JPH05149179A - Engine control device - Google Patents

Abstract

PURPOSE:To control a fuel injection amount and an ignition timing by detecting the filling efficiency of air, with which each cylinder is filled, with high preci sion. CONSTITUTION:A reference filling efficiency Ce0 and a reference pressure difference alphaP0 in a cylinder are decided by a standardized reference value deciding means 37 based on the running state of an engine 31 and the number of revolutions of the engine. From a pressure difference alphaP in a cylinder and the reference pressure difference alphaP0 in a cylinder, a standardized pressure difference alphaP/alphaP0 in a cylinder is decided by means of a a standardizing means 38 for a pressure difference in a cylinder. From the standardized pressure difference alphaP/alphaP0 in a cylinder and the reference filling efficiency Ce0, filling efficiency Ce is computed by a filling efficiency computing means 39. The filling efficiency Ce is corrected by a filling efficiency correcting means 310 based on temperature in a cylinder. The corrected filling efficiency is averaged by a filling efficiency averaging means 317 and based on the averaged value, an air-fuel ratio and an ignition timing are controlled by means of a computing control means 312. Thus, control to a proper fuel injection amount and to the optimum ignition timing is practicable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, when performing fuel injection and ignition timing control of an engine, calculates the fuel injection quantity and ignition timing from the pressure in the combustion chamber (hereinafter referred to as cylinder pressure), and calculates the air-fuel ratio, Also, the present invention relates to an engine control device that calculates the charging efficiency of the engine required when controlling the ignition timing.

[0002]

2. Description of the Related Art There are various conventional engine control devices using a cylinder pressure sensor.
A conventional example disclosed in JP-A-1-253543 will be described as an example.

FIG. 22 is a block diagram showing a conventional engine control device. In FIG. 22, reference numeral 61 denotes an engine body, in which a cylinder head 61a is provided with an in-cylinder pressure sensor 62 and an in-cylinder temperature sensor 63 in each cylinder. It is exposed in the combustion chamber of the cylinder.

An injector 64 is installed at an intake port 61b communicating with each cylinder of the engine body 61, and the intake port 61b is communicated with a throttle chamber 66 via an intake manifold 65.

A throttle valve 613 is arranged in the throttle chamber 66, and an upstream side of the throttle chamber 66 is connected to an air cleaner 68 via an intake pipe 67. Further, a distributor 691 connected to a camshaft (not shown) of the engine body 61 is provided with a timing sensor 610 for detecting a preset crank angle of each cylinder.

On the other hand, an air-fuel ratio sensor 611 is installed at the junction of the exhaust manifold 69 communicating with the exhaust port 61c of the engine body 61. 612 is a catalytic converter.

A control unit (hereinafter referred to as an ECU) 614 is composed of a microcomputer including, for example, a CPU, a RAM, a ROM, an input interface, etc., and the cylinder pressure sensor 6 is provided on the input side of the ECU 614.
2, the in-cylinder temperature sensor 63, the timing sensor 610, and the air-fuel ratio sensor 611 are connected. Furthermore, this EC
The injector 64 is connected to the output side of U614 via a drive circuit 616.

A spark plug 615 is installed on the cylinder head 61a. The ignition plug 61 is connected to the output side of the ECU 614 via a drive circuit 617.
5 is connected. The calculation of the intake air amount Ga for each cylinder in the ECU 614 is performed, for example, by the following equation (1). Ga = (P × V) / (R × T) (1) Here, P is a predetermined crank angle (for example, BTDC 90 ° CA) set in advance in the compression stroke of each cylinder based on the timing sensor 610. Note that, hereinafter, the crank angle is referred to as ° CA) and is the in-cylinder pressure measured by the ECU 614. V is the volume of the combustion chamber at this predetermined crank angle. R is the gas constant during the compression stroke, T
Is the in-cylinder gas temperature measured by the in-cylinder temperature sensor 63.

On the other hand, according to Japanese Patent Laid-Open No. 59-214433, as shown in FIG. 23, when the pressure difference in cylinder between the compression bottom dead center (BDC) and 40 CA before the compression top dead center is ΔP,
As shown in FIG. 24, the amount Ga of air charged into the engine and the in-cylinder pressure difference ΔP have a linear relationship. Based on this relationship, the intake air amount is calculated from the in-cylinder pressure difference ΔP at two predetermined crank angles during the compression stroke.

Further, according to Japanese Patent Laid-Open No. 60-47836, the fuel injection time as shown in FIG. 25 is stored in advance in the ROM of the ECU using the in-cylinder pressure difference ΔP and the engine speed N as parameters. There is also a method of obtaining the fuel injection time by using the two-dimensional map table of. The ECU 614 executes such calculation of the amount of air Ga filled in the engine. Based on the air amount calculation result, the fuel pulse width Ti is calculated by the following equation (2). Ti = K × Ga × K _FB (2) Here, K is an air-fuel ratio constant and K _FB is an air-fuel ratio feedback correction amount. Then, a signal is sent from the ECU 614 to the drive circuit 616 based on the result of the fuel injection pulse width calculation, the injector 64 is driven, and the air-fuel ratio control is performed.

According to Japanese Patent Laid-Open No. 59-103965, the absolute value of the in-cylinder pressure as shown in FIG.
There is also a method of obtaining the ignition timing by a two-dimensional map table of the ignition timing which is determined in advance for each operating condition measured by the CA and determined by the in-cylinder pressure value and the engine speed. Such an ignition timing is determined by the ECU 614, a signal is sent to the drive circuit 617 to drive the spark plug 615,
I was controlling the ignition timing.

