Browse Topic: Intake systems

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Acoustic Assessment in a Small Displacement Diesel Engine2014-32-01291/30/2026
In the last years, the increasing concern for the environmental issues of IC engines has promoted the development of new strategies capable of reducing both pollutant emissions in atmosphere and noise radiation. Engines can produce different types of noise: 1) aerodynamic noise due to intake and exhaust systems and 2) surface radiated noise. Identification and analysis of noise sources are essential to evaluate the individual contribution (injection, combustion, piston slap, turbocharger, oil pump, valves) to the overall noise with the aim of selecting appropriate control strategies. Previous paper focused on the combustion related noise emission. The research activity aimed at diagnosing and controlling the combustion process via acoustic measurements. The optimal placement of the microphone was selected, where the signal was strongly correlated to the in-cylinder pressure development during the combustion process. Analysis and processing of the sound emission allowed the acoustic contribution of the combustion event to be isolated. Some indices capable of relating the combustion noise radiation back to the combustion development were defined. This paper presents an experimental activity devoted to analyze the entire noise generation process of a small displacement diesel engine. The purpose was to identify the contribution of the different sources (mechanical, combustion, fluid dynamic) to the overall emission. The methodology here proposed analyze the specific signature in the frequency domain of each source. The final objective was to use the microphone signal acquired in a proper selected location, to obtain indications about the effective strategies to achieve noise reduction. The repetitiveness of the measurements was guaranteed by a network encircling the engine. Microphones were placed in different positions and tests were performed in the complete engine operative field. In the paper, the experimental set-up is described, the methodology is presented. Results are then shown and discussed.
Chiatti, Giancarlo, Recco, Erasmo, Chiavola, Ornella, Conforto, Silvia
Guidelines for Engine Component TestsARP5757B (Current)11/26/2025
This SAE Aerospace Recommended Practice (ARP) provides guidance for substantiating the airworthiness of aircraft engine components. Generally these components are associated with the engine control system, the system or systems that allow the engine to provide thrust or power as demanded by the pilot of the aircraft while also ensuring the engine operates within acceptable operating limits. But these components may also include hardware and systems associated with engine lubrication, engine or aircraft hydraulic or electrical systems, aircraft environmental control systems, thrust reverser control, or similar aircraft or engine propulsion system functions. This paper develops the concept of using a 26 item matrix of environmental conditions for evaluating aircraft engine component airworthiness. This approach is compatible with current practices used in the industry and has been accepted by engine certification authorities as part of engine certification programs.
E-36 Electronic Engine Controls Committee
Guidelines for the Integration of Electronic Engine Control Systems for Transport Category (Part 25) and General Aviation (Part 23) AircraftAIR5924B (Current)11/26/2025
This SAE Aerospace Information Report (AIR) provides methodologies and approaches that have been used to install and integrate full-authority-digital-engine-control (FADEC) systems on transport category aircraft. Although most of the information provided is based on turbofan engines installed on large commercial transports, many of the issues raised are equally applicable to corporate, general aviation, regional and commuter aircraft, and to military installations, particularly when commercial aircraft are employed by military users. The word “engine” is used to designate the aircraft propulsion system. The engine station designations used in this report are shown in Figure 1. Most of the material concerns an Electronic Engine Control (EEC) with its associated software, and its functional integration with the aircraft. However, the report also addresses the physical environment associated with the EEC and its associated wiring and sensors. Since most of today’s transport category engines use dual-channel full-authority digital engine control (FADEC) systems, this is the configuration which is addressed. A typical FADEC system configuration is shown in Figure 2.
E-36 Electronic Engine Controls Committee
TightAIR12122024A (Current)12/12/2024
New Scoop
A-6 Aerospace Actuation, Control and Fluid Power Systems
TightAIR12122024 (Historical)12/12/2024
Scoop
A-6 Aerospace Actuation, Control and Fluid Power Systems
Marine Carburetors and Fuel Injection Throttle BodiesJ1223_202012 (Current)12/9/2020
This SAE Recommended Practice covers all carburetors and throttle bodies used on permanently installed gasoline marine engines.
Marine Engine Fuel Systems Committee
Performance Deterioration of Rotorcraft Engines fitted with Particle SeparatorsF-0076-2020-1633510/5/2020
Military rotorcraft engines operating in harsh environments routinely ingest large quantities of mineral dust, which can degrade components and ultimately reduce operability. Time off-wing for unscheduled maintenance is a costly burden, both financially and operationally. Rapidly predicting engine deterioration rates as a function of the mission presents an opportunity to optimise flow of supplies, better manage fleets, and perform safety risk assessments when dust loading is expected to be particularly high. In the current contribution, we present our ongoing efforts in this field with a new methodology for assessing the effectiveness of inertial particle separators and quantifying the changes they impart to the inbound dust. We demonstrate that both the concentration reduction and the modification to the particle size distribution can be made on the basis of a single independent variable- a generalised Stokes number for inertial particle separators- and a single performance parameter- the corrected separation efficiency. To develop these parameters we conduct numerical simulations of the flow through a generic axi-symmetric inertial particle separator, over a range of five mass flow rates, three scavenge mass flow rates, and 16 particle diameters. In addition to this, a framework is presented to enable an estimation of the dust concentration at the engine intake. This is achieved by correlating the total wake strength to an existing dust landing trial dataset. A coupled rotorcraft-engine model is then used to combined the two methodologies to investigate the influence of engine mass flow rate on dust ingestion rate. A weak non-linear relationship is observed, which arises due to the simultaneous increase in wake strength with engine mass flow rate as rotor power requirements increase. The additional dust stirred up by the stronger wake leads causes this non-linearity. Finally, we show that an improvement in separation efficiency caused by higher engine mass flow rate is far outweighed by the associated increase in dust loading in this condition.
Bojdo, Nicholas, Appleton, Wesley, Ellis, Matthew, Filippone, Antonio, Hee, Jee-Loong
Infrared/Visible Optical Diagnostics of RCCI Combustion with Dieseline in a Compression Ignition Engine2020-01-05574/14/2020
Compression ignition engines are widely used for transport and energy generation due to their high efficiency and low fuel consumption. To minimize the environmental impact of this technology, the pollutant emissions levels at the exhaust are strictly regulated. To reduce the after-treatment needs, alternative strategies as the low temperature combustion (LTC) concepts are being investigated recently. The reactivity controlled compression ignition (RCCI) uses two fuels (direct- and port- injected) with different reactivity to control the in-cylinder mixture reactivity by adjusting the proportion of both fuels. In spite of the proportion of the port-injected fuel is typically higher than the direct-injected one, the characteristics of the latter play a main role on the combustion process. Use of gasoline for direct injection is attractive to retard the start of combustion and to improve the air-fuel mixing process. In this work, the influence of the direct-injected fuel properties on RCCI combustion mode is studied in an optical compression ignition engine. Gasoline fuel is injected in the intake manifold while a blend of gasoline and diesel (a.k.a. dieseline) is directly injected into the cylinder. Non-conventional optical diagnostics in the visible and infrared spectra are applied for the direct investigation of the in-cylinder phenomena during the injection and the combustion processes. A low-luminosity, mainly kinetically controlled combustion mode has been observed.
