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Viewing 1 to 30 of 3850
2017-06-17
Journal Article
2017-01-9550
David Neihguk, M. L. Munjal, Arvind Ram, Abhinav Prasad
Abstract A production muffler of a 2.2 liter compression ignition engine is analyzed using plane wave (Transfer Matrix) method. The objective is to show the usefulness of plane wave models to analyze the acoustic performance (Transmission Loss, TL) of a compact hybrid muffler (made up of reactive and dissipative elements). The muffler consists of three chambers, two of which are acoustically short in the axial direction. The chambers are separated by an impervious baffle on the upstream side and a perforated plate on the downstream side. The first chamber is a Concentric Tube Resonator (CTR). The second chamber consists of an extended inlet and a flow reversal 180-degree curved outlet duct. The acoustic cavity in the third chamber is coupled with the second chamber through the acoustic impedances of the end plate and the perforated plate.
2017-06-05
Technical Paper
2017-01-1782
Jobin Puthuparampil, Henry Pong, Pierre Sullivan
Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature.
2017-06-05
Technical Paper
2017-01-1827
Michael J. Santora, Cyril Gbenga Ige, Jeff Otto, David Egolf
A muffler attached to an engine attenuates sound over a dedicated frequency range. This research involves the development of an active muffler that is keyed to the revolutions per minute (rpm) of the engine and suppresses the fundamental frequency being exhausted through the tailpipe. The active muffler consists of a tracking side-branch resonator terminated with a composite piezoelectric transducer. The use of an exponential horn as a resonating cavity and terminated with a composite piezoelectric transducer is presented. This would create Electromechanical Active Helmholtz Resonator (EMAHR) with a notch that can be moved between 100-1000 Hz. The use of acoustical-to-mechanical, mechanical-to-electrical, and analog-to-digital transformations to develop a system model for the active muffler are presented. These transforms will be presented as two-port network parameters. The use of two-port networks to model the electroacoustic system are a defining factor in the analysis.
2017-06-05
Technical Paper
2017-01-1791
David Neihguk, Shreyas Fulkar
Parametric model of a production hybrid (made up of reactive and dissipative elements) muffler for tractor engine is developed to compute the acoustic Transmission Loss (TL). The objective is to simplify complex muffler acoustic simulations without any loss of accuracy, robustness and usability so that it is accessible to all product development engineers and designers. The parametric model is a 3D Finite Element Method (FEM) based built in COMSOL model builder which is then converted into a user-friendly application (App) using COMSOL App builder. The uniqueness of the App lies in its ability to handle not only wide range of parametric variations but also variations in the physics and boundary conditions. This enables designers to explore various design options in the early design phase without the need to have deep expertise in a specific simulation tool nor in numerical acoustic modeling.
2017-06-05
Technical Paper
2017-01-1875
Martino Pigozzi, Flavio Faccioli, Carlo Ubertino, Davide Allegro, Daniel Zeni
Within recent years, passenger comfort has become a main focus for the automotive industry. The topic is directly connected to acoustics, since sounds and noises have a major impact on the well-being of vehicle occupants. The so-called “noise control” focuses on directly optimizing acoustic comfort by implementing innovative materials or geometries for automotive components and systems. One possibility to optimize the acoustics within a vehicle is connected to the phenomenon of sloshing in selective catalytic reduction (SCR) tanks. Sloshing is a noise which is generated during normal driving situations by the motion of the liquid in the tank. Until now, no valid procedure for measuring the sloshing noise in SCR tanks, or a specific acoustic target which the SCR tanks need to fulfill has been defined. For this reason, It's been developed a reproducible laboratory-based methodology to measure the sound generated by the tank to compare it with a defined sound pressure level target.
2017-06-05
Technical Paper
2017-01-1753
Jack Hall Riddle, Ya-Juan Bemman, Tom Frei, Sihui Wu, Ishang Padalkar
Demands for low-RPM operation are increasing in the automotive market. This requirement is largely driven by consumer and regulatory demand for vehicles which are more efficient in the use of fuel. As a result, modern engine and transmission technologies have been developed which permit engine operation at increasingly low RPM’s. The resulting low frequency exhaust noise is more difficult to attenuate than in vehicles in years past. At the same time, vehicles often have less packaging space for mufflers, when larger volume would otherwise be needed to attenuate the lower frequency firing order content. A further challenge is the demand for increasingly refined performance sounds from the exhaust systems of premium cars despite the technical obstacles involved in even maintaining sound quality. Finally, legally permissible sound levels are decreasing in some markets. These market and regulatory demands require new solutions.
