JPH0458044A - Fuel injection device - Google Patents

Abstract

PURPOSE:To reduce noise from an engine, to prevent excessive fuel injection, to improve exhaust gas and to miniaturize a fuel injection device by providing such an arrangement that a controller controls the injection timing and fuel feed rate of a fuel injection valve, independently from each other. CONSTITUTION:A controller 17 controls the injection timing and fuel feed rate of a fuel injection valve 4, independently from each other. With this arrangement, in a fuel injection device, a first solenoid valve 16 controlled by the controller 17 adjusts the fuel feed rate, and a hydraulic timer 46 controlled by first and second solenoid valves 42, 43 controls the injection timing, and accordingly, the fuel feed rate, the fuel injection timing and the fuel injection volume can be freely set to optimum values even in an engine rotational speed range and in a low load range. Accordingly, it is possible to reduce noise during idle operation and to enhance the output power during low load operation. Meanwhile, during a high rotational speed but low load operation, the injection is made at a low injection rate so as to prevent excessive fuel injection in order to enhance the durability of the fuel injection system as well the durability of the engine, thereby it is possible to reduce vibration and noise caused by rotation of the engine.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a device for injecting fuel pressurized by a fuel injection pump of an internal combustion engine into a combustion chamber, and particularly to a device for injecting fuel pressurized by a distribution type injection pump into a combustion chamber. Regarding an injection device.

(Prior Art) Internal combustion engines, particularly diesel engines, inject fuel into high-temperature, high-pressure air in a combustion chamber to perform compression ignition to obtain a predetermined output.

In this way, in a diesel engine, the fuel is pressurized by the fuel injection pump, which is driven by part of the engine's driving force, and this fuel is guided through the injection pipe to the fuel injection valve. Fuel is sprayed into the combustion chamber.

The fuel injection pumps used here include a row type fuel injection pump and a distribution type fuel injection pump.

A row-type fuel injection pump is equipped with plungers equal to the number of cylinders in an internal combustion engine, and each plunger is driven by an opposing cam to pressurize fuel. On the other hand, a distribution type fuel injection pump pressurizes fuel by reciprocating a single plunger and distributes fuel to multiple cylinders by rotating the plunger.

As described above, the distribution type fuel injection pump has a relatively smaller number of parts than the single-row type fuel injection pump, and is easily miniaturized, so it is widely used.

By the way, as an example of this distribution type fuel injection pump is shown in FIG. 8, rotational force is transmitted from the engine side to a plunger 2 that slides and rotates within a pump sleeve 1, and a face cam 3 that is integrally connected. The plunger 2 is configured to slide and operate the pump when the roller 4 comes into rolling contact with the pump.

Here, the pivot member 5 of the roller 4 uses a hydraulic timer to advance or retard the lift operation timing of the face cam.
This mechanism adjusts the injection timing of the pump. On the other hand, a spill ring 6 operated by an accelerator link system equipped with a governor (not shown) is inserted into the plunger 2, and the fuel injection amount is adjusted according to the position at which this ring opens the spill boat 7. ing.

(Problem to be solved by the invention) In this way, in the distribution type fuel injection pump used in the conventional fuel injection device, the hydraulic timer for adjusting the oil feed rate, injection timing, and fuel injection amount can be adjusted to increase or decrease depending on the hydraulic pressure value. The spill ring 6 is directly operated by an accelerator link system equipped with a governor (not shown).

However, this type of conventional device has a limited response, and furthermore, the conventional hydraulic timer and spill ring have a relatively narrow control range and a low degree of freedom in control, causing problems in controllability.

An object of the present invention is to provide a fuel injection device that can improve responsiveness and controllability.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has one end coupled to a rotating shaft driven by an internal combustion engine so as to rotate integrally therewith, and a roller attached to a roller on the base side of an injection pump. a plunger integrally connected with a contacting face cam; a hydraulic timer that rotates a pivot member of the roller in the rotational direction of the face cam to advance or retard the lift operation timing of the face cam; and the plunger. A plunger hole is formed into which the other end is slidably and rotatably inserted, and a plurality of distribution passages are formed to guide fuel pressurized in a pressure feeding chamber in the plunger hole to each fuel injection valve of a plurality of cylinders. a normally open solenoid valve for timely closing the gap between the pressure feeding chamber and the spill boat; a timer solenoid valve for supplying and discharging oil for advancing or retarding the hydraulic timer; and the internal combustion engine. a controller that receives engine rotation speed information, load information, and crank angle information from a rotation speed sensor, a load sensor, and a crank angle sensor and issues an opening/closing output to the normally open solenoid valve and the timer solenoid valve; The present invention is characterized in that the injection timing and oil feed rate of the fuel injection valve are controlled independently of each other.

