Browse Topic: Variable valve timing

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Development of Flex fuel Vehicle for Indian Market2026-26-01171/16/2026
This paper presents the methodology and outcomes of modifying a 1.2L naturally aspirated (NA) engine to enable flex-fuel compatibility, targeting optimal performance with ethanol blends ranging from E20 to E93. The road map for Ethanol Blending released by Govt of India call for progressively increase in ethanol blending in gasoline, with a target of 20% by April 2025. Ethanol is promoted as a renewable fuel due to its potential to reduce greenhouse gas emissions and provides an additional source of income for farmers. This work is in alignment with the broader push for development of flex-fuel vehicles, which necessitates engine adaptations capable of operating on varying ethanol blends. The primary objective was to retain the performance with E20 while mitigating the fuel consumption penalties when the vehicle is operating on higher ethanol concentrations upto E93. The engine upgrade incorporated key modifications, including optimizing the compression ratio, implementing Variable
Tyagarajan, Sethuramalingam, Pise, Chetan, Kavekar, Pratap, Agarwal, Nishant Kumar
Experimental approach to investigate VVT malfunction in SI gasoline engine.2026-26-05581/16/2026
Variable Valve Timing (VVT) is an advanced technology implemented in internal combustion engines to optimize the opening and closing timing of the intake and exhaust valves. Its primary objective is to improve engine performance, fuel efficiency, and reduce emissions by dynamically adjusting the valve timing based on the engine's operating conditions i.e. engine speed and load conditions. However, the VVT system may experience various operational issues caused due to low engine oil levels, contaminated engine oil, solenoid malfunctions, and camshaft phaser issues, which can adversely affect engine performance, fuel efficiency, and emissions. This paper provides an in-depth analysis of VVT malfunctions, specifically attributed to the resonance effect of VVT components at various engine RPMs & oil temperature. The study also explains the phenomenon causing VVT sluggishness during advance phase due to resonance between oil pulsation & VVT components. Other factors contributing to VVT
Jha, Ankur, Sau, Sanjoy, Kumar, Bharat, Sandeep, Sandeep
Engine oil fluctuation study in HLA gallery and impact of VVT cam phasing on oil fluctuation.2026-26-05591/16/2026
Oil pressure, the most fundamental to engine's performance and longevity, is critical as it ensures that the engine components are properly lubricated, cooled, and protected against wear and contamination, ultimately contributing to reliable engine performance. Due to several factors of engine, such as speed and load, there are fluctuations in oil pressure, which can be controllable and sometimes unpredictable. Controlled oil pressure fluctuations are essential for engine efficiency and adaptability, such as adaptive lubrication, temperature compensation, and hydraulic component functioning like variable valve timing, VVT, and hydraulic lash adjuster, HLA. But excessive or irregular fluctuations can indicate serious issues like excessive or sudden drops, unstable engine performance, valve train noise, improper lifter operation, VVT malfunctions, overheating, and increased wear. In this paper, HLA gallery pressure fluctuations are studied, and its impact was assessed on valve train
Kumar, Ashok, Choubisa, Manas, Kumar, Ravi, pathak, Mehul
Leveraging Advanced AI/ML Algorithms to Derive Actionable Insights from Fleet Vehicle In-Use Performance Ratio Monitoring (IUPRm) Data2026-26-06371/16/2026
In recent years, growing concerns over environmental pollution have led to the implementation of increasingly stringent emission regulations worldwide. These regulations require not only the reduction of pollutant emissions but also robust monitoring of critical emission control components under real-world driving conditions. The In-Use Performance Ratio Monitoring (IUPRm) framework quantifies how frequently onboard diagnostic systems evaluate these components within defined operational boundaries for each vehicle. IUPRm is organized into several monitoring groups, including catalyst monitoring, oxygen sensor monitoring, exhaust gas recirculation (EGR) monitoring, and gasoline particulate filter monitoring. The specific groups and monitoring requirements vary based on fuel type (gasoline or diesel), engine technologies (such as variable valve timing or EGR), and exhaust system configurations (single or dual bank). For automakers, analyzing these parameters across large vehicle fleets
Ghadge, Ganesh Narayan, Jadhav, Marisha, Hosur, Viswanatha
Technologies and Strategies for High Break Thermal Efficiency Gasoline Engine to Meet the Future CO2 Emission Targets in India2026-26-00721/16/2026
The Indian automobile industry is experiencing a significant shift, propelled by environmental necessities and national climate obligations set at the CoP26 summit, aiming for a 45% decrease in CO₂ emissions by 2030 and reaching carbon neutrality by 2070 [1]. Transportation continues to be a significant source of air pollution; consequently, India is enhancing its regulatory frameworks with BS VI Stage 2 regulations, CAFE Phase III norms set for 2027, and CAFE Phase IV by 2032 [2]. Furthermore, the transition from MIDC to WLTP driving cycle is meant to increase the accuracy of the efficiency and emissions assessments [2]. To comply to these upcoming regulations, the automotive industry is moving toward producing high efficiency engines in India. A naturally aspirated (NA) 1.5L, 4- cylinder inline gasoline engine was selected from Indian market for this study. Maximum Brake Thermal Efficiency (BTE) of this engine is around 35%. Assessment of new technologies were performed by
Emran, Ashraf, Jagodzinski, Bartosch, Garg, Shivam, Fischer, Marcus, Franzke, Bjoern
Experimental Study on Quality Control and Variable Valve Timing Strategy of Hydrogen Engine for High Efficiency and Low Emission at Low Load2024-01-509510/15/2024
