Model Simulation of Electronic Unit Pump Diesel Engine Oriented to Control

Optimising the cam profile of an electronic unit pump for a heavy-duty diesel engine

The fuel temperature has a great influence on the characteristics of an electronic unit pump (EUP) system, especially on the injection performance. This paper studies the regularity of the high-pressure fuel supply system performance at different fuel temperatures. The injection quantity, the injection rate, the fuel pressure, and the needle lift were measured by the EUP system test bench. Investigation results showed that, with the increase of fuel temperature, the injection quantity and maximum injection rate decreased, the time of start injection was delayed, and the peak fuel pressure value decreased. For the needle valve, as the temperature was raised its closing time was advanced at low speed conditions but delayed at high speed conditions. In addition, the empirical equations for the fuel temperature effects on the circulating fuel injection quantity and peak pressure are proposed by the experimental test and simulation data. This study will help to further apply and study the engine, and provide a reference for engine fuel supply control system design.

Electronic unit pump (EUP) can satisfy both diesel engine emission legislation and fuel economy by improving injection pressure and numerical control. Fluctuations in cycle fuel injection quantity (CFIQ) of EUP determine the coherence and stability of the EUP fuel injection system. The EUP simulation model is developed in the AMESim environment. The method for the simulation experiment is designed in the MODDE environment using the design of experiments method. The results of the simulation reveal the variation laws of correlation between parameters with interaction or no interaction under overall operating conditions of diesel engines. In addition, the results also show the EUP system is a complex nonlinear system. Under overall operating conditions, all the characteristic parameters, such as fuel supply pressure, cam profile velocity, control valve lift, injector opening pressure, injector needle lift, and injector flow coefficient, have significant correlation with CFIQ. The interacting first-order factors exhibit the most significant correlation with CFIQ. The self-interacting second-order factors have significant secondary correlation with CFIQ.

The chemical composition and properties of fuels used in compression-ignition engines can influence engine performance significantly. Consequently, the modeling of fuel chemistry within computational fluid dynamics (CFD) simulations of diesel and other compression ignition engines is important. Modern detailed chemical mechanisms may provide predictive modeling of fuel chemistry; however, they are generally far too computationally expensive for use in CFD. We present simulations of diesel engine combustion, focusing on the prediction of ignition, using the CONVERGE CFD software package. A CFD simulation framework with models for turbulence and spray breakup and atomization is presented with a reduced global reaction model to describe fuel oxidation and ignition. The global reaction model incorporates a single parameter, the derived cetane number (DCN), to describe fuel reactivity variability. CFD simulations are compared to experiments carried out in a single-cylinder diesel engine for compositionally diverse conventional and alternative diesel and jet fuels. Model-experiment comparisons show general agreement for ignition timing and the influence of fuel variability on ignition timing. In addition, the sensitivity of CFD predictions on the chemistry, turbulence, and spray models is illustrated.

Development and validation of a new turbocharger simulation methodology for marine two stroke diesel engine modelling and diagnostic applications

These days computer aided simulations are being used to perform hardware in loop (HIL) simulations. This is to ensure the safety and economics, as the real flight test cannot easily be done. Moreover due to the latest controller design techniques, which have further complicated the design implementation, the use of computer is inevitable for control system realization. The HIL simulation in real time validates the theoretical design of attitude control system, the stability of autopilot during the real flight and the consistency between the hardware characteristics and the theoretical analysis. This simulation is carried out in a real time environment and is a major step before the finalization of autopilots and overall control system for the actual flight. This paper presents various steps taken during HIL simulation and the discussion on major test results.

<div class="htmlview paragraph">In this paper, a robust adaptive optimal tracking control design for the air-path system of diesel engines with uncertain parameters and external driver commands is proposed.</div> <div class="htmlview paragraph">First, an optimal controller based on the analytic solution of a performance index is derived. It achieves tracking of suitable references (corresponding to low emissions and fuel consumption) for both the air-fuel ratio and the fraction of the recirculated exhaust gas. Then, a fuzzy estimation algorithm is used to identify the plant parameters and consequently to adapt the controller online.</div> <div class="htmlview paragraph">The simulated diesel engine is a medium duty Caterpillar 3126B with six cylinders, equipped with a variable geometry turbocharger and an exhaust gas recirculation valve. The proposed controller design is based on the reduced third order mean value model and implemented as a closed-form nonlinear model predictive control law on the full order model. The resulting controllers, with and without adaptation, are assessed through simulations with a SIL architecture using dSpace simulator. The adaptive controller, in particular, exhibits good control performance, with zero tracking offset with also ensuring global stability and tracking of output references.</div>

The simulation of direct injection diesel engines requires accurate models to predict spray evolution and combustion processes. Several models have been proposed and widely tested for traditional injection strategies characterized by single injection pulse close to top dead center. Unfortunately, these models show some limits when applied to different injection strategies so that a correct simulation of engine performances and emission cannot be achieved without changing variables included in spray and combustion models. The aim of the present investigation is to improve the prediction capability of the KIVA3V code in case of pilot injection in order to use numerical simulations to define optimized pilot injection strategies. This goal was achieved by eliminating the hypotheses of constant fuel density and constant spray angle in the KIVA3V code and by using a modified version of the Shell model. The proposed modifications to the Shell model allow a better description of low temperature kinetics by the addition of two more radicals and three new kinetics reactions. The improvements in the code were verified by comparing experimental data and numerical results over a wide range of operating conditions including single injections, pilot injections and EGR.

