FI106397B - Fuel injection pump for internal combustion engines with piston - Google Patents

Description

106397

Fuel Injection Pump for Impact Piston Engines - The invention relates to a fuel injection pump for percussion piston engines according to claim 1.

An injection pump of this type is known from EP-A-0 267 894. In this injection pump, to displace the injection time, the cylinder is moved against the spring force by fuel. The cylinder end faces are pressurized by the pressure medium depending on the operating variables, such as speed, charge pressure, temperature and / or load, with the pressure medium pressure being controlled.

It is an object of the invention to provide an injection pump which is implemented simply and is optionally connected to two fixed injection times.

This object is achieved by an injection pump according to the invention, which is characterized in what is stated in the characterizing part of claim 1.

The end positions give an earlier injection time, which in continuous operation ensures lower fuel consumption and a slightly higher NOx concentration, and a later injection time, which guarantees 20 pollution-free operation and a lower NOx concentration.

The cylinders moving between the two end positions and the hydraulic control circuit allow direct and simple connection of the injection pump from one injection point to another one.

,,; | ' Some structural examples of the invention will now be explained in more detail by means of silicon cartilage. In this case • 1 · 1: 1 · 1; Figure 1 is an axial sectional view of the fuel injection pump with the cylinder · · · in its second end position,] ···. Fig. 1a is an axial section through one section of the injection pump with the cylinder in its second end position, Fig. 2 is an axial sectional view corresponding to Fig. 1 of the modified injection pump, Fig. 3 is an axial sectional view of the injector pump according to Fig. , and. ···. Figure 4 is an axial sectional view similar to Figure 2 of yet another embodiment of a syringe pump.

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According to Fig. 1, the fuel injection pump has a housing 1, which at its upper end shown in Fig. 1 is sealed by a lid 2. A housing 3 is provided with a cylinder 3 in which an axially movable piston 4 is oriented from below. The lower end of the piston 4 shown in Fig. 1 is in communication with the camshaft actuator 5 in a known manner, not shown in more detail. The upper end portion of the piston 4 shown in Fig. 1 forms a first guide edge 5 which acts on the transverse bore 6 through the cylinder 3 and determines the start of the pump feeding operation. As shown in Fig. 1, the piston 4 has a second guide edge 7 inclined below the first guide edge 5, which is inclined with respect to the axis of the piston 10, which also acts with the hole 6 and determines the end of the injection pump supply operation. As shown in Fig. 1, above the end surface of the piston 4 forming the guide edge 5 is a pump supply space 8 defined by a cylinder 3 and a central extension 9 of the lid 2 facing the cylinder bore. From the supply space 8 through the cover 2 there is a central duct 15 10 connected at its upper end to a pressure line (not shown) connected to the injection nozzle of a diesel-engine percussion piston engine and through which fuel is intermittently injected into the working cylinder of the machine. The percussion piston engine engine is installed as a propulsion engine for a marine vessel.

At the feed space 8, outside the cylinder 3, there is a surrounding ren-20 gutter 11 to which the transverse hole 6 of the cylinder 3 is connected. In addition, a channel 12 formed in the housing 1 extends into the annular space 11, along which fuel (arrow A) is fed in a known manner (not shown further). Excess fuel is led from the annular space 11 to the conduit 13 formed in the housing 1 and through the tube (not shown) to the manifold (arrow B).

ltl '{25 As shown in Fig. 1, the pump housing 1 is provided with an annular annular pressure chamber 15 disposed below it, which ··· · ♦ · is connected to the housing 1 via a channel 16 formed by hydraulic pressure. At the pressure chamber 15, the outer diameter D of the cylinder 3 is reduced to a diameter d, thereby forming a shoulder 18 which rests on the flat annular surface 19 of the pressure chamber 15 as shown in FIG. greater than diameter d but smaller than • · ·; · * outer cylinder D. The feed line 17 is branched by a line 20 having a dual: T: bypass valve 21 and connected to a passage 22 in the housing 1 at the upper end of the cylinder 3 and associated with a pressure space 25. As depicted in Figure 1, the pressure space 25 is inserted between the upper end surface of the cylinder 3 and the lid 2. The pressure space 25 is formed by a ring

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a valve having an outer diameter corresponding to the outer diameter D of the cylinder 3 and an inner diameter corresponding to the outer diameter d 'of the extension 9 to the cylinder 9 of the lid 2.

