DYNATUNE-XL LONGITUDINAL DYNAMICS
DYNATUNE-XL does offers also "Longitudinal Dynamics Tools". Two highly efficient tools have been developed for those people that need to modify their gear ratio's and get the best acceleration package with their available engine or want to improve/design the braking system and verify it's performance. The tools have recently been added to the product portfolio and are focused - as all DYNATUNE-XL tools - to deliver a maximum of information with a minimum of required input data.
Both tools are based on MS EXCEL ® workbooks and do only use standard workbook functions for all calculations (without any additional VBA code) and are therefore fully compatible with all Version of MS EXCEL ® from 2007 onwards.
Both tools are based on MS EXCEL ® workbooks and do only use standard workbook functions for all calculations (without any additional VBA code) and are therefore fully compatible with all Version of MS EXCEL ® from 2007 onwards.
DYNATUNE-XL DRIVE-LINE DESIGN MODULE (DDM)
In RELEASE 8.0 of the Drive-Line Module one can now either provide a classical Internal Combustion Engine (ICE) Torque Map - either directly measured on an Engine Dyno or to be generated out of measured Power at the Wheel Data - as a function of RPM or a Typical Torque Speed Curve from a Motor Generator Unit (MGU). Accordingly one must also provide the Gearbox Ratio(s) & Final Drive Data.
The tool does allow to calculate two vehicles and compare their key performance characteristics.
The tool does allow to calculate two vehicles and compare their key performance characteristics.
Drive-line input data
The user can enter the ICE/MGU RPM/TORQUE Map of the Power Unit with up to 21 data points allowing a precise reproduction of the engine data in steps of 500 RPM from 0 RPM up to 10.000 RPM - or in increments of 1000 RPM from 0 to 20.000 RPM - or in any other desired step size.
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In RELEASE 8.0 the Gearbox does allow from 1 to up to 8 gear ratio's to be specified and can thus simulate the most commonly used Gearboxes for ICE or EV Powertrain Applications in Automotive or Bicycle Engineering Applications.
In RELEASE 8.0 all Drive-Line Rotational Inertia's are considered.
Together with the most important vehicle data, like Vehicle Mass, Weight Distribution, Aerodynamic Data and Tire Grip a typical Gear Ratio / RPM - Velocity Chart provides at the blink of an eye the most important information about the Drive Line Layout.
Drive Line Control Data can be entered. Shifting time can be entered in steps of 0.01 sec and the Power Train Architecture can be varied from FWD to AWD to RWD by 1 Parameter indicating the percentage of Torque transferred to the Rear Wheels. |
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Next to the already mentioned Shift Time for each Gear, Up-Shift RPM and Max. Rev limit of the Power Unit can be set. RPM drops at Gear Shifts are automatically calculated providing the numerical data for the Ratio/RPM Velocity Chart.
Additionally the clutch Stall RPM parameter allows to investigate and find the optimal ICE RPM for Performance Starts. |
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VEHICLE Data
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The most important vehicle data are of course Vehicle Mass, Weight Distribution, Center of Gravity Height and Wheelbase since these parameters define the longitudinal load transfer and wheel loads under Acceleration. Additionally the tool considers the Aerodynamic Data, Tire Rolling Resistance and Road Gradient (included for Hill Climb Racing), since these are the limiting parameters of any Acceleration.
It should be mentioned that the tool is fully capable of simulating high down force vehicles and considers the effects of especially high (negative) Lift & Drag Coefficients on acceleration performance. The axle loads can be generated for any desired speed, if wanted |
RESULTS
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NUMERICAL RESULTS contain the most commonly known numbers that are being used in Performance Tests either related to Time or Distance. All points of interest can be varied without any limits as long as the maximum (simulation) time which is needed to achieve this condition does not exceed 1 minute.
As a guidance the tool calculates automatically the theoretical maximum speed that should be achievable - solely based on the amount of Power available - which will help to identify any potential issues on the selected gear ratio's or final drive. The tool will also automatically calculate the maximum possible accelerations for FWD or RWD and the best AWD configuration (with corresponding Front to Rear Torque Distribution) in order to achieve maximum acceleration at a given speed. In RELEASE 8.0 the Effect of Rotational Inertia's are documented in the Performance Figure Table. |
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GRAPHICAL RESULTS consist out of various Graphs. Next to several Time History Plot's there are two important "major" Graphs:
In the first Graph is the maximum Acceleration of the vehicle is plotted versus it's Velocity for each available Gear considering the limits of Tire Grip and the combined effects of Rolling Resistance, Aerodynamic Resistance & Road Gradient (which is for instance quite important for Hill Climbers). The second Graph plots the sum of all of these limiting factors into the Engine Torque Map allowing the user to see immediately whether the selection of ratio's is optimal or not.
In the first Graph is the maximum Acceleration of the vehicle is plotted versus it's Velocity for each available Gear considering the limits of Tire Grip and the combined effects of Rolling Resistance, Aerodynamic Resistance & Road Gradient (which is for instance quite important for Hill Climbers). The second Graph plots the sum of all of these limiting factors into the Engine Torque Map allowing the user to see immediately whether the selection of ratio's is optimal or not.
The remaining 6 other plots provide all visual information needed to complete the analysis of Vehicle Acceleration, Velocity and Distance. Since Acceleration vs. Velocity is a key metric, this information can directly be confronted with the Saturation of the Tire Grip, allowing to identify when wheel spin occurs (or stops) and what stall clutch RPM would give optimal traction in 1st Gear.
The workbook contains also a COMPARISON Sheet in which all key Parameters and Graphs for 2 Vehicles are listed allowing an easy back to back comparison of variants. Have a look at the DDM PDF file to find out more about it.
