DE4041450A1 - Fuel injection pump for diesel engine - uses interruption valve to shift injection timing while idling - Google Patents

Abstract

The pump has a two-stage control cam (8) provided by a rotary cam disc (4) controlling the reciprocation of the pump piston (5). The fuel injection timing is adjusted by a regulator (38) when the engine is idling and the engine r.p.m. are within the bottom speed range. Pref., the fuel injection timing is adjusted via an interruption valve (37) used to close a coupling channel (30) extending through a regulating shaft (17) and communicating with a suction channel (B) for the fuel. ADVANTAGE - Higher fuel economy.

Description

The invention relates to a fuel injection pump for a Diesel engine, especially a fuel injection pump a two-stage control curve and a recess pointing delivery valve.

There is a problem with a special Ge in diesel engines Noise development when idling. As one of several counter measures took for a noise reduction shows one in one  Line built-in fuel injection pump a control curve with two different inclination ranges. This means, it is already a so-called two-stage control curve knows how in "Automobile Engineering Handbook (extended third edition) ". In addition, a ver Partial fuel injection pump with a two-stage control curve known.

For the two-stage distributor fuel injection pump Control curve is a control curve for moving one back and forth Plungers for supplying fuel under pressure in this way designed to form the following: an area with egg a small steering angle with a small increase and a Area with a large head angle with a large an rose.

On the other hand, the following method is also known. This be is that a small incision or recess is formed on a piston of a delivery valve such that a residual pressure in a fuel injection pipe is controlled becomes high at a low load condition, and the Residual pressure in the fuel injection pipe is controlled that it is low when the load is high.

As a result, fuel becomes excess in these control operations in tune with the small rise range, d. H. the low other control curve speed range of the control curve at idle condition injected. When a fuel injection timing is on controlled in this way becomes a fuel injection amount during an ignition delay phase decreased to a mode rate to achieve combustion, reducing the idle noise is reduced.

If the load on this fuel injection pump is increased, injection timing is due to a deceleration direction  of the control curve shape mentioned above. To avoid the injection timing shifted in the delay direction ben is a speed corresponding to the injection timing control device for shifting a fuel pressure feed start timings in the feed direction at higher speed intended. In addition to the corresponding speed Injection timing control device is still a load release appropriate injection timing control device for shifting the Fuel pressure supply starts in the feed direction at Motor load increase provided.

With the distributor fuel injection pump with the two-stage Control curve is due to the presence of the small off Take, which is formed on the piston of the delivery valve, the Residual pressure in the fuel injection pipe in a low Speed range higher and low in a high speed range riger. For this reason, fuel injection timing is used Increase in speed in the deceleration direction in combination shifted with the effect of the control curve shape. On the other hand with a low load condition, the size of the shift Exercise of fuel pressure start timing in feed direction by means of the load-corresponding injection timing control direction to turn out small. Accordingly, the Low load condition the fuel injection timing in at times Deceleration direction shifted when the engine speed increases takes and then in the feed direction when operating the speed corresponding injection timing control device in feed direction returned. The size of the shift in force fuel injection timing in the deceleration direction is great if the load is smaller. For this reason, at a load free state the fuel injection timing in deceleration direction shifted beyond a misfire limit, and misfires can occur.  

Such problems can arise in the same way in one Line installed fuel injection pump with a two stepped control curve and an incision Delivery valve occur.

Starting from the situation outlined above, the Er aims is looking for a fuel injection pump for one To make available diesel engine of the type mentioned at the beginning, where the fuel injection timing is in the no-load condition be prevented from decelerating at low speed can, due to the influence of one on the delivery valve formed recess would cause misfires.

According to the invention, this object is achieved by the claim 1 marked features solved.

Preferred features that advantageously further develop the invention these can be found in the subordinate claims.

Advantageously, the invention makes fuel injection pump for a diesel engine with a two-stage control curve and an incision or recess pointing delivery valve available, consisting of a Rege lungseinrichtung by which a load-free state of a Mo tors and the engine speed than within a low engine speed range can be determined falling; and one inevitably fig actuated angular feed device through which a force injection timing is inevitable when the Engine control device determines that the engine is in no load condition and the engine speed within of the low engine speed range falls.  

Further details, features and advantages of the invention are the subsequent description section, in which the Invention with reference to the accompanying drawings forth is explained, in which reference numerals diesel denote ben or similar parts. It shows

Figure 1 is a sectional view through the overall structure of a fuel injection pump for a diesel engine according to an embodiment of the invention.

