Diesel Engine Control Research Articles

Research on Fuel Offset Control of High-Pressure Common-Rail Diesel Engine Based on Crankshaft Segment Signals.

This paper studies the fuel supply offset of diesel engines based on the crankshaft segment signal. Engine nonuniformity refers to the crankshaft torque fluctuation caused by cylinder-to-cylinder differences caused by misfiring or differences in the fuel supply or air supply. Fuel injection offset can reduce the nonuniformity between cylinders to realize high-efficiency and low pollution combustion. Based on crankshaft segment signal characteristics, an individual cylinder fuel offset control (FOC) strategy was built. The high-pressure common-rail diesel engine operating nonuniform control strategy was put forward. Based on crankshaft segment signal characteristics at different operating conditions, the reasonable operating condition of detecting the engine individual cylinder nonuniform degree was put forward. The open-loop and closed-loop control mode based on the condition was set up. The proportional-integral (PI) control algorithm is proposed to quantify engine individual cylinder nonuniform degree, and the fuel amount offset value was obtained. According to the principle of FOC, based on the automotive electronics development ASCET software platform, the FOC strategy module of the electronic control unit (ECU) was designed, and the simulation experiment was carried out. Research shows that for Z cylinder engine, just the first Z/2 harmonic components below fire frequency can fully reflect the state of the engine’s nonuniform operation. The control target to individual cylinder FOC is zero for the synthetic waveform amplitude of the first Z/2 harmonic components. Compared with the traditional quantization method, the fuel offset information extracted from the crankshaft segment signal has stronger anti-interference and more accurate parameters. FOC algorithm can accurately reflect the engine’s operating nonuniformity. The control of the nonuniformity is reasonable. The offset fuel amount calculated by FOC is very consistent with the fuel supply state of each cylinder set by the experiment, which meets the requirement of accurate fuel injection control of the diesel engine.

Neural network-based air handling control for modern diesel engines

Complex air handling systems, featuring technologies such as exhaust gas recirculation (EGR) and variable geometry turbochargers (VGTs), are commonly used in modern diesel engines to meet stringent emissions and fuel economy requirements. The control of diesel air handling systems with EGR and VGTs is challenging because of their nonlinearity and coupled dynamics. In this paper, artificial neural networks (ANNs) and recurrent neural networks (RNNs) are applied to control the low pressure (LP) EGR valve position and VGT vane position simultaneously on a light-duty multi-cylinder diesel engine. Intake manifold pressure (IMP) and air-fuel equivalence ratio, or [Formula: see text], are selected as the control objectives since they directly impact engine emissions and cylinder power output. Meanwhile both signals are available on production engines, so no additional hardware costs for measurement systems will be introduced. Both transient and steady state experimental data are separately used to train the two categories of neural networks (NNs). The NNs with minimum mean square error (MSE) for the training data sets are compared to conventional proportional-integral (PI) control and model predictive control (MPC). The most accurate NN controller has almost no overshoot during the transient process while the steady state error [Formula: see text] and IMP are at most 7.0% and 3.8%, respectively, under a wide range of engine speeds from 2500 to 4000 rpm, thus showing the potential of this approach.

Indicated efficiency optimization by in-cycle closed-loop combustion control of diesel engines

This paper revises the design process for closed-loop combustion control based on in-cycle feedback. Methods for the necessary observers, detectors and virtual sensors are also discussed. The control problem tackles the indicated efficiency optimization, following two approaches, direct and indirect optimization. The argumentation provides a comprehensive overview on how to specify and integrate different methods available at the literature. The results presented are based on previous experimental and simulation work on a Scania D13 engine by the authors. A pilot and main injection scheme is used to increase the degrees of freedom and achieve a higher nominal indicated efficiency. An in-cycle controllability study indicated that the pilot mass is the most significant parameter to monitor for the in-cycle disturbance rejection. Based on the heat release analysis, feedback is obtained from the pilot mass estimation, with a real-time accuracy of ±0.5 mg/st. Still, to overcome the inherent delay between feedback and control action, predictive models are necessary. The required accuracy can be obtained by the multi-cylinder adaptation of the model parameters. The paper presents two approaches for the design of in-cycle controllers to improve the indicated efficiency under hardware and emission constraints. In the direct efficiency optimization, a model predicts the indicated efficiency change from the in-cycle pilot estimations to optimize the main fuel injection. Compared to in-cycle open-loop operation, the in-cycle controller increases the indicated efficiency by +0.42%unit. In the indirect efficiency optimization, the controller is designed to reduced the cyclic dispersion of the pilot SOC (down to ±0.4CAD), the pilot burnt mass (down to ±0.6 mg), the main SOC (down to ±0.3CAD) and the IMEP (down to ±0.2 bar). In case pilot misfire is detected, the CA50 shift of +2.6CAD is compensated and reduced to +0.5CAD. The indicated efficiency is maximized by the set-point optimization in a Monte Carlo simulation of a stochastic combustion model that captures the reduced cyclic dispersion of the controller. This approach increased the indicated efficiency by +0.6%unit under constraints on the maximum pressure, the maximum pressure rise rate, the maximum and the minimum exhaust temperature.Despite the controller effectiveness was quantified experimentally, the simulation results must be validated experimentally as well. Further investigations can focus on including constraints on emissions, how to handle the constraints on-line, the inclusion of additional injection pulses in the optimization, as well as variable valve timing actuation or injection of emissions reductants.