Sequino, Luigi, Mancaruso, Ezio, Monsalve-Serrano, Javier, Garcia, Antonio
Optical Characterization of the Combustion Process inside a Large-Bore Dual-Fuel Two-Stroke Marine Engine by Using Multiple High-Speed Cameras2020-01-07884/14/2020
Dual-fuel engines for marine propulsion are gaining in importance due to operational and environmental benefits. Here the combustion in a dual-fuel marine engine operating on diesel and natural gas, is studied using a multiple high-speed camera arrangement. By recording the natural flame emission from three different directions the flame position inside the engine cylinder can be spatially mapped and tracked in time. Through space carving a rough estimate of the three-dimensional (3D) flame contour can be obtained. From this contour, properties like flame length and height, as well as ignition locations can be extracted. The multi-camera imaging is applied to a dual-fuel marine two-stroke engine, with a bore diameter of 0.5 m and a stroke of 2.2 m. Both liquid and gaseous fuels are directly injected at high pressure, using separate injection systems. Optical access is obtained using borescope inserts, resulting in a minimum disturbance to the cylinder geometry. In this type of engine, with fuel injection from positions at the rim of the cylinder, the flame morphology becomes asymmetric. The optical spatial mapping and tracking method is demonstrated to be well suited for the study of such an asymmetric combustion system. Spatial mapping and tracking of flame position is applied to both engine operating modes; normal diesel operation and dual-fuel operation with diesel pilot ignition of the gas. Similarities and differences between diesel and gas flame shape and development can thus be visualised directly. The effects of changing charge density, gas injection pressure and injection nozzle geometry on the flame geometry and development are also studied.
Hult, Johan, Matamis, Alexios, Baudoin, Eric, Mayer, Stefan, Richter, Mattias
The Prospect and Benefits of Using the Partial-Averaged Navier-Stokes Method for Engine Flows2020-01-11074/14/2020
This paper presents calculations of engine flows by using the Partially-Averaged Navier Stokes (PANS) method (Girimaji [1]; [2]). The PANS is a scale-resolving turbulence computational approach designed to resolve large scale fluctuations and model the remainder with appropriate closures. Depending upon the prescribed cut-off length (filter width) the method adjusts seamlessly from the Reynolds-Averaged Navier-Stokes (RANS) to the Direct Numerical Solution (DNS) of the Navier-Stokes equations. The PANS method was successfully used for many applications but mainly on static geometries, e.g. Basara et al. [3]; [4]. This is due to the calculation of the cut-off control parameter which requires that the resolved kinetic energy is known and this is usually obtained by suitably averaging of the resolved field. Such averaging process is expensive and impractical for engines as it would require averaging per cycles. A recently published work on PANS (Basara et al. [5]) opens a prospect of more cost-effective engine calculations. This new PANS approach solves the additional equation for a total resolved turbulent kinetic energy which enables continuous (in situ) update of the resolution parameter fk. Thus fk. is dynamically specified in time and space depending on the flow and computational meshes. Calculation results of the IC engine will be compared with the measurements which include cycle-to-cycle variations and emission data.
Basara, Branislav, Pavlovic, Zoran, Girimaji, Sharath
CO2 Neutral Heavy-Duty Engine Concept with RCCI Combustion Using Seaweed-based Fuels2020-01-08084/14/2020
This paper focusses on the application of bioalcohols (ethanol and butanol) derived from seaweed in Heavy-Duty (HD) Compression Ignition (CI) combustion engines. Seaweed-based fuels do not claim land and are not in competition with the food chain. Currently, the application of high octane bioalcohols is limited to Spark Ignition (SI) engines. The Reactivity Controlled Compression Ignition (RCCI) combustion concept allows the use of these low carbon fuels in CI engines which have higher efficiencies associated with them than SI engines. This contributes to the reduction of tailpipe CO2 emissions as required by (future) legislation and reducing fuel consumption, i.e. Total-Cost-of-Ownership (TCO). Furthermore, it opens the HD transport market for these low carbon bioalcohol fuels from a novel sustainable biomass source. In this paper, both the production of seaweed-based fuels and the application of these fuels in CI engines is discussed. Ethanol and butanol are considered as the most viable fuels derived from seaweed. The potential of these fuels has been evaluated for the dual-fuel RCCI mode regarding efficiency and NOx emissions. The operating conditions that have been varied are mainly the fuel blend ratio (BR), fuel injection timing, and EGR rate on both a HD single-cylinder and on a HD multi-cylinder engine. The results for E85/diesel-RCCI demonstrate that CI engine-like efficiencies are feasible. The gross Indicated Thermal Efficiency (ITE) reaches up to 52% and 46.5% using E85 in a single-cylinder and a multi-cylinder engine, respectively. The first results using biomass based butanol show greater difficulty in realizing targeted efficiencies on the multi-cylinder engine due to the higher fuel reactivity and higher boiling temperature than ethanol. The gross ITE reaches up to 51.6% and 38.5% using butanol in a single-cylinder and a multi-cylinder engine, respectively. The demonstrated potential of seaweed-based fuels is an important driver for upscaling the production process of these fuels. Furthermore, future development activities will focus on improving the brake thermal efficiency of the RCCI engine running on seaweed-based fuels. Improving the low reactivity fuel-air mixture preparation will be key to achieve this.
Seykens, Xander, Bekdemir, Cemil, Han, Jinlin, Willems, Robbert, Van Hal, Jaap
Analysis of In-Cylinder Flow and Cycle-to-Cycle Flow Variations in a Small Spark-Ignition Engine at Different Throttle Openings2020-01-07934/14/2020
Flow variations from one cycle to the next significantly influence the mixture formation and combustion processes in engines. Therefore, it is important to understand the fluid motion and its cycle-to-cycle variations (CCVs) inside the engine cylinder. Researchers have generally investigated the cycle-to-cycle flow variations in moderate- to large-sized engines. In the present work, we have performed the flow measurement and analysis in a small spark-ignition engine. Experiments are conducted in an optically accessible, single-cylinder, port-fuel-injection engine with displacement volume of 110 cm3 at different throttle openings (i.e. 50% and WOT) using particle image velocimetry. Images are captured at different crank angle positions during both intake and compression strokes over a tumble measurement plane, bisecting the intake and exhaust valves and passing through the cylinder axis. The histograms of vorticity are used as a metric for the quantification of cycle-to-cycle flow variations. It is found that for wide-open (i.e. 100%) throttle, cycle-to-cycle variations first increased from 76 CAD (after TDC of intake) to a maximum value at about 118 CAD, and then decreased during the late intake and early compression to a minimum at about 232 CAD for measured crank angle degrees. Results also showed that cycle-to-cycle variations for 50% and wide-open throttle conditions were comparable for all measured CADs. This similarity between 50% and WOT conditions based on histograms of vorticity was found to be consistent with turbulent kinetic energy (TKE) results. In addition, CFD simulations are also performed using CONVERGE software, and a great resemblance is observed between CFD simulations and experimental results for both 50% and WOT conditions.
