JP3791100B2 - Water injection amount control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a water injection amount control device suitable for use in a water injection type diesel engine that injects fuel and water into a combustion chamber.
[0002]
[Prior art]
In a diesel engine, the combustion is performed by so-called in-cylinder air compression ignition, so the generation mechanism of each component contained in the exhaust gas is different from that in the case of gasoline premixed combustion. That is, in a diesel engine, combustion is generally performed in an excess air state, and the emission concentrations of HC (hydrocarbon) and CO (carbon monoxide) are relatively low, whereas the combustion temperature is high. Therefore, a relatively large amount of NOx (nitrogen oxide) is generated.
[0003]
Further, after the fuel injection is performed, the fuel vapor or the extreme over-concentration mixture is locally exposed to a high temperature atmosphere, so that the fuel molecules are thermally decomposed and carbon particles are easily formed. For this reason, a large amount of soot is contained in the exhaust gas. In particular, when the load is high, the combustion temperature is high, the generation of NOx is promoted, and the fuel density is higher than when the load is low. Soot is discharged.
[0004]
Therefore, a so-called water injection type diesel engine has been proposed in which fuel and water are mixed and injected into a combustion chamber to cause combustion. In this water injection type diesel engine, water is injected into the combustion chamber together with fuel at the time of fuel injection, whereby the combustion temperature is lowered and generation of NOx can be suppressed. In addition, a small explosion due to water vaporization, that is, a water divergence phenomenon generates a vortex in the combustion chamber, improving the combustion efficiency and suppressing the generation of soot. Furthermore, the fuel efficiency is improved by the improvement of the combustion efficiency.
[0005]
[Problems to be solved by the invention]
By the way, in such a water injection type diesel engine, the amount of fuel and water injected into the combustion chamber is controlled in accordance with the operating state of the engine (specifically, the engine speed and the engine load). Further, the water injection diesel engine is provided with two high-pressure pumps, a fuel injection pump that pressurizes fuel and a water supply pump that pressurizes water. Among these, the fuel injection pump is configured in the same manner as a fuel injection pump provided in a normal diesel engine, and the fuel injection amount is changed by changing the rack position. The water supply pump is also configured in substantially the same manner as such a fuel injection pump, and the amount of water injection is also controlled by changing the rack position.
[0006]
For example, in FIG. 6, when the engine operating state changes from the state (1) (first operating state) to the operating state (2) (second operating state) (indicated by an arrow a in the figure), When the operation state (1) is changed from the operation state (2) (first operation state) to the operation state (second operation state) (1) (indicated by an arrow b in the figure), the time chart as shown in FIG. Then, fuel injection and water injection are controlled.
[0007]
That is, as shown in FIG. 7 (d), when it is detected that the operating state of the engine has changed from the state (1) to the state (2), first, a rack of the water supply pump is detected by a controller (not shown). The position is changed from the rack position Rww1 suitable for the first operation state to the rack position Rww2 suitable for the second operation state (t = ta1).
As a result, as shown in FIG. 7B, the water injection amount qw increases to the injection amount qw2 corresponding to the rack position Rww2.
[0008]
Next, as shown in FIG. 7C, after issuing a control signal to the water supply pump, the controller delays the control cycle τ (t = ta2) and increases the fuel injection amount in order to increase the fuel injection amount. The rack position of the pump is changed from the rack position Rwf1 suitable for the first operation state to the rack position Rwf2 suitable for the second operation state.
Note that the reason why the rack position change signal to the fuel injection pump is delayed by the control period τ is simply because a signal cannot be output at the same time in the control of the controller. Will occur. Hereinafter, this control cycle is referred to as a control interval.
[0009]
By the way, when such a control interval τ exists, as shown in FIG. 7A, the fuel injection amount temporarily decreases during the period from ta1 to ta2. This is because, until the rack position of the fuel injection pump is changed, that is, until t = ta2, the total injection amount of fuel and water remains unchanged, so that the water injection amount increased during the period from ta1 to ta2. As a result, the fuel injection amount is reduced by that amount. Then, there is a problem that the output torque of the engine decreases due to such a decrease in the fuel injection amount, and so-called breathing occurs.
