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Solid and metallic ash particle number (PN) and particulate matter (PM) mass emission measurements were performed on a heavy-duty (HD) on-highway diesel engine and a compressed natural gas (CNG) engine. Measurements were conducted under transient engine operation that included the FTP, WHTC and RMC. Both engines were calibrated to meet CARB ultra low NOX emission target of 0.02 g/hp-hr, a 90% reduction from current emissions limit. The HD diesel engine final exhaust configuration included a number of aftertreatement sub-systems in addition to a selective catalytic reduction filter (SCRF). The stoichiometric CNG engine final configuration included a closed coupled Three Way Catalyst (ccTWC) and an under floor TWC (ufTWC). The aftertreatment systems for both engines were aged for a full useful life (FUL) of 435,000 miles, prior to emissions testing. PM mass emissions from both engines were comparable and well below the US EPA emissions standard.

Diesel engines are the primary power source for the medium and heavy-duty truck applications in the US. There is a wide range of regulatory developments being considered in the US that would impact the field of diesel engines and aftertreatment systems, such as the California Air Resources Board’s (CARB) low NOX standards and the extended durability requirement for aftertreatment systems. The proposed durability standards would require manufacturers to develop aftertreatment systems targeting up to 800,000 miles of full useful life (FUL) for Heavy heavy-duty (HHD) Application. Robust design and validation of aftertreatment systems is critical to ensure compliance with such stringent regulations. Several methodologies are being considered by the regulatory agencies for the compliance validation process, including the option of accelerated aging of the aftertreatment systems for a portion of the FUL.

In recent years, gasoline direct injection (GDI) engines have been widely used by manufacturers in light-duty to meet stringent fuel economy and emissions standards. This study focuses on the relationship between various particle metrics such as number, size, surface area and mass of dilute exhaust particles from 12 different light-duty vehicles equipped with GDI engines. The campaign included the measurement of total particulate matter (PM) using Title 40 CFR Part 1066 compliant filter measurement, soot mass using photo-acoustics based analyzer, organic carbon (OC) & elemental carbon (EC) mass using thermo-optical analysis of quartz filter samples, solid particle number using European Union Regulation No. 49 compliant number system and solid particle size/number using an electrical mobility based size spectrometer.

The engine power cylinder is comprised of the piston, piston rings, and cylinder. It accounts for a significant amount of total engine friction within reciprocating, internal combustion engines. Reducing power cylinder friction is key to the development of efficient internal combustion engines. However, isolating individual power cylinder tribocouples for detailed analysis can be challenging. In this work, a new reciprocating liner test rig is developed and introduced. The rig design is novel, using a stationary piston and a reciprocating cylinder liner. Friction is calculated from the force measured in the connecting rod which supports the piston. The rig allows for independent control of peak cylinder pressure, speed, and lubricant temperature. Using the newly developed test rig, several technologies for friction reduction are evaluated and compared.

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.

Engine start-up (cranking) can be an important source of particle emissions from vehicles. With the penetration of GDI vehicles in the global vehicle fleet, it is important to analyze and understand the contribution of start-up particle emissions from GDI vehicles, and the potential effects of fuel properties on that process. In this work, chassis dynamometer based investigation on the effect of several gasoline fuels (commercial and blended) on both, naturally aspirated and turbocharged GDI vehicles were conducted to understand the importance of engine start up, in particular, cranking. 10 commercially available gasoline fuels were tested on a naturally aspirated 2010 model year GDI vehicle, 3 among these commercially available fuels were tested on another 2009 model year turbocharged GDI vehicle, and 8 blended gasoline fuels were tested on 12 other GDI vehicles (7 turbocharged and 5 naturally aspirated) ranging in model years 2011-2015.

Increasingly stringent fuel economy and emissions regulations around the world have forced the further optimization of nearly all vehicle systems. Many technologies exist to improve fuel economy; however, only a smaller sub-set are commercially feasible due to the cost of implementation. One system that can provide a small but significant improvement in fuel economy is the lubrication system of an internal combustion engine. Benefits in fuel economy may be realized by the reduction of engine oil viscosity and the addition of friction modifying additives. In both cases, advanced engine oils allow for a reduction of engine friction. Because of differences in engine design and architecture, some engines respond more to changes in oil viscosity or friction modification than others. For example, an engine that is designed for an SAE 0W-16 oil may experience an increase in fuel economy if an SAE 0W-8 is used.