FIG. 2 is a sectional view showing a structure of a hydraulic timer used in the hydraulic injection pump shown in FIG. 1;

Fig. 3A is a sectional view showing a structure of a delivery valve used in the fuel injection pump shown in Fig. 1;

Fig. 3B is a cross-sectional view taken along a section line IV-IV in Figure 3A by the delivery valve.

Fig. 4 is a graphical representation showing a control profile of a face cam, which is provided for the fuel injection pump of FIG. 1;

Fig. 5 is a graph showing the injection timing a Kraftstoffein; and

Fig. 6 is a cross-sectional view of a structure of a cold start device used in a fuel injection pump for a diesel engine according to another form of the invention.

The structure of a fuel injection pump according to an embodiment of the invention is described in more detail below with reference to FIGS. 1 to 5.

In Fig. 1, reference numeral A denotes a fuel injection pump (hereinafter simply referred to as a pump) according to this embodiment. The general structure and the operation of the pump A, the structure and the mode of operation in connection with a two-stage control and the structure and the mode of operation of the characteristic properties of the invention will be described below.

I. General structure and mode of operation of pump A

Since the structure of Pump A is known to experts, it is used in briefly described below.

I-1. Fuel intake and pressure supply operation

Fuel is sucked in from a (not shown) tank by means of a feed pump 2 , which is driven by a drive shaft 1 , which is connected to a crankshaft (not shown), and fed to a pump chamber 3 . At the same time, a face plate 4 and a plunger 5 are rotated by the drive shaft 1 . A plunger spring 6 presses the plunger 5 and the faceplate 4 against a roller 7 , the position of which is variable by means of a hydraulic timer 23 (to be described later).

When the drive shaft 1 is rotated, the Plankur vensscheibe 4 is rotated. If an upward inclination of a control profile 8 , which is formed on the surface of the face plate 4 , is acted upon by the roller 7 , the plunger 5 and the face plate 4 are set to the right in FIG. 1 against the prestressing force of the plunger spring 6 . This stroke movement of the plunger 5 is defined as an upward stroke. On the other hand, when a downward inclination of the control profile 8 is acted upon by the roller 7 , the plunger 5 and the face cam 4 are shifted to the left in FIG. 1. This stroke movement of the piston 5 is defined as a downward stroke.

A suction groove 10 and a distribution groove 12 are formed in the plunger 5 . The suction groove 10 communicates with egg nem feed hole 9 , which is only in connection with the pump chamber 3 during the downward stroke, ie the left stroke movement ( FIG. 1 of the plunger 5 ). The distribution groove 12 communicates with a distribution channel 11 only during the downward stroke, ie the right th stroke movement ( FIG. 1) of the plunger 5 .

During the downward stroke of the piston 5 , the volume of a pressure supply chamber 13 is increased. At this time, fuel is drawn from the pump chamber 3 toward the pressure supply chamber 13 via the supply hole 9 and the suction groove 10 . If the plunger 5 is rotated further from this state, a connection state between the feed hole 9 and the suction groove 10 is cut off and the distribution groove 12 communicates with the distribution channel 11 . When the plunger 5 is rotated further, the plunger 5 begins to move upward along the upward slope of the control profile of the face cam 4 , and a pressure supply operation for the fuel from the pressure supply chamber 13 to the distribution passage 11 via the distribution groove 12 is started.

When the plunger 5 is moved upward and a pilot hole or hole 14 of the plunger to the pump chamber 3 is open, high pressure fuel flows in the pressure supply chamber 13 into the pump chamber 3 , and the internal pressure of the pressure supply chamber 13 is reduced, whereby the fuel pressure supply operation is completed.

I-2 fuel distribution

In order to supply and distribute fuel to respective cylinders under pressure during one revolution of the plunger 5 , the face cam 4 has the same number of comb profiles 8 as the number of cylinders. The plunger 5 has the same number of suction grooves 10 as the number of cylinders and contains the same number of distribution channels as the number of cylinders. As a result, the plunger 5 repeatedly performs fuel intake and fuel pressure supply operations, the frequency corresponding to the number of cylinders during one revolution. More specifically, fuel is supplied under pressure from a distribution groove 12 via the associated distribution channel 11 .