[0012]

The conventional engine control device is constructed as described above, and the in-cylinder pressure sensor 62 is used.
The in-cylinder pressure P measured at a predetermined crank angle and the charging efficiency C detected by the in-cylinder pressure difference ΔP
In the case of e, the measurement accuracy is deteriorated due to a measurement error due to noise when measuring the in-cylinder pressure and a measurement error due to intake pulsation, and the filling air amount detection accuracy is reduced. It had the drawback of decreasing.

Further, the relationship between the in-cylinder pressure difference ΔP and the charging efficiency Ce changes with the engine speed due to a dynamic effect such as inertial supercharging of the intake system which changes depending on the engine speed, so that from the in-cylinder pressure difference ΔP. There was a problem that the detection error of the charging efficiency Ce of 1 changes with the engine speed.

Further, when the operating condition of the engine changes, the properly normalized in-cylinder pressure difference and the reference charging efficiency change,
There is a problem that the detection error of the filling efficiency Ce from the in-cylinder pressure difference ΔP changes.

The invention set forth in claim 1 has been made to solve the above problems, and affects the measurement error when the pressure in the combustion chamber is detected, the change in the engine speed and the change in the operating state. To obtain an engine control device capable of accurately detecting the charging efficiency of air filled in each cylinder, determining an appropriate fuel injection amount and ignition timing, and controlling an appropriate air-fuel ratio and ignition timing without being performed. With the goal.

According to the second aspect of the present invention, the charging efficiency can be accurately detected without being affected by the detection error of the in-cylinder pressure detected by the in-cylinder pressure sensor, and the air-fuel ratio and ignition timing with high accuracy can be obtained. It is an object of the present invention to obtain an engine control device capable of controlling the above.

According to the third aspect of the present invention, the average filling efficiency can be detected with high accuracy without being influenced by the detection error of the in-cylinder pressure detected by the in-cylinder pressure sensor and the operating state of the engine. An object is to obtain an engine control device capable of controlling the air-fuel ratio and the ignition timing.

According to the invention described in claim 4, the average filling efficiency can be detected with high accuracy without being affected by the in-cylinder pressure detection error detected by the in-cylinder pressure sensor and the operating condition of the engine. An object is to obtain an engine control device capable of controlling the fuel ratio and the ignition timing.

According to the invention of claim 5, a predetermined number of arithmetic averages can be calculated with high accuracy for each predetermined crank angle,
An object of the present invention is to obtain an engine control device that can detect the charging efficiency with high accuracy and can control the air-fuel ratio and ignition timing with high accuracy without being affected by the engine speed and the operating state of the engine.

[0020]

An engine control device according to a first aspect of the present invention uses an in-cylinder pressure sensor to determine an in-cylinder pressure difference ΔP in synchronization with two crank angles of a predetermined crank angle during a compression stroke. Measuring means for measuring, normalizing means for normalizing the in-cylinder pressure difference ΔP with a reference in-cylinder pressure difference ΔP ₀ obtained in an arbitrary reference operating state of the engine, and the normalized normalized in-cylinder pressure ΔP / ΔP. ₀ and a charging efficiency calculation means for calculating the charging efficiency Ce of the intake air amount of the engine on the basis of the previously measured charging efficiency Ce ₀ in the standard operation state, and a predetermined crank angle for which the charging efficiency Ce is calculated. The charging efficiency averaging means for averaging the charging efficiencies Ce obtained up to that time every time, the fuel injection amount of the engine, and the ignition based on the average charging efficiency Ce _ave obtained by the charging efficiency averaging means. Time It is provided with a an operation control means for determining a.

In the engine control device according to the second aspect of the present invention, the in-cylinder pressures measured at two predetermined crank angles during the compression stroke measured by the in-cylinder pressure sensor are averaged over several points before and after. Cylinder pressure average value P
An averaging means for calculating 1ave and P2ave is provided.

According to another aspect of the engine control apparatus of the present invention, the operating state detecting means for detecting the operating state of the engine, the engine rotational speed measuring means for measuring the engine rotational speed, and the operating state detecting means detect the operating state of the engine. Based on the operating state of the engine and the engine speed measured by the engine speed measuring means, the reference cylinder pressure difference ΔP ₀ and the reference charging efficiency Ce
A normalized reference value determining means for determining ₀ , a measuring means for measuring the in-cylinder pressure difference ΔP by a pressure sensor in synchronization with any or two arbitrary crank angles during the compression stroke, and a cylinder measured by this measuring means. a normalizing means for determining a normalized cylinder pressure difference [Delta] P / [Delta] P ₀ is normalized by the inner pressure difference [Delta] P _0, on the basis of this normalization cylinder pressure difference [Delta] P / [Delta] P ₀ and the reference charging efficiency Ce _0, the engine A charging efficiency calculating means for calculating the charging efficiency and a charging efficiency correcting means for correcting the charging efficiency calculated by the charging efficiency calculating means are provided.

An engine control apparatus according to a fourth aspect of the present invention is a cylinder temperature measuring means for measuring a gas temperature in an engine combustion chamber, a cooling water temperature measuring means for measuring a cooling water temperature of an engine, and an intake air temperature of the engine. The charging efficiency correction means for correcting the charging efficiency Ce of the engine based on the measured value of any of the intake air temperature measuring means for measuring is provided.

An engine control device according to a fifth aspect of the present invention is provided with a charging efficiency averaging means for arithmetically averaging a predetermined number of charging efficiencies Ce obtained up to that time for each predetermined crank. is there.