To meet increasingly stringent emissions and fuel economy regulations, many Original Equipment Manufacturers (OEMs) have recently developed and deployed small, high power density engines. Turbocharging, coupled with gasoline direct injection (GDI) has enabled a rapid engine downsizing trend. While these turbocharged GDI (TGDI) engines have indeed allowed for better fuel economy in many light duty vehicles, TGDI technology has also led to some unintended consequences. The most notable of these is an abnormal combustion phenomenon known as low speed pre-ignition (LSPI). LSPI is an uncontrolled combustion event that takes place prior to spark ignition, often resulting in knock, and has been known to cause catastrophic engine damage. LSPI propensity depends on a number of factors including engine design, calibration, fuel properties and engine oil formulation. Several engine tests have been developed within the industry to better understand the phenomenon of LSPI.

Downsized gasoline engines, coupled with gasoline direct injection (GDI) and turbocharging, have provided an effective means to meet both emissions standards and customers’ drivability expectations. As a result, these engines have become more and more common in the passenger vehicle marketplace over the past 10 years. To maximize fuel economy, these engines are commonly calibrated to operate at low speeds and high engine loads – well into the traditional ‘knock-limited’ region. Advanced engine controls and GDI have effectively suppressed knock and allowed the engines to operate in this high efficiency region more often than was historically possible. Unfortunately, many of these downsized, boosted engines have experienced a different type of uncontrolled combustion. This combustion occurs when the engine is operating under high load and low speed conditions and has been named Low Speed Pre-Ignition (LSPI). LSPI has shown to be very damaging to engine hardware.

In this study, a high-efficiency heavy-duty diesel engine platform was used to evaluate gasoline compression ignition (GCI) operation. The experiment was carried out using a single-cylinder engine (SCE) of a high compression ratio (22:1). Pump-grade gasoline fuel 87 research octane number (RON) was used throughout engine testing. Injection strategy was established including double and triple injection schemes to optimize both engine efficiency and emissions. Both low-temperature heat release (LTHR) and high-temperature heat release (HTHR) were seen from a two-stage combustion event resulting from the interaction of pilot and main injections. At low load conditions, besides fuel stratification level by pilot/main injection strategy, higher in-cylinder pressure can greatly improve the ignition of 1st stage combustion. As engine load increases, spray-wall interaction becomes more critical on engine efficiency and emissions performance.

Conventional diesel combustion (CDC) is known to provide high efficiency and reliable engine performance, but often associated with high particulate matter (PM) and nitrogen oxides (NOX) emissions. Combustion of fossil diesel fuel also produces carbon dioxide (CO2), which acts as a harmful greenhouse gas (GHG). Renewable and low-carbon fuels such as renewable diesel (RD) and methanol can play an important role in reducing harmful criteria and CO2 emissions into the atmosphere. This paper details an experimental study using a single-cylinder research engine operated under dual-fuel combustion using methanol and RD. Various engine operating strategies were used to achieve diesel-like fuel efficiency. Measurements of engine-out emissions and in-cylinder pressure were taken at test conditions including low-load and high-load operating points.

Particulate matter (PM) and NOX are two major pollutants generated by diesel engines. Modern diesel aftertreatment systems include selective catalytic reduction (SCR) technology that helps reduce tailpipe NOX emissions when coupled with diesel exhaust fluid (DEF/urea) injection. However, this process also results in the formation of urea derived byproducts that can influence non-volatile particle number (PN) measurement conducted in accordance with the European Union (EU) Particle Measurement Program (PMP) protocol. In this program, an experimental investigation of the impact of DEF injection on tailpipe PN and its implications for PMP compliant measurements was conducted using a 2015 model year 6.7 L diesel engine equipped with a diesel oxidation catalyst, diesel particulate filter and SCR system. Open access to the engine controller was available to manually override select parameters.

According to the Annual Energy Outlook 2022 (AEO2022) report, almost 30% of the transport sector will still use internal combustion engines (ICE) until 2050. The transportation sector has been actively seeking different methods to reduce the CO2 emissions footprint of fossil fuels. The use of lower carbon-intensity fuels such as Renewable Diesel (RD) can enable a pathway to decarbonize the transport industry. This suggests the need for experimental or advanced numerical studies of RD to gain an understanding of its combustion and emissions performance. This work presents a numerical modeling approach to study the combustion and emissions of RD. The numerical model utilized the development of a reduced chemical kinetic mechanism for RD’s fuel chemistry. The final reduced mechanism for RD consists of 139 species and 721 reactions, which significantly shortened the computational time from using the detailed mechanism.