In order to reduce the pumping loss of low loads and maximize the lean combustion advantage of hydrogen, the paper proposes a load control strategy based on hydrogen mass, called quality control, for improving thermal efficiency and emissions at low loads. The advantages of quality control and the effect of VVT on the combustion performance of hydrogen internal combustion engines under low loads were discussed. The results show that when the relative air–fuel ratio (λ) increases to more than 2.5, the NOx emissions are reduced to less than 3.5 g/kW · h at the brake mean effective pressure (BMEP) below 8 bar, especially when the BMEP is less than 5 bar, the NOx is within 0.2 g/kW · h. Compared to quantity control based on air mass, the quality control strategy based on hydrogen mass achieves over a 2.0% reduction in pumping loss at BMEP levels lower than 4.4 bar. Furthermore, it enhances thermal efficiency by up to 5% at low loads, while maintaining NOx emissions within 0.2 g/kW · h at
Li, Yong, Chen, Hong, Fu, Zhen, Du, Jiakun, Wu, Weilong
Effect of Lash Sensitivity on Engine Brake Performance and Valvetrain Dynamics2024-26-02711/16/2024
Engine brakes are much effective to retard the heavy-duty vehicle during deceleration compared to the traditional clutch-brake system. Therefore, the current upgrading vehicle industry and the evolving road infrastructure for better connectivity along with regulations, demands the acclimatizing engine brake (EB) system. To achieve this, it is equally important to have high speed variable valve actuation dynamic valvetrain system. To help develop this system, Model Based Product Development approach is used primarily at Eaton. In the present work, the effect of valve lash sensitivity on valvetrain (VT) dynamics and engine brake performance is studied. This helps to understand the coupled effect of multi-physics on valve lift opening, on valve lift loss and on VT system compliance. In addition to this engine brake power becomes very sensitive under such situations. To study this a medium duty 6-cylinder engine model is developed from the GT-POWER engine Fast Response Model (FRM) database
Jadhav, Priyanka D., Joshi, Vasu, Milind, T. R., Bagal, Nilesh
A study of engine oil aeration in IC engines and factors contributing it.2024-26-03701/16/2024
The lubrication system of an internal combustion engine is a crucial component that performs a variety of functions, including lowering friction, cooling, supporting load and cleaning debris from the engine's various moving components. Oil aeration refers to the trapping of air bubbles in lubricating oil. High oil aeration can have a detrimental effect on engine performance since modern engines are equipped with parts such as VVT, HLA, RFF, PCJ, LCJ, and other components; whose operation is substantially impacted by the amount of air in circulating oil. In this study, an Inline 4-cylinder NA DOHC gasoline engine was tested with a densimeter type aeration measuring machine. Test equipment layout which consists of hose diameter, hose length etc. were designed, fabricated, and instrumented to operate under different test conditions. Visual observations and quantitative measurements of oil aeration was performed in the oil sump. The purpose of this study is to evaluate the impact of
Attri, Mayank, Yadav, Vimal, kamboj, Jagdish
testSAE-PP-0878910/9/2023
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SintzADMIn, Jeneane
Experimental Investigation of a Methanol Fueled SI engine at full load using a Central Composite Design. 2022-01-06193/29/2022
The large difference in fuel properties between methanol and gasoline demand the development of a dedicated spark ignition (SI) engine in order to exploit methanol’s properties for maximum thermal efficiency, rather than using the flex-fuel engines of today. In order to develop such an engine, proven technologies on a high efficiency gasoline engine are a good reference point to start with. The engine setup used in this work was a 1.6L turbocharged Volvo T3 engine equipped with variable valve timing (VVT) and a low pressure EGR loop. A central composite design (CCD) was used to quantify the influence of five control parameters on the brake thermal efficiency (BTE) and main energy losses when running the engine on methanol at full load and a fixed engine speed of 1700 rpm. The set of control parameters consist of the intake valve opening timing, exhaust valve opening timing, opening of the waste gate, opening of the EGR valve and closing of the backpressure valve. The main energy losses
Suijs, Ward, Verhelst, Sebastian
Low Temperature Combustion Exploration with Negative Valve Overlap2022-01-05493/29/2022
Progressively stringent emission regulations and increasing regulatory demand on fuel economy have been leading to advanced combustion development. The low temperature combustion (LTC), as known as homogenous charge compression ignition, is a promising technology in reducing exhaust emissions and improving efficiency. However, its operation range is limited to low load due to the reduced volumetric efficiency and the high pressure rise rate. Additionally, how to effectively control the combustion phasing is another challenge in realizing the associated combustion gain. In this work, an advanced valve control mechanism known as continuously variable valve duration (CVVD) and continuously variable valve timing (CVVT) was used for both intake and exhaust valvetrains to enable negative valve overlap (NVO) to trap hot residuals and promote multipoint simultaneous ignition. Heat release phasing was controlled by varying fueling scheme and by adjusting the amount of NVO. Parametric study on
Zhu, Shengrong, JOO, NAHM ROH, Hollowell, Jeffrey, Ha, Kay, Shirley, MARK, Fantin, NICK, WAGH, MAYURI
Control oriented engine model development for Model-based PPC control2022-01-05753/29/2022