I-3 fuel injection quantity control

The fuel injection amount is a product of the cross sectional area of the plunger and Druckzuführhub 5 defi ned, a stroke of the plunger 5 from the beginning of the Druckzuführbetriebs ie up to the end thereof. The pressure supply stroke can be changed by moving the position of a control ring 15 along the axial direction of the plunger 5 . Specifically, when the control ring 15 is moved to the left in Fig. 1, the pressure supply stroke decreases, and thereby the fuel injection amount decreases. If the control ring 15 is instead moved to the right in FIG. 1, the pressure supply stroke increases and as a result the fuel injection quantity is increased.

The position control of the control ring 15 and the control of the fuel injection quantity are carried out by means of a controller 16 .

The controller 16 is held by a controller shaft 17 and is arranged in a holder 18 which is rotated by the drive shaft 1 via gear wheels. The controller 16 be sits a centrifugal force weight 19 , which is displaced by the centrifugal force when the drive shaft 1 rotates in a direction indicated by an arrow X, a regulator sleeve 20 which corresponds to a rotation of the drive shaft 1 , ie an increase in the engine speed when the Fliehkraftge weight 19 in the X direction in Fig. 1 is moved to the right, and a regulator lever assembly 21 , which is in contact with the regulator sleeve 20 , which is clockwise around a lever pivot point M in the movement of the regulator sleeve 20 in an arrow Y specified direction is rotated, which is connected via a spring to an accelerator lever L, which is rotated when a gas pedal (not shown) is depressed, and which is rotated counterclockwise around the lever pivot point M when the accelerator pedal is never depressed.

The regulator lever assembly 21 and the control ring 15 are connected to each other via a ball joint 22 . When the controller 16 has the above-mentioned structure, when the amount of depression of the accelerator pedal becomes larger, that is, when the load becomes larger, the control ring 15 in FIG. 1 moves to the right and consequently the fuel injection amount increases. On the other hand, if the amount of depression of the accelerator pedal is constant when the engine speed increases, that is, when the load decreases, the control ring 15 is moved to the left in Fig. 1, and consequently the fuel injection amount is reduced.

I-4 fuel injection timing control

The structures and operations of the hydraulic timer 23 and a load sensing timer 39 for controlling the fuel injection timing will be described below.

I-4a Hydraulic timer

The fuel pressurized by pump A is fed under pressure to a fuel injector I through an injection pipe 32 . For this reason, there occurs a difference in the timing of the start of the pressure supply of the fuel in the injection pipe 23 and the timing of the start of the fuel injection from the fuel injector I, that is, a delay in the timing of the start of the fuel injection from the timing of the start of the pressure supply. The delay of the fuel injection timing compared to the pressure supply start timing is expressed by an angle, and the delay angle of the fuel injection timing is largely changed as the speed increases if the pressure supply start timing of the pump A is assumed to be constant. Accordingly, in order to make the fuel injection start timing constant, the pressure supply start timing must be set rather when the speed increases, and for this purpose the hydraulic timer 23 is provided.

The Druckzufuhrbeginntiming is defined by a timing at which the plunger 5 begins to move upward, that is, a timing at which the roller 7 begins to ramp up the upward inclination of the control profile of the face cam 4 . For this reason, the Druckzufuhrbe ginntiming can be controlled by changing the relative position of the roller 7 with respect to the control profile 8 along the circumferential direction of the face plate 4 .

The position change control of the roller 7 is carried out by the hy metallic timer 23 , which is integrated in the pump A. As shown in Fig. 2, the hydraulic timer 23 has a timer piston 24 which extends perpendicular to the drive shaft 1 along a direction. The timer piston 24 is slidably arranged in a cylinder 26 along its direction of extension. In the cylinder 26, an internal pressure of the pump chamber 3 for displacing the piston 24 to the left ( FIG. 2) acts on the right end surface ( FIG. 2) of the titanium piston 24 and a biasing force of a timer spring 25 for displacing the piston 24 to the right ( FIG. 2) acts on the left end face ( FIG. 2) of the timer piston 24 . As a result, the timer piston 24 slides in the cylinder 26 in accordance with a balance between the internal pressure of the pump chamber 3 and the pretensioning force of the timer spring 25 . When the piston 24 moves, a roller ring 28 for holding the rollers 7 is rotated via a slide pin 27 . When the roller ring 28 rotates , the relative position of the roller 7 with respect to the control profile 8 is changed.

