DE4404944C2 - Fuel control system with a boost pressure compensator for a fuel injection pump - Google Patents

Description

The invention relates to a fuel control system with a boost pressure same for a fuel injection pump with the features of the Oberbe handle of claim 1.

From the prior art it is known that a diesel engine equipped with a turbocharger is equipped with a boost pressure equalizer having a fuel injection pump for the fuel supply to the engine, so that the amount of fuel to be injected increases as a function of an increase in the air volume generated by a turbocharger the motor rotates at high speed (JP-U-1-139038). It is thus possible, as shown in FIG. 7, for example, to change the behavior with respect to the amount of fuel to be injected by the fuel injection pump having the same pressure according to dd′-e′-ef when the engine speed exceeds the value N2, while the behavior regarding the amount of fuel to be injected by a fuel injection pump is abcdef without a boost pressure compensator.

The fuel injection pump with a charge pressure equalizer that comes from the Known in the art, however, has the problem that one partly with the intention of behavior regarding the force to be injected amount of substance d-d′-e′-e to achieve during operation at high speeds Chen, the amount of fuel to be injected during the engine start-up period be greater than or equal to the amount of fuel to be injected Q3 must, as shown with the interval a'-b '. These to be injected However, fuel quantity Q3 far exceeds the correct amount to inject de Q2 fuel quantity. On the other hand, the attempt to inject Fuel quantity to the correct value Q2 during the engine start-up period limit, result in the increase in force to be injected amount of substance during operation at high speeds to this value Q2 is limited. Therefore, it is not possible to use the appropriate amount of fuel injected depending on that of the turbocharger witnessed increase in intake air volume.  

The object of the invention is therefore a fuel control system with a boost pressure compensator for a fuel injection pump to design and develop that it is possible to inject the force to increase the amount of substance sufficiently during operation at high speeds and a suitable one to be injected at the same time during the engine start-up period Maintain fuel quantity.

According to the invention, the object outlined above is through a fuel control system with a charge pressure compensator for a fuel injection pump solved with the features of the characterizing part of claim 1. At With such a structure, the starter lever rotates during engine startup period in accordance with the tension lever so that when the Boost pressure compensation lever in the direction of increasing the injected Fuel amount rotates, the size of the rotation is also increased the tension lever in the direction of increasing the force to be injected amount of substance runs in order depending on an increase in the boost pressure to achieve a suitable amount of fuel to be injected.

In the prior art, the engine starts during the initial stage period the danger that the amount of fuel to be injected is the correct one Amount of fuel to be injected by far during the engine startup period exceeds because during this stage the starting lever is independent from the tension lever in the direction of increasing the force to be injected amount of fabric rotates. According to the invention, it is now precisely during this beginning stage of the engine start-up period by the amount of fuel to be injected a limiting element arranged on the starter lever can be limited in that this limiting element in contact with the charge pressure compensation lever comes, so that the above problem is solved.

For a further understanding of the details of the present invention further on the explanation of a preferred embodiment using the Drawing referenced. In the drawing shows  

Fig. 1 in cross-sectional fuel injection pump, the essential parts of a motor according to the invention,

The charging pressure compensation lever and the governor mechanism as they are set in the fuel injection pump of FIG. 1 during the initial stage of engine start-up period Fig. 2 in detail, wherein the collecting lever is illustrated in cross-section,

Fig. 3 in detail the boost pressure compensating lever and the governor mechanism as they are set in the fuel injection pump of FIG. 1 during the initial stage of engine start-up period, wherein the collecting lever and the tension lever are shown in cross-section,

Fig. 4 in a detailed view of the side of the centrifugal governor tube boost pressure compensating lever and the Fliehkraftregelmecha mechanism as they are spent ver in the fuel injection pump of FIG. 1,

Fig. 5 is a perspective exploded view of the various elements of the governor mechanism,

Fig. 6 in detail the boost pressure compensation lever and the centrifugal control mechanism, as set in the fuel injection pump of Fig. 1 during the engine start-up period, the collecting lever being shown in cross section and

Fig. 7 in the diagram of the behavior of the fuel injection pump according to the invention with respect to the amount of fuel to be injected as a function of the engine speed.