[0025]

According to the invention of claim 1, the in-cylinder pressure sensor measures the pressure difference ΔP in the combustion chamber in synchronization with two crank angles of a predetermined crank angle during the compression stroke, and the pressure difference ΔP in the combustion chamber is measured. The reference in-cylinder pressure difference ΔP ₀ in the reference operating state of the engine is normalized by the normalizing means to ΔP / ΔP ₀ , and the normalized signal ΔP / ΔP 0
₀ and the previously measured filling efficiency Ce at the above-mentioned standard operating condition
Based on ₀ , the charging efficiency calculation means calculates the charging efficiency Ce of the intake air amount of the engine. The charging efficiency Ce is calculated for each predetermined crank angle by using the charging efficiencies Ce obtained up to that time by the charging efficiency averaging means, and the engine is based on the weighted average charging efficiency Ce _ave. The fuel injection amount and the ignition timing are calculated by the calculation control means to control the engine, and noise is superimposed on the output value of the in-cylinder pressure sensor with the charging efficiency Ce obtained by the charging efficiency calculation means, or the engine suddenly bursts. There is an error in the cylinder pressure measured due to the intake pulsation that occurs,
Even if a measurement error occurs, by taking the weighted average of the charging efficiency measured up to that time and the charging efficiency detected now, it is possible to determine the accurate charging efficiency Ce with less measurement error, and to determine the air-fuel ratio It works to improve the control accuracy of the ignition timing.

In the second aspect of the present invention, the in-cylinder pressures measured at two predetermined crank angles during the compression stroke measured by the in-cylinder pressure sensor are averaged by the averaging means over several points before and after. By calculating the in-cylinder pressure average values P1ave and P2ave, it acts to reduce the measurement error with respect to the in-cylinder pressure value.

According to another aspect of the invention, the operating state detecting means detects the operating state of the engine, and
Measure the engine speed with the engine speed measuring means,
Based on the operating state and the engine speed, the reference combustion chamber pressure difference ΔP is set in advance in the reference operating state of the engine.
₀ , or at least one of the normalized in-cylinder pressure signal ΔP / ΔP ₀ and the charging efficiency Ce ₀ previously measured in the standard operating condition is corrected by the charging efficiency correcting means, and is measured by the operating condition and the engine speed. The deterioration of the accuracy of the charging efficiency Ce of the intake air amount of the engine is suppressed.

In the invention according to claim 4, the gas temperature in the combustion chamber of the engine is measured by the in-cylinder temperature measuring means,
Measure the engine cooling water temperature with cooling water temperature measuring means,
The intake air temperature of the engine is measured by the intake air temperature measuring means, and the charging efficiency Ce of the engine is corrected by the intake air temperature correcting means based on any one of these measured values, so that the engine is charged regardless of the combustion gas temperature of the engine. The accuracy of efficiency acts to suppress the deterioration.

In the invention described in claim 5, the charging efficiency averaging means calculates the charging efficiency Ce obtained by that time for each predetermined crank angle by arithmetically averaging a predetermined number of charging efficiency. It acts to average out.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine control device of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram of the embodiment. In FIG. 3, reference numeral 1 denotes an engine body, in which a cylinder head 1a is provided with an in-cylinder pressure sensor 8 as a pressure sensor, an in-cylinder temperature sensor 10 as in-cylinder temperature measuring means, and an ignition plug 9 in each cylinder. The in-cylinder pressure sensor 8 and the in-cylinder temperature sensor 10 are exposed in the combustion chamber of the cylinder.

An injector 4 is installed in an intake port 1b communicating with each cylinder of the engine body 1, and the intake port 1b is communicated with a throttle body 17 via an intake manifold 5. The throttle body 17 is provided with a throttle 13, and a throttle state detection sensor 15 for detecting whether or not the throttle 13 is fully closed.

A crank angle sensor 11 for detecting a preset crank angle of each cylinder is provided on a ring gear 12 connected to a crank shaft (not shown) of the engine body 1. An air-fuel ratio sensor 6 is installed at the confluence of the exhaust manifold 2 communicating with the exhaust port 1c of the engine body 1. In addition, 7 is a catalytic converter.

Reference numeral 14 is a control device (hereinafter referred to as ECU), such as a CPU (central processing unit) and RAM.
(Random access memory), ROM (Read only memory), Microcomputer consisting of input interface, and injector and spark plug built-in drive circuit. An air-fuel ratio sensor 6, an in-cylinder pressure sensor 8, an in-cylinder temperature sensor 10, a crank angle sensor 11, and a throttle state detection sensor 15 are connected to the input side of the ECU 14. Furthermore, this ECU 14
The injector 4 and the spark plug 9 are connected to the output side of the vehicle via a drive circuit (not shown) with a built-in ECU.

Here, FIG. 2 shows an in-cylinder pressure sensor 8 for detecting the pressure in the combustion chamber of this embodiment, and an installation drawing. In FIG. 2, 21 is a cylinder block, 22 is a cylinder head, and 23 is a piston. Reference numeral 26 is an in-cylinder pressure sensor, which is attached to the cylinder block 21. The pressure detecting portion 26a of the in-cylinder pressure sensor 26 is exposed to the pressure guiding portion 25 that communicates with the internal combustion chamber 24 of the engine, and detects the in-cylinder pressure.

The pressure detecting section 26a is adapted to measure the pressure through a pressure-bearing substance (not shown) (for example, silicone oil) or directly connected to a pressure converting element (not shown). The pressure conversion element uses a semiconductor pressure sensor. Also, as a pressure conversion element,
A piezoelectric element may be used.