When the speed of the pump A is increased and the internal pressure in the pump chamber 3 is increased, the piston 24 is moved to the left ( FIG. 2) in the cylinder 26 against the biasing force of the timer spring 25 and the roller ring 28 in the clockwise direction in FIG. 2 pivoted. The pivoting movement of the roller ring 28 in the clockwise direction is opposite to the direction of rotation of the drive shaft 1 , since the direction of the drive shaft 1 takes place in the counterclockwise direction, as indicated by an arrow in FIG. 2. This will advance the pressure start timing. On the other hand, when the speed of the pump A is decreased and the internal pressure of the pump chamber 3 decreases, the biasing force of the timer spring 25 overcomes the internal pressure. As a result, the timer piston 24 is moved to the right in FIG. 2 and the roller ring 28 is pivoted in the counterclockwise direction in FIG. 2. The counterclockwise Ver pivotal movement of the roller ring 28 takes place in the same direction as the direction of rotation of the drive shaft 1 and here by the Druckzufuhrbegommeniming is delayed.

I-4b load sensing timer 39

Generally, when fuel injection timing is advanced, output increases and noise increases accordingly. As a requirement from a vehicle side, an output from a high load state is considered important, while a low noise in a low or unloaded state is considered important. In order to meet such requirements, the Druckzuführbeginntiming must be shifted in a delay direction when the low or no load state, and at a high load state the Druckzu lead timing must be shifted in the advance direction. For this reason, the load sensing timer 39 is provided.

As shown in Fig. 1, the load sensing timer 39 is formed by opening 29 formed in the regulator sleeve 20 and a connec tion channel 30 which extends through the interior of the regulator shaft 17 and communicates with a fuel intake channel P.

When a load is reduced, the control ring 15 is moved in one direction in order to reduce the fuel injection quantity, ie the regulator sleeve 20 is moved to the right in FIG. 1 and the openings 29 of the regulator sleeve communicate with the connecting channel 30 in the regulator shaft 17 . As a result, fuel in the pump chamber 3 partially flows into the intake passage P, and the internal pressure of the pump chamber 3 is reduced. As a result, the biasing force of the timer spring 25 ( Fig. 2) overcomes the internal pressure of the pump chamber 3 , and the timer piston 24 is moved to the right in Fig. 2. As a result, the roller ring 28 is rotated in the same direction as the direction of rotation of the drive shaft 1 as indicated by an arrow in Fig. 2, and the pressure supply start timing is shifted in the deceleration direction. In this way, a low noise level can be ensured in the low-load state or in the no-load state.

On the other hand, if the load is increased and the control ring 15 is moved in a direction to increase the fuel injection quantity, ie the regulator sleeve 20 is moved to the left in FIG. 1, a connection between the openings 29 of the regulator sleeve 20 and the connecting channel 30 interrupted in the regulator shaft 17 . This increases the internal pressure in the pump chamber 3 and the timer piston 24 is moved to the left in FIG. 2. Accordingly, the roller ring 28 is pivoted in a direction opposite to the direction of rotation of the drive shaft 1 , and the Druckzufuhrbeginntiming is shifted in the leading direction. In this way, a high output can be guaranteed with a high load condition.

Even when the engine speed is constant, due to the operation of the load sensing timer 39 having the above-mentioned structure, the fuel injection timing can be advanced in the leading direction when a load increases.

I-5 Delivery valve 31

Fuel that is introduced into the distribution channel 11 by means of the pressure supply stroke of the plunger 5 opens a delivery valve 31 at a predetermined pressure and is introduced into the fuel injection pipe 32 under pressure. As shown in FIGS. 1 and 3A, the delivery valve 31 consists of a valve body 33 which is slidably arranged in the connecting end area of the distribution channel 11 along the axial direction, a valve seat 34 for interrupting a connection of the fuel from the distribution channel 11 to the fuel injection pipe 32 when the valve body 33 is brought into contact with them, and to produce a connection for the fuel Ver when the valve body 33 is spaced from the sem and from a valve spring 35 for the pre-tensioning of the valve body 33 in one Direction for contacting the valve seat 34 . When the pressure of the fuel is wel cher introduced under pressure into the distribution channel 11, overcomes the entire action of the biasing force of the valve spring 35 and the residual pressure remaining in the injection pipe 32 fuel, the fuel can be a spacing of the valve body 33 from the valve seat 34 for Open För derventils 31 cause and inserted into the fuel injection pipe 32 .

