Browse Topic: Spark ignition engines

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QA Test for CSP-7037053020245/15/2024
QA Test
Airlines Electronic Engineering Committee
testpreprint3SAE-PP-009974/27/2022
testpreprint3
Mutagaana, Festo
A Numerical Study on the Effect of a Pre-Chamber Initiated Turbulent Jet on Main Chamber Combustion2022-01-04693/29/2022
To elucidate the complex characteristics of pre-chamber combustion engines, the interaction of the hot gas jets initiated by an active narrow throated pre-chamber with lean premixed CH4/air in a heavy-duty engine was studied computationally. A twelve-hole KAUST proprietary pre-chamber geometry was investigated using CONVERGE software. The KAUST pre-chamber has an upper conical part with the spark plug, and fuel injector, followed by a straight narrow region called the throat and nozzles connecting the chambers. The simulations were run for an entire cycle, starting at the previous cycle's exhaust valve opening (EVO). The SAGE combustion model was used with the chemistry modeled using a reduced methane oxidation mechanism based on GRI Mech 3.0, which was validated against in-house OH chemiluminescence data from the optical engine experiments. Two different piston geometries, a flat piston geometry, and a more realistic bowl piston geometry were studied to understand the influence of jet on main chamber combustion. Varying the piston geometries results in different free jet times and hence main chamber combustion characteristics. Pre-chamber fuel ratio (PCFR) 6% of the total amount of fuel was investigated while keeping the global excess air ratios (λ) condition a constant value of 2.0. Both piston cases resulted in similar pre-chamber pressurization, with almost the same pre-chamber discharge and the equal pressure difference between pre-and main-chamber (ΔP) at the start of jet ejection. Different combustion behaviors were observed on analysis of the heat release rate in the main chamber. The importance of turbulence generated by the pre-chamber-initiated jets was further studied. It was observed that free jet time is a critical factor in developing turbulence in the main chamber. This increase in turbulence helps in increasing the burning velocity causing faster combustion. The influence of the jet-piston interaction is also analyzed as that determines the combustion behavior in the later CAD.
Sanal, Sangeeth, Echeverri Marquez, Manuel, Silva, Mickael, Cenker, Emre, Im, Hong G.
Test 123SAE-PP-005182/8/2022
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Basile, Julia, Mutagaana, Festo
Continuously Variable Displacement Drive for Engines Part 2, Design, Analysis, and TestSAE-PP-005162/8/2022
A new type of drive system has been designed, analyzed, patented, prototyped, and tested. The drive’s unique capabilities include the ability to vary the bottom dead center position to reduce the stroke, and simultaneously vary the top dead center position to achieve the desired compression ratio with one simple, low friction mechanism. The purpose of the concept is to reduce losses associated with operation at partial load as most engines spend a preponderance of their operating life at partial load. This paper covers the design and analysis, prototyping, and testing of the unit as an air compressor. Engine simulation of the unit configured as a gasoline engine showed a ~30% improvement in fuel economy on a 10-mode weighted cycle and is covered in SAE 2021-01-0442, “Continuously Variable Displacement Drive for Engines Part 1, Performance Simulation.”
Basile, Julia
Generating some more TasksSAE-PP-0049311/10/2021
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Kelly, Jason
Measurement of Light Vehicle Stationary Exhaust System Sound Level Engine Speed Sweep MethodJ1492_202110 (Historical)10/28/2021
This SAE Recommended Practice establishes the test procedure, environment, and instrumentation to be used for measuring the exterior exhaust sound level for passenger cars, multipurpose vehicles, and light trucks under stationary conditions providing a continuous measure of exhaust system sound level over a range of engine speeds. This document applies only to road vehicles equipped with an internal combustion engine. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. It is within the scope of this document to measure the stationary A-weighted sound pressure level during: Measurements at the manufacturing stage Measurements at official testing stations Measurements at roadside testing It does neither specify a method to check the exhaust sound pressure level when the engine is operated at realistic load nor a method to check the exhaust sound pressure levels against a general noise limit for categories of road vehicles. It provides the means for detecting exhaust system resonances with the potential to affect both exterior and interior sound quality. SAE J2805 provides methods to assess vehicle noise emission consistent with in-use vehicle noise emissions at realistic vehicle loads and speeds. This document incorporates certain provisions of ISO 5130:2019 for measuring the sound level of exhaust systems (see Appendix A).
Light Vehicle Exterior Sound Level Standards Committee
Engine Power Test Code - Engine Power and Torque CertificationJ2723_202110 (Current)10/15/2021
This document specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349 (Rev. 8/04) or the gross engine power of a production engine according to SAE J1995. Manufacturers who advertise their engine power and torque ratings as certified to SAE J1349 or SAE J1995 shall follow this procedure. Certification of engine power and torque to SAE J1349 or SAE J1995 is voluntary; however, this power certification process is mandatory for those advertising power ratings as “Certified to SAE J1349” or “Certified to SAE J1995.” In the event that an engine made by one manufacturer is sold to a consumer in a vehicle produced by a second manufacturer, engine certification may be completed by either manufacturer or by both manufacturers working together. An example of the latter would be the completion of witness testing by the engine manufacturer with the submission of certification documents by the vehicle manufacturer.
Engine Power Test Code Committee
confirmation testSAE-PP-004178/31/2021
confirmation test
SintzADMIN, Jeneane, SintzUSER, Jeneane, Mutagaana, Festo, Anthony, Lindsay, Mutagaana, Festo, SintzUSER, Jeneane
2 jms 8/27SAE-PP-004158/27/2021
2 jms 8/27 jeneane was here
SintzUSER, Jeneane, SintzADMIN, Jeneane
Regulated Intake Air Boosting and Engine Downspeeding as a Viable Solution for Performance Improvement and Emission Reduction of a Single-Cylinder Diesel Engine03-15-02-00098/16/2021
The present work proposes a viable approach to develop single-cylinder diesel engines for the future by implementing regulated intake air boosting (RIAB) and engine downspeeding (ED) along with the well-established low compression ratio (LCR) approach. The investigations were conducted in a mass-production light-duty single-cylinder diesel engine initially equipped with a naturally aspirated (NA) intake system. By lowering the compression ratio (CR) and implementing the intake air boosting (IAB) using a belt-driven supercharger, the maximum brake mean effective pressure (BMEP) of the engine could be increased by 50%. More importantly, the improved performance could be achieved without violating the peak firing pressure (PFP) limits. However, a significant penalty was observed in the brake-specific fuel consumption (BSFC) at low-load operating points due to the additional power consumption of the IAB system. Hence, RIAB was implemented to optimize the boost pressure with respect to engine load to simultaneously reduce the BSFC and oxides of nitrogen (NOx) and soot emissions. Further, the increased full-load performance of the engine was leveraged to implement the ED approach that could reduce the operating speeds of the engine by 37.8%. It was observed that the benefits of downspeeding a supercharged engine are significantly high due to the simultaneous reduction of the frictional losses of the base engine and the power consumption of the supercharger. Overall, by combining the above concepts and the proven LCR approach, significant benefits could be achieved in fuel economy and exhaust emissions that are quantified for the regulatory Modified Indian Drive Cycle (MIDC) using a one-dimensional tool. The obtained results show a net reduction of 77.8% and 39.5% in the soot and NOx emissions, respectively. Moreover, a significant benefit of 14.8% could be achieved in the fuel economy. Thus the proposed approach can be used to develop single-cylinder diesel engines for the future to improve vehicle performance and comply with stringent emission regulations.