[0010]
Contrary to the above, when it is detected that the engine operating state has changed from state (2) to state (1), the rack position of the water supply pump is set to the second operating state by the controller. The rack position Rww2 suitable for the first operation state is changed to the rack position Rww1 suitable for the first operating state (t = tb1), so that the water injection amount is changed to the rack position Rww1 of the water supply pump as shown in FIG. The injection amount qw1 according to.
[0011]
Then, after delaying the control interval τ after issuing the control signal to the water supply pump (t = tb2), the rack position of the fuel injection pump is suitable for the second operation state in order to reduce the fuel injection amount. The rack position is changed from Rwf2 to the rack position Rwf1 suitable for the first operating state.
In this case, contrary to the above, the fuel injection amount temporarily increases in the period from tb1 to tb2. That is, when the rack position of the fuel injection pump is changed (t = tb2), the total injection amount of fuel and water remains unchanged, and as a result, during the period from tb1 to tb2, the amount of water injection decreases. Only the fuel injection amount will increase. Then, there is a possibility that black smoke may be discharged by excessively injecting the fuel.
[0012]
The present invention has been devised in view of such problems, and suppresses rapid fluctuations in the rack positions of the water supply pump and the fuel injection pump accompanying changes in the operating state of the engine, thereby reducing breathing and blackness due to torque reduction. An object of the present invention is to provide a water injection amount control device capable of suppressing smoke emission as much as possible.
[0013]
[Means for Solving the Problems]
For this reason, the water injection amount control device according to the first aspect of the present invention includes a water supply pump that changes the amount of water supplied by changing the rack position, and the water supplied by the water supply pump. In a water injection type engine that can inject fuel into the combustion chamber of the engine, an operating state detecting means for detecting the operating state of the engine, and a control means for setting the injection amount of the water based on detection information from the operating state detecting means And when the operating state of the engine changes from the first operating state to the second operating state, the target in the second operating state is changed from the rack position in the first operating state of the water supply pump. When the rack position change amount up to the rack position is larger than a predetermined amount, the control means causes the water supply pump so that the single rack position change amount of the water supply pump is smaller than the predetermined amount. Changing the rack position is characterized in that it is configured to be divided into a plurality of times.
[0014]
Further, in the water injection amount control device according to the second aspect of the present invention, in addition to the configuration according to the first aspect, the control means is configured such that the control means is configured to perform the second operation based on detection information from the operating state detection means. Target rack position setting means for obtaining a target rack position of the water supply pump in the operating state, and a rack position for calculating a rack position change amount from the rack position to the target rack position in the first operating state of the water supply pump When the change amount calculating means and the rack position change amount are larger than a predetermined amount, the rack position change amount for one time of the water supply pump is set smaller than the predetermined amount, and the rack of the water supply pump is set. And rack position change amount dividing means for dividing the position change into a plurality of times.
[0015]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the predetermined amount is set by a map of engine speed and load. It is said.
According to a fourth aspect of the present invention, in addition to the configuration of the second or third aspect, the water injection type engine changes the rack position in addition to the water supply pump. A fuel injection pump for changing the amount of fuel supplied, and the control means changes the rack position of the fuel injection pump when the change of the rack position of the water supply pump is divided into a plurality of times. As in the case of the water supply pump, fuel injection pump rack position change amount dividing means is provided for dividing the fuel supply pump into a plurality of times.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a water injection amount control device as an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram focusing on the main part, FIG. 2 is a map showing characteristics of the water injection amount, FIG. 3 is a map for setting the rack position of the fuel injection pump.
[0017]
In FIG. 1, reference numeral 1 denotes a fuel injection nozzle of a so-called water injection type diesel engine, which is attached to a cylinder head (not shown) for each cylinder. The fuel injection nozzle 1 mixes and injects fuel and water into the combustion chamber.
