The Problem of Predicting Rate of Heat Release in Diesel Engines

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.

Download Full-text

Quasi-Dimensional Diesel Engine Combustion Modeling With Improved Diesel Spray Tip Penetration, Ignition Delay, and Heat Release Submodels

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4036575 ◽

2017 ◽

Vol 139 (11) ◽

Cited By ~ 2

Author(s):

Shuonan Xu ◽

Hirotaka Yamakawa ◽

Keiya Nishida ◽

Zoran Filipi

Keyword(s):

Diesel Engine ◽

Heat Release ◽

Diesel Engines ◽

Ignition Delay ◽

Air Entrainment ◽

Oxygen Mixture ◽

Diesel Spray ◽

Spray Tip Penetration ◽

Simulation Tools ◽

The Impact

Increasingly stringent fuel economy and CO2 emission regulations provide a strong impetus for development of high-efficiency engine technologies. Diesel engines dominate the heavy duty market and significant segments of the global light duty market due to their intrinsically higher thermal efficiency compared to spark-ignited (SI) engine counterparts. Predictive simulation tools can significantly reduce the time and cost associated with optimization of engine injection strategies, and enable investigation over a broad operating space unconstrained by availability of prototype hardware. In comparison with 0D/1D and 3D simulations, Quasi-Dimensional (quasi-D) models offer a balance between predictiveness and computational effort, thus making them very suitable for enhancing the fidelity of engine system simulation tools. A most widely used approach for diesel engine applications is a multizone spray and combustion model pioneered by Hiroyasu and his group. It divides diesel spray into packets and tracks fuel evaporation, air entrainment, gas properties, and ignition delay (induction time) individually during the injection and combustion event. However, original submodels are not well suited for modern diesel engines, and the main objective of this work is to develop a multizonal simulation capable of capturing the impact of high-injection pressures and exhaust gas recirculation (EGR). In particular, a new spray tip penetration submodel is developed based on measurements obtained in a high-pressure, high-temperature constant volume combustion vessel for pressures as high as 1450 bar. Next, ignition delay correlation is modified to capture the effect of reduced oxygen concentration in engines with EGR, and an algorithm considering the chemical reaction rate of hydrocarbon–oxygen mixture improves prediction of the heat release rates. Spray and combustion predictions were validated with experiments on a single-cylinder diesel engine with common rail fuel injection, charge boosting, and EGR.

Download Full-text

Quasi-D Diesel Engine Combustion Modeling With Improved Diesel Spray Tip Penetration, Ignition Delay and Heat Release Sub-Models

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9403 ◽

2016 ◽

Author(s):

Shuonan Xu ◽

Hirotaka Yamakawa ◽

Keiya Nishida ◽

Zoran Filipi

Keyword(s):

Diesel Engine ◽

Heat Release ◽

Diesel Engines ◽

Ignition Delay ◽

Air Entrainment ◽

Oxygen Mixture ◽

Diesel Spray ◽

Spray Tip Penetration ◽

Simulation Tools ◽

The Impact

Increasingly stringent fuel economy and CO2 emission regulations provide a strong impetus for development of high efficiency engine technologies. Diesel engines dominate the heavy duty market and significant segments of the global light duty market due to their intrinsically higher thermal efficiency compared to spark ignited (SI) engine counterparts. Predictive simulation tools can significantly reduce the time and cost associated with optimization of engine injection strategies, and enable investigation over a broad operating space unconstrained by availability of prototype hardware. In comparison with 0-D/1-D and 3-D simulations, Quasi-D models offer a balance between predictiveness and computational effort, thus making them very suitable for enhancing the fidelity of engine system simulation tools. A most widely used approach for diesel engine applications is a multi-zone spray and combustion model pioneered by Hiroyasu and his group. It divides diesel spray into packets and tracks fuel evaporation, air entrainment, gas properties and ignition delay (induction time) individually during the injection and combustion event. However, original sub-models are not well suited for modern diesel engines, and the main objective of this work is to develop a multi-zonal simulation capable of capturing the impact of high-injection pressures and Exhaust Gas Recirculation (EGR). In particular, a new spray tip penetration sub-model is developed based on measurements obtained in a high-pressure, high-temperature constant volume combustion vessel for pressures as high as 1450 bar. Next, ignition delay correlation is modified to capture the effect of reduced oxygen concentration in engines with EGR, and an algorithm considering the chemical reaction rate of hydrocarbon-oxygen mixture improves prediction of the heat release rates. Spray and combustion predictions were validated with experiments on a single-cylinder diesel engine with common rail fuel injection, charge boosting, and EGR.

