Your Selections

Boost pressure
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

 

Glossary of Engine Cooling System Terms

Cooling Systems Standards Committee
  • Ground Vehicle Standard
  • J1004_201904
  • Current
Published 2019-04-22 by SAE International in United States
The objective of this glossary is to establish uniform definitions of parts and terminology for engine cooling systems. Components included are all those through which engine coolant is circulated: water pump, engine oil cooler, transmission and other coolant-oil coolers, charge air coolers, core engine, thermostat, radiator, external coolant tanks, and lines connecting them.
Datasets icon
Annotation icon
 

Optimization of a Diesel Engine with Variable Exhaust Valve Phasing for Fast SCR System Warm-Up

University of Michigan-Pavan Kumar Srinivas, Rasoul Salehi
Published 2019-04-02 by SAE International in United States
Early exhaust valve opening (eEVO) increases the exhaust gas temperature by faster termination of the power stroke and is considered as a potential warm up strategy for diesel engines aftertreatment thermal management. In this study, first, it is shown that when eEVO is applied, the engine main variables such as the boost pressure, exhaust gas recirculation (EGR) and injection (timing and quantity) must be re-calibrated to develop the required torque, avoid exceeding the exhaust temperature limits and keep the air fuel ratio sufficiently high. Then, a two-step procedure is presented to optimize the engine operation after the eEVO system is introduced, using a validated diesel engine model. In the first step, the engine variables are optimized at a constant eEVO shift. In the second step, optimal eEVO trajectories are calculated using Dynamic Programming (DP) for a transient test cycle. The optimized results indicate that with early EVO, the boost pressure should be increased to provide enough cylinder air charge and to maintain the engine torque. External EGR can be reduced due to increased internal EGR…
Annotation icon
 

Effect of Diamond-Like Carbon Coating on Anti-Scuffing Characteristics of Piston Pins

Hino Motors, Ltd.-Shoichiro Usui, Hideki Kato, Hiroshi Nakajima, Kiyohiro Shimokawa
Published 2019-04-02 by SAE International in United States
It has been proposed that downspeeding combined with high boost levels would effectively reduce fuel consumption in heavy-duty diesel engines. Under low-speed and high-boost operating conditions, however, the in-cylinder gas pressure, which acts on the piston crown, is greater than the piston inertia force (such that there is no force reversal), over the entire range of crank angles. Therefore, the piston pin never lifts away from the main loading area (the bottom) of the connecting rod small-end bushing where the contact pressure against the piston pin is highest. In such operating conditions, lubricant starvation is easily induced at the interface between the piston pin and small-end bushing. Through carefully devised engine tests, the authors confirmed that the piston pin scuffing phenomenon arises when the boost pressure exceeds a critical value at which the no-force reversal condition appears. Furthermore, to prevent this piston pin scuffing when there is no force reversal, the authors applied a type of diamond-like carbon (DLC), a hydrogenated tetrahedral amorphous carbon (ta-C:H) coating, to the piston pins and then evaluated its anti-scuffing…
Datasets icon
Annotation icon
 

Steady-State, Transient and WLTC Drive-Cycle Experimental Performance Comparison between Single-Scroll and Twin-Scroll Turbocharger Turbine

Imperial College London-Ricardo Martinez-Botas
Mitsubishi Heavy Industries Engine & Turbochargers-Motoki Ebisu
Published 2019-04-02 by SAE International in United States
The use of twin-scroll turbocharger turbine in automotive powertrain has been known for providing better transient performance over conventional single-scroll turbine. This has been accredited to the preservation of exhaust flow energy in the twin-scroll volute. In the current study, the performance comparison between a single and twin-scroll turbine has been made experimentally on a 1.5L passenger car gasoline engine. The uniqueness of the current study is that nearly identical engine hardware has been used for both the single and twin-scroll turbine volutes. This includes the intake and exhaust manifold geometry, turbocharger compressor, turbine rotor and volute scroll A/R variation trend over circumferential location. On top of that, the steady-state engine performance with both the volutes, has also been tuned to have matching brake torque. Such highly comparable setup enabled a more precise evaluation on the effect of pulse-isolation in the twin-scroll turbine volute during transient process. The steady-state performance comparison shows the amplitude of exhaust pulse in the twin-scroll volute is substantially higher than in the single-scroll volute, hence confirming the preservation of pulse…
Datasets icon
Annotation icon
 

