JPH06241079A - Throttle valve control device of engine - Google Patents

Abstract

PURPOSE:To provide a means for a lean burn engine equipped with an electric throttle valve, whereby the accuracy of throttle valve control can be enhanced and torque shock at the time of switching the air-fuel ratio can be precluded. CONSTITUTION:A lean burn engine CE equipped with an electric throttle valve 25 includes a control unit C, which determines the target illustrated mean effective pressure on the bias of the accel. opening and engine speed, determines the target charging efficiency on the basis of the target illustrated means effective pressure and the target air-fuel ratio, and determines the target throttle valve opening on the basis of the target charging efficiency. Therein the target illustrated mean effective pressure, target air-fuel ratio, and target throttle valve opening are determined through searching over a map, and the control responsiveness is enhanced. The target charging efficiency is precisely obtained from an arithmetic expression including the fuel consumption enhancement factor, and the output torque is controlled with high precision, and torque shock at the time of switching the air-fuel ratio can be precluded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine throttle valve control device.

[0002]

2. Description of the Related Art Generally, an automobile is provided with a throttle valve (mechanical throttle valve) that works in conjunction with an accelerator pedal through a mechanical link mechanism, and opens and closes the throttle valve according to the amount of depression of the accelerator pedal by the driver. It is often used to control engine output (engine load). However, in an automobile in which the engine output is controlled by such a mechanical throttle valve, it is difficult to obtain the optimum engine output according to the operating state of the automobile.

Therefore, in recent years, a throttle valve (electric throttle valve) which is opened and closed by an electric actuator such as a servomotor according to a signal from a control unit.
While operating the control unit
A target driving force is set using a map according to (for example, accelerator opening, engine speed, vehicle speed, presence / absence of braking, etc.), and a target throttle opening is obtained so that the target driving force can be obtained. A vehicle has been proposed in which the electric throttle valve is opened and closed to control the engine output so as to follow the target throttle opening (see, for example, Japanese Patent Laid-Open No. 4-63945).

On the other hand, in an ordinary spark ignition engine for automobiles, a mixture of fuel (eg, gasoline) and air is compressed by a piston in a combustion chamber and then ignited and burned by a spark plug. It is like this. In such an engine, basically, the air-fuel ratio of the air-fuel mixture (air / fuel ratio A / F) can be arbitrarily set within the combustible range.

When the air-fuel ratio of the air-fuel mixture is changed, when the air-fuel mixture is rich, the engine output is high but the fuel efficiency (fuel consumption rate) is low. On the other hand, when the air-fuel mixture is lean, the engine output is low but the fuel efficiency is high. Therefore, in recent years, in an operating region where high output is required, the air-fuel ratio is set to a predetermined rich region (for example, the theoretical air-fuel ratio A /
On the other hand, the so-called lean burn engine is often used in which the air-fuel ratio is set to the lean range to improve the fuel efficiency in the operating range where high output is not required.

Further, in general, in an engine, the CO and HC generation rates are 2 (A / F is 2 when the air-fuel mixture becomes lean.
Since it becomes lower (as it approaches 0), the lean-burn engine also improves the emission performance from this viewpoint. However, unlike the CO or HC, the NOx generation rate is slightly leaner than the stoichiometric air-fuel ratio.
It has a characteristic that it has a peak at around 16 (A / F).

Therefore, for example, basically, while the rich region is set to the theoretical air-fuel ratio (A / F = 14.7), the lean region is leaner than the air-fuel ratio where the NOx generation rate reaches the peak.
(For example, in a lean burn engine set to A / F = 19 to 24), if the air-fuel ratio is changed continuously (gradually) at the time of switching between rich and lean, the NOx generation rate peaks at each switching. Therefore, there is a problem in that the emission performance for NOx is deteriorated because it goes through the air-fuel ratio range.