Download Full-text

PRESUMPTIONS OF EFFECTIVE OPERATION OF DIESEL ENGINES RUNNING ON RME BIODIESEL. RESEARCH ON KINETICS OF COMBUSTION OF RME BIODIESEL

Transport ◽

10.3846/16484142.2007.9638112 ◽

2007 ◽

Vol 22 (2) ◽

pp. 126-133 ◽

Cited By ~ 15

Author(s):

Sergejus Lebedevas ◽

Andrius Vaicekauskas ◽

Pavel Suškov

Keyword(s):

Diesel Engine ◽

Heat Release ◽

Diesel Engines ◽

Fuel Injection ◽

Injection Pressure ◽

Cylinder Pressure ◽

Induction Heat ◽

Effective Operation ◽

Fuel Injection Pressure ◽

Kinetics Of

The results of experimental research on kinetics of fuel combustion of diesel engine A41are presented in the publication. The change of characteristics of indicated work (in‐cylinder pressure and temperature, period of induction, heat release and heat release rate) and fuel injection (fuel injection pressure, fuel injection phases) was determined in diesel engine running on RME biodiesel being compared to diesel fuel. The results of researches were used to explain experimentally determined changes of operational and ecological characteristics of diesel engine running on RME biodiesel. In addition, the reliability of diesel engine A41 running on RME biodiesel was evaluated. The presumptions of effective operation of diesel engines running on RME biodiesel were formulated.

Download Full-text

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

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4036101 ◽

2017 ◽

Vol 139 (9) ◽

Cited By ~ 3

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.

Download Full-text

Closed Loop Control for Common Rail Diesel Engines based on Rate of Heat Release

Advances in Soft Computing - Applied Soft Computing Technologies: The Challenge of Complexity ◽

10.1007/3-540-31662-0_43 ◽

2006 ◽

pp. 559-568

Author(s):

Nicola Cesario

Keyword(s):

Heat Release ◽

Diesel Engines ◽

Closed Loop ◽

Common Rail ◽

Closed Loop Control ◽

Loop Control ◽

Rate Of Heat Release

Download Full-text

Experimental study of multiple pilot injection strategy in an automotive direct injection diesel engine

MATEC Web of Conferences ◽

10.1051/matecconf/201823403007 ◽

2018 ◽

Vol 234 ◽

pp. 03007

Author(s):

Plamen Punov ◽

Tsvetomir Gechev ◽

Svetoslav Mihalkov ◽

Pierre Podevin ◽

Dalibor Barta

Keyword(s):

Experimental Study ◽

Diesel Engine ◽

Diesel Engines ◽

Direct Injection ◽

Combustion Process ◽

Injection Timing ◽

Pilot Injection ◽

Injection Strategy ◽

Direct Injection Diesel Engine ◽

Rate Of Heat Release

The pilot injection strategy is a widely used approach for reducing the noise of the combustion process in direct injection diesel engines. In the last generation of automotive diesel engines up to several pilot injections could occur to better control the rate of heat release (ROHR) in the cylinder as well as the pollutant formation. However, determination of the timing and duration for each pilot injection needs to be precisely optimised. In this paper an experimental study of the pilot injection strategy was conducted on a direct injection diesel engine. Single and double pilot injection strategy was studied. The engine rated power is 100 kW at 4000 rpm while the rated torque is 320 Nm at 2000 rpm. An engine operating point determined by the rotation speed of 1400 rpm and torque of 100 Nm was chosen. The pilot and pre-injection timing was widely varied in order to study the influence on the combustion process as well as on the fuel consumption.

Download Full-text