Vikraman, V., Krishnasamy, Anand, Ramesh, A.
Knock: A Century of Research03-15-01-00047/28/2021
Knock is one of the main limitations on increasing spark-ignition (SI) engine efficiency. This has been known for at least 100 years, and it is still the case today. Knock occurs when conditions ahead of the flame front in an SI engine result in one or more autoignition events in the end gas. The autoignition reaction rate is typically much higher than that of the flame-front propagation. This may lead to the creation of pressure waves in the combustion chamber and, hence, an undesirable noise that gives knock its name. The resulting increased mechanical and thermal loading on engine components may eventually lead to engine failure. Reducing the compression ratio lowers end-gas temperatures and pressures, reducing end-gas reactivity and, hence, mitigating knock. However, this has a detrimental effect on engine efficiency. Automotive companies must significantly reduce their fleet carbon dioxide (CO2) values in the coming years to meet targets resulting from the 2015 Paris Agreement. One path towards meeting these is through partial or full electrification of the powertrain. However, the vast majority of automobiles in the near future will still feature a gasoline-fueled SI engine; hence, improvements in combustion engine efficiency remain fundamental. As knock has been a key limitation for so long, there is a huge amount of literature on the subject. A number of reviews on knock have already been published, including in recent years. These generally concentrate on current understanding and status. The present work, in contrast, aims to track the progress of research on knock from the 1920s right through to the present day. It is hoped that this can be a useful reference for new and existing researchers of the subject and give further weight to occasionally neglected historical activity, which can still provide important insights today.
Corrigan, Daire James, Fontanesi, Stefano
Vehicle OBD II Compliance Test CasesJ1699/3_202104 (Current)4/28/2021
The main purpose of this SAE Recommended Practice is to verify that vehicles are capable of communicating a minimum subset of information in accordance with the diagnostic test services specified in SAE J1979, or the equivalent document ISO 15031-5. Any software meeting these specifications will utilize the vehicle interface that is defined in SAE J2534. SAE J1699-3 tests shall be run using an SAE J2534-1 (API Version 04.04) Interface. However, the use of an SAE J2534-2 (API Version 04.04) Interface shall be permitted if the following conditions are met: The number of 29-bit ISO 15765 OBD ECUs exceeds the capability of the SAE J2534-1 Interface. The SAE J2534-2 Interface meets or exceeds all of the SAE J2534-1 requirements and also supports the SAE J2534-2 feature “Mixed Format Frames on a CAN Network.”
Vehicle E E System Diagnostic Standards Committee
Power and Torque Determination for UAS Engines Having Maximum Power Ratings at or Below 22.4 kWARP6971 (Current)4/7/2021
This recommended practice is applicable to reciprocating engines powering unmanned aerial vehicles (UAV) having rated power values less than 22.4 kW, and which are not to be used for human transport.
E-39 Unmanned Aircraft Propulsion Committee
Transformational Technologies Reshaping Transportation - An Industry PerspectiveSAE-PP-003372/26/2021
Freight trucking has always embraced continuous improvement although the general public may be largely unaware of the tremendous changes that have occurred to date in vehicle safety, efficiencies, emissions mitigation and asset utilization. Today’s freight industry is in the early stages of dramatic technological advances in areas such as connectivity, automation and electrification. Fleet and manufacturer perspective on these transformational technologies are universally supportive, driven both by economic and regulatory factors. The early stages of these technological revolutions are characterized by a multitude of competing concepts confusing choices, complicated by a significant number of competing vested interests obscuring objectivity, and clouded by billions of dollars of venture capital. The objective of this report is to provide unbiased insight into the freight industry’s thoughts on these transformational technologies.
Mutagaana, Festo, SintzUSER, Jeneane
A New Image De-hazing Method for Safety Critical ADAS ApplicationsSAE-PP-003122/19/2021
Driver safety and Advanced Driver Assistance Systems (ADAS) is gaining lot of importance these days. In some countries, there are strict regulations in place which mandate the use of certain ADAS features in automobiles. However, as the need for these safety critical systems increases, the challenges associated also increase. These challenges can arise due to technology, human factors or due to nature. In countries like India, where one can expect different weather conditions with changing geography, the associated challenges are mainly due to the natural factors like haze, fog, rain and smoke. This poses a challenging problem in terms of visibility for the drivers as well as in vision based ADAS; thereby, leading to many fatal road accidents. In this paper, a novel pre-processing technique, which addresses the interesting problem of enhancing the perceptual visibility of an image that is degraded by atmospheric haze, is proposed. The solution to this problem is presented by combining model (Beer Lambert model) based and non-model based technique of haze removal. The combined hybrid model picks the best haze free image from the series of non-hazy outputs, that are derived based on multiple scattering coefficients of the input hazy image. The idea here is to restore the true color of an image that is affected by the atmospheric haze. In comparison with the state of the art methods that are available in literature, the proposed method is shown to be capable of recovering better haze-free images both in terms of visual perception and quantitative evaluation. The proposed method promises better perceptual understandings and visibility restoration for vision based ADAS under hazy driving conditions.
Mutagaana, Festo, SintzUSER, Jeneane
7.0.102 - Prescriptive Modeling, Simulation and Performance Analysis of Mild Hybrid Vehicle and Component OptimizationSAE-PP-002782/4/2021
Reckoning today's environmental rules, legislative regulation and market requirements- the automotive industry of late has witnessed an increased vigor and enthusiasm by auto makers towards electrification of vehicles across all platforms in a bid to improve fuel economy and performance. Hybridization of a vehicle often involves the use of expensive high performance motors and large battery packs. However due to the challenges associated with the packaging of bulky battery and motor systems in existing drive train, mild hybrid systems have been preferred over strong or full hybrids especially in current production models as they don't entail any major change in architecture and the reduced battery size, both of which provide for easier packaging of components. In this paper the authors present a generic model of a mild hybrid vehicle that can be effectively used to simulate any vehicle, enabled with a mild hybrid system to predict with approximate certainty the improvement in performance parameters and optimize component size. Thus, assist in selection and sizing of motor, battery and the associated operation voltage, with minimal monetary expense and time consumption. Consequently, an optimal system configuration for the prototype build is arrived while resulting in significant cost and time savings.