Alam, Afaque, Mittal, Mayank, Lakshminarasimhan, V
The Isochoric Engine2020-01-07964/14/2020
For the gasoline engine, the isochoric process is the ideal limit of the ideal processes. During the project, a combustion engine with real isochoric boundary conditions is built. A “resting time” of the piston for several degrees crank angle in the top dead center (TDC) can be realized with a special crank drive. This crank drive consists of two crankshafts with different strokes, which are combined. The two crankshafts rotate with a ratio of two to one in opposite directions. The total stroke corresponds to the amount of the first crankshaft, so it is possible to investigate different strokes of the second crankshaft in the same crankcase. Different “resting times” can be achieved by different strokes of the second crankshaft. A specific combination of both crankshafts make a stroke possible which corresponds to that of a conventional combustion engine. In addition to the standard cylinder pressure sensor, a quick surface temperature probe is also used as supplementary measurement technology. The influence of isochoric combustion is studied with constant air mass and constant lambda at three different strokes of the small crankshaft.
Burger, Benjamin, Bargende, Michael
Combustion System Development in GAC Turbocharged Miller GDI Engine with 0.5L/Cylinder2020-01-08384/14/2020
GAC Group has set up two modular engine families, G and GS, for various vehicle classes equipping demands. G family engines, which have already gone through three generations, target for the higher torque and power, the lower fuel consumption and the future strict emission standards. For the latest generation, new technologies were added to achieve the development goals based on the previous modular engines. For example, miller combustion cycle with increased compression ratio is introduced in the newer engine combustion system. Additional key technologies such as 350 bar injection system and high tumble intake ports are also applied. The combustion system development, which established on the GAC Combustion Controlling System (GCCS), was facilitated by integrated use of advanced optical measurements and computational fluid dynamics for improving the in-cylinder flow, fuel sprays and the interaction between them. This paper presents the analytical work done to develop the combustion systems. A higher tumble intake port design enhances the motion in intake process, the well-organized in-cylinder flow may bend over the sprays and keep them from interacting with the cylinder. The redesigned spray structure and piston bowl could do good for a reasonable mixture formation, which decreases the soot and HC emissions, especially for the cold-start conditions. Results from engine test bench experiments show that all of the new generation of the 0.5L/cylinder turbocharged DI gasoline engines can meet the strict legislation for nearest or some considerable time to come.
Li, Yuhuai, Chen, Hong, Du, Jiakun, Wu, Jian, Zhan, Wenfeng, Wu, Guangquan, Lin, Sicong, Shao, Fake
Investigation of the Impacts of Spark Plug Orientation on Combustion Stability under Lean SI Operation2020-01-11214/14/2020
The increasingly stringent restrictions on vehicle emissions and fuel consumption are driving the development of gasoline engines towards lean combustion. Increasing ignition energy has been considered an effective way to achieve lean operation conditions. To further improve the lean limit of engine combustion, the influence of the spark plug orientation on the combustion stability under lean operation should be explored. In this investigation, the original machine spark plug orientation, 90 degrees clockwise rotation, and 180 degrees clockwise rotation are studied to analyze the impact of spark plug orientation. The combustion experiment was carried out under the condition of low excess air ratio of the original machine and high excess air ratio with a 450 mA high energy ignition. It is found that changing the orientation of the spark plug had little effect on combustion at low excess air ratio; however, under high excess air ratio (ultra-lean operation), spark plug orientation had a great influence on combustion stability. The combustion stability can be significantly improved when the spark plug orientation is vertical to the intake direction. What’s more, we found that when the engine speed was low as 1000rpm, the effects of the spark plug orientation were not very clear. However, when the engine speed increased to 2000rpm, the lean operation limit can be improved from an excess air ratio of 1.78 to 1.96 by adjusting the orientation of the spark plug.
Gu, Qifan, Xu, Min, Ye, Chang, Hung, David, Li, Xuesong
A Novel Design of Engine Misfire Detection System Suitable for Small Capacity S.I. Engine for Two Wheeled Vehicle2020-01-02674/14/2020
As per the OBD II regulations, it is essential to detect and monitor the misfire event in an I.C. engine. Misfiring of an I.C. engine affects the quality of combustion and degrades the performance of catalyst convertor which can lead to an increase of emissions. Misfire event can be categorized as partial or complete, based on amount of combustion occurred during that particular engine cycle. Most of the production engine for non-two wheeler vehicle identifies misfire by monitoring angular acceleration of the engine crank-shaft. However, single cylinder engine with lower capacity (less than 300 cubic centimeter) provides challenges to identify misfire due to low mechanical inertia of the I.C. engine using the same approach. The problem of misfire identification for this category of I.C. engine turn out to be more challenging due to presence of various load disturbances on the powertrain. Ion current sensing is one of the alternate method to detect misfire, which received good attention during the last decade of the previous century. When the air-fuel mixture ignites inside the I.C. engine cylinder, air particles get ionize. By applying a suitable high-voltage on spark plug, it is possible to measure the ion current as the amount of ion current reflects the level of ionization of air fuel mixture. The ion current measurement system presented in this paper is implemented in a production vehicle ignition system for two wheeled vehicles. The vehicle ignition system is unique due to the shorted terminals of high & low voltage sides. Due to the shorted primary and secondary connection, it is challenging to implement ion current measurement system using available research work. The proposed novel design of ion current measurement system accommodates the above constraint. The ion current signal is captured during normal combustion event as well as by creating misfire in the combustion. There are significant changes observed in the ion current signal with and without misfire. The information extracted from the ion current signal is utilized to detect the misfire. The proposed design is analyzed with suitable 1D theoretical model of the ignition system.
Bagade, Monika Jayprakash, Das, Himadri Bhushan, Raveendranath Sr, Arjun, Jabez Dhinagar, S
Influence of Port Water Injection on the Combustion Characteristics and Exhaust Emissions in a Spark-Ignition Direct-Injection Engine2020-01-02944/14/2020
It is well known that engine downsizing is still the main energy-saving technology for spark-ignition direct-injection (SIDI) engine. However, with the continuous increase of the boosting ratio, the gasoline engine is often accompanied by the occurrence of knocking, which has the drawback to run the engine at retarded combustion phasing. Besides, in order to protect the turbine blades from being sintered by high exhaust temperature, the strategies of fuel enrichment are often taken to reduce the combustion temperature, which ultimately leads to a high level of particulate number emission. Therefore, to address the issues discussed above, the port water injection (PWI) techniques on a 1.2-L turbocharged, three-cylinder, SIDI engine were investigated. Measurements indicate that the optimization of spark timing has a significant impact on its performance. The two factors of the water substance itself and spark advance caused by the knock mitigation are trade-offs, which eventually affect the combustion performance. Under knock limited spark advance (KLSA) condition, we find that the application of port water injection could effectively advance the combustion phasing and reduce exhaust gas temperature, which makes it possible to eliminate fuel enrichment and further enhances the fuel economy improvement at the maximum power point. As a result, about 5.2%-18.4% improvements in the fuel economy are obtained under different engine operating conditions. For the exhaust emissions, due to the increasing heat capacity of the mixture and the elimination of fuel enrichment, port water injection techniques cause an 85.3% reduction in particle number concentration. However, it shows that for a given λ, an increase in the water/fuel ratio would cause higher THC emissions, which is contributed to the occurrence of more quenching caused by higher peak combustion pressure. Finally, the potential of PWI on the engine combustion characteristics and emissions performance was revealed.