The following is a description of an embodiment of the invention given with reference to the drawing.  

Fig. 1 shows a fuel injection pump 1, which uses a charging pressure equalizer to mechanically compensate for the operation performed by the governor mechanism controlling the amount of fuel.

The fuel injection pump 1 supplies a chamber 2 with fuel from a fuel tank with the aid of a supply pump (not shown). A piston 3 is arranged in a piston body 5 which is fixed to a pump housing 4 . This allows the piston 3 to move freely back and forth. The base of the piston 3 touches a cam 6 , is connected to the cam 6 and is pressed down by a piston spring 7 . The cam 6 is connected by means of a coupling to the drive shaft in such a way that the cam 6 moves in the same direction as the shaft. Due to the rotation of the cam disc 6 , a reciprocating motion is transmitted to the piston 3 , so that both the intake and compression of the fuel and the distribution of the fuel are carried out by rotation.

During the charging stroke, so when the piston 3 moves to the left in FIG. 1, the fuel in the chamber 2 is admitted through an inlet opening 8 via one of the charging grooves 9 into a pump chamber 10 , which is separated from the piston body 5 and the Piston 3 is surrounded. The charging grooves 9 are designed at the tip of the piston 3 in the direction of the shaft. During the compression stroke, so when the piston 3 moves to the right in Fig. 1, the inlet opening 8 and the Aufladungsnu 9 are separated from each other. At the same time, the fuel compressed in the pump chamber 10 is passed via a longitudinal channel 11 in the piston 3 through a distribution opening to a pressure valve 12 , so that the fuel can be injected from the injection nozzle into the cylinder of the engine.

A control tube 13 is placed from the outside on a part of the piston 3 which projects beyond the piston body 5 in such a way that the control tube 13 can move back and forth freely. As soon as a shut-off opening 14 , which communicates with the longitudinal chamber 11 in the piston 3 , crosses the end of the control tube 13 and thus communicates with the chamber 2 , the compressed fuel flows into the chamber 2 and the fuel delivery to the injection nozzle is stopped so that the injection ends. In other words, because this process ends the fuel injection, the amount of fuel to be injected can be adjusted by adjusting the position of the control tube 13 . Thus, when the Steue extension tube 13 in Fig. 1 to the right is moved (direction A), it increases the fuel injection quantity, and when the control tube 13 moves to the left (direction B), the injected power is lowered molar.

A boost pressure compensator 15 is arranged on an installation housing 16 , which represents the upper part of the pump housing 4 , and is provided with a membrane 17 within the installation housing 16 . The membrane 17 is clamped between the housing elements which form the installation housing 16 . The membrane 17 divides the interior of the built-in housing 16 into two areas, one area forming a chamber with atmospheric pressure 18 , which is connected to the environment and therefore has atmospheric pressure. The other area represents a boost chamber 19 into which intake air is introduced at a pressure (supercharging pressure) with which the engine is supplied by a turbocharger. A rod 20 is net on the side of the chamber with atmospheric pressure 18 and attached to the membrane 17 . The force of a spring 21 acts in Rich direction of the boost chamber 19 , the spring 21 is arranged in the chamber with atmospheric pressure 18 . Therefore, the rod 20 is kept in a position where the supercharging pressure, the atmospheric pressure and the force of the spring 21 are in balance. Now, when the supercharging pressure increases with the increase in the engine speed, the rod 20 moves downward in FIG. 1 (direction C).

A conical part 22 is formed near the lower end of the rod 20 and the diameter of the conical part 22 decreases steadily in the direction of the upper end of the rod 20 . A pin 23 is arranged such that one end thereof is in contact with the conical part 22 and that it can be moved back and forth in the direction of the diameter of the rod 20 . The other end of the pin 23 is in contact with the upper end of a charge pressure compensation lever 24 , which is rotatably supported by means of a shaft arranged on the pump housing 4 .

