JPH0730724B2 - Fuel injection timing controller for engine with pressure wave supercharger - Google Patents

Description

The present invention relates to a fuel injection timing control device for an engine, and more particularly to a supercharging effect by compressing intake air using a pressure wave generated based on the pressure of exhaust gas. The present invention relates to a fuel injection timing control device in a diesel engine including a pressure wave supercharger and a fuel injection pump.

(Prior Art) As a kind of supercharger provided for engines for automobiles, especially diesel engines, it is generated on the basis of the pressure of exhaust gas as shown in, for example, JP-A-60-150428. There is a so-called pressure wave supercharger designed to obtain a supercharging effect by compressing intake air using a pressure wave. This pressure wave supercharger A, as shown in FIG.
A rotor C having a cylindrical casing B and a plurality of blades C ₁ ... C ₁ rotatably held in the casing B.
Is composed of a, the casing intake air introducing passage D ₁ derived from an air cleaner (not shown) in the intake inlet B ₁ formed on one end face of the B is also air discharge port B ₂ intake valve is The intake and discharge passages D ₂ leading to the combustion chamber via E are connected to each other, and the exhaust introduction port B ₁ ′ formed on the other end surface of the casing B is guided from the combustion chamber via an exhaust valve F. The exhaust gas introduction passage G ₁ is connected to the exhaust gas discharge passage B ₂ ′, and the exhaust gas discharge passage B ₂ ′ is connected to an exhaust gas discharge passage G ₂ that communicates with the atmosphere via a silencer or the like. Then, the rotor C blades C ₁ ... C ₁ and the casing B (or not shown, a sleeve covering the rotatably held in each blade C ₁ ... C ₁ tip in the casing B) and a plurality of H-shaped passages H ... H are formed, and the rotor C is rotationally driven at a predetermined speed in synchronization with the rotation of the crankshaft I, so that the respective groove-shaped passages H ... H are introduced at predetermined times. Mouth and discharge port B ₁ , B ₂ , B ₁ ′,
B ₂ ′ are respectively opened to generate a flow of intake air and an exhaust gas in the passages H ... H.

Here, the operation of the pressure wave feeder A will be described based on FIG. 7 in which the rotor C is expanded for convenience. That is, assuming that the groove-shaped passages H ... H move downward (in the drawing) as the rotor C rotates, the right end of the uppermost groove-shaped passage H filled with intake air is the exhaust inlet B ₁ ′. At the time of opening the valve, the high-pressure exhaust gas flows into the hatched portion (a) of the passage H and collides with the intake air in the atmospheric pressure state, so that a pressure wave of the intake air, that is, a compression wave is generated. Then, this compression wave propagates to the left and causes a flow of intake air in the passage portion (b) shown by the dotted line in the figure, but in that case, as the groove passage H moves downward, the exhaust gas is exhausted. The gas inflow increases and the passage portion in which the intake flow occurs is gradually expanded. Further, the passage H moves downward, and the left end thereof is opened to the intake / exhaust port B ₂ formed slightly below the position opposed to the exhaust introduction port B ₁ ′, whereby intake air is taken. It is discharged to the combustion chamber after being discharged to the intake / discharge passage D ₂ while being compressed by the action of the compression wave. As described above, while the groove-like passage H is open to both the exhaust introduction port B ₁ ′ and the intake / exhaust port B ₂ , the above operation is continuously performed. If the groove-shaped passage H moves downward from such a state and only the right end of the groove-shaped passage H is closed by the end surface of the casing B, an exhaust stationary portion is formed in the portion indicated by a dotted line in the passage H. The intake air is still being discharged due to the expansion of the exhaust gas, and the groove-like passage H moves further downward so that the passage H
When both ends of are closed, in addition to the exhaust stationary part shown by the dotted line, an intake stationary part is generated on the left side thereof.

