The governor consists of goveror balls, sleeve, spring( inertial governor) and arms. It is conected to the Power output of the engine to regulate the speed over a period of cycles. Since governor these many parts and as they are attached to the output shaft, those (parts of governor) weight gets added to the shaft which may cause deflection of shaft or decrease in Power output (due to action of load).
If it decreases the powe routput, it will try to decrease the efficiency of the engine. Am I right ?....
I guess it depends how this governor works.
Let's say you design a wasteful, mechanical governor. The rapidly turning driveshaft opens up weighted arms, which engage a shaft brake at a certain shaft speed (or even the regular car brakes). Engine power would not decrease, in that case. The engine will try to fight the governor, creating a lot of heat in the process. Power to the wheels will be taken away, but the engine will be straining to overcome the brakes. So, engine operating at high efficiency, to "efficiently" generate heat from the braking surfaces.
A better way is to have the governor feed its signal back to the fuel supply to the engine. In this case, clearly as fuel is blocked from reaching the engine, the engine's torque will be removed, hence power will be decreased. Yes, engine "efficiency" will go down, but you'll be saving energy.
If efficiency is measured as power output for a given amount of fuel input, then fuel saving techniques, including reducing rolling resistance and aerodynamic drag, will just about always result in operating the engine at lower efficiency.
The governors main purpose in engines is to limit the maximum speed of the engine to protect engine from breakdown and low idling speed to protect engine from stalling when loaded. The governors does this activity by controlling the fuel to the engine. Hence generally, governors are integral part of fuel supply system. In case of conventional diesel engine, governor is an integral part of fuel injection pump. Based on type of applications, there are two types of mechanical governors used in diesel engines - Two speed governor, which is mainly used in passenger vehicle applications and controls only low and high idling rpm of the engine and the other one is All sped governor, which is mainly used in off-road applications which governs the fueling throughout the the entire range of engine speed. However with recent advances in engine management systems, the mechanical governor is almost useless as ECU takes control of everything.
Moreover the governor that you have seen in your laboratory are just devices to explain the concept of governing. However the actual one that is used in diesel engine is way smaller than your imagination. Nonetheless, it will have all essential components mentioned by you.
To answer your question regarding efficiency, yes the fuel injection pump consumes lot of power from the engine, but the power required to pressurize the fuel to high pressures for injection is way higher than the power used by the governor weights.So the efficiency of the engine does not change much with use of governor weights. And in modern engines the governor weights are no more useful as it is ECU controlled.
The new concept thatI have been exposed by you is ECU......Can you please provide me referance links that make me to learn about that? @ balaji mohan
ECU is an Electronic Control Unit or Engine Control Unit which uses actuators to control air/fuel ratio of an Engine.
With the advent of technology and control systems lot of developments have taken place in the automatic control of many machines. The increased power of computation and cheap availability of memory has drastically changed how systems are controlled.
The ECU works on a feedback given by the Engine(Sensors if stated correctly) it controls the actuators according to the values of sensors. Actuators can be servos, fluid hydraulic actuators anything that can regulate the flow of fuel.
If you want to know more about how ECU works and how it can be designed the best thing you can do is to learn "Control Theory".
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