Dyno2 Dynamometer Software – working in run tab

RUN tab is used to make new measurement and to work with the car by using dyno brake and speed control.

Elements of RUN tab
  1. START / STOP – start or stop saving measurement data
  2. Save to database checkbox allows disabling registering new runs in projects and runs database. Run data is still stored as a file in the file system in case something important happens during the test, and it needs to be recovered.
  3. Automatic START / STOP enables starting and stopping the run automatically by monitoring the dyno road speed.
  4. Automatic start speed. When the speed goes above this value, the run is started.
  5. Automatic stop speed. When the speed goes below this value, the run is stopped.
  6. ANALYZE LAST RUN – shortcut for loading measurement data to ANALYZE tab after finished run
  7. Current run name. It can be used to label the run like i.e. warm-up, stock, tune. If the project have a run with the same name, a number after the name is added and incremented. i.e. “stock”, “stock 1”, “stock 2”.
  8. Current run comment. It can be used to describe the run in few more words than the run name.
  9. Engine speed source selection widget is used to select the source for engine speed used in calculations. Following options are available:
    • calculated – the engine speed is calculated with a constant ratio to dyno roller speed. This is the primary, general purpose choice for measurements.
    • engine clamp – the speed is sourced from “Engine speed” input in the controller. You can use this option through the whole run or if the speed signal is glitchy you can switch to this option to get the speed ratio and the switch back to “calculated” mode.
    • OBD – the speed is continuously sampled from OBD interface. Keep in mind that OBD is relatively slow and has low sampling rate. With this option you will get precise engine speed values, but in between samples the values will be interpolated.
    • CAN channel – the speed is taken from manually configured CAN-bus message.
  10. Engine speed ratio for calculated engine speed source. The ratio can be automatically calculated by using tools available on right click:
    • Set from current engine speed – the ratio is calculated from current speed using entered engine speed.
    • Set from max engine speed – the ratio is calculated from maximum recorded speed using entered peak engine speed.
    • Get from OBD – the ratio is calculated from OBD interface information.
  11. Loss model – model used to estimate power lost in the drivetrain and on the tire-roller contact patch. The model is used to calculate engine power from the power measured on dyno rollers. Loss model calculation tool is available by right-clicking on the Loss model label. Once measured and calculated, the model can be attached to new runs to avoid doing coastdown every run.
  12. Brake controller – widgets responsible for controlling absorption dynamometer absorber.
  13. Brake controller basic modes:
    • Brake OFF – dyno absorber is disabled
    • Torque control – each brake channel is controlled manually and separately by sliders (18)
    • Torque c. joined – all brake channels are controlled manually together by sliders (18)
    • Speed control – the software keeps engine speed constant
    • Accel. control – the software keeps engine acceleration or deceleration constant
  14. Brake controller control variable. The control can be based on dyno road speed or on engine rotational speed.
  15. Min speed. This value is used to avoid engine stalling. Absorber is always disabled below this speed. This value is also used as minimum limit in advanced tests.
  16. Speed target for Speed control mode.
  17. Acceleration target for Acceleration control mode.
  18. Desired torque sliders for Torque control modes.
  19. ADVANCED TESTS SELECTOR – run predefined, more advanced dyno tests that run over the brake controller basic modes. The available tests are:
    • Road simulation – the test will control vehicle acceleration based on entered parameters such as vehicle mass, air drag and hill angle.
    • Advanced ramp test – powerful ramp test that includes automatic test start and stop, predefined hold speed and ramp rate, top hold, accelerated coastdown and automatic switch to ANALYZE after the run.
    • Ramp test – simple ramp test with hold speed and ramp rate.
    • Sequence – test with programmed speed limit and throttle opening curves
  20. Throttle control – value used to control engine throttle. More information about throttle control can be found on the throttle control page.
  21. Outputs control – this section of the application shows current controller output state and allows controlling their state.
  22. Desktops bar – shows currently opened desktops (workspaces) and allow manipulating them.
  23. Desktop area – area that can be freely configured by user and is used to visualize information channels available to dyno software.

Using Loss Model in RUN tab

Loss model can be used in RUN tab to calculate the engine power on the run using losses estimation from previous run.