The injection pump described above operates as follows: With the double action valve 21 in the position shown in Figure 1, the hydraulic pressure medium 5 is supplied to both the pressure chamber 15 and the pressure 25. Because the pressure acting shoulder 18 is smaller than the end surface (D - d ') In the upper pressure chamber 25, the cylinder is pressed against the annular surface 19, since the upper pressure chamber 25 has a higher compression force. As the piston 4 moves upward, the pressure of the fuel in the feed space 8 increases from the moment the first guide edge 5 passes the upper limit of the transverse hole 6. Simultaneously, the fuel passes through the central passage 10 to the above-mentioned spray nozzle through which the fuel is injected into the working cylinder when the injection pressure has been exerted. The spraying is interrupted when the second guide edge 7 passes the lower limit of the transverse hole 6. At present, the pressure in the fuel in the feed space 8 drops to 15, and the fuel may be discharged through the transverse bore 6, the annular space 11, and the channel 13. The above described spraying takes place when the ship is moving on the high seas, whereby the efficiency of the propulsion engine is high and the NOx concentration is relatively high. As the ship approaches the coast, where the propulsion system's environmental protection regulations are critical, that is, the NOx concentration must be as low as possible 20, the double-acting valve 21 is moved, for example, manually, by compressed air or electrical signal. In this position, the pressure in the upper pressure chamber 24 drops and the hydraulic pressure is discharged from this space to the manifold. Further fed along line 17; The pressure agent j 'then acts only on the shoulder 18 in the lower pressure chamber 15.

i: ': 25 As a result, the cylinder 3 moves up until its upper end contacts: ***: the lid 2. The transverse channel 6 is therefore also moved upward, and as the piston 4 moves, the fuel supply and injection also start later. . *: *. than before because it takes longer to move the first guide edge 5 across the upper limit of the transverse hole • · «6. Exhaust emissions leaving the propulsion engine ... 30 therefore have a lower NOx concentration. Cylinder 3 is in this position until the vessel moves offshore again. When the double-acting vent 21 is then moved back to its position shown in Fig. 1, the cylinder 3 moves: T again to its lower end position, whereby the earlier start of spraying: **; based usage will restart.

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35 In the design example of Figure 2, the lower pressure chamber is »· * | placed in the annular space 11 so that the fuel pressure in the annular space affects the 106397 shoulder 18. A conduit 31 having a two-way valve 32 is connected to the conduit 22 of the housing 1 at higher pressures 25 by means of this dual-action valve 32 and the pressure chamber 25 may also be connected to the hydraulic pressure supply line 33.

As can be seen in Figure 2, with the double action valve 32 in the position shown, the pressure medium connection is maintained so that the pressure in the pressure chamber 25 holds the cylinder 3 against the fuel pressure on the shoulder 18 in the lower end position. The injection pump operates in the manner described with reference to Figure 1, i.e., the injection starts earlier when the ship is then 10 offshore. As the ship moves to the coastal waters, the double-acting valve 32 is moved to the right as shown in Figure 2 so that the pressure in the conduit 31 and then the pressure chamber 25 is reduced. The fuel compression force exerted on the shoulder 18 now moves the cylinder 3 to its upper end position, which corresponds to the position shown in Figure 1a. The transverse hole 6 of the cylinder 3 is now higher than the position 15 shown in Fig. 2, i.e. the injection pump injection starts later and the NOx concentration decreases.

In the structural examples of Figures 1 and 2, the hydraulic pressure medium fed through the conduits 17 and 33 may be diesel fuel, which however is supplied independently of the fuel supplied to the injection pump through the conduit 12. In the structural example of Fig. 3, the hydraulic pressure medium is the fuel taken from the diesel fuel fed to the pump. To this end, housing 1 is provided with a conduit 36 provided in the region of annular space 11, which is connected to conduit 37. Conduit 37 is connected via conduit 38 to conduit 22 communicating with upper pressure chamber 25. Housing 1 has conduit 39 opposite conduit 22 also connected to the pressure chamber 25 and connected to a conduit 40 associated with a conduit 13 'connected to the fuel outlet duct 13. The lines 13 'and 40 have a corresponding throttle point 41 and 42, respectively.

