JPH1089093A - Intake throttle valve controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent poor acceleration from being generated by properly controlling the opening of an intake throttle valve in accelerating of an engine. SOLUTION: An intake throttle valve 6 is provided on an intake passage 2 of a diesel engine 1, the opening of the throttle valve 6 is set on the basis of a product of the engine speed multiplied by the engine fuel injection amount by a controller (ECU) 30. In the acceleration of the engine, the set throttle valve opening is increased and corrected according to a value of the accelerator opening ACCP. Since the intake throttle valve opening is increased and corrected according to the degree of acceleration of the engine, new air is sufficiently supplied to the engine, and exhaust gas smoke and poor acceleration problems are not posed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake throttle valve control device for an internal combustion engine, and more particularly to an intake throttle valve control device suitable for use in a diesel engine that performs exhaust gas recirculation (EGR).

[0002]

2. Description of the Related Art Exhaust gas recirculation (E) for recirculating a part of engine exhaust gas to an engine intake passage and restricting the flow of fresh air into the engine.
GR) devices are known. By performing EGR, the amount of fresh air can be reduced during intake without reducing the total amount of intake air flowing into the engine combustion chamber.
By lowering the engine combustion temperature than usual, it is possible to reduce the amount of NO _X generated by combustion.

[0003] On the other hand, in a diesel engine, combustion in which the excess air ratio is extremely high under normal operating conditions (excess air ratio λ ≒)
30), it is necessary to recirculate a larger amount of exhaust gas to the intake passage than in a gasoline engine in order to maximize the effect of EGR. For this reason,
An intake throttle valve is provided in the intake passage of the diesel engine,
An EGR device that enables a large amount of EGR by deactivating the intake throttle valve to a predetermined opening when performing GR and recirculating exhaust gas to an intake passage downstream of the throttle valve has been devised. According to such an EGR device, by closing the intake throttle valve to a predetermined opening degree, the amount of intake air (fresh air) passing through the intake passage decreases, and the negative pressure of the intake passage downstream of the throttle valve increases. (Pressure decreases) and the amount of recirculated exhaust gas increases, so that a larger amount of exhaust gas can be recirculated than usual.

Since the intake throttle valve restricts the flow of fresh air into the engine, the opening degree of the intake throttle valve is controlled in accordance with the operating state of the engine to prevent a decrease in engine performance. There is a need to. Therefore, a control device of the intake throttle valve that controls the intake throttle valve according to the engine operating state, particularly, the engine load is used. An example of this type of intake throttle valve control device is disclosed in, for example, JP-A-55-109754. The intake throttle valve control device of this publication detects the engine speed and the engine load, and sets the intake throttle valve opening based on the engine speed and the load. As described above, by controlling the intake throttle valve opening based on the engine speed and the load, it becomes possible to perform a large amount of EGR while preventing a decrease in engine performance.

[0005]

However, in a diesel engine, the opening degree of the intake throttle valve is controlled based only on the engine speed and the engine load as in the apparatus disclosed in Japanese Patent Application Laid-Open No. 55-109754. In some cases, problems occur during transient operation such as rapid acceleration. Generally, the intake pressure (intake pipe negative pressure) is used as a parameter representative of the engine load (load torque). Therefore, the intake throttle valve opening is used by using the intake pressure together with the engine speed as a parameter representing the load. Let us consider the case where is controlled as an example. In this case, even when the driver depresses the accelerator pedal during sudden acceleration of the engine, the engine speed does not increase instantaneously. For this reason, at the start of the engine acceleration, the intake throttle valve opens only slightly according to the increasing speed of the engine speed. Therefore, the rise of the intake pressure due to the opening of the intake throttle valve is also delayed, and the rise of the engine speed is further delayed due to the shortage of the fresh air inflow. Therefore, if the opening degree of the intake throttle valve is controlled based on the engine speed and the engine intake pressure, the rise of the rotation speed and the intake pressure is slow, so that the opening degree of the intake throttle valve even at the time of rapid acceleration is controlled. Increases only gradually, and the amount of fresh air flowing into the engine increases only relatively slowly. on the other hand,
In the case where the fuel injection amount is controlled according to the accelerator opening (accelerator pedal depression amount), if the driver depresses the accelerator pedal during rapid acceleration, the amount of fresh air flowing into the engine does not increase. Nevertheless, since the fuel rapidly increases in accordance with the accelerator opening, the fuel supply amount becomes excessive with respect to the fresh air amount, and a problem occurs that exhaust smoke is generated during acceleration.

