Generic Engine

By default, the block Generic Engine Uses a pre-programmed ratio between torque and rotational speed, which is modulated by a throttle signal or a torque control signal.

The unit evaluates the required engine power as a function of the engine speed . The function calculates the maximum power available for a given engine speed. . Block Parameters Maximum power, Speed at maximum power and Maximum speed This function is normalized relative to the physical values of maximum torque and rotational speed.

Normalized throttle signal regulates engine power in such a way that . When selecting a value Normalized throttle for the parameter Model parameterization The physical input signal Thr controls the power of the motor. When selecting a value Torque command The unit calculates the value of the normalized throttle signal automatically. The unit outputs power equal to a fraction of the maximum possible power in steady-state mode at a fixed engine speed.

If for the parameter Model parameterization the value is set Normalized 3rd-order polynomial, the unit uses a normalized engine speed to calculate the rotation speed and torque. The block defines the normalized engine speed as

where

The block processes the normalized dimensionless engine power as a third-order polynomial such that

where , and — constant polynomial coefficients, — peak power. In typical engines, the coefficients are they are positive.

The unit calculates the engine torque with the throttle fully open using polynomial coefficients such that

The unit sets the normalized engine speed at peak power in such a way that

Substituting this equality into the formula for gives

This condition normalizes the power relative to the engine speed at peak power. The unit sets the slope equal to zero, so that

The block defines the normalized engine speed with peak torque as

where the speed of reaching peak power is greater than the speed of reaching peak torque. The block uses a polynomial formula to find the dimensionless normalized torque. and sets the tilt angle to zero in such a way that

The solution for using these equations gives

The unit calculates the engine torque as follows

where — peak torque. Substituting the equation for gives a restriction

The block uses , and to calculate the engine speed at peak power so that

where equivalent to power at peak torque , which is always less than the peak power .

Engine power forms for different types of engines

The block calculates the polynomial using the corresponding coefficients specified in the parameter Engine type. When selecting values Spark-ignition or Diesel for the parameter Engine type The block selects the appropriate coefficients from the table. When selecting a value Generic The block calculates these coefficients independently.

The unit can additionally simulate fuel consumption and output the results as a physical signal to the FC port. To include fuel consumption in the simulation, set the parameter Fuel consumption model one of the following values:

The idle speed control adjusts the throttle signal to increase the engine speed below the reference speed in accordance with

and

where

The controlled throttle increases with a first-order delay from 0 before 1 when the engine speed drops below the reference speed. When the engine speed exceeds the reference speed, the adjustable throttle decreases from one to zero. When the difference between the engine speed and the reference speed is less than the speed threshold set by the regulator, the tangential component of the equation smooths out the time derivative of the controlled throttle. The smoothing function limits the adjustable throttle to a range of [0,1]. The motor uses the larger of two values: input and adjustable. If the engine delay is enabled, the controller will change the input data before calculating the delay.

The idle speed control determines the minimum throttle opening value to maintain engine speed, and the red zone control prevents exceeding the permissible speed based on the maximum throttle opening value. To determine the maximum throttle opening value, the red zone controller uses the equation of the idle speed controller model. However, for the red zone regulator:

To increase the simulation speed, set the parameter Fuel consumption model meaning No fuel consumption. When using this setting, the unit does not calculate fuel consumption regardless of the FC port.

If any other value is selected for the parameter Fuel consumption model, the block must perform a non-linear calculation. The unit solves the equation even if the FC port that reports fuel consumption is not connected to another unit.

Engines respond with delay to changes in throttle speed and position. The unit maintains a delay only due to a change in the throttle position.

The table shows how the parameter values are Fuel consumption model they affect the availability of dependent parameters.