Turbocharged Diesel Engine Modeling for Nonlinear Engine Control and State Estimation

1995 ◽  
Vol 117 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Minghui Kao ◽  
John J. Moskwa

Engine models that are used for nonlinear diesel engine control, state estimation, and model-based diagnostics are presented in this paper. By collecting, modifying, and adding to current available engine modeling techniques, two diesel engine models, a mean torque production model and a cylinder-by-cylinder model, are summarized for use in the formulation of control and state observation algorithms. In the cylinder-by-cylinder model, a time-varying crankshaft inertia model is added to a cylinder pressure generator to simulate engine speed variations due to discrete combustion events. Fuel injection timing and duration are control inputs while varying engine speed, cylinder pressure, and indicated torque are outputs from simulation. These diesel engine models can be used as engine simulators and to design diesel engine controllers and observers.

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.


Author(s):  
Enrico Corti ◽  
Davide Moro

In recent years engine control development focused the attention on torque-based models, that allow improving driveability and implementing traction control strategies. The design of such a torque-based engine control strategy requires the knowledge of the torque produce by the engine, which depends on fuel injection time, spark advance, throttle opening, EGR command, … In the actual engine control strategies this is mainly done by means of static maps stored in the ECU memory. The real engine torque production under every operating condition can be evaluated by means of the in-cylinder pressure estimation, thus allowing a torque based closed loop control strategy. Many approaches are present in the literature showing the possibility of on-board estimating the actual torque produced by the engine not simply by using static maps, but estimating it through other measured signals. Most of the methodologies that do not require a specific sensor placed on the engine are based either on the engine speed fluctuations (measured by a pick-up facing the flywheel teeth) or on the engine block vibrations (measured by the knock sensor), performing better for engines with a low number of cylinders. The paper presents an original methodology based on the instantaneous engine speed fluctuations, that has been usefully applied to engines with higher number of cylinders. The methodology is based on the observation of the speed fluctuations in a crankshaft window inside the expansion stroke and on the hypothesis that there exists a strong correlation between these engine speed fluctuations and pressure inside the selected cylinder. This relationship has been characterized using Frequency Response Functions (FRF) for each steady-state engine operating condition. In the following the FRFs have been used to perform in-cylinder pressure and then indicated torque estimation under every operating condition, and a specific signal processing algorithm has been developed in order to apply the procedure during speed and load engine transients. The experimental tests have been conducted mounting a six-cylinder turbo-charged spark-ignited engine in a test cell. The application on-board a vehicle of the same methodology seems to be feasible due to the quickness of the algorithm employed and the presence on-board of all the sensors required for the implementation.


2019 ◽  
pp. 146808741987854
Author(s):  
Hossein Ahmadian ◽  
Gholamhassan Najafi ◽  
Barat Ghobadian ◽  
Seyed Reza Hassan-Beygi ◽  
Seyed Salar Hoseini

The understanding of noise generation and source identification is vital in noise control. This research was conducted to experimentally evaluate combustion-induced noise and vibration using coherence and wavelet coherence estimates. A single-cylinder direct-injection diesel engine was chosen for experimental investigation. The independent variables for conducting experiments were injection timing with five levels of 22, 27, 32 (normal), 37, and 42 crank angles before the top dead center, and also the engine torque load with four levels of 55%, 70%, 85%, and 100% of the rated value. The signals of cylinder pressure, liner acceleration, and radiated sound pressure of the test engine were measured and recorded. Then, coherency and wavelet coherency experiments were carried out between cylinder pressure and liner acceleration, cylinder pressure and sound pressure, and liner acceleration and sound pressure signals in MATLAB software. The results indicated that increasing load would increase wavelet coherency between cylinder pressure and liner acceleration signals at frequencies higher than 1 kHz. The coherent regions between cylinder pressure and sound pressure signals were mainly at frequencies higher than 1 kHz while advancing the fuel injection timing had shifted the coherency toward lower frequencies. In general, with advancing injection timing, the coherent regions between liner acceleration and sound pressure signals have appeared at broader time ranges, especially at frequencies between 100 and 500 Hz. Comparing the results of the wavelet coherency and coherency tests, we concluded that wavelet coherency is a more accurate and descriptive tool in evaluating the combustion-induced noise and vibration.


2021 ◽  
Vol 302 ◽  
pp. 01004
Author(s):  
Theeranan Phatai ◽  
Raschanon Kumpiranon ◽  
Kritsana Ounnarut ◽  
Nattapol Pongrasri ◽  
Pubet Meenaroch ◽  
...  

