Browse Topic: Manifolds

Items (864)

8/11/2021

This slash document collects general reference material related to gaseous oxygen system flow requirements and sizing calculations. This document will assist oxygen system equipment designers and operators to establish systems and equipment requirements. The document consists of charts, tables, system schematics, system requirements, and sample calculations for system sizing.

A-10 Aircraft Oxygen Equipment Committee

7.0.101 - A New Image De-hazing Method for Safety Critical ADAS Applications

SAE-PP-002772/4/2021

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.

Lname, Fname

6.0.116 - Development of 6 Years Old Child Virtual Model by Automatic Scaling

SAE-PP-002712/4/2021

Traffic accidents cause one of the highest numbers of severe injuries in the whole population. The numbers of deaths or seriously injured citizens prove that traffic accidents and their consequences are still a serious problem to be solved. A lot of effort is devoted to both passive and active safety systems development. The transportation standards usually define safety requirements by regulations (e.g. ECE-R94, 96/79/EC and ECE-R95, 96/27/EC in Europe) with specific dummies for children to be used. The dummies include hardware sensors for monitoring accelerations, loads and other signals and each dummy is developed for a specific scenario, but there are limitations of these dummies, such as only a specific age or calibration just for a specific test. Taking into account that the consequence of a traffic accident is highly influenced by the stature of the body, virtual human body models, including those for children, start to play a significant role because they can be scaled or even personalized towards a particular population or even a particular person. The paper contributes to the field of vehicle safety technology concerning child restraint systems development, assessment and optimization with a virtual numerical approach. The goal of the paper is to exploit the previously developed scaling algorithm to create a virtual model of a six-year-old (6YO) child and to compare its response to the virtual dummy used for child safety in order to propose an automatic scaling process for a population-based vehicle safety assessment. The automatic scaling algorithm developing virtual human body models for a given age and gender is used to create the virtual 6YO child model. The algorithm scales body dimensions and particular segments' mass and the flexibility of the body is driven by flexindex and stiffness scaling. The performance of the automatically developed virtual 6YO child model was tested in frontal and lateral directions. The frontal response was tested with a standard sled test simulation using the standardized AAMA pulse in the frontal direction. The lateral response was tested with a side barrier impact test. The results of both tests were compared to the validated virtual Q6 Child Dummy FE model. The paper shows good performance of the automatic scaling process for developing 6YO virtual model for safety assessment. The automatically developed 6YO child model corresponds well from both the anthropological point of view and performance point of view to the existing validated dummy model.

Mutagaana, Festo

6.0.101 - Piston Sealing System Structure Design for Automobile's Lightweight Auto-Transmission

SAE-PP-002572/4/2021

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

2.0.101 - Experimental Study of cooling of Continuously Variable Transmission (CVT) in Scooter

SAE-PP-002102/1/2021

The continuously variable transmission (CVT), which was conceptualized more than 500 years ago, is just now beginning to replace traditional transmissions in some automobiles. It is mostly used in scooter transmission. Engine power is transmitted to wheel through belt drive between two pulleys. The diameter of belt contact with pulley can change continuously and hence provide infinite gear ratios between driver and driven shafts. This technology leads to a smoother ride of vehicle. Heat is generated inside CVT due to friction between drive belt and clutch pulley. Amount of heat generated is even more due to clutch slippage during acceleration and deceleration. This will affect the service life of CVT components such as front movable drive (FMD), clutch pulley, clutch outer, and belt. In scooters generally, air cooling is preferred over liquid cooling. Cooling is achieved by incorporating centrifugal fan inside CVT housing. For better durability/service life, the degree of heat generated at CVT components should be minimal. The objective of this work is to identify the parameters causing change in temperature of CVT components and to evaluate its surface temperature in accordance with changed parameters. With reference to this, experiments were conducted with requisite design modification inside CVT housing, which enhances cooling effect. Amongst, variables determining air flow rate, are studied and their effect on temperature inside CVT housing is observed experimentally. Keeping the previous variables unaltered, further design modifications related to air flow pattern are done and cumulative effect of all variables is observed. Experiments were performed on an 110cc scooter engine by following customer driving pattern on chassis dynamometer. Results showed that design modifications intended for better cooling effect, has brought down temperature at CVT components. So, desired cooling effect is observed inside CVT housing imparting better service life of CVT components.

Mutagaana, Festo

Functionality Analysis of Thermoplastic Composite Material to Design Engine Components

2020-01-07744/14/2020

Developing of innovative technologies and materials to meet the requirements of environmental legislation on vehicle emissions has paramount importance for researchers and industries. Therefore, improvement of engine efficiency and fuel saving of modern internal combustion engines (ICEs) is one of the key factors, together with the weight reduction. Thermoplastic composite materials might be one of the alternative materials to be employed to produce engine components to achieve these goals as their properties can be engineered to meet application requirements. Unidirectional carbon fiber reinforced PolyEtherImide (CF/PEI) thermoplastic composite is used to design engine connecting rod and wrist pin, applying commercial engine data and geometries. The current study is focused on some elements of the crank mechanism as the weight reduction of these elements affects not only the curb weight of the engine but the overall structure. As a matter of fact, by reducing the reciprocating mass, alternate forces will be reduced and hence the size of the structural elements. Also, other elements of the engine can be designed for lightweighting, but the crank mechanism elements maximize the effects, by reducing both loads and weight. Finite element analysis (FEM) has been conducted for proper stress analysis and accordingly examine the design and parts functionalities. FEM analysis is performed using Altair HyperMesh for mesh optimization to conduct stress analysis of standard engine components made of steel and to redesign the parts using thermoplastic material to sustain the loads and stresses. Then the design modification has been considered to reduce loads and weight without parts performance interruption under service.

Razavykia, Abbas, Delprete, Cristiana, Rosso, Carlo, Baldissera, Paolo

Effect of Different Geometrical Changes in the Intake Manifold of a DI Diesel Engine Fueled with Biodiesel-Diesel Blends

2020-01-03464/14/2020

One of the major challenges of biodiesel run diesel engines is poor mixture formation. This problem can be overcome by inducing the turbulence into the engine cylinder, thereby a proper mixing of air-fuel occurs. In this study, an attempt was made to assess the engine behavior in terms of its combustion, performance and emission characteristics by replacing the normal intake manifold with the internally buttress threaded manifold, which is designated as IBTM throughout the manuscript. This investigation was further carried out to run the engine with suitable blends such as WCOME10 (10% of WCOME + 90% diesel) and WCOME20 (20% of WCOME + 80% diesel). Based on the results obtained in this study, IBTM exhibits a higher BTE of about by 2.8% for WCOME20-b than that of diesel operation (at normal intake). At the same time, the carbon monoxide (CO), hydrocarbon (HC) and smoke emissions were decreased by about 1%, 30.3%, and 20.4% respectively, whereas, NOx emissions were increased by about 21.9% for IBTM run on same blend (WCOME20-b) on compared to the normal intake manifold when fueled with diesel. Similarly, for WCOME20-b, the delay period decreased by 3°CA than that of diesel operation. At all the cases of this study, by inducing the turbulence (or) with IBTM, an increase in HRR was noticed, which showed an improvement in the amount of work developed.

Reddy, Niklesh P., Khayum, Naseem, Uppara, Devendra

Leading Women in Engineering & Science: Sarah Charette, Product Manager

TBMG-362593/1/2020

Rework of an in-line two-cylinder engine for the application in Formula Student

2019-32-05321/24/2020

Formula Student is an international design competition, where students all over the world develop, design and build their own race car and afterwards compete with each other at different disciplines at events worldwide. The development process includes every module of the race car and the team of joanneum racing graz has focused on the powertrain since the beginning. The following paper contains an overview of the reworking process of an in-line two-cylinder engine for the application in Formula Student. The intention was to increase the BMEP and at the same time reach a desired power/weight ratio of the engine. The process of selecting the most appropriate turbocharger by means of experimental testing on an engine dynamometer, as well as its optimization by means of numerical simulation, is outlined. Subsequently, the paper discusses the challenges regarding valve timing and finding the best trade-off between power and residual gas with the help of 1D-simulations. The necessary implementation of an intercooler and its efficiency optimization is also addressed. Finally, the calibration and optimization of the setup on the engine test bed is presented. After the selection of the most suitable turbocharger for the engine and the reworking of its compressor side, it was possible to achieve a maximum boost pressure of 2.76 bar absolute. Charge air cooling and closed loop boost control guaranteed fast boost pressure build up. Together with the optimized cam timing, which reduced residual gas, and an increased compression ratio, the overall torque output of the engine resulted in 135 Nm at 4000 rpm and a maximum power of 63 kW at 6000 to 6500 rpm. The overall target of increasing the BMEP of the selected engine and at the same time achieving a lower power/weight ratio than the previous engine (FS133) was accomplished with a final value of 0.81 kW/kg.