First, an embodiment corresponding to the inventions described in claims 1, 3, 4, and 5 will be described. FIG. 1 is a block diagram showing the functions of the configuration of the essential parts of these inventions. In FIG. 1, 31 is an engine to be controlled, and 32 is an operating state detecting means. The operating state detecting means 32 is, for example, the throttle state detecting sensor 15 shown in FIG. As the throttle state detection sensor, a sensor as an operation state determination means for determining whether or not the throttle is fully closed as described above, or continuously detecting the throttle opening angle from the fully closed to fully opened throttle Alternatively, a throttle opening sensor (not shown) or a throttle position sensor (not shown) that detects that the throttle opening angle from fully closed to fully opened is within a predetermined angle range may be used. The operating state detecting means 32 may use an intake manifold pressure sensor (not shown) or an air flow sensor (not shown).

Reference numeral 33 is a crank angle detecting means for detecting the crank angle, for example, the crank angle sensor 1 shown in FIG.
1 is applicable. Reference numeral 34 denotes an in-cylinder pressure difference detecting means as a pressure sensor for detecting the in-cylinder pressure, which corresponds to the in-cylinder pressure sensor 8 in FIG. 3, for example. The cylinder pressure is
Based on the output obtained from the crank angle detection means 33, the in-cylinder pressure between predetermined crank angles is detected, and the in-cylinder pressure difference Δ
Detect P.

Reference numeral 35 denotes an in-cylinder temperature detecting means for detecting the in-cylinder temperature, which corresponds to the in-cylinder temperature sensor 10 of FIG. 3, for example. As the in-cylinder temperature detecting means, cooling water (not shown) circulating inside the engine body 1 of FIG.
It is also possible to use a cooling water temperature sensor (not shown) that detects the temperature. Since this cooling water temperature has a correlation with the in-cylinder temperature, the cooling water temperature can be used instead of the in-cylinder temperature.

As the in-cylinder temperature detecting means, an intake air temperature sensor (not shown) for detecting the intake air temperature of the engine may be used. Since the intake air temperature has a correlation with the in-cylinder temperature, the intake air temperature can be used as a substitute for the in-cylinder temperature.

Reference numeral 36 is an air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture operating in the engine, and corresponds to the air-fuel ratio sensor 6 of FIG. 3, for example. 31
Reference numeral 6 denotes an engine speed detecting means, which detects the engine speed from the time required to rotate a predetermined crank angle (for example, every 1 ° CA) based on the crank angle obtained from the crank angle detecting means 33. ..

Reference numeral 37 denotes a normalization reference value determining means, which is a cylinder pressure difference Δ for normalizing the cylinder pressure difference ΔP as the combustion chamber pressure difference ΔP detected by the cylinder pressure difference detecting means 34.
P ₀ (hereinafter referred to as reference cylinder pressure difference ΔP ₀ ) and reference charging efficiency Ce ₀ are determined based on the output of the operating state detection means 32 and the output of the engine speed detection means 316 described above. ..

Reference numeral 38 denotes an in-cylinder pressure difference normalizing means, which is an in-cylinder pressure difference ΔP obtained by the in-cylinder pressure difference detecting means 34 and a reference in-cylinder pressure difference obtained by the normalized reference value determining means 37. ΔP
_The normalized in-cylinder pressure difference ΔP / ΔP ₀ is determined from ₀ .

Numeral 39 is a charging efficiency calculating means, which is the normalized in-cylinder pressure difference Δ obtained by the in-cylinder pressure normalizing means 38 described above.
The charging efficiency Ce of the engine is calculated from P / ΔP ₀ and the standard charging efficiency Ce ₀ obtained by the normalized reference value determining means 37.

Reference numeral 310 denotes a charging efficiency correction means, which corrects the charging efficiency Ce based on the output of the in-cylinder temperature detection means 35. A charging efficiency averaging unit 317 arithmetically averages the charging efficiency Ce that is the output of the charging efficiency correction unit detected for each predetermined crank angle, or performs a weighted average with the charging efficiency Ce detected so far. To do.

Reference numeral 312 denotes a calculation control means, which calculates the average of the charging efficiency Ce _ave obtained by the charging efficiency averaging means 317, the output from the air-fuel ratio detecting means 36, and the output from the engine speed detecting means 316 to determine whether the engine is empty. The fuel ratio and ignition timing are determined and output.

Reference numeral 314 is an air-fuel ratio adjusting means, which controls the air-fuel mixture supplied to the engine in accordance with the air-fuel ratio control signal given from the arithmetic control means 312. The air-fuel ratio adjusting means 314 may be, for example, the injector 6 of FIG. 3 or a carburetor (not shown) capable of adjusting the air-fuel ratio by an electric signal.

Reference numeral 315 denotes an ignition timing adjusting means for performing ignition at an ignition timing according to an ignition timing control signal obtained from the arithmetic control means 312. For example, a full transistor type ignition device (power transistor switching circuit and A device including an ignition coil) and the spark plug 9 can be used.

Next, the principle of controlling the air-fuel ratio and the ignition timing in the present invention will be described. FIG. 4 shows the relationship between the crank angle and the in-cylinder pressure of the 4-cycle engine. A is a cylinder pressure waveform when the engine speed is 1500 rpm and the intake pipe pressure is −300 mmHg, and B is a cylinder pressure waveform when the engine speed is 3000 rpm and the intake pipe pressure is −400 mmHg. θ1 and θ2 are predetermined crank angles during the compression stroke, and θ1 is a crank angle after the intake valve is closed, for example, BTDC 90 ° CA. θ2 is a crank angle before ignition, for example, BTDC4
It is 0 ° CA. As shown in FIG. 4, the crank angle θ1
At this time, the in-cylinder pressure is P1, and the in-cylinder pressure at the crank angle θ2 is P2. The cylinder pressure difference ΔP in the case of the cylinder pressure waveform B in FIG. 4 is defined by the following equation (3). ΔP = P2-P1 (3)

Similarly, in the case of the in-cylinder pressure waveform A, the in-cylinder pressure difference ΔP can be defined. Here, the case of the in-cylinder pressure waveform A is set as a reference in-cylinder pressure difference ΔP ₀ as a normalized reference operation state as described later.

