Fuel & Injector Model

Applies to: IOcan · Standalone controller. What this means

The fuel-based torque estimation methods (Fuel + Air (arbitrated), Fuel Model, and the air model in Air Model) work out how much fuel the engine is burning from the ECU's injector signal. For that, each driver carries the same injector model, configured once per injector set.

Primary and secondary injector

There are two injector sets with identical settings:

  • The primary set is active as soon as its Injector pulse width input is assigned. It is required by every fuel/air method.
  • The secondary set is optional — assign its pulse-width input only for staged or auxiliary injection.

Settings

Setting Meaning Unit
Fuel type Selects the built-in fuel data — see below Gasoline · Flex Fuel · Ethanol 100 · Ethanol 85 · Methanol · Diesel · User defined
Injector pulse width Live injection-time signal from the ECU µs
Injector size Static flow rating of one injector cm³/min
Nominal injector pressure Pressure the flow rating applies at kPa
Deadtime mode How injector dead time is obtained — see below Do not use · Input · User defined
Deadtime input Live dead-time signal (mode Input) µs
Fuel pressure Live fuel-pressure input — enables pressure compensation kPa
Fuel temperature Live fuel-temperature input — refines fuel density °C
Flex Fuel Live ethanol-content input (fuel type Flex Fuel) %

Fuel types and built-in fuel data

For every fuel type except User defined, the fuel's density, stoichiometric AFR and energy content are built into the firmware — you do not fill any fuel tables. The ethanol content is also implied by the type; only Flex Fuel reads the live Flex Fuel input:

Fuel type Fuel data Ethanol content
Gasoline built-in fixed (E5 pump fuel)
Ethanol 85 built-in fixed 85 %
Ethanol 100 built-in fixed 100 %
Flex Fuel built-in from the Flex Fuel input
Methanol built-in —
Diesel built-in —
User defined from your fuel tables from the Flex Fuel input

With User defined, fill the three fuel tables:

Table Axes Calibrates
Fuel density Ethanol % × temperature Density of the blend
Stoichiometric AFR Ethanol % (1D) Stoich air-fuel ratio of the blend
Fuel energy Ethanol % (1D) Energy content of the blend

Dead time

Injector dead time (the opening delay that burns no fuel) is subtracted from the pulse width before the fuel mass is calculated:

  • Do not use — pulse width is taken as-is.
  • Input — dead time comes from the live Deadtime input (e.g. the ECU broadcasts it).
  • User defined — dead time is looked up from the Deadtime table (axes: battery voltage × fuel pressure).

Fuel-pressure compensation

When the Fuel pressure input is assigned and a Nominal injector pressure is set, the effective injector flow is corrected for the actual rail pressure. Leave the input unassigned to always use the rated flow.