Basic brake controller modes

Brake controller provide some basic brake operation modes that are sufficient for using the dyno for tuning and plotting power curves. The modes available are:

  • Brake OFF – in this mode the absorber is disabled, and the dyno runs like an inertial only dyno. It is good to make smooth and repeatable power curves. If the dyno rollers inertia is low and the car is turbocharged, this mode can give lower power results than the modes with absorber, as the turbo won’t have enough time to spool up.
  • Torque control – this mode provides control over the torque load of the absorber. This mode is suitable for turbocharged cars and for making smooth, repeatable power curves for a customer.
  • Torque control joined – mode similar to one above, but all absorber sliders are locked together.
  • Speed control – mode used for engine control unit tuning. With this mode, we order the dyno to keep the dyno and engine speed constant. By doing it, the dyno locks the engine speed coordinate of the ECU map. We can move on load coordinate of the ECU map by operating the throttle. This allows precise tuning of the ECU maps.
  • Acceleration control – this mode keeps engine acceleration or deceleration at a constant value. This mode is useful to do power sweeps for tuning or making engine characteristics for a customer. In case of chassis dyno, the power curves from this mode can be more “wavy” than the ones from Brake OFF or Torque control modes. It’s a result of the PID controller fighting to get the acceleration at a desired value and the car using its freedom to move on the rollers. The results depend on how tight the car is strapped to the dyno and how aggressively the PID controller is set up. With relaxed PID setup, this is a very good mode for making engine characteristic plots. In case of engine or PTO dynamometer, where coastdown is not required, a good method to make the measurement is to accelerate the engine to top speed and then start the test with negative acceleration value.

Steady state demo on MAHA dynamometer converted to DC1 controller

Advanced tests

Road simulation

The road simulation advanced test mode uses configured parameters and measured speed and power to control vehicle acceleration on the dyno:

Acceleration target = f(dyno speed, power on wheels, parameters)

This will simulate how the car would behave while driving on the road.

  1. Parameters of vehicle and road
  2. Calculated resistance forces that acts on the vehicle

Advanced ramp test

The advanced ramp test is designed to speed up engine characteristic measurement and to solve some common phenomenons that distort engine characteristic curve.
To speed and ease the measurement process, the advanced test provides:

  • Automatic run start,
  • Commands for inexperienced dyno operator,
  • Accelerated coastdown phase for time saving,
  • Automatic run stop and switch to ANALYZE tab.

The common phenomenons that distort engine characteristic results are:

  • With simple acceleration mode, the turbo of the turbocharged engine may not have enough time to spool up. As a result, torque and power in lower speed range and sometimes in the whole range are lower than the maximum that the engine can produce when fully loaded. To solve this, the engine is held at a constant preset speed to spool the turbo at the start of the run.
Effect of not letting the turbocharger enough time to spool up. Same car setup with and without hold at 1500 RPM.
  • When during standard test procedure the clutch is depressed at the top engine speed, the power transfer from vehicle to dyno instantly drops. Due to use of zero-phase filtering, which is required to correctly filter (smooth) the graphs, the end of the power and torque curves fall down below the real power output of the engine. The significance of this effect depends on how strong the filtering (smoothing) is set up. To solve this, the engine is held at top speed and high power for some time before pressing the clutch
When using top hold, the power and torque curves are not smoothed down at the end. Example comparison with 1Hz filter cutoff frequency.
  1. Automatic start speed
  2. Turbo spool up hold speed
  3. Turbo spool up hold time
  4. Acceleration ramp rate
  5. Top hold ease in speed
  6. Top hold speed
  7. Top hold time
  8. Accelerated coastdown rate – warning: high accelerated coastdown rate will distort free rolling speed loss measurement
  9. Automatic stop speed
  10. Test mode: road speed or engine speed
  11. Current test state
  12. Operator command

Ramp test

The ramp test extends basic acceleration mode with hold at a preset speed for turbo spool up.

  1. Test mode: road speed or engine speed
  2. Ramp mode:
    • Speed controlled ramp – this ramp uses constant speed mode of the brake controller by increasing the target speed constantly to achieve desired acceleration. In this mode, the engine or dyno speed will follow the anticipated speed ramp faithfully. This mode can cause loops on engine characteristic plots. If the engine power increases rapidly, and it accelerates above the desired speed, it will be pulled back to this desired speed.
    • Acceleration controlled ramp – this ramp uses constant acceleration mode of the brake controller. In this mode, the controller will work to keep the acceleration as desired level. If the engine power increases rapidly, and it accelerates faster than the desired target, the controller will correct the acceleration, but it won’t stop it to get back on the theoretical speed ramp.
  3. Hold speed – the speed that is held to spool up the turbo
  4. Hold time – time to spend at hold speed to spool up the turbo
  5. Release time – transition time from hold to full acceleration
  6. Acceleration rate
  7. Tracking threshold – this value has several uses in the algorithm, and is generally used to inform it, what amount of error between desired speed and actual speed should be accepted.
    • During hold state, if (|current speed – hold speed| < tracking threshold), the hold time is counted down to pass to the next state. If the speed difference goes above the tracking threshold, the timer is reset.
    • During acceleration state in speed controlled ramp if (current speed > target speed – tracking threshold) the speed target is increased. In other case, the speed target is reduced, so we can start accelerating again.
    • In acceleration state, if (current speed < hold speed – tracking threshold) the hold state is activated again
  8. Current test state
    • ARMED – the test is ready. Accelerate at will.
    • HOLDING – the test is holding the Hold speed.
    • RELEASING – the test is in transition between HOLDING and ACCELERATION
    • ACCELERATION – the test is controlling acceleration at rate entered in Acceleration rate field.
Speed (thick line) vs acceleration (thin line) controlled ramp. Acceleration target: 200RPM/s. Power was increased at 2000RPM.
Speed ramp will reduce acceleration below the acceleration target (even to negative values) to get back to the desired speed slope.
The acceleration ramp will reduce acceleration back to the desired value, but the theoretical run time will be reduced as a result of the abrupt power increase.
Ramp test demo on MAHA dynamometer converted to DC1 controller. Test is only up to 4000RPM due to speed limiter present in the car.