The governor mechanism is connected to the already described previously Steue extension tube 13 is connected and res able to change the position of the Steuerungsroh. 13 As shown in FIGS. 2 and 5, 25 is the governor mechanism mainly consists of a collector lever 26, an embedded in the collective lever 26 tension lever 27, an embedded in the clamping voltage lever 27 cause lever 28 and an embedded in the starter lever 28 Angleichhebel 29th

Two opposing surfaces 30 a and 30 b of the lower end part 30 of the collecting lever 26 have the shape of a horizontal U and are arranged on a pivot pin (axis center point M1). This pivot pin extends at right angles to the surfaces extending in the direction of the piston 3 , so that the collecting lever 26 can rotate freely relative to the pump housing 4 . By a support spring 31, a force is applied in the left direction on the collecting lever 26 at a point below M1, the support spring 31 is disposed between the pump casing 4 and the lower end 30 of the collecting lever 26th Due to the force of this support spring 31 , the part 32 arranged at the upper end of the collecting lever 26 is pressed firmly against an adjusting screw 33 , which is arranged in the installation housing 16 . So the range of rotation of the collecting lever 26 with M1 as the fulcrum can be adjusted by adjusting the part of the adjusting screw 33 protruding from the pump housing 4 .

The tension lever 27 is supported by a first axis 36 (axis center M2) formed by the two opposite surfaces of the lower end part of the tension lever 27 is inserted, so that the voltage 27 is free to rotate lever. The location of the first axis 36 , that is, the location in which the tension lever 27 is supported, is lower than the axis center M1 of the collecting lever 26 . A governor spring 35 which, in turn, is fixed to the pump housing 4 between the clamping voltage lever 27 and a control lever 34 is disposed, exerts a force on the lower portion of the lever tension 27th If the control lever 34 is now rotated in the direction of an increase in the amount of fuel to be injected, the force exerted by the centrifugal force control spring 35 increases. As a result, the tension lever 27 is rotated by M2 toward the side on which the control lever 34 is located (direction D, see FIG. 2). A side surface of the tension lever 27 is provided with a bent-out part 38 which is designed in such a way that it projects beyond a second axis 37 (axis center point M3) and does not touch it. The second axis 37 is explained further below.

The starter lever 28 is carried by the previously mentioned first axis 36 ge, so that the starter lever 28 can rotate freely. The cause lever 28 is provided at the lower end with a ball head pin 39 is inserted into a tube 13 configured in the control pin base 13 a. The crank lever 28 is open on the side opposite the tension lever 27 and the upper protruding part 40 is bent and protrudes beyond the tenflächen Be. The upper protruding part 40 is in turn provided with a spring guide element 42 for a starter idler spring 41 which is arranged between the starter lever 28 and the tension lever 27 . At the same time, one end of a starter spring 43 (leaf spring) is attached to the upper protruding part 40 . The other end of the starter spring 43 contacts the tension lever 27 and exerts a constant force in the direction so that the tension lever 27 is separated from the starter lever 28 .

The leveling lever 29 is supported by the second axis 37 which is inserted through two opposing surfaces and through the upper part of the starter lever 28 so that the leveling lever 29 can rotate freely. The lower end of the adjustment lever 29 is provided with a fastening area 44 in the form of an extension bent into a U. A matching spring 45 exerts a force on a first protruding part 46 in the direction of the tension lever 27 and the first protruding part 46 is arranged in such a way that movement over a specific distance (L2) in the axial direction is possible. Wei ter is a second protruding part 47 on the back below M3 attached to the adjustment lever 29 so that it points in the direction of the voltage lever 27 .