2017-03-28
Technical Paper
2017-01-1333
Sasikumar P, C. Sujatha, Chinnaraj K.
Abstract In commercial vehicles, exhaust system is normally mounted on frame side members (FSM) using hanger brackets. These exhaust system hanger brackets are tested either as part of full vehicle durability testing or as a subsystem in a rig testing. During initial phases of product development cycle, the hanger brackets are validated for their durability in rig level testing using time domain signals acquired from mule vehicle. These signals are then used in uni-axial, bi-axial or tri-axial rig facilities based on their severity and the availability of test rigs. This paper depicts the simulation method employed to replicate the bi-directional rig testing through modal transient analysis. Finite Element Method (FEM) is applied for numerical analysis of exhaust system assembly using MSC/Nastran software with the inclusion of rubber isolator modeling, meshing guidelines etc. Finite Element Analysis (FEA) results are in good agreement with rig level test results.
2017-03-28
Technical Paper
2017-01-1709
Zhigang Wei, Sarat Das, Ryan Barr, Greg Rohrs, Robert Rebandt, Xiao Wu, HongTae Kang
Abstract Recent stringent government regulations on emission control and fuel economy drive the vehicles and their associated components and systems to the direction of lighter weight. However, the achieved lightweight must not be obtained by sacrificing other important performance requirements such as manufacturability, strength, durability, reliability, safety, noise, vibration and harshness (NVH). Additionally, cost is always a dominating factor in the lightweight design of automotive products. Therefore, a successful lightweight design can only be accomplished by better understanding the performance requirements, the potentials and limitations of the designed products, and by balancing many conflicting design parameters. The combined knowledge-based design optimization procedures and, inevitably, some trial-and-error design iterations are the practical approaches that should be adopted in the lightweight design for the automotive applications.
2017-03-28
Technical Paper
2017-01-0558
Lei Cui, Tianyou Wang, Kai Sun, Zhen Lu, Zhizhao Che, Yanzhe Sun
Abstract The scavenging process in two-stroke marine engines not only transports burnt gas out of the cylinder but also provides fresh air for the next cycle, thereby significantly affecting the engine performance. In order to enhance fuel-air mixing, the scavenging process usually generates swirling flow in uniflow-type scavenging engines. The scavenging stability directly determines the scavenging efficiency and even influences fuel-air mixing, combustion, and emission of the engine. In the present study, a computational fluid dynamics (CFD) analysis of the scavenging process in a steady-state scavenging flow test is conducted. A precession phenomenon is found in the high swirl model, and Proper Orthogonal Decomposition (POD) method is used to analyze the reason and the multi-scale characteristics of the precession phenomenon.
2017-03-28
Technical Paper
2017-01-0530
Ted Holmberg, Andreas Cronhjort, Ola Stenlaas
Abstract In one dimensional engine simulation software, flow losses over complex geometries such as valves and ports are described using flow coefficients. It is generally assumed that the pressure ratio over the valve has a negligible influence on the flow coefficient. However during the exhaust valve opening the pressure difference between cylinder and port is large which questions the accuracy of this assumption. In this work the influence of pressure ratio on the exhaust valve flow coefficient has been investigated experimentally in a steady-flow test bench. Two cylinder heads, designated A and B, from a Heavy-Duty engine with different valve shapes and valve seat angles have been investigated. The tests were performed with both exhaust valves open and with only one of the two exhaust valves open. The pressure ratio over the exhaust port was varied from 1.1:1 to 5:1. For case A1 with a single exhaust valve open, the flow coefficient decreased significantly with pressure ratio.
