JPS58135333A - Electronically controlled fuel injection pump - Google Patents

Abstract

PURPOSE:To obtain an optimum fuel injection rate and reduce the noise and vibration and also improve the exhaust gas property by a method wherein the shape of a spill part and the location of a spill ring which control the fuel injection quantity in a distributor type fuel injection pump are specially fixed. CONSTITUTION:A fuel injection pump 1 is arranged to reciprocate a plunger 15 through engagement between a roller 13 located at the end of a drive shaft 11 driven by the engine and a cam plate 14 to pressurize the fuel which is delivered through a delivery valve 51 into each fuel injection valve. At that time, the area of a spill port 50 and thus the fuel injection quantity is controlled in accordance with the location of a spill ring 21 which displaced by a linear solenoid 22. The spill port 50 is formed partially in the shape of a triangle having an acute angle at its top. Further, the pressure in a pumping chamber defined by the plunger 15 is detected by a pressure sensor 53, and on the basis of the output from the sensor 53 the solenoid 22 is controlled to obtain a target fuel injection rate pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronically controlled fuel injection pump, and in particular, it is an object of the present invention to provide an electronically controlled fuel injection pump that is most suitable for application to a distribution type injection pump for a diesel engine.

The fuel injection device in a diesel engine has the function of compressing intake air and injecting the fuel into a mist into the cylinder, which has become hot.It mainly consists of an injection pump and an injection nozzle, but also includes a fail tank and a fail field. Consists of a pump, fail filter, etc. There are two types of injection pumps: a format type and a distribution type. Representative types of the distribution type include the Lucas type and the Bosch type.

A distribution injection pump has the function of distributing fuel pressurized by one or a pair of plungers to each nozzle according to an injection order. For example, in the case of the Bosch type, fuel is filtered from the tank through the fuel water separator and fail tank, reaches the regulating valve by the eccentric feed pump, and after pressure adjustment is carried out, it is pumped into the pump housing. It is filled and then sent to the pump plunger. Bomb Blunger is
Reciprocating motion is provided by contact with a cam plate having a corrugated shape that rotates in contact with a roller driven by a drive shaft. laura cam
Fuel flows into the plunger when it reaches the concave position of the plate, and when the roller approaches the convex position of the cam plate, the distribution port of the plunger mates with one of the distribution passages of the delivery valve, and the plunger also moves into the cam plate. When the fuel reaches the top of the convex part of the plate, the pressure in the pressure chamber increases, and the fuel is injected from the injection nozzle into the engine combustion chamber via the delivery valve.

In this way, fuel injection is performed by the reciprocating movement of the plunger and the maintenance of the suction port, distribution port, and spill port, but with conventional injection pumps, the injection rate is constant, so the engine does not move rapidly. This results in high noise, high vibration, and worsening of emissions.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronically controlled fuel injection pump that eliminates the above-mentioned conventional drawbacks by optimally selecting the injection rate of fuel injected by the injection pump.

The present invention provides a fuel pump with a spill-over taper shape, a fuel pressure sensor that measures the fuel pressure in a high-pressure fuel chamber (pump plunger), and a target injection rate pattern based on the sensor output. This is to control the spilling.

The optimal fuel injection amount characteristics in a diesel engine are
- times of injection time, two peak characteristics as shown in FIG. 1 are required. However, in the conventional characteristic, the injection rate was constant as shown by the dotted line in the figure, which was not a desirable injection characteristic. In the present invention, the characteristics shown in FIG. 1 are used as a target injection rate pattern, and the spill ring is driven by electronic control to achieve the target injection rate pattern.

FIG. 2 is a configuration diagram showing an embodiment of the present invention, and FIG. 3 is a front view of a spill port section according to the present invention.

The fuel injection pump 1 includes a drive shaft 11 driven by an engine, a gear 12 and a roller 13 provided at the end of the drive shaft, a cam plate 14 loosely connected to the roller 13, and a spill port 50 inside. The position of the pump plunger 15 which is connected to the plate 14 and which supplies fuel to the injection nozzle 2 of the engine, the fuel pump 17 which supplies fuel to the injection nozzle 2 and the timer piston 16, and the timer piston 16 is electrically detected. Timer position sensor 18 that determines advance angle adjustment, timing control valve 19 that determines advance angle adjustment, and gear 1
an electromagnetic pickup sensor 20 as a rotational speed detector that outputs a pulse signal according to the rotational speed of 2, and a spill ring 2 that is driven by a linear adjustment to adjust the injection amount.
1. The spill ring 217! L-driving linear solenoid 22, coil 2 constituting the linear solenoid 22
3, a plunger 24 that drives the spill ring 21, a spill position sensor 25 that detects the amount of movement of the plunger 24, and an FCV 26 (excitation coil 27 and valve 28 that controls on/off of the amount of fuel to the pump plunger 15). It consists of a delivery valve 5 for preventing backflow or dripping of fuel from the pump plunger 15, a regulating valve 29, and a pressure sensor 53 for detecting the pressure in the high-pressure combustion chamber.

