Experimental Investigation and Mathematical Presentation of Rate of Heat Release in Diesel Engines Dependent upon Engine Operating Conditions

1974 ◽  
Author(s):  
G. Woschni ◽  
F. Anisits
Keyword(s):  
Experimental Investigation ◽  
Heat Release ◽  
Diesel Engines ◽  
Operating Conditions ◽  
Rate Of Heat Release ◽  
Mathematical Presentation

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
Peter G. Dowell ◽  
Sam Akehurst ◽  
Richard D. Burke
Keyword(s):  
Heat Release ◽  
Diesel Engines ◽  
Engine Speed ◽  
Fuel Injection ◽  
Maximum Pressure ◽  
Injection Model ◽  
Wall Impingement ◽  
Small Set ◽  
Rate Of Heat Release ◽  
Engine System

To meet the increasingly stringent emissions standards, diesel engines need to include more active technologies with their associated control systems. Hardware-in-the-loop (HiL) approaches are becoming popular where the engine system is represented as a real-time capable model to allow development of the controller hardware and software without the need for the real engine system. This paper focusses on the engine model required in such approaches. A number of semi-physical, zero-dimensional combustion modeling techniques are enhanced and combined into a complete model, these include—ignition delay, premixed and diffusion combustion and wall impingement. In addition, a fuel injection model was used to provide fuel injection rate from solenoid energizing signals. The model was parameterized using a small set of experimental data from an engine dynamometer test facility and validated against a complete data set covering the full engine speed and torque range. The model was shown to characterize the rate of heat release (RoHR) well over the engine speed and load range. Critically, the wall impingement model improved R2 value for maximum RoHR from 0.89 to 0.96. This was reflected in the model's ability to match both pilot and main combustion phasing, and peak heat release rates derived from measured data. The model predicted indicated mean effective pressure and maximum pressure with R2 values of 0.99 across the engine map. The worst prediction was for the angle of maximum pressure which had an R2 of 0.74. The results demonstrate the predictive ability of the model, with only a small set of empirical data for training—this is a key advantage over conventional methods. The fuel injection model yielded good results for predicted injection quantity (R2 = 0.99) and enabled the use of the RoHR model without the need for measured rate of injection.

Bayesian estimate of pre-mixed and diffusive rate of heat release phases in marine diesel engines

2016 ◽  
Vol 39 (5) ◽  
pp. 1835-1844 ◽  
Author(s):  
Marcelo A. Pasqualette ◽  
Diego C. Estumano ◽  
Fabiana C. Hamilton ◽  
Marcelo J. Colaço ◽  
Albino J. K. Leiroz ◽  
...  
Keyword(s):  
Heat Release ◽  
Diesel Engines ◽  
Bayesian Estimate ◽  
Marine Diesel ◽  
Rate Of Heat Release

Zero Dimensional Quasi-Predictive Thermodynamic Simulation for Establishing Initial Cylinder Conditions for CFD Simulation of Diesel Combustion

2015 ◽  
Author(s):  
Ryan A. Bandura ◽  
Timothy J. Jacobs
Keyword(s):  
Experimental Data ◽  
Heat Release ◽  
Cfd Simulation ◽  
Fuel Injection ◽  
Initial Conditions ◽  
Thermodynamic Simulation ◽  
Operating Conditions ◽  
Gas Composition ◽  
Gas Temperature ◽  
Rate Of Heat Release

Computational fluid dynamics (CFD) is now a ubiquitous computational tool for engine design and diagnosis. It is often necessary to provide well-known initial cycle conditions to commence the CFD computations. Such initial conditions can be provided by experimental data. To create an opportunity to computationally study engine conditions where experimental data are not available, a zero-dimensional quasi-predictive thermodynamic simulation is developed that uses well-established spray model to predict rate of heat release and calculated burned gas composition and temperature to predict nitric oxide (NO) concentration. This simulation could in turn be used in reverse to solve for initial cylinder conditions for a targeted NO concentration. This paper details the thermodynamic simulation for diesel engine operating conditions. The goal is to produce a code that is capable of predicting NO emissions as well as performance characteristics such as mean effective pressure (MEP) and brake specific fuel consumption (BSFC). The simulation uses general conservation of mass and energy approaches to model intake, compression, and exhaust. Rate of heat release prediction is based on an existing spray model to predict how fuel concentrations within the spray jet change with penetration. Rate of heat release provides predicted cylinder pressure, which is then validated against experimental pressure data under known operating conditions. An equilibrium mechanism is used to determine burned gas composition which, along with burned gas temperature, can be used for prediction of NO in the cylinder. NO is predicted using the extended Zeldovich mechanism. This mechanism is highly sensitive to temperature, and it is therefore important to accurately predict cylinder gas temperature to obtain correct NO values. Additionally, MEP and BSFC are determined. The simulation focuses on single fuel injection events, but insights are provided to expand the simulation to model multiple injection events.

scholarly journals Study of the influence of compression ratio on the rate of heat release in small displacement Diesel engines

2018 ◽  
Vol 11 (21) ◽  
pp. 1-8
Author(s):  
Jorge Duarte Forero ◽  
Guillermo E. Valencia ◽  
Luis G. Obregon ◽  
◽  
◽  
...  
Keyword(s):  
Heat Release ◽  
Compression Ratio ◽  
Diesel Engines ◽  
Small Displacement ◽  
Rate Of Heat Release