2017-03-28
Technical Paper
2017-01-0822
Jim Elkjær Bebe, Kasper Steen Andersen
Abstract The purpose of this work is to determine essential spray parameters for a specific nozzle to be integrated in computational fluid dynamics (CFD) simulations of selective catalytic reduction systems (SCR) based on the injection of urea water solution (UWS). As Dinex does not develop nozzles, but rather integrate nozzles from a variety of manufacturers, the spray data made available is of an inhomogeneous quality. This paper presents the results of a simple, partial validation and calibration of a CFD simulation performed with the commercial CFD code AVL FIRE 2014.2 using the Lagrangian discrete droplet method. The validation is based on a novel and low cost experimental setup, where the experimental method utilizes high-speed imaging to provide spray cone angle, axial spray penetration length and spray plume droplet density.
2017-03-28
Technical Paper
2017-01-1031
Xinyan Wang, Jun Ma, Hua Zhao
Abstract In this study, the effect of the intake plenum design on the scavenging process in a newly proposed 2-stroke Boosted Uniflow Scavenged Direct Injection Gasoline (BUSDIG) engine was studied in detail by three dimensional (3D) computational fluid dynamics (CFD) simulations. In the BUSDIG engine, the intake scavenge ports are integrated into the cylinder liner and their opening and closure are controlled by the movement of piston top while exhaust valves are placed in the cylinder head. In order to accommodate the optimized scavenge ports in the real engine application, the intake plenum with an inlet pipe and a scavenge chamber was designed and connected to the 12 evenly distributed scavenge ports in a single cylinder BUSDIG engine.
2017-03-28
Technical Paper
2017-01-0988
Michael Cunningham, Mi-Young Kim, Venkata Lakkireddy, William Partridge
Abstract Measuring axial exhaust species concentration distributions within a wall-flow aftertreatment device provides unique and significant insights regarding the performance of complex devices like the SCR-on-filter. In this particular study, a less complex aftertreatment configuration which includes a DOC followed by two uncoated partial flow filters (PFF) was used to demonstrate the potential and challenges. The PFF design in this study was a particulate filter with alternating open and plugged channels. A SpaciMS [1] instrument was used to measure the axial NO2 profiles within adjacent open and plugged channels of each filter element during an extended passive regeneration event using a full-scale engine and catalyst system. By estimating the mass flow through the open and plugged channels, the axial soot load profile history could be assessed.
2017-03-28
Technical Paper
2017-01-1081
Chongzhi Zhong, Tieqiang Fu, Chunbei Dai, Taiyu Zhang, Ke Wu, Wangwen Gu
Abstract In order to study the single cavity and double cavity canister work performance, the L/D, as well as the similarities and differences among the diameter of the adsorption mouth, purge mouth and air mouth have been studied. At the same time, the work performance of ORVR canister and common canister is also studied. The results demonstrate that the similar of L/D, efficient work ability and efficient adsorption rate of the double cavity canister is better than the single cavity canister. The bigger of L/D, the stronger work ability of the canister. However, the excessive increase of the L/D is not conducive to the canister desorption, instead resulting in the increase of RARCP. The adsorption mouth diameter of common canister is generally smaller or similar to the purge mouth, while for ORVR canister the adsorption mouth diameter is bigger than the purge mouth and similar to air mouth.
2017-03-28
Technical Paper
2017-01-1083
Chawin Chantharasenawong
Abstract This study focuses on achieving a lower overall lap time at SAE Formula Student competition through a modification to the standard intake system. The lower lap time is achieved by widening the range of engine RPM which produces torque higher than 90% of the maximum value and lowering the engine RPM corresponding to the maximum torque. An intake system with ‘variable runner length’ is introduced to the 2015 racecar of KMUTT team. The values of intake lengths are determined from the wave equation with the goal of producing over 90% of the maximum torque of the baseline configuration over a range of engine RPM. Computer simulations are performed to determine the pressure at engine entry at various runner lengths. Finally, a prototype variable runner length intake system with linear motor actuators is constructed and installed on the racecar. Chassis dynamometer tests are performed to determine the engine torque for 3,000 – 10,500 RPM at all interested runner lengths.