Diesel engines under transient operating conditions are much different from those under steady operating conditions. The paper based on the diesel CA6DL2-35E3 of FAW R&DC with turbocharger, intercooler, four-valve, six-cylinder and high pressure common rail, the diesel displacement is 8.6L. We had established model of the diesel with GT-power and simulated diesel engine working process under transient operating conditions which in constant speed while torque increased, and also analyzed the results. And we had analyzed transient response of burning boundary conditions and max burning pressure.

Globally, many researchers have been trying to improve the fuel economy of a vehicle for satisfying future <TEX>$CO_2$</TEX> regulation and minimizing air pollution problem. For the same background, diesel engine and vehicle system optimization using simulation models have been key technologies for the improvement of vehicle system efficiency. Therefore, in this study, calibration method for the air breathing system of a WGT diesel engine using mean value model has been composed for efficient engine and vehicle optimization simulation researches. And virtual WGT performances have been calculated for a 2 cylinder downsized diesel engine system. From these researches, the calibration method for the boost pressure and EGR rate of a virtual diesel engine related with WGT performances could be composed and some of technical issue related with downsized diesel engine could be investigated.

Tests were done to research the influence of fuel supply map during the starting process of electronic controlled diesel engine in using the electronic controlled diesel engine which was combined with CA498Z diesel engine, VP37 electronic controlled distributor injection pump management system and VS100 calibration system. Calibration process of starting fuel supply map was educed under the principle of low HC emission and rapid starting speed. The calibrating methods of starting fuel supply map were obtained through the tests.

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Diesel engine is vital in the industry for its characteristics of low fuel consumption, high-torque, reliability, and durability. Existing diesel engine technology has reached the upper limit. It is difficult to break through the fuel consumption and emission of diesel engines. VVA (Variable Valve Actuation) is a new technology in the field of the diesel engines. In this paper, GT-Suite and ANN (artificial neural network) model are established based on engine experimental data and DoE simulation results. By inputting Intake Valve Opening crake angle (IVO), Intake Valve Angle Multiplier (IVAM) and Exhaust Valve Angle Multiplier (EVAM) into the ANN Model, and by using SA (simulated annealing algorithm), the optimized results of intake and exhaust valve lift under the target conditions are obtained. According to the optimized results, the fuel consumption of BSFC (brake specific fuel consumption) can be saved by 3.9%, 0.9%, and 7.3% at three different target working conditions, respectively (1000r/min with 50% load, 2000 r/min with 35% load, and 3000r/min with 20% load. Under the three conditions, the intake valve lifts are 1.10, 0.96, 1.10 times as the original respectively and the exhaust valve lifts are 0.98,0.94 and 1.10 times respectively. In addition, by adding the secondary opening strategy of the exhaust valve lift, internal exhaust gas recycling (IEGR) can be achieved. The exhaust gas temperature increased by 9.55% (66.64K) under low-speed working condition, and fuel consumption increased slightly by 6.15%, which is also important for exhaust thermal management and external emission control in the cold start phase of diesel engines. By changing the intake and exhaust valve control, there are obvious differences in the optimal valve lift under different working conditions. Therefore, the application of the VVA system in the diesel engine is of great significance.&lt;/div&gt;&lt;/div&gt;

Diesel engines are widely used in many application domains. The recent drive to reduce emissions, improve efficiency and implement on board diagnostic tools has resulted in a real need for improved models for the simulation of Diesel engines. This paper evaluates three different Diesel engine dynamic models of varying levels of complexity. The assumptions for the models and the equations are presented. The equations are implemented in a computer simulation environment. The models describe the dynamic relationship between indicated pressure and engine speed. The first model is a detailed analytical non-linear dynamic model, including dynamometer dynamics, instantaneous friction components, viscosity variations with temperature and inertia variations with piston pin offset. In-cycle calculations are performed at each crank-angle. The second model is a nonlinear dynamic model which includes a mean friction model for the engine components and dynamometer dynamics, but does not include the piston pin offset as well as the inertia variations. The third model is obtained by an identification procedure to find a low-order linear transfer function between the engine input and output. The three models are used to predict the behaviour of a Diesel engine. The models are compared using experimentally measured engine speeds, under steady state and transient operating conditions. The paper discusses the suitability of the models for various control applications such as engine simulation, fuelling control system design and fault diagnostics.

This paper describes the application of the fuzzy neural network system (FNNS) to improve the performance of the pump of a heavy-duty diesel engine according to the diesel engine real-time control system. This is a kind of intelligent control system that can be used without knowing the system's model and it can choose the control model on-line. This system is suitable to control nonlinear, time-varying, ill-defined systems such as vehicle diesel engines. A FNNS can be constructed automatically by learning the training examples itself. It can create and modify the fuzzy control rule table, it can also choose optimal input or output membership functions, so satisfactory results can be received. This system is used to control fuel quantity by loop control of pump rack position. By using this system, this optimum control and timing control are implemented. From the system's test, the efficiency of this system was demonstrated.

In order to achieve different response indifferent moment of fuel Injection Solenoid, a driving mode of Peak&amp;Hold is generally applied to electronic control fuel injection system of the diesel engine. The theoretical analysis of high speed response and duplicate supply drive circuit based on the energy recovery is made, and a theoretical guidance for optimization design is presented. According to an electronic unit pump developed by ourselves, the optimization design of drive circuit for the fuel injection system is done. The results showed that during the process of injection, the time of current of solenoid valve form 0 to 20A is 224, and the turn-off time is 120which is a little longer than that of the high speed circuit based on the avalanche. And the turn-off time is met the requirement of control precision. With many advantages, such as energy saving and heat reducing, the high speed response and duplicate supply drive circuit based on the energy recovery will become a good choice in electronic control fuel injection system.