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Internal combustion engines (ICE) will be a part of personal transportation for the foreseeable future. One recent trend for engines has been downsizing which enables the engine to be run more efficiently over regulatory drive cycles. Due to downsizing, engine power density has increased which leads to problems with engine knock. Therefore, there is an increasing need to find a means to reduce the knock propensity of downsized engines. One of the ways of reducing knock propensity is by introducing Exhaust Gas Recirculation (EGR) into the combustion chamber, however, volumetric efficiency also reduces with EGR which places challenges on the boosting system. The individual benefits of high-pressure (HP-EGR) and low-pressure (LP-EGR) loop EGR system to assist the boosting system of a 2.0 L Gasoline Direct Injection (GDI) production engine are explored in this paper.

This paper describes a new method for measuring oil consumption using laser induced breakdown spectroscopy (LIBS). LIBS focuses a high energy laser pulse on a sample to form a transient plasma. As the plasma cools, each element produces atomic emission lines which can be used to identify and quantify the elements present in the original sample. In this work, a LIBS system was used on simulated engine exhaust with a focus on quantifying the inorganic components (termed ash) of the particulate emissions. Because some of the metallic elements in the ash almost exclusively result from lube oil consumption, their concentrations can also be correlated to an oil consumption rate. Initial testing was performed using SwRI’s Exhaust Composition Transient Operation Laboratory®(ECTO-Lab®) burner system so that oil consumption and ash mass could be precisely controlled.

Southwest Research Institute (SwRI) utilizes the burner-based Exhaust Composition Transient Operation LaboratoryTM (ECTO-Lab) to accurately simulate transient engines and replicate real exhaust that is produced by light and heavy-duty engines for aftertreatment aging and evaluations. This system can generate and dose NOX over transient cycles from a range of 20 ppm to 1200 ppm where the NOX is generated by the in-situ decomposition and combustion of a fuel-bound, nitrogen containing compound. During the combustion and decomposition of the nitrogen containing compound over 95 % of the NOX generated is in the form of NO. To authentically simulate exhaust gases, it is necessary to account for the distribution of the NO to the NO2. Since previous work has established that the decomposition of nitric acid can be utilized as a method to generate NO2, the objective of this project was to develop control of NO and NO2 within SwRI’s ECTO-Lab through the decomposition of nitric acid.

Internal short-circuit in cells/batteries is a phenomenon where there is direct electrical contact between the positive and negative electrodes leading to thermal runaway. The nail penetration tests were used to simulate an internal short circuit within the battery, where a conductive nail was used to pierce the battery cell separator membrane which provided direct electrical contact between the positive and negative electrodes. The batteries tested during this work were common batteries used in existing automotive applications, and they included a nickel manganese cobalt (NMC) battery from a Chevrolet Bolt, a lithium manganese oxide (LMO) battery from a Chevrolet Volt, and a lithium iron phosphate (LFP) battery in a hybrid transit bus. The battery abuse and emissions tests were designed to intentionally drive the three different battery chemistries into thermal runaway while measuring battery temperatures, battery voltages and gaseous emissions.

The commercial vehicle industry continues to move in the direction of improving brake thermal efficiency while meeting more stringent diesel engine emission requirements. This study focused on demonstrating future emissions by using an exhaust burner upstream of a conventional aftertreatment system. This work highlights system results over the low load cycle (LLC) and many other pertinent cycles (Beverage Cycle, and Stay Hot Cycle, New York Bus Cycle). These efforts complement previous works showing system performance over the Heavy-Duty FTP and World Harmonized Transient Cycle (WHTC). The exhaust burner is used to raise and maintain the Selective Catalytic Reduction (SCR) catalyst at its optimal temperature over these cycles for efficient NOX reduction. This work showed that tailpipe NOX is significantly improved over these cycles with the exhaust burner.

Internal short-circuit in cells/batteries is a phenomenon where there is direct electrical contact between the positive and negative electrodes leading to thermal runaway. The nail penetration tests were used to simulate an internal short circuit within the battery, where a conductive nail was used to pierce the battery cell separator membrane which provided direct electrical contact between the positive and negative electrodes. The batteries tested during this work were common batteries used in existing automotive applications, and they included a nickel manganese cobalt (NMC) battery from a Chevrolet Bolt, a lithium manganese oxide (LMO) battery from a Chevrolet Volt, and a lithium iron phosphate (LFP) battery in a hybrid transit bus. The battery abuse and emissions tests were designed to intentionally drive the three different battery chemistries into thermal runaway while measuring battery temperatures, battery voltages and gaseous emissions.

In this work, a dynamically loaded hydrodynamic journal bearing test rig is developed and introduced. The rig is a novel design, using a hydraulic actuator with fast acting spool valves to apply load to a connecting rod. This force is transmitted through the connecting rod to the large end bearing which is mounted on a spinning shaft. The hydraulic actuator allows for fully variable control and can be used to apply either static load in compression or tension, or dynamic loading to simulate engine operation. A variable speed electric motor controls shaft speed and is synchronized to the hydraulic actuator to accurately simulate loading to represent all four engine strokes. A high precision torque meter enables direct measurements of friction torque, while shaft position is measured via a high precision encoder.