The cam plate 14 rotates and reciprocates together with the buttenger 15 in the pump. This reciprocating motion is caused by the roller 13, which is rotatable but fixed in the axial direction of the shaft.
This occurs when the cam plate 14 rides on the ground. Rotation of pump plunger 15 causes fuel to be dispensed from distribution port 52 . Regarding the adjustment of the injection amount, the maximum injection amount is determined by the effective stroke of the pump plunger 15. Excess fuel in the pump is returned to the pump 17 via the orifice 30. In addition, the linear solenoid 22 in the fuel pump 1 and the FCV 26
The control is performed by the control device 3, and for this purpose, output signals from various sensors are taken in. That is, the engine rotation speed signal SN from the electromagnetic pickup sensor 20,
These are the pump side information of the output signal Ss of the spill position sensor 25, the output signal of the pressure sensor 53, and the engine side information. Note that the timer position sensor 18 is used for timing control and is not related to the present invention, so a description thereof will be omitted. Engine side information includes an output signal Sa of an intake temperature sensor 5 provided in the intake manifold 4, an output signal Sp1 of an intake pressure sensor 6 also provided in the intake manifold 4, an output signal Sw of a water temperature sensor 7 that measures engine cooling water temperature, and an accelerator. There are output signals 5ACC of the accelerator sensor 9 for detecting the amount of pedal depression of 8, and these are shown in the figure to show each piece of information.

The outlet shape of the spill boat 50 is as shown in FIG. 3, and is triangular in contrast to the conventional round shape, with the top of the triangle having an acute angle. With such a shape, the characteristics shown in FIG. 1 can be obtained by moving the spill ring 21 from the fully closed state to the fully open state (that is, from the right side to the left side in FIG. 3).

FIG. 4 is a detailed block diagram of the control device 3.

A read-only memo that stores processing programs and monitor programs for executing various processes using the central processing unit (CPU) 31 as the core! J (ROM)
32, a random access memo IJ (RAM) 33 having a backup memory that temporarily stores calculation contents and output contents of each sensor, and continues to store calculation contents, setting values, etc. when the power is turned off; The second input/output circuits 34 and 35 connect to the CPU 3 via the pass line 36.
1, forming a so-called microcomputer. The output devices connected to and controlled by the CPU 31 are the linear solenoid 22 and the FCV 26, and the non-switching output device 26 is driven via each of the drive circuits 41 and 38. , the linear solenoid 22 is driven via a D/A converter 39, a servo amplifier 40, and further via a drive circuit 41. The input/output circuit 34 is for taking in the sensor output, and the output of each sensor (5, 6, 7, 9, 25, 53) (buffer 42
, 43, 44, 45, 46. The data is output to 36. Furthermore, a rotation speed detector 20 detects the rotation speed of the engine.
is provided, and the output signal is waveform-shaped by a waveform shaping circuit 54 and then sent to the CPU 31. A clock circuit 55 is provided to send clock pulses to the CPU 31, each input/output circuit 34, the A/D converter 48, and the D/A converter 39.

5(a) and 5(b) are spill ring control flowcharts by the control device 3, and FIGS.
The flows in Figure (b) are used in conjunction.

First, in step 501, the spill boat is initialized, ie, the spill boat is in a fully closed state as shown in FIG. In this state, in step 502, various information such as the rotational speed Ne, accelerator opening θ, engine water temperature Tw, etc. is taken in from the sensor, and based on these, the fuel charge Q is calculated in step 503. Furthermore, in step 504, each of the pressure Ps at the timing of fuel leakage from the spill boat, the pressure Pf at the fuel closing timing, and the timing To for complete fuel leakage?
, Ne, θ based on the two-dimensional map
Calculate while correcting by etc. During the series of processes described above, the injection amount increases with respect to the characteristic (2) in FIG. 1. Next, in step 505, based on each of Q + PS + Pf, the amount of movement t31.
Calculate tS2. Also, in step 506, tSl
The duty ratio DSI DS□ as the solenoid driving time corresponding to +tS2 is determined.

When the above calculations are completed, in step 507, check whether the flag FPo indicating the start of fuel pressurization is set (
In other words, whether the flag FPo is not established, it is determined in step 508 whether or not the relationship between the fuel pressure P at the time measured by the pressure sensor 53 and the fuel leakage timing pressure Ps is P>Ps. In other words, it is determined whether or not the peak point of characteristic (2) in FIG.
is set, and if P<Ps, initialization is performed again.

