SCR (selective catalytic reduction) injection system without pneumatic assistance

Abstract

The invention discloses an SCR (selective catalytic reduction) injection system without pneumatic assistance. The SCR injection system aims to overcome shortcomings of complicated structure, high manufacturing cost and poor atomizing effect for urea solution injected to an exhaust pipe of an existing SCR injection system. The SCR injection system comprises a urea adding device, an injection device, a control device, an SCR reaction device and a cooling device; the control device is electrically connected with the urea adding device and the injection device, the injection device is connected with the SCR reaction device, both the cooling device and the urea adding device are connected with the injection device, the injection device comprises a nozzle, the nozzle comprises a connecting seat and a needle valve assembly, the upper end of the connecting seat is connected with a support seat, a return spring is arranged in the support seat, and an electromagnet is sleeved on the outside of the support seat; and the needle valve assembly comprises a needle valve body and a needle valve, an electromagnetic armature is arranged above the needle valve body, a needle valve seat is fixedly connected to the lower end of the needle valve body, an injection hole is arranged on the needle valve seat, the lower end of the needle valve is matched with the injection hole and is hermetically connected with the injection hole, an atomization cyclone sheet is arranged on the needle valve seat, and a guide plate is arranged on the atomization cyclone sheet.

Description

[0001] technical field [0002] The invention relates to an exhaust purification system of an internal combustion engine, more specifically, it relates to a non-aerodynamic auxiliary SCR injection system with high conversion rate. [0003] Background technique [0004] SCR technology is installed in the exhaust system of diesel vehicles to catalytically reduce NOx in diesel engine emissions to N 2 and 0 2 The catalytic reduction device uses urea aqueous solution as the reducing agent. The urea aqueous solution is sprayed into the exhaust pipe to decompose into carbon dioxide and ammonia water. The ammonia water is used as the reducing agent to reduce NOx into pollution-free nitrogen and water. Due to the relatively late start of the domestic automobile industry itself, the development of automobile environmental protection technology is relatively backward, especially the diesel engine SCR (Selective Catalytic Reduction) technology is still in its infancy. At presen...

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Problems solved by technology

[0007] The invention overcomes the disadvantages of complex structure and high cost of the SCR injection system, and the poor atomization effect of the urea solution injected into the exhaust pipe, and provides a non-pneumatic auxiliary SCR injection system, which has a simple structure, low manufacturing cost, and can be injected into the exhaust pipe. The urea solution atomization effect of the exhaust pipe is good, and the conversion rate of NOx is high

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