In this work, a model-based control approach for Partially Premixed Combustion (PPC) engines is introduced. PPC is a next-generation combustion technology, which has the potential to achieve both ultra-low emissions and high efficiency. As the PPC concept is characterized by a complex chemical-physical process of low-temperature kinetic reactions, it lacks direct trigger of ignition and combustion as well as it is sensitive to varying operating conditions. These complex nature of PPC makes it challenging to control the combustion for optimum efficiency and emissions at broad engine operation with low cyclic variability and without exceeding the maximum allowed in-cylinder pressure rise rate or peak pressure. The nonlinear relationship between the control input and combustion system response makes that conventional lookup table-based control might need too many maps and calibration effort, thus no longer feasible for real operation scenarios. A model-based control approach is proposed
Pan, Wang, Bekdemir, Cemil, Willems, Frank
Development of a Control-Oriented Cylinder Air-Charge Model for Gasoline Engines with Dual Independent Cam Phasing2022-01-04843/29/2022
Cylinder air-charge is one of the most important parts of the torque control in a gasoline engine, due to the necessity to keep a stoichiometric air-fuel ratio for the three-way catalyst to work efficiently. Throttle and phasing of the camshafts are actuators that have a big effect on the cylinder air-charge, this results in a cross-coupling between the actuators. One approach to handle the cross-coupling that occurs with multiple actuators is to use model predictive control (MPC), that handles the cross-coupling through the use of models and optimization. Models that support computation of gradients and hessians are desirable for use in MPC, which is not supported by a look-up table approach. Through the use of cylinder pressure measurements, from a 4 cylinder engine with dual independent cam phasing, and simulation, the effects from variable valve timing on the cylinder air-charge are investigated during the valve overlap period. A phase described using the path of least resistance
Holmbom, Robin, Eriksson, Lars
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
Analysis of Cylinder to Cylinder Variations in a Turbocharged Spark Ignition Engine at lean burn operations2022-32-00441/9/2022
In recent years, the improvement in the fuel efficiency and reduction in CO2 emission from internal combustion engines has been an urgent issue. The lean burn technology is one of the key technologies to improve thermal efficiency of SI engines. However, combustion stability deteriorates at lean burn operations. The reduction in cycle-to-cycle and cylinder-to-cylinder variations is one of the major issues to adapt the lean burn technique for production engines. However, the details of the causes and mechanisms for the combustion variations under the lean burn operations have not been cleared yet. The purpose of this study is to control cylinder to cylinder combustion variation. A conventional turbocharged direct injection SI engine was used as the test engine to investigate the effect of engine control parameters on the cylinder to cylinder variations. The engine speed is set at 2200 rpm and the intake pressure is set at 58, 78, 98 kPa respectively. In-cylinder pressure, intake
Yamaizumi, Ryo, Shi, Haoyun, Kuboyama, Tatsuya, Moriyoshi, Yasuo
Describing the Auto-Ignition Quality in Small, Air Cooled, Two Stroke Engines2022-32-00631/9/2022
Auto-ignition quality is one of the most important properties in gasoline. Auto-ignition quality is today described by the Motor Octane Number (MON) and the Research Octane Number (RON). For modern, light duty, gasoline engines it has been quite well established that RON is the most accurate number. However, no study has been performed on hand held forest and garden products, such as chainsaws. Is the auto-ignition quality best described in the same way for these engines as for light duty engines? In this paper, a matrix of six different fuels with different combinations of MON and RON values were tested on a Husqvarna 550 XP Mark II, a modern air cooled, sequential stratified scavenging 2-stroke chainsaw engine. Ignition timing sweeps were performed and knock limited spark advance (KLSA) were calculated. Then the data has been analyzed with a multi-variate analysis of KLSA against both MON and RON to try to determine how MON and RON should be combined to best describe the anti-knock
Risberg, Per, Elm, Thomas, Bergman, Mikael, Hellquist, Fredrik, Karvo, Anna, Tripathi, Rupali
Generating some more TasksSAE-PP-0049311/10/2021
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Kelly, Jason
Numerical Simulation to Assess Implementation of Variable Valve Timing and Lift Technique on a BS-VI LMD Diesel Engine for Fuel Efficiency Improvement2021-26-04219/22/2021
In order to stand apart from the competition, there is an ever growing demand in Indian commercial vehicle segments to reach higher fuel economy while achieving the emission goals set by the BS-VI norms. With emissions standard set by BS-VI, novel techniques to improve fuel efficiency have to be considered that have least impact with respect to NOx and soot emissions. The optimization of exhaust and intake valve lifts with respect to engine speed, technology commonly known as variable valve lift and timing (VVT/VVL), has been implemented in many passenger vehicles propelled by gasoline engine. The aim of this work is do initial assessment of utilizing the VVL method on a LMD commercial vehicle diesel engine. A 3.8 litre BS-VI turbocharged EGR engine is used for this study. Valve lift and timing optimization for better fuel efficiency at rated power engine speed is carried out by using one-dimensional thermodynamic simulation software AVL BOOST. For this purpose complete engine from
Kaundabalaraman, Kaarthic, Bisht, Jasvir Singh, Rathi, Hemantkumar Mohanlal
The New 2.0L Turbocharged GDI Engine from SAIC Motor2021-01-12309/21/2021
SAIC Motor Corporation Limited (SAIC Motor) has developed an all new 2.0 L 4-cylinder turbocharged gasoline direct injection engine to meet the market demand and increasingly stringent requirement of CAFE and tail-pipe emission regulations. A series of advanced technologies have been employed in this engine to achieve high efficiency, high torque and power output，fast response low-end torque performance, refined NVH performance, all at market leading level, and low engine-out emissions. These main technologies include: side mount gasoline direct injection with 35MPa fuel injection system, integrated exhaust manifold, high tumble combustion system, 2-step intake variable valve lift (DVVL) with Miller Cycle, efficient turbo charging with electric wastegate (EWG), light weight and compact structural designs, NVH measures including balancer system with silence gear, friction reduction measures, optimized thermal management, etc. As a result of application of these technologies and