In step 509, the flag FPo is set again even if establishment of the flag is recognized in step 507.

Next, in step 510, it is determined based on a flag FP whether pressurization for characteristic (2) in FIG. 1 has been started. If flag FP is not equal to 1, step 51
At step 1, it is determined whether or not the peak point of characteristic (1) is reached by determining whether Pl-Ps is reached, and at step 512, the linear solenoid 22 is moved by a moving amount ts as shown in FIG.
1 and duty D, 1. As a result, the characteristic (2) shown in FIG. 1 begins to decrease. After passing through the valleys of characteristics (2) and (2), the fuel must be pressurized again to obtain characteristic (2). The process for this is shown in Figure 5(b).
It is.

In step 512, it is determined based on the flag FP whether or not the second fuel pressurization is being performed.

If the flag FP is set, the current time T1 is read in step 513 and preparations are made for the processing described later. If the flag FP1 is not set, the current fuel pressure P and fuel are set in step 514. The relationship with the closing timing Pf (P<Pf) is determined, and it is determined whether or not it is on the upward curve of characteristic (2). If it is determined that there is no operating point on the rising curve, the processing up to the peak of characteristic (2) is checked again. Since it is determined that there is a reason to process between the starting point and the top of the characteristic ■, the current time T is determined in step 513.
1 and at the same time, in step 515, the fuel leak flag FP is read.
It is determined whether or not there is 2, and it is determined whether or not the state is such that a future process should be performed from the present time prior to the second pressurization. F
If P2 does not exist, step 516 sets the linear solenoid 22 to duty DS2 and movement amount ts.
2, the fuel is closed, and an injection characteristic that follows the rising curve of characteristic (2) is obtained. Further, in step 517, it is determined whether the sum of the current time T1 and the complete fuel leakage timing To is less than or equal to the set time, and when it is (set time': 2-Tt + To), the duty DS is determined in step 518. At the time of □=0, the spill ring 21 is returned to the state shown in Fig. 8, and the characteristic ■
get. In step 520, the fuel leak progresses and the current fuel pressure reaches the preset fuel injection end fuel pressure Pe, which is determined in step 520, and in step 521, the flags FPo and FPI are reached and set to FPo=FP,=O.
Prepare for the next process.

As described above, according to the present invention, the optimum injection rate can be obtained by devising the hole shape of the spill port and controlling the position of the spill ring so as to obtain injection with optimum characteristics, thereby reducing noise. , low vibration, and low exhaust gas emissions can be achieved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, FIG. 3 is a front view of the spill port section according to the present invention, and FIG. 4 is a diagram of the control device 3. detailed block diagram,
FIG. 5 is a processing flowchart of the present invention, and FIGS. 6, 7, and 8 are operation modes of the linear solenoid accompanying the control of the present invention. 1...Fuel injection pump, 3...Control device, 9...
Accelerator sensor, 11... Drive shaft, 12...
... Gear, 13 ... Mouth, 14 ... Cam plate, 15 ... Pump plunger, 16 ... Timer piston, 18 ... Fuel pump, 19 ... Timing control valve, 20 ...Electromagnetic pink up sensor, 21°/°spill ring, 22...linear solenoid, 24...plunger, 25...spill position sensor, 26...FCV131...central processing unit (CPU
), 32...ROM, 33...RAM. 34.35... Input/output circuit, 36... Pass line,
38.41... Drive circuit, 39... D/A converter,
40...Servo amplifier, 45,54.56...°buffer, 47...Multiple break, 48...A/
D converter, 50... spill boat, 51... delivery valve, 52... distribution port, 53... pressure sensor. Agent Tatsuyuki Unuma (2 idiots) Figure 3 41, 4 Hi Japanese Patent Publication No. 58-135333 (6) Figure 5 (a) Kai Tomoe 501 Ne, e3. Tw”fcpyQQ Performance 1 of 502Q
503 Figure 5 (b) Figure 6 Figure 7 σ Mitsu 8 187-

Claims (1)

[Claims] (1) Fuel pressurized by a plunger driven by an internal combustion engine is sequentially delivered to each fuel injection nozzle provided in the internal combustion engine in a predetermined manner by movement of a spill ring that is driven by an electromagnetic mechanism and fitted externally to the plunger. In an electronically controlled fuel injection pump that distributes the injection amount, the plunger is connected to a tapered spill boat whose opening area gradually increases toward the cam plate and whose opening surface is fully closed and fully opened by the movement of the spill ring. and a pressure sensor for measuring the fuel pressure in the plunger is provided in the pump body, and the electronically controlled fuel injection pump controls the movement of the spill ring so that the optimum injection rate is achieved based on the output signal of the pressure sensor.