System Level 1-D Analysis of an Air-System for a Heavy-Duty Gasoline Compression Ignition Engine

Aramco Research Center-Praveen Kumar, Yuanjiang Pei, Michael Traver
BorgWarner Turbo Systems-John Watson
Published 2019-04-02 by SAE International in United States
A detailed study of various air system configurations has been conducted for a prototype gasoline compression ignition (GCI) engine using a Cummins MY2013 ISX15 heavy-duty diesel engine as the base platform. The study evaluated the configurations with the assumption that RON80 gasoline would be used as the fuel and the combustion chamber would have a geometric compression ratio (CR) of 16.5.Using 3-D computational fluid dynamics (CFD) simulations, a high efficiency & low engine-out NOx GCI combustion recipe was developed across the five engine operating points from the heavy-duty Supplemental Emissions Test (SET) cycle: A100, B25, B50, B75, and C100. The CFD generated air-thermal boundary conditions and the combustion burn-rate & injector rate-of-injection profiles were imported into a calibrated 1-D engine model for the air-handling systems analysis. For the RON80 GCI concept, an engine-out NOx range 1-1.5 g/kWh was targeted and this drove a need for higher boost pressure and EGR rates with intake temperatures in the 65°C-70°C range. The production air system comprising a single stage turbocharger and a high-pressure exhaust gas recirculation (HPEGR) system…
Datasets icon
Annotation icon
 

Preliminary Testing of n-Butanol HCCI on High Compression Ratio Diesel Engines

Shanghai Jiao Tong University-Tie Li
University of Windsor-Simon Leblanc, Prasad Divekar, Xiaoye Han, Jimi Tjong, Ming Zheng
Published 2019-04-02 by SAE International in United States
The control of combustion phasing in homogeneous charge compression ignition (HCCI) combustion is investigated with neat n-butanol in this work. HCCI is a commonly researched combustion mode, owing to its improved thermal efficiency over conventional gasoline combustion, as well as its lower nitrogen oxide (NOx) and particulate matter emissions compared to those of diesel combustion. Despite these advantages, HCCI lacks successful widespread implementation with conventional fuels, primarily due to the lack of effective combustion phasing control. In this preliminary study, chemical kinetic simulations are conducted to study the auto-ignition characteristics of n-butanol under varied background pressures, temperatures, and dilution levels using established mechanisms in CHEMKIN software. Increasing the pressure or temperature lead to a shorter ignition delay, whereas increasing the dilution by the application of exhaust gas recirculation (EGR) leads to a longer ignition delay. These ignition delay simulation results are used as a guide for the experimental study of n-butanol HCCI combustion on engine tests. Experiments are conducted near engine mid-load (~7 bar IMEP) on two engines with high compression ratios (i.e. 16.2:1 and…
Datasets icon
Annotation icon
 

A Physics-Based, Control-Oriented Turbocharger Compressor Model for the Prediction of Pressure Ratio at the Limit of Stable Operations

Ohio State University-Alexandra Taylor, Marcello Canova
Universita Degli Studi Di Genova-Anna Misley
Published 2019-04-02 by SAE International in United States
Downsizing and boosting is currently the principal solution to reduce fuel consumption in automotive engines without penalizing the power output. A key challenge for controlling the boost pressure during highly transient operations lies in avoiding to operate the turbocharger compressor in its instability region, also known as surge. While this phenomenon is well known by control engineers, it is still difficult to accurately predict during transient operations. For this reason, the scientific community has directed considerable efforts to understand the phenomena leading to the onset of unstable behavior, principally through experimental investigations or high-fidelity CFD simulations. On the other hand, less emphasis has been placed on creating control-oriented models that adopt a physics-based (rather than data-driven) approach to predict the onset of instability phenomena.This work describes a centrifugal compressor model that focuses on predicting the behavior at operating conditions close to the stability limit. The objective of the model is to facilitate the development of estimation and control algorithms to optimize the boost pressure in a wider set of operating conditions. The model captures some…
Datasets icon
Annotation icon
 

