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A Numerical Investigation on VVA Influence on the Combustion Phase for Premixed Combustion Engine Under Partial Load Conditions

DMMM - Politecnico di Bari-Sergio Camporeale
DMMM - Politecnico di Bari, GNFM INDAM-Francesco Fornarelli
  • Technical Paper
  • 2020-37-0005
To be published on 2020-06-23 by SAE International in United States
Nowadays, the vehicle hybridization and the use of more clean fuel in heavy-duty applications brings to a new beginning in the use of spark ignition engine. In standard intake system, the pre-mixed fuel air mixture is controlled by the injection of fuel after the throttle valve. Then, intake system, consisting in intake duct, valve number and geometry and cylinder head shape influence the characteristics of the intake flow within the cylinder up to the ignition of the combustion by the spark plug. The technology advancement in fluid-power and electrical actuation gives the opportunity to decouple the intake and exhaust valve actuation with respect to the standard cam shaft distribution. The Variable Valve Actuation (VVA) concepts is not new, but its application is now affordable and flexible enough to be applied in partial load conditions. Here, by means of three-dimensional numerical simulations the intake and combustion process is studied with a finite volume approach to solve the mass, momentum and energy equations together with an Extended Coherent Flamelet Model (ECFM). Two different approaches in driving the…
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Impact of fuel octane quality on various advanced vehicle technologies

Shell Global Solutions (Deutschland)-Caroline Magdalene Zinser, Patrick Haenel
Shell Global Solutions (UK)-Alastair Smith
  • Technical Paper
  • 2020-01-0619
To be published on 2020-04-14 by SAE International in United States
Fuel with higher octane content is playing a key role in optimising engine performance by allowing a more optimal spark timing which leads to increased engine efficiency and lower CO2 emissions. In a previous study the impact of octane was investigated with a vehicle fleet of 20 vehicles using market representative fuels, varying from RON 91 to 100. The resulting data showed a clear performance and acceleration benefit when higher RON fuel was used. In this follow-up study 10 more vehicles were added to the database. The vehicle fleet was extended to be more representative of Asian markets, thus broadening the geographical relevance of the database, as well as adding vehicles with newer technologies such as boosted down-sized direct injection engines, or higher compression ratio engines. Eight different fuel combinations varying in RON were tested, representing standard gasoline and premium gasoline in different markets around the world. The new results augment our previously published octane study and result in a vehicle fleet dataset comprising 30 cars from 18 different automotive manufactures. Two key metrics were…
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Electronic Control of Brake and Accelerator Pedals for Precise Efficiency Testing of Electrified Vehicles

Southwest Research Institute-Michael C. Gross, Jonathan Hamermesh, Kyle Jonson, Joshua Alden
  • Technical Paper
  • 2020-01-1282
To be published on 2020-04-14 by SAE International in United States
Efficiency testing of hybrid-electric vehicles is challenging, because small run-to-run differences in pedal application can change when the engine fires or the when the friction brakes supplement regenerative braking, dramatically affecting fuel use or energy regeneration. Electronic accelerator control has existed for years, thanks to the popularity of throttle-by-wire (TBW). Electronic braking control is less mature, since most vehicles don’t use brake-by-wire (BBW). Computer braking control on a chassis dynamometer typically uses a mechanical actuator (which may suffer backlash or misalignment) or braking the dynamometer rather than the vehicle (which doesn’t yield regeneration). The growth of electrification and autonomy provides the means to implement electronic brake control. Electrified vehicles use BBW to control the split between friction and regenerative braking. Automated features, e.g. adaptive cruise control, require BBW to actuate the brakes without pedal input. We present a system for computer control of brake and accelerator inputs on a TBW- and BBW-equipped vehicle. The system injects analog signals into the vehicle’s wiring harness, bypassing the pedals and obviating mechanical actuation and brake-by-dyno. The system combines…
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Experimental Study on Thermal Management Strategy of the Exhaust Gas of a Heavy-Duty Diesel Engine Based on In-Cylinder Injection Parameters