Modern agriculture has evolved dramatically over the past half century. To be profitable, farms need to significantly increase their crop yields, and thus there are amplified demands on farming equipment. Equipment duty cycles have been raised in scope and duration, as the required output of the agricultural industry to sustain a growing population has stimulated the need for further advances in effective productivity gains on the farm. The mainstay mechanical assistant to the farmer, the tractor, has also evolved with the changes in modern agriculture to meet the requirements of these newer tasks. Larger, more capable vehicles have been introduced to help farmers efficiently meet these demands. At the same time, the current generation of tractor diesel engine lubricants has facilitated high levels of performance in the agricultural equipment market for many years. This is a testament to the role modern lubricants play in productivity in such a critical industry.

California Air Resources Board (CARB) has instituted requirements for on-board diagnostics (OBD) that makes a spark-plug sized exhaust particulate matter (PM) sensor a critical component of the OBD system to detect diesel particulate filter (DPF) failure. Currently, non-real-time resistive-type sensors are used by engine OEMs onboard vehicles. Future OBD regulations are likely to lower PM OBD thresholds requiring higher sensitivity sensors with better data yield for OBD decision making. The focus of this work was on the experimental evaluation of a real-time PM sensor manufactured by EmiSense Technologies, LLC that may offer such benefits. A 2011 model year on-highway heavy-duty diesel engine fitted with a diesel oxidation catalyst (DOC) and a catalyzed DPF followed by urea-based selective catalytic reducer (SCR) and ammonia oxidation (AMOX) catalysts was used for this program.

In this work, a novel bearing test rig was used to evaluate the impact of oil viscoelasticity on friction torque and oil film thickness in a hydrodynamic journal bearing. The test rig used an electric motor to rotate a test journal, while a hydraulic actuator applied radial load to the connecting rod bearing. Lubrication of the journal bearing was accomplished via a series of axial and radial drillings in the test shaft and journal, replicating oil delivery in a conventional engine crankshaft. Journal bearing inserts from a commercial, medium duty diesel engine (Cummins ISB) were used. Oil film thickness was measured using high precision eddy current sensors. Oil film thickness measurements were taken at two locations, allowing for calculation of minimum oil film thickness. A high-precision, in-line torque meter was used to measure friction torque. Four test oils were prepared and evaluated.

In this study, engine-out gaseous emissions are reviewed using the Fourier Transform Infrared (FTIR) spectroscopy measurement of methanol diesel dual fuel combustion experiments performed in a heavy-duty diesel engine. Comparison to the baseline diesel-only condition shows that methanol-diesel dual fuel combustion leads to higher regulated carbon monoxide (CO) emissions and unburned hydrocarbons (UHC). However, NOX emissions were reduced effectively with increasing methanol substitution rate (MSR). Under dual-fuel operation with methanol, emissions of nitrogen oxides (NOX), including nitric oxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O), indicate the potential to reduce the burden of NOX on diesel after-treatment devices such as selective catalytic reduction (SCR).

As an alternative fuel, renewable diesel (RD) could improve the performance of conventional internal combustion engines (ICE) because of its difference in fuel properties. With almost no aromatic content in the fuel, RD produces less soot emissions than diesel. The higher cetane number (CN) of RD also promotes ignition of the fuel, which is critical, especially under low load, and low reactivity conditions. This study tested RD fuel in a heavy-duty single-cylinder engine (SCE) under compression-ignition (CI) operation. Test condition includes low and high load points with change in exhaust gas recirculation (EGR) and start of injection (SOI). Measurements and analysis are provided to study combustion and emissions, including particulate matters (PM) mass and particle number (PN). It was found that while the combustion of RD and diesel are very similar, PM and PN emissions of RD were reduced substantially compared to diesel.

Gasoline direction injection (GDI) engines have been widely used by light-duty vehicle manufacturers in recent years to meet stringent fuel economy and emissions standards. Particulate Matter (PM) mass emissions from current GDI engines are primarily composed of soot particles or black carbon with a small fraction (15% to 20%) of semi-volatile hydrocarbons generated from unburned/partially burned fuel and lubricating oil. Between 2017 and 2025, PM mass emissions regulations in the USA are expected to become progressively more stringent going down from current level of 6 mg/mile to 1 mg/mile in 2025. As PM emissions are reduced through soot reduction, lubricating oil derived semi-volatile PM is expected to become a bigger fraction of total PM mass 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.