A water supply pump 40 is connected to the fuel injection nozzle 1 via a water pipe (water supply path) 30 and a fuel injection pump 70 is connected to the fuel injection nozzle 1 via a fuel pipe (fuel supply path) 31. Yes.
[0018]
Here, the water supply pump 40 and the fuel injection pump 70 have substantially the same configuration. That is, a rack actuator 81 is attached to the fuel injection pump 70 as shown in the figure, and the fuel injection pump 70 injects fuel by moving the rack (not shown) of the fuel injection pump 70 by the rack actuator 81. The amount of fuel supplied to the nozzle 1 is changed.
[0019]
The water supply pump 40 is equipped with a rack actuator 80, and the rack actuator 80 moves the rack (not shown) of the water supply pump 40 to supply the fuel injection nozzle 1 from the water supply pump 40. The amount of water used is changed.
Then, by changing the amount of fuel and water supplied from these pumps 40 and 70 to the fuel injection nozzle 1, the amount of fuel and water actually injected from the fuel injection nozzle 1 is changed. ing.
[0020]
The rack actuators 80 and 81 are electrically connected to a controller (control means) 90 described later, and the rack positions of the water supply pump 40 and the fuel injection pump 70 are controlled according to a control signal from the controller 90. It has become so. The pumps 40 and 70 can continuously change the discharge amount from 0 to the injection amount at the maximum engine load according to the rack position.
[0021]
Next, the main part of the present invention will be described. The controller (control means) 90 includes an engine speed sensor 91 for detecting the engine speed and an engine for detecting the engine load, as shown in FIG. A load sensor 92 is connected. The engine load sensor 92 detects the engine load by detecting the amount of depression of the accelerator pedal, for example. The engine speed sensor 91 and the engine load sensor 92 have a function as an operating state detecting unit 50 that detects the operating state of the engine.
[0022]
Further, in the controller 90, a water supply pump control unit 90A and a fuel injection pump control unit 90B are provided. These control units 90A and 90B control the operation of the rack actuators 80 and 81 based on the detection information from the operation state detection means 50, respectively, and control the rack position of each pump 40 and 70. Thus, the flow rate of the fluid (water, fuel) discharged from each pump 40, 70 is controlled.
[0023]
Specifically, in each of the control units 90A and 90B, based on the detection information from the operating state detection means 50 (the engine speed sensor 91 and the engine load sensor 92), the engine operating state is in a certain state (first If it is determined whether the engine operating state has changed from the operating state) to another state (second operating state), the water injection amount and the fuel injection amount according to the engine operating state are An operation control signal is output to each rack actuator 80, 81. Here, the state immediately before the engine operating state changes is referred to as a first operating state, and the state immediately after the engine operating state changes is referred to as a second operating state. Therefore, for example, when the engine operating state changes in the direction of arrow a shown in FIG. 6, the state (1) corresponds to the first operating state, and the state (2) corresponds to the second operating state. To do. When the engine operating state changes in the direction of the arrow b shown in FIG. 6, the state (2) corresponds to the first operating state, and the state (1) corresponds to the second operating state. .
[0024]
Now, of the water supply pump control unit 90A and the fuel injection pump control unit 90B, first, the water supply pump control unit 90A will be described. The water supply pump control unit 90A includes a target rack as shown in FIG. Position setting means 60, rack position change amount calculating means 61, and rack position change amount dividing means 62 are provided.
Among these, the target rack position setting means 60 obtains the target rack position Rww2 of the water supply pump 40 in the second operation state based on the detection information from the operation state detection means 50.
[0025]
Here, the target rack position setting means 60 stores a map (see FIG. 2) for obtaining the target rack position Rww2. In this map, the ratio of the optimal water injection amount to the fuel injection amount is stored in accordance with the engine speed and the engine load, and the target rack position setting means 60 determines the engine speed and the engine load from this map. Based on this, the optimum target rack position Rww2 in the second operating state is set.
[0026]
Further, the rack position change amount calculation means 61 extends from the rack position (that is, the current rack position) Rww1 of the water supply pump 40 in the first operation state to the target rack position Rww2 set by the target rack position setting means 60. Rack position change amount ΔRww (= | Rww2−Rww1 |) is calculated.