Calculation of Intake Oxygen Concentration through Intake CO2 Measurement and Evaluation of Its Effect on Nitrogen Oxide Prediction Accuracy in a Heavy-Duty Diesel Engine

A new procedure, based on measurement of intake CO2 concentration and ambient humidity was developed and assessed in this study for different diesel engines in order to evaluate the oxygen concentration in the intake manifold. Steady-state and transient datasets were used for this purpose. The method is very fast to implement since it does not require any tuning procedure and it involves just one engine-related input quantity. Moreover, its accuracy is very high since it was found that the absolute error between the measured and predicted intake O2 levels is in the ±0.15% range. The method was applied to verify the performance of a previously developed NOx model under transient operating conditions. This model had previously been adopted by the authors during the IMPERIUM H2020 EU project to set up a model-based controller for a heavy-duty diesel engine. The performance of the NOx model was evaluated considering two cases in which the intake O2 concentration is either derived from engine-control unit sub-models or from the newly developed method. It was found that a significant improvement in NOx model accuracy is obtained in the latter case, and this allowed the previously developed NOx model to be further validated under transient operating conditions.

Hybrid Physics-Based Neural Network Models for Diesel Combustion Phasing Prediction

Conventional control-oriented physics-based models can be leveraged for combustion phasing control in modern diesel engines, but very accurate models often require significant computational power. On the other hand, Artificial Neural Network (ANN) models can have high predictive capabilities and lower computational costs but their heuristic nature may make them less desirable for complex and impactful parameters like combustion phasing. This paper addresses these issues by leveraging the advantages of both modeling methodologies in an integrated modeling framework which can be utilized for real-time combustion control for a modern diesel engine. The models are validated with data from a 2.0 L turbocharged diesel engine which is fitted with dual loop exhaust gas recirculation. The results of the modeling frameworks are compared and show that the proposed hybrid model framework can have a Pearson Product-Correlation Coefficient (PPMCC) of a 100% and an RMSE of 8.79 × 10-8 CAD; as compared to the physics-based model with a PPMCC of a 95% and an RMSE of 0.17 CAD.

Benefits of Feedforward for Model Predictive Airpath Control of Diesel Engines

This paper investigates options to complement a diesel engine airpath feedback controller with a feedforward. The control objective is to track the intake manifold pressure and exhaust gas recirculation (EGR) rate targets by manipulating the EGR valve and variable geometry turbine (VGT) while satisfying state and input constraints. The feedback controller is based on rate-based Model Predictive Control (MPC) that provides integral action for tracking. Two options for the feedforward are considered one based on a look-up table that specifies the feedforward as a function of engine speed and fuel injection rate, and another one based on a (non-rate-based) MPC that generates dynamic feedforward trajectories. The controllers are designed and verified using a high-fidelity engine model in GT-Power and exploit a low-order rate-based linear parameter-varying (LPV) model for prediction which is identified from transient response data generated by the GT-Power model. It is shown that the combination of feedforward and feedback MPC has the potential to improve the performance and robustness of the control design. In particular, the feedback MPC without feedforward can lose stability at low engine speeds, while MPC-based feedforward results in the best transient response. Mechanisms by which feedforward is able to assist in stabilization and improve performance are discussed.

Is it possible to turn a diesel engine into a less pollutant device?