Lname, Fname
6.0.117 - Definition of a Protocol of Automatic Identification and Notification of Road Accidents and Development of an Advanced eCall SystemSAE-PP-002722/4/2021
The eNOTIFY project defined an algorithm which allows the vehicle to recognize when an accident has occurred and what kind of accident has taken place (frontal, side, roll-over or rear-end collision). The innovative aspects of this methodology are basically that, for each type of accident and for each class of vehicle, a maximum and minimum level of vehicle accelerations (linear or angular) are defined for the severe accident, slight accident and no accident scenarios. A direct application of this algorithm could be to include it in an on-board unit on vehicles, and use it in emergency call applications. eCall devices have been developed to automatically notify emergency services in the event of an accident, in which a fast and efficient rescue operation can significantly increase the chances of survival of the severely injured. In order to reduce response time and improve the efficiency of the medical and technical services, fast and accurate accident identification is required. This on-board algorithm makes it possible to identify the type and severity of the accident allowing emergency services to respond accordingly; and as such could contribute to saving lives.
Mutagaana, Festo
6.0.112 - Emission Optimization Approach to Meet the Current Indian Emission Norm Without EGR Cooling for a Vehicle Equipped with Common Rail Diesel EngineSAE-PP-002682/4/2021
In India, diesel engine powered vehicles are finding rising demand due to the subsidy offered on diesel. Currently, BS-IV emission norm (equivalent to E-IV in Europe) is in existence. To meet this emission norm, OEM look for improved engine design, use of common rail injection system, advanced after treatment. In the current article, a methodology is demonstrated by which the required emissions on multipurpose vehicle (MPV) powered with 2.2L common rail injection system was met with no need of EGR cooling. This was achieved by identifying the operating points from the BS-IV emission cycle where EGR cooling is beneficial. The next step involves assessing the loss of function due to its removal. The final step involves strategies which can bring the original optimized value of NOx-PM. Removal of EGR cooling avoids the cooling of intake charge and reduces the HC and CO emission. Also, it gets rid of complication in the under bonnet packaging and leads to maintenance free operation. This resulted in overall reduction of the precious metal loading on the catalytic convertor by 50% from its value in the production. Thus, the overall cost saving of 3.5% of the total engine cost was achieved without losing the functional requirement.
Mutagaana, Festo
6.0.107 - A Unified Approach for Prediction and Control of Motorcycle Vibration Subjected to Engine Dynamic ForceSAE-PP-002632/4/2021
In this paper the approach to predict vibrations in motorcycles is presented. It can be divided mainly in two parts: prediction of engine forces using multi body dynamics (MBD) simulation and prediction of vibration response using FEA. Dynamic forces predicted at each engine mount through MBD simulation are used as input to FE analysis for vibration prediction. Single cylinder SI engine having primary balancer shaft is considered to develop this methodology. Flexibilities of important parts are considered for MBD simulation. Crankshaft ball bearing which is used in almost all two wheeler engine is modeled with 6×6 stiffness matrix. It provides coupling between radial, axial and tilting deflections of bearing and it also allows moment transfer from crankshaft to casing. This helps to predict realistic forces at each bearing and engine mounts. Distribution of primary and secondary forces at crank bearings and at different engine mounts is studied. Forces predicted from MBD simulation at each engine mounts are applied to full vehicle FE model. Forced response is predicted at each TSP and compared with test response at same point. It was found that predicted response was in well agreement with test response. Based on understanding of distribution of forces it is decided to increase mount stiffness of the support experiencing more force. This in turn helped to reduce vibration at TSP. This approach is effective to predict vibrations in early design stage to reduce development cost and time.
Mutagaana, Festo
6.0.102 - FeSnSAE-PP-002582/4/2021
The aim of this study is to develop the simple approach to produce iron-tin (Fe-Sn) intermetallic compound for EV battery anode materials. Intermetallic FeSn2 compound was synthesized by two step method. Mechanical alloying of Fe and Sn element powders with equal atomic ratio was performed for 25 h. The mechanically alloyed powders compacts were processed via liquid phase sintering, in which the powders compacts were heated at different temperatures and for 10 min. The experimental materials were characterized by X-ray diffraction, scanning electron microscopy and thermal analysis techniques. The FeSn2 compound was formed during liquid phase sintering. However, the reaction between Fe and Sn was incomplete under the investigated sintering time of 10 min.
Mutagaana, Festo
Near-TDC flow field analysis in a high-tumble production SI engine using endoscopic high-speed Particle Image Velocimetry (eHS-PIV)SAE-PP-002512/3/2021
The latest generation spark-ignition (SI) engines implement high tumble flow design to achieve unprecedented high brake thermal efficiency of over 40%, which will continue to play an important role in both conventional and electrified future vehicles. To maximise the potential of high-tumble SI engines, there is a clear need for in-cylinder flow and flame analysis conducted timely in a realistic environment. For the first time, this study meets this need by performing innovative endoscopic imaging of flow fields and flame inside the cylinder of a selected production engine using a particle image velocimetry (PIV) laser and high-speed camera system operated at 35 kHz. Through this timeresolved, two-dimensional measurement of the realistic in-cylinder phenomenon, many new findings have been achieved. Regarding the tumble vortex, its centre is seen more shifted to the exhaust valve side, which is related to an asymmetric, “surging” flow structure formed during the upward motion of the piston in the compression stroke. When the piston approaches towards the top dead centre, the tumble centre is not clearly defined anymore, but a new lateral exhaust-to-intake flow forms as the surging flow bounces back off the exhaust valve side of the pent-roof. This wallguided “bounce-back” flow does not form when the intake valve closure is retarded for the realisation of Atkinson Cycle and thus the surging flow is reduced and peaks at later timing. The new in-cylinder flow structures observed from the high-tumble engine directly impact the flame development. From the high-speed natural combustion luminosity imaging performed using the same camera endoscope, the flame centroid is found to shift towards the intake valve side, which is consistent with the bounce-back flow direction at the advanced intake valve closure timing.