Therefore, generally, in a lean burn engine, the rich region is set near the stoichiometric air-fuel ratio, while the lean region is leaner than the air-fuel ratio region where the NOx generation rate reaches a peak (for example, A / F = 19-). 24), the rich / lean switching is performed all at once (discontinuously) (see, for example, JP-A-60-13953).

[0009]

However, if the air-fuel ratio is switched at once in this way, the output characteristics of the engine differ considerably between the rich range and the lean range.
There is a problem that torque shock occurs when switching.

Further, in an automobile equipped with a conventional electric throttle valve control device as disclosed in, for example, Japanese Patent Laid-Open No. 4-63945, if the air-fuel ratio is switched according to the driving state, it is possible to find a rich condition. There is a problem that the control unit becomes large or complicated because it requires two types of maps for leaning. Further, in the conventional throttle valve control using such a map, it is difficult to accurately obtain the target throttle opening.

The present invention has been made in order to solve the above-mentioned conventional problems, and is provided with an electric throttle valve that is opened / closed according to an operating state, and the air-fuel ratio is rich / lean according to the operating state. It is an object of the present invention to provide a means capable of increasing the accuracy of throttle valve control for an engine which is switched at once and preventing the occurrence of torque shock when switching the air-fuel ratio.

[0012]

In order to achieve the above object, as shown in the configuration of FIG. 1, a first invention is to open a target throttle valve opening for setting a target throttle valve opening according to an operating state of an engine. Degree setting means a and the throttle valve b so that the throttle valve opening follows the target throttle valve opening.
In the throttle valve control device of the engine provided with the throttle valve control means c for controlling, the target indicated mean effective pressure is represented by the target indicated mean effective pressure map with respect to the accelerator opening and the engine speed. By the target indicated average effective pressure setting means d for obtaining the target indicated average effective pressure corresponding to the accelerator opening and the engine speed, and the calculation formula expressing the target charging efficiency as a function of the target indicated average effective pressure and the target air-fuel ratio, Target charging efficiency calculating means e for calculating the target charging efficiency corresponding to the target indicated mean effective pressure and the target air-fuel ratio is provided, and the target throttle valve opening setting means a is used to target the target throttle valve opening. Set the target throttle valve opening corresponding to the target charging efficiency every moment by the target throttle valve opening map that shows the efficiency. A throttle valve control device for an engine is provided.

In a second aspect of the present invention, in the engine throttle valve control device according to the first aspect, the arithmetic expression used by the target charging efficiency calculating means e to calculate the target charging efficiency is (target charging efficiency) = ( Constant) × (Target indicated mean effective pressure) ×
A throttle valve control device for an engine, characterized in that (target air-fuel ratio) × (fuel efficiency improvement coefficient showing characteristics of fuel efficiency with respect to target air-fuel ratio).

According to a third aspect of the present invention, in the engine throttle valve control apparatus according to the second aspect of the present invention, the fuel consumption rate improvement coefficient is a function of the target air-fuel ratio and the engine temperature. Provide a control device.

[0015]

EXAMPLES Examples of the present invention will be specifically described below.
As shown in FIG. 2, each cylinder (1
(Only one is shown), basically, when the first and second intake valves 1 and 2 are opened, the first and second independent intake passages are connected via the first and second intake ports 3 and 4. The air-fuel mixture is sucked into the combustion chamber 7 from 5, 6 and is compressed by the piston 8 to be ignited and combusted by the spark plug 9, so that the first and second exhaust valves 10, 11
When the engine is opened, the combustion gas is discharged to the first and second exhaust ports 1
The process of discharging to the first and second independent exhaust passages 14 and 15 via 2 and 13 is repeated. The engine CE is operated at a theoretical air-fuel ratio (A / F = 14.7) in an operating range where a high output is required, while it has a lean air-fuel ratio (A / F) in an operating range where a relatively high output is not required. It is a lean burn engine that is operated at = 19 to 24).

