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List of contents of this article:

• 1, What is mechanical efficiency? When the speed, load, oil viscosity and water temperature of the engine change, η...
• 2, The higher the speed, the greater the load, the higher the mechanical efficiency of the engine High
• 3, What is mechanical efficiency fv?
• 4 、Mechanical Efficiency of Passenger Jet Engine

What is mechanical efficiency? When the speed, load, oil viscosity and water temperature of the engine change, η...

Mechanical efficiency refers to the transmission efficiency of the engine movement. Thermal efficiency refers to the ratio of the energy effectively used after the combustion of engine fuel to the total energy released by fuel combustion. When the engine is running, the combustion is insufficient, and the mechanical efficiency is not necessarily reduced.

The engine speed is constant, and when the load increases, the mechanical efficiency of the engine increases.(Right) 1 The greater the viscosity of the oil, the smaller the mechanical loss of the engine (wrong, the greater the friction) 1 The intake temperature increases, and the inflation efficiency increases.

c. Combustion loss: non-instaneous combustion loss and supplementary combustion loss; incomplete combustion loss; chemical dynamic balance, high-temperature thermal decomposition, need to absorb heat; heat transfer loss (the work quality has heat exchange with the cylinder head, cylinder wall, piston, etc.); in-cylinder flow loss (eddy current and turbulent will cause resistance and consume more work).

The engine speed is constant. When the load increases, the inflation efficiency of the gasoline engine ( ) and the inflation efficiency of the diesel engine ( ). The engine speed is constant, and when the load increases, the average mechanical loss of pressure ( ) and mechanical efficiency of the engine ( ). The position of the engine throttle remains unchanged. When the speed increases, the average mechanical loss pressure of the engine ( ) and the mechanical efficiency ( ).

Thermotulator: Thermoder is the most important cooling intensity adjustment device on the engine. Its function is to automatically change the flow and circulation route of the coolant according to the size of the engine load and water temperature to ensure that the engine works at the appropriate temperature.

The higher the speed, the greater the load, the higher the mechanical efficiency of the engine

The ordinary four-stroke gasoline engine is only 20%~40%, the diesel engine is higher, the rotor engine has higher mechanical efficiency, super If it is over 60%, if you install a turbojet engine, it will be very efficient.

Yes, the power and torque increase in proportion to the speed. P=F×V. It's just like this for the engine. ConnectWith the gearbox, the output power is also the same. The gearbox just changes the speed and torque.

Mechanical efficiency: the degree to which the work is transformed into an effective work. Load must = Pi.Ni is basically unchanged n↑=friction loss↑=mechanical loss↑=Pm↑ get: n↑, ηm↓. When the speed of the engine changes, the drag moment acting on the crankshaft of the engine. N is unchanged, Ne∝Me, Ne∝Pe, so the load can be represented by Ne, Pe.

High speed will affect fuel consumption. Of course, high engine speed will consume more fuel, but the fuel consumption problem can be improved by reasonably controlling the speed, because the van itself has a large wind resistance coefficient, and the light air resistance at high speed is greater than that of the car. In addition, the engine speed is very high, and the fuel consumption cannot be reduced.

But it is not absolute, because there is still a problem of thermal efficiency in the engine, and thermal efficiency is the key, that is to say, how much the calorific value of the oil finally turns into mechanical output. However, the higher the speed, the shorter the engine ventilation and exhaust time, and the more incomplete the combustion. Therefore, large internal combustion engines adopt low-speed engines to improve thermal efficiency.

What is the mechanical efficiency fv equal to

Calculation of mechanical efficiency Lever: η=W useful ÷ W total =Gh÷FS where G is the gravity of the lifting heavy object, h is the height of the lifting of the heavy object, F is the power, and s is the distance of movement of the force action.

He asked about the power of the free pull end, so he must use the power formula P=Fv about the pull. Note that the speed v is the speed at which the object moves, and the speed at the free end of the rope is: the number of rope segments connected to the moving pulley * the speed of the object.

Funally different physical quantities: power is the speed of the work done, that is, how much work is done in 1s, the unit is W (watt) or kw, the calculation formula is P=W/t, and W is the work. Efficiency is the ratio of useful work to total work, which is a percentage. Because of the existence of extra work, the efficiency is always less than 1.Unknown inquiry.

The calculation formula is: W total = W has + W amount or W total = Fs (s is the distance of the free end of the rope) The calculation of mechanical efficiency. General calculation formula: η=W has / W total = Gh/Fs=G/Fn (n is the number of rope segments that bears the moving pulley.

Mechanical efficiency of passenger jet engine

1. The jet engine of the aircraft uses a compressor to suck in air, and then push the aircraft through high-speed injection fuel and air mixture. The mechanical efficiency of this engine can reach 60%, so the energy consumption utilization rate of the aircraft is relatively high.

2. The thermal efficiency of turbojet engines is generally 24%~30%. Folding propulsion effectRate: The ratio of the propulsion power of the engine (or thruster) to the effective power is called propulsion efficiency (flight efficiency), which is used to evaluate the effectiveness of the thruster.

3. The actual practical speed of jet aircraft is 150 meters/s to 800 meters/s. Only at an altitude of 10,000 meters to 15,000 meters can the best propulsion efficiency be achieved. A jet aircraft is an aircraft that uses a jet engine as a source of propulsion.

4. The maximum power that an aircraft jet engine can produce is 110000kW. According to the relevant public information of the query, the engine power of the jet aircraft is about 110,000 kilowatts, which means that the engine does 110,000,000 joles of work per second, that is, the chemical energy of 110,000,000 joules per second is converted into the kinetic energy and potential energy of the aircraft.

5. Jet engine. The structure of modern turbojet engines is composed of intake duct, compressor, combustion chamber, turbine and tail nozzle. There is also a forced combustion chamber between the turbine and tail nozzle of the fighter.