The rack position change amount dividing unit 62 compares the rack position change amount ΔRww calculated by the rack position change amount calculating unit 61 with the predetermined amount ΔRwwmax, and the rack position change amount ΔRww is larger than the predetermined amount ΔRwwmax. In such a case, the change in the rack position of the water supply pump 40 is divided into a plurality of times by setting the amount of change in the rack position of the water supply pump 40 to be smaller than a predetermined amount ΔRwwmax.
[0027]
The predetermined amount ΔRwwmax is a maximum value of one rack position change amount set by the engine speed and the engine load, and is a three-dimensional map (not shown) (engine speed, engine load and ΔRwwmax). ). Further, the predetermined amount ΔRwwmax is considered to be such that when the amount of change in one rack position is greater than or equal to the maximum value ΔRwwmax, engine torque fluctuations increase, causing engine breathing and black smoke emission. This is the rack position change amount.
[0028]
That is, in this apparatus, when the rack position change amount ΔRww is larger than the predetermined amount ΔRwwmax, the single rack position change amount of the water supply pump 40 is set to be smaller than the predetermined amount ΔRwwmax, and the water supply pump By dividing the change of the rack position of 40 into a plurality of times, the torque fluctuation when the engine operating state changes is suppressed as much as possible, and the breath of the engine and the discharge of black smoke are prevented. .
[0029]
Next, the fuel injection pump control unit 90B will be described. The fuel injection pump control unit 90B includes a fuel injection pump control unit 90B that is configured to change the fuel injection pump 70 when the engine operating state changes from the first operating state to the second operating state. Based on the information from the target rack position setting means 63 for setting the target rack position Rwf2, and the rack position change amount dividing means 62 provided in the target rack position setting means 63 and the water supply pump controller 90A described above, Rack position change amount dividing means 64 for dividing the change of the rack position of the fuel injection pump 70 into a plurality of times is provided.
[0030]
Here, the target rack position setting means 63 sets the rack change amount ΔRwf of the fuel injection pump 70 based on the rack position Rww of the water supply pump 40 set by the target rack position setting means 60 of the water supply pump 40. For example, a map as shown in FIG. 3 is stored.
Further, the rack position change amount dividing means 64, when the rack position change of the water supply pump 40 is divided into a plurality of times based on the information from the rack position change amount dividing means 62 of the water supply pump control unit 90A. Similarly, the rack position change of the fuel injection pump 70 is divided into a plurality of times.
[0031]
As a result, when the rack position change amount ΔRww of the water supply pump 40 is larger than the predetermined amount ΔRwwmax when the engine operating state changes, the change of the rack position of the fuel injection pump 70 also changes the rack position of the water supply pump 40. It is divided into the same number of changes.
Since the water injection amount control device as one embodiment of the present invention is configured as described above, when the operating state of the engine changes, for example, according to the time chart as shown in FIG. Water jet control is performed.
[0032]
First, the case where the operating state of the engine changes from the state (1) (first operating state) shown in FIG. 6 to the state (2) (second operating state) will be described.
The controller 90 determines whether or not the engine operating state has changed based on the engine speed information and the engine load information from the engine speed sensor 91 and the engine load sensor 92, and determines that the engine operating state has changed. In this case, the target rack position setting means 60 sets the target rack position Rww2 of the water supply pump 40 from the map as shown in FIG.
[0033]
Then, the rack position change amount calculation means 61 calculates the rack position change amount ΔRww (= Rww2−Rww1) from the current rack position Rww1 of the water supply pump 40 to the target rack position Rww2. Further, the rack position change amount dividing means 62 determines whether or not the rack position change amount ΔRww is larger than a predetermined amount ΔRwwmax. The predetermined amount ΔRwwmax is set based on the engine speed and the engine load from a map (not shown).
[0034]
Here, when the rack position change amount ΔRww is larger than the predetermined amount ΔRwwmax, the rack position of the water supply pump is changed so that one rack position change amount of the water supply pump is smaller than the predetermined amount ΔRwwmax. Divided into multiple times. In this case, specifically, the indicated rack position Rwwd of the first water supply pump 40 is set as Rww1 + ΔRwwmax.