As described in the prior art, the in-cylinder pressure difference ΔP is shown in FIG. 2 between the in-cylinder pressure difference ΔP and the intake air amount Ga.
There are 4 relationships. Here, the intake air amount is charged into the cylinder at a charging efficiency Ce, that is, at an arbitrary operating condition relative to the weight when the air in the standard condition (for example, 1 atm / 0 ° C.) is charged into the cylinder of the engine. It will be handled as a ratio of the weight of air. That is, the relationship between the in-cylinder pressure difference ΔP and the charging efficiency Ce has the relationship shown in FIG. 7, as in FIG. Therefore, the filling efficiency Ce can be obtained by measuring the in-cylinder pressure difference ΔP.

However, as shown in FIG. 7, even if the in-cylinder pressure difference ΔP is the same, the charging efficiency C depends on the engine speed.
There is a problem that e varies. Further, since the absolute pressure value is used, the calibration must be accurate for each pressure sensor. When the calibration result varies, the measurement accuracy of the filling efficiency Ce deteriorates.

Therefore, for each engine speed,
The in-cylinder pressure difference ΔP in the above-described normalized reference operation state (for example, when the intake pipe internal pressure is −300 mmHg) is set as the reference in-cylinder pressure difference ΔP ₀ . Similarly, the charging efficiency Ce in the same normalization operation state is set as the reference charging efficiency Ce ₀ . Then, the in-cylinder pressure difference ΔP and the filling efficiency Ce in an arbitrary operating state are respectively referred to as the reference in-cylinder pressure difference Δ.
When normalized with P ₀ and the reference charging efficiency Ce ₀ , the relationship shown in FIG. 5 is obtained.

That is, by normalizing with the reference cylinder pressure difference ΔP ₀ and the reference charging efficiency Ce ₀ , a linear function is obtained, and the normalized charging efficiency (Ce / C
e ₀ ) can be expressed by a linear function using constants a and b as in the following expression (4). (Ce / Ce ₀ ) = a × (ΔP / ΔP ₀ ) + b (4)

Here, the coefficients a and b are calculated by changing operating conditions (Ce / Ce ₀ ), and measuring ΔP / ΔP ₀ , and expressed as shown in FIG. do it. Moreover, since the ratio of the in-cylinder pressure difference is used as in the equation (3), as long as the in-cylinder pressure sensor having the same characteristics is used to measure the pressure, the accuracy of the filling efficiency will not deteriorate due to the calibration variation. Absent.

Further, the relationship between FIGS. 7 and 5 is that the same in-cylinder temperature or the same cooling water temperature (for example, 80 ° C.),
Alternatively, it holds when the intake air temperature is the same. For example, using the filling efficiency when the cooling water temperature is 80 ° C. as a reference, it was calculated from the filling efficiency Ce for each cooling water temperature and the normalized in-cylinder pressure difference ΔP / ΔP _{0 by a} linear linear equation when the cooling water temperature is 80 ° C. The filling efficiency ratio K _tw (hereinafter, this ratio K _tw is referred to as a cooling water temperature correction coefficient) is shown in FIG. That is, the cooling water temperature correction coefficient K
_tw is defined by the following equation (5). K _tw = (filling efficiency at any cooling water temperature) / (cooling water temperature 8)
Filling efficiency at 0 ° C) (5)

Since the in-cylinder temperature has a correlation with the cooling water temperature, the ratio between the charging efficiency at an arbitrary in-cylinder temperature and the charging efficiency at the reference in-cylinder temperature is also shown in FIG.
It becomes the same relationship as. Therefore, the charging efficiency can be corrected based on the in-cylinder temperature.

Further, since the intake air temperature also has a correlation with the cooling water temperature, the ratio of the charging efficiency when the intake air temperature is a parameter and the charging efficiency when the intake air temperature is the reference is the same as in FIG. It becomes a relationship. Therefore, the charging efficiency may be corrected based on the intake air temperature.

If the charging efficiency Ce is calculated as described above, the charging efficiency Ce with good measurement accuracy can be obtained. However, for example, the in-cylinder pressure sensor output includes an error due to noise or transient output fluctuation. In this case, an error occurs in the in-cylinder pressure difference ΔP, and even if the correction is performed as described above, the filling efficiency includes the error. In order to eliminate such an error, a predetermined number of corrected charging efficiencies Ce measured for each predetermined crank angle are arithmetically averaged.

For example, as the arithmetic mean method,
There is a moving average method as described below. The charging efficiency that is currently detected is defined as Ce (0) for each predetermined crank angle. In addition, the charging efficiency detected i times before is calculated as Ce.
(I), Ce (n) is the filling efficiency detected n previous times
And The (n + 1) filling efficiencies are moving averaged according to the following equation (6) to obtain the average filling efficiency Ce _ave . Ce _ave = (ΣCe (i)) / (n + 1) (6)

As the averaging method, the following (7)
You may perform a weighted average like a formula. Ce _ave (j) = (1−K _ave ) × Ce (j) + K _ave × Ce _ave (j−1) (7) where (j) represents the current value and (j−1) is Only one represents the past value. K _ave is a weighting coefficient,
It takes a value between 0 and 1 inclusive. By thus averaging, it is possible to eliminate the detection error of the filling efficiency due to the detection error of the in-cylinder pressure difference ΔP.

As described above, the normalized cylinder pressure difference ΔP / Δ
It is possible to obtain the charging efficiency Ce of the engine with high measurement accuracy by normalizing using P ₀ and the reference charging efficiency Ce ₀ , correcting using the cooling water temperature, and arithmetically averaging for each measured crank angle.