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In the position shown in Fig. 3, the double-acting valve 38, by means of a conduit 12, a portion of the fuel fed to the injection pump 30 is directed to the upper pressure chamber 25. The fuel pressure acting in this pressure chamber compresses the cylinder 3 to a lower end position corresponding to the when traveling in the open sea. When the ship enters the coastal waters, the double-acting valve 38 (Fig. 3) is moved to the right, which lowers the pressure in the pressure chamber 25, thereby fueling the shoulder 18. ·. 35, the cylinder 3 moves the cylinder 3 to the upper end position as shown in Fig. 1a.

Y * By means of duct 39, conduit 40 and both chokes 41 and 42, it is possible to continuously supply fuel through the pressure chamber 25 when the cylinder 3 is in the position shown in Fig. 3.

The structural example of Fig. 4 corresponds in general to that of Fig. 2, but as shown in Fig. 2, the hydraulic force itching on the shoulder 18 to 5 is now replaced by a coil spring 30. The spring 30 is around the lower end of piston 4 and clamps . Thus, in this embodiment, there is no special annular surface under the shoulder 18 of the housing 1.

With the pump in operation and the dual-action valve 32 in the position 10 shown, the cylinder 3, by the hydraulic force of the pressure chamber 25, remains in its lower end position, which corresponds to the earlier start of the spraying. As the ship moves near the coast, the double-acting valve 32 (Figure 4) is moved to the right, thereby reducing the pressure in the pressure chamber 25. The compressive force of the coil spring 30 then compresses the cylinder to the upper end position so that spraying begins later.

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Claims (7)

A fuel injection pump for stroke engine combustion engines, said pump having a pump housing (1) containing a suction chamber (11), an inlet duct (12) and an outlet duct (13), a cylinder (3) forming a supply chamber ( 8), which cylinder is movably arranged in the pump housing between two end positions and at least one wall contains a radially directed shark (6) which is in communication with the inlet duct and the outlet duct, and a piston (4) arranged axially movable in the cylinder and includes a first guide edge (5) which determines the beginning of the pump supply, and a second guide edge (7) which determines the end of the pump supply, the two guide edges cooperating with the heel (6) and wherein the cylinder ( 3) in the pressurized state is poured into one end position and, by pressure reduction, can be displaced to the other end position, characterized in that in order to keep the cylinder (3) in the second position, pressure setting is also arranged on the front side of the cylinder (3), which is located on the side of the cylinder (3) facing the drive side of the piston (4), this front side being smaller than the front side facing away from the driving side of the piston in order for the cylinder (3) to shift to the driving side of the piston when the pressure setting the front pages are the same. 2. A pump according to claim 1, characterized in that the side of the cylinder (3) facing away from the drive side of the piston (4) is provided with a pressure chamber (25), and that the control circuit opens into the pressure chamber for. pressurizing the cylinder (3) with pressure medium. The pump according to claim 1, characterized by the • ♦ · «: side of the cylinder (3) facing the drive side of the piston (4) is a pressure chamber. (15) and that the control circuit opens into the pressure chamber (15) for pressurizing the cylinder (3) with pressure medium. 'III Pump according to any of claims 1-3, characterized in that the cylinder (3) with the front side (18) facing the drive side is arranged inside the suction chamber (11) of the housing (1). Pump according to claim 1, characterized in that the control circuit has a supply line (17) for pressure medium and that the supply line (17) opens into the pressure chamber (15) for continuous pressure setting of pressure. · ·. chamber with pressure medium. Pump according to any of claims 1-5, characterized in that the control circuit is connected to a pressure-increasing source, e.g. suction room or pump. «♦ i« * 9 106397 Pump according to any of claims 1-6, characterized in that a hydraulic control circuit with a directional valve (21, 32, 38) is arranged for controlling the cylinder (3) by supply or discharge of pressure medium. 5 t • 4 «« 1 · * * 1 1 * «· · * · · • I1 I ♦ # · * · • ♦ • · · ♦ * · 1 • ·« «• 1« • · V «·« IM • »• · • 1 · *** II • · · * * · 1 • · · Ml * 1 • ·> ♦ 1 · 1« I «1 • ·