Anthony, Lindsay
Effect of Real-World Driving and Drive Modes on Electric Vehicle Energy Consumption and Performance in a Tier-II Indian CitySAE-PP-002502/3/2021
Electric vehicles (EVs) are tested for their driving performance, energy consumption (EC), and electric range in a chassis dynamometer laboratory as per the test procedure of the Automotive Industry Standards (AIS) in India. However, a laboratory test is different from the real-world test. In this study, the test vehicle is an experimental EV conversion car developed for the study. The EV uses a prototype conversion kit consisting of an indigenously built 3-phase induction motor and Li-ion battery pack. The study reports a detailed discussion on the real-world as well as laboratory tests conducted for the EV. It provides an intuition of the real-world tests conducted on the selected traffic routes of a Tier-II Indian city (Dehradun city) using a data logger with multiple sensors. It investigates the effect of real-world driving and different drive-modes (idling, acceleration, deceleration, and cruising) on the EC and performance of the EV. The real-world tests follow the car-chasing technique. The study shows that the average real-world EC of all-route is 145.83Wh/ km, and laboratory EC is 88.10 Wh/km. It reveals that the average real-world EC is higher than the laboratory baseline data by 41.97%, 65.40%, 89.39% on the congested, medium, and low traffic routes respectively. It also performs the analysis of percentage contribution of the drive-modes to the load current, EC, and input power using the road cycle and driving cycle analysis. This study is a novel attempt to understand and determine the EC, usability, and performance of the EV in real-world conditions on the Tier-II city roads for achieving a better driving range. It attempts to find out the energy-efficient route, the gap between the real-world EC data, and the reference laboratory data. The study highlights the importance of addressing real-world features in reviewing and improving the dynamometer cycle and future EC regulations for EVs.
Anthony, Lindsay
6.0.113 - Measuring Smoke Emissions from Different Generations Diesel Passenger Cars in Antwerp-Belgium During Winter and SpringSAE-PP-002442/3/2021
More than 600 passenger cars were measured during winter and spring at the end of 2012 beginning 2013 in Antwerp Belgium in order to determine the effect of mileage and year of first registration on smoke emissions or smoke opacity from diesel light duty vehicles. All measurements were contacted in two different campuses of the University of Antwerp and under different ambient conditions. Various parameters such as ambient temperature, ambient humidity, car age, number of passengers in each cars, time of measurement etc. were taken into account and presented in this paper. All findings from these set of measurements were split into two big categories, those cars with less than 150,000km on the clock and the second one with those cars with higher number of mileage. The effect of ambient temperature but also the mileage on smoke opacity will be presented and discussed in more details. Smoke emissions are dependent also on ambient humidity and in this study will be considered the important role that humidity plays in total smoke opacity from various diesel engines. Finally the effect of mileage on smoke opacity is something that will be also examined and discussed intensively. Last but not least, a comparison between two similar cars equipped with the same engine in terms of capacity but fitted with standard and tuned electronic control unit (ECU) respectively was done and interesting findings will be shown in this work.
Mutagaana, Festo
Knock detection method for dual-fuel compression ignition engines based on block vibration analysisSAE-PP-002372/3/2021
A new knock detection method based on block vibration analysis, specially developed for dual-fuel compression ignition engines, is presented in this work. Experimental tests were carried out in a four-cylinder compression ignition engine at full and 60% of load, running at 2000, 2500, and 3200 rpm with different amounts of hydrogen and liquefied petroleum gas injected in the air inlet hose. Fuel flow was increased in approximately 10% energy share steps until knock was detected for both fuels. The maximum substitutions at full and 60% of load were 38%, 54% for hydrogen, and 57%, 63% for liquefied petroleum gas, respectively. The component of the block vibration signal that is sensitive to knock was determined by studying the block's resonant frequency, the influence of valve closing impacts, and comparing the block vibration recorded with knocking and non-knocking combustion. To quantify the knock intensity of a combustion cycle, four fast-computing metrics were tested selecting the maximum amplitude of filtered vibration for knock detection since it was the least sensitive to crankshaft speed. Two knock indexes for knock evaluation were compared, concluding that the pondered deviation from the reference index, proposed in this work, has a better performance. The knock threshold was achieved when the knock index was greater than 5 regardless of the substitute fuel, crankshaft speed, and engine load. Finally, the method was optimized for real-time knock detection.
Anthony, Lindsay
2.0.105 - Piston Sealing System Structure Design for Automobile's Lightweight Auto-TransmissionSAE-PP-002152/1/2021
Current automobile's auto-transmission has problems of defects and cost reduction because of welding process and very complicated assembly process due to individualized transmission piston and sealing components. Also, size and heavy weight of transmission piston components are the source of low mileage because they are made of aluminum, steel material. In this study, therefore, we perform structure design for piston sealing system which integrates piston and sealing material for automobile's lightweight auto-transmission. Also performed stress analysis through finite element analysis to secure required suitable strength when internal pressure is applied after assemble.
Mutagaana, Festo
2.0.103 - Driver Behavior Detection based On PPP-GNSS TechnologySAE-PP-002132/1/2021
Driver behavior is one of the most important factors in safe mobility. In general, various driver maneuvers can be determined from acceleration of the vehicle. Physically, the acceleration and brake can be detected with longitudinal acceleration while turning and lane change can be detected with lateral acceleration. Normally, IMU (inertia measurement unit) has been designated to get these data. However, the IMU is not convenience to install in the vehicles especially as aftermarket parts. Nowadays, navigation system technologies have been much improved, both on availability and accuracy with combination of multiple navigation satellite systems. Normally, it's called Multi-GNSS (multiple global navigation satellite system). In particular, the satellite navigation systems available in this work are GPS, GLONASS, and QZSS. With decimeter precision and the update rate scale up to 10-Hz, the GNSS can be a viable alternative for driver behavior detection. In previous studies, it was found that dangerous behaviors such as aggressive lane change required decimeter accuracy from GNSS. Consequently, in this article, the PPP (Precise Point Positioning) technique was applied to develop a behavior detection system. Vehicle maneuvers such as cornering and lane change detected by IMU and Multi-GNSS were collected and compared. The JAVAD Delta TRE_G3TH experimental Multi-GNSS receiver installed on a utility vehicle was used in this work. The navigation data were post-processed with the open source RTKLIB software. On the other hand, the reference vehicle dynamic measurement system was VBOX 3LSi with integrated IMU. A simple curvature model was proposed and applied to estimate the lateral acceleration. In conclusion, experimental results show that driver behavior detection is feasible with the Multi-GNSS PPP. The results revealed that with PPP solution the estimated lateral acceleration could be manipulated within 10% deviation.
Mutagaana, Festo
2.0.102 - Model Based System Design of Urban Fleet Electric Vehicle ConversionSAE-PP-002122/1/2021
To reduce such pollution in the city area, zero emission fleet vehicles can be employed for a short distance goods transport. In current development, old pickup trucks are targeted as the vehicle to be converted to an electric vehicle. In this case, model based system design were employed to reduce the design cost and process time. Vehicle specification and the Modified and Simplified Federal Urban Driving (MSFUD) cycles were used as inputs to the MATLAB scripted program represented the models of EV components and the power flow in the system. Lithium Ion batteries and Hydrogen fuel cell system were also employed as the power sources for the electric propulsion. The simulation shows different scenarios that could be used as the decision making support information and EV design exploration. It can predict several various EV and fuel cell characteristics, such as driving range, performance, torque speed map, and motor power dynamics. The simulation study has shown, by comparison, employing fuel cell as the power sources will improve electric vehicle conversion of the pickup truck in terms of both performance and range in the long run.