A centrifugal governor shaft 50 , which runs in the same direction as the piston 3 , is arranged in a wall region of the pump housing 4 . The centrifugal governor shaft 50 is fitted in a gear 51 which rotates with the rotation of the centrifugal governor shaft 50 and is provided with a centrifugal weighting 52 which rotates in accordance with the gear 51 . At the tip of the centrifugal governor shaft 50 , a centrifugal governor tube 53 is provided in such a way that it can move back and forth in the direction of the axis of the centrifugal governor shaft 50 . A flyweight 54 is arranged in the weight holder 52 which opens outward under a centrifugal force. The centrifugal governor tube 53 is displaced when the centrifugal weight 54 opens, and the tip of the centrifugal governor tube 53 comes into contact with the leveling lever 29 between the first projecting part 46 and the second projecting part 47 , so that the leveling lever 29 in the direction of the tension lever 27th (Direction E) a force is exerted.

The middle part of the charge pressure compensation lever 24 is arranged on an axis (axis center point M4) in such a way that the charge pressure compensation lever 24 can rotate freely. The boost pressure compensation lever 24 is equipped with a contact surface 55 configured at the lower end, which limits the movement of the tension lever 27 and the starter lever 28 of the centrifugal control mechanism 25 already mentioned. In other words, the boost pressure balance lever 24 has a shape such that the part below M4 angeord designated part extends beyond the extended part 38 of the tension lever 27 , and the contact surface 55 is designed such that the end part in the longitudinal direction of the second axis 37th is bent. Be with this contact surface 55 both a sleeve 56 , which is placed from the outside on one end of the second axis 37 , as well as the bent-out part 38 of the tension lever 27 in contact. The sleeve 56 moves in accordance with the starter lever 28 and is the limiting element according to the present invention.

Since one end of the pin 23 faces the conical part 22 , the pin 23 can move in the direction I in Fig. 1 when the rod 20 moves down, so that the wastegate lever 24 can be rotated clockwise (direction F) . As a result, the contact surface 55 can move in such a direction that the area over which the tension lever 27 and the starter lever 28 can move increases.

Next, the operation of the fuel injection pump with the structure described above.

At the time of motor start-up period of the tension lever is pulled by the governor spring 35 27 as the first and the bent-out portion 38 of the tension lever 27 is provided with the contact surface 55 of lever 24 into contact Ladedruckaus equal. Under the influence of the force of the starter spring 43 , the starter lever 38 is in a state in which it is rotated in the direction E around the fulcrum M2 in such a way that the starter lever 28 is separated from the tension lever 27 . The governor tube 53 is retracted in one direction (H direction) and the bushing 24 is in contact so that the range of rotation about which the starter lever 28 can rotate is limited. Therefore, 13 in the direction of an increase in the amount of fuel (direction A) while the engine start-up period, even when the control tube is moved ensures that the control tube 13 is not up to the movement of the control tube moves 13 limiting position be. The control tube 13 stops as soon as the bushing 56 comes into contact with the charge pressure compensation lever 24 . It follows that the amount of fuel to be injected is set to the value Q2 as specified by ab in the curve shown in FIG. 7.

Starting from this state, the engine speed increases gradually and when the engine speed comes in the range between N1 and N2, the centrifugal force on the centrifugal weight 54 generates a movement that pushes out the centrifugal governor tube 53 . The adjustment lever 29 rotates about M3 and the first projecting part 46 comes into contact with the tension lever 27 . The adjustment lever 29 and the starter lever 28 are now pushed to the right until the second protruding part 47 also comes into contact with the voltage lever 27 . From this point on, the adjustment lever 29 rotates in accordance with the tension lever 27 about the pivot point M2. On the tension lever 27 is now both the force exerted by the centrifugal governor tube 53 via the first and second projecting part 46 and 47 as well as the force exerted by the centrifugal governor spring 35 in the opposite direction. Therefore, the tension lever 27 stops in its movement Be at a place where the two forces are in balance. If the control lever 34 is now rotated into a position in which the control lever 34 reaches the state with maximum load and the force of the centrifugal force spring 35 increases, the tension lever 27 rotates in the direction D about the pivot point M2 and the tension lever 27 stops, when the extended part 38 of the tension lever 27 comes into contact with the contact surface 55 of the charge pressure compensation lever 24 (see FIG. 6). In this state, however, there is a gap L1 (synonymous with the starting stroke) between the contact surface 55 of the charge pressure compensation lever 24 and the bushing 56 , which corresponds to the distance over which the starting lever 28 operates in accordance with the tension lever 27 . Therefore, the control tube 13 is in a position deviating from the position in the direction B taken during the initial stage of the engine start-up period, and the amount of fuel to be injected at the maximum load decreases compared to the value that was present during the initial stage of the engine start-up period. The amount of fuel to be injected at this stage is identified by Q1, so that section cd in the curve in FIG. 7 results.

