CN115726865A - DPF fuel injection device and aftertreatment system - Google Patents

Abstract

A DPF fuel injection device comprises a pump body, a solenoid device and a plunger pump, wherein the solenoid device and the plunger pump are positioned in the pump body, the pump body comprises a liquid inlet and a liquid outlet, the plunger pump comprises a sleeve, a plunger, a liquid inlet valve and a liquid outlet valve, a pressure feeding volume cavity is formed between the liquid inlet valve and the liquid outlet valve, one of the sleeve and the plunger is a moving piece, the sleeve and the plunger form a sliding fit, and the moving piece moves in a limited stroke, so that pulse high pressure is formed in the pressure feeding volume cavity, and fuel is quantitatively fed. The regulating valve is communicated with the pressure feeding volume cavity, and the injection device has high control precision, stable flow and strong adaptability.

Description

DPF fuel injection device and aftertreatment system

Technical Field

The invention belongs to the field of engine emission control, and particularly relates to a fuel metering injection device, in particular to a combustion regeneration system of an engine exhaust filter (DPF).

Background

Diesel engines are the most important prime mover in the world today due to their high thermal efficiency and low carbon dioxide emissions, and are widely used in road and off-road vehicles, construction machinery, stationary power equipment, and the like. Direct injection supercharged gasoline engines are also becoming more popular in vehicular engines because of their higher thermal efficiency and specific power than conventional gasoline engines. However, combustion of diesel engines and gasoline direct injection engines is accompanied by generation of various pollutants including nitrogen oxides (NOx), particulate Matters (PM), hydrocarbons (HC), carbon monoxide (CO), and the like, which can seriously pollute the atmospheric environment and endanger biological health. With the increasing prominence of environmental problems, energy conservation and emission reduction have become the most important subjects of the engine industry, and a series of engine and vehicle emission standards are introduced in many countries of the world and are increasingly strict. In this regard, internal combustion engine powered vehicles require better combustion control and exhaust after-treatment systems are installed in an attempt to meet increasingly stringent emission requirements.

The exhaust aftertreatment includes disposing various catalytic converters and traps in an exhaust pipeline, taking a Diesel Particulate Filter (DPF = Diesel Particulate Filter) as an example, a DPF system filters soot by using a ceramic or metal carrier so as not to be discharged into the atmosphere, but as the soot Particulate accumulates in the Filter carrier, the exhaust back pressure of an engine continuously rises, and at this time, fuel oil needs to be atomized and injected into the exhaust system to increase the exhaust temperature, so that the accumulated soot is burned off, and regeneration of the Particulate Filter (DPF) is completed. During the process, the metering precision of fuel injection needs to be strictly controlled, for example, insufficient injection can cause incomplete regeneration, and excessive injection can cause overhigh temperature and burn the DPF filter carrier.

In the prior art, there are two main injection metering technology routes. One technical route is that the liquid supply pump system only provides a constant pressure, and the injection amount is metered according to the opening time of the electromagnetic nozzle, such as common rail systems of gasoline and diesel oil, and urea injection devices such as DENOXTRONIC 2.2 sold by Bosch in Germany; the other is a plunger pump metering device driven by a solenoid device, which meters the injection amount of each pulse depending on the displacement amount of a plunger. In the latter case, U.S. Pat. No. US20150082775A discloses a metering device, namely: a solenoid-driven plunger pump is provided, in which a plunger sleeve is fixed to a solenoid, and a plunger is fixed to an armature and reciprocates in a T-shaped space with a fixed stroke, and the injection amount of a single pulse is determined by the stroke of the plunger. The disadvantages of the metering device are: the plunger is connected with the armature head and the armature tail, the axial size is long, the moving mass is large, if a friction pair is provided by completely depending on the matching of the plunger and the sleeve, the gravity center of a moving part is arranged outside a supporting friction pair, and the durability is influenced by the moving inertia; if a sliding support of the plunger (i.e. the magnetic SLEEVE, MAGNET sliding 67) or an armature sliding support is arranged at the other end of the spring opposite to the SLEEVE, the coaxiality of the SLEEVE and the sliding support needs to be strictly controlled, the manufacturing difficulty is high, and particularly, an additional spring seat (snap ring 68) needs to be arranged between the sliding support of the plunger and the spring, and the installation process of the spring seat is also complicated. In addition, the frequency of plunger reciprocation is limited due to the relatively large mass of moving parts and friction.