Fan, Yadong, Wu, Tianbao, Li, Xuesong, Xu, Min, Hung, David
Numerical Investigation of the Effects of Port Water Injection Timing on Performance and Emissions in a Gasoline Direct Injection Engine2020-01-02874/14/2020
Port water injection is considered as a promising strategy to further improve the combustion performance of internal combustion engines for its benefit in knock resistance by reducing the cylinder temperature. A thorough investigation of the port water injection technique is required to fully understand its effects on the engine combustion process. This study explores the potential of the port water injection technique in improving the performance of a turbo charged Gasoline Direct Injection engine. A 3D computational fluid dynamics model is applied to simulate the in-cylinder mixing and combustion for this engine both with and without water injection. Different water injection timings are investigated and it is found that the injection timing greatly effects the mass of water which enters the combustion chamber, both in liquid and vapor form. Comparison have been given between the original engine and the water injection one and the results show that the water injection can reduce the cylinder temperature both in the compressing and combustion strokes. The pressure oscillation is also suppressed which indicates a better knocking resistance for water injection strategy. An optimized injection timings could be found for a particular load condition and also lead to a better combustion performance and emissions.
Yin, Peng, Li, Xuesong, Hung, David, Fan, Yadong, Xu, Min
Effect of Different Geometrical Changes in the Intake Manifold of a DI Diesel Engine Fueled with Biodiesel-Diesel Blends2020-01-03464/14/2020
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
Starting Process Control of a 2-Cylinder PFI Gasoline Engine for Range Extender2020-01-03154/14/2020
With the increasing worldwide concern on environmental pollution, battery electrical vehicles (BEV) have attracted a lot attention. However, it still couldn’t satisfy the market requirements because of the low battery power density, high cost and long charging time. The range-extended electrical vehicle (REEV) got more attention because it could avoid the mileage anxiety of the BEVs with lower cost and potentially higher efficiency. When internal combustion engine (ICE) works as the power source of range extender (RE) for REEV, its NVH, emissions in starting process need to be optimized. In this paper, a 2-cylinder PFI gasoline engine and a permanent magnet synchronous motor (PMSM) are coaxially connected. Meanwhile, batteries and load systems were equipped. The RE co-control system was developed based on Compact RIO (Compact Reconfigurable IO), Labview and motor control unit (MCU). Focused on the starting process, the effects of first firing speeds, throttle control strategies and coolant temperatures were tested. The results show that the higher first firing speed is preferred without obvious torque fluctuation, and longer throttle switching duration to high load results in lower HC emissions. But the compromised duration for the engine in this paper is 5s.
Li, Minglong, Zhang, Ran, Zeng, Xingyu, Ding, Weiqi, Mao, Weiang, Jin, Shaoye, Xu, Rufeng, Yuan, Dengke, Hu, Zongjie, Zhong, Zaimin, Li, Liguang
Devices Providing Backfire Flame Control for Gasoline Engines in Marine ApplicationsJ1928_202002 (Historical)2/25/2020
This SAE Standard covers the minimum requirements for design, construction, and testing of devices to prevent the propagation of backfire flame from within the gasoline engine to the surrounding atmosphere.
Marine Technical Steering Committee
Engine Order Sound Simulation by Active Sound Generation for Electric Vehicles10-04-02-00112/4/2020
In this article, an active sound generation (ASG) system is proposed to simulate engine order sound that is typically found in vehicles equipped with internal combustion engines. Based on an A-class electric SUV, a mathematical model simulating engine order sound is established, and a short-time Fourier transform and synthesis technique is implemented. An ASG hardware along with its main functional circuits is designed, and the control software is developed. The ASG system is configured based on the loudspeakers used by the vehicle’s audio system and the frequency response characteristics of the loudspeakers is obtained by testing. An interior sound design method simulating acceleration conditions is investigated in detail. The control method is formulated based on the interior noise characteristics in accordance with the engine order sound amplitude variation. By establishing a design process with an ASG calibration and evaluation method, the accuracy of the acoustic synthetic method is validated. In summary, this work provides an interior sound design process to simulate accelerating conditions for electric vehicles and has established a sound control, calibration, and evaluation methodology for ASG systems.
Cao, Yuntao, Hou, Hangsheng, Liu, Yingjie, Tang, Lechao, Li, Yun
Tumble Flow Enhancement Applied for Low-Load Condition of Engines by Utilizing Reverse Flow Phenomenon in Intake Port2019-32-05091/24/2020
We established a technology that can enhance the tumble flow in the cylinder only in a partial load range of the engine without the need to use any intake path switching mechanisms. Firstly, we attempted to understand the basic phenomena of intake flow by using a CFD model, while using a butterfly throttle valve in a straight pipe. By doing this, we were able to observe the reverse flow of intake air that appears after the intake air has passed the throttle valve when the throttle valve opening is 30% or less. This reverse flow is generated mainly in the flow that has passed the trailing edge of the throttle valve. At both sides of the trailing edge opening, the flow is slowed down by diffusing. The flow is then pulled into the low-pressure zone created behind the throttle valve. In addition, a part of the reverse flow merges with the air flowing on the leading-edge side. Next, we confirmed that installing a flow separator behind the throttle valve that vertically divides the flow can successfully capture the reverse flow into one of the two flow paths. Furthermore, we confirmed that optimizing the separator position can capture most of the flow into one path, thereby gaining the required amount of flow that can generate tumble in the combustion chamber. By applying the above results to an actual engine, we validated the effect through a CFD flow analysis and also steady flow tests. As a result, we confirmed that this system can enhance tumble within a partial load range of the engine to a level that is equivalent to that obtained by a tumble port that has a flow path switching mechanism.
Nakamura, Yohei, Inoue, Yosuke, Fujikubo, Makoto
Effect of Fuel Composition in Bio-syngas on NOx in Emission with SI-ICE2019-32-06041/24/2020
In recent years, effective methods of utilizing power generation using biomass have been studied a biomass power generation with an internal combustion engines. It is able to be used even on small scale. In addition, by using the ICE, it is possible to make the efficiency relatively high. The compact downdraft type gasifier was manufactured. It generates bio-syngas from biomass. A small spark ignition ICE (SI-ICE) was drove using bio-syngas as fuel. NO is included in the emission of the ICE. Due to NO is said that it pollute the atmosphere and destroy the ozone layer, it must be reduced. Many researcher study NO in emission with synthetic gas of CH4 mixed with H2. Their result is NO increased as H2 ratio increased. However, experiments with actual syngas is few. And, combustible gases in bio-syngas produced by our equipment are CO, H2 and CH4. Previous studies with synthetic gas of mixed CO, H2 and CH4 is few. Therefore, experiments are performed with actual syngas. Also, H2 and city gas (13 A) is added to syngas for the purpose of changing the combustible gas composition. Also, thermal efficiency and operational stability were compared. COV-IMEP was used for operation stability. H2 and 13A were mixed in 2 inch hose. The experiment was conducted with same IMEP and excess air ratio. The experiment result was compared with syngas, syngas added H2 and syngas added CH4. It was that NO with bio-syngas was higher than 13A. NO in the emission was thermal NO. The maximum incylinder temperature and the heat release ratio increased when H2 was added. And initial and main combustion duration decreased. When CH4 was added, the result was the opposite of when H2 was increased. It is expected from this experiment that when bio-syngas is used, there will be the combustion duration in which the balance of NO emission and thermal efficiency is best.
