Brake Mean Effective Pressure (Bmep) SI Engine

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SUMMARY

The discussion centers on the use of Torque max. versus Power max. in the Brake Mean Effective Pressure (BMEP) equation for SI engines. It is established that one cannot substitute torque for power in the BMEP calculation due to the inherent relationship between torque, engine RPM, and power output. The calculations presented indicate that the BMEP at maximum Brake Power is approximately 210 times greater than that at maximum Torque, which raises questions about the validity of such a disparity.

PREREQUISITES
  • Understanding of Brake Mean Effective Pressure (BMEP) calculations
  • Knowledge of the relationship between torque, power, and engine RPM
  • Familiarity with SI engine performance metrics
  • Basic principles of thermodynamics as applied to engine cycles
NEXT STEPS
  • Study the equations relating torque, power, and RPM in SI engines
  • Research the implications of BMEP on engine performance and efficiency
  • Examine case studies of BMEP calculations in various engine configurations
  • Explore advanced thermodynamic principles relevant to engine design
USEFUL FOR

Engineers, automotive performance specialists, and students studying internal combustion engine dynamics will benefit from this discussion.

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Dear all,

Can Torque max. be used instead of Power max. in the bmep equation?-(as shown on attached pic)

The name of the equation seems to suggest it is only for Brake Power but hopefully i am wrong.

Also, when I do a calculation for bmep for max. Brake Power and max. Torque, the bmep at max. Brake Power is about 210 times that for bmep at max. Torque (Shown in attached picture):
Can this be correct?

Thanks for reading

307MED 2011 Q1a i) 001.jpg

 
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You can't just blindly plug in torque in place of power in the equation for BMEP.

Remember, there is a relationship between torque, engine RPM and power output.
 
Yes I have found that equation as well, thank you. Need stronger knowledge of basics as always
 

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