2017-03-28
Technical Paper
2017-01-1087
Pengfei Zang, Zhe Wang, Yu Fu, Chenle Sun
Abstract The Linear Internal Combustion Engine-Linear Generator Integrated System (LICELGIS) is different from conventional crank-based engine for reducing frictional losses by eliminating the crankshaft. Thus, the LICELGIS piston stroke is not constrained geometrically and the system compression ratio is variable. During steady-state operation, the LICELGIS converts the fuel chemical energy into electric power with piston assembly reciprocating motion, which can be used as a range-extender in hybrid electric vehicles. The LICELGIS scavenging process is prerequisite and key for the system steady-state operation, which has remarkable influence on mixture gas and, eventually, on engine combustion performance. In order to achieve high scavenging performance, a LICELGIS is investigated in this paper. The LICELGIS motion characteristics and scavenging process were analyzed.
2017-03-28
Technical Paper
2017-01-1078
Walid Ashraf, Sherif Khedr, Aya Diab, Hashim Elzaabalawy
Abstract A throttle valve is one of the main components of the intake system of a vehicle and is used to control the air flow rate into the combustion chamber at different engine speeds. Consequently, it has considerable effect on the engine power and performance especially at high engine speeds. The butterfly throttle valve is more common in commercial vehicles due to its simplicity. However, the butterfly throttle plate may affect the engine performance by incurring some pumping losses at high engine speeds even with the plate at wide open throttle (WOT) position. Hence it is proposed in this research work to replace and compare the performance of a spark ignition engine butterfly throttle valve to a newly designed barrel-shaped one with regards to the induced air mass flow rate. The main benefit of the proposed barrel-shaped throttle valve is the elimination of the flow restriction at WOT and high engine speeds.
2017-03-28
Technical Paper
2017-01-1079
Suresh Kumar Kandreegula, Sayak Mukherjee, Rahul Jain, Shivdayal Prasad, Kamal Rohilla
Abstract Flex Connectors are intended for mitigating the relative movement of exhaust system components along the axis of the system arising from the thermal expansion due to intermittent engine operation. Flex connectors must not be installed in locations, where they will be subjected to destructive vibration. Hence, the stiffness of the flex connector plays an important role, while designing or selecting the right design. It consists of a multi-ply bellows combined with an inside and an outside steel braid. The liner is included to reduce the temperature of the bellows and improve flow conditions. The braid is included for mechanical protection and to limit the possible extension of the joint. It has only axial translational motion.
2017-03-28
Technical Paper
2017-01-1076
Mohammad Moetakef, Abdelkrim Zouani, Esra Demren
Abstract In this presentation, two cases of CAE simulations of oil pump-induced tonal noises are presented. The first case involves oil pump-induced whine in an I4engine during coast down. The second case addresses oil pan moan during hot idle and the effect of oil pump pick-up tube positioning inside the oil pan of an I5 engine. The investigations include several design modifications to the pump and the pick-up tube to prevent the tonal noise. Test data are also included to demonstrate the accuracy of the CAE simulation.
2017-03-28
Technical Paper
2017-01-1077
Nicolas Arnault, Nicolas Batailley, Arnaud Maria, Laurent Bechu
Abstract PSA Group, SOLVAY and SOGEFI have teamed-up to produce the first Plastic Diesel Fuel Filter fully made of recycled polyamide 66, ready for mass-production. This has been achieved by using the brand new plastic compound developed by SOLVAY Engineering Plastics. This material is 100% recycled from airbag wastes, providing a premium material able to stand demanding applications requirements supplied through circular economy, which is quite unusual in automotive industry yet. SOGEFI has used this material through its existing plastic injection process, and tested the parts on extensive bench validation tests. It confirmed that this material is fully compatible with standard injection process, and that all the tests have been passed successfully. Finally, PSA Group has driven the choice of the tested parts: DV engine 1.6l Euro6b application, homologated the material grade and evaluated the whole validation process.
2017-03-28
Technical Paper
2017-01-1311
Suman Mishra, Nagesh Gummadi, Lloyd Bozzi, Neil Vaughn, Rob Higley
Abstract Air rush noise is exhaust gas driven flow-induced noise in the frequency range of 500-6500 Hz. It is essential to understand the flow physics of exhaust gases within the mufflers in order to identify any counter measures that can attenuate this error state. This study is aimed at predicting the flow physics and air rush noise of exhaust mufflers in the aforementioned frequency range at a typical exhaust flow rate and temperature. The study is performed on two different muffler designs which show a significant air rush noise level difference when tested on the vehicle. The transient computational study was performed using DES with 2nd order spatial discretization and 2nd order implicit scheme for temporal discretization in StarCCM+. To compare with test data, a special flow test stand is designed so that all high and low frequency contents emanating from the engine are attenuated before the flow enters the test part.