If the charging pressure increases from the state just described, the membrane 17 is pushed towards the side of the chamber with atmospheric pressure 18 and the rod 20 moves downward (direction Rich C), so that the pin 23 in the direction I and the boost pressure compensation lever 24 move in the F direction. By this movement, and in that from the governor spring 35 on the tension lever 27 a force in Rich tung D is applied, the boost pressure equalizer lever 24 rotates in Rich tung F. Since the starter lever 28 in accordance with the Spannungshe bel 27 rotates, causing these Rotation that the control tube 23 moves in Rich direction of an increase in the amount of fuel to be injected (interval dd ').

In this way, the amount of fuel to be injected is increased depending on the increase in the boost pressure until the rod 20 has moved to its position limiting the movement and until the boost pressure compensation lever 24 has rotated in the direction F as far as possible. When the charge pressure equalization channel 24 has rotated as far as possible, the tension lever 27 also stops its movement and the amount of fuel to be injected remains constant at a value Q3, even if the charge pressure continues to rise with an increase in the engine speed (interval d′-e ′) .

Although not shown in the curve shown in FIG. 7, when the engine speed is further increased, the leveling lever 29 rotates about the second protruding part 47 as a fulcrum such that the leveling lever 29 presses the leveling spring 45 . This reduces the amount by which the first protruding part 46 protrudes by the distance L2 (opposite adjustment stroke). This causes the starter lever 28 to be rotated counterclockwise (direction G), and although the range of rotation is very small, the control tube 13 continues to move to the right (direction A). The amount of fuel to be injected is increased to a value greater than Q3.

If the engine speed is further increased beyond the value N4, the centrifugal governor tube 53 is pushed further out to the right, the adjustment lever 28 is pressed so that the adjustment lever 28 depresses the tension lever 27 , and the tension lever 27 in turn becomes a movement forced against the force of the centrifugal force spring 35 in the direction J. As a result, the amount of fuel to be injected is gradually reduced (interval e'-ef).

As has been described so far, the restriction of the rotation of the tension lever 27 and the starter lever 28 by the arrangement of the drawn-out part 38 of the tension lever 27 and the sleeve 56 arranged on the starter lever 28 and by contacting the sleeve 56 with the charge pressure compensation lever 24th limited. During the engine start-up period, the rotation of the starter lever 28 is limited in the direction of an increase in the amount of fuel to be injected by the bushing 56 , so that the correct amount of fuel to be injected Q2 is ensured as a setting during the engine start-up period. As a result, an amount of fuel to be injected can be ensured during the engine start-up period, which amount depends on the increase in the supercharging pressure. With this structure, the amount of fuel to be injected during the engine start-up period can be selected by selecting a specific diameter of the sleeve 56 to achieve a specific rotation range of the starter lever 28 toward increasing the amount of fuel to be injected. This enables effective control even if tolerances due to manufacture or assembly occur in the various components.

It should also be mentioned that, although in this embodiment, the limiting element is the bushing 56 , which is placed on the second axis 37 from the outside, and although the range of rotation of the starter lever 28 is limited by the bushing 56 during the motor starting period that the sleeve 56 comes into contact with the charge pressure compensation lever 24 , the limiting element must have this shape. It is also possible, for example, to design the limiting element as a projecting part integrally with the starter lever 28 .