The current tendency in the eastern part of Europe is to modify old diesel engines with the purpose of improving characteristics in terms of horsepower and torque, but also to reduce the generated pollution. The diesel engines are still in use, against to the tendencies of renouncing to their support, at least in larger urban & industrial areas, where the pollution level, especially the particulate matter (particles PM10, PM2.5) and ozone concentrations, also the NOx are supposed to be generated mostly by diesel engine vehicles. The paper presents results concerning the influence of modifying the diesel engine control unit’s parameters, such as injection quantity, start of injection, intake air pressure and all the others correlated for better performance. The article brings into attention possibilities to reduce the exhaust pollution concentrations, correlated by simultaneous ways of improving the external characteristics of the engine by modifying the engine control unit’s parameters. Measurement results of a compression ignited internal combustion engine before and after the retrofitting, by reparametrization, meaning changing the parameters are presented and discussed.

ИССЛЕДОВАНИЕ РАБОТОСПОСОБНОСТИ ФОРСУНОК ТРАКТОРНЫХ ДИЗЕЛЕЙ

Fuel equipment is one of the main systems of tractor diesel engines, the technical condition of which determines such power and economic indicators as reliability and stability of operation. At the present stage, the vast majority of tractors in operation have a power reduced by about 10... 15% and fuel consumption increased by more than 15%, which is explained by such reasons as imperfection of methods and means of maintenance, the "age" of machines. It is known that up to half of the failures of tractor diesels are accounted for by fuel equipment, while a decrease in power has a negative impact on the performance of machine-tractor units. In addition, as a result of downtime and fuel overspending, agricultural producers incur significant losses. At the same time, the level of technical operation often remains very low, the frequency of maintenance is not observed, high-quality regulation of agricultural machines is not provided. Energy-saturated tractors with forced diesels are more demanding on the stability of adjustments. One of the ways to improve the efficiency of the existing tractor fleet is to improve the design of the sprayer. In this regard, this article presents the results of experimental studies devoted to evaluating the effectiveness of the design solution and determining the predicted operating time of sprayers of experimental and serial injectors installed on diesel engines SMD-62. Experienced sprayers have a reverse taper, which allows you to improve the mobility of the needle and self-adjust when assembling the nozzle. Analytical dependences of technical and economic indicators of the control diesel engine with experimental and serial sprayers depending on operational operating time are obtained. It is established that the maximum predicted operating time of experimental and serial sprayers is, respectively, 4130 and 39920 motor-hours. The results of the research showed that the operating time of experimental sprayers was higher by 1000 moto-hours than serial sprayers, and the probability of trouble–free operation was 2 times greater.

Determination of optimal control of a vessel diesel engine during non-stationary traffic regimes

The high pressure fuel system is the fundamental system that forms the indicator of the minimum fuel consumption per unit of the vessel's path. The calculation of the optimal control of the vessel complex with the main diesel engine is performed according to the criterion of the minimum fuel consumption per unit path at a given average velocity of the vessel. The propulsion of a vessel with a main diesel engine is described by equations. The equations contain a significant number of parameters, the reduction of which is performed by introducing dimensionless quantities, followed by bringing the equations into dimensionless forms. This made it possible to present a solution to the optimal control law for the main vessel diesel engine as part of the vessel complex. Optimal control of the vessel complex under stormy navigation conditions has been investigated. The calculations of the control law of the vessel complex, which ensure the movement of the vessel with the maximum average velocity in conditions of stormy navigation, are presented. It is determined that the established law of control of the vessel complex ensures the minimum fuel consumption per mile at a given average velocity of its movement. The influence of a high-pressure fuel system on the optimal control of a vessel diesel engine has been investigated. Thus, the calculated studies indicate that for all values of the parameters of the vessel complex according to the law of control of the fuel system Ф=а+b∙C2(τ), they give fuel savings up to 6% per unit of way in comparison with the law of control of the vessel complex Ф=а+b∙(c1(τ)/c2(τ)). The obtained ratios during modeling and optimal control of the main diesel engine of the vessel complex allow using the dynamic programming method to analyze the fuel consumption per unit path with optimal control compared to the corresponding constant control

A causal supervisory control strategy for optimal control of a heavy-duty Diesel engine with SCR aftertreatment

Diesel engines continue to be the prime movers in heavy-duty and non-road applications. Optimising and controlling the engine and its exhaust-gas aftertreatment system (ATS) for low fuel consumption and low pollutant emissions remains a challenging task. Typically, the engine and ATS are calibrated separately and based on engineering experience. In order to exploit the full potential of the overall system, a so-called supervisory control strategy can be used. In this paper, we develop such a strategy based on Pontryagin’s minimum principle and show that its performance is close to the globally optimal solution. Compared to similar approaches, our concept does not require the optimal control problem to be solved online. Instead, we derive a simple, causal, and near-optimal control law that is easy to implement and tune. We present experimental results from the engine test-bench to demonstrate the practical feasibility and effectiveness of the proposed approach. Furthermore, we show how the strategy can be adapted online using sensor feedback in order to meet a given emission target during arbitrary and unknown engine operation.