Iwai, Shota, Fukadu, Kazushi, Enomoto, Hiroshi
Sound Quality Development Using Psychoacoustic Parameters with Special Focus on Powertrain Noise2020-01-50001/24/2020
This research uses vehicle interior noise at the driver position during full load acceleration to objectively define the resultant Sound Quality (SQ) of the vehicle analyzed by focusing on powertrain noise. A calculation method is developed to rank vehicles in order of customer preference (Sound Rank) and provide a subjective evaluation score for different error states a vehicle can encounter. In order to calculate these two scores, a pleasantness parameter is obtained using standard calculated psychoacoustic parameters with different weighting scores depending on their importance toward the preference ranking. Then pleasantness is correlated with jury test results and subjective evaluations. The results obtained show that the model is capable of quantifying the vehicle SQ during the vehicle development process and position a vehicle within a two-dimensional (2D) powerful-refined plot. This is achieved with the help of psychoacoustic parameter scatter bands. The model provides an objective tool to quantify and verify the resultant SQ to help meet and optimize Noise, Vibration, and Harshness (NVH) targets.
Victor, Garanto, Zhirong, Geng, Junfeng, Hu, Xiaolong, Deng, Wanli, Yang, Hao, Wang
Impact of Intake Port Water Injection Timing on Mitigating the Tradeoff between Performance and NO x Emissions for a Naturally Aspired Micro-CHP-Engine2019-32-05761/24/2020
Small natural gas cogeneration engines usually operate with lean mixture and late combustion phasing to comply with NOx emission standards, leading to significant losses in engine efficiency. Owing to water evaporation heat and high specific heat capacity of the water vapor, leads the water injection to cooling the combustion chamber charge, which enables earlier combustion phasing, higher compression ratio and thus higher engine efficiency. Therefore, water injection enables mitigating the tradeoff between NOx emissions and engine performance, without loss in engine efficiency. The intake port injection represents, because of the low required injection pressure and the simple injector integration, a cost-effective way to introduce water into the engine. Hence, the purpose of this work is to adapt the intake port water injection timing to the charge mixture flow conditions in the intake port. For this purpose, a variation of the injection timing was experimentally carried out on the engine test bench. The combustion phasing and the NOx emissions were kept constant. At the same time, the engine power, engine efficiency, temperatures in the intake port and mass flow rates were recorded. To gain a deeper insight into the complex processes in the intake port, such as spray-flow interaction, wallfilm formation and evaporation, 3D CFD simulations were conducted for three selected cases with different injection timings. For the 3D CFD Simulations, the spray model used, was tuned with help of spray pictures, taken on the spray test bed. Experimental investigations have shown that an injection close to the intake valve opening allows an increase in engine performance at constant NOx emissions without loss of engine efficiency. In fact, early injection allows effective cooling of the intake port mixture and allows part of the injected water to enter the combustion chamber as liquid and to vaporize there. A disadvantage of an injection close to the intake port opening, shown by the 3D CFD simulations, is that the water vapor is distributed homogeneously in the combustion chamber with a slightly higher concentration in the prechamber area, which could lead to a significant slowdown of the combustion speed, if the injected amount of water is increased.
Beltaifa, Youssef, Kettner, Maurice, Eilts, Peter, Klaissle, Markus
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 mixture. These two visualization techniques were used together to measure continuous combustion cycles. The fluctuation of net IMEP can be explained by the fluctuation of Turbulence Kinetic Energy (TKE) and fuel concentration. In most cycles, net IMEP was correlated with TKE. In the remaining cycles, net IMEP was correlated with fuel concentration. The contribution of each factor towards net IMEP is to be discussed. It has been also confirmed that TKE fluctuation is caused by fluctuation in the tumble vortex structure, as shown in the authors' previous study [2] [13].
HARAMIISHI, Santa, WATANABE, Takahiro, IIDA, Minoru, HOKIMOTO, Satoshi, KUBOYAMA, Tatsuya, MORIYOSHI, Yasuo
Energy Release Characteristics inside a Spark-Ignition Engine with a Bowl-in-Piston Geometry2020-01-50031/16/2020
The conversion of compression ignition (CI) internal combustion engines to spark-ignition (SI) operation by adding a spark plug to ignite the mixture and fumigating the fuel inside the intake manifold can increase the use of alternative gaseous fuels (e.g., natural gas) in heavy-duty applications. This study proposed a novel, less-complex methodology based on the inflection points in the apparent rate of heat release (ROHR) that can identify and separate the fast-burning stage inside the piston bowl from the slower combustion stage inside the squish region (a characteristic of premixed combustion inside a diesel geometry). A single-cylinder 2L CI research engine converted to natural gas SI operation provided the experimental data needed to evaluate the methodology, at several spark timings, equivalence ratios, and engine speeds. The results indicated that the end of the bulk combustion traditionally defined as the location of 90% energy release was not greatly affected by the change in operating conditions. Moreover, the actual duration of the rapid-burning stage was 60-80% shorter than the crank angle interval between 10% and 90% energy release. However, the fast-burning period (i.e., the start and the end of the rapid-burning stage) was well-characterized by the crank angle duration between the first and the second ROHR inflection points. Moreover, this novel methodology to characterize the combustion process suggested that the longer time interval between the end of fast-burn (i.e., the first ROHR inflection point) and the end of combustion was due to an important fuel fraction burning slower inside the squish region, which finally affects both efficiency and emissions of such converted engines.
Liu, Jinlong, Dumitrescu, Cosmin Emil
Feasibility Study of the Fuel Magnetizer in Flex-Fuel Cars2019-36-02381/13/2020
The topic of energy efficiency is currently a subject widely debated in industrial sectors because of its high relevance due to the finite life time of fossil fuels and the need for reduction in consumption and consequently the emissions of gases and the environmental impact. The objective of this work was to evaluate the performance of fuel magnetizers, a product marketed that, according to suppliers, guarantees an improvement in combustion efficiency, representing a saving of 10% to 22% of fuel. For the analysis of the efficiency of the magnetizer, consumption tests were carried out on engine test bench with and without the use of the product in idling speed, 2000 rpm and 2700 rpm. The conclusions obtained showed that the use of magnetizers did not achieve a satisfactory result in the efficiency of internal combustion engines, a possible factor responsible is the high content of ethanol in Brazilian gasoline.
