a highly accurate test snapshot. It is also fully scalable, with capability to seamlessly network multiple eDAQ systems for an infinite number of synchronous channels.
The eDAQlite, a more compact version of the eDAQ, provides 32 analog channels and the same high-performance specifications as its larger-channel counterpart. This version offers a sufficiently small footprint for ease of installation into space-constrained environments. Both systems incorporate a modular architecture, building from a main processor layer (the ECPU-PLUS for the eDAQ and the ELCPU for the eDAQlite). Other layers may be added at customer discretion to accommodate specific sensor inputs, digital I/O and vehicle network communications.
Within this application, the eDAQ and eDAQlite units allowed the customer to incrementally assess and adjust the performance of its NOx emissions control products. This dual approach netted a great deal of high-quality test data. However, the need remained for an easier transfer of onboard recorded data to local PCs for analysis and reporting.
Identifying time savings with HBM nCode
Onsite automotive test engineers were spending an average of 30 minutes per day per vehicle to download, filter, and analyze collected data. This amounted to fifteen hours of data collection time across thirty individual fleet vehicles. Post-collection, data was manually downloaded from each recorder and filtered through HBM nCode GlyphWorks (GlyphWorks).
GlyphWorks is a powerful test engineering data analysis software, the functionality of which is particularly well-suited for automotive durability and fatigue analysis. Designed to handle large amounts of data, the software provides a graphical, process-oriented environment in which to drag and drop analytical building blocks, creating a customized analysis workflow. GlyphWorks includes functions for time, frequency, and statistical analysis, as well as synchronized GPS and video displays. For fleet vehicle testing, GlyphWorks is particularly useful in supporting the effective standardization of test procedures. Within this application, the software helped the customer to determine the frequency and duration of fleet vehicle emissions. Afterward, collected data were uploaded into HBM nCode automation software.
The customer use of nCode allowed for automated data storage, analysis and reporting. nCode also features a web-based collaborative interface for test data and other information sharing among multiple engineers. This powerful and scalable storage, analysis, and reporting platform enables engineers to better process and analyze both trending and relationship data. The software further allows for complex query creation, without having to write SQL or learn underlying database structure.
In this process, the customer identified a new workflow bottleneck associated with transferring recorded data to the nCode software. To address this, a 3D modem was incorporated into each truck to facilitate remote wireless data transmission. HBM also created a custom software program that could effectively download recorded messages automatically at timed intervals. These messages were also uploaded to nCode for later collaborative analysis. With the software, the customer was also able to upload stored drive data onto other fleet testing and test bench systems. This created a more universal capability for the customer to improve its data acquisition and analysis efficiencies.
Achieving a 93% reduction in data collection time
Implementation of the HBM solution, comprised of SoMat data acquisition systems; nCode software; a secondary custom automatic data download program; remote wireless data transmission capabilities; and automated workflows proved highly effective in streamlining fleet vehicle data collection. What had once been a fifteen-hour process was now less than a one-hour task across all thirty trucks, without sacrificing data quality and quantity. This represents a 93% tangible time reduction over prior methods. Efficiencies achieved by this solution further allowed the HBM customer to reallocate engineering resources away from data management, toward additional refinements of its NOx SCR emissions control products. The newly created additional engineering resource also served to potentially improve customer product time-to-market metrics. For HBM, it offers the dual benefit of introducing a complete, field-proven, streamlined measurement solution to address the stringent requirements of heavy truck fleet vehicle emissions testing.