JPS6025611B2 - Diesel engine cylinder fuel injection system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a valve-controlled fuel pump has a pump cylinder having a plunger and an overflow valve for regulating the start of pressure feeding, and the plunger is driven by a control shaft via a drive mechanism. The invention relates to an injection device for a cylinder of a diesel engine, in which the main body of the intake valve can be driven by the drive mechanism via a control lever that is swingable about a swing axis by the drive mechanism.

This type of valve-controlled fuel pump is covered by Swiss Patent No.
No. 89707.

The valve is usually arranged in a pump body with a through hole that guides a pump piston, called a plunger. A pressure chamber is formed in the pump body, and this pressure chamber is connected to a pressure feeding pipe leading to an injection valve via a pressure valve. The suction valve is arranged in the inlet flow path of the pump body connected to the supply pipe. The overflow valve controls the flow rate of fuel in an overflow path of the pump body connected to the overflow pipe. The plunger is driven via a cam on the control shaft and a drive piston which controls the valve body of the intake valve and the valve body of the overflow valve via one control lever each.

The control lever of the overflow valve is often arranged swingably on the eccentric of the eccentric marrow, so that the pivot axis of the control lever can be displaced about its main axis by rotation of the eccentric marrow. This makes it possible to change the stroke of the overflow valve and thus the end of pumping and the pumping amount. The eccentric shaft can in this case be coupled to a speed regulator of the engine, so that the pumping quantity is controlled as a function of the load during the entire operating period. A control lever for driving the intake valve is arranged in relation to the working piston so as to be able to swing freely about a fixed oscillating axis and such that the start of fuel injection occurs a predetermined time before the top dead center of the working piston. High-power diesel engines require a large amount of fuel even in the part-load region.

This amount of fuel is injected earlier than conventionally for thermodynamic reasons, in order to comply with demands for improved fuel consumption as well as stricter exhaust gas specifications. If the injection and ignition timings are advanced, the cold start behavior of the engine will be adversely affected by sharp combustion noises, i.e. severe rocking. Additionally, the steep pressure gradients and large peak pressures associated with knocking during combustion create significant stress on the engine's transmission mechanism. The object of the present invention is to provide a fuel injection system of the above-mentioned type, in which the start of pumping can be adjusted to temporarily delay the start of pumping during the starting operation, and then switched to an adjustment that causes the start of pumping to be earlier, which is advantageous for steady operation. The goal is to provide equipment.

In order to solve this problem, the fuel injection device according to the present invention switches the pump operation to the starting operation, switches the pump operation again to the normal operation after a predetermined starting operation time has elapsed, and starts pumping during the starting operation to the normal operation. This switching device has a switching device whose eccentric line is firmly connected to an eccentric shaft that is the swing axis of the control lever, and the switching device has a switching device whose eccentric line is firmly connected to an eccentric shaft that is the swing axis of the control lever, a lever swingable between two end positions, one of these two end positions being the normal operating position, the intake valve stroke causing the start of pumping during normal operation; Corresponding to the angular position,
The other end position is a starting operating position, in which the intake valve stroke corresponds to the angular position of the eccentric causing the initiation of starting pumping; , a setting device for respectively swinging the above-mentioned bars to the above-mentioned normal operating position in the return stroke, an adjustment mechanism for adjusting the above-mentioned normal operating position of the above-mentioned bars, and the above-mentioned starting operating position of the above-mentioned bars. The present invention is characterized in that it further includes an adjustment mechanism for adjusting the time, and a control device that operates the setting device in conjunction with a timer that monitors the starting operation time. The invention provides the advantage that the starting operation can be carried out in such a way that a delay adjustment of the pumping start and thus of the ignition timing takes place during the warm-up period of the engine.

As a result, steep pressure gradients and large light head pressures during combustion, which would otherwise occur at high outputs, and the associated knocking and large stresses in the engine transmission system can be avoided.
However, the early ignition timing and associated benefits during normal operation are retained. Further, the fuel injection device of the present invention includes:
It has a simple structure, is inexpensive, operates reliably, and can be modified in various ways, so it can be adapted to a wide variety of structures and uses without problems. According to a preferred embodiment of the invention, the setting device has a piston-cylinder unit actuated by a pressure medium, and the adjusting device for adjusting the starting actuation position of the lever comprises an actuator of the piston of the piston-cylinder unit. The adjusting device for adjusting the normal operating position of the lever consists of a stop that limits the return stroke of the piston.