Tongji University-Piqiang Tan, Lishuang Duan, Erfeng Li, Zhiyuan Hu, Diming Lou
  • Technical Paper
  • 2020-01-0621
To be published on 2020-04-14 by SAE International in United States
The aftertreatment system is indispensable for the removal of the noxious pollutants emitted by diesel engines, whose efficiency depends largely on the exhaust gas temperature. Therefore, this study proposes a thermal management strategy including post injection, intake throttling and late post injection to improve the efficiency of the aftertreatment system for a heavy-duty diesel engine. In the experiments, the effects of main injection, post injection, injection pressure and throttle opening on the exhaust gas temperature at diesel oxidation catalyst (DOC) inlet were studied, with the influence of late post injection on the exhaust gas temperature at DOC outlet also investigated. The results showed that the reasonable control of throttle opening and post injection (such as the adjustment of injection timing and injection quantity) can significantly improve the average temperature at DOC inlet from 237.8°C to 333.6°C in the WHTC, with an increase of 40.3%. On the contrary, the influence of main injection timing on the temperature at DOC inlet was very limited, and reducing injection pressure can slightly raise the temperature at DOC inlet, which,…
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The Potential of Gasoline Fueled Pre Chamber Ignition Combined with Elevated Compression Ratio

Hitachi Europe GmbH-Henning Sauerland
Technische Universitat Munchen-Andreas Stadler, Martin Härtl, Georg Wachtmeister
  • Technical Paper
  • 2020-01-0279
To be published on 2020-04-14 by SAE International in United States
Pre-chamber ignition is a method to simultaneously increase the thermal efficiency and to meet ever more stringent emission regulations at the same time. In this study, a single cylinder research engine is equipped with a tailored pre-chamber ignition system and operated at two different compression ratios, namely 10.5 and 14.2. While most studies on gasoline pre-chamber ignition employ port fuel injection, in this work, the main fuel quantity is introduced by side direct injection into the combustion chamber to fully exploit the knock mitigation effect. Different pre-chamber design variants are evaluated considering both unfueled and gasoline-fueled operation. As for the latter, the influence of the fuel amount supplied to the pre-chamber is discussed. Due to its principle, the pre-chamber ignition system increases combustion speeds by generating enhanced in-cylinder turbulence and multiple ignition sites. This property proves to be an effective measure to mitigate knocking effects. It is shown that less spark retard compared to conventional spark ignition allows to exploit the efficiency benefit of elevated compression ratios also in high load operation for stoichiometric mixtures.…
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Starting Process Control of a 2-Cylinder PFI Gasoline Engine for Range Extender

Tongji University-Minglong Li, Ran Zhang, Xingyu Zeng, Weiqi Ding, Weiang Mao, Shaoye Jin, Rufeng Xu, Dengke Yuan, Zongjie Hu, Zaimin Zhong, Liguang Li
  • Technical Paper
  • 2020-01-0315
To be published on 2020-04-14 by SAE International in United States
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…
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Measurement of Fuel Distribution in a Small PFI Spark-Ignition Engine Using Tracer PLIF

Indian Institute of Technology Madras-Shubham Garg, Mayank Mittal, Srikrishna Sahu
TVS Motor Co., Ltd.-V Lakshminarasimhan
  • Technical Paper
  • 2020-01-0786
To be published on 2020-04-14 by SAE International in United States
The distribution of fuel-air mixture inside the engine cylinder strongly influences the combustion process. Planar laser-induced fluorescence (PLIF) is commonly used for fuel distribution measurement, however, it is mostly reported on moderate- to large-sized engines. In the present work, PLIF is applied to measure the fuel distribution inside the cylinder of a small, four-stroke, port-fuel-injection (PFI), spark-ignition engine with displacement volume of 110 cm3. Iso-octane was used as the base fuel, and 3-pentanone (15% by volume) was added as a fluorescent tracer in the base fuel. The effect of equivalence ratio, considering ϕ = 1.2, 1.0, and 0.8, on in-cylinder fuel distribution was studied with low throttle opening of 25% at 1200 rpm. PLIF images were recorded at different crank angle degrees during both intake and compression strokes over a swirl measurement plane located at the TDC position. It was found that the fuel stratification was present from intake to even late compression. Also, no significant change in fuel distribution patterns was noted at different crank angle degrees for a given operating condition. Instantaneous PLIF…
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Quantifying Engine Braking for Various Common Street Motorcycles

