Diesel-RK is an engine simulation tool

DIESEL-RK is a full cycle thermodynamic engine simulation software. One is designed for simulating and optimizing working processes of two- and four-stroke internal combustion engines with all types of boosting. The program can be used for modeling the following types of engines:

• DI Diesel engines, including PCCI and engines fueled by bio-fuels.
• SI petrol engines.
• SI gas engines including prechamber systems, and engines fueled by different gases: Methane, Propane-Buthane, Biogas, Wood gas, Syngas, etc.
• Two-stroke engines with uniflow and loop scavenging, opposed piston engines (OP or Junkers engines) and OPOC engines.
• Dual fuel engines (engines having few independent fuel injection systems for different fuels). (Engines with RCCI)

    The DIESEL-RK is a thermodynamic tool: engine cylinders are considered as open thermodynamic systems.

   Representative applications include:

• Fuel consumption prediction and optimization.
• Torque curve and other engine performances predictions.
• Combustion and emission analysis, including PCCI / HCCI.
• Dual fuel engine mixture formation and combustion analysis.
• Knock prediction.
• Valve timing optimization, including VVA optimization for every operating mode.
• EGR analysis and optimization.
• Turbocharger and bypasses matching and optimization.
• Conversion of diesel engines into gas engines.
• Cooperation with different modeling tools: Simulink, IOSO NM, etc.: DIESEL-RK solver can be run under the control of other applications.

Main features of program DIESEL-RK are similar to known programs: WAVE (Ricardo Software), GT-Power (Gamma Technologies) and BOOST (AVL). However, together with conventional abilities, the program DIESEL-RK has new advanced features:

• RK-model :  is a multi-zone diesel fuel spray mixture formation and combustion model.
• Fuel Spray Visualization tool (easy flat and advanced 3D).
• Multiparametric and multidimensional optimization of engines parameters. A target function including NOx, Soot and SFC simultaneously may be calculated as inside DIESEL-RK, as with User Defined procedure being done as DLL and linked with DIESEL-RK kernel.
• 1D and 2D parametrical researches procedures.
• Detail Kinetic Mechanism of NO formation (199 reactions, 33 species) is implemented for PCCI, multiply injection and high EGR analysis. (Zeldovich mechanism does not work correctly at large EGR and multiple injection. One shows too small emission in comparison with experimental data.)
• DIESEL-RK support simulation of water injection and account H2O condensation and evaporation in intake manifold, port and cylinder. 

       RK-model simulates mixture formation and combustion taking into account:

• Piston Bowl Shape: any geometrical shapes can be specified and saved into the piston bowl data base which already includes the most common geometries;
• Different Swirl Profiles and swirl intensity;
• Sprayer Location: central, non-central, side injection, few sprayers;
• Number, Diameter and Direction of sprayer nozzles (each sprayer may have nozzles with different diameters and arbitrary orientation);
• Fuel Properties, including bio-fuels and blends of bio-fuels with diesel oil (data base of fuels is supported);
• Shape of injection profile including multiple injection and PCCI; Optimization of injection profile flanks shape; Optimization of Multiple Injection Strategy;
• Detail Chemistry is calculated at the Ignition Delay prediction for PCCI with diesel fuel and biofuel. RK-model accounts a CR high pressure effect on Ignition Delay;
• Low Temperature Combustion is modeled at PCCI and HCCI;
• Interaction of the Sprays with Walls and with other Neighboring Sprays (as on wall, as in volume);
• Local Temperature of the wall in the region of impingement the sprays with a wall.

The RK-model has a capability to optimize the piston bowl shape and fuel injection system parameters (sprays directions, diameter and number of nozzles) as well as to develop multiple injection strategy and the Common Rail controlling algorithm over the whole operating range.

Fuel spray evolution visualization tool The DIESEL-RK includes  "Fuel Spray Visualization" code. This code allows engineers to present in the animation picture format the results of modeling of interaction of the fuel spray with combustion chamber walls, air swirl and with neighboring sprays. The code assists in choosing the best shape of the piston bowl and select the diameter, the number and the directions of injector nozzles for a given injection duration and swirl intensity. Results of simulation can be saved as Windows graphic files, AVI or animated GIF files. Visualization is possible as flat picture, as in 3D.

3D visualization of sprays evolution in cylinder of two-stroke low speed large marine diesel engine 

3D tool allows analyze spatial evolution as of all sprays, as of one or few sprays. Visualization tool has capabilities to mark each characteristic zone of every spray by specific bullets to observe the volumes where sprays impinge walls and disturb each other in volume or near the wall. The combustion model accounts effect of these zones on Heat Release Rate. The real shape of piston bowl and cylinder cover is accounted at simulation and visualization.  This function is very important for optimization of combustion in large marine two-stroke diesel engines with side injection system.

In the pictures the sprays spatial intersection zones are shown by light green bullets.  

Effect of sprays spatial intersection on Heat Release Rate is presented below. On the right HRR diagram the intersection phenomenon is not accounted; in the left the effect is taken into consideration.

DIESEL-RK preprocessor is very easy in use: Wizards allow beginners working without especial training; Detailed Engine Description provides wide range of research abilities for experts. Preprocessor makes it possible to set and research any piston bowl shape and any fuel sprayer design. Data base of piston bowls is supported.