Next, the logic for obtaining the charging efficiency Ce from the cylinder pressure and controlling the air-fuel ratio and the ignition timing will be described according to the flow chart of FIG. This logic is the ECU of FIG.
It is realized in 14.

First, this flow is processed in synchronization with the crank angle. However, as will be described later, step S123, step S127, and step S12.
The processing of engine load detection and cooling water temperature detection in 9 does not necessarily have to be synchronized with the crank angle. The timing at which this flow starts is, for example, the predetermined crank angle at which the in-cylinder pressure P1 at θ1 shown in FIG. 4 is obtained.

At the above timing, first in step S121, the in-cylinder pressure P1 at the crank angle θ1 and the in-cylinder pressure P2 at the crank angle θ2 are detected by, for example, the crank angle sensor 11 and the in-cylinder pressure sensor 8 in FIG. To do. Then, the in-cylinder pressure difference ΔP is calculated according to the above-described equation (3).

Next, in step S122, based on the output of the crank angle sensor, the engine speed Ne (rpm)
To measure. Next, in step S123, the load of the engine is detected. This is the operating state detecting means 32 of FIG.
As described above, a sensor for determining whether or not the throttle is fully closed as described above (hereinafter, this sensor is referred to as an idle sensor), or the throttle opening angle from the fully closed to fully open throttle is continuously set. It is determined using a throttle opening sensor that detects the throttle opening or a throttle position sensor that detects that the throttle opening angle from the fully closed to the fully opened throttle is within a predetermined angle range.

Further, an intake manifold internal pressure sensor or an air flow sensor may be used. For example, when the idle sensor is used, the operating state is detected as the idle state S _i when the throttle is fully closed and the non-idle state S _ni when the throttle is not fully closed. Further, for example, when a throttle opening sensor is used, the operating state is detected by the throttle opening α (degrees) from fully closed to fully open. When the throttle position sensor is used, the operating state is detected by the throttle opening states α1, α2, α3, α4 and the like.

When an intake manifold internal pressure sensor (not shown) is used, the operating state is detected by the intake manifold internal pressure Pb (mmHg). In the air flow sensor (not shown),
For example, the intake air amount G _ab (g) that flows by partially bypassing the intake pipe or the throttle upstream of the throttle.
To detect the operating condition.

The timing for detecting the engine load is not measured in synchronization with the crank angle as described above, but a value measured every predetermined time cycle is stored in the RAM, and step S123 is processed. You may use it at the timing.

Next, in step S124, step S
The engine speed Ne detected at 122 and step S12
At least one of the reference charging efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ is determined based on at least one of the operating states detected in 3. For example, in step S123,
When the idle sensor is used, as shown in Table 1 of FIG.
Reference charging efficiency C based on the operating states S _i and S _ni
e ₀ , the reference cylinder pressure difference ΔP ₀ is determined.

[0070]

[Table 1]

Further, for example, when the throttle opening sensor is used in step S123, a table lookup is performed based on the throttle opening α (degree) and the engine speed as shown in FIGS. Standard filling efficiency C
e ₀ , the reference cylinder pressure difference ΔP ₀ is determined. In this case, one of the reference charging efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ may be constant regardless of the throttle opening α.

Further, for example, when the throttle position sensor is used in step S123, as shown in FIG.
As shown in FIG. 12, the throttle opening states α1, α2, α
Table lookup based on 3, α4, etc. and engine speed to perform reference filling efficiency Ce ₀ , reference cylinder pressure difference ΔP _0.
To decide. In this case, either the reference charging efficiency Ce ₀ or the reference in-cylinder pressure difference ΔP ₀ may be constant regardless of the throttle opening state.

Further, for example, when the pressure sensor in the intake manifold is used in step S123, as shown in FIG.
As shown in FIG. 14, the reference charging efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ are determined by performing a table lookup based on the intake manifold internal pressure Pb and the engine speed. In this case, either the reference charging efficiency Ce ₀ or the reference in-cylinder pressure difference ΔP ₀ may be constant regardless of the intake manifold pressure Pb.

If an air flow sensor is used in step S123, a table lookup is performed based on the intake air amount G _ab and the engine speed, as shown in FIGS. ₀ , the reference in-cylinder pressure difference ΔP ₀ is determined. In this case, the standard filling efficiency Ce ₀ ,
Either one of the reference cylinder pressure difference ΔP ₀ is the intake air amount G _ab
It may be constant regardless of.

Next, in step S125, step S
Using the in-cylinder pressure difference ΔP measured in 121 and the reference in-cylinder pressure difference ΔP ₀ determined in step S124, the normalized in-cylinder pressure difference ΔP / ΔP ₀ is calculated.

Next, in step S126, step S
Reference charging efficiency Ce ₀ determined in step 124 and step S12
Using the normalized in-cylinder pressure difference ΔP / ΔP ₀ calculated in 5,
The filling efficiency CeΔP is calculated according to the following equation (8) using the coefficients a and b of the above equation (4). CeΔP = Ce ₀ × (a × (ΔP / ΔP ₀ ) + b) (8)

Next, in step S127, for example,
The in-cylinder temperature is measured using the in-cylinder temperature sensor 10 in FIG. 3 and the cooling water temperature sensor described above. Here, the cooling water temperature T _w measured by the cooling water temperature sensor will be described as an example. As described above, the cooling water temperature is not measured in synchronization with the crank angle, but a value measured at every predetermined time cycle is stored in the RAM and may be used at the timing of processing step S127. Good.