In order to prevent the generation of smoke during acceleration, it is also possible to limit the fuel injection amount in accordance with the amount of fresh air flowing in and the intake pressure when fuel is increased during acceleration or the like. However, when the opening degree of the intake throttle valve is controlled based on the engine speed and the intake pressure as described above, the increase in both the engine speed and the intake pressure is delayed during acceleration, so that the fuel injection amount is reduced to prevent generation of smoke. Since the fuel injection amount is limited to the upper limit and the increase in the fuel injection amount is also delayed, the fuel injection amount does not increase even though the driver requests rapid acceleration, and poor acceleration occurs. . In an engine equipped with a supercharger such as an exhaust turbocharger, the delay in boosting the boost pressure during acceleration is added to the above, so the increase in engine speed and intake pressure is further delayed, and exhaust smoke and poor acceleration occur. It will be easier.

As a parameter representative of the engine load torque, there is a fuel supply amount to the engine (for example, a fuel injection amount per one time) in addition to the intake pressure. Even when the control is performed according to the injection amount, the same problem as described above occurs. That is, at the time of rapid acceleration, even if the fuel injection amount increases suddenly, the engine speed does not increase instantaneously. For this reason, the increase in the opening degree of the intake throttle valve is slowed down as described above, and the fresh air flow rate is insufficient. Therefore, if only the fuel injection amount sharply increases, a problem of smoke generation occurs. If the fuel injection amount has an upper limit for preventing smoke generation, the actual fuel injection will not be larger than this upper limit, so that both the rotation speed and the fuel injection amount will be delayed, and the intake throttle The increase in the opening degree of the valve is delayed, and poor acceleration occurs. Therefore, simply controlling the opening degree of the intake throttle valve in accordance with the engine speed and the engine load (intake pressure, fuel injection amount, etc.) prevents the occurrence of exhaust smoke at the time of rapid acceleration and the problem of poor acceleration. It is not possible.

Further, if the opening degree of the intake throttle valve is controlled on the basis of the engine speed and the engine load (intake pressure, fuel injection amount) as in the apparatus disclosed in the above-mentioned publication, the intake throttle is not limited to the above problem. A problem arises in that the operation of adjusting the valve opening degree for each engine is complicated. Usually, in order to accurately control the opening degree of the intake throttle valve based on the engine speed and the engine load as described above, it is necessary to set the engine speed and the intake pressure, or each combination of the engine speed and the fuel injection amount. In advance, a numerical table (two-dimensional map) in which the opening degree of the intake throttle valve is determined is prepared in advance, and the values of the engine speed and the intake pressure (or the engine speed and the fuel injection amount) detected during operation are used for this table. It is necessary to read the intake throttle valve opening from the map. However, since the required intake throttle valve opening varies depending on the engine operating state, the combination of the engine speed and the engine load must be created for each operating state of the engine. It requires enormous man-hours to create. In addition, in order to control the opening degree of the intake throttle valve during operation, it is necessary to store the above-mentioned map in, for example, an electronic control unit. A problem arises.

In addition, as described above, the intake throttle valve opening data created in accordance with each operating state can be used in the same operating environment (for example, in the case of an automobile engine, vehicle weight, transmission gear ratio, etc.). ) Cannot be shared, and it becomes necessary to recreate a map of the intake throttle valve opening data for each vehicle type. For this reason, the man-hour for the adaptation work of the intake throttle valve control device to each engine becomes enormous, and a problem that the cost required for the work is greatly increased occurs.

[0010] In view of the above problems, one object of the present invention is to provide:
Prevents a delay in increasing the intake throttle valve opening during sudden acceleration,
It is an object of the present invention to provide an intake throttle valve control device for an internal combustion engine that does not cause problems such as exhaust smoke during rapid acceleration and deterioration of acceleration. Another object of the present invention is to provide an intake throttle valve for an internal combustion engine, which can easily perform an adaptation work of intake throttle valve control for each engine and can greatly reduce an increase in man-hours for the adaptation work. The purpose of the present invention is to provide a control device.

[0011]

Means for Solving the Problems In view of the above problems, claim 1
According to the invention described in (1), an intake throttle valve that is arranged in the intake passage of the internal combustion engine and controls the amount of intake air flowing through the intake passage, and sets a target opening degree of the intake throttle valve according to the operating state of the engine Target opening setting means, means for detecting the accelerator opening of the engine, correction means for increasing and increasing the target opening based on the detected accelerator opening, and after correcting the opening of the intake throttle valve after the correction. Driving means for controlling the target opening degree of
An intake throttle valve control device for an internal combustion engine provided with:

According to a second aspect of the present invention, in the first aspect of the invention, the target opening setting means detects an engine speed and detects an amount of fuel supplied to the engine. Means for setting the target opening based on the detected engine speed and fuel amount. Further, claim 3
In the invention described in (2), in claim 2, the target opening degree setting means sets the target opening degree based on a value obtained by multiplying the detected engine speed by a fuel amount.