Design, Simulation and Control of a Marine Ship Model's Diesel Engine using Python and Matlab/Simulink

Marine ships engines are kind of huge diesel engines. In fact, the manner of controlling the speed of a ship can impact badly on the financial matters of the machinery operation. Thus, controlling the speed of the marine engines can avoid ships to face dangerous accidents. In purpose to prevent such kind of damages, marine systems simulator have been widely used as numerical tools. In fact, the simulation of speed control systems makes it possible to render the process of controlling the speed of an engine economical and eliminates many risks. In this article, we first present a mathematical formulation to illustrate the rotational velocity process of a ship model's marine diesel engine as well as its PID controller. Secondly, we introduce a novel python's marine simulator which includes a PID controller to govern marine ship model's engines and we compare its results with another PID diesel engine speed controller that we modelled, designed and simulated via Matlab/Simulink. Results of scenarios and experiences which we carried out have shown that the response of the speed control system when using python can be accurate and close to the one of Matlab/Simulink.

Prediction model of injection quantity of high pressure common rail fuel system

Objectives In order to provide the basis for accurate control of diesel engine fuel injection quantity, a model method was proposed to establish the main injection quantity prediction model with input parameters as dwell time, common rail pressure and main injection pulse width for the pre-main injection mode. Methods AMESim simulation model was used to conduct simulation experiments and then collect data. Based on the data, the relationship between the dwell time and the main injection volume under single working condition was obtained. On this basis, the influence of common rail pressure and main injection pulse width on the model coefficient was introduced to build a complete multi-working condition main injection quantity prediction model. Multiple input parameter combinations were used to verify the accuracy and reliability of the prediction model of main injection quantity fluctuation. Results The results show that the root-mean-square error (RMSE)of the scheme of multi-working condition main injection quantity prediction model is 1.443 mm3. It can reduce the experiment amount required for modeling from n3orders of magnitude to n2orders of magnitude. Conclusions The proposed prediction model has sufficient accuracy, which is of great significance for engineering application of model-based fuel injection control.

Study of control and stability of diesel engine operation using fractional calculus

The paper presents aspects related to the operation of an electronically controlled diesel engine that equips two cars. Some data related to 100 experimental tests for each car are presented. Some elements related to the electronic control and stability of the Diesel engine are presented by using the fractional calculation to generalize the study.

Hamiltonian Modeling and Structure Modified Control of Diesel Engine

A diesel engine is a typical dynamic system. In this paper, a dynamics method is proposed to establish the Hamiltonian model of the diesel engine, which solves the main difficulty of constructing a Hamiltonian function under the multi-field coupling condition. Furthermore, the control method of Hamiltonian model structure modification is introduced to study the control of a diesel engine. By means of the principle of energy-shaping and Hamiltonian model structure modification theories, the modified energy function is constructed, which is proved to be a quasi-Lyapunov function of the closed-loop system. Finally, the control laws are derived, and the simulations are carried out. The study reveals the dynamic mechanism of diesel engine operation and control and provides a new way to research the modeling and control of a diesel engine system.

Improved method of processing the output parameters of the diesel locomotive engine for more efficient maintenance

Modernization of aged rolling stock is one of the possibilities to adapt it to the current requirements for better environmental friendliness and economy of railway transport. However, some vehicle upgrades lead to new failures that were not observed in the original vehicles. The cause is the so-called “hybrid design”, built on a combination of original and selected new components. The aim of the work was to improve the situation with frequent failures and unavailability that occur on the modernized locomotive where a new diesel engine and new electronic control system was installed. Within the work, a simplified methodology for evaluating the outputs of diagnostic equipment was developped based on and applied to specific locomotive type and its diesel engine. The methodology resulted in a significant reduction of the time for assessing the condition of the vehicle’s diesel engine and more effective maintenance. The paper also presents other possibilities in the analysis of big data in the maintenance of rolling stock e.g. using fuzzy logic.