By the continuous repetition of such a process, the piston 8 reciprocates in the axial direction in the cylinder bore, and the reciprocating motion of the piston 8 is performed via the connecting rod 16, the crank pin 17, and the crank arm 18. The rotary motion is converted and transmitted to the crankshaft 19. A high voltage is applied to the spark plug 9 from the direct ignition coil 20 at a predetermined timing, and the high voltage causes a spark discharge in the electrode portion of the spark plug 9. The first and second independent exhaust passages 14 and 15 are gathered downstream in one common exhaust passage 41, and a catalytic converter 42 for purifying exhaust gas is provided in the common exhaust passage 41. Common exhaust passage 4
1, an O ₂ sensor 63 that detects the O ₂ concentration in the exhaust gas (that is, the air-fuel ratio) and first and second exhaust temperature sensors 64 and 65 that detect the exhaust gas temperature are provided in advance. In addition, a water temperature sensor 66 that detects the cooling water temperature (engine temperature) is provided in the engine body.

In order to supply air to the combustion chamber 7 of each cylinder, a single common intake passage 21 having an upstream end open to the atmosphere.
The common intake passage 21 is provided with an air cleaner 22 for removing dust in the intake air, an air flow sensor 23 for detecting the intake air amount, and a control unit C in order from the upstream side in the flow direction of the air. An electric throttle valve 25 that is opened and closed by a servo motor 24 according to the applied signal is interposed. The downstream end of the common intake passage 21 is connected to a surge tank 26 that stabilizes the flow of intake air, and the surge tank 26 is provided with the first and second independent intake passages 5 for each cylinder.
The upstream ends of 6 are connected. In addition, this intake system,
A boost sensor 61 that detects an intake negative pressure in the surge tank 26 and an intake temperature sensor 62 that detects an intake air temperature.
And a throttle valve opening sensor 67 for detecting the throttle valve opening.

The common intake passage 21 is provided with a bypass intake passage 27 that bypasses the electric throttle valve 25 and allows air to pass therethrough. In the bypass intake passage 27, the flow rate of the air flowing in the bypass intake passage 27 is provided. ISC valve 2 that controls the idle speed by adjusting
8 is installed.

A fuel injection valve 31 for injecting fuel (gasoline) into the air in the first independent intake passage 5 to form a mixture is provided for the first independent intake passage 5. The fuel injection amount of the fuel injection valve 31 is set such that the air-fuel ratio A / F of the air-fuel mixture becomes a target air-fuel ratio afw set according to the operating state (engine speed etc.) using the air-fuel ratio map (see FIG. 3). It is controlled by the control unit C so as to follow.

An on-off valve 32 is provided in the second independent intake passage 6.
The on-off valve 32 is opened and closed by an actuator 33 composed of a negative pressure responsive diaphragm device. Specifically, by the three-way valve 35,
Whether the negative pressure in the surge tank 26 or the atmospheric pressure is introduced into the pressure chamber of the actuator 33 through the negative pressure passage 34 is switched, and when the negative pressure is introduced into the pressure chamber, the actuator 33 opens and closes the valve. When the valve 32 is closed and the atmospheric pressure is introduced into the pressure chamber, the opening / closing valve 32 is opened. The on-off valve 32 is closed in a low load region or the like, at which time air is supplied to the combustion chamber 7 only from the first intake port 3, swirl is generated in the combustion chamber 7, and the air-fuel mixture is stratified in the combustion chamber 7. And the ignitability and combustibility of the air-fuel mixture are improved. The on-off valve 32 is opened in a high load region or the like, and at this time, air is supplied from both intake ports 3 and 4 into the combustion chamber 7 so that intake charging efficiency is improved.

A blow-by gas passage 37 equipped with a PCV valve 36 is provided for introducing blow-by gas generated in the engine (crank chamber) into the surge tank 26.
Is provided. Further, a fresh air introduction passage 38 for supplying a part of the air in the common intake passage 21 into the engine is provided in order to accelerate the discharge of the blow-by gas.