According to the present invention, an intake throttle valve disposed in an intake passage of an internal combustion engine for adjusting an intake flow rate flowing through the intake passage, a means for detecting an engine speed, and an engine Means for detecting the amount of fuel supplied to, and target opening setting means for setting a target opening of the intake throttle valve based on a value obtained by multiplying the detected engine speed and the fuel amount, And a drive unit for controlling the opening degree of the intake throttle valve to the target opening degree.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of an embodiment when the present invention is applied to a diesel engine with an EGR device. In FIG. 1, 1 is a diesel engine, 2 and 3 are an intake passage and an exhaust passage of the engine 1, respectively, and 5 is an exhaust turbocharger. Further, in the present embodiment, an EGR device that recirculates a part of the exhaust gas of the engine 1 to the surge tank 2a of the intake passage 2 is provided. The EGR device includes an EGR passage 7 that connects the exhaust passage 3 and the surge tank 2a of the intake passage 2;
An EGR control valve 9 provided on the passage 7 is provided.
In FIG. 1, reference numeral 9a denotes an appropriate type of E such as a negative pressure actuator or a stepper motor for driving the EGR control valve 9.
It is a GR actuator. In the present embodiment, the control circuit 30 of the engine 1 drives the EGR actuator 9a according to the fuel injection amount of the engine 1 as described later,
The opening of the R control valve 9 is adjusted. As a result, the amount of recirculated exhaust gas (hereinafter referred to as “EGR gas”) that returns from the exhaust passage 3 of the engine to the intake passage 2 through the EGR passage 7 is controlled. Further, in the present embodiment, the EGR is performed by restricting the intake passage 2 at the upstream of the surge tank 2a of the intake passage 2 at the time of performing the EGR, reducing the flow rate of fresh air passing through the intake passage 2 and reducing the pressure of the surge tank 2a. An intake throttle valve 6 for increasing the gas amount is provided. The intake throttle valve 6
For example, the valve is a butterfly valve having a small intake resistance when fully opened, and takes an opening degree according to a drive signal from the ECU 30 described later. In FIG. 1, reference numeral 6a denotes an appropriate type of actuator such as a negative pressure actuator or a stepper motor for driving the intake throttle valve 6 in response to a drive signal from the ECU 30. A throttle valve opening sensor 6b for detecting the opening of the intake throttle valve 6 is provided on the drive shaft of the valve body of the intake throttle valve 6.

In FIG. 1, reference numeral 30 denotes a control circuit (ECU) of the engine 1. In the present embodiment, the ECU 30
ROM (read only memory) 32, RAM (random access memory) 33, CPU (microprocessor)
34, and an input port 35 and an output port 36 are connected to each other by a bidirectional bus 31 to constitute a known type of digital computer. The ECU 30 performs basic control such as fuel injection control of the engine 1, and in the present embodiment, EGR control for controlling the opening of the EGR control valve 9, and intake throttle valve control for controlling the opening of the intake throttle valve 6. Is performed.

For these controls, a voltage signal corresponding to the intake pressure PM (absolute pressure) is supplied to the input port 35 of the ECU 30 from the intake pressure sensor 11 provided in the surge tank 2a in the intake passage, and an accelerator pedal ( (Not shown) from the accelerator opening sensor 15
A voltage signal corresponding to (a driver's accelerator pedal depression amount) is supplied to a cooling water temperature sensor 1 provided in a cooling water jacket (not shown) of a cylinder block of the engine 1.
4, a voltage signal corresponding to the engine coolant temperature THW,
From the throttle valve opening sensor 6b described above, the intake throttle valve 6 opening TH
Voltage signals corresponding to the ETA are input via the AD converter 21 with a built-in multiplexer. The analog voltage signal from each sensor is input as a digital signal by an AD conversion routine executed at regular intervals by the ECU 30 and stored in the RAM 33 of the ECU 30. In addition to the above, a pulse signal representing the rotational speed NE of the engine 1 is input to the input port 35 from the rotational speed sensor 13 disposed on the crankshaft (not shown) of the engine 1. The CPU 34 calculates the engine rotational speed NE from the rotational frequency pulse frequency input at regular intervals, and calculates R
Store it in AM33. That is, the data of the intake pressure PM, the accelerator opening ACCP, the engine coolant temperature THW, the opening of the intake throttle valve 6 THETA, and the engine speed NE are updated at regular intervals, and the RAM 33 always stores the latest data. Is stored.