Commercial vehicles are moving in the direction of improving brake thermal efficiency while also meeting future diesel emission requirements. This study is focused on improving efficiency by replacing the variable geometry turbine (VGT) turbocharger with a high-efficiency fixed geometry turbocharger. Engine-out (EO) NOX emissions are maintained by providing the required amount of exhaust gas recirculation (EGR) using a 48 V motor driven EGR pump downstream of the EGR cooler. This engine is also equipped with cylinder deactivation (CDA) hardware such that the engine can be optimized at low load operation using the combination of the high-efficiency turbocharger, EGR pump and CDA. The exhaust aftertreatment system has been shown to meet 2027 emissions using the baseline engine hardware as it includes a close coupled light-off SCR followed by a downstream SCR system.

The transport of fuel-borne additives into the engine oil is a critical factor for the efficacy with which the additive functionality can be imparted on the engine. This paper describes the combination of Laser Induced Fluorescence (LIF) and Liquid Chromatography (LC) to determine the real-time additive concentrations and transfer ratios in a spark-ignition, 2-liter GM LHU engine. The current research used a continuous sample circuit from the engine sump which passed through an integrating cavity flow cell to enhance the LIF signal. In the absence of a fluorescence signature of any of the native additive species, a suitable fluorescing dye was selected to simulate the additive. After establishing rigorous calibration curves, LC was employed as a referee method to do a direct comparison with the LIF determined dye concentrations.

The U.S. Environmental Protection Agency (EPA) certifies gasoline deposit control additives for intake valve deposit (IVD) control utilizing ASTM D5500, a vehicle test using a1985 BMW 318i. Concerns with the age of the test fleet, its relevance in the market today, and the availability of replacement parts led the American Chemistry Council’s (ACC) Fuel Additive Task Group (FATG) to begin a program to develop a replacement. General Motors suggested using a 2.4L LE9 test engine mounted on a dynamometer and committed to support the engine until 2030. Southwest Research Institute (SwRI®) was contracted to run the development program in four Phases. In Phase I, the engine test stand was configured, and a test fuel selected. In Phase II, a series of tests were run to identify a cycle that would build an acceptable level of deposits on un-additized fuel. In Phase III, the resultant test cycle was examined for repeatability.

A push for more stringent emissions regulations has resulted in larger, increasingly complex aftertreatment solutions. In particular, oxides of nitrogen (NOX) and particulate matter (PM) have been controlled using two separate systems, selective catalytic reduction (SCR) and the catalyze diesel particulate filter (CDPF), or the functionality has been combined into a single device producing the SCR on filter (SCRoF). The SCRoF forgoes beneficial NO2 production present in the CDPF to avoid NH3 oxidation which occurs when using platinum group metals (PGM) for oxidation. In this study, mixed-metal oxides are shown to oxidize NO to NO2 without appreciable NH3 oxidation. This selectivity leads to enhanced performance when combined with a typical Cu-zeolite catalyst.

The short-term future direction of the automotive transportation sector is uncertain. Many governments and environmental localities around the world are proposing internal combustion engine (ICE) bans and enacting large subsidy programs for zero-tailpipe emissions vehicles powered by batteries or fuel-cells. Such policies can be effective in driving the consumer towards specific powertrains. The reason for such aggressive change is to reduce the sector’s carbon footprint. However, it is not clear if these proposals will reduce greenhouse gas (GHG) emissions. Emissions from raw material extraction, manufacturing, and power generation are shadowed by the focus on reducing the reliance on fossil fuel use. Emissions from non-tailpipe sources should also be considered before pushing for a rapid change to powertrains. Life-cycle analysis (LCA) can assess the GHG emissions produced before, during and after the life of a vehicle in a cradle-to-grave analysis.

Despite considerable progress over the last several decades, California continues to face some of the most significant air quality problems in the United States. These continued issues highlight the need for further mobile source NOX reductions to help California and other areas meet ambient air quality targets mandated by the U.S. EPA. Beginning in 2014, the California Air Resources Board (CARB) launched a program aimed at demonstrating technologies that could enable heavy-duty on-highway engines to reach tailpipe NOX levels up to 90% below the current standards, which were implemented in 2010. At the same time, mandated improvements to greenhouse gas emissions (GHG) require that these NOX reductions be achieved without sacrificing fuel consumption and increasing GHG emissions.