Next, in step S128, step S
The filling efficiency CeΔP is calculated using the filling efficiency CeΔP obtained in 126 and the cooling water temperature T _w obtained in step S127. First, the cooling water temperature correction coefficient K _{tw is calculated} based on the relationship shown in FIG. 6 from the cooling water temperature T _w .
Ask for. This is the cooling water temperature T _w as shown in Table 2.
The table lookup of the cooling water temperature correction coefficient K _tw based on

[0079]

[Table 2]

Cooling water temperature correction coefficient K thus obtained
_{Using tw} , the filling efficiency Ce is calculated according to the following equation (9). Ce = K _tw × CeΔP (9)

Next, in step S131, step S
The filling efficiency Ce obtained in 128 is averaged to calculate the average filling efficiency Ce _ave . This performs the averaging process according to the above-mentioned equations (6) and (7). First, the case where the calculation is performed according to the equation (6) will be described. Step S12
When 8 is completed, the current charging efficiency Ce (0) described above is obtained.
Is obtained. At this time, the past n charging efficiencies Ce (1) to Ce (n) are stored in, for example, the RAM built in the ECU 14 of FIG.

If n charging efficiencies Ce have not been detected yet, it is sufficient to use only the detected number and average them. Further, for example, the following calculation may not be performed until the n charging efficiencies Ce have been detected.
(N + 1) packing efficiencies Ce thus obtained
The average filling efficiency Ce _ave is calculated by the equation (6) using Ce (n) from (0).

Next, the case where the calculation is performed according to the equation (7) will be described. At the end of step S128, the current charging efficiency Ce (j) described above is obtained. At this time, the average charging efficiency Ce _ave (j-
1) is stored in the RAM incorporated in the ECU 14 of FIG. 3, for example. If the average charging efficiency Ce _ave (j-1) has not been detected yet, the average charging efficiency Ce _ave (j-1) is set to the same value as the currently detected Ce (j), for example, the average charging efficiency Ce _ave (j-1) is detected. The following calculation may not be performed until the end.

The average packing efficiency Ce thus obtained
_{Using ave} (j-1), the average charging efficiency Ce _ave (j) is calculated by the equation (7). This average filling efficiency Ce
_ave (j) is the average filling efficiency C obtained in step S131
e _ave . In this way, the average filling efficiency Ce _ave obtained in step S131 is the filling efficiency with good measurement accuracy obtained by the present invention.

Next, at step S129, the air-fuel ratio is measured by using the air-fuel ratio detecting means shown in FIG. 1, for example, the air-fuel ratio sensor 6 shown in FIG. The timing of this measurement is not measured in synchronization with the crank angle, but the value measured every predetermined time cycle is stored in the RAM in the same manner as in step S123 and step S127 described above, and this step S1 is performed.
29 may be used at the timing of processing. This air-fuel ratio sensor is, for example, an oxygen concentration sensor, and it is smaller than the theoretical air-fuel ratio 14.7 (called rich at this time) and larger than 14.7 (called lean at this time). ) You can judge the case.

The air-fuel ratio correction coefficient K _fb is determined according to the output of this sensor. This air-fuel ratio correction coefficient K _fb is for feedback controlling the fuel injection amount so that the air-fuel ratio adjusting means 314 of FIG. The air-fuel ratio correction coefficient K _fb is set to K _fb = 1.0 when the air-fuel ratio is a desired value. Further, when the air-fuel ratio sensor determines that the air-fuel ratio is rich, the fuel injection amount is reduced by subtracting K _fb by a predetermined value for each process of step S129. Also,
When the air-fuel ratio sensor determines that the engine is lean, the fuel injection amount is increased by adding K _fb by a predetermined value for each process of step S129. In this way, the air-fuel ratio correction coefficient _Kfb is calculated.

Next, in step S130, step S
Based on the average charging efficiency Ce _ave obtained in 131, the fuel injection amount and the ignition timing are determined, and the air-fuel ratio and the ignition timing are adjusted. First, the fuel injection amount is the injector 4 of FIG.
The fuel injection pulse width T _i (ms) for adjusting is determined according to the equation (10). T _i = K × K _fb × Ce _ave (10) K in the equation (10) is an air-fuel ratio constant, which is a desired air-fuel ratio according to the average charging efficiency Ce _ave , for example, the air-fuel ratio 1
It is a coefficient for converting into a fuel injection pulse width T _i of 4.7. K _fb is the air-fuel ratio correction coefficient determined in step S129.

A signal is sent from the ECU 14 of FIG. 3 to drive the injector 4 based on the result of the fuel injection pulse width calculation of the equation (10). The fuel injection pulse width T _i may be corrected according to the states of a battery (not shown) and a battery voltage detection device (not shown) attached to the engine. In this way, the air-fuel ratio of the engine is controlled.

Further, the ignition timing is, for example, the engine speed Ne and the fuel injection pulse width T _i as shown in FIG. 17 according to the above-mentioned fuel injection pulse width T _i and the engine speed Ne obtained in step S122. The ignition timing is determined from the two-dimensional map table by table lookup. According to this ignition timing, the ECU of FIG.
A signal is sent from 14 to drive the spark plug 9. Also,
The ignition timing is the engine speed Ne as shown in FIG.
Alternatively, the table may be looked up from a two-dimensional map table that determines the ignition timing from the charging efficiency Ce. As described above, the air-fuel ratio of the engine and the ignition timing are controlled according to the flowchart of FIG.

Even if the engine described above is a multi-cylinder engine, the air-fuel ratio and the ignition timing can be controlled in accordance with the above-described procedure for each cylinder. In that case, at least one of the reference cylinder pressure difference ΔP ₀ and the reference charging efficiency Ce ₀ may be set to different values for each cylinder.