If the plunger 5 is moved further upwards and the injection stroke is near its end, the pressure in the plunger 5 , ie the distribution channel 11 , is immediately reduced. As a result, the biasing force of the valve spring 35 prevails and the valve body 33 is pressed against the valve seat 34 in order to close the delivery valve 31 in this way. Accordingly, the front valve 31 has a function to prevent a reverse flow of the fuel during the suction stroke of the plunger 5 , and to keep the fuel in the fuel injection pipe 32 at a residual pressure, thereby avoiding an injection delay.

A piston 36 having an outer surface that is slidably slidable along an inner surface of the distribution passage 11 is integrally formed at the center of the valve body 33 . Due to the provision of the piston 36 , fuel is drawn into the fuel injection pipe 32 in a volume size that corresponds to a stroke movement from a state in which the valve seat 34 surrounds the piston 36 when the fuel injection changes until the valve body 33 is completely on the valve seat 34 sits. The pressure in the fuel injection pipe 32 is excessively reduced by the amount of fuel drawn in, and the nozzle I can satisfactorily be turned off immediately after the fuel injection operation.

I-6 fuel injector

When the fuel introduced under pressure into the fuel injection pipe 32 via the delivery valve 31 reaches a predetermined pressure, it is injected into an associated cylinder of the engine via the injection nozzle I. The structure of the injector I is known to those skilled in the art and its description is omitted here.

II. Structure and mode of operation of the two-stage control curve and assigned sections

Because the two-stage control curve and its associated section te are known to the experts, they are only below briefly described.

The faceplate 4 is designed as a two-stage control curve such that each control profile 8 has an area that has a small control angle as area 8 a with a slight increase in inclination (upward or downward inclination) and an area 8 b that has a large one Control angle as a region with a large increase, as shown in Fig. 4.

A small flat 36 a is formed on the outer circumference of the piston 36 of the delivery valve 31 , as shown in FIGS . 3A and 3B. Since the flattening 36 a is provided, a fuel pressure supply process can be continued via the flattening 37 a in a low-rig area or free-load area with a small amount of fuel injection. Accordingly, a flow rate of the valve body 33 , ie the piston 36 , is reduced ver. In this way, the draw-in quantity is reduced when the fuel injection process is completed and the residual pressure in the fuel injection pipe 32 is increased accordingly. On the other hand, since the effect of the flattening 36 is lost in a load area with a large fuel injection quantity, the delivery quantity of the valve body 33 , ie the piston 36 , is increased. In this way, the intake quantity can be increased when the fuel injection process is completed and the residual pressure in the fuel injection pipe 32 can be reduced accordingly.

Is in the low load region and no-load region since the size of the upward movement of the plunger 5, the erfor for an increase of the fuel pressure until the next injection stroke is sary, reduced, as a result, a fuel injection operation performed a of the control section 8 in the small increase range. 8 Since this region 8 a corresponds to a region with a low cam speed, the fuel injection quantity can be reduced during an ignition delay phase. This enables the combustion to be moderate and the noise level to be reduced when idling.

Since the size of the upward movement of the plunger 5 , which is required to increase a fuel pressure up to the next injection stroke, is increased in a high-load area, the fuel injection process is carried out in the large rise area 8 b of the control profile 8 . Since this area 8 b corresponds to an area with a high cam speed, a sufficient fuel injection quantity can be ensured and, consequently, a sufficient output power can be guaranteed in the high load condition.

III. Structure and mode of operation of characteristic features of invention

III-1 As already described in section II, the two-stage control curve is designed as a cam cam 4 in the pump A of this embodiment to reduce the idle noise, and the small flattened portion 36 a is formed on the piston 36 of the delivery valve 31 . In this way, the residual pressure in the fuel injection pipe 32 is increased in a low-load area or load-free area with a small fuel injection amount, while in a high-load area, the residual pressure in the fuel injection pipe 32 is reduced in a large fuel injection amount.

If a load is constant, the fuel through the flattening 36 a can remain under pressure in a low speed range, and a pressure supply process of the fuel through the flattening 36 a is suppressed in a high speed range. As a result, the flattening 36 a has the function of maintaining a high residual pressure in the fuel injection pipe 32 in the low speed range and the low pressure in the fuel injection pipe 32 in the high speed range. If there is a constant load as the engine speed increases, the fuel injection timing is consequently shifted from the small rise area 8 a to the large rise area 8 b of the faceplate 4 , thereby delaying the fuel injection timing.