An output port 36 of the ECU 30 is connected to a fuel injection valve (not shown) of each cylinder of the engine 1 via an injection valve drive circuit 23a to control the fuel injection amount to the engine and to control the EGR. EGR is connected to the actuator 9a of the control valve 9 and the actuator 6a of the intake throttle valve 6 via drive circuits 23b and 23c, respectively.
The opening degree of the control valve 9 and the intake throttle valve 6 is controlled.

In the present embodiment, the fuel injection amount Qf _(fin) of the engine 1 is determined by the engine speed NE and the accelerator opening AC
It is set as follows according to the fuel injection amount target value Qf _(gov) determined by the CP and the exhaust smoke limit Qf _(ful) . That is, the ECU 30 calculates the fuel injection amount target value Qf _(gov) using the latest data of the engine speed NE and the accelerator opening ACCP stored in the RAM 33 for each rotation of the engine, and then calculates the calculated target value. Q
f _(gov) is compared with a smoke limit Qf _(ful) for preventing generation of exhaust smoke. And the target value Qf
_{When (gov)} is equal to or _smaller than the smoke limit value Qf _(ful) , the fuel injection amount Qf _(fin) is set to the target value Qf _(gov) ,
Qf _(fin) is output to the drive circuit 23a. This allows
From a fuel injection valve (not shown) of each cylinder, an amount of fuel corresponding to a target value Qf _(gov) is injected into the cylinder for each revolution of the engine. If the target fuel injection amount Qf _(gov) exceeds the smoke limit Qf _(ful) , the ECU 30
Sets the fuel injection amount Qf _(fin) to the smoke limit Qf
_(ful) and output to the fuel injection valve drive circuit 23a. As a result, the fuel injection amount of the engine 1 becomes the maximum injection amount (smoke limit) Qf at which exhaust smoke is not generated.
_(ful) .

FIG. 2 is a diagram showing the relationship between the target fuel injection amount Qf _(gov) , the accelerator opening ACCP, and the engine speed NE. The vertical axis in FIG. 2 represents the target fuel injection amount Qf _(gov) ,
The horizontal axis represents the engine speed NE, and each curve in the figure represents the target fuel injection amount Qf when the accelerator opening ACCP is constant.
_(gov) . As shown in FIG. 2, if the engine speed NE is the same, the target fuel injection amount Qf _(gov) increases as the accelerator opening ACCP increases, and if the accelerator opening ACCP is the same, the engine fuel speed Qf _(gov) increases. The value is set to a larger value as the NE is lower. Each Qf in Figure 2 _(gov)
Is stored in the ROM 32 of the ECU 30 in advance in the form of a numerical map using NE and ACCP as parameters, and the ECU 30 calculates the numerical value based on the detected values of the engine speed NE and the accelerator opening ACCP. The value of the target fuel injection amount Qf _(gov) is set from the map.

On the other hand, the value of the smoke limit Qf _(ful) is determined by the amount of fresh air flowing into the engine (ie, the amount of oxygen flowing into the engine). The amount of fresh air flowing into the engine has a one-to-one relationship with the intake pressure PM and the engine speed NE. Therefore, in this embodiment, the intake air pressure PM and the engine speed NE are changed in advance to measure the fresh air inflow amount, and the smoke limit Qf for each new air inflow amount is measured.
_(ful) and the smoke limit Qf
The value of _(ful) is stored in the ROM 32 of the ECU 30 in the form of a two-dimensional map using the intake pressure PM and the engine speed NE. The ECU 30 calculates the value of the smoke limit Qf _(ful) from the numerical table at regular intervals based on the latest data of the detected intake pressure PM and the engine speed NE, and calculates the target fuel injection amount Qf _(gov) . The final fuel injection amount Qf _{(fin )} is set by comparing with the value.

In this embodiment, the opening degree of the EGR valve 9 is
EV is the final fuel injection amount Qf calculated as described above._(fin)
And smoke limit Qf_(ful)R = Qf_(fin)/
Qf _(ful)Using the values shown in FIG.
Is determined. That is, the R of the EGR valve opening EV is small.
Region (that is, the actual fuel injection amount Qf)_(fin)Is small
Area where there is room for the limit, that is, excess air ratio
In the region where λ is large), the opening is maintained at a substantially constant large opening ratio.
A relatively large amount of EGR gas is recirculated. Also, the value of R increases
When large (Qf_(fin)Qf_(ful)Little room for
(Ie, when the excess air ratio λ decreases)
EV sharply decreases, and R = R₀(However, R₀<1.0)
EV = 0. That is, the actual fuel injection amount Qf
_(fin)Is smoke limit Qf_(ful)As you approach
The recirculation amount of EGR gas is rapidly reduced, and the engine intake air
The amount of fresh air in the air increases rapidly. Also, R ≧ R₀
, The EGR valve 9 is fully closed and the EGR gas is recirculated.
Is stopped. As a result, the fuel near the smoke limit
In the fuel injection amount region, the decrease in fresh air inflow due to EGR supply
To prevent fuel injection from being limited by smoke limits.
And can completely prevent the generation of smoke
You.