As disclosed in JP-A-59-101552, the wastegate known from the prior art is constructed such that it only depends on the axis M4 of the wastegate, in which way the wastegate lever with the rear surface of the tension lever 27th comes into contact. Therefore, it is, also because of certain restrictions in the structure of the starter lever 28, etc., not possible to arrange the contact position very far below. According to the invention, however, the contact surface 55 , which protrudes on the side, is designed by bending the un lower end part of the wastegate lever 24 in such a way that the contact surface 55 can come into contact with both the extended part 38 of the tension lever 27 and with the bushing 56 . Therefore, by moving the touch position downward, it is possible to increase the distance from the axis M4 of the wastegate lever 24 , and a large change in the amount of fuel to be injected can be caused by a small stroke of the wastegate lever 24 .

In addition, it is necessary in the charge pressure compensation lever known from the prior art to keep the contact point of the tension lever and the charge pressure compensation lever outside the attachment point of the centrifugal control spring. If, for example, the point of contact with the tension lever 27 is shifted upward to the right in FIG. 4, the centrifugal force spring 35 must be arranged further to the left. Therefore, in the prior art, it is necessary to use various wastegate levers depending on the arrangement position of the control lever, that is, one wastegate lever that comes into contact on the right and another one that comes into contact on the left side. Now, in contrast, according to the invention there is a structure in which the lower end of the charge pressure compensation lever 24 is bent to the side, it is no longer necessary to use different charge pressure compensation levers, regardless of where the centrifugal regulator spring 35 is arranged, so that a single one Boost pressure compensation lever 24 can be used.

As has already been described, spins during the initial stage the engine starting period of the starter lever and the tension lever in agreement mung and then when the boost pressure compensation lever towards an increase the amount of fuel to be injected is also turned area of the tension lever enlarged so that a force to be injected Amount of substance is achieved, which corresponds to the increase in charging pressure. At the same time, during the initial stage of the engine start-up period, the un dependent rotation of the starter lever by that arranged on the starter lever Bounding element limited to inject a too large increase in suppress the amount of fuel during the engine start-up period. While the correct amount of fuel to be injected during the engine startup period is maintained, it is nevertheless possible to behave to achieve the amount of fuel to be injected during the Operation at high speed a sufficient increase in the injection allows the amount of fuel.

Claims (5)

1. Fuel control system with a wastegate ( 15 ) for a fuel injection pump with a wastegate lever ( 24 ) pointing wastegate ( 15 ) and with a tension lever ( 27 ) and a starter lever ( 28 ) having a centrifugal force control mechanism ( 25 ), the wastegate lever ( 24 ) depending on an increase in the boost pressure in the direction of an increase in the amount of fuel to be injected, the starter lever ( 28 ) rotating during the engine starting period in accordance with the tension lever ( 27 ) and thereby the amount of fuel to be injected during the initial stage of the engine starting period by a independent rotation in the direction of an increase in the amount of fuel to be injected and wherein the rotation of the tension lever ( 27 ) in Rich direction of increasing the amount of fuel to be injected by touching the tension lever ( 27 ) with the boost pressure compensation lever ( 24 ) is characterized in that a limiting element ( 56 ) is arranged on the starter lever ( 28 ) and that the limiting element ( 56 ) limits the rotation of the starter lever ( 28 ) in the direction of increasing the amount of fuel to be injected in that the Bounding element comes into contact with the charge pressure compensation lever ( 24 ) during the initial stage of the engine start-up period. 2. Fuel control system according to claim 1, characterized in that the limiting element is a bushing ( 56 ) and that the bushing ( 56 ) is arranged on the outside on an on the starter lever ( 28 ) arranged axis ( 37 ). 3. Fuel control system according to one of claims 1 or 2, characterized in that the limiting element (sleeve 56 ) on a at the lower end of the boost pressure compensation lever ( 24 ) formed contact surface ( 55 ) comes to rest. 4. Fuel control system according to claim 3, characterized in that a part ( 38 ) of the tension lever ( 27 ) on the contact surface ( 55 ) of the charge pressure compensation lever ( 24 ) comes to rest. 5. Fuel control system according to one of claims 3 or 4, characterized in that the contact surface ( 55 ) on the charge pressure compensation lever ( 24 ) is formed by bending the lower end parallel to its bearing bush.