The purpose of this study is to investigate injection timing affected particle size distribution of a diesel engine fueled with biodiesel/diesel blends. The biodiesel blending ratios include 7, 10 and 20%vol. The experiments were operated at engine speed 1,500 rpm under 25, 50 and 75% engine loads and two different injection timing (25.5 CAD BTDC and 27.5 CAD BTDC). The effects of biodiesel addition and injection timing on the changes in black smoke and particle size distribution were discussed. Results showed that the standard injection timing for the addition of biodiesel, especially for 20% biodiesel blended with diesel fuel (B20) had a significant effect of increasing particle concentration and thus black smoke emission. The advanced injection timing for B20 could improve combustion efficiency and reduce small particles emission in nucleation-mode (Dp 5 – 50 nm) and particles in accumulation-mode (Dp 50 – 1,000 nm) became the smaller particle size, compared to standard and retarded injection timing. Moreover, the oxygen content in biodiesel could improve combustion efficiency and reduce the emission but it is necessary to modify the engine especially fuel injection timing.


2020 ◽  
pp. 202-202
Author(s):  
Jie Ruan ◽  
Helin Xiao ◽  
Xiaolong Yang ◽  
Fengyun Guo ◽  
Jiaqi Huang ◽  
...  

Currently, biodiesel has been received much attention from many researchers around the world due to its clean and renewable characteristics. In the present study, combustion and emissions characteristics have been studied on a modified four-cylinder, 4-stroke, water-cooled, DICI engine equipped with a common rail fuel injection system fueled with methanol-biodiesel blends as well as pure biodiesel. The experiment was operated at a constant engine speed of 1800 rpm and injection timing from 2.5 to 22.5?CA BTDC. With the injection timing advanced peak in-cylinder pressure and maximum HRR(heat release rate)increased while combustion start points were advanced. Ignition delay was shorten first and then prolonged while BTE(brake thermal efficiency)was increased first and then decreased. With the injection timing in advance, NOX emissions increased, 1,3-butadiene and benzene emissions decreased while HC and acetaldehyde emissions decreased first and then increased, and soot emissions increased first and then decreased.


1975 ◽  
Vol 97 (4) ◽  
pp. 1227-1233 ◽  
Author(s):  
A. F. Seybert ◽  
M. J. Crocker

A technique is presented in which the effects on noise of changing diesel engine operating parameters can be predicted. Traditionally, the effects have been determined by experiment. The technique presented in this paper utilizes experimentally determined frequency response functions between each cylinder pressure input and the engine noise. Once the frequency responses are measured, the engine noise can be calculated for an arbitrary cylinder pressure input. The effect of injection timing, engine load, and engine speed are predicted using cylinder pressure histories obtained from a single cylinder research engine. Experimental results are presented, showing good agreement with predicted data. It has been found that the measured frequency responses are independent of the cylinder pressure level. Also presented here is the multiple coherence between the cylinder pressures and the engine noise and the ordinary coherence between two typical cylinder pressures.


Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).


Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.


2012 ◽  
Vol 614-615 ◽  
pp. 337-342
Author(s):  
Li Luo ◽  
Bin Xu ◽  
Zhi Hao Ma ◽  
Jian Wu ◽  
Ming Li

In this study, the effect of injection timing on combustion characteristics of a direct injection, electronically controlled, high pressure, common rail, turbocharged and intercooled engine fuelled with different pistacia chinensis bunge seed biodiesel/diesel blends has been experimentally investigated. The results indicated that brake specific fuel consumption reduces with the increasing of fuel injection advance angle and enhances with the increasing of biodiesel content in the blends. The peak of cylinder pressure and maximum combustion temperature increase evidently with the increment of fuel injection advance angle. However, the combustion of biodiesel blends starts earlier than diesel at the same fuel injection advance angle. At both conditions, the combustion duration and the peak of heat release rate are insensitive to the changing of injection timing.


2015 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
D.N. Basavarajappa ◽  
N. R. Banapurmath ◽  
S.V. Khandal ◽  
G. Manavendra

For economic and social development of any country energy is one of the most essential requirements. Continuously increasing price of crude petroleum fuels in the present days coupled with alarming emissions and stringent emission regulations has led to growing attention towards use of alternative fuels like vegetable oils, alcoholic and gaseous fuels for diesel engine applications. Use of such fuels can ease the burden on the economy by curtailing the fuel imports. Diesel engines are highly efficient and the main problems associated with them is their high smoke and NOx emissions.  Hence there is an urgent need to promote the use of alternative fuels in place of high speed diesel (HSD) as substitute. India has a large agriculture base that can be used as a feed stock to obtain newer fuel which is renewable and sustainable. Accordingly Uppage oil methyl ester (UOME) biodiesel was selected as an alternative fuel. Use of biodiesels in diesel engines fitted with mechanical fuel injection systems has limitation on the injector opening pressure (300 bar). CRDI system can overcome this drawback by injecting fuel at very high pressures (1500-2500 bar) and is most suitable for biodiesel fuels which are high viscous. This paper presents the performance and emission characteristics of a CRDI diesel engine fuelled with UOME biodiesel at different injection timings and injection pressures. From the experimental evidence it was revealed that UOME biodiesel yielded overall better performance with reduced emissions at retarded injection timing of -10° BTDC in CRDI mode of engine operation.


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