Optimization library and parametrical research tools. To perform an optimization calculation the DIESEL-RK is equipped with a built-in procedure of multiparametric and multidimensional optimization which includes 14 methods of nonlinear optimization search. There is also a possibility to perform 1D and 2D parametrical search investigations. Optimization tools allow engineers to considerable increase the efficiency of computational research providing effective ways to improve the engine design. For simultaneous optimization of few engine parameters: NOx, Soot and SFC the target function including list of engine parameters may be calculated with User Defined Procedure being done as DLL and linked to the existing DIESEL-RK kernel. Pareto-optimization is possible if DIESEL-RK will be run under control of external optimizer.

SAE Pap. No 2009-01-1956

Premixed Charge Compression Ignition (PCCI) analysis. Simulation of combustion at Multiple Injection and simulation of the PCCI or Split Combustion are supported. The specific feature of PCCI is a very early start of multiple injections of pilot portions of fuel. Low Temperature Combustion and High Temperature Combustion are modelled. The Ignition Delay for every portion may be  calculated using different methods including user defined model, phenomenological models, or Detail Chemistry Models, for example implemented Lawrence Livermore National Laboratory mechanism which considers 1540 reactions between 160 species. See detailes... The DIESEL-RK interface includes special tool for multiple injection specification. Using this tool it is possible to select and optimize automatically a duration and fraction of pilots to exclude the hitting of the fuel on the liner and to arrange optimal combustion . See visualization.

Kernel can be run under a control of external application. In order to run DIESEL-RK kernel under the control of external codes intended for optimization or for simulation of vehicle where the engine has been used, the special interface is developed. The interface includes text files with input data and output data. The DIESEL-RK solver may be run by external code via batch file. For example DIESEL-RK is compatible with multi-objective optimization software IOSO NM

Variable Valve Actuation analysis. Valve Lift Diagram with variable valve actuation can be setup and optimized individually for every operating mode. The Valve Dwell optimization takes also into account the duration and valve lift of the dwell

Advanced Ignition delay prediction model The classical equations intended for Ignition Delay prediction do not work properly at modeling PCCI and under other conditions characterizing large EGR, small temperature, long period of the delay, etc. The Detail Chemistry is modeled for these cases, and Ignition delay is calculated as a function of pressure history, temperature history, EGR history and current Air/Fuel ratio for diesel fuel as well for bio-fuel. The Lawrence Livermore National Laboratory mechanism which considers 1540 reactions between 160 species is used. A User Defined Model may be used for ignition delay prediction. There is ability to link User Model DLL with DIESEL-RK  SAE Pap. No. 2010-01-1960

Simulation of engines with few Fuel Injection systems DIESEL-RK supports simulation of an engine having up to 5 independent fuel injection systems (marked as A, B, C, D, E). Every system may have own configuration with own number of injectors, mounted in different places of the cylinder. Each injector may have few nozzles with individual orientation in both planes and different diameters.  Each fuel system may have own cycle fuel mass and own injection profile. So the Sequential Injection Profiles are supported at Heat Release simulation and NOx simulation. Because each system can inject own fuel the Dual Fuel Engine simulation is supported.

Dual Fuel Engine Simulation DIESEL-RK supports simulation of an engine having up to 5 independent fuel injection systems. One of the system may assigned as Pilot Diesel Injection System; and another as Main Alternative Fuel Injection System. See details >>.

Coupled simulation of the mixture formation and combustion and prediction of the thermal state of engine components. Fuel evaporation and combustion as well as heat losses to the walls are calculated using local wall temperatures obtained with the use of Finite Element Model of main engine parts. Boundary conditions depend on the cooling system design and piston ring assembly. The program includes data base of geometry of: - pistons, - liners and cylinder heads; which will be reflected by a preprocessor.

Being professional, the DIESEL-RK can be also used with success by beginners, students and post-graduate students of high schools. For simplification at times labor-intensive process of data set (especial empirical coefficients) in the program a special tool is developed: Wizard of New Project Creation. This wizard on the basis of the most common data about engine will create file of input data, using the most known technical decisions accepted in area of propulsion engineering. Thus it is becomes simpler not only a process of input data entering but also the most difficult stage of computational research: calibration of engine models. The last is especially important for the engineers who are not having enough time and experimental data for customizing of the program on object of research, and also for researchers who makes express engine analysis.

Skilled expert can use all abilities of advanced simulation methods of the DIESEL-RK software by calibrating models with coefficients obtained on experimental data.

     Calculated curves can be exported via clipboard into external applications (Excel, etc.).

     Calculation of NOx emission is carried out by two ways. User can select NO formation model from the list:

• Zeldovich's mechanism taking into account a chemical equilibrium of 18 species may be used for conventional diesels.
• Detail Kinetic Mechanism (DKM) or correct prediction of NO emission in engine with large EGR, multiple injection and HCCI (199 reactions, 33 species). DKM is supported by the local release of DIESEL-RK.

In the local version of the software the User Defined Models may be implemented for:
- Friction losses simulation;
- Ignition Delay simulation;
- Forming and calculation of a Target Function for optimization Complex of emission (NOx, Soot or PM and SFC).

Users Defined Models have to be developed by user as DLLs. Examples of FORTRAN sources are presented in the distributive kit.

To make the DIESEL-RK be accessible to users, the remote access via INTERNET is provided.  For remote access to the program it is enough to download file with SETUP.EXE and to install client software on local computer.

List of input engine data can be downloaded here.