2017-03-28
Technical Paper
2017-01-1354
Timothy Morse, Michael Cundy, Harri Kytomaa
Abstract One potential fire ignition source in a motor vehicle is the hot surfaces on the engine exhaust system. These hot surfaces can come into contact with combustible and flammable liquids (such as engine oil, transmission fluid, brake fluid, gasoline, or Diesel fuel) due to a fluid leak, or during a vehicle collision. If the surface temperature is higher than the hot surface ignition temperature of the combustible or flammable liquid in a given geometry, a fire can potentially ignite and propagate. In addition to automotive fluids, another potential fuel in post-collision vehicle fires is grass, leaves, or other vegetation. Studies of hot surface ignition of dried vegetation have found that ignition depends on the type of vegetation, surface temperature, duration of contact, and ambient conditions such as temperature and wind speed. Ignition can occur at surface temperatures as low as 300 °C, if the vegetation is in contact with the surface for 10 minutes or longer.
2017-03-28
Technical Paper
2017-01-1089
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Abstract Exhaust Gas Recirculation (EGR) has been in use for many years to control NOx emissions in commercial vehicle applications. Emissions limits are tighter with every new regulation while durability requirements continue to increase, so EGR system manufacturers must be able to provide high performance and robust designs even with high thermal loads. The commercial vehicle market is characterized by lower production rates than passenger car programs and the same engine must cope with multiple applications that have totally different engine calibrations. In some cases it is necessary to design two or more EGR systems for an engine platform, with a consequential impact on cost and development timeline. The optimal design of an EGR system needs to take into consideration several topics related with performance and durability: efficiency and pressure drop, fouling, boiling, thermal fatigue, vibration, pressure fatigue and corrosion among others.
2017-03-28
Technical Paper
2017-01-0472
Gyoko Oh
Abstract To prevent corrosion of the inlet part with aqueous ammonia injection, high chromium corrosion-resistant materials have been applied for welded joints of mufflers. Bending fatigue strength of welded joint samples of flange pipes was defined through fatigue experiments, modeling that high fluctuating stresses exist in the inlet and outlet flange pipes of a muffler caused by the vibration of a moving vehicle. Factors that caused fatigue to failure such as welding bead shape and metallographic structure were identified through local stress measurements, FEM stress simulations, microscopic observations, and SEM-EDS composition analyses. By comparing with sample A having a smaller flank angle and sample B having a larger flank angle, the results suggested that the difference of bending fatigue strengths at 200,000 cycles was 24% when based on nominal stress, and the difference was 10% when based on measured maximum stress.
2017-03-28
Technical Paper
2017-01-1085
Todd Brewer, Cagri Sever, Ruichen Jin, Michael Herr, Xingfu Chen, Reda Adimi
Abstract In a separate SAE paper (Cylinder Head Design Process to Improve High Cycle Fatigue Performance), cylinder head high cycle fatigue (HCF) analysis approach and damage calculation method were developed and presented. In this paper, the HCF damage calculation method is used for risk assessment related to customer drive cycles. Cylinder head HCF damage is generated by repeated stress alternation under different engine operation conditions. The cylinder head high cycle fatigue CAE process can be used as a transfer function to translate engine operating conditions to cylinder head damage/life. There are many inputs, noises, and design parameters that contribute to the cylinder head HCF damage CAE transfer function such as cylinder pressure, component temperature, valve seat press fit, and cylinder head manufacturing method. Material properties and the variation in material properties are also important considerations in the CAE transfer function.
2017-03-28
Technical Paper
2017-01-1086
Cagri Sever, Todd Brewer, Scott Eeley, Xingfu Chen, Ruichen Jin, Emad Khalil, Michael Herr
Abstract For aluminum automotive cylinder head designs, one of the concerning failure mechanisms is thermo-mechanical fatigue from changes in engine operating conditions. After an engine is assembled, it goes through many different operating conditions such as cold start, through warm up, peak power, and intermediate cycles. Strain alternation from the variation in engine operation conditions change may cause thermo-mechanical fatigue (TMF) failure in combustion chamber and exhaust port. Cylinder heads having an integrated exhaust manifold are especially exposed to this failure mode due to the length and complexity of the exhaust gas passage. First a thermo-mechanical fatigue model is developed to simulate a known dynamometer/bench thermal cycle and the corresponding thermo-mechanical fatigue damage is quantified. Additionally, strain state of the cylinder head and its relation to thermo-mechanical fatigue are discussed. The bench test was used to verify the TMF analysis approach.
