Engine Calibration Using “Eigenvariables”

2017 ◽  
Author(s):  
Yiran Hu ◽  
Ibrahim Haskara ◽  
Chen-Fang Chang ◽  
Kaveh Khodadadi Sadabadi ◽  
Ayyoub Rezaeian ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Development Process ◽  
Operating Conditions ◽  
Vehicle Design ◽  
Combustion System ◽  
Design Constraints ◽  
Engine Calibration ◽  
Engine Control System ◽  
Engine Combustion ◽  
Vehicle Development Process

To meet the more stringent emissions and fuel economy regulations, engine control system has become significantly more complex than before. As a result of this, engine calibration on the dynamometer now occupies one of the longest time sections in the vehicle development process. One strategy automakers have adopted is to use the same engine in multiple applications to reduce the calibration effort. Even then, vehicle design constraints often require changes to be made to the engine’s external components such as the intake and exhaust manifolds. These changes can create variations in the engine combustion behavior so that the engine must be recalibrated on the dyno, resulting in additional cost and effort. This paper explores the potential of reusing existing engine dyno data for a modified engine in these scenarios through the use of the so-called eigenvariable to describe engine operating conditions. Traditionally, engine dyno data is referenced by engine load and speed along with actuator positions (such as camphaser positions). The proposed approach describes dyno data using eigenvariables or variables that describe the engine in-cylinder condition prior to combustion. Eigenvariables are invariant with respect to external engine hardware. This invariance enables the same dyno data to be applied to a modified engine with the same combustion system design.

The Sampling of Rocket Combustion Gases

1964 ◽  
Vol 68 (647) ◽  
pp. 759-764
Author(s):  
R. Bryan
Keyword(s):  
Combustion Chamber ◽  
Rocket Engine ◽  
Operating Conditions ◽  
Combustion System ◽  
Combustion Chambers ◽  
Ratio Distribution ◽  
Mixture Ratio ◽  
Combustion Gases ◽  
Engine Combustion ◽  
Combustion Phase

Summary:—In the past, attempts have been made to evaluate injectors for rocket engine combustion chambers by the use of water analogy rigs and model combustion systems that simulated the injection and combustion phase change occurring in the actual engine. To confirm that conditions in the engine were being correctly simulated, a technique was evolved for determining the mixture ratio distribution achieved by the combustion system of a Spectre variable thrust rocket engine. Gas samples extracted from the rocket-efflux were analysed, and the technique has been applied to evaluate the Spectre's standard central mushroom type injector and also a multi-head injector.Tests have been conducted over a thrust range of 2000 lb to 8000 lb and at oxidant/fuel ratios from 7·5 to 13·0.In parallel with this external sampling, a probe has been designed and developed for extracting gas samples from selected points across a diameter of the combustion chamber itself. This probe has been successfully operated for several minutes under combustion conditions of 500 p.s.i.a. and 2600°K, without sustaining any damage.Analysis of the oxidant/fuel ratio pattern within the combustion chamber and in the efflux, at comparable operating conditions, indicates that little change in distribution occurs between these two points of the system. Also, the distribution found with the standard injector was that for which the combustion system was designed. It is demonstrated that loss of performance depends on the degree of non-uniformity of mixing. A 5 per cent loss in performance at full thrust and optimum mixture ratio occurs with the standard injector.

scholarly journals A Comparative Study on Fault Detection Methods for Gas Turbine Combustion Systems

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 389
Author(s):  
Jinfu Liu ◽  
Zhenhua Long ◽  
Mingliang Bai ◽  
Linhai Zhu ◽  
Daren Yu
Keyword(s):  
Fault Detection ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Detection Methods ◽  
Distribution Model ◽  
Outlet Temperature ◽  
Combustion System ◽  
Comparison Results ◽  
Gas Turbine Combustion