(Function) The normally open solenoid valve can close the space between the pressure feeding chamber and the spill boat in a timely manner, and the timer solenoid valve can supply and discharge pressure oil to advance or retard the hydraulic timer, and these solenoid valves can be controlled by the controller. This controller can independently adjust the oil feed rate and the injection timing.

(Embodiment) The fuel injection device shown in FIG. 1 is attached to a fuel supply system 10 of a multi-cylinder diesel engine.

A fuel supply system 10 of this diesel engine supplies fuel from a fuel tank 11 to a distribution fuel injection pump (hereinafter simply referred to as an injection pump) 12 via a filter (not shown).
It is configured to supply fuel pressurized by the pump to a fuel injection valve 14 via an injection pipe 13.

Here, the fuel injection valves I4 are provided as many as the number of cylinders in the engine, and each is connected to the injection pump 12 via an injection pipe 13. Note that the injection pipe 13 and the fuel injection valve 1 are shown here.
Only one 4 was shown.

Here, the reference numeral 15 indicates the 1 to lane road.

The fuel injection device is connected to a controller 17 that drives a distributed fuel injection pump 12, a normally open first solenoid valve 16 of the pump, and second and third solenoid valves 42 and 43 as timer solenoid valves. It is composed of a load sensor 18, a crank angle sensor 19, a rotation sensor 41, and an advance angle sensor 44.

A needle valve (not shown) is disposed in the fuel injection valve I4, and the needle valve receives fuel from the injection pump 12 that is pumped through the injection pipe 13, and changes the injection pressure Pf in the injection pipe.
A needle valve (not shown) is lifted R in response to a change in the injection pressure Pf, and fuel is injected in a predetermined injection amount pattern as shown in FIG. 2, for example.

The injection pump 12 includes a rotating shaft 21 that is pivotally supported by a casing 20 as a base, a feed pump 22 attached to the rotating shaft 21, and a pump sleeve 23 that is a part of the base.
A plunger 26 is connected to the rotating shaft 21 via a joint 24 and is slidably and rotatably fitted into the plunger hole 25 of the pump sleeve 23, and a rotating frame 45 that pivotally supports four rollers 27. A hydraulic timer 46 rotates in the rotation direction R of the plunger 26.

A face cam 28 that rolls into contact with a roller 27 supported on the casing 20 side, a pressure feeding chamber 29 that forms a part of the plunger hole 25 within the pump sleeve 23, and a drain passage 15.
A normally open first solenoid valve 16 is provided to timely close the gap between the spill boat 30 and the spill boat 30 communicating with the spill boat 30 .

Here, the rotating frame 45 pivotally supports four rollers 27 arranged in an annular shape, and this rotating frame supports a part of the locking piece 45.
1 to the hydraulic timer 46.

As shown in FIG. 2, the hydraulic timer 46 is slidably fitted into a hydraulic chamber 48 formed in a part of the casing 20, and is biased in the retarding direction a by a return spring 49. It is composed of a piston 47. This hydraulic chamber 48 is configured to be supplied with pressure oil from the feed pump 22 via a second electromagnetic valve 42 and to return the pressure oil to the drain passage 15 via a third electromagnetic valve 43 on the branch pipe 30. ing. This oil pressure timer 46 is operated as shown in FIG.
It is configured to rotate in the advance angle direction as O increases, and to switch and move each roller 27 of the rotation frame 45 from the retard minimum position (mini) to the advance angle maximum position (max). There is.

The second and third electromagnetic valves 42 and 43 are duty valves, and are configured to increase the valve rate as the duty ratio Du increases.

The face cam 28 is formed with four lift parts r, and when these parts face the four rollers 27, the face cam 28 and the plunger 26 are lifted in the pump operation direction P, and the plunger 26 is lifted as shown in FIG. Amount R
It is configured such that p changes. Note that the joint 24 is configured to connect the rotating shaft 21 and one end of the plunger 26 so that they can be relatively moved toward and away from each other, and so that they can be integrally moved.