Collision and Injury Dynamics, Inc.-Henricus Jansen, Beau LeBlanc, Christopher Wilhelm, Tyler Shaw, Alvin Lowi
  • Technical Paper
  • 2020-01-0880
To be published on 2020-04-14 by SAE International in United States
Motorcycle engine braking will be measured in each forward gear for a cross-section of typical street motorcycles. Using GPS data acquisition and video, curves will be developed showing deceleration relative to engine speed, ground speed, distance, and time. Motorcycle characteristics will include low, middle, and high displacement sport, V-twin two-cylinder cruiser, single-cylinder adventure, three-cylinder, and shaft-driven. Motorcycles will be accelerated to approximately 70 mph when achievable in the respective gear, and throttle will be abruptly closed. The motorcycles will cruise unbraked until 15 to 30 kilometers per hour. For control, each motorcycle will be accelerated to the test speed and shifted to neutral to measure combined wind and rolling resistance. Tests will be performed on level ground and in opposing compass directions to account for wind. The data acquired will give more insight to what extent engine braking is a factor for accident reconstruction. Further, it will show the variability between frictional losses for different types of motorcycle powertrains and drivetrains.
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Strategy for Optimizing an F1 Car’s Performance based on FIA Regulations

Oxford Brookes University-Karan Bopaiah, Stephen Samuel
  • Technical Paper
  • 2020-01-0545
To be published on 2020-04-14 by SAE International in United States
With the introduction of the V6 engines in Formula 1, in 2014, the sport aimed to close the gap between the automotive engine and high-performance motorsport engines in the area of fuel economy. A set of very challenging engineering regulations were introduced by the FIA to restrict the power from the Internal Combustion Engine (ICE), while allowing for more power to be harvested through energy recovery systems. Although progress has been made in developing a highly efficient powertrain, the limit to which this system can be pushed to is still unknown due to a significant gap between the technological choices available and the optimal control strategy used. This study investigated an engine-powertrain model of an F1 car with real world driver data for estimating the vehicle’s full throttle performance. The work used engine and drive-cycle simulation-modeling tools to build a representative car model which complied with the 2019 FIA regulations, in conjunction with real world data to identify the most critical parameter such as the gear shift strategy and the maximum energy recovered, stored and…
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Effects of Injection Pressure, Intake Throttling, and Cylinder Deactivation on Fuel Consumption and Emissions for a Light Duty Diesel Engine at Idle Conditions

University of Texas-Meng Lyu, Yousif Alsulaiman, Corey Tambasco, Matthew Hall, Ron Matthews
  • Technical Paper
  • 2020-01-0303
To be published on 2020-04-14 by SAE International in United States
The continuing growth of urban population centers has led to increased traffic congestion for which vehicles can spend considerable periods at low speed/low load and idle conditions. For light-duty diesel vehicles, these low load conditions are characterized by low engine exhaust temperatures (~100oC). Exhaust temperatures can be too low to maintain the activity of the catalytic exhaust aftertreatment devices (usually need >~200oC) which can lead to high emissions that contribute to deteriorating urban air quality. This study is a follow-on to two previous studies on the effects of throttling, post-injection, and cylinder deactivation (CDA) on light-duty diesel engine exhaust temperatures and emissions. The focus of the present study is on fuel consumption, exhaust temperatures, and emissions with and without cylinder deactivation or with fuel cutout, and the sensitivity to or effects of fuel rail pressure, along with observations of apparent idle engine friction.The baseline injection strategy was adapted from a 2014 Chevrolet Cruze having an engine similar to the light-duty 2.0 liter GM engine used for this study. All measurements were made under idle conditions…