Amorim, Pablo A., De N. Mattos, Luiz F., Almeida, Everton L. P., Pellacani, Gustavo C., Marques, Luiz A. M. M.
Variable Camshaft Valve Timing and its Effects to Hydrous Ethanol (E100) Combustion during Engine Warm up Phase2019-36-01471/13/2020
In-cylinder airflow has significant impact in mixture formation and burn in internal combustion engines. Exhaust valve closing retard and early intake valve opening have large contribution for the in-cylinder airflow. It may reduce pumping work (energy lost to pump exhaust gases out of the cylinder and to draw the fresh air-fuel mixture), hurt combustion stability due to the excess of residual gas in the combustion chamber or still contribute to cylinder scavenging, increasing the amount of fresh air resulting in higher burn efficiency and more work extracted from the cycle. Brazilian market has large Hydrous Ethanol fuel (E100) usage. Due to E100 fuel properties, the intake and exhaust valves opening and closing time must be carefully defined during the engine warm up phase to avoid negative effects on the combustion. The objective of this work is to analyze the effects in performance, combustion stability and emissions, of exhaust valve timing at different engine temperatures when using E100 fuel in a Ford 1.5L naturally aspirated 3-cylinder engine with Port Fuel Injection (PFI) and dual variable valve timing control. The study shows that it is possible to obtain significant emissions improvements during warm up phase by optimizing exhaust valve timing, without exceeding combustion stability limits.
Passarini, Gustavo C., Fregoneze, Marcos, Júnior, Fernando Sarracini
Engine calibration and driveability evaluation of a racecar2019-36-01261/13/2020
The passenger car automakers are always competing to excel in vehicle characteristics related to passenger comfort and driveability aspects. The engine calibration is a theoretical and experimental procedure with the intention to extract maximum efficiency from the engine and guarantee satisfactory levels of driving for both conventional and racing cars. This paper describes the calibration procedure of a Formula SAE race car engine. The engine was a four cylinder 600 cm3 four-strokes with modified intake and exhaust systems, controlled by an engine control unit (Motec M800 ECU). These engines present optimized characteristics for high speed, in exchange for some combustion degradation in some specific operating conditions at low speed that may impair vehicle driveability. Therefore, good tip-in reaction and the progression of the torque delivery are fundamental criteria to increase the vehicle performance, specially, to those submitted to short acceleration distances. The related criteria to the vehicle dynamic comfort has objective values to measure the abrupt engine speed transactions, jerks and acceleration variability related to torque variation. Improvement on such parameters can be obtained by means of main factors that influence in the combustion such as the air/fuel ratio control and the spark timing. In reality, the variations or instabilities in the torque delivery can be verified by analyzing instabilities in engine speed. This paper describes the direct approach with the aim of reducing temporal engine speed variability and compare it to the driveability criteria. Thus, accelerometers were used to quantify the vehicle longitudinal accelerations, decelerations and critical track conditions, such as low speed traction, to evaluate the engine calibration and correlate data in favor of the driveability and performance improvements.
Goulart, Aleff, Piccini, Alexandre, Müller, Alice, Balbom, Felipe, Martins, Mario, Carvalho, Pedro
Methodology to Determine the Fast Burn Period Inside a Heavy-Duty Diesel Engine Converted to Natural Gas Lean-Burn Spark Ignition Operation2019-01-222012/19/2019
The conversion of existing diesel engines to natural-gas operation can reduce the dependence on petroleum imports and curtail engine-out emissions. A convenient way to perform such conversion is by adding a gas injector in the intake manifold and replacing the diesel fuel injector with a spark plug to initiate and control the combustion process. However, challenges may appear with respect to engine’s efficiency and emissions as natural-gas spark-ignition combustion inside a diesel combustion chamber is different to that in conventional spark ignition engines. For example, major difference is the phasing and duration of the fast burn, defined as the period in which the rate of heat release increases linearly with crank angle. This study presents a methodology to investigate the fast burn inside a diesel geometry using heat release data. The algorithm was applied to experimental data from a single-cylinder research engine that operated at several lean-burn conditions that changed spark timing, equivalence ratio, and engine speed. More, a 3D CFD RANS engine simulation was used to validate the developed methodology. As results showed that the fast burn definition used for conventional spark ignition engines can produce errors when applied in retrofitted diesel engines, this methodology can help optimize engine conversion.
Liu, Jinlong, Dumitrescu, Cosmin
Injection Strategies for Isobaric Combustion2019-01-226712/19/2019
In a previous study, we demonstrated that the isobaric combustion cycle, achieved with a split injection strategy, can be more suitable for the double compression expansion engine concept than the conventional diesel combustion cycle. The present work is focused on understanding the effect of different injection strategies on the heat release, efficiency, and emissions of isobaric combustion at the peak cylinder pressure of 150 bar. In situ injection rate measurements are performed to improve our understanding of the heat release rate shape and pollutant formation. A variation of load is performed to demonstrate the feasibility of the isobaric combustion cycle at higher loads, and the means of achieving them. The thermal efficiency reduces at lower loads because of heat losses. It peaks at a medium load point before reducing again at higher loads because of exhaust losses. The effect of altering the injection strategy on the isobaric combustion cycle is also studied at a constant equivalence ratio. The alteration of injection strategy is proven to have minimal effect on efficiency, loss mechanisms, and emissions when more than one injection is used.
Babayev, Rafig, Houidi, Moez Ben, Shankar, VS Bhavani, Aljohani, Bassam, Johansson, Bengt
Enhancing Peak Firing Pressure Limit for Achieving Better Brake Thermal Efficiency of a Diesel Engine2019-01-218012/19/2019
An increased cycle expansion ratio is beneficial from a thermodynamic viewpoint to increase the engine efficiency. In this study, the target compression ratio and corresponding thermodynamic cycle layout were investigated by means of a new ideal combustion cycle. To model the experimental pressure traces, the combustion was divided into three parts; constant volume combustion, early expansion combustion and late combustion. This study discussed optimal parameter values for compression ignition combustion under PFP constraints. These parameters included compression ratio, pressure ratios as well as cut-off ratios. Furthermore, this study experimentally investigated the limitation of thermal efficiency and the variation of energy losses under different geometric compression ratios, boosting pressure and degree of constant volume combustion. These experiments utilized a supercharged single-cylinder heavy duty diesel engine with PFP-capability of up to 30 MPa. In conclusion, it is confirmed that improvement in the indicated thermal efficiency and BTE was achieved by increasing the compression ratio. The trade-off between increased compression ratio and higher losses was also established and an optimum compression ratio found.