Xu, Zheng, Zhu, Guohua, Zhou, Zhou, wang, Shuqing, Yang, Yang, Wang, Yanjun, Cheng, Chuanhui, Li, WeiJun, Zhang, Xiaomao, wang, Xiaobo
Development of a PN Surrogate Model Based on Mixture Quality in a GDI Engine2021-24-00139/5/2021
A novel surrogate model is presented, which predicts the engine-out Particle Number (PN) emissions of a light-duty, spray-guided, turbo-charged, GDI engine. The model is developed through extensive CFD analysis, carried out using the Siemens Simcenter STAR-CD, and considers a range of part-load operating conditions and single-variable sweeps where control parameters such as start of injection and injection pressure are varied in isolation. The work is attached to the Ford-led APC6 DYNAMO project, which aims to improve efficiency and reduce harmful emissions from the next generation of gasoline engines. The CFD work focused on the air exchange, fuel spray and mixture preparation stages of the engine cycle. A combined Rosin-Rammler and Reitz-Diwakar model, calibrated over a wide range of injection pressure, is used to model fuel atomization and secondary droplets break-up. A validated approach, based on the Bai-Onera model of droplet-wall interaction, is used to capture the details of
Sciortino, Davide Domenico, Cary, Mark, Verma, Sunny, Biagiotti, Federico, Hopkins, Edward, Jiang, Changzhao, Witt, Dennis, Bonatesta, Fabrizio
Mitigating Vibration for a Heavy-Duty Diesel Cylinder Deactivation Truck2021-01-06614/6/2021
Commercial vehicles require fast aftertreatment heat up in order to move the selective catalyst reduction (SCR) into the most efficient temperature range to meet upcoming NOx regulations. Heavy duty cylinder deactivation (CDA) is an important technology to meet these regulations. One of the challenges with implementing CDA in the heavy-duty market is to ensure acceptable engine and vehicle vibration. The purpose of this paper is to mitigate CDA vibration on a vehicle to acceptable levels. Emphasis was placed at the idle operating condition. Idle is the most challenging operating mode to enable, as deactivating cylinders reduces the frequency of the forcing function due to engine firing, which leads to a need to isolate these lower frequencies. A focused modal analysis of the engine (source), frame (path), and cabin (path/receiver) was used to characterize the vehicle system. The work showed that a change in cab mounts reduced the observed vibration levels dramatically while operating
Pieczko, Matthew, McCarthy, Jr., James, Hamler, Jesse
Numerical Parametric Study of a Six-Stroke Gasoline Compression Ignition (6S-GCI) Engine Combustion - Part III2021-01-04014/6/2021
The aim of this paper is to computationally investigate the combustion behavior and energy recovery processes of a six-stroke gasoline compression ignition (6S-GCI) engine that employs a continuously variable valve duration (CVVD) technique, under highly diluted, low-temperature combustion (LTC) conditions. The effects of variation of parameters concerning injection spray targeting (number of fuel injector holes. injector nozzle size and spray included angle) and combustion chamber geometry (piston bowl design) are analyzed using an in-house 3D CFD code coupled with high-fidelity physical sub-models with the Chemkin library in conjunction with a skeletal chemical kinetics mechanism for a 14-component gasoline surrogate fuel. The foundation of this study stems from the authors previous works, regarding the effects of the change in various operating parameters on the overall performance of 6S-GCI engine, which show that both kinetically-controlled mode of combustion (KCM) and mixing
Rajput, Oudumbar, Ra, Youngchul, Purushothaman, Ashwin Karthik, Ha, Kyoung-Pyo
7.0.112 - Design and Development of Variable Valve Actuation (VVA) Mechanism Concept for Multi-Cylinder EngineSAE-PP-002882/4/2021
The desire for higher fuel economy, improved performance and driveability expectations of customers from engines are gradually increasing along with stringent emission regulations set by the government. Many original engine manufacturing companies are prompted to consider the application of higher function variable valve actuation mechanisms in their next generation vehicles as a solution. The VVA is a generalized term used to describe any mechanism or method that can alter the shape or timing of a valve lift event within an internal combustion engine. The VVA allows lift, duration or timing (in various combinations) of the intake and/or exhaust valves to be changed while the engine is in operation. Engine designers are prompted to consider Variable Valve Actuation (VVA) system because of the inherent compromises with fixed valve events. The major goal of a VVA engine is to control the amount of air inducted into the engine which is a direct measure of torque. This work presents a
Volkswagen readies new-generation Golf R20AUTP11_1211/1/2020
Although the memorable 6-cylinder character of the original R32 has given way to turbocharged 4-cylinder propulsion in recent years, Volkswagen continues to deliver V6-type power for the performance flagship of the Golf lineup, injecting the all-new 2022 Golf R with 315 hp claimed from a fourth-generation version of the company's EA888 2.0-L. The company said Golf R's engine now is the most powerful iteration of the turbocharged and direct-injected EA888 yet released for production. The R variant of the recently launched eighth-generation Golf compact car also is fitted with a more-sophisticated 4Motion all-wheel-drive (AWD) system. And in a wink to the R's renown as the ultimate VW performance car, the 2022 Golf R - not coming to the U.S. market until late next year - also will continue to offer the choice of a manual transmission at a time when the few remaining shift-it-yourself models from every automaker continue to disappear.