Feigl B.Sc, Michael, Rößmann B.Sc, Dominik, Michael Trzesniowski, FH-Prof. DI

CI Methanol and Ethanol combustion using ignition improver

2019-01-223212/19/2019

To act on global warming, CO2 emissions must be reduced. This will require a reduction in the use of fossil fuels for transportation. Because of the large quantities of fossil fuels used in transportation, sources of renewable fuels other than biomass will have to be explored, such as electrofuels synthesized from CO2 using renewable electricity. Potential electrofuels include methanol and ethanol, which have shown promising results in SI engines. However, their low cetane numbers make these fuels unsuitable for CI engines because of their poor auto-ignition qualities. The main objective of this study was to evaluate the viability of using methanol and ethanol in CI engines at compression ratios of 16.7 and 20 with a pilot-main injection strategy in the PPC/CI regime. Single cylinder engine tests on a heavy duty engine were performed under medium load conditions (1262 rpm and 172 Nm). The higher compression ratio generated significantly better indicated thermal efficiencies, lower brake-specific NOx emissions, and less combustion noise. Soot emissions were well below current tailpipe emission limits in all cases.

Michael, Saccullo, Timothy, Benham, Ingemar, Denbratt, Bengt, Johansson

Two-Degree-of-Freedom Controller Design for Diesel Engine Airpath System Considering Dynamics of Turbocharger and Manifolds

2019-01-232112/19/2019

We developed a two-degree-of-freedom (2-DOF) control system for a diesel engine airpath system. First, a physical airpath model of the diesel engine was developed, followed by a nonlinear feedforward controller developed based on the inverse characteristics of the developed physical model. The dynamics of turbocharger and manifolds were considered in the feedforward controller to improve the transient response. The feedback controller was designed by H∞ control theory considering plant nonlinearities as uncertainties. The feedforward and feedback controllers were implemented as a 2-DOF freedom control scheme. The effectiveness of the proposed method was evaluated by conducting simulation and experiment.

Hirata, Mitsuo, Hayashi, Tomofumi, Asahi, Teruhiko, Takahashi, Motoki, Yamazaki, Yudai, Kaneko, Shigehiko

More sting for the STINGRAY

19AUTP11_0211/1/2019

GM Propulsion engineers elevate the evergreen small-block V8 to new heights for its mid-engine Corvette mission. Instead of heaving decades of small-block V8 expertise out the window, GM Propulsion engineers led by chief engineer Jordan Lee leveraged past success to create a new-for-2020 V8. Known as the LT2, the 6.2-L V8 gives Chevy's all-new, eighth-generation 2020 Corvette more power (the most yet in the base Stingray), stirring response, and competitive fuel efficiency compared with the outgoing C7. And the small-block, with its single camshaft in block and two valves per cylinder, remains unmatched versus its rivals in three key metrics: bill of material, package efficiency, and the power-per-dollar quotient. It's the payoff for 65 years of continuously refining (and never giving up on) a brilliant original design.

Sherman, Don

Effect of Injector Cone Angle and NTP on Performance and Emissions of BS6 Engine

2019-28-010810/11/2019

The combustion phenomenon of diesel engines has got a very major impact on the performance and exhaust emission levels. Several important factors like engine components design, combustion chamber design, Exhaust gas recirculation, exhaust after treatments systems, engine operating parameters etc. decide the quality of combustion. The role of fuel injector is crucial on achieving the desired engine performance and emissions. Efficient combustion depends on the quantity of fuel injected, penetration, atomization and optimum timing of injection. The nozzle through flow, cone angle, no of sprays and nozzle tip penetration are the factors which lead to the selection of perfect injector for a given engine. This paper focusses on the selection of the best fit injector suiting the BS6 application on evaluating the performance and emission characteristics. Injectors used were with varying cone angles and NTP. The nozzle tip protrusion of the injectors were varied by changing the sealing washer thickness. With all the above injector configurations, the performance and emission were thoroughly analysed at every level. Final confirmation of the configuration was selected based on the Power & Torque, Fuel consumption, smoke, exhaust temperatures.

Muthusamy, Anbarasu, Shangar Ramani, Vagesh, Sinha, Pranav Kumar

A Comprehensive Study on Euro 6 Turbocharger Selections and Its Deterioration with Closed Crank-Case Ventilation in Heavy Commercial Vehicles

2019-24-00619/9/2019

Euro 6 emission norms are getting implemented in India from April 2020 and it is being viewed as one of the greatest challenges ever faced by the Indian automotive industry. In order to achieve such stringent emission norms a good strategy will be to optimize the engine out emission through in cylinder emission control techniques and a right sized after treatment system has to be used for this optimized engine. There exist several factors and trade-off between these should be established for in cylinder optimization of emissions. Since the turbocharger plays an apex role in controlling both the performance and engine out emissions of a CI engine, turbocharger selection is a crucial step in the development of new generation of Euro 6 engines in India. Such engines are equipped with additional actuators such as Intake Throttle Valve and Exhaust Throttle Valve and combination of these flap operations with turbocharger output plays a prominent role in controlling performance and emission. This study focusses on the use of different AVU (Air Valve Unit) controlled waste gate turbochargers from different suppliers and how it’s matched with the engine performance requirements. Hindrances such as fluctuations in boost pressure due to the waste gate operational inconsistency and deterioration of turbo efficiency due to closed (positive) crankcase ventilation over time were faced during evaluation, and the solution to such problems are also mentioned in this study. It was found that the drop in efficiency of compressor can be as high as 5 - 10% without a proper oil separator set up and is verified with back to back tests.

Mohan, Aravind, Jaliwala, Juzer, Bhagat, Kunaal, Patchappalam, Kumar

Build IIoT Networks with Smart Control and HMI Software

TBMG-348798/1/2019

Programmable automation controllers (PACs) play the primary role in IIoT systems. Also referred to as machine controllers, PACs provide a centralized architecture; they act as the central programmable logic controller (PLC) as well as motion, vision, pneumatic, hydraulic controller, and even embedded human-machine interface (HMI) or visualization (Figure 1). The benefit of the PAC approach is that the program does not need to share tags between devices due to components being part of the same device and using the same logic. This facilitates IIoT capabilities and reduces programming time. This is critical to IIoT as it allows the flow of accurate, actionable data to easily transfer within the machine and out to the user or server to make critical decisions with that data.

An Exploratory Look at an Aggressive Miller Cycle for High BMEP Heavy-Duty Diesel Engines

2019-01-02314/2/2019

Through aggressive application of the Miller Cycle, using two-stage turbocharging, medium speed diesel marine and stationary power engines are demonstrating over 30 bar rated power BMEP, and over 50 percent brake thermal efficiency. The objective of this work was to use engine cycle simulation to assess the degree to which the aggressive application of the Miller Cycle could be scaled to displacements and speeds more typical of medium and heavy truck engines. A 9.2 liter six-cylinder diesel engine was modeled. Without increasing the peak cylinder pressure, improved efficiency and increased BMEP was demonstrated. The level of improvement was highly dependent on turbocharger efficiency - perhaps the most difficult parameter to scale from the larger engines. At 1600 rpm, and a combined turbocharger efficiency of 61 percent, the baseline BMEP of 24 bar was increased to over 26 bar, with a two percent fuel consumption improvement. As turbocharger combined efficiency increased, to over 75 percent as seen in large, medium speed engines, over 29 bar BMEP was achieved, with over six percent fuel consumption improvement. Similar results were seen at 1200 rpm, with a maximum BMEP of over 34 bar, and greater than two percent fuel consumption improvement, at a turbocharger combined efficiency of 61 percent. Application considerations including speed and load range, and emission constraints are discussed.