The fuel supply system for supplying fuel (gasoline) to the fuel injection valve 31 will be described below. In this fuel supply system, the fuel in the fuel tank 45 is the fuel filter 4
After being sucked into the fuel pump 47 through 6, the fuel pump 47 is discharged at a predetermined discharge pressure and is supplied to the fuel injection valve 31 through a fuel supply passage 48 in which a filter 49 is interposed. Excess fuel that is not injected by the fuel injection valve 31 is returned to the fuel tank 45 through a fuel return passage 51 in which a pressure regulator 52 that controls the fuel pressure is provided. In order to eliminate the influence of the intake negative pressure, the intake negative pressure in the surge tank 26 is introduced through the negative pressure introducing passage 53.

The air containing the gasoline vapor in the fuel tank 45 is released to the surge tank 26 through the in-tank air release passage 54 in order to prevent the diffusion of the gasoline vapor into the atmosphere. And
In the in-tank air release passage 54, a separator 55 for separating the gasoline mist in the released air, a two-way valve 56, and a gasoline vapor in the released air in order from the upstream side in the flow direction of the air. A canister 57 for adsorbing the toner, an orifice 58, and a duty solenoid valve 59 are interposed.

In the engine CE, by the control unit C equipped with a microcomputer, the intake air amount detected by the air flow sensor 23, the intake negative pressure detected by the boost sensor 61,
Intake air temperature detected by the intake air temperature sensor 62, O ₂
O ₂ concentration (air-fuel ratio) detected by the sensor 63,
The exhaust gas temperature detected by the second exhaust temperature sensors 64, 65, the cooling water temperature (engine temperature) detected by the water temperature sensor 66, the throttle valve opening detected by the throttle valve opening sensor 67, the rotation speed sensor ( Various controls are performed by using engine speed detected by an unillustrated), accelerator opening detected by an accelerator opening sensor (not shown), and the like as control information. However, the general control of the engine CE is not the gist of the present invention, and therefore its explanation is omitted.
Hereinafter, referring to FIG. 2 as needed according to the flowchart shown in FIG. 3, according to the gist of the present invention, air-fuel ratio control for switching the air-fuel ratio according to the operating state and throttle for controlling the throttle valve opening degree according to the operating state Only valve control will be described. The control unit C includes the "target throttle valve opening setting means", the "throttle valve control means", the "target indicated mean effective pressure setting means", and the "target charging efficiency calculation means" described in the claims. It is a comprehensive control device including.

As shown in FIG. 3, in such control, first, in step # 1, the target indicated mean effective pressure pit corresponding to the accelerator opening Ac and the engine speed Ne is found by searching the target indicated mean effective pressure map. Required (read). This target indicated mean effective pressure map is a map showing the target indicated effective pressure pit with respect to the accelerator opening Ac and the engine speed Ne, that is, the momentary operation represented by the accelerator opening Ac and the engine speed Ne. It is a map in which the target indicated mean effective pressure pit (that is, engine output torque) most suitable for the state can be read, and its characteristics are shown in the frame of step # 1.

At step # 2, the operating condition is the air-fuel ratio.
Is it in the rich zone where (A / F) should be approximately the theoretical air-fuel ratio (A / F = 14.7, that is, excess air ratio λ = 1), or is the air-fuel ratio that maximizes the NOx generation rate? Predetermined air-fuel ratio on the lean side of the range (A / F is around 16)
(For example, A / F = 19 to 24) Zone determination is performed to determine whether the vehicle is in the lean zone. As described above, both the rich zone and the lean zone are set outside the air-fuel ratio range where the NOx generation rate is the maximum, so the emission performance for NOx is enhanced.