Next, control of the opening degree of the intake throttle valve 6 according to the present embodiment will be described. As described above, the throttle valve 6 an intake, and makes it possible to reduce the NO _X generation amount of the engine by limiting the flow of fresh air to the engine performs a large amount of EGR. However, on the other hand, unless the opening degree of the intake throttle valve 6 is properly set in accordance with each operating state of the engine, a decrease in engine output due to insufficient fresh air flow, an EGR
There is a possibility that problems such as deterioration of the exhaust properties due to the shortage of the amount may occur. For this reason, as described above, conventionally, control is performed based on a two-dimensional map using the engine speed NE and the intake pressure PM or the engine speed NE and the fuel injection amount Qf ₍ fin _), and the control is optimized for each operation state. Intake throttle valve opening THETA
It is done to get. However, in this case, even if the engine speed NE is constant, the intake pressure PM and the fuel injection amount Qf _{(fin )} greatly change depending on the operating state of the engine (for example, road surface conditions, transmission shift position, etc.). Accordingly, the required intake throttle valve opening THETA (that is, the required fresh air flow rate) also greatly changes. For this reason, the THETA map is created based on the results of actual measurement of the combination of the engine speed NE and the intake pressure PM (or the fuel injection amount Qf _(fin) ) in all engine operating states. Need arises. Actually, the above THETA
In the map, the optimum THETA is obtained by actual measurement only for NE and PM (or Qf _(fin) ) in a typical operating state of the engine, and the THETA in other operating states is obtained.
Is determined by interpolation calculation of the map, but the man-hour of the adaptation work for creating the THETA map for one engine is extremely enormous. Further, since this map is different for each engine use environment (for example, vehicle weight, transmission gear ratio, etc.), even if the engine is the same, if the vehicle type is different, the map cannot be shared. It becomes necessary to repeat the adaptation work.

However, the fresh air flow required by the engine is actually proportional to the engine output (KW) required by the driver. That is, if the engine output is large, the required fresh air flow rate is correspondingly large, and the intake throttle valve 6
It becomes necessary to set the opening THETA to be large, and conversely, if the engine output is small, the opening THETA of the intake throttle valve 6 can be set small accordingly. That is,
There is a correlation between the engine output and the optimum throttle valve opening THETA. Therefore, in practice, the intake throttle valve 6 is controlled for all combinations of the engine speed NE and the intake pressure PM (or the fuel injection amount Qf _{(fin )} ) in each operation state as in the prior art.
Need not be set, and it is possible to set the optimum throttle valve opening THETA using only the engine output as a parameter. Therefore, in the present embodiment, focusing on this point, the opening THETA of the intake throttle valve 6 is set using only the engine output as a parameter.

The engine output (KW) is determined by the engine speed NE (RPM) and the engine output torque (N ·
m). On the other hand, the engine output torque is proportional to the amount of fuel supplied to the engine per unit time, that is, the fuel injection amount Qf _(fin) . Therefore, in the present embodiment, the product NEQFIN of the engine speed NE and the fuel injection amount Qf _(fin) is used as a parameter representing the engine output.
The opening of the intake throttle valve 6 is set using (NEQFIN = NE × Qf _(fin) ).

FIG. 4 is a diagram showing the relationship between the intake throttle valve opening THETA and NEQFIN in this embodiment.
The vertical axis in FIG. 4 indicates the opening degree parameter LT (LT = 10
0% -THETA) is used as a parameter representing the throttle valve opening. That is, in the present embodiment, the larger the value of the opening parameter LT, the smaller the intake throttle valve opening THETA becomes. The intake throttle valve 6 is fully closed (THETA = 0) when LT = 100%, and the intake throttle valve 6 is intake when LT = 0. The throttle valve 6 corresponds to a fully open state (THETA = 100%).