Hoag, Kevin L.

Analysis of the Impact of Production Lubricant Composition and Fuel Dilution on Stochastic Pre-Ignition in Turbocharged, Direct-Injection Gasoline Engines

2019-01-02564/2/2019

The occurrence of abnormal combustion events leading to high peak pressures and severe knock can be considered to be one of the main challenges for modern turbocharged, direct-injected gasoline engines. These abnormal combustion events have been referred to as Stochastic Pre-Ignition (SPI) or Low-Speed Pre-Ignition (LSPI). The events are characterized by an undesired, early start of combustion of the cylinder charge which occurs before or in parallel to the intended flame kernel development from the spark plug. Early SPI events can subsequently lead to violent auto-ignitions that are often referred to as Mega- or Super-Knock. These heavy knock events lead to strong pressure oscillations which can destroy production engines within a few occurrences. SPI occurs mainly at low engine speed and high engine load, thus limiting the engine operating area that is in particular important to achieve good drivability in downsized engines. Recent experimental SPI studies have linked this phenomenon strongly to engine oils. While numerous studies have been published using target blended oils, the presented study focuses on the impact of lubricants with production level formulations on SPI event occurrence. The utilized test engine is a production, turbocharged, direct-injection gasoline (GTDI) engine with a homogeneous common rail high pressure injection system and side mounted multi-hole injectors. All experiments were conducted on a steady state engine test bench with intake air, coolant, oil and fuel conditioning. The engine was equipped with a prototype engine controller that allowed negating the influence of vehicle, knock mitigation or balancing algorithms on combustion properties. 11 market relevant production engine oils for sale in the US in 2017 were analyzed regarding their composition using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). All 11 oils were then tested for their impact on SPI occurrence, severity and characteristics. The experimental results were subsequently correlated to the oil analysis results. In addition, one oil was analyzed regarding the impact of fuel dilution and ageing on SPI occurrence using the same test setup.

Haenel, Patrick, de Bruijn, Rob, Tomazic, Dean, Kleeberg, Henning

Evaluation of Knock Intensity and Knock-Limited Thermal Efficiency of Different Combustion Chambers in Stoichiometric Operation LNG Engine

2019-01-11374/2/2019

Liquefied natural gas (LNG) engine could provide both reduced operating cost and reduction of greenhouse gas (GHG) emissions. Stoichiometric operation with EGR and the three-way catalyst has become a potential approach for commercial LNG engines to meet the Euro VI emissions legislation. In the current study, numerical investigations on the knocking tendency of several combustion chambers with different geometries and corresponding performances were conducted using CONVERGE CFD code with G-equation flame propagation model coupled with a reduced natural gas chemical kinetic mechanism. The results showed that the CFD modeling approach could predict the knock phenomenon in LNG engines reasonably well under different thermodynamic and flow field conditions. The predicted threshold between “no knock” and “knock” conditions was found to be in good agreement with experimental results, which means it provides a valid way to estimate the capability of knock suppression and knock-limited thermal efficiency for the design and optimization of LNG combustion system. Based on the validated CFD model, the effects of combustion chamber structures on turbulent flow and combustion process were discussed. The results showed that lower mean flow velocity in the spark plug region and higher turbulent kinetic energy in the center of the combustion chamber and near the spark plug can be obtained with a shallow re-entrant chamber geometry at the time of ignition and during the early combustion stage, which could effectively promote the initial flame propagation. However, the knock propensity is also higher compared to other combustion chamber geometries, mainly due to the preheating of the flame front in the squish crevices and the suppression of flame propagation to the bottom of the combustion chamber, which limits the thermal efficiency improvement. In addition, it’s found that the thermal efficiency of the current LNG engine with aluminum piston is restricted by both the knock and durable peak in-cylinder pressure (mechanical strength). Therefore, it’s essential to develop effective combustion and knock control strategies under higher peak in-cylinder pressure conditions (with higher CR steel piston) to further improve the thermal efficiency of stoichiometric LNG engine.

Zhao, Xumin, Wang, Hu, Zheng, Zunqing, Yao, Mingfa, Sheng, Li, Zhu, Zan

Numerical Study of Intake Manifold Water Injection on Characteristics of Combustion and Emissions in a Heavy-Duty Natural Gas Engine

2019-01-05624/2/2019

The performances of heavy-duty natural gas engines have been limited by combustion temperature and NOx emissions for a long time. Recently, water injection technology has been widely considered as a technical solution in reducing fuel consumption and emissions simultaneously in both gasoline and diesel engines. This paper focuses on the impacts of intake manifold water injection on characteristics of combustion and emissions in a natural gas heavy-duty engine through numerical methods. A computational model was setup and validated with experimental data of pressure traces in a CFD software coupled with detailed chemical kinetics. The simulation was mainly carried out in low-speed and full-load conditions, and knock level was also measured and calculated by maximum amplitude of pressure oscillations (MAPO). The results show that the quantity of injected water does not have a negative effect on water spray and film at an appropriate position, but an increase in the quantity of injected water leads to a negative effect on charging efficiency and a decrease in IMEP. However, the knock in natural gas engines can be suppressed after water injected into intake manifold. The simulation results illustrate that, at the same MAPO index, the spark timing can be advanced from 16.3 °CA BTDC to 22.3 °CA BTDC while keeping a relative low level of NOx emissions, and the indicated thermal efficiency increases by 0.6% when the water-to-natural-gas mass ratio is 0.5. Intake manifold water injection technology is also an efficient way to reduce NOx emissions in natural gas engines. Compared with the original emissions, a decrease of 40% in NOx emissions can be achieved under a higher mass ratio of water to natural gas, at 0.6. These indicative results can be helpful for the application of water injection technology in practical heavy-duty natural gas engines to reduce emissions and increase thermal efficiency in the future.

Wu, Jingtao, Kang, Zhe, Deng, Jun, Wu, Zhijun, Li, Liguang, Li, Zhilong, Shu, Mingyu, Liang, Heping

CFD Simulation of Metal and Optical Configuration of a Heavy-Duty CI Engine Converted to SI Natural Gas. Part 2: In-Cylinder Flow and Emissions

2019-01-00031/15/2019

Internal combustion diesel engines with optical access (a.k.a. optical engines) increase the fundamental understanding of combustion phenomena. However, optical access requirements result in most optical engines having a different in-cylinder geometry compared with the conventional diesel engine, such as a flat bowl-in-piston combustion chamber. This study investigated the effect of the bowl geometry on the flow motion and emissions inside a conventional heavy-duty direct-injection diesel engine that can operate in both metal and optical-access configurations. This engine was converted to natural-gas spark-ignition operation by replacing the fuel injector with a spark plug and adding a low-pressure gas injector in the intake manifold for fuel delivery, then operated at steady-state lean-burn conditions. A 3D CFD model based on the experimental data predicted that the different bowl geometry did not significantly affect in-cylinder emissions distribution. In addition, while in-cylinder flow motion was similar for both engine configurations, the different combustion chamber geometry affected the combustion-induced flow motion. Similar turbulence-generating mechanisms for engines with or without optical access show promise for optical investigations of cold-flow turbulence measurements representative of heavy-duty diesel engines converted to natural-gas spark-ignition operation.