Simulating high amounts of exhaust gas recirculation in spark ignited engines to predict combustion using the currently available CFD modeling approaches is a challenge and does not always give reasonable matches with experimental observations. One of the reasons for the mismatch lies with the secondary circuit treatment of the ignition coil and the resulting energy deposition or a complete lack of it thereof. An ignition modeling approach is developed in this work which predicts the energy transfer from the electrical circuit to the gases in the combustion chamber leading to flame kernel growth under high EGR and high gas flow velocity conditions. Secondary circuit sub-model includes secondary side of the coil, spark plug and spark gap. The sub-model calculates the delivered energy to the gas based on given circuit properties and total initial electrical energy.

Water injection is an effective method for knock control in spark-ignition engines. However, the requirement of a separate water source and the cost and complexity associated with a fully integrated system creates a limitation of this method to be used in volume production engines. The engine exhaust typically contains 10-15% water vapor by volume which could be condensed and potentially stored for future use. In this study, the exhaust condensate composition was assessed for its use as an effective replacement for distilled water. Specifically, condensate samples were collected pre and post-three-way catalyst (TWC) and analyzed for acidity and composition. The composition of the pre and post-TWC condensates was found to be similar however, the pre-TWC condensate was mildly acidic. The mild acidity has the potential to corrode certain components in the intake air circuit.

The dedicated exhaust gas recirculation (D-EGR®) concept developed by Southwest Research Institute (SwRI) has demonstrated a thermal efficiency increase on several spark-ignited engines at both low and high-load conditions. Syngas (H2+CO) is produced by the dedicated cylinder (D-cyl) which operates at a rich air-fuel ratio. The syngas helps to stabilize combustion under highly dilute conditions at low loads as well as mitigating knock at high loads. The D-cyl produces all the EGR for the engine at a fixed rate of approximately 25% EGR for a four-cylinder engine and 33% EGR for a six-cylinder engine. The D-cyl typically runs up to an equivalence ratio of 1.4 for gasoline-fueled engines, beyond which the combustion becomes unstable due to the decreasing laminar burning velocity caused by rich conditions. Conventional active-fueled and passive pre-chambers have benefits of inducing multi-site ignition and enhancing turbulence in the main chamber.

The size and distribution of a vehicle’s tailpipe particulate emissions can have a strong impact on human health, especially if the particles are small enough to enter the human respiratory system. Gasoline direct injection (GDI) has been adopted widely to meet stringent fuel economy and CO2 regulations across the globe for recent engine architectures. However, the introduction of GDI has led to challenges concerning the particulate matter (PM) and particle number (PN) emissions from such engines. This study aimed to compare the particulate emissions of three SI combustion strategies: conventional SI, conventional stoichiometric low-pressure exhaust gas recirculation (LP-EGR), and Dedicated-EGR (D-EGR) at four specific test conditions. It was shown that the engine-out PM/PN for both the EGR strategies was lower than the conventional SI combustion under normal operating conditions. The test conditions were chosen to represent the WLTC test conditions.

With the increasing level of electrification of on-road, off-road and stationary applications, use of larger lithium-ion battery packs has become essential. These packs require large capital investments on the order of millions of dollars and pose a significant risk of self-annihilation without rigorous safety evaluation and management. Testing these larger battery packs to validate design changes can be cost prohibitive. A reliable numerical simulation tool to predict battery thermal runaway under various abuse scenarios is essential to engineer safety into the battery pack design stage. A comprehensive testing & simulation workflow has been established to calibrate and validate the numerical modeling approach with the test data for each of the individual sub model - electrochemical, internal short circuit and thermal abuse model. A four-equation thermal abuse model was built and validated for lithium-ion 21700 form factor cylindrical cells using NCA cathodes.

SCR-on-filter, or SCRoF, is an emerging technology for different market segments and vehicle applications. The technology enables simultaneous particulate matter trapping and NOX reduction, and provides thermal management and aftertreatment packaging benefits. However, there is little information detailing the lubricant derived exposure effects on functional SCR performance. A study was conducted to evaluate the impact of various oil consumption pathways on a light duty DOC and SCRoF aftertreatment system. This aftertreatment system was aged utilizing an engine test bench modified to enable increased oil consumption rates via three unique oil consumption pathways. The components were characterized for functional SCR performance, ash morphology, and ash deposition characteristics. This included utilizing techniques, such as SEM / EDS, to evaluate the ash structures and quantify the ash elemental composition.

Detailed characterization of particle emissions from three different engine technologies were performed, two of which were advanced technology engines. One of the engines was a nonroad Tier 4 Final emission regulation compliant 6.8L John Deere PSS 6068 diesel engine operated with its production calibration strategy. The other two engine platforms were advanced engine technologies whose controllers were developed by Southwest Research Institute (SwRI). These included a dual fuel Navistar MaxxForce 13L natural gas-diesel engine and a Cummins ISX 15L diesel engine. The dual fuel engine was operated in two distinct modes, conventional dual fuel (CDF) mode and low temperature reactivity controlled compression ignition (RCCI) mode. The Cummins ISX engine was operated using a “hot” or low EGR combustion strategy. For each engine technology, the test campaign involved steady-state test modes ranging from low speed low load to high speed high load conditions.