Enya, Kenji, Uchida, Noboru
Evaluation of Cycle Variation of SWACER-like Knocking Using 3D SI Combustion Simulation2019-01-220812/19/2019
Cyclic variation on heavy knocking was reproduced using 3D SI combustion simulation with RANS / LES turbulence models and detailed kinetic mechanisms. A 0.66 liter, inline 3 cylinder gasoline engine operated at 1200 rpm, WOT was mainly investigated. It was revealed that the combination of RANS, Liu mech. and calculation over multiple cycles worked well. Detailed process of heavy-knock was also suggested and it was thought that SWACER-like mechanism had concerned. RANS could describe typical behavior of heavy-knock within the first 3 cycle calculation and it showed good agreement with both the actual engine measurement and LES calculation result.
Kuroki, Tomonori, Shima, Yuta, Ono, Yasuhisa, Serizawa, Takeshi
Scavenging Phenomena Based Post-oxidation in Exhaust Manifold of a Turbocharged Spark Ignition Engine2019-01-219712/19/2019
In this research, a novel methodology for the post-oxidation in a turbocharged spark ignition (SI) engine is proposed and investigated that can improve the emissions along with the reduction in turbo-lag. In this research, both simulation and experimental activities are performed. The 1-D simulation model was used for the identification of efficient scavenging. Thereafter, experimental validation tests for modeling and post oxidation were conducted on a 4-cylinder turbocharged SI engine. From the results, it was revealed that efficient scavenging and post-oxidation can be obtained at lower speed and higher load. The enthalpy in exhaust manifold increased due to the post-oxidation reaction which in turn increased the temperature and pressure of the exhaust gases and hence emissions reduced. Also, due to the increased enthalpy at turbine upstream, the turbocharger speed increased and as a consequence, reduction in the turbo-lag was observed. It was also noted that the post-oxidation is limited at higher load and overlap in an inline 4-cylinder engine due to the strong scavenging which increased the cooling effect in in-cylinder and exhaust manifold due to excess air.
Kumar, Madan, Kuboyama, Tatsuya, Hasegawa, Naohiro, Moriyoshi, Yasuo
Emission Prediction with Detailed Chemistry2019-01-221512/19/2019
Numerical modeling of engine combustion products requires detailed chemistry and therefore large computational resources and time. This becomes a constraint when engine optimization at system level is desired. In this paper, a 1D modeling approach is proposed for fast computation to predict emission level at various engine running conditions. A new chemical solver within 1D framework is developed along with suitable reduced chemical mechanism. The reduced reaction scheme is validated against detailed chemistry on 0D and 1D reactors. It is confirmed that the new fast 1D solver achieves more than 100X speed improvement. Now larger mechanisms can be used for better accuracy with reasonable turnaround time. This methodology allows virtual engine emission map generation, with a refined emission map completed within 12 hours of computational time. When a transient response is considered, the critical first 600 seconds of FTP driving cycle is calculated within 1 hour, based on a reduced fast running 1D model.
Shieh, Tenghua, Nitulescu, Oana, Uehara, Kazuhiro, Noguchi, Yasushi
Research of Fuel Components to Expand lean-limit in Super lean-burn condition2019-01-225712/19/2019
The thermal efficiency of internal combustion engines can be improved dramatically with the right combination of engine technology and fuel technology. Super lean-burn technology is attracting attention as a means of boosting thermal efficiency. However, there is a limit to how lean a fuel-air mixture can be before combustion becomes unstable or misfire occurs. The authors evaluated the effects of various chemical compositions on the lean limit under super lean-burn conditions. By changing the composition of the fuel, it was possible to achieve excess air ratios of over 2.0, resulting in high thermal efficiency.
Naiki, Taketora, Obata, Ken, Watanabe, Manabu, Yokomori, Takeshi, Iida, Norimasa
A reduced order turbocharging process model for manifold pressure control with EGR2019-01-221212/19/2019
A mean value turbocharged engine model is useful in terms of accuracy and convenience for fuel economy strategies or engine controller development. Turbocharging process is a feedback system with a positive gain, i.e. increasing exhaust work leads to increasing a cycle work. The gain of the feedback system is determined mainly by exhaust work ratio in a cycle and inertia of the turbine. The work ratio was investigated based on engine test with EGR. A turbocharging process model was obtained using the work ratio in a cycle and theoretical equations. The model is applied to investigate manifold absolute pressure response with EGR.
Togai, Kazuhide, Fujinaga, Naoto
Ignition Experiments by Nanosecond Repetitively Pulsed Discharges in Intense Turbulence for Super Lean Burn at Engine Condition2019-01-216012/19/2019
Ignition by Nanosecond Repetitively Pulsed Discharges (NRPD) at EXponential Increase of Minimum Ignition Energy (MIE-EXI) region under super lean SI engine conditions was studied. Fundamental experiments were conducted with a turbulent ignition test chamber with twin counter-rotating fans. The MIE-EXI region by arc discharge appeared over 6500 rpm of fan speed. In the MIE-EXI region (7000 rpm), successful ignition was achieved by establishing coupled ignition kernels with NRPD at 15 kHz although ignition was unsuccessful at 1 kHz. Results show that ignition by NRPD has potential advantages for lean burn applications. Preliminary engine test results with NRPD were also demonstrated.
Uesugi, Kodai, Morii, Youhi, Mukoyama, Taichi, Tezuka, Takuya, Hasegawa, Susumu, Nakamura, Hisashi, Takana, Hidemasa, Maruta, Kaoru, Yokomori, Takeshi, Iida, Norimasa
CI Methanol and Ethanol combustion using ignition improver2019-01-223212/19/2019
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
Effects of Spark Timing with Other Engine Operating Parameters on the Particulate Emissions of a Dualinjection Gasoline Engine During Warm-up Conditions2019-01-221412/19/2019
Gasoline direct injection (GDI) has been a mainstream technology due to its higher thermal efficiency and better power output. However, with increasingly stringent emission regulations introduced (EURO VI PN limits: 6 x l011#/km), high particulate matter (PM) emission of GDI engine has been a serious problem that limits its further development. Previous studies have found that cold-start and warm-up operation conditions play the dominant role in engine-out particulate emissions. In this paper, emission characteristics during the cold-start were first studied by controlling the coolant temperature. A Cambustion DMS500 fast particle spectrometer was employed to analyze the PM emissions. In order to reduce the engine-out emissions of cold-start, a dual injection system which combines port-fuel-injection (PFI) and direct-injection (DI) was applied in a four-cylinder gasoline engine. After that, this research mainly investigated the influences of spark timing on the engine-out emissions under constant DI injection ratio. The results indicated that with application of dual injection system, total PN emissions had decreased significantly by up to an order of magnitude compared with GDI engine, while the size distributions of both were similar, featured as bi-modal-shaped. As for the impacts of spark timing, it was observed that total PN emissions would decline with the delay of spark timing, as well as a notable reduction in the GMD. Besides, the proportion of PN in nucleation mode showed a trend to increase with the delay of spark. The experimental results obtained above may provide a new technical roadmap for PN emission reductions during warm up periods in the future GDI engines.