Liu, Jinlong, Dumitrescu, Cosmin

Fuel & Lubricant Effects on Stochastic Preignition

2019-01-00381/15/2019

In this multi-phase study, fuel and lubricant effects on stochastic preignition (SPI) were examined. First, the behavior of fuels for which SPI data had previously been collected were characterized in terms of their combustion and emissions behavior, and correlations between these characteristics and their SPI behavior were examined. Second, new SPI data was collected for a matrix of fuels that was constructed to test and confirm hypotheses that resulted from interpretation of the earlier data in the study and from data in open literature. Specifically, the extent to which the presence of heavy components in the fuel affected SPI propensity, and the extent to which flame initiation propensity affected SPI propensity, were examined. Finally, the interaction of fuels with lubricants expected to exhibit a range of SPI propensities was examined. Although this final dataset did not yield conclusive results, it suggests that additional factors such as engine condition can have a very significant effect on SPI propensity. The main findings of the study are that lower volatility fuel components appear to affect the propensity of the fuel to create initiation events (which could be fuel-oil droplets or deposit breakoff) that can lead to SPI, and further that the ease by which a flame can be established in the bulk mixture correlates to SPI tendency when the initiation event tendency is fixed. The study also showed that neither soot-forming tendency of a fuel nor the fuel’s antiknock quality necessarily correlate to SPI tendency.

Costanzo, Vincent S., Yu, Xin, Chapman, Elana, Davis, Richard, Haenel, Patrick

The Rotating Liner Engine (RLE) Diesel Prototype: Preliminary Testing

2019-01-00841/15/2019

The Rotating Liner Engine (RLE) concept is a design concept for internal combustion engines, where the cylinder liner rotates at a surface speed of 2-4 m/s in order to assist piston ring lubrication. Specifically, we have evidence from prior art and from our own research that the above rotation has the potential of eliminating the metal-to-metal contact/boundary friction that exists close to the piston reversal areas. This frictional source becomes a significant energy loss, especially in the compression/expansion part of the cycle, when the gas pressure that loads the piston rings and skirts is high. This paper describes the Diesel RLE prototype constructed from a Cummins 4BT and the preliminary observations from initial low load testing. The critical technical challenge, namely the rotating liner face seal, appears to be operating with negligible gas leakage and within the hydrodynamic lubrication regime for the loads tested (peak cylinder pressures of the order of 80 bar).

Dardalis, Dimitrios, Hall, Matthew, Matthews, Ron, Basu, Amiyo, Ozel, Tayyar

Neural Network Based Throttle Actuator Model for Controller

2019-26-02471/9/2019

HiL is a closed loop validation setup widely used in the validation of real-time control systems. In the existing HiL setup, the ECUs to be tested are real while the remaining vehicle is modelled as plant model using Simulink. But some actuators like throttle valve, waste-gate valve, injectors, etc. are not modelled as plant model. Since these actuators exhibit hard nonlinearity, it is difficult to design accurate models of these actuators. So these actuators are connected to the HiL as real hardware components. But the major drawbacks of using real hardware components are: they need more space and they are costly. Hence, in this work, a real-time throttle actuator model for the controller is proposed. A throttle actuator contains a DC motor and a spring loaded flap. To create an accurate ODE based model of the throttle actuator, parameter identification of each component of the throttle actuator needs to be done separately by dismantling the actuator. This approach needs more effort and time. Hence, a robust non-linear learning based model is proposed. The learning based model uses neural network which is trained using input and output data across throttle actuator. To train the model, a new parameter estimation algorithm is also proposed. The proposed parameter estimation process is based on meta-heuristic simulated annealing search algorithm. The proposed model is trained by taking input and output data across the throttle actuator from HiL. The trained model is then validated using WLTP dataset and is found to be working satisfactorily. Hence, the model is planned to be tested real-time on HiL in the next step. In this work, the parameter estimation process is presented.

Khasnabish, Neilay, Suggu, Dhanunjaya, Koppad, Ashwini

An Investigation with Mechanical Supercharging as Boosting Solution on Less than 0.5 Liter Single Cylinder Diesel Engine towards Bharat Stage VI Emission Development

2019-26-01521/9/2019

Small single & two cylinder diesel engines, still have primitive technical design features and extensively used in India and various Asian countries to power small and light motor vehicles viz., three wheelers, light duty four wheelers. These vehicles have become inevitable for the transport for both urban and rural areas. Vehicles with small single & two cylinder engines have high market demand in commercial transport due to restrictions on entry of Heavy Commercial Vehicles (HCV) in congested cities roads. Due to ever rising market demand for higher power and torque requirement along with better fuel economy, vehicle manufacturer are developing high Brake Mean Effective Pressure (BMEP) engines or replacing single cylinder engine by two cylinder engine, similarly two cylinder engine by three cylinder engines. Further, these engines should meet the present and forthcoming stringent emission limits. Single cylinder and two cylinder small diesel engines are widely used in various applications like Light Commercial Vehicle (LCV), power generation, three wheelers, agricultural machines and small house-hold applications in India as well as other Asian countries. Therefore simple mechanically controlled components are used for these engines which make them simple in operation with low maintenance and cost effective. Several studies & research work so far conducted on these small single engine have revealed that, successful & economically acceptable turbocharging of single cylinder diesel engine is not yet achieved. This is due to its phase mismatch between intake and exhaust stroke timings, long gap between two exhaust stroke and continuous flow of exhaust gas to drive the turbine wheel efficiently. This paper addresses the problems through mechanical supercharging. For this research work, a small 0.4 liter, three wheeler (3W), naturally aspirated, air-cooled, single cylinder DI diesel engine, equipped with mechanical fuel injection system, is used. A roots type supercharger, driven mechanically from a drive pulley directly mounted on crankshaft, is used for boosting the engine. Experiments were conducted with various engine parameters, settings and step-up ratios of the drive pulley. The results show an observed increase in engine power more than 20 % throughout the full load curve and favorable emission levels with respect to the base BS III compliant single cylinder engine. The experimental outcomes and reviews which are required to arrive at adequate boosting to enhance the performance & emissions of the engine are reported.

Bhat, Prasanna, Pawar, Narendra, Narwade, Dadarao, Nalawade, Santosh, Gayen, Hirak Jyoti, Marathe, Neelkanth, Chopane, Sanjay Parshuram

Evaluation and Selection of Turbocharger Meeting BS6 Emission Norms for 1.99l Engine

2019-26-00581/9/2019

Migration to BS6 emission norms from BS4 levels involves strenuous efforts involving advanced technology and higher cost. The challenging part is on achieving the stringent emission norms without compromising the engine fuel economy, performance and NVH factors. Selection of hardware and attaining an optimal behaviour is therefore vital. This article focuses on the evaluation of three different configuration of turbochargers for the same engine to meet the BS6 emission norms and performance. The turbocharger samples used measure the same compressor diameter with varying trim ratios. Simulation and testing of turbochargers ensured positive results for confirmation of the system. Parameters like low speed torque, smoke and compressor efficiency were evaluated and analysed for all configurations. The safe limits of surge and choke regions of all the compressors were also studied and verified. Influence of varying compressor trim on the performance and emissions were examined thoroughly in this work. Full throttle performance and 14 mode test for emissions concluded that the performance and emission parameters were satisfactory with all the turbochargers. However, 4778 Turbocharger gives best Full load performance than other Turbochargers and meeting the 14 mode emission target and it’s finally selected for the engine application.

J, Giftson, Muthusamy, Anbarasu, Shangar Ramani, Vagesh, Bhachchu, Gurtej, R, Sivasubramamanian, Anand, M, K, Arun

Technology to Achieve Engine Efficacy: Optimized Intake System

2019-26-00521/9/2019

In the era of sustainable engines where the need of high power, torque, engine life is increasing while eliminating BSFC and emission concerns, the variable length intake manifold system helps to provide optimized intake system. The research consists of adopting continuous variable length intake manifold on diesel engines where compression and suction waves provide better swirl and pressurization methodology. The continuous varying intake manifold helps to provide better volumetric efficiency by more than 100% as constructive waves provide improved swirling which leads to reducing detonation and better combustion. The manifold path changes with every range of rpm through operating butterfly valve, which also guides air intake path according to engine load. The air flow is increased at low rpm bypassing the intake air from the long and narrow path to increase low-speed torque. The top end power is increased at high rpm by passing intake air through short and long paths which supplies the great amount of air without any restriction. The variable length intake manifold reduces emission in the diesel engine as it provides pressurized air flow leading to Helmholtz resonance which improves combustion. The total hydrocarbons, CO is reduced while increasing small amount of NOX along with the decrease in BSFC. The optimized torque is achieved with higher cross section manifold at low rpm and with lower cross section at higher rpm, this led to drawback of any multi stage variable intake manifold. The continuous variable intake manifold helps to provide the optimized intake path to provide maximum power and torque. The slider mechanism empowers to attain continuous varying length which removes the limitations of multiple paths operated by multiple valves.