As shown in FIG. 4, in this embodiment, the NEQ
When the FIN (engine output) is small, that is, when the required amount of fresh air is small, the opening degree of the intake throttle valve is set small (that is, LT is set large) and the fresh air flow rate is reduced to reduce the EGR gas. The amount is increasing. Further, the opening degree of the intake throttle valve is increased as the engine output (NEQFIN) is increased (LT is decreased), and the required fresh air amount flowing into the engine is increased according to the engine output.

As can be seen from FIG. 4, in the present embodiment, the opening degree THETA of the intake throttle valve 6 is expressed using only the product NEQFIN of the engine speed NE and the fuel injection amount Qf _(fin). Throttle valve opening T in the state
HETA can be determined only by actually measuring the engine output (NEQFIN) alone, and the engine speed NE and the intake pressure PM (or the fuel injection amount Q
It is not necessary to perform actual measurement for each combination of the two parameters f _(fin) ). That is, conventionally, the THETA is set by actual measurement for each of a plurality of combinations of the rotational speed NE and the intake pressure PM even in the operating state where the engine output is the same, but in the present embodiment, one THETA is set for each engine output.
Setting a value of is sufficient. For this reason, the intake throttle valve opening T
The work of adapting HETA to real agencies is greatly simplified.

Further, if the engine is the same, the required fresh air flow at the same engine output is the same, so that the engine is the same even when the engine operating environment such as the transmission gear ratio and the vehicle weight is different. If so, the same map (FIG. 4) can be applied to other vehicle types. For this reason, according to the present embodiment, it is not necessary to repeat the work of adjusting the opening degree of the intake throttle valve for each use environment (vehicle type) of the engine, and the work of adjusting the opening degree of the intake throttle valve for each engine is greatly simplified. Thus, the number of man-hours can be significantly reduced as compared with the related art.

Next, the control of the opening degree of the intake throttle valve during acceleration according to the present embodiment will be described. As described above, in this embodiment, the opening degree THETA of the intake throttle valve 6 is set in accordance with the product NEQFIN of the engine speed NE and the fuel injection amount Qf _(fin) , but as described above, the engine speed NE is It rises relatively slowly even when the engine suddenly accelerates. Also,
Since the fuel injection amount Qf _(fin) is limited by the smoke limit Qf _(ful) , it does not increase sharply even during rapid acceleration.
Therefore, even when the intake throttle valve 6 opening THETA is set based on the product NEQFIN of the engine speed NE and the fuel injection amount Qf _(fin) as in the present embodiment, the value of NEQFIN is It does not increase abruptly and causes problems such as poor acceleration as in the prior art.

Therefore, in the present embodiment, when the engine is accelerated, a problem such as poor acceleration is caused by increasing and correcting the throttle valve opening THETA set based on FIG. 4 by an amount corresponding to the accelerator opening ACCP. Preventing.
THET by an amount corresponding to the magnitude of accelerator opening ACCP
A is increased and corrected for the following reason. That is, the accelerator opening ACCP is proportional to the accelerator pedal depression amount of the vehicle driver. On the other hand, the driver depresses the accelerator pedal greatly when rapid acceleration is required, and depresses the accelerator pedal slightly when slow acceleration is required. Therefore, the magnitude of the accelerator opening ACCP during acceleration can be used as a parameter indicating the degree of acceleration. On the other hand, when rapid acceleration is required, it is necessary to increase the fresh air flow as quickly as possible.
It is necessary to set a large increase correction amount of the opening degree of the intake throttle valve 6 and open the throttle valve greatly during acceleration. However, if the opening degree of the intake throttle valve 6 is increased, the EGR amount is reduced accordingly. Therefore, when it is not necessary to rapidly increase the fresh air flow rate, for example, in the case of gentle acceleration, the intake throttle valve 6 (6) It is necessary to minimize the amount of correction for increasing the opening as much as possible to prevent deterioration of the exhaust properties due to a decrease in the EGR amount. Therefore, in the present embodiment, the accelerator opening ACCP is used as a parameter indicating the degree of the driver's acceleration request, and ACC
The above problem is solved by increasing and correcting the intake throttle valve opening THETA by an amount corresponding to the magnitude of P. That is, according to the present embodiment, when the driver requests the rapid acceleration and depresses the accelerator pedal greatly, the opening THETA of the intake throttle valve is corrected to increase by a large amount, and the fresh air flow rate increases rapidly. I do. For this reason, oxygen is supplied to the engine in such an amount that the amount of fuel rapidly increased due to the increase in the accelerator opening can be burned without generating smoke, and the engine speed rapidly increases. Therefore, rapid acceleration according to the driver's request can be obtained, and poor acceleration does not occur.