[0035]
Thereby, as shown in the time chart of FIG. 4D, the rack position of the water supply pump 40 is set to Rww1 + ΔRwwmax at the control start time t = ta1. As a result, the water injection amount qw becomes qw1 + Δqw as shown in FIG. 4 (b).
On the other hand, as shown in FIG. 4A, the fuel injection amount qf temporarily decreases as the water injection amount increases. This is because the total injection amount of fuel and water remains unchanged until the rack position of the fuel injection pump 70 is changed (that is, until t = ta2), so the period from ta1 to ta2 is As a result, the fuel injection amount is reduced by the amount that the water injection amount is increased.
[0036]
However, in this apparatus, since the rack position change of the water supply pump 40 is suppressed once so that the increase in the water injection amount is equal to or less than the predetermined amount ΔRwwmax, such a decrease in the fuel injection amount can also be suppressed. Thus, torque reduction can be suppressed to a minimum, and so-called breathing can be prevented.
Then, the rack position Rwf of the fuel injection pump 70 is controlled in the next control cycle (t = ta2) of the controller 90. At this time, the rack position Rwf of the fuel injection pump 70 is set by the target rack position setting means 63 of the fuel injection pump control unit 90B, but in the rack position change amount dividing means 64 of the fuel injection pump control unit 90B. When the information from the rack position change amount dividing means 62 of the water supply pump control unit 90A is taken in and the change of the rack position of the water supply pump 40 is divided into a plurality of times, the rack position change of the water supply pump 40 is changed. In the same manner as in the above division, the change of the rack position of the fuel injection pump 70 is divided into a plurality of times.
[0037]
That is, as shown in FIG. 4C, at t = ta2, the rack position Rwf of the fuel injection pump 70 is set to Rwf1 + ΔRwf. As a result, as shown in FIG. 4A, the fuel injection amount qf becomes qf1 + Δqf.
Further, in the next control period (t = ta3) of the controller 90, the rack position Rww1 + ΔRwwmax of the water supply pump 40 is changed again.
[0038]
At this time, if the difference [| Rww2− (Rww1 + ΔRwwmax) |] between the previous designated rack position Rwwd (= Rww1 + ΔRwwmax) and the target rack position Rww2 is larger than the predetermined amount ΔRwwmax, the designated rack position Rwwd is set again. The rack position Rww1 + ΔRwwmax plus a predetermined amount ΔRwwmax is set as a new indicated rack position Rwwd (t = ta3). Hereinafter, the change in the rack position of the water supply pump 40 is divided into a plurality of times until the difference between the rack position Rwwd and the target rack position Rww2 that have been changed immediately before becomes smaller than a predetermined amount ΔRwwmax.
[0039]
When the difference between the previous designated rack position Rwwd and the target rack position Rww2 becomes smaller than a predetermined amount ΔRwwmax, the target rack position Rww2 is set as the final designated rack position Rwwd. That is, the rack position change of the water supply pump 40 is repeated n times until Rww1 + n · ΔRwwmax> Rww2 is satisfied.
In the example shown in FIG. 4, the second indicated rack position Rwwd of the water supply pump 40 is the target rack position Rww2. That is, in this case, as shown in FIG. 4 (d), at t = ta3, the indicated rack position Rwwd of the water supply pump 40 is set to the target rack position Rww2, and as a result, shown in FIG. 4 (b). Thus, the water injection amount qw changes from qw1 to qw2 step by step.
[0040]
At this time, as shown in FIG. 4 (a), the fuel injection amount qf temporarily decreases as the water injection amount qw increases as in the case of t = ta1, but the next control cycle (t = Ta4), the rack position of the fuel injection pump 70 is set to Rwf2, so that the water and fuel injection amounts are in accordance with the second operating state.