In addition, the degree of atomization of the fuel also directly determines the effectiveness of the exhaust treatment. The existing injection metering system adopts a device which takes an external diaphragm or a plunger pump driven by a detention motor as a power source to generate injection pressure, and directly injects DEF liquid into an engine exhaust pipe, however, the atomization effect generated by actual injection is not ideal.

In view of the demands for the exhaust gas post-treatment device, such as the metering accuracy and the injection effect, it is necessary to provide a new solution with good atomization effect and high metering accuracy without increasing the cost.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection device having high control accuracy, stable flow rate, and high adaptability.

In order to achieve the purpose, the invention adopts the technical scheme that the DPF fuel injection device comprises a pump body, and a solenoid device and a plunger pump which are positioned in the pump body.

The pump body comprises a liquid inlet and a liquid outlet, the solenoid device comprises a solenoid coil and an armature, the plunger pump comprises a sleeve, a plunger, a liquid inlet valve and a liquid outlet valve, and a pressure conveying volume cavity is formed between the liquid inlet valve and the liquid outlet valve.

One of the sleeve and the plunger is a moving part, and both are cylindrical bodies, and the inner wall of one of the sleeve and the plunger forms a sliding matching part which is closely matched with the outer surface of the other plunger and can move freely. The moving part moves in a limited stroke, so that pulse high pressure is formed in the pressure feeding volume cavity to supply fuel quantitatively.

The DPF fuel injection device comprises a front limit and a rear limit, so that one of the sleeve and the plunger can reciprocate in a specific stroke between the front limit and the rear limit, and the liquid output quantity of the relative movement stroke of the sleeve and the plunger is limited by a geometric structure, so that the single injection quantity of the DPF fuel injection device is certain, and the liquid output quantity in unit time can be changed in a mode of changing the reciprocating movement frequency.

One of the sleeve or the plunger comprises a side hole in the side wall, and the liquid inlet valve comprises a wall surface provided with the side hole and the other of the plunger or the sleeve.

Further, the DPF fuel injection device includes a regulating valve communicating with the pressure-feed volume chamber. The regulating valve is a ball valve, and the opening pressure of the regulating valve is smaller than that of the liquid outlet valve, so that smooth liquid inlet is ensured.

The working process of the DPF fuel injection device comprises that fuel enters from the liquid inlet and reaches the pressure feeding volume cavity, the armature drives the moving part to move to and fro under the driving of the solenoid device, the volume of the pressure-feeding volume cavity is changed alternately, when the liquid pressure in the volume cavity is increased, the liquid outlet valve is opened, the liquid is output from the liquid outlet, and as the volume cavity is enlarged, the liquid inlet valve is opened, and the liquid is replenished into the cavity. In the process, the regulating valve is opened before the liquid inlet valve, so that the armature return process is ensured to be smooth. The armature and the moving part of one of the sleeve or the plunger are designed in one piece.

The DPF fuel injection device is applied to a DPF aftertreatment system, and includes a low-pressure oil pump and an oil valve, the low-pressure oil pump supplies low-pressure fuel oil and delivers the low-pressure fuel oil to the DPF fuel injection device, the low-pressure oil pump and the DPF fuel injection device are connected through a pressure oil pipe, and the oil valve is arranged on a pipeline between the low-pressure oil pump and the DPF fuel injection device.

Further, the DPF after-treatment system also comprises an air source, an air valve and a mixing cavity, wherein the air source is connected with the mixing cavity through an air pipe, and the air valve is arranged on a pipeline between the air valve and the mixing cavity and used for controlling the on-off of compressed air.

The liquid outlet of the DPF fuel injection device is communicated with the mixing cavity, and high-pressure fuel and compressed air form gas-liquid mixed fluid in the mixing cavity. The mixing cavity comprises a mounting seat and a sealing device, and the DPF injection device is connected with the mixing cavity through the mounting seat and is sealed by the sealing device. The liquid outlet and the mixing cavity can be connected through a pipeline.

The DPF fuel injection device also comprises an injector, and gas-liquid mixed fluid in the mixing cavity is atomized and output through the injector. The injector may be a swirler. The mixing chamber is designed as one piece with the injector to reduce piping.

The invention is further defined or optimized by the following technical scheme in combination with the attached drawings and the embodiment.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a DPF fuel injection device provided by the present invention.

FIG. 2 is a schematic diagram of an exemplary DPF system utilizing a DPF fuel injection apparatus provided by the present invention.

Detailed Description

The present invention provides a schematic structural diagram of an embodiment of a DPF fuel injection device, as shown in fig. 1, including a pump body 1, and a solenoid device 2, a plunger 107, a pump 3, a front limit 100, a rear limit 113, and a return spring 111 located in the pump body 1.