Sharma, Prashant, Singh, Aditya Pratap, Sharma, Vijay, Rai, Vivek

Modeling of Quasi-Steady State Heat Transfer Phenomena with the Consideration of Backflow Gas Effect at Intake Manifold of IC Engines and Its Numerical Analyses on 1-D Engine Simulation

2018-32-002910/30/2018

An empirical equation was developed for modeling the heat transfer phenomena taking place in an intake manifold which included the backflow gas effect. In literature, heat transfer phenomenon at intake system is modeled based on steady flow assumptions by Colburn analogy. Previously, authors developed an equation with the introduction of Graetz and Strouhal numbers, using a port model experimental setup. In this study, to further improve the empirical equation, real engine experiments were conducted where pressure ratio between the intake manifold and engine cylinder were added along with Reynolds number to characterize the backflow gas effect on intake air temperature. Compared to the experimental data, maximum and average errors of intake air temperature estimated from the new empirical equation were found to be 2.9% and 0.9%, respectively. Furthermore, Colburn analogy and suggested empirical equation were consecutively implemented to 1-D engine simulation software on gasoline and diesel engine setups. Naturally aspirated gasoline engine simulations revealed the importance of the backflow gas effect in line with the real engine experiments. Maximum and average temperature differences between the Colburn analogy and suggested equation showed 36.0 K and 28.7 K, respectively. In turbocharged diesel engine simulations, intake air temperature’s effect on auto ignition timing was analyzed. At engine speed of 2250 rpm, in-cylinder air temperature difference at IVC was found to be 5.8 K. This difference corresponded to an advanced auto-ignition timing by 1.15 deg. CA, which could be interpreted an estimated reduction of CO2 gas by 0.28%.

Yilmaz, Emir, Ichiyanagi, Mitsuhisa, Suzuki, Takashi

Dual-volute SALUTE!

18AUTP10_1810/1/2018

BorgWarner's new twist in turbocharging helps GM's new L3B gasoline four deliver V6-beating power and torque, with diesel-like fuel efficiency, in full-size pickup trucks. GM's all-new 2.7-L L3B was designed for truck use, with a wealth of advanced features (see https://www.sae.org/news/2018/05/gm-2.7-l-i-4-revealed). The result is 9% more power and 14% more torque than GM's incumbent LV3 4.3-L V6. Teamed with the 8L90 8-speed Hydra-Matic transmission, the L3B turbo four is the base engine for 2019 Chevy Silverados in LT and RST trim and also is offered in the 2019 GMC Sierra. Engineering a boosted I4 for full-size pickups' broad duty cycle was no mean feat. Such engines provide impressive economy during steady-state cruising in top gear and generate ample thrust under load once the revs and boost are up. The challenge is in the transition between those operating modes-when the engine must leap into action as the throttle is quickly moved from barely open to WOT.

Sherman, Don

Study of Swirl Ratio on Mixture Preparation with a Swirl Control Valve in a Diesel Engine

2018-01-17909/10/2018

Downsizing as a main-stream technology was widely used for design of future diesel engines in order to meet the increasingly stringent demands of emissions regulation and reduction of CO2 production. Design of intake system faces a considerable challenge accordingly. Discharge coefficient and swirl ratio as two main factors of intake port design have been widely investigated by researchers. However, these two parameters indicate a trade-off relationship. Therefore, it is difficult for a classical intake system to achieve a good balance between sufficient air charge and decent air-fuel radial mixing quality. A 1 L twin-intake-port single-cylinder diesel engine was studied in this paper. A swirl control valve designed to adjust the effective flow area of the filling port, was installed between the intake manifold and the intake filling port in order to achieve variation of swirl ratio. And there is no control valve for the intake spiral port. Influence of varied angles of the swirl control valve on the discharge coefficient and the swirl ratio of intake ports were firstly investigated on a steady flow rig. Then Particle Image Velocimetry (PIV) technique was used to visualize the in-cylinder swirl motion. Besides, CFD method was used to evaluate the effects of varied valve angles on the following air-fuel mixing process in the cylinder. The results show that CFD reveals the in-cylinder flow structure and the location of swirl center similar with the 3D-PIV test results. With the increase of swirl ratio at IVC from 0.57 to 2.05, air-spray interaction in the circumferential direction is strengthened in the terms of mixture preparation. Strong swirl motion accelerates the heat release during the premixed combustion stage, which results in an advancement of CA50 and a reduction of combustion duration. High swirl motion intensity makes a positive effect on the increase of accumulated heat release under the same air flow mass rate.

Li, Haiying, Wang, Lei, Wang, Kun, Zhu, Weiqing, Li, Yufeng, Jiang, Li

Simulation of Intake Manifold Water Injection in a Heavy Duty Natural Gas Engine for Performance and Emissions Enhancement

2018-01-16539/10/2018

The present work discusses the effects of intake manifold water injection in a six-cylinder heavy duty natural gas (NG) engine through one-dimensional simulation. The numerical study was carried out based on GT-Power under different engine working conditions. The established simulation model was firstly calibrated in detail through the whole engine speed sweep under full load conditions before the model of intake manifold water injector was involved, and the calibration was based on experimental data. The intake manifold water injection mass was controlled through adjustment of intake water/gas (water/natural gas) ratio, a water/gas ratio swept from 0 to 4 was selected to investigate the effects of intake manifold water injection on engine performance and emissions characteristics. On the other hand, the enhancement potential of intake manifold water injection in heavy duty NG engine under lean and stoichiometric condition was also investigated by the alteration of air-fuel ratio. The calculation results demonstrated that in considering maximum performance enhancement strategy preferentially, the engine performance characteristics was increased around 3% under lean condition while 7%-10% at stoichiometric condition, with a drastic NOX emissions reduction capability around 70%-80%. When took minimum NOX emissions as a primary consideration for water injection strategy, over 90% of NOX emissions at lean condition and 80% of NOX emissions at stoichiometric condition could be eliminated with performance characteristics and BSFC deterioration less than 10%. To achieve optimized engine performance and emissions characteristics simultaneously, the optimum engine control strategy with intake manifold water injection could be attained through an advanced spark timing while maintaining water/gas ratio the same as the minimum NOX emissions strategy.

Kang, Zeqi, Kang, Zhe, Jiang, Lang, Deng, Jun, Wu, Zhijun, Li, Liguang, Liang, Heping, Shu, Mingyu

A Method to Evaluate the Compression Ratio in IC Engines with Porous Thermal Barrier Coatings

2018-01-17789/10/2018

The compression ratio is an important engine design parameter. It determines to a large extend engine properties like the achievable efficiency, the heat losses from the combustion chamber and the exhaust losses. The same properties are affected by insulation of the combustion chamber. It is therefore especially important to know the compression ratio when doing experiments with thermal barrier coatings (TBC). In case of porous TBCs, the standard methods to measure the compression ratio can give wrong results. When measuring the compression ratio by volume, using a liquid, it is uncertain if the liquid fills the total porous volume of the coating. And for a thermodynamic compression ratio estimation, a model for the heat losses is needed, which is not available when doing experiments with insulation. The subject of this paper is the evaluation of an alternative method to assess the compression ratio. It is based on motored cylinder pressure data like other thermodynamic methods but does not need a model for the heat losses. The validation and application of the method is done with data from experiments involving two types of porous TBCs, performed on a light duty single cylinder diesel engine. The results indicate that the proposed method accurately predicts the compression ratio for porous thermal barrier coatings.

Somhorst, Joop, Oevermann, Michael, Bovo, Mirko, Denbratt, Ingemar

Power Cylinder Oil Consumption: Transport Mechanisms

J2794_201807 (Current)7/27/2018

This document covers oil transport mechanisms from the power cylinder system which might affect oil consumption. It will not discuss in detail the oil consumption mechanisms from other systems or engine components.