In the present embodiment, the zone determination is made based on the target indicated mean effective pressure pit and the engine speed Ne. That is, as shown in the frame of step # 2, the predetermined high output region is generally in the rich zone where the target indicated mean effective pressure pit is high or the engine speed Ne is high.
(A / F = 1, that is, λ = 1), and the other operating region, that is, the low output region where both the target indicated mean effective pressure pit and the engine speed Ne are low, is the lean zone (A / F =
19 to 24). It should be noted that hysteresis is provided in order to prevent frequent zone switching (cycling) near the boundary between both zones. Therefore, the engine output is sufficiently increased in the high output range where the air-fuel ratio is rich, while the fuel efficiency and the emission performance are sufficiently improved in the low output range where the air-fuel ratio is lean. It should be noted that switching between rich and lean is quick
Since it is carried out (discontinuously), it does not pass through the air-fuel ratio region where the NOx generation rate becomes maximum at the time of switching, and therefore the emission performance for NOx becomes extremely good.

In step # 3, the target air-fuel ratio afw corresponding to the intake air amount Q / N and the engine speed Ne is obtained by searching the air-fuel ratio map based on the zone determination result in step # 2 (reading). ). The air-fuel ratio map is a map in which the target air-fuel ratio afw is represented with respect to the intake air amount Q / N and the engine speed Ne, that is, the operating state is represented by the intake air amount Q / N and the engine speed Ne. It is a map that makes it possible to read the target air-fuel ratio afw most suitable for
It is illustrated in the frame of 3. The air-fuel ratio control is basically performed by feedback-controlling the fuel injection amount of the fuel injection valve 31 so that the actual air-fuel ratio detected by the O ₂ sensor 63 follows the target air-fuel ratio afw. Done.

In this embodiment, when it is determined that the vehicle is in the rich zone, the target air-fuel ratio afw is set to the stoichiometric air-fuel ratio (A / F = 14.7, that is, λ = 1). It is not necessary to read the target air-fuel ratio afw from the fuel ratio map.
However, it is needless to say that the target air-fuel ratio afw may be read using the air-fuel ratio map by changing the air-fuel ratio according to the operating state even in the rich zone.

In step # 4, the target charging efficiency cet is calculated by the following equation 1 based on the target indicated mean effective pressure pit and the target air-fuel ratio afw.

[Equation 1] cet = KITPCE ・ pit ・ (afw / 14.7) ・ fipol (afw, tw) …………………… Formula 1 cet ………… Target charging efficiency KITPCE ………… Conversion coefficient (constant) ) pit ………… Target indicated mean effective pressure afw ………… Target air-fuel ratio tw …………… Engine temperature (cooling water temperature) fipol (afw, tw)… Fuel efficiency improvement coefficient In formula 1, fipol (afw , tw) is a fuel efficiency improvement coefficient showing the characteristic of the fuel efficiency with respect to the target air-fuel ratio, and is a function of the target air-fuel ratio afw and the engine temperature tw (cooling water temperature).

In general, the target charging efficiency cet is (cet = KITPC
E ・ pit ・ afw / 14.7).
However, with such a conventional calculation method, the target air-fuel ratio
When afw is lean, the target charging efficiency cet becomes excessive,
There arises a problem that the output torque of the engine becomes excessive. That is, according to the knowledge of the inventor of the present application, the fuel consumption rate (fuel consumption rate) has a characteristic that it decreases as the air-fuel ratio becomes leaner (fuel consumption improves). For example, air-fuel ratio A /
When F is 22, the fuel economy is about 13% better than when the stoichiometric air-fuel ratio (A / F = 14.7). It is considered that this is because when the air-fuel ratio is lean, the specific heat ratio (thermal efficiency) is better than when it is rich, and the throttle opening for obtaining the same torque is increased to reduce pumping loss.