As one of the core components of gas turbines, the combustion system operates in a high-temperature and high-pressure adverse environment, which makes it extremely prone to faults and catastrophic accidents. Therefore, it is necessary to monitor the combustion system to detect in a timely way whether its performance has deteriorated, to improve the safety and economy of gas turbine operation. However, the combustor outlet temperature is so high that conventional sensors cannot work in such a harsh environment for a long time. In practical application, temperature thermocouples distributed at the turbine outlet are used to monitor the exhaust gas temperature (EGT) to indirectly monitor the performance of the combustion system, but, the EGT is not only affected by faults but also influenced by many interference factors, such as ambient conditions, operating conditions, rotation and mixing of uneven hot gas, performance degradation of compressor, etc., which will reduce the sensitivity and reliability of fault detection. For this reason, many scholars have devoted themselves to the research of combustion system fault detection and proposed many excellent methods. However, few studies have compared these methods. This paper will introduce the main methods of combustion system fault detection and select current mainstream methods for analysis. And a circumferential temperature distribution model of gas turbine is established to simulate the EGT profile when a fault is coupled with interference factors, then use the simulation data to compare the detection results of selected methods. Besides, the comparison results are verified by the actual operation data of a gas turbine. Finally, through comparative research and mechanism analysis, the study points out a more suitable method for gas turbine combustion system fault detection and proposes possible development directions.

Vehicle Thermal Management Simulation Using a Rapid Omni-Tree Based Adaptive Cartesian Mesh Generation Methodology

2004 ◽  
Author(s):  
Kumar Srinivasan ◽  
Z. J. Wang ◽  
Wei Yuan ◽  
Richard Sun
Keyword(s):  
Thermal Management ◽  
Mesh Generation ◽  
Development Process ◽  
Cfd Simulation ◽  
New Method ◽  
Surface Mesh ◽  
Passenger Vehicle ◽  
Traditional Approaches ◽  
Volume Mesh ◽  
Vehicle Development Process

CFD simulation of vehicle under-hood and under-body poses several challenges. Specifically, the complexity of the geometry involved makes the use of traditional mesh generation approaches, based on the boundary-to-interior methodology, impractical and time consuming. The current work presents the use of an interior-to-boundary method wherein the need for creating a ‘water-tight’ surface mesh is not a pre-requisite for volume mesh generation. The application of the new method is demonstrated for an actual passenger vehicle under-hood model with nearly a hundred components. Coupled radiation/convection simulations are performed to obtain the complete airflow and thermal map of the engine compartment. Results are validated with test data. The new method results in significant gains in efficiency over traditional approaches allowing the simulation tool to be used effectively in the vehicle development process.

Design and Performance of a Controlled Turbocharging System on Marine Diesel Engines

2006 ◽  
Author(s):  
Ioannis Vlaskos ◽  
Ennio Codan ◽  
Nikolaos Alexandrakis ◽  
George Papalambrou ◽  
Marios Ioannou ◽  
...  
Keyword(s):  
Steady State ◽  
Engine Performance ◽  
Operating Conditions ◽  
Electric Actuator ◽  
Engine Simulation ◽  
Engine Control System ◽  
Turbocharging System ◽  
Compressor Impeller ◽  
Marine Diesel ◽  
And Performance

The paper describes the design process for a controlled pulse turbocharging system (CPT) on a 5 cylinder 4-stroke marine engine and highlights the potential for improved engine performance as well as reduced smoke emissions under steady state and transient operating conditions, as offered by the following technologies: • controlled pulse turbocharging, • high pressure air injection onto the compressor impeller as well as into the air receiver, and • an electronic engine control system, including a hydraulic powered electric actuator. Calibrated engine simulation computer models based on the results of tests performed on the engine in its baseline configuration were used to design the CPT components. Various engine tests with CPT under steady state and transient operating conditions show the engine optimization process and how the above-mentioned technologies benefit engine behavior in both generator and propeller law operation.