Mutagaana, Festo
062 - An Investigation on the Auto-Ignition of Fuel-Air Mixture Induced by Release of Oil-Fuel Droplets from Cylinder-Liner Using Multi-Zone ModelSAE-PP-002011/30/2021
This study investigated effects of gas inhomogeneity induced by droplets of fuels and oils on the auto ignition timing and temperature in the direct-injection spark ignition (DISI) engine by means of detailed numerical calculation using multi zone model. Recent researchers pointed out that droplets are made of fuels and oils which mix on the cylinder liner and released from the cylinder liner [1]. During the compression stroke released droplets reach the auto ignition temperature before flame propagation induced by spark ignition. It is called Pre-ignition. In combustion chamber, there is inhomogeneity caused by temperature and mixture distribution. In this study, the effects of gas inhomogeneity produced by droplet on the auto ignition timing and temperature have been investigated using Multi-Zone model of CHEMKIN-PRO by changing initial temperature and initial equivalence ratio. Especially, the volume of first ignition zone is focused on. As for fuels, this study used n-heptane to observe the impacts which the gas inhomogeneity has on low-temperature heat release (LTHR). As for calculation conditions, 15 zones model were assumed. Based on the assumption that the volume of the droplets from cylinder-liner is not always constant, ignition delay time and ignition temperature of mixture were confirmed, changing the volume of first ignition zone. Consequently, we found that the volume of first ignition zone affects the auto-ignition of air-fuel mixture and there is possibility to lead to cause Pre-ignition.
Mutagaana, Festo
058 - Steering Effort Reduction by DC Motor Assisted Steering Mechanism in 3- Wheeler VehicleSAE-PP-001961/30/2021
The steering system of a 3-wheeler vehicle comprises a single column steering tube. The steering inclination at handle bar end is converted to wheel slip or inclination by the steering column. A compromise in either ride or handling is considered in the functional requirement of the 3-wheeler vehicle. The 3- wheeler vehicle under study is designed for ride comfort and the handling levels are compromised. Variants of the vehicle under study are meant for public passenger transport requirements. Drivers' ride comfort is considered as the primary functional requirement during design and driver's steering fatigue is not given importance. For the comfort of driver, steering effort has to be less without compromise in handling characteristics. The driver of this type of vehicle drives the vehicle for 15-18 hours a day. Driver's feedback suggests high steering effort as a human fatigue failure mode and also a cause of shoulder pain. In the present work, a DC motor assisted steering mechanism with an electronic control module has been designed. This improves the handling of the vehicle and reduces the static steering effort. Steering effort of the vehicle is experimentally determined in a test track for static maneuvering conditions. A look up table reference is used for programming the control module and to control the DC motor for various operating steering angle. The tests are also carried out in driver alone and gross vehicle weight conditions. The test results suggest reduce of steering effort levels for the vehicle studied.
Mutagaana, Festo
Ignition System Measurements ProcedureJ973_202011 (Historical)11/3/2020
This SAE Recommended Practice specifies the design and/or evaluation with the specific equipment, conditions, and methods for distributorless battery ignition systems intended for use in various internal combustion engines including automotive, marine, motorcycle, and utility engine applications. The test procedures listed in this document are limited to measurements performed on a test bench only and do not include measurements made directly on engines or vehicles. This standard is not intended to supply information for battery ignition systems used in aircraft applications of any type.
Ignition Standards Committee
Lubricating Oil, Aircraft Piston Engine (Ashless Dispersant)J1899_202010 (Current)10/28/2020
This SAE Standard establishes the requirements for lubricating oils containing ashless dispersant additives to be used in four-stroke cycle, reciprocating piston aircraft engines. This document covers the same lubricating oil requirements as the former military specification MIL-L-22851. Users should consult their airframe or engine manufacturers manuals for the latest listing of acceptable lubricants.
E-38 Aviation Piston Engine Fuels and Lubricants
Lubricating Oils, Aircraft Piston Engine (Non-Dispersant Mineral Oil)J1966_202010 (Current)10/28/2020
This SAE Standard establishes the requirements for nondispersant, mineral lubricating oils to be used in four-stroke cycle piston aircraft engines. This document covers the same lubricating oil requirements as the former military specification MIL-L-6082. Users should consult their airframe or engine manufacturers manuals for the latest listing of acceptable lubricants.
E-38 Aviation Piston Engine Fuels and Lubricants
Endurance Optimization of a Tandem Helicopter with Variable Speed Rotors and a Spark-Ignition EngineF-0076-2020-1631510/5/2020
Rotary unmanned aerial vehicles (R-UAV) are becoming commonplace as a solution for maritime surveillance activities due to their vertical take-off and landing (VTOL) capability. Extending flight duration is thus crucial; one approach is to slow down the rotors in flight, which improves their efficiency. An in-house tandem rotorcraft performance model is used to evaluate the benefits of slowed rotors in endurance flight when used in conjunction with a spark-ignition engine. The performance model is validated using experimental data from flight tests in hover and lowspeed flight. A surrogate-based optimization approach determines the flight and engine speeds required for minimal fuel consumption throughout a typical endurance mission. Payload-Endurance and Payload-Range curves for flights at various payload and fuel capacities show overall benefits. Gains up to 25% and 15% in endurance are possible for f lights at standard and maximum fuel capacity. Range is not impacted negatively and sees gains at maximum fuel capacity. The spark-ignition engine plays a beneficial role as it contributes up to 38% of fuel burn reduction.
Bouchard, Mathieu, Laflamme, David, Rancourt, David, Laflamme, Enrick
Fuels in Ground Support Equipment (Other Than Gasoline or Diesel)AIR5373A (Current)9/23/2020
This SAE Aerospace Information Report (AIR) is intended as a source of comparative information and is subject to change to keep pace with experience and technical advances. This document describes currently used fuels and fuels which may be used in the future. Conventional gasoline and diesel fuels are intentionally omitted from this document.
AGE-3 Aircraft Ground Support Equipment Committee
Review of Additive Manufacturing for Internal Combustion Engine Components03-13-05-00399/9/2020
With highway vehicles using over 20% of the total energy consumption in the United States, making strides in improving their fuel economy will positively influence the nation’s environmental impact. One methodology to accomplish this outcome is by reducing vehicle weight. In this regard, since the internal combustion (IC) engine is a major contributor to the mass of an automobile, it is an ideal area to target. Prior efforts in this area include using alternative materials (e.g., aluminum or magnesium) to decrease weight. Here, additive manufacturing (AM) is an appealing option due to its freedom from typical manufacturing constraints and the ability to produce highly optimized designs using nonconventional powertrain materials (e.g., titanium). The use of AM has the potential to increase reliability, improve performance, decrease production cost, and possibly minimize the number of parts. Since metal-based AM is a relatively new area of manufacturing for IC engines, its use has been largely limited to research, motorsport, and luxury vehicle activities. Given its potential, this effort provides a review and summary of AM work completed in this field including design optimization, prototyping, tooling and indirect manufacturing, part production, and remanufacturing and repair for IC engine components.
