Engine¶

Engine Layout

The Engine component configures the internal combustion engine (ICE) power source. It is only visible when the Power Source Type is set to Internal Combustion Engine on the Powertrain Overview.

The Engine is an independent library component — it can be saved, loaded, duplicated, and shared separately from the parent Powertrain.

Parameters¶

The Engine section contains two rows of parameters:

RPM Limits¶

Parameter	Description	Default	Unit
Minimum Engine Speed Limit	The lowest RPM the engine can operate at. Defines the lower bound of the operating range.	0	RPM
Maximum Engine Speed Limit	The highest RPM the engine can reach. Limits engine speed and defines the upper bound for gear shift calculations.	10,000	RPM

Max RPM must be greater than min RPM.

Torque Curves¶

Both curves are defined as 1D Maps (RPM vs Torque). Click the map thumbnail to open the editor.

Parameter	Description	X-Axis	Y-Axis
Engine Torque Curve	The positive torque output at each RPM point. This is the primary performance curve of the engine.	RPM	Torque (Nm)
Engine Braking Curve	The negative torque (engine braking / back-torque) at each RPM point. Optional — if not provided, engine braking is zero.	RPM	Braking Torque (Nm)

Engine Braking

The engine braking curve represents drag torque when the driver is off-throttle (e.g., compression braking). Values should be negative or zero. If not configured, the simulation assumes no engine braking effect.

How Engine Torque is Used¶

The engine provides a base torque at a given RPM. This torque flows through the drivetrain:

Engine Torque (at RPM)
    → × Efficiency (if enabled)
    → × Gear Ratio × Final Drive × Bevel Ratio
    → Wheel Torque

The simulation determines the operating RPM from vehicle speed, gear ratio, final drive, bevel ratio, and rolling radius:

Engine RPM = Vehicle Speed × (Gear Ratio × Final Drive × Bevel Ratio) / Rolling Radius × (60 / 2π)

The RPM is clamped between the min and max RPM limits. Outside this range, the engine cannot produce torque.

Power Curve¶

The platform automatically derives the power curve from the torque curve:

Power = Torque × RPM × (2π / 60)

This is used internally for peak power calculations and is not directly editable.

Validation Warnings¶

Condition	Warning
Operating range < 3,000 RPM	Narrow range may limit performance
Operating range > 10,000 RPM	Very wide range — verify specifications
Torque curve variation < 20%	Unusually flat torque curve — check engine data
Max RPM < 2× min RPM	Narrow RPM spread may limit performance
Min RPM below lowest torque map RPM	Min RPM extends below the defined torque data

Tips¶

Start with the torque curve — this is the most important parameter. If you have dyno data, enter the RPM and torque columns directly using the map editor (paste from Excel or Google Sheets)
Set RPM limits to match your data — the min and max RPM should align with the range of your torque curve. If the min RPM is below the lowest torque map point, the simulation will extrapolate
Engine braking is optional — for most lap time simulations, omitting it is acceptable. It becomes more relevant for transient simulations where off-throttle behaviour matters
The engine is shared across setups — since it's an independent library item, changing it will affect all powertrains that reference the same engine

Next Steps¶

Configure Gears for transmission ratios and shift strategy
Configure Efficiency for drivetrain loss modelling
Return to Powertrain Overview for the full system architecture