Optimizing Steady State Diesel Efficiency and Emissions Using a SuperTurboTM on an Isuzu 7.8L Engine

Isuzu Motors Ltd.-Tomoyuki Itou
SuperTurbo Technologies Inc.-Barry Suelter, Thomas Waldron, Jared Brin
Published 2019-04-02 by SAE International in United States
A driven turbocharger offers many benefits for internal combustion engines over traditional turbochargers or superchargers. One type of driven turbocharger, a SuperTurbo, is an amalgamation of supercharger, turbocharger, and turbo-compounder all in one device. This is accomplished through the combination of a high-speed traction drive that transfers bi-directional torque between the turbo shaft and a CVT, which then allows for overall ratio control between the turbo and the crankshaft. High efficiency turbine designs become feasible through the removal of overspeed and turbo lag design restrictions. Isuzu recognized the benefits of a driven turbocharger and the two companies have worked to evaluate it against more conventional turbochargers. This paper documents years of simulation, development, and engine testing, with a focus on steady state optimization of a 7.8L diesel engine. While improved transient response and drive cycle efficiency have previously been published, this paper will explain how the driven turbocharger functions differently than a normal turbocharger and how it improved steady state performance by precisely controlling and balancing boost pressure, air fuel ratio, high pressure EGR, and…
Datasets icon
Annotation icon
 

Variation in Squish Length and Swirl to Reach Higher Levels of EGR in a CNG Engine

AVL MTC AB-Ludvig Adlercreutz
KTH Royal Institute of Technology-Andreas Cronhjort
Published 2019-01-15 by SAE International in United States
Gaseous methane fuel for internal combustion engines have proved to be a competitive source of propulsion energy for heavy duty truck engines. Using biogas can even reduce the carbon footprint of the truck to near-zero levels, creating fully environmentally friendly transport. Gas engines have already been on the market and proved to be a popular alternative for buses and waste transport. However, for long haulage these gas engines have not been on par with the equivalent diesel engines. To improve the power and efficiency of EURO VI gas engines running stoichiometrically, a direct way forward is adding more boost pressure and spark advance in combination with more EGR to mitigate knock. Using in-cylinder turbulence to achieve higher mixing rate, the fuel can still be combusted efficiently despite the increased fraction of inert gases. In this paper, previous findings on in-cylinder air flows for diesel engine simulations are investigated for the applicability on to stoichiometric gas combustion. Two key parameters were identified, swirl and squish. By varying the levels of swirl with different squish lengths in…
Datasets icon
Annotation icon
 

Mechanism Analysis on the Effect of Fuel Properties on Knocking Performance at Boosted Conditions

Nissan Motor Co., Ltd.-Masaharu Kassai, Cagdas Aksu, Taisuke Shiraishi
Shell Global Solutions-Roger Cracknell
Published 2019-01-15 by SAE International in United States
In recent years, boosted and downsized engines have gained much attention as a promising technology to improve fuel economy; however, knocking is a common issue of such engines that requires attention.To understand the knocking phenomenon under downsized and boosted engine conditions deeply, fuels with different Research Octane Number (RON) and Motor Octane Number (MON) were prepared, and the knocking performances of these fuels were evaluated using a single cylinder engine, operated under a variety of conditions.Experimental results showed that the knocking performance at boosted conditions depend on both RON and MON. While higher RON showed better anti-knocking performance, lower MON showed better anti-knocking performance. Furthermore, the tendency for a reduced MON to be beneficial became stronger at lower engine speeds and higher boost pressures, in agreement with previously published modelling work.A new method of interpreting octane appetite is presented which relates the gradient of contour lines of MB50 in RON/MON space to K value.The results can be further interpreted by understanding the relative contribution of low temperature oxidation (LTO) pathways under the prevailing temperature/pressure conditions…
Datasets icon
Annotation icon