On the other hand, the groove-like passage H is that only the right end is an exhaust discharge opening B ₂ moves further down with the rotation of the rotor C 'when it is opened, the discharge port B _2' is vented to atmosphere Due to this, the exhaust gas expands and flows out into the exhaust gas discharge passage G ₂ in the passage portion (c) shown by the diagonal lines in the figure, but at this time, a negative pressure state is generated as the exhaust gas expands. Pressure wave, that is, an expansion wave is generated, and this expansion wave propagates to the left to generate a flow of intake air in the passage portion (d) shown by the dotted line in the figure. The left end of the groove-like passage H is at the intake inlet B ₁
The opening of the intake port causes the intake air to be sucked from the intake introduction passage D ₁ by the expansion wave of the negative pressure as shown by the reference numeral (e) in the figure, and the exhaust gas is pushed out accordingly, and the groove shape is formed. As the passage H moves downward, the amount of inflow of intake air gradually increases, and the amount of exhaust gas is gradually decreased so that the entire amount is finally discharged. When only the left end of the groove-shaped passage H is closed, an intake stationary portion shown by a dotted line is generated in a part of the passage H, and when both ends of the passage H are closed, intake air is not drawn. All become stationary.

The pressure wave supercharger A, which performs supercharging of intake air and additionally scavenging of exhaust gas based on the above operation, has a pressure or temperature of the exhaust gas introduced from the exhaust gas introduction passage G ₁ When the pressure wave is within a predetermined value or within a predetermined range, a desired pressure wave is generated in the groove passages H ... H, and a good supercharging capacity and the like can be obtained by this pressure wave. Compared with a turbocharger of a type whose supercharging capacity mainly depends on the flow rate of exhaust gas, it has an advantage that a supercharging effect in a low rotation region and the like can be excellently obtained.

(Problems to be Solved by the Invention) By the way, the pressure wave supercharger described above has a desired pressure (compression) in a high rotation and high load region where the effect of improving the engine output is required, that is, in an operating region where the exhaust gas temperature becomes high. Waves) are generated and the maximum supercharging capacity is obtained, so that the intake and exhaust inlets and outlets are arranged, or the length of the groove-like passage and the passage cross-sectional area are set. In the middle load area, etc.
Due to the relatively low exhaust gas temperature, the desired pressure wave does not occur and sufficient supercharging capacity cannot be obtained.Therefore, the acceleration performance or engine response in such an area deteriorates, and It becomes difficult to secure driving performance. Further, in the medium-rotation medium-load region, etc., not only the desired pressure wave, that is, the compression wave for supercharging the intake air cannot be obtained as described above, but also the exhaust gas indicated by the hatched portion (c) in FIG. At the time of discharge of the exhaust gas, a sufficient expansion wave is not generated for favorably performing the discharge, so that the exhaust gas is reliably discharged between the time when the groove-shaped passage H is opened to the exhaust discharge port B ₂ ′ and the time when it is closed. Therefore, a large amount of the exhaust gas remains in the passage H due to the closed gas. Then, the exhaust gas in the residual has been multiplexed, when the groove-like passage H is opened to intake gas outlet port B _2, be supplied (refluxed) into the combustion chamber is discharged from the discharge port B ₂ with the intake Therefore, there arises a problem that the exhaust gas recirculation amount in the medium-rotation / medium-load region and the like becomes unnecessarily large and the combustion state and the like deteriorate.

The present invention addresses the above problems in the case where an engine, particularly a diesel engine, is provided with a pressure wave supercharger, and the exhaust gas temperature rises as the fuel injection timing retards. Paying attention to the characteristics possessed by, by adding a predetermined configuration or means to the fuel injection pump for controlling the injection timing, while securing a desired supercharging effect and output performance in a high rotation and high load region, In particular, in the mid-range / medium-load range, where the exhaust gas temperature is relatively low, it is difficult to obtain a sufficient supercharging effect. To prevent undesired increase in the amount of fuel and deterioration of flammability due to this
The purpose is to ensure good driving performance over a wide driving range.

(Means for Solving Problems) The present invention is configured as described below to achieve the above object.

