1. The exhaust system
refers to the collection of the exhaust gas and the system, including an exhaust manifold, an exhaust pipe, the pipe silencer, tailpipe and a resonator.
The exhaust manifold
Display cylinder engine in which two cylinders of an exhaust manifold. Can be seen from the cross section of the left exhaust manifold is directly connected to the vent, and then combined into one. Exhaust manifold design will try to make the same resistance of each cylinder, to allow smooth exhaust. After
of fresh air and fuel mixture into the engine combustion, high temperature high pressure gas pushes the piston, the energy released when the gas, no longer value for the engine, exhaust gases become discharged outside the engine. The exhaust gas is discharged from the rear cylinder, then into the exhaust manifold, the collection manifold of each cylinder, exhaust gas is discharged through the exhaust pipe. As the intake manifold, as is the gas in pulses exiting the engine in the exhaust manifold, the manifold and the length of each cylinder camber also designed as identical as possible, so that the exhaust gas of each cylinder can be the same smooth.
catalytic converter
The main chemical component of the catalyst and effect
The catalyst mainly contains noble metal elements of platinum, rhodium and palladium.
Platinum is a control CO emissions;
rhodium controlling emissions of NO;
palladium controlling emission of HC.
Let’s look at a simple understanding of the composition of engine exhaust gases. Gasoline is a hydrocarbon, almost all carbon and hydrogen atoms in the molecule of gasoline, after combustion of these carbon and hydrogen should be reasonable to produce carbon dioxide (CO2) and water (H2 of (Gallery Forum) O), but because the small amount of mixed gas incompletely burned, and there will be a little oil (unburned but also to burn) is discharged, it will generate HC (hydrocarbon)And CO (carbon monoxide). Further, the intake air into the engine, comprising eighty percent nitrogen (N2 of), but the high temperature of the combustion chamber, the nitrogen had a very stable, will compound with oxygen in the air (the O2), and the production of NO NO2, collectively referred to as NOx. HC, CO and NOx can cause environmental pollution and harmful, so the world will develop environmental regulations, restrictions for vehicle emissions.
Because of environmental regulations on vehicle emissions standards rather harsh, regardless of idling, acceleration, low speed, high speed or slow down, must comply with emission standards, vehicle in the face of such harsh restrictions, in addition to performance to strike a balance in the sewage, the only “Piebu” is the catalytic converter. Catalytic converters typically precious metals as raw material, oxidation catalyst, reduction catalyst and the vast majority of vehicles with catalytic converters.
After the exhaust manifold, catalytic converter will connect to the incomplete combustion of pollutants converted to innocuous substances, the protection of the environment.
again on simple chemical class, HC and CO emissions because of incomplete combustion are generated, they must be re-combustion eliminate them, i.e. to make them to oxidation, which is oxidized task catalyst. And it is because the generation of NOx due to oxidation of the nitrogen, it is necessary to further reduce NOx reduction catalyst to nitrogen gas. Three-way catalytic converter is to allow reduction of NOx and oxidation of CO and HC occur on the same catalyst. The catalyst itself is not involved in the oxidation or reduction of a chemical reaction, it is just a catalyst in chemical reactions.
catalytic converter where it is located? Early multiple catalytic converter exhaust pipe provided at a position in the middle, and the more recently installed immediately after the exhaust manifold, a catalyst to accelerate the Haoshi reach operating temperature. The catalyst must be at near 500-degree heat, to get a better conversion efficiency is almost no conversion capability at low temperatures, so the cold car emissions is considerable. So this should remind all owners, do not heat indoors or underground parking car, try to launch a car to open to the outside, they are not to poison themselves or other persons in a car park.
muffler
Even coming out from the catalytic converter to the muffler, the muffler is a circular cross-sectionOr elliptical object, the use of welded steel sheet, mounted in the middle or rear position on the exhaust system, which has a series of baffles inside the chamber, and piping hole, with acoustic waves reflected interference phenomenon cancel each other, so that gradually weaken acoustic energy to pressure pulsations generated when exhaust valve each time the isolation and decay opened.
As the name implies, is used to eliminate noise muffler of the exhaust gas, so that the vehicle travels up quieter. Usually there will be a number of muffler expansion chambers, an exhaust gas discharged from the engine after the expansion program number, so that the exhaust pulses will alleviate and eliminate noise. However, since the gas in the muffler complex path, i.e. in other words the reduced smoothness of the muffler of the exhaust gas, it will also slightly affect engine performance. Some people will modify their own straight-through exhaust tail pipe, so although slightly enhance engine performance, but it will greatly increase the exhaust noise, so it was not worth it and certainly violate traffic regulations behavior.