Visnic, Bill
Assessing the Efficiency of a New Gasoline Compression Ignition (GCI) Concept2020-01-20689/15/2020
A practical Gasoline Compression Ignition (GCI) concept is presented that works on standard European 95 RON E10 gasoline over the whole speed/load range. A spark is employed to assist the gasoline autoignition at low loads; this avoids the requirement of a complex cam profile to control the local mixture temperature for reliable autoignition. The combustion phasing is controlled by the injection pattern and timing, and a sufficient degree of stratification is needed to control the maximum rate of pressure rise and prevent knock. With active control of the swirl level, the combustion system is found to be relatively robust against variability in charge motion, and subtle differences in fuel reactivity. Results show that the new concept can achieve very low fuel consumption over a significant portion of the speed/load map, equivalent to diesel efficiency. The efficiency is worse than an equivalent diesel engine only at low load where the combustion assistance operates. In this work, a
Cracknell, Roger, Bastaert, Dimitri, Houille, Sebastien, Châtelain, Julien, Larguier, Olivier, Beaugé, Yvon, Gente, Florian, Nicolas, Baptiste, Prevet, Sylvain, Fandakov, Alexander, Rieß, Michael, Costenoble, Ortwin, de Groot, Timo, Duffour, Florence, Pellegrini, Leonardo, Rogerson, John, Hamje, Heather
Numerical Methods on VVA and VCR Concepts for Fuel Economy Improvement of a Commercial CNG Truck2020-01-20839/15/2020
Natural gas has been used in spark-ignition (SI) engines of natural gas vehicles (NGVs) due to its resource availability and stable price compared to gasoline. It has the potential to reduce carbon monoxide emissions from the SI engines due to its high hydrogen-to-carbon ratio. However, short running distance is an issue of the NGVs. In this work, methodologies to improve the fuel economy of a heavy-duty commercial truck under the Japanese Heavy-Duty Driving Cycle (JE05) is proposed by numerical 1D-CFD modeling. The main objective is a comparative analysis to find an optimal fuel economy under three variable mechanisms, variable valve timing (VVT), variable valve actuation (VVA), and variable compression ratio (VCR). Experimental data are taken from a six-cylinder turbocharged SI engine fueled by city gas 13A. The 9.83 L production engine is a CR11 type with a multi-point injection system operated under a stoichiometric mixture. For minimizing optimal valve strategy selections and
Sok, Ratnak, Takeuchi, Kazuki, Yamaguchi, Kyohei, Kusaka, Jin
Simulation Study of Force Distribution in the Multiple Linkage System of a Spark Ignition Engine Operating in the Atkinson Cycle2020-01-22269/15/2020
The tests were carried out on an 3D engine model with an unconventional multiple linkage system. Compared to a classic crankset, the mechanism consists of more elements. In this multiple linkage system the camshaft, the piston rod and the main rod are connected to one common element. The camshaft rotating during operation at twice the speed of the crankshaft makes possible to achieve different piston stroke lengths with each revolution. With proper synchronization of the camshaft revolution with the crankshaft, the suction and compression stroke is smaller in relation to the expansion and exhaust strokes. For this reason, the Atkinson cycle was obtained without interfering with the variable valve timing. The thermal cycle is characterized by increased theoretical thermal efficiency. Due to the unique mechanism, the piston movement has different characteristics compared to classic solutions. Therefore, work was undertaken to analyze the distribution of forces in the system. For the
Urbański, Patryk, Daszkiewicz, Pawel, Bajerlein, Maciej, Rymaniak, Lukasz, Merkisz, Jerzy
Electrohydraulically Actuated Valve TrainTBMG-371997/1/2020
Internal combustion engines require valves to aspirate and discharge gases. Engine designers require a high degree of flexibility to improve efficiency, reduce pollutants, and optimize the use of renewable fuels. Currently, the gas exchange valves of four-stroke engines are controlled through camshaft drives. Despite some complex additional mechanics, the flexibility of such camshaft-driven systems remains limited. An electrohydraulically actuated valve train — the FlexWork valve train - was developed that enables completely free adjustment of stroke and timing, while at the same time being robust and cost-effective.
Commercial trucks employ range of power systems20TOFHP06_106/1/2020
Regulations continue to transform the powerplants used in commercial trucks, making fuel consumption and emissions reductions twin goals for many OEMs, upfitters and aftermarket suppliers at the NTEA Work Truck Show. Green trends and mileage requirements drove trends at the 20th annual show, which also addressed electrification and alternative fuels at the show's Green Trucks Summit. “Some of the major challenges our industry will face in the coming decade are the result of emissions regulations,” said Shaun C. Skinner, president, Isuzu Commercial Truck of America. The Green Trucks Summit focused largely on electrification plans, but a couple major product announcements at the show were petroleum-based. Isuzu announced a pair of gasoline engines, while Mack unveiled its Class 6 and 7 medium-duty trucks, which use 6.7-L diesel engines.
Costlow, Terry
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
Turner, James, Turner, Matthew, Vorraro, Giovanni, Thomas, Toby
Downsized-Boosted Gasoline Engine with Exhaust Compound and Dilute Advanced Combustion2020-01-07954/14/2020
This article presents experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5: 1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expanded. The main goal of this work is to implement in this engine, advanced lean/dilute low-temperature combustion for low-NOx and high efficiency operation, and to address the transition between the different operating modes. Those include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion at
Dernotte, Jeremie, Najt, Paul M., Durrett, Russell P.