The piston-cylinder unit may be pneumatic or hydraulic. In large diesel engines, such as marine diesel engines and stationary diesel power plants, pneumatic units are advantageous because they are easy to integrate into the engine's remote pneumatic control system.
The end position of the lever can be set by means of a stop, in which case it is advantageous if the stop can be displaced within relatively large limits. This makes it easy to change the end position of the lever, and therefore the start of pumping, both during starting operation and during normal operation. It is particularly advantageous to use a discharge device as a timer, which can have a throttle, a valve, a slider or a throttle, which discharges the working medium from the pressure chamber of the piston-cylinder unit in the starting operating position.

This evacuation begins at the beginning of the starting operation and continues at the following rates throughout this operating condition: This speed is the speed at which the pressure in the pressure chamber of the piston-cylinder unit increases after a predetermined start-up period until the force acting on the pressure chamber side of the piston is less than the spring force of the return spring acting on the other side of the piston. The speed is such that it decreases. This causes the piston to perform a return stroke and the lever to return to its normal operating position. A device can be provided which acts on the timer to change the start-up period. The device may be configured to calculate the start timing according to engine temperature, engine load, fuel quality, and other instantaneous operating parameters, thereby optimizing the starting operation by adapting it to the current conditions. becomes possible. The control device preferably has a control valve, which can be moved from a normal position to a starting position via a starting signal. In the starting position, this control valve establishes a connection between the pressure source and the pressure chamber of the piston-cylinder unit, so that the pressure chamber is rapidly pressurized. When the start signal is interrupted, the control valve automatically returns to its normal position, in which it drives the pressurized pressure chamber of the piston-cylinder unit to the ejector to begin evacuation, and remains in this position until the next start signal. stays in place. The starting signal acts on the control valve either automatically upon engine starting or by manual operation of a starting member independent of engine starting. The control valve may be an electromagnetically or pneumatically operated control valve. Next, preferred embodiments of the present invention shown in the drawings will be described in detail. The fuel pump shown in FIG. 1 includes a pump body 1, a pressure chamber 2 formed in the pump body 1, a suction valve 3, an overflow valve 4, and a pressure valve 5.

The suction valve 3 has an inlet flow path 6 connected to a supply pipe (not shown).
Inside, the overflow valve 4 is disposed in an overflow channel 7 connected to an overflow pipe (not shown), and the pressure valve 5 is disposed in an outlet channel 8 connected to a pressure pipe (not shown). This leads to a fuel injection valve (not shown). Plunger 9
is disposed in a through hole of the pump main body 1 formed in the mariline direction of the pressure valve 5 so as to be movable against the spring force of the coil spring. The plunger 9 is driven via a control shaft 10 with a cam 10', a trochanter 11 and a drive piston 12. The drive piston 12 further includes a control lever 15 and a ram 1.
6 to the valve body 13 of the suction valve 3, and the control lever 1
7 and ram 18 to drive the valve body of the overflow valve 4, respectively. The control lever 17 is swingably disposed on an eccentric wheel 19 of an eccentric shaft 20 in a manner not shown, and the eccentric spinal cord 20 is controllably connected to a rotation speed regulator (not shown) via a linkage 21. When the eccentric shaft 20 rotates around its main axis, the axis of the eccentric and thus the axis of oscillation of the control lever 17 is displaced, thereby changing the stroke setting of the overflow valve 4 and thus the end of pumping and the pumping amount of the fuel pump. . In this way, the pumping rate is controlled as a function of the load throughout the entire operating period. The control lever 15 is swingably disposed on the mercenary ring 22 of the eccentric shaft 23, and when the eccentric shaft 23 rotates around its main axis, the swing axis of the control lever 15 is displaced and At the same time, the stroke setting of the suction valve 3 and thus the start of pumping is changed.

A lever 24 firmly connected to the eccentric shaft 23
It swings between two final positions 24N and 24s around the main track line. The end position 24N is the normal operating position and corresponds to the angular position of the eccentric 22 at which the intake valve stroke causes the start of pumping during normal operation, whereas the end position 243 is the starting operating position and the intake valve stroke during start-up occurs. corresponds to the angular position of the eccentricity 22 that causes the start of pumping. The lever 24 is connected to a setting mechanism 25, which moves the lever 24 from the normal operating position 24N to the starting operating position 24s during the working stroke, and from the starting operating position 24s to the normal operating position 24N during the return stroke. Move the lever 24 to .

