Overview
The Emissions and Fuels research team at CE-CERT, including national and international research leaders, is applying advanced technologies and methods to the measurement of emissions from all types of engines, including cars and light-duty trucks, heavy-duty freight trucks and construction equipment, and the large engines that power marine vessels. CE-CERT has considerable experience with successfully completing complex projects that involve elements of laboratory testing, fieldwork, activity measurements, and PEMS evaluations and implementations.
Research Projects
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Medium and Heavy-Duty EV Deployment - Data Collection
The number of plug-in and electric vehicle models in the medium-duty (MD) and heavy-duty (HD) category has significantly expanded in recent years. Along with that, a growing number of fleets are deploying or are interested in deploying electric vehicles such as transit buses, school buses, trucks, and off-road equipment. With this rapid growth of electric vehicles in the market, reliable operation and performance data on electric MD and HD vehicles is needed to provide insights on usage and to support the ongoing research into the future deployment. The focus of this project is to collect operations and performance data on MD and HD electric vehicles primarily and much smaller subset of LD electric vehicles. The project will build on deployment efforts underway in several regions across the country that include: a) electric transit buses (transit properties in NY, IL, UT, and CA), b) electric school buses (school districts in NY and CA), c) electric trucks (several large projecs involving truck fleets and goods movement operations in CA), d) electric off-road equipment (ports, goods movement facilities in CA), e) EVs for clean mobility solutions or workplace. The data will be collected using on-board data loggers and established data collection protocols, based on extensive experience of the project team. Several different types of data loggers may be used. CALSTART and CE-CERT have a large number of data loggers that we have been using on vehicle data colleciton projects and that will be available to be used in this project. Other data loggers will may be pre-installed by the original equipment manufacturers (OEMs), or provided by a third-party telematics provider as selected by the fleet. We will also seek participation from the OEMs to insure that data can be successfully captured from each vehicle. Data collection test plans and protocols will be standardized, as much as possible, to ensure uniformity across the projects. Data will include: 1) vehicle performance data , 2) charging data from off-board chargers, 3) electricity consumption data, 4) other facility data, and 5) climate data. These data will be collected in addition to vehicle desciption data such as make, model, year, and battery capacity. Data will be collected over a period of at least 12 months from the individual projects and stored centrally in CALSTART’s and/or CE-CERT’s secured data servers. The data will be verified, cleaned, anonymized, and analyzed using clearly defined steps and uniform processes across all vehicles. We will collaborate with colleagues at NREL to inform the definitions of parameters and format of the raw data and ensure alignment with existing database requirements before providing it to the designated Department of Energy natinal lab. Analyses will be peformed to provide summarized results, including tables, charts, and other visuals. All data collected through this project will be made available for download via FTP or similar protocol and accessible only to those who are provided access.
Lead Researcher: Dr. Kent Johnson Co-researchers: Dr. Kanok Booriboonsomsin, Dr. Thomas Durbin
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OSAR: Phase 1 Sensor Evaluation on Heavy Duty Trucks
Heavy-duty vehicles represent one of the most important contributions to the emissions inventory for both nitrogen oxides (NOx) and particulate matter (PM) emissions. Heavy-duty engines have been subjected to increasingly more stringent standards over the years. The latest round of standards essentially requiring the use of diesel particulate filters (DPFs) and selective catalytic reduction (SCR) to meet the PM and NOx emissions standards, respectively. While these aftertreatment systems have provided significant reductions in PM and NOx emissions, it is important to verify that these systems are operating optimally under the full range of in-use conditions to ensure that air quality standards can be met. This is particularly true in the South Coast Air Quality Management District (SCAQMD), where it is projected that mobile source NOx emission levels will need to be reduced significantly to meet the 2023 and 2031 ozone standards. The heavy-duty diesel SCR equipped engine has reduced NOx emissions, by 90%, from previous levels when tested on the certification cycle, but not during in-use operation. Compliant 2010 vehicles were found to have NOx emissions ten times higher than the certification limit on low power test cycles, but meeting the limit on certification like cycles, (Dixit et al, 2017, Misra et al., 2013, Quiros et al., 2017, and Lee et al., 2018). Studies with ultra-low NOx natural gas engines have demonstrated emissions well below the current standard, as much as 100 times lower, even during low power test cycles (Johnson et al 2017 and 2018). Zero emission and hybrid trucks show the ability for zero emissions, but unfortunately their wide spread use is low. A dynamic standard, such as a zero emissions or ultra-low NOx zone, could be utilized which would encourage different technologies in urban areas where in-use NOx emissions are much higher than the standards. The Air Resource Board is proposing a low-NOx standard of 0.02 g/bhp-hr, a low power test cycle, and revisions to the Not-To-Exceed compliance test to try and close the gap between certification and in-use. A different solution is to measure all the trucks all the time with on board sensing and validate compliance from the in-use fleet under the conditions where they produce emissions. It is suggested, that there will always be a gap between our standards (policy) and the in-use emissions (real exposure) until we focus on the in-use for our compliance and certification methods. Agencies, industry and academia are in agreement that “in-use” is where we need to focus, so it is time to start thinking this way in our standards. Complying with in-use conditions will be a challenge and will require a change from laboratory or portable emissions measurement system (PEMS) testing to an on-board continuous measurement and reporting system. The system proposed here is called Onboard Sensing, Analysis, and Reporting (OSAR). OSAR utilizes sensors technology that is borrowed from the vehicles embedded control system. These control sensors