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Resize the SI Engine

By default, the spark-ignition (SI) engine dynamometer reference application engine is configured with a turbocharged 1.5-L dynamic gasoline engine. Based on a desired number of cylinders and maximum engine power or engine displacement, you can resize the dynamic engine variant for different vehicle applications.

You can use the Virtual Vehicle Composer app to resize your virtual vehicle engine based on desired maximum engine power or engine displacement. For more information, see Resize Engines and Mapped Motors.

To resize the engine, use the dynamometer reference application. After you open the reference application, click Resize Engine and Recalibrate Controller. In the dialog box, set Resize option to either:

  • Power – Enter a Desired maximum power value.

  • Displacement – Enter a Desired displacement value.

For either power or displacement, enter a Desired number of cylinders value.

When in Displacement mode, you can define the maximum torque and the engine speed at which maximum torque occurs. Click the checkboxes to enable these entry fields.

You can choose the architecture, air path configuration (turbocharged or naturally aspirated), and presence or absence of cooled exhaust gas re-circulation (EGR) of your engine model. After making your selections, click Resize Engine to set the engine variant.

The available engine variants are:

Engine SubsystemVariantDescription
Engine

SiEngineCore (default)

Dynamic Inline Turbo SI Core Engine

SiEngineCoreNA

Dynamic SI Inline Naturally Aspirated Engine

SiEngineCoreV

Dynamic SI V Twin-Turbo Single-Intake Engine

SiEngineCoreVNA

Dynamic SI V Naturally Aspirated Engine

SiEngineCoreVThr2

Dynamic SI V Twin-Turbo Twin-Intake Engine

After you apply the changes, the reference application:

  • Resizes the dynamic engine and engine calibration parameters. The Resize Engine and Recalibrate Controller block mask provides the updated engine performance characteristics based on the resized calibration parameters.

  • Recalibrates the controller and mapped engine model to match the resized dynamic engine.

You can use the variants in other applications, for example, in vehicle projects that require a larger engine model.

Create SI Engine Models with Twice the Power

  1. If it is not already open, open a copy of the SI engine reference application project by entering

    autoblkSIDynamometerStart

  2. In the SiDynoReferenceApplication model window, click Recalibrate Controller.

    The reference application performs a dynamometer test to calibrate the engine controller for the default 1.5-L dynamic engine. For engine speeds 2000–5000 rpm, the measured engine torque approaches 220 N·m. The steady-state results for measured engine torque as a function of torque command and engine speed are similar to this plot.

  3. In the SiDynoReferenceApplication model window, click Resize Engine and Recalibrate Controller. The dialog box provides the calibration parameters for the current engine design, the default 1.5-L dynamic engine.

  4. In the Resize Engine and Recalibrate Controller dialog box, on the Design tab, set the resize options and engine architecture that represent twice the maximum power and number of cylinders. For example, set:

    • Resize option to Power.

    • Desired maximum power to 230.

    • Desired number of cylinders to 8.

    • Architecture to V.

  5. Click Resize Engine. The reference application:

    • Resizes the dynamic engine (SiEngineCore) and engine calibration parameters. The Recalibrate Engine dialog box provides the updated engine performance characteristics based on the resized calibration parameters.

    • Recalibrates the controller (SiEngineController) and mapped engine model (SiMappedEngine) to match the resized dynamic engine (SiEngineCore).

    After resizing and recalibration, the dialog box provides the calibration parameters for the resized engine. The parameters are similar to these.

  6. Examine the dynamometer steady-state results. For engine speeds 2000–5000 rpm, the measured engine torque approaches 450 N·m. This result is approximately twice the power of the default dynamic engine. The steady-state results for measured engine torque as a function of torque command and engine speed are similar to this plot.

  7. To save the engine controller, resized engine mapped variant, and resized dynamic engine variant, in the SiDynoReferenceApplication model window, save the reference application.

By default, this process creates:

  • An updated SI engine controller

  • Two engine variants — mapped and dynamic

To see the parameters associated with the controller and engine variants:

  1. In MATLAB®, use the Project Shortcuts tab to open these models:

    • SiEngineController

    • SiEngineCore

    • SiMappedEngine

  2. Use the Model Explorer to view the resized parameters:

    Engine ModelModel Explorer

    Controller — SiEngineController

    Mapped — SiMappedEngine

    Dynamic — SiEngineCore

  3. In the SiDynoReferencApplication > Engine System > Engine Plant > Engine > SIMappedEngine subsystem, open the Mapped SI Engine block. On the Power tab, plot the actual torque as a function of engine speed and commanded torque.

See Also

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