Input Data

On this page you will find all of the different parameters needed to run umhr. You can print out this page and use it as a template to gather the data. The following list below takes you to a number of different sections which are used to differentiate between the different sets of data. Clicking the mouse on each section header takes you to the Graphical User Interface (GUI) used for entering the data.

    • The experimental data needed to run the program is selected from this GUI.
    • This GUI can be used to filter the experimental data to reduce the noise inherent in capturing the data.
    • The basic geometry of the engine is entered in this GUI.
    • This GUI is used for entering parameters that may change based on the operating conditions of the engine.
    • A number of different GUIs are linked together in this section to allow the user a number of different ways to calculate the properties of the gas in the cylinder. The user has options to select how to calculate the gas constant, ratio of specfic heats and/or constant volume specific heat. There is also the option to use an equilibrium program to calculate the properties.
    • This GUI allows the user to select one of many heat transfer correlations that are available in the literature. The user also has the ability to change the constants in these different correlations.
    • In this GUI, the user can change a few computational features in the program.

Parameter
Units
Description
Input File
[-]
Input Text File: Tab delimited
CA [°] Pressure [Pa]
Number of points in input file
[-]
Number of points in input file
Crank Angle Resolution
[-]
Crank angle resolution of input data
Output File
[-]
Writes all output to a file which is read by the GUI

The IMSL and CXML libraries can be used within the program to smooth the data. If you are working from the FORTRAN source and do not have either of these libraries on your computer (you will have to link to them while compiling), then you should comment out those lines of code that use them. Otherwise, if you don't, you will encounter a number of linking errors when trying to build the executable version.

Parameter
Units
Description
Data Smoothing Switch
[-]
0 - No smoothing 1 - Real Trigonometric (IMSL)
2 - Real Quarter Sine (IMSL) 3 - Real Quarter Cosine (IMSL)
4 - DFFT (CXML) 5 - DFCT Type 1 (CXML)
6 - DFCT Type 2 (CXML) 7 - DFST Type 1 (CXML)
8 - DFST Type 2 (CXML) 9 - Digital Filtering (CXML)
Number of Points to Keep
[-]
Number of terms to keep after smoothing the input data. To keep all of the points, make this equal to the number of points in the input file (or select 0 - No Smoothing from above)
Low Filter
[-]
Digital Filtering Option #1
High Filter
[-]
Digital Filtering Option #2
Wiggles
[-]
Digital Filtering Option #3
Nterms
[-]
Digital Filtering Option #4

Parameter
Units
Description
Bore
[m]
Cylinder bore
Stroke
[m]
Cylinder stroke
Compression Ratio
[-]
Compression ratio
Connecting Rod Length
[m]
Connecting rod length
Cylinder Head Surface Area
[]
Calculated surface area of the cylinder head
Piston Crown Surface Area
[]
Calculated surface area of the piston crown
2 or 4-Stroke Engine
[-]
Enter 2 for a 2-stroke engine, 4 for a 4-stroke engine

Parameter
Units
Description
Engine Speed
[rev/min]
The speed of the engine at which the input data was taken
Wall Temperature
[K]
The wall temperature of the cylinder (possibly separate into head, wall and piston temperatures).
Intake Valve Closing
[deg]
IVC in reference to input data.
Exhaust Valve Opening
[deg]
EVO in reference to input data.
Injection or Spark Timing
[deg]
This is when the heat release program will start calculating the mass fraction burned data.
Top Dead Center Adjustment
[deg]
This is where TDC is in the input data. The user can also adjust for the Thermodynamic Loss Angle (TLA) here.
Constant/Variable Mass Switch
[-]
Currently only constant mass in the cylinder is available.
Air Flow Rate/Equivalence Ratio Switch
[kg/cyl/s] / [-]
The user can enter in either the air flow rate or the equivalence ratio
Mass Flow Rate of Fuel
[kg/cyl/s]
Measured mass flow rate of fuel into the cylinder.
Residual + EGR
[%]
The amount of burned mass left over from the previous cycle [residual] plus the amount of exhaust gas recirculation [EGR].
Title
[-]
The title that will show up in the windows.

Parameter
Units
Description
Initial Gas Constant
[J/kg/K]
This is the initial gas constant used by the program the first time through the calculation to generate profiles needed. It is also used when the constant gas constant option is chosen.
Initial Ratio of Specific Heats
[-]
This is the initial ratio of specific heats used by the program the first time through the calculation to generate profiles. It is also used when the constant specific heats option is chosen
Stoichiometric Air/Fuel Ratio
[-]
Stoichiometric Air/Fuel ratio
Lower Heating Value of Fuel
[kJ/kg]
Lower heating value of fuel
[-]
0 - Constant gas constant 1 - Krieger/Borman correlation (1966)
[-]
0 - Constant ratio 1 - Gatowski (1984, indolene)
2 - Gatowski (1984, square piston, propane-air) 3 - Brunt, Rai and Emtage (1998, gasoline)
4 - Brunt and Platt (1999, diesel)  
[-]
0 - Calculate from gas constant and ratio of specific heats 1 - Krieger/Borman (1966)
2 - Hohenberg/Killmann (1982, gasoline) 3 - Hohenberg/Killman (1982, diesel)
[T/F]
Use equilibrium routines for gas properties
Air Properties - Mole Fraction
[-]
composition of air
Air Properties - Mole Fraction
[-]
composition of air
Air Properties - Mole Fraction Ar
[-]
Ar composition of air
Air Properties - Mole Fraction
[-]
composition of air
Fuel Properties - Moles Carbon (a)
[-]
Carbon from
Fuel Properties - Moles Hydrogen (b)
[-]
Hydrogen from
Fuel Properties - Moles Oxygen (c)
[-]
Oxygen from
Fuel Properties - Moles Nitrogen (d)
[-]
Nitrogen from
Fuel Thermodynamic Properties
[-]
The user can select which fuel thermodynamic properties they wish to use.

Parameter
Units
Description
Heat Transfer Correlation
[-]
0 - Constant coefficients 1 - Nusselt (1923)
2 - Brilling (1931) 3 - Eichelberg (1939)
4 - Elser (1955) 5 - Taylor/Toong (1957)
6 - Oguri (1960) 7 - Overbye (1961)
8 - Van Tyen (1962) 9 - Annand (1963)
10 - Woschni (1967) 11 - Lefeuvre (1969)
12 - Annand (1970/71) 13 - Sitkei (1972)
14 - Dent (1977) 15 - Hohenberg (1979)
16 - Annand (1980) 17 - Kornhauser (1994)
18 - Han (1997)  
Heat Transfer Parameters 1-20
[-]
These are the coefficients in the various heat transfer correlations presented above. Please consult the user’s guide for a description of each heat transfer correlation

Parameter
Units
Description
Order of Numerical Derivative
[-]
When taking the derivative of a variable, the user can choose 1st, 2nd, 3rd or 4th order accurate finite discretizations
Maximum Number of Iterations Allowed
[-]
The user can select the maximum attempts at convergence for the iterative scheme.
Convergence Criterion
[-]
The criterion between successive iterations that needs to be reached for numerical convergence.

Unless otherwise expressly stated, all original material of whatever nature created by Dr. Christopher D. Depcik () and included in this website and any related pages is licensed under a .
Creative Commons License
Date Created: 05/28/2003
Date Revised: 10/11/2005