Piston and Ring Standards Committee

Optimization of Oil Separation Unit for Two Stage Turbocharged Engine

2018-28-00667/9/2018

In addition to performance target, recent stringent emission legislation and reduction in oil consumption are the major driving force for engine design and development. In this reference importance of crankcase ventilation has increased immensely and the manufacturers are bound to develop most efficient system with high oil trap efficiency. In crankcase ventilation system, the blow-by gases from the crankcase are routed to the intake manifold through Oil separator system. The oil separator task is to retain the oil part from the blow by gas and send it back to sump. Developing an oil separator for the engine studied here was very challenging considering double stage turbocharger which produces very fine mist of oil and is difficult to separate. The study shows that oil mist coming in blow by is of size 0.3 micron and lesser than it. The major contribution of these fine mists was from turbocharger. Keeping this in view, an oil separation unit which is an integral part of cam cover had been optimized for 1.5 litre, 3 cylinder engine with two stage turbo charging. The separation unit consists of two stage separation, pre & fine separation unit. Pre separation unit trap oil of higher size (Oil droplets) while fine unit separates oil mist from blow by. The optimization had done in stages and finally the oil carry over targets of 2 g/hr & 3 g/hr at 100% & 200% blow by had been achieved with optimized separation unit. 200% blow by was taken for worst condition which replicate the life of engine. The final oil carry values were 1.4 g/hr as against 2 g/hr at 100% blow by while it was 2.3 g/hr as against 3 g/hr at 200% blow by. During trial, it was also ensured that other parameter such as crankcase pressure & air intake depression remains within the target value.

Alam, Md Tauseef, Thakur, Anil, Kumar PS, Venkatesh, Ghadei, Sataya

Overpressurization Release Devices

ARP1322C (Current)6/21/2018

This SAE Aerospace Recommended Practice (ARP) specifies the minimum design and qualification test recommendations for aircraft wheel overpressurization release devices used with tubeless aircraft tires to protect from possible explosive failure of the contained inflation chamber due to overinflation. Devices of this type provide a means, but not the only means, for showing compliance to Subsection 25.731(d) of Part 25 of Title 14 of the Code of Federal Regulations. Devices of this type will not protect against flash fire explosive conditions within the inflation chamber which may occur due to extremely overheated brakes or spontaneous combustion caused by a foreign substance within the inflation chamber. To help protect against this condition, nitrogen (N2) or other inert gas should be used for inflation.

A-5A Wheels, Brakes and Skid Controls Committee

Real-Time Measurement of the Piston Ring Gap Positions and Their Effect on Exhaust Engine Oil Emission

2018-01-50065/5/2018

Measurement techniques for piston ring rotation, engine oil emission and blow by have been implemented on a single-cylinder petrol engine. A novel method of analysis allows continuous and fast real-time identification of the piston ring rotation of the two compression rings, while the mass-spectrometric analysis of the exhaust gas delivers the cylinder oil emission instantly and with a high temporal resolution. Only minor modifications to the piston rings were made for the insertion of the γ-emitters, the rings rotate freely around the circumference of the piston. The idea of this setup is that through online observation at the test bench, instant feedback of the measured variables is available, making it possible to purposefully select and compare measurement points. The high time resolution of the measurement methods enables the analysis of dynamic effects. In this article, the measurement setup and evaluation method is described. Results monitoring the ring gap positions and the exhaust engine oil emission are discussed together with results of blow-by measurements for different speeds and loads. With the production piston assembly, only minor rotational movement of piston rings was apparent at stationary operation. Measurement results of the dynamic effects are discussed.

Uhlig, Benedict Paul, Kirner, Claus, Preuss, Ann-Christin, Wachtmeister, Georg

Machine Learning for Misfire Detection in a Dynamic Skip Fire Engine

2018-01-11584/3/2018

Dynamic skip fire (DSF) has shown significant fuel economy improvements via reduction of pumping losses that generally affect throttled spark-ignition engines. For production readiness, DSF engines must meet regulations for on-board diagnostics (OBD-II), which require detection and monitoring of misfire in all passenger vehicles powered by an internal combustion engine. Numerous misfire detection methods found in the literature, such as those using peak crankshaft angular acceleration, are generally not suitable for DSF engines due to added complexity of skipping cylinders. Specifically, crankshaft acceleration traces may change abruptly as the firing sequence changes. This article presents a novel method for misfire detection in a DSF engine using machine learning and artificial neural networks. Two machine learning approaches are presented. The first method uses a regression-based artificial neural network to calculate expected crank acceleration from various inputs, including fire-skip sequence. The method then compares the output to measured crank acceleration to detect misfire. The second method uses an expanded neural network, which includes the measured crank acceleration as an additional input, to directly predict misfire flags. On-road validation tests of both detection algorithms were carried under steady-state and transient conditions. Results show detection rates above 95% at all tested conditions. Overall, machine learning significantly improved quality and robustness of misfire detection in DSF engines by making use of greater variety of modeling input parameters.

Chen, S Kevin, Mandal, Aditya, Chien, Li-Chun, Ortiz-Soto, Elliott

Experimental Investigation of the Mechanical Behavior of Aluminum Adhesive Joints under Mixed-Mode Loading Conditions

2018-01-0105

4/3/2018

In recent years, structural adhesives have rapidly become the preferred alternative to resistance spot welding in fabricating stronger, lighter aluminum connections. Connections inevitably undergo and must withstand complex quasi-static and/or dynamic loads during their service life. Therefore, understanding how loading conditions affect the mechanical behavior of adhesive joints is vital to their design and the advancement of structural safety. Quasi-static and dynamic tests are performed to analyze both the strength and failure modes of aluminum 6062 substrates bonded by an adhesive (Darbond EP-1506) for an array of loading directions. An Arcan test device, which enables application of mixed-mode loads ranging from pure peel (mode I) to pure shear (mode II) to the adhesive layer, is employed in quasi-static testing. A self-designed medium-speed test machine is utilized to perform dynamic testing. To avoid severe system oscillations exhibited in force measurements during dynamic testing, the Arcan test device is replaced by a set of integrated fixtures to improve stiffness and reduce fixture weight. To induce manifold mechanical responses in the adherend and adhesive materials, the specimens are subjected to a mixture of transverse and shear forces. Experimental results demonstrate that the fracture displacement increases with an increase in testing angle of the applied force, indicating that ductile fracture predominates brittle fracture and governs failure when shear loading is significant in mixed loading scenarios, especially for dynamic tests. Furthermore, dynamic strengthening is observed in samples subjected to peel loading, but is undiscovered in samples tested under mixed loading conditions, where interfacial failure is more likely to occur compared to cohesive failure. This observation reveals that the cohesive zone is reinforced by the strain rate effect, whereas the interface between the adhesive and adherend does not experience this phenomenon.

Li, Victor, Ge, Yulong, Guo, Sai, Su, Zhengliang, Xia, Yong

Divided Exhaust Period Implementation in a Light-Duty Turbocharged Dual-Fuel RCCI Engine for Improved Fuel Economy and Aftertreatment Thermal Management: A Simulation Study

2018-01-02564/3/2018

Although turbocharging can extend the high load limit of low temperature combustion (LTC) strategies such as reactivity controlled compression ignition (RCCI), the low exhaust enthalpy prevalent in these strategies necessitates the use of high exhaust pressures for improving turbocharger efficiency, causing high pumping losses and poor fuel economy. To mitigate these pumping losses, the divided exhaust period (DEP) concept is proposed. In this concept, the exhaust gas is directed to two separate manifolds: the blowdown manifold which is connected to the turbocharger and the scavenging manifold that bypasses the turbocharger. By separately actuating the exhaust valves using variable valve actuation, the exhaust flow is split between two manifolds, thereby reducing the overall engine backpressure and lowering pumping losses. In this paper, results from zero-dimensional and one-dimensional simulations of a multicylinder RCCI light-duty engine equipped with DEP are presented. It is shown that while DEP helped reduce pumping penalty at medium and high loads, the pumping benefit was negated by crankshaft power consumption from a mechanical supercharger which made up for the boost deficit as the low exhaust enthalpy could not be efficiently utilized by a fixed geometry turbocharger (FGT). However, by replacing the FGT with a variable geometry turbocharger (VGT), a 1% improvement in brake-specific fuel consumption (BSFC) over the stock engine configuration was observed at high load, as the VGT allowed more efficient exhaust energy utilization through aspect ratio adjustment. In addition, by closing the blowdown valve at low load, higher exhaust gas temperatures were obtained by bypassing the turbocharger and thereby eliminating exhaust heat losses, which would be useful for aftertreatment thermal management.