Sequence

The dynamometer software enables to program engine test sequences that will control engine speed and throttle opening during the test. Test sequence length and number of points is unlimited.

  1. Test sequence mode: engine speed or dyno speed
  2. Speed target area. It is used to control speed limit during the test. If the engine power is sufficient, the speed will follow this curve.
  3. Throttle opening target area. It is used to control throttle opening during the test. More details about throttle control setup can be found on the throttle control page.
  4. Table to edit sequence points. The software guards time values to be monotonic. This means that you can’t enter a bigger time value on the left of a lower time value. You need to increase or delete a value on the right first.
  5. Start sequence button. Pressing the button starts sequence playback.

Keyboard shortcuts used to edit the curves:

  • Del – deletes curve point
  • I – inserts new point to the left of the current one
  • O – inserts new point to the right of current one

Curves can be saved and loaded in files by right-clicking the curve and selecting Save to file / Load from file.

Units and decimal point count can be changed by right-clicking the related axis on the plot and selecting the functions from the context menu.

Outputs control

The output section of the application shows current output state and allows controlling their state.
Output configuration is available by right-clicking the output label.

  1. Output icon
  2. Output label
  3. Control source
    • Manual – the output is activated with a mouse click on the output label. It can be also activated with press of a keyboard button (F1 – F8 from top to bottom). Output state can be monostable or bistable. Monostable output is active only when an activating signal is present (keyboard key or mouse button pressed). It is a good option for controlling starter motor. Bistable output state changes and latches every time it receives an activating signal.
    • Function – the output is controlled with programmable logic function. Functions can be created in SETTINGS / Functions tab.
    • Manual OR Function – the output is active if logic function is active or if it is manually activated. Manual activation can still be monostable or bistable.
    • Manual AND Function – the output is active if logic function is active and if it is manually activated. Manual activation can still be monostable or bistable.
  4. Bistable – check to set manual activation as bistable. Bistable output state is latched every time it receives an activating signal – key press or mouse click.
  5. Off timeout – if this option is activated (value higher than 0s), the output will be switched off timeout time after being switched on manually. This option switches off only the manual part of the (Manual OR/AND Function) logic.
  6. Off argument – if this argument is set, the output will be switched off if the argument has an active value (true). This option switches off only the manual part of the (Manual OR/AND Function) logic.
  7. Function for automatic activation of the output.
  8. Shortcut button to create new function
  9. Shortcut button to edit selected function

The function must have quantity set to “logic” to be available for selection in the output configuration.

Some example configurations are presented below:

Engine starter example. Activated manually. Deactivated after timeout or when engine starts.
Automatic fan activation when the vehicle wheels are rotating.
Lift activation for 5s.

Setting up desktops and available widgets

Dynamometer software configurable user interface
  1. Indicator – shows logic channel state by filling with selected color. It can also be set to indicate channel warning or alarm.
  2. Number – shows data value as numeric value.
  3. Bar – shows data value as color filled bar.
  4. Gauge – shows data value as a gauge with needle pointing the value.
  5. Time Plot – plots data value as a function of time.
    A time based plot shows selected channels as a function of time. On this plot, we can see for example recent speed and power values. Channel selection is made by right-clicking the plot axis to which we want to assign a different channel. Plotting can be paused or cleared during the run. Data retention time can be adjusted with Time history value in widget configuration.
  6. Scatter Plot – plots data value as a function of another value.
    Scatter plot allows analyzing relations between any data channels. These can be for example power and ignition angle. Channel selection is made by right-clicking the plot axis to which we want to assign a different channel. Plotting can be paused or cleared during the run. Data retention time can be adjusted with Time history value in widget configuration.

Widgets through the right click allow access to data channel configuration options.

  1. Hides data channel in selection lists
  2. Text name that is displayed in widgets
  3. Physical quantity that the channel represents
  4. Unit for the value display
  5. Number of decimal places in value display
  6. Channel color
  7. Automatic scale adjustment based on data values
  8. Minimum range span with autorange option
  9. Manual range maximum
  10. Manual range minimum
  11. Threshold to display high alarm information on status bar
  12. Threshold to display high warning indication in widget
  13. Threshold to display low warning indication in widget
  14. Threshold to display low alarm information on status bar
  15. Low pass filter time constant for data display