That is, the pressure wave supercharging and the fuel injection pump, which are configured to obtain the supercharging effect by compressing the intake air using the pressure wave generated based on the pressure of the exhaust gas, are provided, and based on the operating region. In an engine configured to control the fuel injection timing by the fuel injection pump to a predetermined value, the fuel injection timing is set when the operating region is in a predetermined region excluding a low rotation low load region and a high rotation high load region. Is provided with a control means for controlling the delay angle with respect to the predetermined value.

(Operation) According to the above configuration, since the exhaust gas temperature does not reach the predetermined temperature, it is difficult to obtain a sufficient supercharging effect by the pressure wave supercharger. In the operating region of, the so-called afterburn occurs due to the fuel injection timing being retarded from the normal injection timing in that region, and the exhaust gas temperature is raised by this afterburn, so the pressure wave supercharge The desired supercharging effect by the machine is secured, and the engine response and the like are effectively improved. Moreover, in such an area, conventionally,
Due to the exhaust gas temperature not reaching the predetermined temperature, the scavenging efficiency of the exhaust gas by the supercharger was impaired, and the recirculation amount of the exhaust gas was unnecessarily increased accordingly. Such a problem can be effectively eliminated by raising the exhaust gas temperature as described above.

In the high rotation and high load region and the low rotation and low load region, since the retard control of the fuel injection timing is not performed, the exhaust gas temperature excessively rises in the high rotation and high load region and various exhaust system The desired supercharging effect and engine output in this region can be obtained without causing the above-mentioned adverse effects, and the deterioration of the combustion state and the occurrence of misfire in the low rotation and low load region can be prevented in advance.

(Example) Hereinafter, the Example of this invention is described based on drawing.

First, a pressure wave supercharger, which is one of the components of the present invention, will be described. As shown in FIG. 1, the supercharger 1 includes a cylindrical casing 2 and a casing 2 in which the supercharger 1 is rotatable. The rotor 3 is fitted and held. The rotor 3 has a plurality of groove-shaped passages 4 ... 4 formed by an inner peripheral wall 3a, an outer peripheral wall 3a, and a large number of blades 3c ... 3c partitioning the peripheral walls 3a, 3b at equal intervals. In this configuration, the rotor 3 is rotationally driven by transmitting it to the rotor shaft 5 via a rotary belt of a crankshaft, etc., but in this case, the rotor 3 is rotationally driven at a speed twice as fast as the crankshaft.

Further, the pressure wave supercharger 1 is provided with an intake air inlet 7 for introducing intake air introduced from an air cleaner (not shown) into the rotor 3 (groove 4) through the intake air introduction passage 6.
And the intake air in the rotor 3 to the intake air discharge passage 8 (this passage 8
A downstream side of the combustion chamber is provided with a shutter valve 9 for bypassing the supercharger 1 at the time of starting, and a one-way valve 10a provided in the bypass passage 10 and opened by negative suction pressure). Intake port 11 for supplying the exhaust gas from the combustion chamber to the rotor 3 through the exhaust introduction passage 12 and exhaust gas for discharging the exhaust gas in the rotor 3 Exhaust gas discharge ports 15 for discharging to the atmosphere via the air passage 14 are provided at predetermined set positions, each having a predetermined opening area. In addition, the lubricating oil is supplied from the oil inflow hole 16 to the periphery of the bearing portion of the rotor shaft 5, and the oil that lubricates the bearing portions is discharged through the oil outflow hole 17. .

Next, the fuel injection pump, which is the main component of the present invention, will be described based on FIG.

As shown in the figure, a fuel injection pump 20 includes a drive shaft 21 driven to rotate by a crank shaft (not shown) via a belt and the like, and a drive shaft 21 driven by the drive shaft 21 to draw fuel from a fuel tank and to inject the fuel. Vane-type feed pump 22 that discharges to pump chamber 20a of 20 (the pump 22 is shown expanded at 90 ° at the left end in the drawing) and drive shaft 21 is allowed to move only in the axial direction. It has a cam disk 24 connected via a joint 23 and a plunger 26 fixed to the cam disk 24 and having a tip end reciprocally held in a cylinder 25.