Bharath, Anand Nageswaran, Reitz, Rolf, Rutland, Christopher

Insights into Engine Knock: Comparison of Knock Metrics across Ranges of Intake Temperature and Pressure in the CFR Engine

2018-01-0210

4/3/2018

Of late there has been a resurgence in studies investigating parameters that quantify combustion knock in both standardized platforms and modern spark-ignition engines. However, it is still unclear how metrics such as knock (octane) rating, knock onset, and knock intensity are related and how fuels behave according to these metrics across a range of conditions. As part of an ongoing study, the air supply system of a standard Cooperative Fuel Research (CFR) F1/F2 engine was modified to allow mild levels of intake air boosting while staying true to its intended purpose of being the standard device for American Society for Testing and Materials (ASTM)-specified knock rating or octane number tests. For instance, the carburation system and intake air heating manifold are not altered, but the engine was equipped with cylinder pressure transducers to enable both logging of the standard knockmeter readout and state-of-the-art indicated data. For this study, the engine was operated using primary reference fuel 90 (PRF90) at 600 rpm, first following the procedures of the ASTM D2699 research octane number test protocol in order to define the geometric compression ratio set point for standard knock number. Thereafter, compression ratio sweeps were conducted at intake temperatures ranging from 30 to 150°C and intake air boost extending from 0 to 0.3 bar above ambient. The resulting operating map provided a broad envelope of compressed in-cylinder conditions relevant to modern spark-ignition engines. Detailed analysis of the indicated data highlighted a poor correlation between established knock intensity metrics and the knockmeter reading, which is used to characterize a fuel’s octane number. It was further found that the auto-ignition characteristics of PRF90 could be perturbed by means of intake air boosting and heating without being captured by the knockmeter reading.

Rockstroh, Toby, Kolodziej, Christopher P., Jespersen, Mads C., Goldsborough, S. Scott, Wallner, Thomas

Constructing Engine Maps for Full Vehicle Simulation Modeling

2018-01-14124/3/2018

The Environmental Protection Agency (EPA) has collected a variety of engine and vehicle test data to assess the effectiveness of new automotive technologies in meeting greenhouse gas (GHG) and criteria emission standards and to monitor their behavior in real world operation. EPA’s Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) tool was created to estimate GHG emissions from vehicles using various combinations of advanced technologies and has been refined using data from testing conducted at EPA’s National Vehicle and Fuel Emissions Laboratory. This paper describes a process for constructing complete engine maps using engine dynamometer and in-vehicle test data for use in ALPHA or any other full vehicle simulation which performs similar analyses. The paper reviews how to use available steady state and transient test data to characterize different operating conditions, and then combine the data to construct a complete engine map suitable for ALPHA model simulation. The paper also discusses the use of default values when specific engine test data are unavailable. Finally, tools used to assess the quality of the generated complete engine maps are presented.

Dekraker, Paul, Barba, Daniel, Moskalik, Andrew, Butters, Karla

A Model for Crank-Angle-Resolved Engine Cylinder Pressure Estimation

2018-01-11574/3/2018

Real-time measurement or estimation of crank-angle-resolved engine cylinder pressure may become commonplace in the next generation of engine controllers to optimize spark, valve timing, or compression ratio. Toward the development of a real-time cylinder pressure estimator, this work presents a crank-angle-resolved engine cylinder pressure estimation model that could accept inputs such as speed, manifold pressure and throttle position, and deliver crank-angle resolved cylinder pressure in real-time, at engine speeds covering the useful operating range of most engines. The model was validated by comparing simulated cylinder pressure with thirteen sets of cylinder pressure data, from two different commercial engines from two different OEMs. Estimated pressures were compared against the actual measured pressure traces. The average relative error is about 3% while the maximum relative error is 5%. Both can be improved with further tuning. The long-term goal is to design an optimal hardware component for cylinder pressure estimation to be included in an embedded system for hardware-in-the-loop simulation or the next generation engine controllers. Toward that goal, the current model, which includes only the closed valve period at this time, was implemented in hardware. Tests show that the hardware-based model is capable of estimating crank-angle-resolved cylinder pressure at engine speeds up to 9000 rpm.

Wu, Jing, Jacoby, Andres, Llamocca, Daniel, Sangeorzan, Brian

Cylinder Pressure Based Cylinder Charge Estimation in Diesel Engines with Dual Independent Variable Valve Timing

2018-01-08624/3/2018

With stricter emission legislations and demands on low fuel consumption, new engine technologies are continuously investigated. At the same time the accuracy in the over all engine control and diagnosis and hence also the required estimation accuracy is tightened. Central for the internal combustion control is the trapped cylinder charge and composition Traditionally cylinder charge is estimated using mean intake manifold pressure and engine speed in a two dimensional lookup table. With the introduction of variable valve timing, two additional degrees of freedom are introduced that makes this approach very time consuming and therefore expensive. Especially if the cam phasers are given large enough authority to offer powerful thermal management possibilities. The paper presents a physical model for estimating in-cylinder trapped mass and residual gas fraction utilizing cylinder pressure measurements, and intake and exhaust valve lift profiles. The cylinder pressure at intake and exhaust valve opening and closing together with manifold pressures and temperatures are combined with thermodynamic and heat transfer models to calculate the trapped cylinder mass. The estimator is validated on test data from a prototype engine with dual independent cam phasers under a wide range of operating conditions, including large variations in valve timing ranging from scavenging to early exhaust cam timing for thermal management. The main contribution is the developed model, with the ability to accurately estimate the trapped cylinder charge during large independent variations in both intake and exhaust valve timing.

Thomasson, Andreas, Nikkar, Sepideh, Höckerdal, Erik

Simulation Study of 1D-3D Coupling for Different Exhaust Manifold Geometry on a Turbocharged Gasoline Engine

2018-01-01824/3/2018

One-dimensional (1D) simulation tools, the computing speed of which is relatively fast, usually solve simple complexity problems. The solving process of 1D simulation is mostly based on one-dimensional dynamic equations and empirical laws and thus in some cases it cannot obtain a similar accuracy with the time-consuming three-dimensional (3D) simulation tools. The 1D-3D co-simulation, which combines the advantages of the two simulation tools while minimizes the disadvantages, is a method that integrates and runs the two simulation tools concurrently. The coupled simulation can offer a 3D analysis for which a detailed information is needed while offer system level information in the rest of the whole system where averaged results are sufficient. The approach not only minimizes the computational cost, but avoids demand for imposing accurate boundary conditions to the 3D simulation. But nowadays, a lot of paper only use the approach to obtain boundary condition from 1D environment, few study focus on the influence of 3D part on system. (e.g influence of intake or exhaust manifold on flow in cylinder in co-simulation).The objective of this study includes two aspects, one compares the difference between 1D and the 1D/3D coupling, the other studies the influence of the 4-1 and 4-2-1 exhaust manifold on in-cylinder residual fraction gas (RGF) based on the proposed 1D and 3D co-simulation approach. It describes a detailed analysis of the integrated 1D-3D simulation for two different exhaust manifold geometries on a turbocharged gasoline engine. The research results show that the induction process of the original 1D model and the co-simulation model were nearly equal, but the exhaust pressure of the coupled model was smoother than that of the original 1D model. The 4-1 exhaust manifold has a larger residual gas fraction due to the more severe pulse interference and the 4-2-1 exhaust manifold is able to mitigate this phenomenon by separating the runner 1/runner 4 with runner 2/runner 3. Furthermore, by added a spacer plate at exit port of 4-2-1 manifold, it can further reduce in-cylinder RGF and enable more uniformity among four cylinders. Therefore, the 4-2-1 exhaust manifold can be used to enhance the engine performance to achieve the concept of downsizing and down-speeding, and also it can be adopted to optimize the fuel efficiency by advancing the spark timing.