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
Tafreshi, Ali, Mourelatos, Zissimos
The Use of Piezoelectric Washers for Feedback Combustion Control2020-01-11464/14/2020
The use of piezoelectric cylinder pressure sensors is very popular during engine testing, but cylinder pressure information is becoming mandatory also in several on-board applications, where Low Temperature Combustion (LTC) approaches require a feedback control of combustion, due to poor combustion stability and the risk of knock or misfire. Several manufacturers showed the capability to develop solutions for cylinder pressure sensing in on-board automotive and aeronautical applications, and some of them have been patented. The most straight-forward approach seems the application of a piezo-electric washer as a replacement of the original part equipping the spark plug; the injector could also be used to transfer the cylinder pressure information to the piezoelectric quartz, in diesel or Gasoline Direct Injections (GDI) engines. The paper describes the features of signals acquired using piezoelectric washers, discussing possible applications, highlighting the factors which impact the
Corti, Enrico, Abbondanza, Marco, Ponti, Fabrizio, Raggini, Lorenzo
Combustion System Optimization of a Light-Duty GCI Engine Using CFD and Machine Learning2020-01-13134/14/2020
In this study, the combustion system of a light-duty compression ignition engine running on a market gasoline fuel with Research Octane Number (RON) of 91 was optimized using computational fluid dynamics (CFD) and Machine Learning (ML). This work was focused on optimizing the piston bowl geometry at two compression ratios (CR) (17 and 18:1) and this exercise was carried out at full-load conditions (20 bar indicated mean effective pressure, IMEP). First, a limited manual piston design optimization was performed for CR 17:1, where a couple of pistons were designed and tested. Thereafter, a CFD design of experiments (DoE) optimization was performed where CAESES, a commercial software tool, was used to automatically perturb key bowl design parameters and CONVERGE software was utilized to perform the CFD simulations. At each compression ratio, 128 piston bowl designs were evaluated. Subsequently, a Machine Learning-Grid Gradient Algorithm (ML-GGA) approach was developed to further optimize
Badra, Jihad, khaled, Fethi, Sim, Jaeheon, Pei, Yuanjiang, Viollet, Yoann, Pal, Pinaki, Futterer, Carsten, Brenner, Mattia, Som, Sibendu, Farooq, Aamir, Chang, Junseok
The Effect of Heavy-Duty Diesel Cylinder Deactivation on Exhaust Temperature, Fuel Consumption, and Turbocharger Performance up to 3 bar BMEP2020-01-14074/14/2020
Diesel Cylinder Deactivation (CDA) has been shown in previous work to increase exhaust temperatures, improve fuel efficiency, and reduce engine-out NOx for engine loads up to 3 bar BMEP. The purpose of this study is to determine whether or not the turbocharger needs to be altered when implementing CDA on a diesel engine. This study investigates the effect of CDA on exhaust temperature, fuel efficiency, and turbocharger performance in a 15L heavy-duty diesel engine under low-load (0-3 bar BMEP) steady-state operating conditions. Two calibration strategies were evaluated. First, a “stay-hot” thermal management strategy in which CDA was used to increase exhaust temperature and reduce fuel consumption. Next, a “get-hot” strategy where CDA and elevated idle speed was used to increase exhaust temperature and exhaust enthalpy for rapid aftertreatment warm-up. The “stay-hot” CDA strategy demonstrated increased exhaust temperatures up to 200°C while simultaneously reducing fuel consumption by 5
Morris, Andrew, McCarthy, James
A Real-Time Capable and Modular Modeling Concept for Virtual SI Engine Development2020-01-05774/14/2020
Spark Ignited (SI) combustions engines in combination with different degrees of hybridization are expected to play a major role in future vehicle propulsion. Due to the combustion principle and the related thermodynamic efficiency, it is especially challenging to meet future CO2 targets. The layout and optimization of the overall system requires novel methods in the development process which feature a seamless transition between real and virtual prototypes. Herein, engine models need to predict the entire engine operating range in steady-state and transient conditions and must respond to all relevant control inputs. In addition, the model must feature true real-time capability. This work presents a holistic and modular modeling framework, which considers all relevant processes in the complex chain of physical effects in SI combustion. The basis is a crank-resolved cylinder model which describes gas exchange and compression to determine the thermodynamic state and turbulence conditions
Poetsch, Christoph, Wurzenberger, Johann, Katrasnik, Tomaz
Numerical Investigation of Diesel-Spray-Orientated Piston Bowls on Natural Gas and Diesel Dual Fuel Combustion Engine2020-01-03114/14/2020
Low combustion efficiency and high hydrocarbon emissions at low loads are key issues of natural gas and diesel (NG-diesel) dual fuel engines. For better engine performance, two diesel-spray-orientated (DSO) bowls were developed based on the existing diesel injector of a heavy-duty diesel engine with the purpose of placing more combustible natural gas/air mixture around the diesel spray jets. A protrusion-ring was designed at the rim of the piston bowl to enhance the in-cylinder flame propagation. Numerical simulations were conducted for a whole engine cycle at engine speed of 1200 r/min and indicated mean effective pressure (IMEP) of 0.6 MPa. Extended coherent flame model 3 zones (ECFM-3Z) combustion model with built-in soot emissions model was employed. Simulation results of the original piston bowl agreed well with the experimental data, including in-cylinder pressure and heat released rate (HRR), as well as soot and methane emissions. Turbulence kinetic energy, IMEP and methane
Shen, Zhaojie, Wang, Xinyan, Zhao, Hua, Shen, Yitao, Yang, Jianguo
Effect of a Cylinder Deactivation Actuator with Electro-Mechanical Switching System on Fuel Economy of an Automotive Engine2020-01-14084/14/2020
This paper introduces a two-step CDA mechanism equipped with an electro-mechanical switching system, which can be applied to OHC valve trains with end pivot rocker arms, and can operate two valves simultaneously with a single cam. The electro-mechanical switching system is driven by a dedicated solenoid, so the latching and unlatching processes are not affected by the temperature and pressure of the engine oil. Therefore, not only the dynamic stability can be secured at the time of mode switching but also the operation delay time can be kept short enough. To verify the effect of the CDA system on the fuel economy, a four-cylinder 2.0L gasoline engine with the intake port injection was selected and tested on an engine dynamometer. The effect of the present apparatus was evaluated by measuring the fuel economy of the engine in the two test modes: Federal Test Procedure-75 (FTP-75) and Worldwide Harmonized Light Vehicles Test Procedure (WLTP). The optimal operating conditions were