The solenoid device 2 has a structure satisfying a basic principle of generating an electromagnetic driving force, and includes a solenoid coil 102, an armature 109 driven by an electromagnetic force, a yoke 115 and a magnetism isolating ring 103, the yoke 115 is disposed around the coil 102, the yoke located inside the coil 102 is an inner yoke 101, the inner yoke 101 is partitioned into an upper inner yoke 101a and a lower inner yoke 101b by the magnetism isolating ring 103, the upper inner yoke 101a, the lower inner yoke 101b and the magnetism isolating ring 103 form a substantially cylindrical space for the armature 109 to reciprocate, i.e., an armature chamber, an outer contour of the armature 109 is substantially cylindrical, a front end surface of the armature 109 is located near the magnetism isolating ring 103, when the coil 102 is energized, the armature 109 moves in a direction of the lower inner yoke 101b under an electromagnetic force, and when the coil 102 is de-energized, the armature 109 returns in a direction of the inner yoke 101a under a spring force of a return spring 111, thereby forming a reciprocating motion of the armature 109. The yoke 115 and the armature 109 are made of a magnetic conductive material, and the magnetism isolating ring 103 is made of a low magnetic conductive material.

The plunger 107 pump 3 comprises a sleeve 108, a plunger 107, an inlet valve 116 and an outlet valve 106, the inlet valve 116 and the outlet valve 106 defining a pumping volume 114 therebetween. In the present embodiment, the sleeve 108 is used as a moving element, the plunger 107 includes a plunger inner hole, and the sleeve outer surface 108a and the plunger inner hole surface 107a constitute a close-fitting and freely movable sliding coupling element.

The sleeve 108 is located inside the armature 109 and is integrated with the armature 109. Wherein all geometric elements that fulfill the function of the sleeve 108 are formed by machining of the armature 109. The sleeve 108 and the plunger 107 are both cylindrical, the plunger 107 including a central bore extending axially therethrough, the sleeve 108 being reciprocable within the central bore.

The outlet valve 106 is a ball valve that opens by spring force, and the inlet valve 116 includes a through hole formed in the inner surface 107a of the plunger, which forms a slide valve with the outer surface 108a of the sleeve.

The pump body 1 comprises an inlet port 112 and an outlet port 105. The front limit 100 and the rear limit 113 are arranged on the motion stroke of the moving part and are fixed relative to the pump body 1. The front limit 100 is close to the liquid inlet 112, and the rear limit 113 is close to the liquid outlet 105. The armature 109 (sleeve 108) reciprocates between the front limit 100 and the rear limit 113 with a specific stroke, so that a pulsed high pressure is formed in the pumping volume 114 to meter the fuel. The liquid output per unit time will vary in such a way that the frequency of the reciprocating movement is varied.

Further, the DPF fuel injection device includes a regulating valve 110, and the regulating valve 110 is connected to a pressure-feed volume chamber 114. The regulating valve 110 is a ball valve, and the opening pressure of the regulating valve is smaller than that of the liquid outlet valve 106, so that the smooth liquid inlet is ensured.

The DPF fuel injection apparatus of the present embodiment operates as follows.

In the initial state, the armature 109 is urged against the front limit 100 by the spring force of the return spring 111, and pressurized fuel enters through the inlet port 112 to fill the pumping volume chamber 114, while the inlet valve 116 and the regulating valve 110 are both in the open state. When the armature 109 is acted by the electromagnetic force of the solenoid and starts to move towards the rear limit 113, the pressure in the pressure feeding space starts to increase, the regulating valve 110 is closed, the armature 109 continues to move downwards, then the outer wall of the sleeve 108 covers the oil inlet side hole of the plunger 107, the liquid inlet valve 116 is closed, the pressure in the pressure feeding volume chamber 114 continuously increases, when the liquid pressure is larger than the spring force of the liquid outlet valve 106, the liquid outlet valve 106 is opened, and the working liquid is output from the liquid outlet 105. When the armature 109 is blocked by the rear stop 113, the pumping stroke is terminated.

When the solenoid device 2 is de-energized, the armature 109 starts the return stroke by the spring force of the return spring 111, the pressure inside the pressure-feeding volume chamber 114 starts to decrease, the regulating valve 110 is opened by the vacuum force, the pressure inside the pressure-feeding volume chamber 114 further decreases, the armature 109 continues to retract, the liquid inlet valve 116 opens, the low-pressure fuel quickly fills the pressure-feeding volume chamber 114 by the differential pressure, and the liquid outlet valve 106 is closed by the valve spring force. When the continued movement of the armature 109 is stopped by the front stop 100, the DPF fuel injection assembly returns to the initial state and waits for the next cycle.

