Calculating AFR and engine load

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SUMMARY

The ECU calculates engine load based on various parameters, including the engine's current operating conditions and its maximum potential load. The air-fuel ratio (AFR) is determined using Mass Air Flow (MAF) and oxygen (O2) sensor readings. By analyzing these values, it is possible to estimate the fuel consumption in grams per second (g/s) and subsequently calculate the engine's power output by considering the heat energy released during combustion. This process involves subtracting the exhaust heat flow from the total heat energy generated in the cylinder.

PREREQUISITES
  • Understanding of Engine Control Units (ECUs)
  • Knowledge of Mass Air Flow (MAF) sensors
  • Familiarity with oxygen (O2) sensor functionality
  • Basic principles of thermodynamics related to combustion
NEXT STEPS
  • Research how to interpret MAF and O2 sensor data for engine diagnostics
  • Learn about calculating engine power output using thermodynamic principles
  • Explore advanced ECU tuning techniques for optimizing AFR
  • Investigate methods for measuring exhaust heat flow in automotive applications
USEFUL FOR

Automotive engineers, ECU tuners, and anyone involved in performance optimization of internal combustion engines will benefit from this discussion.

silver123
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Hi,

can someone tell me how the ECU calculates the engine load (this value isn't measured directly). All I found about engine load is that this is the value that tells us how much load an engine is overcoming in the dependence of how much load it could overcome at the momentarly circumstances.

the other thing that I woul like to know is how the ECU determine air to fuel ratio. All I konw is that it uses MAF and O2 readings.
But can we calculate how much fuel (g/s) was burned in a cylinder by reading these values (MAF and O2)? If we know that mass flow (g/s) and fuel heat energy (39MJ/kg for gasoline I think), we could calculate how much power engine is producing by subtract the exhaust heat flow from release heat energy in a cylinder. We can easily calculate exhaust heat flow, by knowing air and fuel flow and temperature difference between intake and exhaust gases.
 
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what isn't this physics forum, thought this question will be a piece of cake for you:frown:
 
**** off all off you, Why you have physics forum if no one can answer a simple question!
 

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