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EspañolMANIFOLD (AUTOMOTIVE ENGINEERING)
(Redirected from Intake manifold)
In automotive engineering, an 'intake manifold' or 'inlet manifold' is a part of an engine that supplies the fuel/air mixture to the cylinders. An 'exhaust manifold' or 'header' collects the exhaust gases from multiple cylinders into one pipe.
The word ''manifold'' may come from the Old English word ''manigfeald'' (from the Anglo-Saxon ''manig'' [many] and ''feald'' [fold]) and refers to the folding together of multiple inputs and outputs. Alternatively, it may come from the Latin ''mano'' (hand) and simply means "hand-shaped".
Due to the suction effect of the downward movement of the pistons in a reciprocating piston engine, a partial vacuum (lower than atmospheric pressure) exists in the intake manifold. If the engine has a throttle valve (i.e. in spark ignition rather than diesel engines) this manifold vacuum can be substantial, and can be used as a source of automobile ancillary power to drive auxiliary systems: (ignition advance, power assisted brakes, cruise control, windshield wipers, power windows, ventilation system valves, etc).
This vacuum can also be used to 'suck' any piston blow-by gases from the engine's crankcase. This is known as a ''closed crankcase ventilation'' or ''positive crankcase ventilation'' ('PCV') system. This way the gases are burned with the fuel/air mixture.
The intake manifold is usually made of aluminium but there are some cases where it is made of plastic (Most Chrysler 4 cylinders and duratec 2.0 and 2.3 on Ford Focus and Mazda3) and located between the carburetor and the cylinder head. On multi point injected engines, the intake manifold holds the fuel injectors.
Exhaust manifolds can crack due to the high heat they are under if water drips on them. If an exhaust manifold is replaced and soon after the replacement cracks, it may be due to a constant leak of cold water dripping onto the cast iron.
Exhaust manifolds are generally and traditionally simple cast iron units which collect engine exhaust and deliver it to the exhaust pipe. However, when greater performance is required, this restrictive tube is often replaced with individual 'headers' (also known as 'extractors' in Australia) which are tuned for low restriction and improved performance. There are two types of headers. Collector style headers use pipes that merge into a collector, and can be utilized with mufflers. Collector headers can be used for the street or for a race car. Zoomie headers have no collectors, and are used exclusively on race cars. Headers have been widely available from aftermarket sources for decades, and some manufacturers have begun using them as original equipment. The Honda ''J30A2'' engine does away with exhaust manifolds altogether, using an integral engine block passage to route gases directly to the catalytic converter.
★ engine tuning
In automotive engineering, an 'intake manifold' or 'inlet manifold' is a part of an engine that supplies the fuel/air mixture to the cylinders. An 'exhaust manifold' or 'header' collects the exhaust gases from multiple cylinders into one pipe.
The word ''manifold'' may come from the Old English word ''manigfeald'' (from the Anglo-Saxon ''manig'' [many] and ''feald'' [fold]) and refers to the folding together of multiple inputs and outputs. Alternatively, it may come from the Latin ''mano'' (hand) and simply means "hand-shaped".
Due to the suction effect of the downward movement of the pistons in a reciprocating piston engine, a partial vacuum (lower than atmospheric pressure) exists in the intake manifold. If the engine has a throttle valve (i.e. in spark ignition rather than diesel engines) this manifold vacuum can be substantial, and can be used as a source of automobile ancillary power to drive auxiliary systems: (ignition advance, power assisted brakes, cruise control, windshield wipers, power windows, ventilation system valves, etc).
This vacuum can also be used to 'suck' any piston blow-by gases from the engine's crankcase. This is known as a ''closed crankcase ventilation'' or ''positive crankcase ventilation'' ('PCV') system. This way the gases are burned with the fuel/air mixture.
The intake manifold is usually made of aluminium but there are some cases where it is made of plastic (Most Chrysler 4 cylinders and duratec 2.0 and 2.3 on Ford Focus and Mazda3) and located between the carburetor and the cylinder head. On multi point injected engines, the intake manifold holds the fuel injectors.
Exhaust manifolds can crack due to the high heat they are under if water drips on them. If an exhaust manifold is replaced and soon after the replacement cracks, it may be due to a constant leak of cold water dripping onto the cast iron.
Exhaust manifolds are generally and traditionally simple cast iron units which collect engine exhaust and deliver it to the exhaust pipe. However, when greater performance is required, this restrictive tube is often replaced with individual 'headers' (also known as 'extractors' in Australia) which are tuned for low restriction and improved performance. There are two types of headers. Collector style headers use pipes that merge into a collector, and can be utilized with mufflers. Collector headers can be used for the street or for a race car. Zoomie headers have no collectors, and are used exclusively on race cars. Headers have been widely available from aftermarket sources for decades, and some manufacturers have begun using them as original equipment. The Honda ''J30A2'' engine does away with exhaust manifolds altogether, using an integral engine block passage to route gases directly to the catalytic converter.
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★ engine tuning
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