On the other hand, when the engine speed is increased, the pressure supply start timing of the fuel is advanced by the hydraulic timer 23 . The pressure supply starts timing of the fuel is also advanced by the load sensing timer 39 . The size of the advance of the pressure supply start timing is large in a high load condition, but small in a low load condition. If the engine speed is increased, the fuel injection timing is temporarily shifted as a result in the deceleration direction and then returned in the leading direction by the mutual effect of the small flattening 36 a of the piston 36 of the conveyor valve 31 , the hydraulic timer 23 and the load sensing timer 39 .

The amount of movement in the deceleration direction is increased when the load is lower. Accordingly, in a no-load state, as shown by a solid curve in FIG. 5, fuel injection timing in the deceleration direction can be shifted beyond a misfire limit in a specific low speed range, for example in a range of 1000 to 1800 rpm.

In order to prevent misfires in the no-load state, in this embodiment, a valve 37 is arranged to interrupt the operation of the load sensing timer 39 such that the fuel injection timing is advanced in the above-mentioned specific speed range.

III-2 Load sensing cutoff valve 37

The Lastabfühlunterbrechungsventil 37 is inserted midway along the connecting channel 30 so that it closes the Verbin dung channel 30 which forms in the spe-specific low-speed range the Lastabfühltimer 39, and makes the operation of the Lastabfühltimers. 39 The cut valve 37 closes the communication channel 30 when it receives an ON signal and opens the channel 30 when it OFF signal he holds a. A control unit 38 for controlling the interruption valve 37 is provided.

The control unit 38 has a CPU, a RAM and a ROM. The control unit 38 receives various types of detection signals, in particular an accelerator opening size signal with gas opening size information from a gas opening size sensor (not shown), and an engine speed signal with engine speed information from an engine speed sensor (not shown), which are assigned to the interruption valve 37 of this embodiment. On the other hand, the control unit 38 supplies a control signal including the above-mentioned ON / OFF signal to the cut valve 37 .

More specifically, the control unit 38 detects the load condition and the engine speed of the engine based on the accelerator opening amount signal and the engine speed signal. When the control unit 38 determines that the engine is in a no-load state and the engine speed is close to the above-mentioned specific low speed range, that is, when the engine state is close to a misfire range, it outputs the ON signal to the cut valve 37 . Upon receipt of the ON signal, the interrupt signal 37 closes the connection channel 30 of the load sensing timer 39 . As a result, the load sensing timer 39 is stopped.

When the load sensing timer 39 is stopped, the internal pressure in the pump chamber 3 is increased and the fuel injection timing is advanced due to the operation of the hydraulic timer 23 , as indicated by a broken line in FIG. 5. Misfires can thus be effectively avoided.

The illustrated invention is not based on the structure of the above Limited embodiment. Rather, they can be different changes and modifications within the scope of protection be made of the invention.

For example, in the above embodiment, for the inevitable advancement of the fuel injection timing (to inevitably perform an angular advance) in a specific low speed range, the interruption valve 37 is provided for stopping the load sensing timer 39 . However, the invention is not limited to this structure. In example, as shown in Fig. 6 as a further embodiment, in a diesel engine having a Kaltstartvor direction (hereinafter referred to as CSD), the CSD is forced to operate in an angular advance direction in order to inevitably advance the fuel injection timing (inevitably an angle advance operation perform).

The structure of this embodiment is described below with reference to FIG. 6. Here, the same reference numerals in this embodiment denote the same parts as in the above embodiment, and a detailed description thereof is therefore omitted.

Referring to FIG. 6 28 comprises a roller ring on a hydraulic timer 23 for setting a fuel injection timing of a pump, a timer A shaft 40 for integral rotation of the ring 28. In this embodiment, if the timer shaft 40 is pivoted clockwise in FIG. 6, the fuel injection timing is moved in the advance direction, ie an angular advance process is achieved. When the timer shaft 40 is pivoted counterclockwise, the fuel injection timing is shifted in the decelerating direction, that is, an angular decelerating operation is achieved as in the above-mentioned embodiment.

In this embodiment, a CSD 41 has an actuation lever 43 , which is always integrally mounted on the timer shaft 40 for pivoting and is biased in the direction of an angle feed side by means of a spring 42 . When the operating lever 43 is pivoted, the angular advance process of the fuel injection timing of the pump A can be achieved.