On the other hand, the case where the operating state of the engine changes from the state (2) (first operating state) shown in FIG. 6 to the state (2) (second operating state) will be described. And is controlled in substantially the same manner. In the following cases, subscript 2 represents the first operating state, and subscript 1 represents the second operating state.
[0041]
First, the controller 90 sets the target rack position Rww1 of the water supply pump 40 in the target rack position setting means 60, and then the rack position change amount calculation means 61 sets the current rack position Rww2 of the water supply pump 40. The rack position change amount ΔRww (= | Rww1−Rww2 |) from the target rack position Rww1 is calculated. Further, the rack position change amount dividing means 62 determines whether or not the rack position change amount ΔRww is larger than a predetermined amount ΔRwwmax set based on the engine speed and the engine load from a map (not shown).
[0042]
When the rack position change amount ΔRww is larger than the predetermined amount ΔRwwmax, the rack position of the water supply pump is changed multiple times so that the rack position change amount of one water supply pump is smaller than the predetermined amount ΔRwwmax. Divided. In this case, specifically, the indicated rack position Rwwd of the first water supply pump 40 is set as Rww2−ΔRwwmax.
[0043]
As a result, as shown in the time chart of FIG. 4D, at the control start time t = tb1, the rack position of the water supply pump 40 is set to Rww2−ΔRwwmax. As shown in b), qw2−Δqw.
On the other hand, as shown in FIG. 4A, the fuel injection amount qf temporarily increases as the water injection amount decreases. This is because the total injection amount of fuel and water remains unchanged until the rack position of the fuel injection pump 70 is changed (that is, until t = tB2), so the period from tB1 to tB2 is As a result, the fuel injection amount increases as the water injection amount decreases.
[0044]
However, in this apparatus, since one rack position change of the water supply pump 40 is suppressed so that the decrease in the water injection amount is equal to or less than the predetermined amount ΔRwwmax, such an increase in the fuel injection amount is also suppressed. Therefore, the emission of black smoke can be minimized.
Then, the rack position Rwf of the fuel injection pump 70 is controlled in the next control cycle (t = tb2) of the controller 90. At this time, the rack position Rwf of the fuel injection pump 70 is set by the target rack position setting means 63 of the fuel injection pump control unit 90B, but in the rack position change amount dividing means 64 of the fuel injection pump control unit 90B. When the information from the rack position change amount dividing means 62 of the water supply pump control unit 90A is taken in and the change of the rack position of the water supply pump 40 is divided into a plurality of times, the rack position of the water supply pump 40 is Similar to the change division control, the change in the rack position of the fuel injection pump 70 is divided into a plurality of times.
[0045]
That is, as shown in FIG. 4C, at t = tb2, the rack position Rwf of the fuel injection pump 70 is set to Rwf2−ΔRwf. As a result, as shown in FIG. 4A, the fuel injection amount qf becomes qf2−Δqf.
Further, in the next control cycle (t = tb3) of the controller 90, the rack position Rww2−ΔRwwmax of the water supply pump 40 is changed again.
[0046]
At this time, when the difference [| Rww1− (Rww2−ΔRwwmax) |] between the previous designated rack position Rwwd (= Rww2−ΔRwwmax) and the target rack position Rww1 is larger than the predetermined amount ΔRwwmax, the designated rack position Rwwd is again generated. Is obtained by subtracting the previous rack position Rww2−ΔRwwmax by a predetermined amount ΔRwwmax as a new indicated rack position Rwwd (t = tb3). Hereinafter, the rack position of the water supply pump 40 is divided into a plurality of times until the difference between the rack position Rwwd changed immediately before and the target rack position Rww1 becomes smaller than a predetermined amount ΔRwwmax.
[0047]
When the difference between the previous designated rack position Rwwd and the target rack position Rww1 becomes smaller than a predetermined amount ΔRwwmax, the target rack position Rww1 is set as the final designated rack position. That is, the rack position change of the water supply pump 40 is repeated n times until Rww2−n · ΔRwwmax <Rww1 is satisfied.