The Problem of Predicting Rate of Heat Release in Diesel Engines

1969 ◽  
Vol 184 (10) ◽  
pp. 192-202 ◽  
Author(s):  
H. C. Grigg ◽  
M. H. Syed
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Chemical Kinetics ◽  
Diesel Engines ◽  
Turbulent Mixing ◽  
Air Entrainment ◽  
Experimental Results ◽  
Fuel Sprays ◽  
Rate Of Heat Release ◽  
Kinetics Of

Two simple models for the rate of heat release in diesel engines are described. The factors taken into account in the models are rate of entrainment of air into the fuel sprays, the rate of turbulent mixing of fuel and air within the spray, and the chemical kinetics of burning. The models differ in their treatment of the rate of air entrainment. Comparisons are made with experimental results for a diesel engine running at two speeds and a variety of turbocharging ratios. The overall agreement with experiment in respect of shape of rate of heat release diagram is good, with the exception of the naturally aspirated cases where the rate of air entrainment is too low.

Accurate prediction of the rate of heat release in a modern direct injection diesel engine

2002 ◽  
Vol 216 (8) ◽  
pp. 663-675 ◽  
Author(s):  
P A Lakshminarayanan ◽  
Y V Aghav ◽  
A D Dani ◽  
P S Mehta
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Direct Injection ◽  
Turbulent Energy ◽  
Operating Conditions ◽  
Combustion Model ◽  
Injection Velocity ◽  
Mixing Rate ◽  
Di Diesel Engine ◽  
Rate Of Heat Release

An accurate model for the heat release rate in a modern direct injection (DI) diesel engine is newly evolved from the known mixing controlled combustion model. The combustion rate could be precisely described by relating the mixing rate to the turbulent energy created at the exit of the nozzle as a function of the injection velocity and by considering the dissipation of energy in free air and along the wall. The complete absence of tuning constants distinguishes the model from the other zero-dimensional or pseudomultidimensional models, at the same time retaining the simplicity. Successful prediction of the history of heat release in engines widely varying in bores, rated speeds and types of aspirations, at all operating conditions, validated the model.

Rate of Heat Release in High-Speed Indirect Injection Diesel Engines

1969 ◽  
Vol 184 (10) ◽  
pp. 122-129 ◽  
Author(s):  
C. M. Bowden ◽  
B. S. Samaga ◽  
W-T. Lyn
Keyword(s):  
Heat Release ◽  
Diesel Engines ◽  
High Speed ◽  
Empirical Scheme ◽  
Rate Of Heat Release ◽  
Semi Empirical ◽  
The Relationship

The rates of injection and heat release of two designs of indirect-injection diesel engines have been studied over a range of speed, load, and timing. The relationship between these two quantities is significantly different from that previously found for open-chamber engines. It is suggested that only part of the air is available for mixing in a divided-chamber engine, and the movement of the piston controls to some extent the availability of the remaining part of the air. A semi-empirical scheme is proposed for relating the rate of injection to the rate of heat release for this type of engine.

Fuel-Forced Flame Response of a Lean-Premixed Combustor

2011 ◽  
Author(s):  
Poravee Orawannukul ◽  
Jong Guen Lee ◽  
Bryan D. Quay ◽  
Domenic A. Santavicca
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Operating Conditions ◽  
Chemiluminescence Intensity ◽  
Combustion Dynamics ◽  
Lean Premixed ◽  
Flame Response ◽  
Rate Of Heat Release ◽  
The Relationship

The response of a swirl-stabilized flame to equivalence ratio fluctuations is experimentally investigated in a single-nozzle lean premixed combustor. Equivalence ratio fluctuations are produced using a siren device to modulate the flow rate of fuel to the injector, while the air flow rate is kept constant. The magnitude and phase of the equivalence ratio fluctuations are measured near the exit of the nozzle using an infrared absorption technique. The flame response is characterized by the fluctuation in the flame’s overall rate of heat release, which is determined from the total CH* chemiluminescence emission from the flame. The relationship between total CH* chemiluminescence intensity and the flame’s overall rate of heat release is determined from a separate calibration experiment which accounts for the nonlinear relationship between chemiluminescence intensity and equivalence ratio. Measurements of the normalized equivalence ratio fluctuation and the normalized rate of heat release fluctuation are made over a range of modulation frequencies from 200 Hz to 440 Hz, which corresponds to Strouhal numbers from 0.4 to 2.8. These measurements are used to determine the fuel-forced flame transfer function which expresses the relationship between the equivalence ratio and rate of heat release fluctuations in terms of a gain and phase as a function of frequency. In addition, phase-synchronized CH* chemiluminescence images are captured to study the dynamics of the flame response over the modulation period. These measurements are made over a range of operating conditions and the results are analyzed to identify and better understand the mechanisms whereby equivalence ratio fluctuations result in fluctuations in the flame’s overall rate of heat release. Such information is essential to guide the formulation and validation of analytical fuel-forced flame response models and hence to predict combustion dynamics in gas turbine combustors.

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