When the driver demands slow acceleration and depresses the accelerator pedal slightly, the throttle valve opening THE
TA is increased and corrected by a small amount, the fresh air flow rate is gradually increased, and slow acceleration according to the driver's request can be obtained. Further, in this case, since the EGR gas amount does not significantly decrease, deterioration of the engine exhaust properties during slow acceleration is prevented.

FIG. 5 is a flowchart showing the control of the opening degree of the intake throttle valve 6 in the above-described embodiment. This routine is executed by the ECU 30 at regular intervals (for example, 10 msec).
(At intervals). In FIG. 5, step 5
Reference numerals 01, 503, and 507 denote steps for determining whether or not a condition for permitting execution of intake throttle valve opening control is satisfied.
That is, in step 501, reads the latest coolant temperature data THW stored in RAM 33, THW whether is higher than the predetermined EGR exemplary temperature THW ₀ is determined. In the present embodiment, the cooling water temperature THW is a predetermined EGR execution temperature THW ₀ (in the present embodiment,
If THW is equal to or less than 30 ° C., for example, EG
Since R is not performed, in step 501, THW ≦ THW
If it is ₀ , the routine proceeds to step 505, where the intake throttle valve opening parameter set value (target opening) LT is set to 0.
And the process proceeds to step 519 described later. That is, when the EGR is not performed, it is not necessary to reduce the inflowing fresh air amount with the intake throttle valve, so the throttle valve opening parameter set value LT is set to 0, and the throttle valve 6 is fully opened.

When the cooling water temperature THW is THW₀When
The reason for not performing EGR is that the engine temperature is low
If EGR is performed in a state where combustion of
This is because there is a possibility of becoming unstable. Step 50
THW> THW at 1₀If so, step 50
Proceed to Step 3 and the latest accelerator opening stored in the RAM 33
The data ACCP is read, and this ACCP has a predetermined value AC.
CP₀Is determined, ACCP> ACC
P ₀If so, the routine proceeds to step 505, where the intake throttle
Set valve 6 to full open (LT = 0). Where ACCP
₀Is equivalent to high engine output (for example, about 80% load)
Accelerator opening. That is, in the present embodiment,
In the area where engine output is required, the intake throttle valve 6 opening
Is set to fully open to prevent output drop.
You.

If it is determined in step 503 that ACCP ≦ ACCP ₀ , it is next determined in step 507 whether or not the engine is currently performing idle operation, that is, whether or not ACCP is equal to or less than a value ACCP _idl corresponding to idle operation. And
When idling (ACCP ≦ ACC)
(P _idl ), the process proceeds to step 509, where the value of the set value LT is set to 100%, and then proceeds to step 519. That is, during idling operation of the engine fuel injection amount is extremely small, since the high operating with excess air ratio, of the NO _X at idle by refluxing a large amount of EGR gas throttle valve 6 intake in the fully closed to the engine Reduce the amount generated.

On the other hand, if it is determined in step 503 that the engine is not currently idling, steps 511 and 5
In step 13, an opening degree set value LT of the intake throttle valve 6 is calculated. That is, in step 511, the latest rotational speed data NE and the fuel injection amount Qf _(fin) are read from the RAM 33, and NE
The product of the rotational speed NE and the fuel injection amount Qf _(fin) is calculated according to QFIN = NE × Qf _(fin) , and then step 513 is performed.
Then, the opening set value LT is determined from the relationship shown in FIG. 4 using the calculated value of NEQFIN. Note that the LT value in FIG. 4 is expressed in the form of a one-dimensional numerical map using NEQFIN.
It is stored in the ROM 32 of the CU 30 in advance.

After setting the intake throttle valve opening set value LT as described above, in steps 515 and 517, the throttle valve set opening (target opening) LT during acceleration is corrected. That is, in step 515, the accelerator opening ACCP at the time of executing the current routine and the accelerator opening ACCP at the time of executing the previous routine are determined.
The difference is whether larger than the predetermined value A ₀ of the _i-1, determines the current engine whether or not the acceleration, i.e. whether or not it is necessary to increase the correction of the intake throttle valve opening. AC at step 515
If CP-ACCP _i-1 > A ₀ , it is determined that the engine is currently accelerating.
The set value LT is reduced by an amount f _(ACCP) determined from the current accelerator opening ACCP, that is, the opening of the intake throttle valve 6 is reduced by f.
_{(ACCP) is} increased and the process proceeds to step 519. Here, the increase correction amount f _(ACCP) of the intake throttle valve opening is, for example, an amount proportional to the accelerator opening ACCP, and in the present embodiment, f _(ACCP) = ACCP × １ ／.