In the example shown in FIG. 4, the second indicated rack position Rwwd of the water supply pump 40 is the target rack position Rww1. That is, in this case, as shown in FIG. 4 (d), at t = tb3, the indicated rack position Rwwd of the water supply pump 40 is set to the target rack position Rww1, and as a result, shown in FIG. 4 (b). Thus, the water injection amount qw is gradually changed from qw2 to qw1.
[0048]
At this time, as shown in FIG. 4A, the fuel injection amount qf temporarily increases as the water injection amount qw decreases as in the case of t = tb1, but the next control cycle (t = Tb4), the rack position of the fuel injection pump 70 is set to Rwf1, so that the water and fuel injection amounts correspond to the second operating state.
By the way, in such a water injection amount control device, rack position control of the water supply pump 40 and the fuel injection pump 70 is performed according to a flowchart as shown in FIG.
[0049]
That is, first, in step S1, the target rack position Rww2 of the water supply pump 40 is read from the three-dimensional map as shown in FIG. 2 based on the engine speed and the engine load, and the flag F is set to zero. Next, proceeding to step S2, the maximum value ΔRwwmax of one rack position change amount is read from a three-dimensional map (not shown) based on the engine speed and the engine load.
[0050]
Then, proceeding to step S3, the amount of change | Rww2-Rww1 | from the current rack position Rww1 to the target rack position Rww2 and the maximum value ΔRwwmax of the rack position change amount of the water supply pump 40 obtained in step S2 Compare the size of. If the rack position change amount | Rww2−Rww1 | is smaller than the maximum value ΔRwwmax, the process proceeds to step S4 to set the indicated rack position Rwwd of the water supply pump 40 to the target rack position Rww2. , Flag F is set to 1, and then the process proceeds to step S6.
[0051]
On the other hand, if it is determined in step S3 that the rack position change amount | Rww2−Rww1 | is larger than the maximum value ΔRwwmax, the process proceeds to step S5, and the indicated rack position Rwwd is set to Rww1 + ΔRwwmax. Further, Rww1 = Rwwd is set so that ΔRwwmax is added again to the previous designated rack position Rwwd when the routine goes through step S5 again in the subsequent routines.
[0052]
In step S6, the rack position of the water supply pump 40 is driven to the indicated rack position Rwwd, and water is injected at a predetermined water injection amount.
Thereafter, the process proceeds to step S7, where the rack position increase ΔRwf of the fuel injection pump 70 is set according to the injection amount of the water supply pump 40. At this time, the rack position increment ΔRwf of the fuel injection pump 70 is set based on the rack position Rww of the water supply pump 40 controlled in step S6. In step S8, the rack position Rwf of the fuel injection pump 70 is set to Rwf1 + ΔRwf, and fuel injection control is executed.
[0053]
Thereafter, in step S9, it is determined whether or not the flag is F = 1. If F = 1, the process returns. If not, the process returns to step S3, and steps S3 to S8 are repeatedly executed until F = 1. To do.
In the water injection amount control device of the present invention, the rack positions of the water injection pump 40 and the fuel injection pump 70 are controlled in this way, so that rapid fluctuations in the rack positions of the water supply pump 40 and the fuel injection pump 70 are suppressed. There are advantages that can be made. Specifically, when the engine operating state changes, the fuel injection amount temporarily drops suddenly or excessive fuel injection can be suppressed. As a result, there is an advantage that breathing due to a decrease in engine torque and emission of black smoke can be suppressed.
[0054]
Further, according to the water injection amount control device of the present apparatus, it is not necessary to provide new parts or the like with respect to the conventional water injection type engine, and it is only necessary to change the control logic, resulting in an increase in cost and weight. There is also an advantage that there is nothing.
Furthermore, since the predetermined amount ΔRwwmax is set here according to the engine speed and the engine load, there is an advantage that fine rack position control according to the engine operating state can be performed.
[0055]
【The invention's effect】
As described above in detail, according to the water injection amount control device of the present invention as set forth in claim 1, it is possible to suppress a rapid change in the rack position of the water supply pump, thereby changing the engine operating state. Sometimes, there is an advantage that it is possible to suppress breathing due to a decrease in engine torque and emission of black smoke.