Therefore, in the above conventional calculation method, the larger the target air-fuel ratio afw is (lean), the larger the target charging efficiency cet becomes than the proper value, and the generated torque becomes excessive. Further, since the thermal efficiency also depends on the engine temperature, in the present embodiment, the fuel efficiency improvement coefficient fipol (afw, tw), which is a function of the target air-fuel ratio afw and the engine temperature tw, is introduced as shown in Expression 1. Appropriate target charging efficiency ce regardless of the target air-fuel ratio afw or the engine temperature tw.
I am trying to get t. Therefore, according to the present embodiment, the accuracy of the target charging efficiency cet is significantly increased, and thus the torque control accuracy is significantly increased. It is considered impossible to obtain a highly accurate target charging efficiency cet by searching using a map.

In step # 5, the target throttle valve opening TVOt corresponding to the target charging efficiency cet and the engine speed Ne is obtained (read) by searching the target throttle valve opening map. This target throttle valve opening map maps the target throttle valve opening TVOt to the target charging efficiency cet.
And a map expressed with respect to the engine speed Ne, that is, the most suitable for the momentary operating state represented by the target charging efficiency cet and the engine speed Ne, and the actual indicated mean effective pressure (engine output torque) It is a map that makes it possible to read the target throttle valve opening such that it can surely match the target indicated mean effective pressure pit (target engine output torque).
It is illustrated in the frame of.

In step # 6, the electric throttle valve 25 is opened / closed via the servo motor 24 so as to follow the target throttle valve opening TVOt obtained in step # 5, whereby the target indicated mean effective pressure pit ( The target charging efficiency cet), that is, the target engine output torque is obtained. In this way, the optimum target engine output torque set according to the operating state of the engine CE is accurately and surely realized, so that even if the rich / lean zone switching is performed, a torque shock due to the switching occurs. do not do.

In step # 6, when the target throttle valve opening TVOt changes, the actual throttle valve opening TVO, the fuel injection amount, and the ignition timing are changed accordingly. There is a slight difference in the responsiveness of. That is, when the control output is changed in response to the control command (control output change command), the throttle valve 25 has the longest time until the engine output torque actually changes in accordance with the control output change. The fuel injection valve 31 is next longest, and the spark plug 9 is shortest.
Therefore, it is preferable to issue a control command for the throttle valve 25, the fuel injection valve 31, and the ignition plug 9 so as to minimize the time required for the torque change in consideration of the difference in responsiveness.

FIG. 4 shows the target throttle valve opening (graph G ₁ '), the actual throttle valve opening (graph G ₁ ), and the filling amount (graph) when the timing of issuing the control command is adjusted in this way. G ₂ ), fuel injection (graph G ₃ ), ignition timing (graph G ₄ ) and engine output torque (graph G ₅ ) are shown with respect to time change characteristics. Note that in the example shown in FIG. 4, the target throttle valve opening is changed at time t ₁ , and at the same time, a control command is issued to the electric throttle valve 25 (servo motor 24), and the fuel injection valve 31 is sent to the fuel injection valve 31 at time t _2. The control command is issued, and the control command is issued to the spark plug 9 at time t ₃ . As is clear from FIG. 4, the time required to change the engine output torque is extremely short.

Further, the electric throttle valve 25 is controlled by the control unit C via the servo motor 24, and
Feedback control is performed by the D operation (proportional / integral / derivative operation). In this case, as shown in FIG.
P value (graph H ₁ ) and I value (graph H ₂ )
It is preferably set according to cet. With this configuration, the torque change at the time of shifting from the region where the feedback control is not performed to the feedback control region is reduced or prevented.

As described above, according to such control, the target indicated mean effective pressure pit, the target air-fuel ratio afw, and the target throttle valve opening TVOt, which are influenced by the engine speed, respectively, are read (retrieved) by a fast-moving map. Because it is required
It is possible to respond to a relatively drastic change in the engine speed without a response delay, and control can be performed with a small response delay. Further, since the target charging efficiency cet is calculated by using an arithmetic expression in which the fuel efficiency improvement coefficient is added, a highly accurate target charging efficiency cet corresponding to the target indicated mean effective pressure pit and the target air-fuel ratio afw can be obtained. Even when the rich / lean zone switching occurs, the engine output torque can be reliably maintained at the target value, and the torque shock at the time of switching can be prevented.