The CSD 41 has a sleeve 45 to the side of the actuating lever 43 . The inside of the sleeve 45 is provided as a coolant chamber 44 through which an engine coolant flows. The sleeve 45 has an open end portion which lies opposite the actuating lever 43 . A cylinder member 46 is slidably housed in the open end portion of the sleeve 45 . More specifically, the above-mentioned coolant chamber 44 is formed in the sleeve 45 by means of the inner space of the sleeve 45 , which is closed by the cylinder member 46 .

A thermo-wax 47 which expands when the temperature increases of the fluid flowing through the coolant chamber 44 engine coolant is housed in the coolant chamber 44th A piston 49 is slidably mounted in a cylinder chamber 48 which is formed in the cylinder element 46 . A piston rod 50 is integrally formed on the piston 49 protruding outwards, ie in the direction of the actuating lever 43 . The distal end of the piston rod 50 is provided as actuating element 50 a of the actuating lever 43 . Be the actuating lever 43 always touches the distal end of the actuating element 50 a due to the biasing force of the spring 43rd

A connecting passage 51 is formed in the cylinder member 46 extending along the axial direction thereof. The inner end of the communication passage 51 communicates with the cylinder chamber 48 , and its outer end is connected to the distal end portion of an oil connection pipe 52 . The proximal end portion of the oil connection pipe 52 is arranged inside an oil pan 53 for receiving the engine oil. The suction pipe from the oil pan 53 by means of an oil pump 54 , which is arranged in the middle along the oil pipe 52 , engine oil is introduced into the cylinder chamber 48 at a predetermined pressure through the oil connection pipe 52 . This means that the piston 49 protrudes outward due to the engine oil introduced into the cylinder chamber 48 , as shown in FIG. 6.

A switching valve 55 through which the engine oil in the Zylinderkam mer 48 insertable or not insertable, is in a section from the oil connection pipe 52 downstream of the oil pump 44 interposed. The switching valve 55 can be switched between a connection position in which the oil pump 54 communicates with the cylinder chamber 48 , and a switch-off position for connecting the oil pump 54 to the oil pan 53 using an electromagnetic rotary solenoid 56 as a drive source, although it is only shown in a simple manner.

The driving operation of the electromagnetic rotary solenoid 56 , that is, a switching operation of the switching valve is controlled by the same control unit 38 as in the above embodiment. More specifically, the control unit 38 supplies when the engine is in a no-load state and the engine speed is within an operating range other than that above mentioned special low speed range falls, a control signal to the electromagnetic rotary solenoid 56 to set the switching valve 55 in the open position. When the switching valve 55 is in the open position in this way, the engine oil is due to the operation of the oil pump 54 through the oil connection pipe 52 into the cylinder chamber 48 and the piston rod 50 protrudes toward the actuating lever 43 before.

The size of the protrusion of the piston rod 50 is such that the operating lever 43 , which touches the distal end of the piston rod 50 , is arranged on the side of the largest Winkelvor while the thermal wax 47 is kept cold th. More specifically, when the engine is cold, the thermal wax 47 is not heated by the coolant and does not expand. As a result, the fuel injection timing in the pump A is set to an angular advance side. When the engine is started and the engine continues to run, the coolant is gradually heated. When the coolant is heated, the thermal wax 47 gradually expands. When the thermal wax 47 extends, the cylinder element 46 protrudes in the direction of the actuating lever 43 and as a result the actuating lever 43 , which contacts the actuating element 50 a of the distal end of the piston rod 50 , which is mounted on the cylinder element 46 , gradually in the direction moved to an angular deceleration side. In this way, when the engine temperature rises, the fuel injection timing of pump A is shifted in the deceleration direction.

As a characteristic feature of this embodiment, when the control unit 38 determines that the engine is in a no-load state and an engine speed is close to the above-mentioned specific low speed range as described in the above embodiment, the control unit 38 supplies a control signal to the electromagnetic rotary solenoid 56 . to set the switching valve 55 in the interruption position such that the pump A inevitably performs an angular advance process, in other words, the actuating lever 43 is inevitably pivoted to the angular advance side. In this way, when the switching valve 55 is switched from the connection position to the open position, the supply of the engine oil to the cylinder chamber 48 is stopped. As a result, a force for pushing the piston rod outward disappears. As a result, the piston rod 50 (ie, the piston 49 ) is retracted into the cylinder chamber 48 due to the biasing force of the spring 42 acting on the operating lever 43 , and the operating lever 43 is pivoted to the angular advance side. When the CSD 41 is set in a state in which the thermal wax 47 expands due to the heated coolant and the operating lever 43 is pivoted to the angular delay side, the piston rod 50 is pulled inward such that the fuel injection timing of the pump A is inevitably pushed towards the angular advance side. Even when an engine condition is close to a misfire area, misfires can be reliably prevented.