Gray, Jamee, Depcik, Christopher
The Effect of Engine Speed, Exhaust Gas Recirculation, and Compression Ratio on Isobaric Combustion03-13-05-00388/14/2020
The present study evaluates the effect of engine speed, exhaust gas recirculation (EGR), and compression ratio on conventional diesel combustion (CDC) and two isobaric combustion cases, by utilizing multiple injection strategies. The experiments were conducted in a Volvo D13C500 single-cylinder, heavy-duty engine, fuelled with standard European Union (EU) diesel fuel. The engine was operated at three different speeds of 1200, 1500, and 1800 revolutions per minute (rpm). For each engine speed and combustion cases, the EGR rate was varied from 0% to 40%. The low-pressure isobaric combustion (IsoL) and high-pressure isobaric combustion (IsoH) were maintained at peak cylinder pressure (PCP) of 50 and 68 bar, respectively, which was representative of the peak motoring pressure (PMP) and PCP of CDC. This was possible by adjusting the intake air pressure to 1.7 and 2.3 bar—absolute for IsoL and IsoH, respectively, at 1200 rpm. At a higher engine speed, the intake air pressure was further increased to maintain top dead center (TDC) pressure. Irrespective of engine speed and EGR rates, it was found that IsoH has similar or higher gross indicated efficiency than CDC with the lowest efficiency for IsoL. The heat transfer losses were lower while the exhaust losses were higher for isobaric cases, compared to CDC. The heat transfer losses were further reduced due to limited time availability at higher engine speeds with a penalty in higher exhaust losses for all combustion cases. This additional exhaust energy would not be totally lost as it can be converted into useful work using an expander cylinder of the double compression expansion engine (DCEE) concept. At a given engine speed, higher EGR rates resulted in higher carbon monoxide (CO)/unburnt hydrocarbon (UHC)/soot emissions with lower nitrogen oxides (NOx) emissions. However, with increased engine speed, CO and UHC emissions were highly unchanged. A typical soot-NOx trade-off characteristic can be seen with increased soot and reduced NOx emissions, largely due to reduced charge premixing time at higher engine speed. From the compression ratio comparison results, it was found that a lower compression ratio resulted in reduced gross indicated efficiency and increased exhaust losses. Compared to the higher compression ratio, the lower compression ratio also led to lower heat transfer losses due to reduced combustion temperature. Besides, the NOx emissions were reduced with increased soot concentration at the lower compression ratio.
Goyal, Harsh, Dyuisenakhmetov, Aibolat, Houidi, Moez Ben, Johansson, Bengt, Badra, Jihad, Cenker, Emre, Chang, Junseok
Engine Oil Performance and Engine Service Classification (Other than “Energy Conserving” or “Resource Conserving”)J183_202007 (Current)7/29/2020
This SAE Standard outlines the engine oil performance categories and classifications developed through the efforts of the Alliance of Automobile Manufacturers (Alliance), American Petroleum Institute (API), the American Society for Testing and Materials (ASTM), the Engine Manufacturers Association (EMA), the International Lubricant Specification Advisory Committee (ILSAC), and SAE. The verbal descriptions by API and ASTM, along with prescribed test methods and limits, are shown for active categories in Table 1 and obsolete categories in Table A1. Appendix A is thus a historical documentation of the obsolete categories. For purposes of this document, active categories are defined as those (a) for which the required test equipment and test support materials, including reference engine oils and reference fuels, are readily available, or for which the Category Life Oversight Group has established equivalencies between unavailable tests and newer, available tests; (b) which ASTM or the test developer monitors precision for all tests; and (c) which are available for licensing by API EOLCS at time of writing. The current processes for initiating new classifications were developed through the cooperative efforts of the Alliance, API, ASTM, EMA, ILSAC, and SAE. New ILSAC classifications are developed using the procedure defined in API 1509 Annex C. New API “C” categories are added using the procedure defined in API 1509 Annex D. New API “S” categories are added by the API Lubricants Group.
Fuels and Lubricants TC 1 Engine Lubrication
Sound Levels for MotorcyclesJ331_202007 (Current)7/17/2020
This SAE Recommended Practice establishes the test procedure, environment, and instrumentation for determining the sound levels of motorcycles under full throttle acceleration and closed throttle deceleration.
Motorcycle Technical Steering Committee
Marine Stern Drive and Inboard Spark-Ignition Engine On-Board Diagnostics Implementation GuideJ1939-5_202006 (Current)6/30/2020
This document describes the application of the SAE J1939 recommended practices for compliance with on-board diagnostic malfunction detection system requirements for marine sterndrive and inboard spark ignition engines, as mandated by the California Air Resources Board (CARB). These Otto-cycle engines are not derived from automotive diesel-cycle engines.
Truck Bus Control and Communications Network Committee
Maximum Sound Level Potential for MotorcyclesJ47_202006 (Current)6/5/2020
This SAE Recommended Practice establishes the test procedure, environment, and instrumentation for determining the maximum sound level potential for motorcycles under wide open throttle acceleration and closed throttle deceleration.
Motorcycle Technical Steering Committee
A New Cavitation Algorithm to Support the Interpretation of LIF Measurements of Piston Rings2020-01-10914/14/2020
Laser induced fluorescence (LIF) is used to investigate oil transport mechanisms under real engine conditions. The engine oil is mixed with a dye that can be induced by a laser. The emitted light intensity from the dye correlates with the residual oil at the sensor position and the resulting oil film thicknesses can be precisely determined for each crank angle. However, the general expectation is not always achieved, e.g. an exact representation of piston ring barrel shapes. In order to investigate the responsible lubrication effects of this behavior, a new cavitation algorithm for the Reynolds equation has been developed. The solution retains the mass conservation and does not use any switch function in its mathematical approach. In contrast to common approaches, no vapor-liquid ratio is used, but one or several bigger bubbles are approximated, as have been observed in other experiments already. As a result, not only the known boundary conditions for the Reynolds equation become unnecessary, but the solution also gives a clearer idea as to the shape of the cavitation bubble. The combination of simulated oil film thicknesses, the resulting cavitation bubbles and the fixed field of view from the LIF sensor allows a reproduction of the measurement signal. The comparison of measurement and simulation exhibits a high correlation, and thus enables a deeper knowledge and understanding of the real conditions inside a combustion engine. On the other hand, it can be seen that effects such as a decrease in the LIF signal in the cavitation area is much lower than would be expected according to the literature.
