MOTA USER GUIDE

MOTA USER GUIDE
A Two-stroke Engine Simulator with Input/Output Support Routines

Installing MOTA
Follow the instructions printed on the CD to install MOTA on to your computer, MOTA will not run from the CD. In order to run MOTA you need to plug the supplied USB HARDLOCK dongle into a USB Port of your computer. . Your program serial number is written on the dongle. Make sure to include this number on your registration form before posting or faxing it back.

Using MOTA

To start MOTA, double click the MOTA icon installed on your desktop during the program installation. When you open MOTA the main menu screen is displayed. MOTA uses information that is stored in files called `Engine Data Files'to run the engine simulator which then creates `Engine Performance' and `Engine Graphics' output files. All of these MOTA files can be accessed through the items under the first main menu selection, the File sub-menu. At any time while in MOTA, pressing the F1 key will open the User Manual in your computer's web browser.

NEW ENGINE DATA FILE

Allows you to specify the characteristics and dimensions of the engine you wish to simulate. Various screens can be selected from the main engine data file construction screen within this option, allowing you to enter your engine's characteristics in a logical manner. Selecting the `Save the File' option from this main screen, you can then enter a name for your new enginee data file to save it to the folder of your choice, with a ".DAT" extension -It is strongly recommended that you use the Edit a Data File facility to view a completed Engine Data File before attempting to create your first file from scratch

EDIT EXISTING DATA FILE

Allows you to select an existing engine data file, edit it, and then, save it under it's original name or under a new name.

VIEW AN ENGINE PERFORMANCE FILE.

Allows you to look at the output Performance File written during an engine simulation. This file has the same name as the engine data file, but with the extension ".PER". This Engine Performance File contains all of your input data and other calculated values such as specific port time-areas and compression ratios as well as the various results calculated by the MOTA engine simulator, like power and torque, BMEP, flow and scavenge ratios, fuel consumption etc.

DISPLAY ENGINE GRAPHICAL INFORMATION.

Allows you to examine the Graphics Output File written during an engine simulation.This file has the same name as the engine data file, but with the extension ".GPH". A wide range of graphics displays can be viewed, including the ability to overlay power/ torque curves from other engine simulations. A utility provided under this menu allows the conversion of MOTA version 5 engine data files to compatible version 6 files for users who have upgraded from the previous version of MOTA. Run File Selection

RUN THE SIMULATOR

Opens a window allowing the selection of one or more Engine Data Files with which to run the engine simulator - this is the heart of the MOTA package. The simulator accesses a data file with a ".DAT" extension, performs an engine simulation run and writes two files with the same name as the engine data file but with the extensions ".PER" and ".GPH". The first file provides information about the engine's performance in a text format. The second file provides information for a graphics postprocessor which can then be used to display both stationary and animated views of the engine's performance. These two files are always written to the same drive and folder as that containing the engine data file used for the simulation, and both are accessed from selections in the File sub-menu.

THE TOOLS

The Tools sub-menu provides utilities for calculating and converting engine related parameters.

Piston Position to Crank Angle converts a piston distance from top dead centre to a crank angle.
The inverse function is Crank Angle to Piston Position

Chord Length to Arc Length converts a straight line distance between two points on a circle to the length of the arc joining the same two points. The inverse function is Arc Length to Chord Length.

Bridged Port Radial Attitude Angle calculates the effective radial attitude angle of a bridged port.

Rectangular Duct Equivalent Diameter calculates the diameter of a circular duct with the same cross-section area as that of a given rectangular duct.

Integrated Muffler Length calculates the length of an integrated muffler of defined muffler volume space

Integrated Muffler Volume calculates the muffler volume space of an integrated muffler.

EXPANSION CHAMBER CONSTRUCTION MODULE

Allows you to use expansion chamber data from a MOTA engine data file or from values you enter through the keyboard, and outputs the dimensions of flat sheets of metal which, when rolled and welded, create the expansion chamber cones. An explanatory screen comprising diagrams and a legends table is also provided as a selection from the sub-menu of this selection.

THE POWAPLOT UTILITY

. Is provided to enable the easy comparison of the performance of an engine as measured by a dynamometer with that predicted by the MOTA engine simulator. It involves the construction and use of files having a ".POW" extension which contain a set of values of engine speed and power.

CONSTRUCT A POWER FILE FROM A GRAPHICS FILE

Extracts the power curve information from a nominated engine graphics file produced by a MOTA engine simulation and writes it to a new file with the same name and a ".POW" extension.

CONSTRUCT A POWER FILE MANUALLY

Allows you to enter values of engine speed and the corresponding power or torque through the keyboard and then save this information to a file with a ".POW" extension. You may nominate the input units ( imperial or metric ) and also whether the speeds will be in equal increments in which case the initial speed and the increment only are entered

DISPLAY A POWER FILE

Under "Display a Power File" you can select a power file, and the power/torque curves representing the values in this file are then displayed. Many display options are provided such as the change of display units, the change of scales and the selection of other power and/or graphics files to provide overlay curves to the display. The overlay facility allows the easy comparison of different engine performances.

REGISTRATION & HELP

To enable us to provide assistance with your questions, and to keep you informed of upgrades, please complete the registration card and post or fax it back. The main menu item "Help" opens a sub-menu with a further selection of "User Manual". This will open a full version of the MOTA User Manual in a browser window so that you can read the complete instructions for using MOTA. It includes a full set of diagrams and descriptions of the terms used in MOTA, and the entire contents or any selection of pages may be output to your printer

An Overview of MOTA

The name MOTA is used to cover the complete suite of programs which build, modify and run engine data files, and process the graphics and engine performance output files.

Because MOTA solves the equations describing the conservation of fluid and thermodynamic properties throughout an engine, it requires the specification of the full engine geometry. This is accomplished through a menu driven environment which prompts you for the required dimensions.

The engine simulator in. MOTA uses data supplied from an Engine Data File which is constructed by completing a set of Windows-based screens which prompt you for information about your engine. The engine simulator outputs information to a text based Engine Performance File which summarises the engine's geometry and performance, and to a Graphics File which is used to depict various aspects of the engine's performance graphically. Facilities within the MOTA environment allow for viewing of this information.

The strength in MOTA lies not so much in it's ability to predict accurately the performance of an engine, but in it's ability to compare the performances of different engine configurations. For example, if you have the MOTA generated power curve for an engine, and you want to see if modifying one of the exhaust pipe dimensions will increase or decrease it's power, then you can change that particular dimension and re-run the engine simulator in MOTA. Comparison of the new power curve with the old will allow you to determine whether or not the change will be beneficial.

MOTA will simulate one of the cylinders of a multi-cylinder twostroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a separate exhaust system and a separate induction system.

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