Center for Environmental Research & Technology

Fuels

UC Riverside is a recognized leader in the area of fuels research, which is conducted through the Emissions and Fuels Research (EFR) Group. The EFR includes 8 faculty researchers and professors that are among the leading experts in the area of emissions and fuels, including Drs. Tom Durbin, Wayne Miller, Kent Johnson, Robert Russell, David Cocker, Joe Norbeck, Heejung Jung, and Georgio Karavalakis. Dr. Miller and Russell each have over 20 years of direct experience in the oil and additive industry and have developed and patented some of the most progressive formulations for diesel fuels and gasoline that are currently on the market. Drs. Durbin and Miller have conducted some of the most comprehensive studies conducted in a number of areas including a number of large Coordinating Research Council programs (E-60, E-61, E-67, and E-83), the largest biodiesel emissions study conducted to date in conjunction with CARB, and the largest study of biodiesel for the Department of Defense. Dr. Karavalakis is a European expert in the area of fuels that has recently been added to the EFR group.

In-Use/Portable Emission Measurement Systems

Over the past five 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 through the Measurement Allowance Program. As part of this program, UC Riverside conducted 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.

We have recently been utilizing this system installed on construction equipment as part of program for CARB and Caltrans. UC Riverside has a separate PEMS system based on a Horiba PG250 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.

Particles

The Center also was the prime contractor for a CARB research program to evaluate the European Particle Measurement Program (PMP) protocols for diesel solid nanoparticle emissions. The specific objective of this study was to critically evaluate the proposed PMP method for determining “solid” particle number emissions from heavy-duty vehicles in the laboratory and during over-the-road driving.

For this program, testing was conducted on the chassis dynamometer at the CARB heavy-duty vehicle emissions laboratory in Los Angeles and over the road with the CE-CERT mobile emissions laboratory (MEL). Comparisons were made between two different PMP compliant dilutions systems for measuring solid particle number, in conjunction with a full suite of other particle instruments for measuring particle size and number concentration, including an EEPS, a Cambustion DMS, CPCs with cut-off size ranges from 3 to 20 nm, a Dekati DMM, and a TSI Dustrak. CE-CERT is currently working on a follow up to this initial program, in which a device known as a “Catalytic Stripper” is being compared to a PMP compliant solid particle measurement system.

The later program includes a complete set of tests to characterize the catalytic stripper and PMP system with model aerosols, and chassis dynamometer and on-road tests to characterize these system with raw exhaust.

Port-Related Activities

CE-CERT has been investigating port emissions since 2003, first from locomotives and later drayage vehicles and equipment. More recently the Center has also studied emissions from harbor craft, ferries and ocean going vessels.

Massive port facilities use diesel power to load and unload container ships, as well as to move cargo in and out of the area. The twin Ports of Los Angeles and Long Beach are among the largest contributors to air pollution in the South Coast Basin.

The group has recently begun developing some of the earliest comprehensive emissions profiles of different ocean going vessel engine designs and fuels. The center also was a partner on the first study of lower sulfur marine fuels in the Gulf of Mexico by the U.S. EPA and the Mexican Federal Government. Studies have also evaluated hybrid technologies for drayage vehicles and harbor craft.

Measurements on ships identified two metallic particulates in stack emissions -- vanadium and nickel -- which were used as tracers for downwind dispersal, detected 50 miles inland.

Emissions Modeling

The Comprehensive Modal Emissions Model (CMEM) was initially developed in the late 1990's, with sponsorship from the National Cooperative Highway Research Program (NCHRP) and the U.S. Environmental Protection Agency (EPA) to fulfill the need for microscopic emissions modeling. This type of model is necessary for evaluating emissions benefits of project-level or corridor-specific transportation control measures (e.g., HOV lanes), intelligent transportation systems (ITS) implementations (e.g., electronic toll collection), and traffic flow improvements (e.g., traffic signal coordination).

CMEM is an open source research tool for those who have the need to view traffic emissions at the “microscopic” level. Researchers investigating transportation system design, intelligent transportation systems, emissions from traffic simulation models, and many other areas where more precise localized measurements are essential, use CMEM as a physical model for fuel consumption estimation and pollutant emission prediction.

Released in 1995, CMEM was one of the first traffic emissions models to account for variations in vehicle operation at a more fundamental level. The wide range of emission behaviors found under various driving conditions such as acceleration, deceleration, idling, steady-state cruising, and congestion makes in-use urban driving emissions difficult to estimate. Emissions under such conditions vary greatly, and in such a way that “average speed” based emissions cannot easily express.

CMEM is distinct from most other models in at least two ways: it estimates emissions based on specific physical properties from each source vehicle; and it predicts second-by-second vehicle performance and emissions. One of the advantages of the CMEM model over conventional traffic emission models is that certain changes such as vehicle weight, aerodynamic characteristics, and additional accessory loads can be modeled without recalibration of vehicle categories.

The model was influential in the development of the U.S. EPA's official mobile source inventory model MOVES (MOtor Vehicle Emissions Simulator). The CMEM model has proven to be an exceptional research tool and was the basis for the simplified Physical Emission Rate Estimator (PERE) model which is part of EPA’s new MOVES modeling suite. MOVES emission factors are based on Vehicle Specific Power (VSP), a quantity which generalizes many of the same physical principles characterized by the CMEM model.

PERE gives MOVES users the ability to expand EPA’s emissions data model with customized local data from actual physical measurements. “The model is essentially an effort to simplify, improve, and implement the Comprehensive Modal Emissions Model (CMEM) developed at the University of California, Riverside,” wrote Edward K. Nam, formerly of Ford Research and Advanced Engineering, in his Proof of Concept document.

According to Nam, the engineering advances over the past two decades in engine design, fuel formulation, control systems, and catalysts have made the use of generalized VSP calculations possible in the MOVES model. Modern vehicles simply perform more consistently at different speeds, loads and grades.

Over the years, the CMEM project has built an invaluable inventory of physical emission data for several hundred vehicles and traffic emission models for numerous automobile categories. As an open source model, CMEM has attracted more than a hundred registered users worldwide.