Lee, Dong Hyeong, Kim, Dojoong, Jeon, Wan Jae, Hong, Yong Seok, Park, Jong Wung
Impact of Miller Cycle Strategies on Combustion Characteristics, Emissions and Efficiency in Heavy-Duty Diesel Engines2020-01-11274/14/2020
This study experimentally investigates the impact of Miller cycle strategies on the combustion process, emissions, and thermal efficiency in heavy-duty diesel engines. The experiments were conducted at constant engine speed, load, and engine-out NOx (1160 rev/min, 1.76 MPa net IMEP, 4.5 g/kWh) on a single cylinder research engine equipped with a fully-flexible hydraulic valve train system. Early Intake Valve Closing (EIVC) and Late Intake Valve Closing (LIVC) timing strategies were compared to a conventional intake valve profile. While the decrease in effective compression ratio associated with the use of Miller valve profiles was symmetric around bottom dead center, the decrease in volumetric efficiency (VE) was not. EIVC profiles were more effective at reducing VE than LIVC profiles. Despite this difference, EIVC and LIVC profiles with comparable VE decrease resulted in similar changes in combustion and emissions characteristics. Miller cycle operation at constant intake pressure
Garcia, Erick, Triantopoulos, Vassilis, Boehman, Andre, Taylor, Maxwell, Li, Jian
Experimental and 1D Numerical Investigations on the Exhaust Emissions of a Small Spark Ignition Engine Considering the Cylinder-by-Cylinder Variability2020-01-05784/14/2020
This paper reports a numerical and experimental analysis on a twin-cylinder turbocharged Spark Ignition engine carried out to investigate the cylinder-to-cylinder variability in terms of performance, combustion evolution and exhaust emissions. The engine was tested at 3000 rpm in 20 different steady-state operating conditions, selected with the purpose of observing the influence of cylinder-by-cylinder A/F ratio variations and the EGR effects on the combustion process and exhaust emissions for low to medium/high loads. The experimental outcomes showed relevant differences in the combustion evolution (characteristic combustion angles) between cylinders and not negligible variations in the emissions of the single cylinder exhaust and the overall engine one. This misalignment resulted to be due to differences in the injected fuel amount by the port injectors in the two cylinders, mainly deriving from the specific fuel rail geometry. The experimental data were then used to validate a 1D
Marchitto, Luca, Teodosio, Luigi, Tornatore, Cinzia, Valentino, Gerardo, Bozza, Fabio
Application of the Passive MAHLE Jet Ignition System and Synergies with Miller Cycle and Exhaust Gas Recirculation2020-01-02834/14/2020
Driven by legislation, economics and increasing societal awareness, engine and vehicle manufacturers are facing increasing pressure to reduce vehicle emissions and deliver improved fuel economy. Significant reductions in carbon dioxide (CO2) emissions will need to be achieved to meet these requirements whilst at the same time satisfying the more stringent forthcoming emissions regulations. This focus on techniques to reduce the tailpipe CO2 is increasing the interest in novel combustion technologies, including dilute combustion in gasoline engines. The pre-chamber based jet ignition concept produces high energy jets of partially combusted species that induce ignition at multiple locations in the main combustion chamber to enable rapid, stable combustion, even with dilute mixtures. The present study focusses on the beneficial synergies of the pre-chamber system with high geometric compression ratio (CR), Miller cycle operation and cooled external exhaust gas recirculation (EGR). The
Cooper, Adrian, Harrington, Anthony, Bassett, Michael, Reader, Simon, Bunce, Michael
Discharge Current Management for Diluted Combustion under Forced Flow Conditions2020-01-11184/14/2020
Lean burn or EGR diluted combustion with enhanced charge motion is effective in improving the efficiency of spark ignition engines. However, the ignition process under these conditions is getting more challenging due to higher ignition energy required by the lean or diluted mixture, as well as the interactions of the gas flow on the flame kernel. Enhanced spark discharge energy is essential to initiate the combustion under these conditions. Moreover, the discharge process should be more carefully controlled to improve the effectiveness of the spark. In this study, spark ignition systems with boosted discharge energy are used to ignite diluted air-fuel mixture under forced flow conditions. The impacts of the discharge current level, the discharge duration and the discharge current profile on the ignition are investigated in detail using optical diagnosis. It is evident from the results that extended discharge duration helps promote the flame propagation, though the effectiveness is
Yang, Zhenyi, Wang, Linyan, Sandhu, Navjot S., Yu, Xiao, Zheng, Ming
Development of Fast Idle Catalyst Light-Off Strategy for Gasoline Compression Ignition Engine - Part 12020-01-03164/14/2020
The present investigation pertains to the development of fast idle catalyst light-off strategy for a light duty gasoline compression ignition (GCI) engine. The engine cold start fast idle operation poses a problem of increased criteria emissions if the catalyst is not activated during the warm up period. Therefore, a control strategy is proposed here to minimize the criteria pollutants during the fast idle phase via enabling fast catalyst light off in a GCI engine and relying on the spark ignition of a globally stoichiometric fuel air mixture. The engine has unique design features such as certain geometry configuration between spark plug and fuel injector arrangement, and the location of spark plug in a high compression ratio (CR) diesel-like combustion chamber. The experiments were performed in a single cylinder GCI engine at cold start fast idle conditions using certification gasoline fuel (RON 91). Split fuel injection and extremely retarded spark timing strategy are applied to
Raman, Vallinayagam, Viollet, Yoann, Chang, Junseok
Methodology to standardize and improve the calibration process of a 1D model of a GTDI engine2020-01-10084/14/2020
