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Functions of Engine Controls

9/24/2013 12:45:21 PM | by Anonymous

Controls: Engine

Engine controls are commonly known as the power train control module. They are types of control units that control a series of actuators to ensure optimal engine performance. It operates by reading the values from multitudes of sensors within the engine bay followed by interpreting the data using performance maps. Lastly, they adjust the engine actuators accordingly. Before the invention of engine controls, air mixtures, idle speed and ignition timing were set and controlled by mechanical means. Some functions of the engine controls are:


1. Control of Air/Fuel Ratio


The engine control unit determines the quantity of fuel to be injected into engines with fuel injection. It is typically based on the number of parameters. If the throtter position sensor shows the pedal being pressed down, the sensor for mass flow will measure the amount of air being sucked by the engine. The engine control will then inject fixed quantity of fuel into the engine. If the engine temperature sensor shows that the engine has not warmed up yet, more fuel will then be ejected. Computer controlled carburetors works similarly but with a mixture control incorporated in the bowl of the carburetor.


2. Control of Ignition Timing


The ignition timing would require a spark to initiate the combustion in the chamber. The engine control can help to adjust the exact timing of the spark to provide power and economy. If the engine control detects a knock, a condition which destructs engines, and determines that the ignition timing is occurring too early, it will delay the spark to prevent this from happening. Knock tends to occur more at lower room temperatures. The engine control may also send a signal for the transmission as an attempt to alleviate the knock.


3. Control of Idle Speed


Most engines have idle speed being controlled by in built engine controls. They are monitored by the crankshaft sensor which plays the role in the engine timing for fuel injection, valve timing and spark events. Idle speed is being controlled by a throttle stop. Carburetor systems in the earlier days have used a programmable throttle stop using a bidirectional motor. Effective idle speed control must anticipate the engine load during the idle state. Changes occurring during the idle state may come from power steering systems, electrical charging, power braking systems and supply systems. Engine temperature, lift and status of cam shaft can change the load and idle speed. An authority of throttle control system can be used to control the idle speed and provide cruise control functions at the same time.


4. Control of Variable Valve Timing


In some engines, they have variable valve timing. The engine control controls the time in the cycle when the valve opens. The valves usually open at a higher speed. This optimizes the flow of air into the cylinders and increases power at the same time.


5. Electronic Valve Control


Experimental engines have been tested to have no cam shafts. However, they have full electronic controls of the intake and valve openings. These engines can be started without a starter motor for certain engines equipped with timed electronic ignition and injection. The static start would provide efficiency and pollution reduction of a mild hybrid electric drive without the complexity of an oversized motor. Electronic valve operation yields more benefits. They could be made fuel efficient if the intake could be opened on down strokes and exhaust valve opened on up strokes. There are even more advancements which will be the elimination of conventional throttle.

 

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