Final position 24N, 24 of lever 24 confirmed by calculation
The setting device 25 is synchronized to the setting device 25 by two adjustment mechanisms 26 and 27, of which the adjustment mechanism 26 is used to adjust the starting operating position 24s, and the adjusting mechanism 27 is used to adjust the normal operating position 24N. . The adjustment mechanism can be varied within certain limits. The setting handle 25 is also connected to a control device 28 which sends out control signals S^, SR for its work stroke and return stroke.

The timer 29, in conjunction with the control device 28, emits a signal SD after the desired start-up period has elapsed, which causes a return or reset signal SR to be emitted. A signal S is sent to the control device 28 (this may be a signal that is automatically generated when the engine is started, or a signal that is generated by manually turning on the signal source).
When is applied, the working process of the setting device 25 is started,
The lever 24 is brought into its starting operating position 243.

The signal S is also supplied at the same time to a timer 29, which starts measuring the starting actuation time and outputs the signal S after the desired starting actuation time has elapsed. The control device 28 sends a reset signal SR to the setting device 25 and starts the return stroke, so that the swing lever 24 is returned to its normal operating position 24N. To change the starting operation time,
A changing device 30 in conjunction with a timer 29 can also be used.

The change device 3 receives operational parameters defining the instantaneous state of the engine, such as engine temperature, instantaneous load of the engine or quality of fuel, calculates the time of starting operation from these parameters, and It may also have a function of sending the signal So to the timer 29 in the form of a signal So. 2 and 3 show a piston using air as a working medium as a setting device corresponding to the setting device 25 in FIG.
Cylinder unit 31 and control device 2 in FIG.
8, a pneumatic control valve 35 as a control device, and a first
As a timer corresponding to timer 29 in the figure,
FIG. 4 shows a discharge device 41 with a variable outlet cross section.

The IJ link device, which consists of two mutually pivotal plates 33 and 34, directs the movement of the piston rod of the unit 31 to the lever 2.
4 (not shown in FIGS. 2 and 3).

A stop 36 consisting of two nuts and movable on the piston rod 32 serves to limit the working stroke of the piston 37 towards the right in the figure and thus to set the starting operating position 24s of the lever 24.

A second internally threaded unit that is movable in the axial direction of the unit 31.
The stopper 38 is fixed with respect to the unit 31 by a nut 39. The second stopper 38 serves to limit the return stroke to the left in the figure and to set the normal operating position 24N of the lever 24. The control valve 35 as the control device 28 is in the normal position in FIG.
In the figures, each is shown in the starting position.

In the normal position, the control valve 35 connects the pressurized pressure chamber 40 of the unit 31 to the discharge device 41 via a pipe 48, and in the starting position, connects the pressure chamber 40 to a pressure source (not shown) via a pipe 42. . Control valve 35 can be moved from the normal position to the starting position via a starting signal S applied via line 43 either automatically or manually via pushbutton 44 .
In the starting position of the control valve 35, the pressure chamber 40 is rapidly pressurized, the piston 37 performs a working stroke limited by the stopper 36, and at the same time the lever 24 is moved into the starting operating position 2.
43. At this time, air on the other side of the piston 37 is exhausted from the exhaust hole 47 of the unit 31. When the starting signal S is interrupted, the control valve 35 returns to its normal position by means of its return spring 46, in which the evacuation device 4
1, the pressure chamber 40 slowly cools down, and the pressure in the pressure chamber 40 gradually decreases as a result. The outflow cross-sectional area of the ejector 41 is set such that the pressure increases until the force exerted on the piston 37 from the pressure chamber 40 side becomes smaller than the force exerted on the other side of the piston 37 by the return spring 46 after the elapse of the desired starting operation time. The pressure in the chamber 40 is set to a value that decreases. Piston 37 therefore performs a return stroke and returns to the normal operating position of FIG. 2, and at the same time lever 24 reaches its normal operating position 24N. According to an advantageous variant of the invention, an electromagnet or a servomotor with a linearly displaceable magnetic core can be used as the setting device 25.