Modeling techniques are one of most useful tools during the first stages of the ICE design. They allow to analyze and predict the entire engine performance, reduce costs and resources and surely accelerate its development. For that purpose, a former and suitable calibration process is needed in order to attain reliable and robust models. Therefore, in this work a methodology is proposed to standardize and improve the calibration of a whole 1D engine model. In this case, it has been applied to a gasoline, turbocharged, direct injection engine with variable nozzle turbine and variable valve timing technologies. This calibration procedure is mainly distinguished by insulating the different engine parts, decoupling the turbocharger, using PI controls to find fitting parameters and checking and validating mean and instantaneous variables related to flow conditions inside the engine. Moreover, it requires experimental data and a previous combustion analysis of some steady operating points
Serrano, Jose, Climent, Hector, Navarro, Roberto, González-Domínguez, David
An Investigation into the Effects of Variable Valve Actuation in a Heavy-Duty Gasoline Compression Ignition Engine2020-01-11304/14/2020
The application of variable valve actuation (VVA) has been well demonstrated for improvements in fuel economy and reduced emissions in spark-ignited (SI) and diesel engine applications. The current research numerically investigates effects of VVA in a prototype heavy-duty Gasoline Compression Ignition (GCI) engine modified from a MY2013 Cummins ISX15 heavy-duty diesel engine. For the GCI engine system, the geometric compression ratio was modified to 15.7, and the RON92 gasoline was assumed as a fuel . In a sister paper, a 3-D CFD analysis was conducted to characterize effects of reduced effective compression ratios on the fuel efficiency improvements and reduced soot & NOx emissions for RON92 GCI combustion at mid-to-high engine load conditions. As a follow-up, the current research conducted a 1-D system level analysis to evaluate the effects of VVA on the boost system requirements for the RON92 GCI combustion. Reduction of effective compression ratio by means of early intake valve
Kumar, Praveen, Zhang, Yu, Traver, Michael, Watson, John
Analytical Approach to Characterize the Effect of Engine Control Parameters and Fuel Properties on ACI Operation in a GDI Engine2020-01-11414/14/2020
Advanced compression ignition (ACI) operation in gasoline direct injection (GDI) engines is a promising concept to reduce fuel consumption and emissions at part load conditions. However, combustion phasing control and the limited operating range in ACI mode are a perennial challenge. In this study the combined impact of fuel properties and engine control strategies in ACI operation are investigated. A design of experiments method was implemented using a three level orthogonal array to determine the sensitivity of engine control parameters on the engine load, combustion noise and stability under low load ACI operation for three RON 98 gasoline fuels, each exhibiting disparate chemical composition. Furthermore, the thermodynamic state of the compression histories was studied with the aid of the pressure-temperature framework. Due to the compression ratio constraints imposed by knock limited SI operation, considerable intake temperature heating was required and ACI operation resulted in
Rohwer, Johannes, Shah, Ashish, Rockstroh, Toby
Developing High-Performance Motorcycle Oils2019-32-05051/24/2020
Published motorcycle lubricant research often focuses on developments to meet certain specifications, regulatory requirements, or a combination of the two. Seemingly missing from the literature is research where the primary goal is development of a lubricant that enables maximum torque, power and acceleration from a machine for the purpose of winning races. The present study combines the two areas of research, where a high-performance motorcycle engine oil platform is developed to be used in competition, while simultaneously meeting the necessary regulations and specifications to be useful for commuters and leisure riders alike. Well-known are the demands on a motorcycle oil, which must lubricate and protect the crankcase, clutch and gears, all of which have competing requirements such that a strategy to improve the performance in one area can cause a detriment in another. Formulating for racing engines that are typically much more powerful than production versions further exacerbates
Marcella, Mike, Johnson, Aaron
Simulation Analysis of the Scavenging Process of a Uniflow and Loop Scavenging Concept2019-32-05491/24/2020
The two-stroke engine, as a today unconventional concept in automotive applications, has a great potential for a relaunch in the fast-growing market of Plugin Hybrid Electric Vehicle (PHEV) or Range Extender Electric Vehicle (REX) [2, 3, 4, 8, 9]. An efficient scavenging to remove the in-cylinder burnt gases and to fill the cylinder with fresh charge, performed at the same time is one of the major challenges, as losses of fresh air and fuel towards the exhaust line should be avoided when operating a lambda = 1 concept necessary for a 3-way catalyst aftertreatment system. A prior study [1] of different gas exchange designs for two-stroke engines concludes that two possible concepts cover this purpose. In this paper, 3D-CFD simulation is used to compare these two different scavenging concepts, a uniflow and a loop scavenging type with control elements for the gas exchange process. As boundary conditions, it is assumed that both concept types have nearly the same displacement, are used
Sturm, Stefan, Lang, Michael, Schmidt, Stephan
Analysis of Cycle-to-Cycle Variation in a Port Injection Gasoline Engine by Simultaneous Measurement of Time Resolved PIV and PLIF2019-32-05521/24/2020
Cycle-to-cycle variation (CCV) of combustion in low load operation is a factor that may cause various problems in engine operation. Variable valve timing and variable ignition timing are commonly used as a means to reduce this variation. However, due to mountability and cost constraints, these methods are not feasible for use in motorcycle engines. Therefore, development of an engine with minimal CCV without utilizing complicated mechanisms or electronic control is required. CCV of combustion may be caused by fluctuations in in-cylinder flow, air-fuel mixture, temperature, residual gas and ignition energy. In this study, the relationship between CCV of combustion, in-cylinder flow fluctuation and air-fuel mixture fluctuation was the primary focus. In order to evaluate in-cylinder flow fluctuation, Time Resolved Particle Image Velocimetry (TR-PIV) technique was utilized. In addition, Planar Laser Induced Fluorescence (PLIF) technique was used to measure spatial distribution of the
HARAMIISHI, Santa, WATANABE, Takahiro, IIDA, Minoru, HOKIMOTO, Satoshi, KUBOYAMA, Tatsuya, MORIYOSHI, Yasuo
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