As described above, according to the exemplary embodiment shown in FIG. 6, the cylinder element 46 , the piston 49 , the piston rod 50 , the oil connection pipe 52 , the oil pump 54 , the switching valve 55 and the electromagnetic rotary solenoid 56 form an angular advance mechanism 57 as an inevitable angular advance device. Since the angle feed mechanism 57 is used in the above-mentioned structure when the engine is in a no-load state and the engine speed is set near the above-mentioned specific low speed range, the fuel injection timing of the pump A becomes inevitable to the angle feed side as in the above embodiment shifted and misfires can be reliably prevented.

In the embodiment shown in Fig. 6, the Win kelvorschub Mechanism 57 is formed by the cylinder element, the piston ben 49 , the piston rod 50 , the oil connection pipe 52 , the oil pump 54 , the switching valve 55 and the electromagnetic rotary lenoid 56 in the CSD 41 . However, the invention is not limited to this structure. The angle feed mechanism 57 can often have other structures as long as it inevitably shifts fuel injection timing to an angle feed side based on a control signal from the control unit 38 .

Claims (8)

1. Fuel injection pump for a diesel engine with a two-stage control cam ( 8 ) and a delivery valve ( 31 ) having a recess, characterized by :
a control device ( 38 ) by which a load-free state of an engine and the engine speed can be determined as falling within a low engine speed range; and
a positively actuated angle feed device ( 37 ) or ( 57 ) through which a fuel injection timing is inevitable when the engine control device ( 38 ) determines that the engine is in the no-load state and the engine speed falls within the low engine speed range. 2. Pump according to claim 1, characterized in that a load sensing timer ( 39 ) is provided, through which a pressure feed start timing of the fuel at a low load state of the engine in a deceleration direction and the pressure feed start timing in a feed direction can be pushed ver, and that the inevitably operated Angle feed device has an interruption valve ( 37 ) for holding the load sensing timer ( 39 ). 3. Pump according to claim 2, characterized in that the load sensing timer ( 39 ) through openings ( 29 ) which are formed in a regulator sleeve ( 20 ), and a Verbindungska channel ( 30 ) is formed, which extends through the interior of a regulator shaft ( 17 ) extends and communicates with a suction channel (B) for the fuel. 4. A pump according to claim 3, characterized in that the cut-off valve (37) is inserted in a central portion of the connecting channel (30) for closing the connecting channel (30), and in that by closing of the connecting channel (30), the fuel injection timing before slidably . 5. Pump according to claim 1, characterized by a cold starting device ( 41 ), by which when starting the engine in a cold state, the fuel injection timing is adjustable to an angle feed side, the positively actuated angle feed device having an angle feed mechanism ( 57 ) through which the cold start device is caused to shift the fuel injection timing to the angle feed side, even when the engine is idling. 6. Pump according to claim 2, characterized in that a roller ring ( 28 ) of a hydraulic timer ( 23 ) for setting the fuel injection timing of the fuel injection pump has a timer shaft ( 40 ) for the one-piece rotation of the roller ring ( 28 ) and that the cold starting device ( 41 ) a thermal wax ( 47 ) which expands by heat from a coolant, an actuating lever ( 43 ) which is rotatable in one piece with the timer shaft ( 40 ), and has a spring ( 42 ) through which the actuating lever ( 43 ) can be swiveled and pretensioned to an angle feed side. 7. Pump according to claim 6, characterized in that the angle feed mechanism ( 57 ) is an actuating element ( 50 a), which rests on the actuating lever ( 43 ) and the actuating lever ( 43 ) moves to an angular delay side when the thermal wax ( 47 ) expands, one hy draulic mechanism ( 46 , 48 , 50 , 51 , 52 , 54 ) for advancing the actuator ( 50 a) to the angular delay side by means of a hydraulic pressure, and a mechanism ( 50 , 56 ) for removing the hydraulic pressure, is done by the actuation of the element (50 a) acting hydraulic pressure canceled and the actuating element (50) is movable such that displacement of the actuating lever (43) to the thrust side Winkelvor. 8. Pump according to claim 7, characterized in that be tens of the hydraulic mechanism, the actuating element ( 50 a) can be advanced by engine oil.