[0039]

According to the first aspect of the present invention, the target indicated mean effective pressure and the target throttle valve opening TVOt, which are influenced by the engine speed, are read in a fast-moving map.
Since it is obtained by (search), it is possible to respond to a relatively severe change in the engine speed without a response delay, and it is possible to perform throttle valve control with a small response delay. Further, since the target charging efficiency is accurately calculated using the arithmetic expression, a highly accurate target charging efficiency according to the target indicated mean effective pressure and the target air-fuel ratio can be obtained, and a discontinuous change in the air-fuel ratio, for example, Even when a rich / lean zone switching occurs in the lean burn engine, the engine output torque is reliably maintained at the target value, and torque shock does not occur.

According to the second invention, basically, the same operation and effect as those of the first invention can be obtained. Furthermore, since the target charging efficiency is preferably corrected by the fuel efficiency improvement coefficient,
The accuracy of the target filling efficiency is further increased.

According to the third invention, basically, the same operation and effect as those of the second invention can be obtained. Furthermore, since the fuel efficiency improvement coefficient is a function of the target air-fuel ratio and the engine temperature, the target charging efficiency is calculated according to the change in the fuel efficiency resulting from the target air-fuel ratio or the engine temperature, and the accuracy of the target charging efficiency is improved. It is further enhanced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of first to third inventions corresponding to claims 1 to 3.

FIG. 2 is a system configuration diagram of an engine including a throttle valve control device according to the present invention.

FIG. 3 is a flowchart showing a control method of air-fuel ratio control and throttle valve control.

[Fig. 4] In throttle valve control, a throttle valve,
It is a figure which shows an example of the timing which issues a control command to a fuel injection valve and an ignition plug.

FIG. 5 is a diagram showing characteristics of feedback control P value and I value with respect to target charging efficiency in throttle valve control.

[Explanation of symbols]

 CE ... Engine C ... Control unit 9 ... Spark plug 24 ... Servo motor 25 ... Electric throttle valve 31 ... Fuel injection valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomomi Watanabe 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (3)

[Claims] 1. A target throttle valve opening setting means for setting a target throttle valve opening according to an operating state of an engine, and a throttle for controlling the throttle valve so that the throttle valve opening follows the target throttle valve opening. In the engine throttle valve control device provided with the valve control means, by the target indicated mean effective pressure map showing the target indicated mean effective pressure with respect to the accelerator opening and the engine speed,
A target indicated mean effective pressure setting means for obtaining a target indicated mean effective pressure corresponding to the momentary accelerator opening and engine speed, and a calculation formula expressing the target charging efficiency as a function of the target indicated mean effective pressure and the target air-fuel ratio. , Target charging efficiency calculating means for calculating target charging efficiency corresponding to the target indicated mean effective pressure and target air-fuel ratio, and the target throttle valve opening setting means sets the target throttle valve opening to the target charging efficiency. A throttle valve control device for an engine, wherein a target throttle valve opening map corresponding to the target charging efficiency is set every moment based on a target throttle valve opening map expressed with respect to efficiency. 2. The engine throttle valve control device according to claim 1, wherein the calculation formula used by the target charging efficiency calculation means to calculate the target charging efficiency is (target charging efficiency) = (constant) × ( An engine throttle valve control device characterized in that (target indicated mean effective pressure) × (target air-fuel ratio) × (fuel efficiency improvement coefficient showing characteristics of fuel efficiency with respect to target air-fuel ratio). 3. The engine throttle valve control device according to claim 2, wherein the fuel efficiency improvement coefficient is a function of the target air-fuel ratio and the engine temperature.