Ruch, Fabian H., Wachtmeister, Georg
Non-Contacting Finger Seal Piston for Oil Less Engines2020-01-10964/14/2020
The current quest to reduce CO2 emissions combined to new technologies has sparked an interest in revisiting radically different engine configuration concepts, such as adiabatic and split-cycle engines. To achieve the full potential of both concepts, the combustion chamber must be sealed without lubricating oil. A promising approach that has yet remained elusive, is to lubricate the piston-liner interface with gases. This paper explores the concept of using non-contacting finger seals to seal piston engines combustion chambers. The finger seals, made of a gas-lubricated pad at the end of a flexible beam, are fixed on a rotating piston that uses the centrifugal force to close the piston-liner gap. A physics-based fluid-structure model is developed to predict finger displacements and sealing performances. The model shows that the radial displacement of the fingers naturally creates a convergent profile with the liner that generates sufficient aerodynamic pressure to maintain a micrometer gap that prevents the piston to contact the liner. The results also show that the achievable leakage area would be similar to that of Wankel rotary engine and friction losses would be negligible compared to those of conventional piston rings. On the other hand, the study reveals challenges that will need to be addressed in order that finger seals be practical in engines, such as the finger torsion, dynamic behavior when exposed to bore distortion as well as the manufacturing tolerances required to ensure contact-free operation.
Boudreau, Pascal, Picard, Mathieu
Further Experiments on the Effect of Bulk In-Cylinder Temperature in the Pressurized Motoring Setup Using Argon Mixtures2020-01-10634/14/2020
Mechanical friction and heat transfer in internal combustion engines have long been studied through both experimental and numerical simulation. This publication presents a continuation study on a Pressurized Motoring setup, which was presented in SAE paper 2018-01-0121 and found to offer robust measurements at relatively low investment and running cost. Apart from the limitation that the peak in-cylinder pressure occurs around 1 DegCA BTDC, the pressurized motoring method is often criticized on the fact that the gas temperatures in motoring are much lower than that in fired engines, hence might reflect in a different FMEP measurement. In the work presented in SAE paper 2019-01-0930, Argon was used as the pressurization gas due to its high ratio of specific heats. This allowed to achieve higher peak in-cylinder temperatures which close further the gap between fired and motored mechanical friction tests. In 2019-24-0141, Argon was mixed in different proportions with Air to synthesize gases with different ratios of specific heats in the aim of observing any abrupt transitions in the FMEP with different peak in-cylinder temperatures. In this publication, a higher loading test matrix to that published in 2019-24-0141 is presented, with an engine speed ranging from 1400 rpm to 3000 rpm and ratios of specific heats varying from that of Air (γ = 1.4) to that of Argon (γ = 1.67). The peak in-cylinder pressure was kept at a constant 103 bar. Results obtained in this work strengthen further the observations made in 2019-24-0141; where the measured FMEP is found to be insensitive to the different peak in-cylinder temperatures. In this study, a fast-response thermocouple of the eroding type was also fitted in the combustion chamber and gas-wall interface temperature histories were recorded. The transient heat flux was also computed through a spectral analysis and reported in this publication.
Caruana, Carl, Farrugia, Mario, Sammut, Gilbert, Pipitone, Emiliano
Impact of Spark Plasma Length on Flame Kernel Development under Flow Condition2020-01-11144/14/2020
Advanced ignition systems with enhanced discharge current have been extensively investigated in research, since they are highly regarded as having the potential to overcome challenges that arise when spark-ignition engines are running under lean or EGR diluted conditions. Local flow field is also of particular importance to improve the ignitability of the air-fuel mixture in SI engines as the spark plasma channel can be stretched by the flow across the spark gap, leading to longer plasma length, thus more thermal spark energy distributed to the air-fuel mixture in the vicinity of the spark plug. Research results have shown that a constantly high discharge current is effective to maintain a stable spark plasma channel with less restrikes and longer plasma holding period. However, with the further increase in discharge current, plasma channel becomes thicker, and the stretched plasma length becomes shorter under a constant flow speed, which may suppress the advantages of the enhanced discharge current. In this work, the interaction between discharge current level and plasma length under flow conditions is investigated. Whether a thick but shorter plasma channel or a thin but stretched farther plasma channel is more effective for the flame kernel formation is discussed to provide an insight into the influence of the plasma length on flame initiation. An optical combustion chamber platform along with a cross-flow generation system was used to study the plasma channel behavior; an in-house developed spark energy management module was employed to boost the discharge current level up to 3 A; in order to decouple the effect of discharge duration on flame initiation, the total discharge process was controlled within 0.8 ms.
Zhu, Hua, Tan, Qingyuan, Yu, Xiao, Yang, Zhenyi, Liang, Li, Zheng, Ming, Reader, Graham, Qian, Jin
Pre-design Investigation of Resonant Frequency Effects on Gas Exchange Efficiencies of a One-kW Natural-Gas Linear Engine Alternator2020-01-04884/14/2020
Performance of a natural gas two-stroke engine incorporated in a 1-kW free-piston oscillating Linear Engine Alternator (LEA) - a household electricity generator - was investigated under different resonant frequencies for pre-design phase purposes. To increase the robustness, power density, and thermal efficiencies, the crank mechanism in free-piston LEA is omitted and all moving parts of the generator operate at a fixed resonant frequency. Flexure springs are the main source of the LEA’s stiffness and the mass-spring dynamics dominates the engine’s speed. The trade-off between the engine’s performance, mass-spring system limits, and power and efficiency targets versus the LEA speed is very crucial and demands a careful investigation specifically at the concept design stages to find the optimum design parameters and operating conditions. CFD modeling was performed to analyze the effects of resonant frequency on the engine’s gas exchange behavior. To take combustion effects into account, a semi-empirical method was employed to obtain the initial and boundary conditions during the gas exchange from experiments and imported into CFD simulation. The numerical results of the gas exchange were validated at the engine speed of 5400 RPM with the experimental results. The semi-empirical method eliminated the complicated combustion simulation and significantly reduced the computational time and well-matched with experiments within 1 % error. Results showed enhanced trapping efficiency of 7.1% per 1000 RPM, and reduced scavenging efficiencies of 5.5% per 1000 RPM as speed engine’s speed increased. Comparison of the trapping and scavenging efficiencies showed an improved fuel/power efficiency equal to about 1.45 % per each 15 Hz increase in the LEA resonant frequency.