The plunger 26 is provided with a central passage 32 communicating with the pumping chamber 29 at the other end, and is configured such that the distribution groove 33 at one end faces the four distribution passages 34 of the pump sleeve 23 in sequence, and is always connected to the pumping chamber 29. The opposing suction grooves 35 are configured to face the suction passage 36 of the pump sleeve 23 .

Here, the suction passage 36 is connected to the foot pump 22 via a cam chamber 37.

In addition, the code|symbol 38 shows the overflow orifice provided in the train path 15, the code|symbol 39 shows the return spring of the plunger 26, and the code|symbol 40 shows a delivery valve.

The first solenoid valve 16 is normally open, and when it receives a closing output, the first solenoid valve 16
Switch to the closed position as shown in the figure.

The controller 17 includes a control circuit 171, a memory circuit 172,
It is composed of an input/output circuit 173, cantering circuits 174, 175, a power supply circuit (not shown), and the like.

The input/output circuit 173 in the controller 17 includes the above-mentioned load sensor 18, crank angle sensor 19, and rotational speed sensor 41 that outputs engine rotational speed information. It is configured to receive each detection signal from an advance angle sensor 44 or the like that detects the injection timing T from the hydraulic timer 46 side. The memory circuit 172 is shown in FIG.
), the injection control program shown in (b), the calculation map of the du ratio of the second and third solenoid valves 42 and 43 for adjusting the injection timing T of the hydraulic timer as shown in FIG. (a)
, (b), a calculation map for the oil feed rate (Δq/Δt), and a calculation map for the injection timing T are respectively set and stored.

Here, the calculation map for the oil feed rate (Δq/Δ) shown in FIG. 6(a) is set so as to obtain the following characteristics.

Here, a low oil delivery rate (∆
q/Δt) to prevent excessive injection, improve durability, reduce particulates, and Hc, and achieve a high oil delivery rate at low and medium rotations and medium-high loads, thereby increasing output through high-pressure injection. is possible. On the other hand, in the calculation map of the injection timing T shown in FIG. 6(b), the following characteristics are set. Here, the engine is retarded at low rotation speeds and low loads to reduce idle noise, and is also delayed at high speeds and high loads to improve engine durability and reduce exhaust gas and He.

The control circuit 171 calculates the control amount according to the injection control program in the memory circuit 172, and controls the drive circuit 1 of the first solenoid valve 16.
74, a drive circuit 175 for the second and third electromagnetic valves 42 and 43, and is configured to perform pressure regulation control of the injection pressure Pf.

Here, the operation of the fuel injection system will be explained along with the injection control program L shown in FIGS. 7(a) and 7(b).

When a main switch (not shown) of the engine is turned on, the controller 17 starts operating the main routine.

First, set the current engine speed N, load, and crank angle θ
, injection timing T, etc., and store them in a predetermined area.

Then, the target injection timing T and oil feeding rate (Δq/Δt) according to the engine speed N and load are the injection timing T and oil feeding rate (Δq/Δt) shown in FIGS. 6(a) and (b). ) is calculated based on the calculation map and stored in a predetermined area.

In step a3, the difference ΔT (=T-Tn) between the current injection timing Tn and the target injection timing T is calculated, and the ΔDu ratio corresponding to the difference ΔT is calculated from the Du ratio calculation map (see FIG. 4). Then, the current duty ratio DU is corrected and updated by adding or subtracting the ΔDu ratio.

In step a4, the second and third electromagnetic valves 42 and 43 are driven with the updated Du ratio, and the process returns to step a1. in this case,
If it is desired to further advance the current injection timing Tn by the difference ΔT, the correction amount ΔDu ratio becomes a positive value, the duty ratio of the second solenoid valve 42 is updated, and the second solenoid valve 42 is driven with the same output. On the other hand, if it is desired to retard the current injection timing Tn by the difference ΔT, the correction amount ΔDu ratio becomes a negative value, and the duty ratio of the third solenoid valve 43 is updated with the same output.

On the other hand, a control routine (not shown) sequentially counts the crank angle signal θ by interrupt processing.

Furthermore, step b1 is reached due to the interruption of the reference signal θ0 for each cylinder, where the solenoid valve on time t1 corresponding to the current injection timing Tn is calculated and set in a counter, and further,
The solenoid valve off time t2 at which the injection time t that can secure the injection amount q according to the load information is obtained is calculated, set in a counter, and returned.