[0056]
Further, according to the water injection amount control device of the present invention described in claim 2, in addition to the same advantages as described above, it is not necessary to provide new parts or the like for the conventional water injection type engine, and the control logic is provided. Since it only needs to be changed, there is an advantage that neither increase in cost nor increase in weight is caused.
Further, according to the water injection amount control device of the present invention as set forth in claim 3, there is an advantage that fine rack position control according to the engine operating state can be performed.
[0057]
Further, according to the water injection amount control device of the present invention as set forth in claim 4, there is an advantage that rapid fluctuations in the rack position of the water supply pump and the fuel injection pump can be suppressed. As a result, when the engine operating state changes, it is possible to suppress a sudden drop in the fuel injection amount or excessive fuel injection. There is an advantage that smoke emission can be suppressed. Moreover, since there is no need to provide new parts or the like and only the control logic needs to be changed with respect to the conventional water injection type engine, there is an advantage that neither an increase in cost nor an increase in weight is caused.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic block diagram focusing on the main configuration of a water injection amount control device as one embodiment of the present invention.
FIG. 2 is a map showing the characteristics of the water injection amount in the water injection amount control device as one embodiment of the present invention.
FIG. 3 is a map for setting a rack position of a fuel injection pump in a water injection amount control device as one embodiment of the present invention.
FIG. 4 is a time chart for explaining the operation of the water injection amount control apparatus as one embodiment of the present invention.
FIG. 5 is a flowchart for explaining the operation of the water injection amount control apparatus as one embodiment of the present invention.
FIG. 6 is a diagram for explaining a change in a general engine operating state;
FIG. 7 is a time chart for explaining the operation of a conventional water injection amount control device.
[Explanation of symbols]
1 Fuel injection nozzle 1
30 water pipe (water supply channel)
31 Fuel pipe (fuel supply path)
40 Water supply pump
50 Operating state detection means
60 Water supply pump target rack position setting means
61 Water supply pump rack position change amount calculating means
62 Water supply pump rack position change amount dividing means
63 Fuel injection pump target rack position setting means
64 Fuel injection pump rack position change amount dividing means
70 Fuel injection pump
80, 81 rack actuator
90 controller (control means)
90A water supply pump controller
90B Fuel injection pump controller
91 Engine speed sensor
92 Engine load sensor

Claims (4)

In a water injection engine that includes a water supply pump that changes an amount of water supplied by changing a rack position and can inject the water supplied by the water supply pump into a combustion chamber of the engine.
An operating state detecting means for detecting the operating state of the engine;
Control means for setting the water injection amount based on detection information from the operating state detection means,
When the operating state of the engine changes from the first operating state to the second operating state, the rack position of the water supply pump from the rack position in the first operating state to the target rack position in the second operating state If the rack position change amount is larger than the predetermined amount,
The control means is configured such that the change in the rack position of the water supply pump is divided into a plurality of times so that the amount of change in the rack position of the water supply pump once is smaller than the predetermined amount. A water injection amount control device. The control means
Target rack position setting means for determining a target rack position of the water supply pump in the second operation state based on detection information from the operation state detection means;
Rack position change amount calculating means for calculating a rack position change amount from the rack position to the target rack position in the first operation state of the water supply pump;
When the rack position change amount is larger than a predetermined amount, the single rack position change amount of the water supply pump is set smaller than the predetermined amount, and the rack position change of the water supply pump is changed a plurality of times. Rack position change amount dividing means for dividing into
The water injection amount control device according to claim 1, comprising: The water injection amount control device according to claim 1 or 2, wherein the predetermined amount is set by a map of engine speed and load. In addition to the water supply pump, the water injection engine includes a fuel injection pump that changes an amount of fuel supplied by changing a rack position.
The control means
Fuel injection pump rack position change amount dividing means for dividing the change of the rack position of the fuel injection pump into a plurality of times in the same manner as the water supply pump when the change in the rack position of the water supply pump is divided into a plurality of times The water injection amount control device according to claim 2 or 3, characterized by comprising:

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