Aspects Regarding the Functioning of Electronically Controlled Diesel Engines

Aspects Regarding the Functioning of Electronically Controlled Diesel Engines

The effects of Fe2O3 based DOC and SCR catalyst on the combustion and emission characteristics of a diesel engine fueled with biodiesel

The Fe2O3 catalyst exhibits excellent activity in the reduction of nitrogen oxides. However, the improvement of its high-temperature stability is a well-known challenge in application of diesel engine fueled with biodiesels. The paper offers an investigation on the effects of Fe2O3 based diesel oxidation catalyst and selective catalytic reduction catalyst on the engine characteristic of diesel engine fueled with biodiesels and diesel in the experimental study. The catalyst of Al2O3-Nb2O5/CeO2/Fe2O3 was produced with the impregnation method. The characteristics of selective catalytic reduction catalyst and diesel oxidation catalyst were investigated in term of CO, smoke, NOx, CO2 and O2 emissions. In addition, the engine combustion characteristic was studied in term of brake specific fuel consumption, exhaust temperature and excessive air factor. The experiments were carried out with a four cylinders electronic control diesel engine under a constant engine speed of 1000 rpm and various engine loads. The results show that the average increases of BSFC are 10.60%, 5.35% and 5.22% for diesel, RME and CSME catalyst, respectively. In addition, applying of biodiesel fuel drops in CO by 35%, HC by 64%, and smoke by 45% in average, whereas NOx growths by 11% at medium and high loads. The NO conversions of diesel engine fueled with diesel, rapeseed methyl ester and cottonseed methyl ester are up to 72.3%, 81.3% and 78.6%, respectively. Similarly, NOx conversions are up to 76.1%, 82.3% and 83.5%, respectively.

Effects of Coronavirus Induced City Lockdown on PM2.5 and Gaseous Pollutant Concentrations in Bangkok

Partial lockdown measures took effect in Thailand from March 22, 2020 to prevent the spread of the coronavirus. People widely believed that the air quality in Bangkok would improve during the lockdown. This study aims to understand the effects of the traffic on Bangkok PM2.5 and gas concentrations, by comparing the air quality before and during the lockdown. Some pollutant concentrations in pre-lockdown period were higher, but the differences were not significant, except for O3. When results in the full lockdown month, April 2020, were compared to the same period in 2019, the average PM2.5 concentrations at the road sites decreased by 11.1%. On the other hand, it increased by 16.7% at the business area sites. No clear relation of the PM2.5 change to the reduction of traffic and diesel fuel consumption was observed. The reduction of NO2 was clear, caused by the significant drop in traffic and fuel consumption: in turn, it contributed to an increase of O3. The increment of PM2.5 levels during the lockdown was an external effect, even though significant change of local sources occurred. The values of OC/EC ratios in fine particles and the backward trajectory simulation confirmed that the peaks of PM2.5 levels were affected by both transboundary and local aerosol transport from open biomass burning. Hence, it is clear that road traffic, as well as industries or other human activities, were not the most influential factors on high PM2.5 levels in Bangkok in normal conditions. Possible solutions to reduce sources of Bangkok air pollutants include introduction of small-scale machinery for sugarcane harvesting to reduce biomass burning, adoption of higher standards to control diesel engine emission, and mutual agreement and action among ASEAN members in transboundary haze reduction.

Modeling and feedback linearization based sliding mode control of diesel engines for waterjet propulsion vessels

Efficient and stable operation of marine diesel engines is crucial both for navigation maneuverability and safety of waterjet propulsion vessels. In this paper, a piecewise linear model and an affine nonlinear model of marine diesel engines are established by applying mechanism analysis techniques. The models are validated with the experimental data collected from a 290 kW (maximum power) diesel engine equipped on a waterjet propulsion vessel. The relative error of engine speed between model simulation and the measurements is found less than 3%. To improve the performance of the speed regulation system of diesel engines, a sliding mode control strategy is developed on the basis of the affine nonlinear model utilizing the equivalent control method. Simulation results are presented to illustrate the effectiveness of the proposed control strategy regarding model mismatch, response speed, disturbance rejection, and engine speed tracking ability.

Performance enhancement and emission control of diesel engine

In order to solve the problem of emission of harmful gases like Nox, Sox, and CO which are being emitted into the atmosphere and to improve the performance of the engine we have made three subprojects like hydrogen generator equipment, urea injection in exhaust gas flow and a separate chamber to control the emission. In the hydrogen generator equipment, we have made a setup using aluminum rods and baking soda solution to generate hydrogen gas which should be mixed with the inlet compressed air of the engine. Then, the aqueous urea is injected in the exhaust before the Selective Catalytic Reduction (SCR) to increase the conversion of harmful nitrogen oxides to nitrogen and oxygen. At last, the separate chamber is made to absorb the fine carbon particles and to considerably reduce the Sox and Nox emission. Form this analysis engine emits less smoke than normal exhaust as the average value of HSU is 38.01.