Through this process, fuel is supplied from the injection pump to the fuel injection valve 14 for a predetermined time period (tl to t2), and the valve opening pressure p
When the temperature exceeds a, the injection valve lifts, fuel injection is performed, and characteristics along the maps shown in FIGS. 6(a) and 6(b) are obtained.

In this way, in this fuel injection device, the first solenoid valve 16 operated by the controller adjusts the oil feeding rate (Δq/Δt).
The oil feed rate at the tb position is smaller than the ta position in Fig. 5), and the injection timing T is the second and third solenoid valve 42.
(the plunger lift and its speed Vρ in FIG. 5 are adjusted from the retard side shown by the solid line to the advance side shown by the two-dot chain line), which is operated by the hydraulic timer 46, which is operated by the oil feeding rate (Δq
/Δt), injection timing T, and injection amount can be freely set to the optimum conditions in the engine rotation range and load range. Therefore, it is possible to reduce noise during idling and improve output at low speeds and high loads. On the other hand, at high rotations and low loads, injection is performed at a low injection rate (Δq/Δt) to prevent excessive injection, improve the durability of the injection system and engine, and reduce vibration and noise caused by engine rotation. I can do it.

Furthermore, this fuel injection device can eliminate a spill ring operated by an accelerator link system equipped with a governor, making it easy to downsize the device.

Furthermore, the oil feed rate (Δq/Δ
t), the injection timing T and the injection amount can be adjusted appropriately, and the responsiveness during these controls is improved.

(Effects of the Invention) As described above, in the present invention, the normally open solenoid valve operated by the controller can adjust the oil feed rate, and the injection timing can be adjusted by the hydraulic timer operated by the timer solenoid valve. Therefore, oil feed rate and injection timing.

The injection amount can be freely set to the optimum state within the engine rotation range and load range, reducing engine noise and preventing excessive injection.
It is easy to improve exhaust gas and downsize the equipment.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a fuel injection system as an embodiment of the present invention, Fig. 2 is a side sectional view of the hydraulic timer shown in Fig. 1, Fig. 3 is a diagram of the operating characteristics of the same hydraulic timer, and Fig. 4 is a diagram showing the operating characteristics of the same hydraulic timer. The figure is a characteristic diagram of a ΔDu calculation map built into the controller of the same device, FIG. 5 is an operation characteristic diagram of each part during control performed by the same device, and FIG. 6 (a). (b) is the injection rate (
7(a) and 7(b) are flowcharts of the control program for the same device, and FIG. 8 is a sectional view of the main parts of a conventional injection pump. be. 1...Diesel engine, 12...Injection pump,
14...Fuel injection valve, 16,42.43...Solenoid valve, 17...Controller, 18...Load sensor, 1
9... Crank angle sensor, 20... Casing, 2
1...Rotating shaft, 23...Pump sleeve, 25...
・Plunger hole, 26... Plunger, 27... Roller, 28... Face cam, 29... Pressure feeding chamber,
30... Spill port, 34... Distribution passage, 41...
... Rotation sensor, 44... Advance angle sensor, 46... Oil pressure timer. Chibareda 1←H Yume da mouth Kutsutsukuji [θ] 1 6th figure/, d) 弗d圀

Claims (1)

[Claims] A plunger whose one end is integrally connected to a rotating shaft driven by an internal combustion engine so as to rotate integrally with a face cam that contacts a roller on the base side of the injection pump, and a pivot member of the roller is connected to the face. A hydraulic timer is formed that rotates in the rotational direction of the cam to advance or retard the lift operation timing of the face cam, and a plunger hole into which the other end of the plunger is slidably and rotatably inserted. A normally open pump sleeve formed with a plurality of distribution passages that guide fuel pressurized in the pressure-feeding chamber in the plunger hole to each fuel injection valve of the plurality of cylinders, and a normally open space that closes the gap between the pressure-feeding chamber and the spill port in a timely manner. a solenoid valve, a timer solenoid valve for supplying and discharging oil for advancing or retarding the hydraulic timer, and a rotation speed sensor, a load sensor, and a timer solenoid valve for supplying and discharging oil to advance or retard the hydraulic timer; The controller includes a controller that outputs an opening/closing output to the normally open solenoid valve and the timer solenoid valve in response to the crank angle sensor, and the controller controls the injection timing and oil feed rate of the fuel injection valve independently of each other. A fuel injector configured with.