The feed pump 22 sucks the fuel introduced from the fuel tank to the fuel suction passage 27 through the suction port 22a, and at the same time, the rotational speed of the drive shaft 21 (engine speed).
Is configured to discharge the fuel having a discharge pressure or discharge amount corresponding to the above into the pump chamber 20a of the fuel injection pump 20 through the discharge port 22b. The fuel is allowed to flow into the return passage 29 through the regulating valve 28, and the fuel suction passage 27 is again provided.
It is designed to be supplied to.

Further, the cam disk 24 has its cam surface contacted with the circumferential surface of a roller 31 supported by a roller holder 30 having the same number of cam ridges as the number of cylinders and being rotatable by a predetermined angle. At the same time, by rotating the disk 24 while rolling the roller 31 at a predetermined position, the plunger 26 reciprocates at a predetermined cycle. And
The plunger 26 has the same number of slits 26a ... 26a as the number of cylinders at the tip thereof, and when the plunger 26 moves backward (moves leftward in the drawing), the pump chamber 20a passes through the slit 26a. The fuel flows into the cylinder 25, and the injected fuel is compressed by the forward movement of the plunger 26 and flows to the periphery of the delivery valve 32 via the internal passage 26b formed in the plunger 26. Further, the valve 32 is opened to be supplied into the combustion chamber through an injection pipe and a fuel injection nozzle (not shown).

In this case, if the engine speed, that is, the rotation speed of the drive shaft 21 is increased, the discharge capacity of the feed pump 22 is increased, and the fuel pressure in the pump chamber 20a of the injection pump 20 is increased. , The pump room 2
A piston 34 formed below 0a and held reciprocally in a chamber 33 communicating with the chamber 20a (in the drawing, the chamber 33 and the piston 34 are expanded 90 degrees for convenience.
Therefore, in reality, the piston 34 moves back and forth in the chamber 33 in the direction perpendicular to the driver shaft 21), but moves backwards against the spring force of the spring 35, so that the roll holder 30 moves to the pin 36. Is rotated in a predetermined direction via. Then, the relative positional relationship between the roller 31 and the cam disk 24 is shifted to a predetermined state as the roller holder 30 is rotated, so that the reciprocating timing of the plunger 26, that is, the fuel injection timing is advanced. It is said that. On the contrary, when the engine speed decreases, the fuel pressure in the pump chamber 20a also decreases and the piston 34
Is advanced, the fuel injection timing is retarded.

On the other hand, on the upper portion of the fuel injection pump 20, a lever shaft 37 interlocked with an accelerator pedal is fixed at the upper end and a lever shaft 37 having an eccentric shaft 37b at the lower end is rotatably attached, and the pump is also provided. An upper end of the chamber 20a is connected to the eccentric shaft 37b via a tension coil spring 38 at a predetermined portion of the chamber 20a, and is swung via a support shaft 39 in accordance with a depression operation of an accelerator pedal, that is, a rotation of the lever shaft 37. A control lever 40 is provided. The control lever 40 is composed of a tension lever 40a and a start lever 40b, and when the engine is started, the start lever 4c is acted upon by the spring force of the start spring 40c.
0b is in a state of being separated from the tension lever 40a as shown in the figure, but after the start is completed, the start lever 40a
The upper end of b contacts the tension lever 40a and both levers 40a
The a and 40b are configured to swing integrally. The lower end of the control lever 40 is connected to a cylindrical member 41 that is fitted in the plunger 26 and is movable in the axial direction, and the cylindrical member 41 moves as the lever 40 swings. Is moved, the effective stroke of the plunger 26, that is, the fuel injection amount is changed.