Zamani Meymian, Nima, Darzi, Mahdi, Johnson, Derek, Famouri, Parviz
Initial Investigations into the Benefits and Challenges of Eliminating Port Overlap in Wankel Rotary Engines2020-01-02804/14/2020
The Wankel rotary engine historically found limited success in automotive applications due in part to poor combustion efficiency and challenges around emissions. This is despite its significant advantages in terms of power density, compactness, vibrationless operation, and reduced parts count in relation to the 4-stroke reciprocating engine, which is now-dominant in the automotive market. A large part of the reason for the poor fuel economy and high hydrocarbon emissions of the Wankel engine is that there is a very significant amount of overlap when the ports are opened and/or closed by the rotor apices (so-called peripheral ports). This paper investigates the benefits of zero overlap from a production engine with this characteristic and the effect of configuring a peripherally-ported Wankel engine in such a manner. As discussed in the paper, arranging this condition for peripherally-ported engines unfortunately reduces the trapped compression and/or expansion ratios significantly, such that when naturally-aspirated operation is simulated, a large reduction in performance ensues. In order to demonstrate the potential of zero port overlap in Wankel engines with respect to emissions, a 2007 model year Mazda RX-8 was rebuilt, run-in, degreened, and tested on a chassis dynamometer. As standard, the engine in this vehicle is configured with no port overlap through the adoption of side intake and exhaust ports. This testing was performed in order to see subjectively how successful such an approach could be in controlling emissions. The vehicle easily met Euro 5 limits for all criteria emissions and was even better in terms of hydrocarbon emissions versus Euro 6 on the WLTP cycle, giving the lie to the belief that a Wankel engine can no longer meet current automotive emissions targets. The analytical work reported here studies the result of eliminating overlap on the performance of a peripherally-ported single-rotor Wankel engine using a 1-D model. This was implemented and correlated to the in-production Advanced Innovative Engineering (UK) Ltd 225CS engine used in the UK government-funded ADAPT project. The initial port study focused on advancing and retarding the exhaust and intake port respectively to achieve zero port overlap and then sweeping their zero-overlap positions together around the trochoid housing. The best location for the ports was then identified; this was essentially an “Otto” timing set, with broadly equal compression and expansion ratios. Notwithstanding this, potential performance was found to be severely curtailed, as was to be expected given the marked reduction in trapped compression and/or expansion ratios necessary due to peripheral porting. Countermeasures to this reduction are discussed. Those that will be studied later in the project will be reported in a later publication.
Turner, James, Turner, Matthew, Vorraro, Giovanni, Thomas, Toby
The Effects of Thick Thermal Barrier Coatings on Low-Temperature Combustion2020-01-02754/14/2020
An experimental study was conducted on a Ricardo Hydra single-cylinder light-duty diesel research engine. Start of Injection (SOI) timing sweeps from -350 deg aTDC to -210 deg aTDC were performed on a total number of five pistons including two baseline metal pistons and three coated pistons to investigate the effects of thick thermal barrier coatings (TBCs) on the efficiency and emissions of low-temperature combustion (LTC). A fuel with a high latent heat of vaporization, wet ethanol, was chosen to eliminate the undesired effects of thick TBCs on volumetric efficiency. Additionally, the higher surface temperatures of the TBCs can be used to help vaporize the high heat of vaporization fuel and avoid excessive wall wetting. A specialized injector with a 60° included angle was used to target the fuel spray at the surface of the coated piston. Throughout the experiments, the equivalence ratio, ϕ, was maintained constant at 0.4; the combustion phasing was consistently matched at 6.8 ± 0.4 deg aTDC. It can be concluded that the thick TBC cases achieved 1 to 2 percentage points improvement in combustion efficiency, and generally, a ~2 percentage points increase in indicated engine efficiency. It is also noticed that applying a dense top sealing layer to the TBC further improves the UHC emissions compared to the TBC coated piston with an unsealed surface. From the heat release analysis, it can be concluded that the TBCs have no significant impact on the heat release process and knock intensity while matching the combustion phasing; however, it reduces the intake temperature requirement by up to 20 K. The exhaust gas temperatures were expected to increase for the TBC cases, but the expected increase in exhaust temperature was not conclusive from the results observed in this study.
Yan, Ziming, Gainey, Brian, Gohn, James, Hariharan, Deivanayagam, Saputo, John, Schmidt, Carl, Caliari, Felipe, Sampath, Sanjay, Lawler, Benjamin
Optimization of Lambda across the Engine Map for the Purpose of Maximizing Thermal Efficiency of a Jet Ignition Engine2020-01-02784/14/2020
Progressively more stringent efficiency and emissions regulations for internal combustion engines have led to growing interest in advanced combustion concepts for spark ignition engines. MAHLE Jet Ignition® (MJI) is one such concept which enables ultra-lean (λ > ~1.6) combustion via air dilution. This pre-chamber-based combustion system has demonstrated highly efficient lean operation, producing efficiencies competitive with those of advanced compression ignition concepts. Compared to a traditional spark ignition engine, the additional degrees of freedom associated with Jet Ignition introduce further complexity when optimizing the system for peak efficiency throughout the engine map. The relationship between operating condition and the lambda at which peak efficiency occurs for a Jet Ignition engine has been presented in prior work by the authors. This paper further explores this complex relationship, introducing new interdependencies which must be considered in order to improve brake thermal efficiency (BTE). Experimental data is obtained from a 1.5L 3-cylinder gasoline-fueled Jet Ignition engine. An engine map of BTE is presented. An analysis at several key points throughout the engine map shows how certain parameters are adjusted to optimize BTE, providing a peak value >42%. Insight into the factors affecting efficiency is provided through parameter sweeps of pre-chamber fuel and analysis of high-speed pressure measured in both the pre-chamber and the main combustion chamber. The impact of precise fuel metering on BTE and combustion stability is highlighted. Finally, an analysis of trends in burn duration segments, pre-chamber combustion metrics, and cycle-by-cycle variation in these parameters qualifies the challenges associated with accurate prediction of lean stability limits in a jet ignition engine operating in the ultra-lean region, as well as the opportunities for further efficiency improvement through manipulation of in-pre-chamber conditions.
Peters, Nathan, Krishna Pothuraju Subramanyam, Sai, Bunce, Michael, Blaxill, Hugh, Cooper, Adrian
Prediction of Fuel Maps in Variable Valve Timing Spark Ignited Gasoline Engines Using Kriging Metamodels2020-01-07444/14/2020
Creating a fuel map for simulation of an engine with Variable Valve Actuation (VVA) can be computationally demanding. Design of Experiments (DOE) and metamodeling is one way to address this issue. In this paper, we introduce a sequential process to generate an engine fuel map using Kriging metamodels which account for different engine characteristics such as load and fuel consumption at different operating conditions. The generated map predicts engine output parameters such as fuel rate and load. We first create metamodels to accurately predict the Brake Mean Effective Pressure (BMEP), fuel rate, Residual Gas Fraction (RGF) and CA50 (Crank Angle for 50% Heat Release after top dead center). The last two quantities are used to ensure acceptable combustion. The metamodels are created sequentially to ensure acceptable accuracy is achieved with a small number of simulations. Two optimization problems are then solved using the developed metamodels, for full load and part load conditions, respectively. We demonstrate that the estimated fuel map is of high accuracy compared to the actual map. The map is obtained with about one tenth of the number of engine simulations for a full factorial design, leading to much faster predictions.
Tafreshi, Ali, Mourelatos, Zissimos
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