Double Scroll Turbine for Automotive Applications: Engine Operating Point Versus Dynamic Blade Stress From Forced Response Vibration

2018 ◽  
Author(s):  
David Hemberger ◽  
Roberto De Santis ◽  
Dietmar Filsinger
Keyword(s):  
Pulse Energy ◽  
Internal Combustion Engines ◽  
Forced Response ◽  
Operating Conditions ◽  
Blade Vibration ◽  
Structural Dynamic ◽  
Vibration Excitation ◽  
Engine Combustion ◽  
Operating Points ◽  
Combustion Cycle

As a means of meeting ever increasing emissions and fuel economy demands car manufacturers are using aggressive engine downsizing. To maintain the power output of the engine turbocharging is typically used. Compared to Mono scroll turbines, with a multi-entry system the individual volute sizing can be better matched to the single mass flow pulse from the engine cylinders. The exhaust pulse energy can be better utilised by the turbocharger turbine improving turbocharger response. Additionally the interaction of the engine exhaust pulses can be better avoided, improving the scavenging of the engine. Besides the thermodynamic advantages, the multi-entry turbine represents a challenge to the structural dynamic design of the turbine. A higher number of turbine wheel resonance points can be expected during operation. In addition, the increased use of exhaust pulse energy leads to a distinct accentuation of the blade vibration excitation. Using validated engine models, the interaction of the multi-entry turbine with the engine has been analyzed and various operating points, which may be critical for the blade vibration excitation, have been classified. These operating points deliver the input variables for unsteady computational flow dynamics (CFD) analyses. From these calculations unsteady blade forces were derived providing the necessary boundary conditions for the structural dynamic analyses by spatially and temporally high-resolved absolute pressures on the turbine surface. Goal of the investigation is to identify critical operating conditions. Important is also to investigate the effect of a scroll connection valve on blade excitation. The investigations utilize validated tools that were introduced and successfully applied to several turbine types in a series of publications over recent years. It can be stated that the engine operating condition and the admission type significantly influence the forced response reaction of the blade to the different excitation orders (EO). In case of equal admission even (or multiples of two) EOs generate the largest dynamic blade stress as can be expected due to the two turbine inlet segments. This reaction also increases with the engine speed. In the case of unequal admission, the odd EOs produce the largest forced response reaction. The maximum dynamic blade stress occurs in the region where the scroll connection is just closed. Above all, the scroll connection valve influences the Beta value and thus the basic behavior — unequal or equal admission. It has been possible to reconstruct the forced response behavior of the turbine blade within an engine combustion cycle. For the first time it could be shown for a double scroll application that there is a significant dynamic blade stress change dependent on the engine crankshaft angle. Certainly, due to the inertia of the mass and damping (mass, structure, flow), the blade will not exactly follow the predicted course. However, it is clear that the transient processes within an engine combustion cycle will affect the dynamic blade stress. This applies to the turbine wheels investigated in the work at hand with low damping, high eigenfrequencies and the considered internal combustion engines — as they are typically used in the passenger car sector.

Effect of Mixing Quality on NOx Emissions in Reheat Combustion of GT24 and GT26 Engines

2011 ◽  
Author(s):  
K. Michael Du¨sing ◽  
Andrea Ciani ◽  
Adnan Eroglu
Keyword(s):  
High Pressure ◽  
Development Process ◽  
Flow Characteristic ◽  
Water Channel ◽  
Cost Effective ◽  
Nox Emissions ◽  
Combustion System ◽  
Low Pressure Turbine ◽  
Effective Development ◽  
System 1

Alstoms GT24 and GT26 engines feature a unique sequential combustion system [1, 2]. This system consists of a premixed combustor (called EV), which is followed by a high pressure turbine, a reheat combustor (called SEV) and a low pressure turbine (Figure 1). Recently improvements in NOx performance of the SEV have been demonstrated. Starting with relatively simple methods numerous design variants have been tested and down selected. Further down-selection has been done with methods of increased complexity. Overall a fast and cost effective development process has been assured. During the development process the variation coefficient and unmixedness measured and calculated for mixing only systems (CFD and water channel) has proven to be a reliable indicators for low NOx emissions for the real combustion system on atmospheric and high pressure test rigs. To demonstrate this a comparison of both quantities against NOx emissions is shown. The paper focuses on the NOx results achieved during this development and its relation to mixing quantities. Using this relation, together with a detailed understanding of the flow characteristic in the SEV burner, reductions in NOx emissions for GT24 and GT26 SEV burner and lance hardware can be reached using relatively simple methods.

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