Zhang, Chaolin, Hu, Bo, lai, Chenguang, Zhang, Hailin, Qin, Ling, Leng, Xiaoli, Huang, Wenpeng

Simulation and Experimental Research on Compression Release Engine Brake Performance

2018-01-13824/3/2018

A 3D grid model of engine brake is established for an automobile engine. The dynamic compression release braking process is simulated by using this model. In the process of engine braking, the movement of valve and piston causes changes of the internal flow field of the engine. In this paper, the movement of valve and piston were defined by using the dynamic grid technology, so that the numerical simulation is closer to the actual situation via the updating of grid. Based on the relevant parameters of compression release engine brake (including the opening of the exhaust valve, the engine speed and the exhaust back pressure), the pressure and power of the compression release braking system were simulated under the conditions of multiple operating conditions and experimental verification was carried out. The results showed that the braking works of the compression release engine brake are mainly from the compression stroke and the exhaust stroke. At a certain speed, each compression release valve opening corresponds to an optimal compression release valve advance angle in order to ensure the optimal engine brake performance. Besides, the larger the compression release valve opening, the smaller the corresponding optimal valve advance angle. Using of decompression brake can achieve better braking effect.

Jia, Guohai, Zhang, Daming, Gong, Jinke, Li, Lijun, Wang, Yunke

Turbocharger Impact on Diesel Electric Powertrain Performance

2018-01-09654/3/2018

When electrifying the powertrain, there arises an opportunity to revise the traditional turbocharging trade-off between fuel-economy and transient performance. With the help of electrification, it might be possible to make the trade-off in favor of fuel economy, since transient response can be improved by the electric machine. The paper investigates this trade-off by looking at three turbocharger selections. A conventionally dimensioned turbocharger, an efficiency optimized turbocharger with maintained flow capacity, and an efficiency optimized turbocharger with increased flow capacity. The concepts are evaluated on the following cases: stationary operation, engine tip-in performance, vehicle acceleration performance, and on road fuel economy performance. The investigation is based on a validated mean value engine model of a six cylinder inline CI engine, and on a validated driveline and vehicle model of a heavy-duty truck. The evaluations are made with the help of simulations and numerical optimal control. The results show that there is a fuel saving potential, and that the transient response is improved by the electric machine.

Leek, Alf Erik Viktor, Eriksson, Lars

Pressure Amplitude Influence on Pulsating Exhaust Flow Energy Utilization

2018-01-09724/3/2018

A turbocharged Diesel engine for heavy-duty on-road vehicle applications employs a compact exhaust manifold to satisfy transient torque and packaging requirements. The small exhaust manifold volume increases the unsteadiness of the flow to the turbine. The turbine therefore operates over a wider flow range, which is not optimal as radial turbines have narrow peak efficiency zone. This lower efficiency is compensated to some extent by the higher energy content of the unsteady exhaust flow compared to steady flow conditions. This paper experimentally investigates the relationship between exhaust energy utilization and available energy at the turbine inlet at different degrees of unsteady flow. A special exhaust manifold has been constructed which enables the internal volume of the manifold to be increased. The larger volume reduces the exhaust pulse amplitude and brings the operating condition for the turbine closer to steady-flow. The operating points are defined by engine speed and boost pressure. From these values the isentropic turbine work is calculated and with the measured compressor work the mean turbine efficiency is estimated. The results show that more energy has to be provided to the turbine at larger exhaust manifold volumes to maintain a constant boost pressure, indicating that the efficiency of the turbine decreases.

Holmberg, Ted, Cronhjort, Andreas, Stenlaas, Ola

Exploring Engine Oil Reactivity Effects on End Gas Knock in a Direct-Injection Spark Ignition Engine

04-11-01-0002

3/7/2018

An experimental study was conducted in a direct-injection (DI) spark-ignited engine to determine the extent to which oil reactivity impacts combustion phasing and knock propensity. Three engine oils were examined: a baseline 20W30 oil from conventional base stock, a 5W30 oil from a synthetic base stock, and a jet oil from a hindered ester base stock. The engine was operated at a constant fueling rate of 24.7 mg/injection for two engine speed conditions (1500 and 2000 rpm) using two cam profile conditions (high and low lift), for a total of four operating conditions. Spark timing sweeps were conducted at each of the four operating conditions. Results were analyzed for an engine oil impact on combustion phasing, cycle-to-cycle variability, combustion duration, knock propensity, and knock intensity. No correlation between engine oil type and any of these performance metrics could be identified. Measurements showed that the oil consumption rate for this engine is low and comparable to engines compliant with U.S. Tier 1 and Tier 2 emissions standards, consuming 1.4 g/kg of fuel consumed (150 g for 20 hours of operation). The lack of a correlation between the oil type and engine performance can be attributed to this low level of oil consumption, resulting in very little interaction between the oil and the combustion chamber contents.

Szybist, Jim, West, Brian

Design of a New Intake Manifold of a Single Cylinder Engine with Three Stages

2017-36-017211/7/2017

The intake system of an internal combustion engine plays a key role to determine its performance. Gas dynamics varies with many factors, such as whether it is fuel injected or carbureted engine, temperature, runner length and diameter, valve timing, number of cylinders and others factors. A careful design of the intake system provides the engineer a possibility to manipulate the dynamics of the gas, allowing taking advantage of the engine's operation at some moments. The aim of the current paper is investigates the effects of intake runner length and diameter on the performance of a four stroke and single cylinder engine, design a three stages intake manifold for this engine and elaborate a design algorithm to find the best intake runner length and diameter configuration. The characteristics that were taken in consideration to evaluate the engine performance were the brake power, volumetric efficiency and trapped gas. The performance evaluation was made with the assistance of a 1D-simulation software called GT-Power and an optimization software, modeFrontier, where it was used to improve the efficiency to choose the best configuration of the intake runner length and diameter of each engine speed. The study showed that in some moments it is possible to achieve a high volumetric efficiency thanks to the tuning effect, which demonstrate that if adjusting the intake runner length and diameter, making the pressure waves arrives exactly at the time when the inlet valve opens, it allows to reach an extra boosting on the admission time.

Alves, Luiz Otávio F. T., dos Santos, Marcos Gabriel Diodato, Urquiza, Alexandre Barreto, Guerrero, Jorge Henriquez, de Lira, José Claudino, Abramchuk, Vagner

Modeling of Unsteady Heat Transfer Phenomena at the Intake Manifold of a Diesel Engine and Its Application to 1-D Engine Simulation

2017-32-009711/5/2017

In the past two decades, internal combustion engines have been required to improve their thermal efficiency in order to limit hazardous gas emissions. For further improvement of the thermal efficiency, it is required to predict the mass of intake air into cylinders in order to control the auto-ignition timing for CI engines. For an accurate prediction of intake air mass, it is necessary to model the heat transfer phenomena at the intake manifold. From this intention, an empirical equation was developed based on Colburn equation. Two new arguments were presented in the derived formula. The first argument was the addition of Graetz number, where it characterized the entrance region thermal boundary layer development and its effect on the heat transfer inside the intake manifold. As the second argument, Strouhal number was included in order to represent intake valve effect on heat transfer. This study compared experimental data with the present empirical equation, and average error was estimated to be 3.1%, which was significantly improved in comparison with the Colburn equation. Furthermore, derived empirical heat transfer equation was implemented to the intake manifold model of a diesel engine in 1-D engine simulation. The study confirmed the influence of the heat transfer phenomena, and its importance to intake air. At IVC, temperature difference between Colburn equation and derived equation was calculated to be 3.8 K. This corresponded to an advanced auto-ignition timing by 0.78 deg. CA, which gives an estimated improvement of 0.22% when evaluating both the thermal efficiency and CO2 emission.

Yilmaz, Emir, Joji, Hayao, Ichiyanagi, Mitsuhisa, Suzuki, Takashi

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