Fig. 2 is a schematic structural diagram of an embodiment of the DPF aftertreatment system according to the present invention, which includes a low-pressure oil pump 200, an oil valve 201, an air source 206, an air valve 205, a mixing chamber 202, and an injector 203.

The low-pressure oil pump 200 supplies low-pressure fuel oil and conveys the low-pressure fuel oil to the DPF fuel injection device, the low-pressure oil pump 200 is connected with the DPF fuel injection device through a pressure oil pipe 207, and the oil valve 201 is arranged on a pipeline between the low-pressure oil pump and the DPF fuel injection device and is used for controlling the on-off of an oil supply oil path.

The air source 206 is connected with the mixing cavity 202 through an air pipe 208, and the air valve 205 is arranged on a pipeline between the air source and the mixing cavity and used for controlling the on-off of the compressed air.

The liquid outlet 105 of the DPF fuel injection device is communicated with the mixing chamber 202, and the high-pressure fuel and the compressed air form gas-liquid mixed fluid in the mixing chamber 202. The gas-liquid mixed fluid in the mixing chamber 202 is atomized and output by the injector 203 and sprayed into the exhaust pipe 208. The injector 203 may be a swirl nozzle, and the mixing chamber 202 may be designed integrally with the nozzle to reduce the amount of piping at the rear end of the mixing chamber 202 and prevent fluid loss or fluid pressure fluctuations in the piping from affecting the metering accuracy.

Further, the mixing chamber 202 and the DPF injecting device may be connected by a pipe, or the DPF injecting device may be fixed to the mixing chamber. In the fixed mode, the DPF injector is connected to the mixing chamber 202 through the mounting seat and is sealed by the sealing device.

The above examples are only for illustrating the essence of the present invention, but not for limiting the present invention. Any modifications, simplifications, or other alternatives made without departing from the principles of the invention are intended to be included within the scope of the invention.

The present invention is not concerned with parts which are the same as or can be implemented using prior art techniques.

Claims (10)

1. A DPF fuel injection device comprises a pump body, a solenoid device and a plunger pump, wherein the solenoid device and the plunger pump are positioned in the pump body, the pump body comprises a liquid inlet and a liquid outlet, the plunger pump comprises a sleeve, a plunger, a liquid inlet valve and a liquid outlet valve, and a pressure feeding volume cavity is formed between the liquid inlet valve and the liquid outlet valve.

2. The DPF fuel injection apparatus of claim 1, including a forward limit and a rearward limit to effect one of the sleeve or the plunger to reciprocate between the forward limit and the rearward limit with a specified stroke such that a single injection amount of the DPF fuel injection apparatus is fixed.

3. The DPF fuel injection apparatus of claim 2, wherein one of the sleeve or the plunger includes a side hole in a side wall, and the intake valve is comprised of a wall provided with the side hole and the other of the plunger or the sleeve.

4. The DPF fuel injection apparatus of claim 3, comprising a regulator valve, the regulator valve communicating with the pressure-feed volume chamber.

5. The DPF fuel injection apparatus of claim 4, wherein the regulating valve is a ball valve having an opening pressure smaller than that of the outlet valve to ensure smooth inlet.

6. A DPF aftertreatment system using the DPF fuel injection apparatus according to any one of claims 1 to 5, comprising a low-pressure oil pump supplying low-pressure fuel to the DPF fuel injection apparatus, an oil valve connected between the low-pressure oil pump and the DPF fuel injection apparatus via a pressure oil pipe, the oil valve being disposed on a pipe therebetween.

7. The DPF aftertreatment system of claim 6, comprising a gas source, a gas valve and a mixing chamber, wherein the gas source and the mixing chamber are connected through a gas pipe, and the gas valve is arranged on a pipe between the gas valve and the mixing chamber and used for controlling the on-off of compressed air.

8. The DPF aftertreatment system of claim 7, wherein the fluid outlet of the DPF fuel injection device is in communication with a mixing chamber, and the high pressure fuel and the compressed air form a gas-liquid mixture fluid in the mixing chamber.

9. The DPF aftertreatment system of any one of claims 6-8, comprising an injector, wherein the gas-liquid mixture fluid in the mixing chamber is atomized and output through the injector.

10. The DPF aftertreatment system of claim 9, wherein the mixing chamber is integrally designed with the injector.

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