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Vacuum Modulator is an engine load sensing device that converts engine vacuum into a transmission valve body input.. Most vacuum modulators operate with manifold vacuum (below throttle blades) that offer more vacuum at idle, and proportionately changes (rises and falls) with engine load as opposed to operating on engine speed.
The goal of EGR is thus to reduce NO x production by reducing the combustion temperatures. In modern diesel engines, the EGR gas is usually cooled with a heat exchanger to allow the introduction of a greater mass of recirculated gas. However, uncooled EGR designs do exist; these are often referred to as hot-gas recirculation (HGR).
A vacuum delay valve is a valve with a small orifice, which delays a vacuum signal. These are commonly used in automobiles to alter the behavior of vacuum switches, ...
The intake manifold vacuum, with wide open throttle, is lower in these conditions, which causes the PCV valve to open and the crankcase gases flow to the intake system. [13] The greater flow rate of intake air during these conditions means that a greater quantity of blow-by gases can be added to the intake system without compromising the ...
The MAP sensor is then used for rationality checks and to test the EGR valve. The way they do this is during a deceleration of the vehicle when there is low absolute pressure in the intake manifold (i.e., a high vacuum present in the intake manifold relative to the outside air) the powertrain control module (PCM) will open the EGR valve and ...
After 1997 the diesel edition received an EGR system, which came with a plastic inlet manifold. A modulator sends back part of the exhaust gas into the manifold, thus mixing hot exhaust gas via a vacuum pump into the cold air from the intercooler. Post 97 cars also utilised a MAF sensor for better economy and cleaner running.
Manifold vacuum, or engine vacuum in a petrol engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere. Manifold vacuum is an effect of a piston's movement on the induction stroke and the airflow through a throttle in the intervening carburetor or throttle body leading to the intake manifold. It is a ...
The vacuum flowed through the switch to a vacuum solenoid (such as a heat riser, used to restrict exhaust allowing the engine to heat up faster). When the coolant heated to operating temperature the vacuum switch closed off the port (port S on the vacuum switch) turning off the vacuum to the heat riser. The result is to clear the exhaust ...