At step 515, ACCP-AC
If CP _i−1 ≦ A ₀ , the engine is currently in steady-state operation, and it is not necessary to correct the increase in the opening of the intake throttle valve 6. Therefore, the value of the target opening LT calculated in step 513 is corrected. The process directly proceeds to step 519 without any processing. In step 519, after updating the value of ACCP _i−1 , the process proceeds to step 521, where the actual intake throttle valve opening THETA corresponds to the opening parameter LT set in any of steps 505, 509, 513, or 517. Value (THE
The actuator 6a is feedback-controlled so that TA = 100% −LT). This feedback control is, for example, a known PID (proportional, integral, differential) control based on a deviation between the actual throttle valve opening and the target opening, and thus details of the control are omitted.

According to the above routine, when the engine is accelerated, the intake throttle valve opening is increased and corrected in accordance with the accelerator opening ACCP, so that a sufficient amount of fresh air is supplied to the engine, and exhaust smoke is generated and acceleration is poor. Is prevented from occurring. In the above-described embodiment, the increase correction amount f _(ACCP) of the intake throttle valve opening during acceleration is set as an amount proportional to the accelerator opening ACCP (for example, f _(ACCP) = ACCP × １ ／). However, if the value of f _(ACCP) is set to increase as the accelerator opening increases, setting other than the above is also possible. Also, by changing the setting of f _(ACCP) , desired EGR characteristics and acceleration characteristics can be set. For example, FIG. 6 is a diagram illustrating another setting of the increase correction amount f _(ACCP) . In the setting of FIG. 6, f _(ACCP) is the accelerator opening ACC
It is set so that it takes a small value in a region where P is small, increases relatively sharply as ACCP increases, and maintains a large value in a region where ACCP is large. By setting the increase correction amount f _(ACCP) in this manner, at the time of gentle acceleration (Small ACCP) during light load operation, maintaining the EGR gas amount has priority over acceleration, and during high load operation or abrupt acceleration. At the time of acceleration, the opening degree characteristic of the intake throttle valve that gives priority to acceleration over maintenance of the EGR gas amount can be obtained.

[0039]

According to the first to third aspects of the present invention,
By appropriately controlling the opening degree of the intake throttle valve during acceleration of the engine, it is possible to obtain an excellent acceleration performance of the engine while preventing deterioration of the exhaust properties due to an excessive decrease in the amount of EGR gas. According to the fourth aspect of the present invention, the work of adapting the opening degree of the intake throttle valve to each engine is greatly simplified, and the number of steps of the adaptation work can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment when the present invention is applied to an automobile diesel engine.

FIG. 2 is a diagram illustrating a method for setting a fuel injection amount in the embodiment of FIG.

FIG. 3 is a diagram illustrating a method for setting an EGR valve opening in the embodiment of FIG. 1;

FIG. 4 is a diagram showing an example of setting of an intake throttle valve opening in the embodiment of FIG. 1;

FIG. 5 is a flowchart illustrating a setting operation of an intake throttle valve opening in the embodiment of FIG. 1;

FIG. 6 is a diagram showing an example of setting an increase correction amount of an intake throttle valve opening in the routine of FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 diesel engine 2 intake passage 3 exhaust passage 6 intake throttle valve 9 EGR valve 30 control circuit (ECU)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02D 45/00364 F02D 45 / 00364N

Claims (4)

[Claims] 1. An intake throttle valve disposed in an intake passage of an internal combustion engine for controlling an intake flow rate flowing through the intake passage, and a target opening for setting a target opening of the intake throttle valve in accordance with an operation state of the engine. Setting means; means for detecting an accelerator opening of the engine; correcting means for increasing and correcting the target opening based on the detected accelerator opening; and a target opening after the correction of the opening of the intake throttle valve. And a drive unit for controlling the intake throttle valve of the internal combustion engine. 2. The target opening setting means includes a means for detecting an engine speed and a means for detecting an amount of fuel supplied to the engine, and based on the detected engine speed and the fuel amount. The intake throttle valve control device according to claim 1, wherein the target opening is set. 3. The intake throttle valve control device according to claim 2, wherein the target opening degree setting means sets the target opening degree based on a value obtained by multiplying the detected engine speed by a fuel amount. 4. An intake throttle valve arranged in an intake passage of an internal combustion engine for adjusting an intake flow rate flowing through the intake passage, means for detecting an engine speed, and means for detecting an amount of fuel supplied to the engine. Target opening setting means for setting a target opening of the intake throttle valve based on a value obtained by multiplying the detected engine speed and the fuel amount; and setting the intake throttle valve opening to the target opening. And a drive means for controlling the throttle valve of the internal combustion engine.