2017-03-28
Technical Paper
2017-01-1065
Douglas R. Martin, Benjamin Rocci
Abstract Exhaust temperature models are widely used in the automotive industry to estimate catalyst and exhaust gas temperatures and to protect the catalyst and other vehicle hardware against over-temperature conditions. Modeled exhaust temperatures rely on air, fuel, and spark measurements to make their estimate. Errors in any of these measurements can have a large impact on the accuracy of the model. Furthermore, air-fuel imbalances, air leaks, engine coolant temperature (ECT) or air charge temperature (ACT) inaccuracies, or any unforeseen source of heat entering the exhaust may have a large impact on the accuracy of the modeled estimate. Modern universal exhaust gas oxygen (UEGO) sensors have heaters with controllers to precisely regulate the oxygen sensing element temperature. These controllers are duty cycle based and supply more or less current to the heating element depending on the temperature of the surrounding exhaust gas.
2017-03-28
Technical Paper
2017-01-0965
Lorenzo Nocivelli, Gianluca Montenegro, Angelo Onorati, Francesco Curto, Panayotis Dimopoulos Eggenschwiler, Yujun Liao, Alexander Vogel
Abstract The application of liquid aqueous Urea Solution (AUS) as reductant in SCR exhaust after-treatment systems is now a commonly accepted industry standard. Unfortunately, less acceptable are the associated difficulties caused by incomplete decomposition of the liquid, resulting in solid deposits which accumulate in the exhaust pipe downstream of the dosing components. The correct prediction of the spray pattern and, therefore, the spray impact on the walls is a key feature for the system optimization. A mechanical patternator, designed on the basis of CFD performance assessment, involving a Lagrangian representation of the dispersed liquid fully coupled with a 3D Eulerian description of the carrier phase, has been built and used to measure the spray mass distribution.
2017-03-28
Technical Paper
2017-01-0964
Jakob Heide, Mikael Karlsson, Mireia Altimira
Abstract Selective Catalytic Reduction (SCR) of NOx through injection of Urea-Water-Solution (UWS) into the hot exhaust gas stream is an effective and extensively used strategy in internal combustion engines. Even though actual SCR systems have 95-96% de-NOx efficiency over test cycles, real driving emissions of NOx are a challenge, proving that there is room for improvement. The efficiency of the NOx conversion is highly dependent on the size of UWS droplets and their spatial distribution. These factors are, in turn, mainly determined by the spray characteristics and its interaction with the exhaust gas flow. The main purpose of this study is to numerically investigate the sensitivity to the modelling framework of the evaporation and mixing of the spray upstream of the catalyst. The dynamics of discrete droplets is handled through the Lagrangian Particle Tracking framework, with models that account for droplet breakup and coalescence, turbulence effects, and water evaporation.
2017-03-28
Technical Paper
2017-01-1000
Jong Lee, Yu Zhang, Tom Tzanetakis, Michael Traver, Melanie Moses-DeBusk, John Storey, William Partridge, Michael Lance
Abstract Greenhouse gas regulations and global economic growth are expected to drive a future demand shift towards diesel fuel in the transportation sector. This may create a market opportunity for cost-effective fuels in the light distillate range if they can be burned as efficiently and cleanly as diesel fuel. In this study, the emission performance of a low cetane number, low research octane number naphtha (CN 34, RON 56) was examined on a production 6-cylinder heavy-duty on-highway truck engine and aftertreatment system. Using only production hardware, both the engine-out and tailpipe emissions were examined during the heavy-duty emission testing cycles using naphtha and ultra-low-sulfur diesel (ULSD) fuels. Without any modifications to the hardware and software, the tailpipe emissions were comparable when using either naphtha or ULSD on the heavy duty test cycles.
Viewing 1 to 30 of 3850