have been studied and are relatively accurate, repeatable, and very durable. Tan et al., (2018) evaluated the in-use NOx emission rates from the on-board diagnostic (OBD) sensors of 72 HDDVs. They found that high NOx emissions were still a common problem in from in-use heavy-duty diesel fleets, primarily due to low SCR conversion efficiencies during low temperature operation and potentially from malfunctioning SCRs. Montes (2018) compared these same OBD sensors with the laboratory and found that the sensors on average were with-in 15% (with a range from -5% to +50%) of the laboratory measurement. The laboratory NOx emissions ranged from 2.5 to 0.046 g/bhp-hr and the OBD NOx sensor emissions ranged from 2.6 to 0.061 g/bhp-hr. The wide range of data between vehicles is significantly more important than the slight difference between the measurements. One significant concern with the OBD NOx sensor is that they are disabled below 250 C to prevent humidity damage to the ceramic sensing element. NGK-sparkplugs, a large manufacturer of OBD NOx sensors, developed prototypes that operate at lower conditions than the OBD sensors and also improved their accuracy. The low temperature conditions are important because this is where the highest NOx emissions are generated for SCR equipped diesel engines. Yang et al. (2018) utilized this prototype sensor and found NOx measurements were within approximately ±10% of those the full 1065 compliance PEMS system over a range of driving conditions and emissions sources from 15 g/bhp-hr to 0.2 g/bhp-hr including cold start conditions. The overall goal of this research is to create an on-board reporting system to guide the industry into a sustainable path of emissions control for their vehicles using the real world as the design platform. The funds provided by AQMD will leverage larger dollars from industry as we demonstrate and consider in-use design methods for regulations. It is believed this seed funding will spur the industry into a solution that includes instrumenting all new heavy-duty trucks with ideas for retrofitting older ones depending on feedback from the Agencies. Also it is believed this proposal will be supported by the industry and fleets owners as it benefits everyone with a fair and practical solution for emissions regulations. Eventually other mobile sources will follow this patter including non-road and light duty passenger cars. The goal of this Phase 1 research proposal is to develop and demonstrate a low cost NOx and PM sensor-based emissions measurement designed for heavy duty engines. The low cost system would be designed to include future capabilities such as dynamic engine calibration control, in-use policy enforcement with a fine based method, and a data driven exposure model specific to the South Coast Air Basin.
Lead Researcher: Dr. Kent Johnson Co-researcher: Dr. Thomas Durbin
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Zero-and-Near-Zero Emissions Freight Facility Grant
The University of California at Riverside (UCR) will provide support for data logging and potentially portable emissions measurement systems (PEMS) testing, and chassis dynamometer. This will be conducted in support of the Port of Long Beach’s (POLB) prime contract effort with the California Air Resources Board (CARB) under the zero- and near-zero freight facility proposal. For a subset of equipment/vehicles, UCR will process and analyze the collected data to determine activity patterns including hours of operation, days of operation per year, miles traveled per day (and associated odometer reading per day and per shift if shift times are provided), average value and distribution of speed and acceleration, and idling time. We will analyze the performance of the vehicle/equipment in terms of the state of charge (SOC) throughout the work shift (minute-by-minute), fuel/energy consumption rate per work completed/distance driven, and fuel/energy consumption while idling. UCR can also provide for two weeks of PEMS testing, including travel to the site, installation and equipment preparation on-site, and actual testing. UCR can also provide for chassis dynamometer testing for a wide range of advanced technology vehicles. The basic budget includes two days of chassis dynamometer testing with CE-CERT’s heavy-duty chassis dynamometer testing facility. Measurement could include emissions for vehicles powered by natural gas, diesel, or other liquid or gas-phase fuels, standard parameters for electric vehicles consistent with the test plan outline by UCR in its guidance document for the POLB, and a combination of both emissions and EV parameters for hybrids.
Lead Researcher: Dr. Thomas Durbin Co-researchers: Dr. Kent Johnson, Dr. Kanok Boriboonsomsin, Dr. Wayne Miller
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200 Vehicle Study
UC Riverside is a leading research institute in the area of over the road/real-world vehicle testing. Over the past 5 years, UC Riverside has played a central role in the validation of portable emissions measurement systems (PEMS) systems for use in EPA’s in-use testing program of heavy-duty vehicles thought the Measurement Allowance Program. As part of this program, UC Riverside conducted in the in-use testing validation portion of this program utilizing UC Riverside’s Mobile Emissions Laboratory (MEL). The MEL is a full dilution system equipped in a 53’ trailer that is 1065 compliant and was cross correlated twice with Southwest Research Institute as part of the Measurement Allowance program. The in-use evaluations and validation played in critical role in developing the Measurement Allowance values for both gas-phase and PM PEMS.
UC Riverside has also been a leading research institute in the characterization of in-use emissions using PEMS and the MEL. This has included measurements of light-duty vehicles, heavy-duty vehicles, construction equipment, ships, port support equipment, trains, and even jet aircraft. As part of these studies, UC Riverside has construction some of the most comprehensive PEMs systems. This includes a PEMS system based around the AVL microsoot sensor (MSS) with either an AVL or Sensor Inc. gas-phase PEMS. The AVL MSS was the best performing instrument for in-use PM measurements in EPAs Measurement Allowance program. We have utilized this system installed on construction equipment as part of program for CARB and Caltrans, as well as for on-road truck testing as part of the Measurement Allowance and other programs. UC Riverside has a separate PEMS system based on a Horiba PG350 portable multi-gas analyzer for steady state measurements in compliance with ISO 8178. This PEMS system has been utilized for testing on ships, of generators, and port support equipment. UC Riverside has developed protocols for technology verifications of emission control technologies for such applications as generators, marine vessels, and rubber tire gantry cranes.
Lead Researcher: Dr. Thomas Durbin