However, in the fuel injection pump 20, the guide shaft 42 protruding into the pump chamber 20a and the tip end fitted and held by the shaft 42 are the control lever 40 (start lever 40b).
And a sleeve 43 that abuts on one side of the sleeve 43. The sleeve 43 is configured to move back and forth in accordance with the swing of the control lever 40, that is, the change in the depression amount of the accelerator pedal. In this case, the rotation of the drive shaft 21 is transmitted to the flyweight holder 46 'via the first and second gears 44 and 45, but the centrifugal force generated at this time causes the rotation to the outside. Fly weights opened 46,4
6 urges or moves the sleeve 43 forward (to the right in the drawing) to balance the accelerator pedal depression amount, that is, the engine load with the rotation speed of the drive shaft 21, that is, the engine rotation speed. It is designed to be kept at. Further, the guide shaft 42 is formed with an internal passage 42a, one end of which is opened in the peripheral surface of the tip end thereof, and the other end of which is communicated with the return passage 29, and the sleeve 43 has a through hole at a predetermined portion thereof. 43a is formed. On the other hand, the sleeve 43 is moved back and forth by swinging the control lever 40 according to the amount of depression of the accelerator pedal and the opening / closing operation of the flyweights 46, 46, whereby the internal passage 42a (return passage 29) and The pump chamber 20a is communicated with or cut off from the pump chamber 20a through the through hole 43a, and the fuel pressure in the pump chamber 20a changes in accordance with such an operation to move the piston 34 in the chamber 33 back and forth. The fuel injection timing is retarded or advanced.

In addition to the above configuration, the fuel injection pump 20 is provided with a bypass passage 50 having one end opened to the pump chamber 20a and the other end communicating with the return passage 29.
The bypass passage 50 is provided with a solenoid valve 51 that opens and closes the passage 50, and an orifice 52 that sets the flow rate of the fuel passing through the passage 50 to a set flow rate. The solenoid valve 51 is opened and closed based on the control signal a output from the controller 53. In that case,
The controller 53 sets the engine operating range to a predetermined range based on the rotation speed signal b from the engine speed sensor 54 that detects the engine speed and the load signal c from the load sensor 55 that detects the engine load. It is determined whether or not there is, and the control signal a for opening the valve 51 is output when the determination result indicates that it is in a predetermined region.

Next, the operation of the above embodiment will be described.

First, the operation of the pressure wave supercharger 1 will be briefly described with reference to FIG. 1. As the rotor 3 rotates, a specific groove passage 4 is formed.
When the left end is connected to the intake / exhaust passage 8 via the intake / exhaust port 11 and the right end is connected to the exhaust / introduction passage 12 via the exhaust introduction port 13, the exhaust gas is introduced from the combustion chamber. The high-pressure exhaust gas discharged into the passage 12
The gas flows into the groove-shaped passage 4 through the exhaust gas introduction port 13 and collides with the intake air filled in the passage 4 in the atmospheric pressure state, and along with this, a compression wave of the intake air is generated. Further, from such a state, the exhaust gas moves the intake air to the left and the compression wave propagates to the left, so that the intake air in the groove passage 4 is compressed and the intake air discharge port is compressed. It is supplied to the combustion chamber from the intake passage 11 through the intake air discharge passage 8, whereby the supercharging effect of the supercharger 1 is obtained, and the intake filling effect is enhanced. Then, when the exhaust gas reaches the vicinity of the left end of the groove-shaped passage 4 by discharging almost all the intake air, the passage 4 is closed and the high-pressure exhaust gas remains in the passage 4.

Further, as the rotor 3 further rotates, the specific groove-shaped passage 4 is communicated with the intake introduction passage 6 through the intake introduction port 7 at the left end thereof and the exhaust discharge port 15 at the right end thereof. When communicating with the exhaust discharge passage 14, the exhaust gas in the groove passage 4 expands and is discharged to the exhaust discharge passage 14. At this time, a negative pressure expansion wave is generated and left The exhaust gas is propagated toward the exhaust gas, and the expansion wave sucks the intake air from the introduction passage 6 and moves the exhaust gas to the right, thereby pushing the exhaust gas to the discharge passage 14 to exhaust efficiency or scavenging. Efficiency will be improved. Then, the exhaust gas is surely discharged from the discharge passage 14
The groove-like passage 4 is closed when it is discharged to the. The detailed operation of the supercharger 1 has already been described with reference to FIG. 7, and will not be repeated here.

