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🚗 | BMW X5 / X6 / X7 diesel model with 48V mild hybrid

Photo BMW X6

BMW X5 / X6 / X7 diesel model, equipped with 48V mild hybrid

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Depending on the model, the fuel consumption rate is improved by up to 1.1km / liter in WLTC mode.

BMW Japan (BMW Japan) will release "X2", "X24", "X5" clean diese on February 6th ... → Continue reading


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Fuel consumption rate

Fuel consumption rate(Nenryo Shohiritsu,British: Specific Fuel Consumption, SFC) IsHeat engineAn indicator of the efficiency of.The unit is g / PS ï½¥ h or g / kW ï½¥ h.

Turbojet and turbofan engine

Jet engineThen.thrustEspecially because it targetsthrust specific fuel cIt is called onsumption "(tsfc). The fuel consumption (kg / h) consumed during continuous operation for 1 hour at the rated thrust is divided by the rated thrust (kgf), and the unit is kg / (kgf · h). The engine maker istake offTime andcruiseIt often presents two types of rated thrust.Takeoff tsfc is useful for comparison with other engines because it is not affected by the performance of the aircraft equipped with that engine, and cruising tsfc is more important for users such as airlines.However, when cruising, tsfc isheightAnd flightMach numberIt also changes depending on cruising conditions such as.

Turboprop engine and turboshaft engine

There are the following two display methods.Turboprop engine,Turbo shaft engineThen, since the engine maker and the propeller (rotor) maker are separate, the propeller propulsion efficiency is not considered.


Fuel consumption during 1-hour rated operation (LB / H or kg / h)horsepower Value divided by (shp, shaft horse power).The unit is LB / (shp · h) or kg / (shp · h).


With a turboprop engine, the exhaust toward the rear also has a jet effect.This thrust is converted into horsepower based on the flight conditions at that time, and the converted horsepower (ehp, equivalent shaft horsepower) added to the shaft output is calculated using the above shaft output instead.The unit is kg / (ehp · h).Generally, esfc is 5 to 10% lower than sfc, but it changes because the flight condition factor is added to the conversion of exhaust jet thrust.This esfc is not used in turboshaft engines.

Rocket engine

rocketIn the case of, it is the time (seconds) to keep producing 1 kgf of thrust with 1 kg of fuel.Specific thrustIt is represented by.Therefore, the larger the rocket, the better the performance of the rocket.The SFC of the aircraft engine is the SFC of the rocket.ReciprocalNote that the number is multiplied by 3,600.

SI unitThen 1 N The amount of fuel (kg) consumed to keep producing the thrust of is defined as the fuel consumption rate, so in the case of a rocket, it is the reciprocal of SFC in an aircraft engine multiplied by 1.At the aircraft engine site, SI units are not often used except for the description in the paper.


  • Tsukasa Yoshinaka, "The Story of a Jet Engine That Does Not Use Formulas," Sotosha, 1990.


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