Tao, Jie, Xia, Chun, Mao, Kerang, Chen, Wenhao, Fang, Junhua, Huang, Zhen
Research of the High Altitude Control Strategy of the Piston Aero-engine Using Two-stage Turbocharger Coupled with single Supercharging System2019-01-221112/19/2019
Aiming at the high altitude operation problems for piston-type aero-engines and to improve the practical ceiling and high altitude dynamic performance, this thesis analyzes a controllable three-stage composite supercharging system, using a two-stage turbocharger coupled supercharger method. The GT-Power simulation model of a four-cylinder boxer engine was established, and the control strategy of variable flight height was obtained. The simulation research of engine performance from 0 to 20,000 meters above sea level has been carried out, which shows that the engine power is at the same level as the plain condition, and it could still maintain 85.28 percent of power even at the height of 20,000 meters, which meets the flight requirements of the aircraft.
Yao, Ye, Shi, Lei, Zhang, Zhe, Xiao, Maoyu, Liu, Mingwei, Tan, Jianwei
Two-Degree-of-Freedom Controller Design for Diesel Engine Airpath System Considering Dynamics of Turbocharger and Manifolds2019-01-232112/19/2019
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
Online Automatic Adaptation for Model-based Control of Diesel Engine2019-01-232012/11/2019
In this paper, an online automatic adaptation method for model-based control of a diesel engine is developed. Control-oriented models based on physics has been proposed as substitutes for conventional control methods to improve the performance of engine under real driving situation. Even such physical-rich models have fitting parameters and it is preferable to adapt the parameters according to the real-time operating condition. Therefore, an automatic adaptation method for the model is developed, and the method is based on neural network. The prediction accuracy of the model is evaluated by simulation and it is confirmed that the method can be applied online to a real engine by experiment.
CAO, Jianan, TAKAHASHI, Motoki, YAMASAKI, Yudai, KANEKO, Shigehiko
Engine Valve Train Dynamic Analysis using 1-D Simulation Approach2019-28-242211/21/2019
In order to reduce engine development timing and cost, a numerical calculation used to evaluate valve train systems. This paper discusses the work done on kinematic and dynamic analysis of Valve Train (VT) system of a diesel engine by using 1-D Ricardo Valdyn software. The goal is to meet optimum intake, exhaust valve timing requirement, maximize, valve open area and 30% over-speed requirement. Valve train model is prepared and inputs like mass and stiffness are estimated from 3-D model and finite element analysis, respectively. Simulation model is used for predicting valve bounce speed, valve displacement, cam-follower contact stress and strain in the rocker arm. Initially, Kinematic analysis is carried out to study the change in valve motion characteristics such as cam contour radius, tappet contact eccentricity etc. Further to this, dynamic analysis is carried out to assess forces and stresses on valve train components. Effect of cam tappet contact stresses, buckling load on push rod, spring surge, ratio of spring force to inertia force, valve seating velocity at increased speed condition etc. are discussed in detail. The optimized cam profile and ramp have improved overall valve dynamics in terms of valve seating velocity and valve seating force. The dynamic vibration described in this paper has been fully validated by measurement.
Nain, Ajay, Nene, Devendra
More sting for the STINGRAY19AUTP11_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
Study of Advanced Control Based on the RBF Neural Network Theory in Diesel Engine Speed Control03-13-01-000510/14/2019
Abstract Based on radial basis function (RBF) neural network (NN) theory, RBF-Proportional Integral Derivative (PID) diesel engine speed control is proposed. The algorithm has strong self-learning ability and strong adaptive ability, and is able to optimize the control parameters of the speed loop controller in real time. A series of simulations are carried out with different initial weights. Simulation results reveal that initial weights have little effect on RBF-PID control performance. A STM32 MCU-based controller is developed according to the calculation requirement. Experiments are carried out on a D6114 diesel engine generator to verify the proposed speed control algorithm. The simulation results are in agreement with the experimental results. The results show that the influence of initial weights on RBF-PID control algorithm is smaller than that on BP-PID control algorithm. When RBF-PID control algorithm is adopted, the steady speed fluctuation rate is 0.4%. When sudden load is carried out, the speed recovery time is 2.1 s and the instantaneous adjustment rate is 4.93%. When sudden unload simulation is carried out, the speed recovery time is 2.2 s and the instantaneous adjustment rate is 5.27%. Speed control performance of diesel engine has been greatly improved.
Zhao, Guo-Feng, Long, Yun, Ding, Shun-Liang, Yang, Li-Ping, Song, En-Zhe, Ma, Xiu-Zhen
Design and Development of Intake Ports for 2-Valve & 4-Valve Configurations for Heavy Duty Off-Highway Diesel Engine2019-28-004210/11/2019
Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimizing engineering costs. Development of diesel engines for off-highway application for different power segments need different intake port design solutions to optimise in-cylinder flow structure for efficient combustion. With adaptation of low pressure mechanical fuel injection system, intake port development becomes an important stage for reduction of emission formation at the source and improvement in fuel economy. In this paper, intake port design and development process is elaborated for two different power ratings of 75 hp and 120 hp of off-highway engine. 2-valve and 4-valve configurations are deployed for the same cylinder bore size. Considering the legislative emission limits for these two power segments of engines, intake port are designed for target swirl and flow performance within the same constraints of cylinder head bolting pattern and valve train actuation mechanism. Intake port designs are experimentally evaluated on steady state flow test rig using AVL paddle wheel method for swirl and flow coefficient performance. A detail numerical analysis is carried out using AVL FIRE CFD simulation software to study developed flow structure and interactions. An efficient design of 4-valve intake port is carried out with the aid of CFD analysis.
Tikar, Sameer, Malkhede, Dileep, Nandgaonkar, Milankumar
How to Improve SI Engine Performances by Means of Supercritical Water Injection2019-24-023510/7/2019
The efficiency of ICEs is strongly affected by exhaust gases and engine cooling system heat losses, which account for about 50% of the heat released by combustion. A promising approach is to transfer this exhaust heat to a fluid, like water, and inject it into the combustion chamber under supercritical conditions. In such a way, the recovered energy is partially converted into mechanical work, improving both engine efficiency and performance. A quasi-dimensional model has been implemented to simulate an SI engine with supercritical water injection. Specifically, a spark ignition ICE, four-stroke with Port Fuel Injection (PFI) has been considered. The model accounts for gas species properties, includes valves opening/closing, wall heat transfer, a water injection model and a combustion model. The influence of some injection parameters, i.e. Water/Fuel ratio (W/F), Start Of water Injection (SOI) and Water Injection Duration (WID), on engine performances and efficiency is discussed in details. The results show that an increase of W/F ratio has the strongest impact on the performances with respect to SOI and WID, i.e. higher W/F ratio, SOI closer to TDC and shorter WID provide a higher engine performance. For instance, with W/F ratio equal to 7 and water injected at 230 bar and 700 K, an increase of engine efficiency up to 11.5% is obtained. The parametric analysis is performed by injecting water when the chemical heat release is complete, in order to avoid the interaction between injected water and combustion. Finally, the effects of spark advance on water injection efficiency gain have been investigated. By advancing the spark timing the combustion heat release is advanced, hence the supercritical water can be injected earlier. This leads to an increase of efficiency gain with earlier SOI.
Cantiani, Antonio, Viggiano, Annarita, Magi, Vinicio
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