Next, the basic operation of the fuel injection pump 20 shown in FIG. 2 (conventional fuel injection timing control operation) will be described below.

That is, due to the small depression amount of the accelerator pedal, in a low load region where the tension of the tension coil spring 38 that connects the lever shaft 37 and the control lever 40 is weak, the flyweights 46 ... 46 are affected by the centrifugal force. When the sleeve 43 is opened outward and held at the forward end position, the through hole 43a and the tip opening of the internal passage 42a are aligned and the fuel in the pump chamber 20a flows into the return passage 29. Since the fuel is discharged, the fuel pressure in the pump chamber 20a is maintained in a lowered state. When the fuel pressure drops, the piston 34 provided below the pump chamber 20a
Is advanced by the spring force of the spring 35, and the relative position between the cam disk 24 and the roller 31 delays the reciprocating timing of the plunger 26. Therefore, the fuel injection timing is as shown by symbol (X) in FIG. Is held in a retarded state. Further, when the accelerator pedal is gradually depressed from such a state to shift to the medium load region or the like, the control lever 40 is swung counterclockwise by the spring force of the tension coil spring 38 to retract the sleeve 43. Since the overlapping area between the through hole 43a and the tip opening of the internal passage 42a is gradually narrowed and the fuel pressure in the pump chamber 20a is gradually increased, the piston 34 is also gradually moved backward. Therefore, the fuel injection timing is the third
The angle is gradually advanced as indicated by the symbol (Y) in the figure. When the accelerator pedal is further depressed to reach the high load and high region, the sleeve 43 is further moved backward and the internal passage 42a is closed, so that the fuel injection timing is indicated by a symbol (Z ) As shown by (), it is held in a state advanced to secure a desired engine output.

However, according to such control of the fuel injection timing, the third
It is said that the desired supercharging effect by the pressure wave supercharger 1 cannot be obtained in the medium load region or the medium rotation medium load region where the injection timing is gradually advanced as shown by the symbol (Y) in the figure. Defect occurs. That is, the pressure wave supercharger 1 is
As shown by the symbol (Z) in FIG. 3, a high load region or a high rotation high load region in which the fuel injection timing is advanced,
In other words, in a region where the exhaust gas pressure or the exhaust gas temperature is extremely high, a desired pressure wave (compression wave) is generated in the groove-shaped passage 4 to obtain the maximum supercharging capacity,
Since the arrangement of the intake / exhaust inlets 7 and 13 and the intake / exhaust outlets 11 and 15 and the length of the groove-shaped passages 4 ... Due to the relatively low temperature, the desired pressure wave is not generated, so that a sufficient supercharging capacity cannot be obtained.

Here, considering the exhaust gas temperature, in this engine, that is, the diesel engine, by causing the fuel injection timing to be retarded from the normal timing, so-called afterburn occurs, and the exhaust gas temperature is caused by this afterburning. Has the characteristic of rising. Therefore, in order to improve the supercharging ability of the pressure wave supercharger 1 in the medium-rotation medium-load region, etc., in view of the above characteristics in this engine,
The controller 53 operates as follows.