In this case, the control device 28, the timer 29 and the displacement device 3
0 is an electrical or electronic device, in which some mechanical input quantities, such as the time setting of the drive piston 12, are input as electrical signals.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a valve-controlled fuel pump with a switching device represented as a block diagram, and FIG. 2 is a sectional view showing a piston-cylinder unit as a setting device and a control valve and a timer as a control device. FIG. 3 is a schematic representation of the switching device of FIG. 2 in the starting operating position; FIG. Explanation of symbols, 3...Intake valve, 9...Plunger, 10...Control shaft, 12...Drive piston, 15...Control lever, 22...
・Eccentric wheel, 23...Eccentric shaft, 24...Lever, 24s...Start operation position (final position), 24
N...Normal operating position, 25...Setting device,
26, 27...adjustment mechanism, 28...control device, 29...timer. Pirate map N Ship map

Claims (1)

[Claims] 1. A valve-controlled fuel pump has a pump cylinder equipped with a plunger, a suction valve that defines the start of pressure delivery, and an overflow valve that defines the end of pressure delivery, and the plunger is connected to a control shaft via a drive mechanism. The main body of the suction valve is driven by
In the drive mechanism, which is driven by the drive mechanism through a control lever that is swingable around the swing axis, the pump operation is switched to the starting operation, and after a predetermined starting operation time has elapsed, the pump operation is changed to the normal pump operation. It has a switching device that re-switches to the operation and makes the start of pumping during the starting operation different from the start of pumping during normal operation. Axis 23
is rigidly connected to the eccentric shaft 23 and has two end positions 24_N, 24_S around the main axis of this eccentric shaft.
a lever 24 which can be swung between the two end positions, one of which is a normal operating position 24_N;
The inlet valve stroke corresponds to the angular position of the eccentric 22 that causes the start of pumping during normal operation, and the other end position 24_S is the start-up position of the eccentric 22 where the intake valve stroke causes the start-up start of pumping. In addition, the switching device includes a setting device 25 for swinging the lever 24 to the starting operating position in the working stroke and to the normal operating position in the return stroke;
control for operating the setting device 25 in conjunction with an adjustment mechanism 27 for adjusting the normal operation position of No. 4, an adjustment mechanism 26 for adjusting the start operation position of the lever 24, and a timer 29 for monitoring the start operation time; A fuel injection device for a cylinder of a diesel engine, further comprising a device 28. 2. The adjusting mechanism 26 is displaceable for adjusting the starting operating position of the lever 24, and the adjusting mechanism 27 is displaceable for adjusting the normal operating position 24_N of the lever 24. A fuel injection device for a diesel engine cylinder according to scope 1. 3 that the setting device 25 has a piston-cylinder unit 31 actuated by a pressure medium and that the lever 24
The adjusting device 26 for adjusting the starting operating position of the unit 31 consists of a stopper 36 for limiting the working stroke of the piston 37 of the unit 31, and the adjusting mechanism 27 for adjusting the normal operating position of the lever 24 limits the working stroke of the piston 37. 3. A fuel injection device for a cylinder of a diesel engine as claimed in claim 1, characterized in that it comprises a limiting stopper (38). 4 The timer 29 is connected to the piston-cylinder unit 31
A fuel injection device for a cylinder of a diesel engine according to claim 1 or 3, characterized in that it has a pressure medium discharge device (41) that can be connected to a pressure medium discharge device (41) that can be connected to a pressure medium discharge device (41). 5. The control device 28 has a control valve 31 which establishes communication between the pressure chamber 40 of the piston-cylinder unit 31 and the pressure source and normally moves it towards a starting position in which the pressure chamber 40 is rapidly pressurized. The control valve 35 can be moved from the starting position via the starting signal S towards the normal position in which the control valve 35 establishes communication between the pressurized pressure chamber 40 and the evacuation device 41 and introduces the evacuation process. 5. The fuel injection device for a cylinder of a diesel engine according to claim 4, wherein the fuel injection device automatically returns to its original position when the engine is shut off, and remains in this normal position until the next starting signal S is received. 6. The fuel injection system for a cylinder of a diesel engine according to claim 5, wherein the starting signal S is a pressure signal, and is automatically applied to the control valve 35 at the same time as the engine is started. 7. The fuel injection device for a cylinder of a diesel engine according to claim 5, characterized in that the starting signal S can be supplied to the control valve 35 by manual operation of the starting member 44. 8. The fuel injection device for a cylinder of a diesel engine according to claim 4, wherein the outflow cross-sectional area of the exhaust device 41 can be adjusted in consideration of a desired start-up operation time. 9. A fuel injection device for a cylinder of a diesel engine according to claim 1, characterized in that it has a displacement device 30 acting on a timer 29 to change the starting operation time. 10. The cylinder of a diesel engine according to claim 9, characterized in that it has a displacement device 30 which calculates the starting operating time according to the instantaneous operating parameters and sends a corresponding signal S_D_1 to the timer 29. Fuel injection device.