That is, the controller 53 determines that the operating region of the engine is the high rotation and high load region I shown by the shaded portion in FIG. 4 based on the engine rotation speed indicated by the engine rotation speed signal b and the load indicated by the load signal c. Low rotation and high load area II indicated by dotted lines
The solenoid valve 51 provided in the bypass passage 50 of the fuel injection pump 20 when it is determined that the fuel injection pump 20 is in a predetermined operation region (medium rotation / medium load region, etc.)
Then, a control signal a for opening the valve 51 is output. By such an operation, the bypass passage 50 is opened, and the fuel in the pump chamber 20a flows out to the return passage 29 through the passage 50, so that the fuel pressure in the pump chamber 20a decreases, and Accordingly, the fuel injection timing is the normal or conventional injection timing in this region (indicated by the symbol (Y) in this figure) as indicated by the symbol (Y '), that is, the dotted line in FIG.
Will be retarded by a predetermined amount. Then, after the injection timing is retarded in this way, afterburning occurs, and as shown by the symbol (W '), that is, the dotted line in FIG. 5, the exhaust gas temperature is the normal temperature in this region (the same figure). Therefore, a desired pressure wave (compression wave) is generated in the groove-shaped passage 4 of the pressure supercharger 1 to obtain a sufficient supercharging effect. It will be. This makes it possible to improve acceleration performance or engine response in this region, that is, in the medium-rotation / medium-load region, and to secure a good traveling state.

Further, as described above, the exhaust gas temperature rises in the medium-rotation / medium-load region or the like, so that a desired expansion wave (negative pressure state) is generated even when the exhaust gas is discharged from the pressure wave supercharger 1. Therefore, the exhaust gas is satisfactorily discharged and the scavenging efficiency is improved, whereby the problem that the exhaust gas recirculation amount is excessively increased can be avoided.

Furthermore, by excluding the high-rotation high-load region and the low-rotation low-load region from the region where the fuel injection timing is retarded,
Excessive rise in exhaust gas temperature and accompanying heat damage to the exhaust system when the retard control was performed in the high rotation and high load region, and the retard control was performed in the low rotation and low load region. In this case, the deterioration of the combustion state and the occurrence of misfire can be prevented.

In the above embodiment, the control signal a output from the controller 53 to the solenoid valve 51 is the ON / OFF signal indicating only the opening operation or the closing operation. By using a as a signal for linearly controlling the valve opening amount of the valve 51, the fuel injection timing is gradually retarded or advanced as shown by the chain line in FIG. It may be configured so as to gradually increase or decrease as shown by a chain line in FIG.

(Effects of the Invention) As described above, according to the fuel control device for an engine with a pressure wave supercharger according to the present invention, a sufficient supercharging effect by the supercharger due to the relatively low exhaust gas temperature. In certain areas such as the medium-rotation / medium-load area where it was difficult to obtain, the fuel injection timing was retarded to raise the exhaust gas temperature to the desired temperature. The engine response is improved, and the exhaust gas recirculation amount is reduced in addition to this, and in the high rotation and high load range, etc., the required supercharging effect and The output performance is ensured, and the occurrence of misfire is prevented in the low rotation and low load region and the like, so that the good traveling performance is secured over a wide operating region.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention. FIG. 1 is a sectional view showing a pressure wave supercharger and its passage structure, FIG. 2 is a sectional view of a fuel injection pump, and FIG. 3 is a load. Is a graph showing the characteristic of the fuel injection timing with respect to the above, FIG. 4 is a schematic explanatory view showing the control region, and FIG. 5 is a graph showing the characteristic of the exhaust gas temperature with respect to the load. FIG. 6 is a schematic perspective view showing the pressure wave supercharger and its installation state, and FIG. 7 is a development view of a rotor in the pressure wave supercharger for showing the operation of the pressure wave supercharger. 1 ... Pressure wave supercharger, 20 ... Fuel injection pump, 50 ... Bypass passage, 51 ... Solenoid valve, 53 ... Controller.

Claims (1)

[Claims] 1. A pressure wave supercharger and a fuel injection pump are provided, which are configured to obtain a supercharge effect by compressing intake air using a pressure wave generated based on the pressure of exhaust gas. In an engine configured to control the fuel injection timing by the fuel injection pump to a predetermined value based on the above, when the operating region is in a predetermined region excluding a low rotation low load region and a high rotation high load region, A fuel injection timing control device for a pressure wave supercharged engine, comprising control means for retarding the fuel injection timing with respect to the predetermined value.