In the case of a multi-cylinder engine, the charging efficiency Ce of each cylinder can be obtained for each cylinder.
The average charging efficiency Ce _ave may be calculated by performing the process of step S131 of FIG. 8 on the charging efficiency Ce detected in that order.

Next, an embodiment of the invention described in claim 2 will be described with a particular focus on the points different from FIG. The description of the overlapping parts will be omitted. FIG. 19 is a block diagram showing the function of the configuration of the essential parts of the invention of claim 2. In FIG. 19, reference numeral 251 denotes an engine to be controlled, and 252
Is an operating state detecting means. This operating state detection means 2
One example of 52 is the throttle state detection sensor 15 shown in FIG. 3, for example.

Reference numeral 253 denotes a crank angle detecting means for detecting the crank angle, which corresponds to, for example, the crank angle sensor 11 shown in FIG. Reference numeral 254 denotes an in-cylinder pressure detecting means for detecting the in-cylinder pressure, which corresponds to the in-cylinder pressure sensor 8 in FIG. 3, for example. For the in-cylinder pressure, the in-cylinder pressure P at a predetermined crank angle is detected based on the output obtained from the crank angle detecting means 253.

Reference numeral 255 denotes an in-cylinder temperature detecting means for detecting the in-cylinder temperature, and one example thereof is the in-cylinder temperature sensor 10 shown in FIG. Reference numeral 256 is an air-fuel ratio detecting means for detecting the air-fuel ratio of the air-fuel mixture operating in the engine, and corresponds to, for example, the air-fuel ratio sensor 6 in FIG. 2516 is an engine speed detecting means,
Based on the crank angle obtained from the crank angle detection means 253, the engine speed is detected from the time required to rotate a predetermined crank angle (for example, every 1 ° CA).

[0095] 257 is a normalized reference value determining means, described later cylinder pressure difference calculating unit cylinder pressure difference ΔP to normalize the cylinder pressure difference ΔP detected by 2518 ₀ and the reference charging efficiency C
e ₀ is determined based on the output of the operating state detecting means 252 and the output of the engine speed detecting means 2516 described above.

Reference numeral 2517 denotes an in-cylinder pressure averaging means, which is a characteristic means of the present invention, and is a crank angle detecting means 25.
Predetermined 2 for calculating the cylinder pressure difference ΔP based on the output of 3
The in-cylinder pressure P, which is the output of the in-cylinder pressure detecting means 254, is averaged over several points before and after each crank angle. The averaging means is, for example, an arithmetic sum average over several points before and after each crank angle. The in-cylinder pressure averaging means obtains the in-cylinder pressure average value P _ave at two predetermined crank angles.

Reference numeral 2518 denotes an in-cylinder pressure average value P at two predetermined crank angles, which is the output of the in-cylinder pressure averaging means 2517.
_This is means for calculating the in-cylinder pressure difference ΔP from _ave . 258
Is an in-cylinder pressure normalizing means, and is an in-cylinder pressure difference calculating means 2
The normalized in-cylinder pressure difference ΔP / ΔP ₀ is determined from the in-cylinder pressure difference ΔP obtained in 518 and the reference in-cylinder pressure difference ΔP ₀ obtained in the normalized reference value determining means 257.

Reference numeral 259 denotes a charging efficiency calculating means, which is the normalized in-cylinder pressure difference ΔP / ΔP ₀ obtained by the in-cylinder pressure normalizing means 258 and the reference obtained by the normalized reference value determining means 257. From the charging efficiency Ce ₀ to the engine charging efficiency C
It calculates e. Reference numeral 2510 denotes a charging efficiency correction means, which corrects the charging efficiency Ce based on the output of the in-cylinder temperature detection means 255.

Reference numeral 2512 denotes an arithmetic control means, which is the charging efficiency Ce after correction by the in-cylinder temperature obtained by the charging efficiency correcting means 2510, the output from the air-fuel ratio detecting means 256, and the output from the engine speed detecting means. The engine air-fuel ratio and ignition timing are determined and output.

Further, reference numeral 2514 is an air-fuel ratio adjusting means for controlling the air-fuel mixture supplied to the engine in accordance with the air-fuel ratio control signal given from the arithmetic control means 2512. The air-fuel ratio adjusting means 2514 is, for example,
It is possible to use the injector 6 of FIG. 3 or a carburetor capable of adjusting the air-fuel ratio by an electric signal.

Reference numeral 2515 denotes an ignition means for performing ignition at an ignition timing corresponding to an ignition timing control signal obtained from the arithmetic control means 2512. For example, a full transistor type ignition device and an ignition plug 9 are provided. Can be used.

Next, the cylinder pressure difference ΔP in this embodiment.
Since the principle of detecting the charging efficiency Ce from is the same as that of the above-described embodiment, the description thereof will be omitted. However, the invention of claim 2 is different in that, for example, the in-cylinder pressure at the crank angle θ1 is averaged as described later. This point will be described in detail in the description of the flowchart in FIG.

Next, the logic for obtaining the charging efficiency Ce from the cylinder pressure and controlling the air-fuel ratio and the ignition timing will be described in accordance with the flowchart of FIG. This logic is EC in Figure 3
It is realized in U14.

First, this flow is processed in synchronization with the crank angle. However, as will be described later, step S263, step S267, and step S26.
The processing of engine load detection and cooling water temperature detection in 9 does not necessarily have to be synchronized with the crank angle. The timing at which this flow starts is, for example, a predetermined angle before θ1 at which the arithmetic mean for obtaining the in-cylinder pressure P1 at θ1 shown in FIG. 4 is started.

This will be described with reference to FIG.
In FIG. 21, the in-cylinder pressure average value P1 _ave at the crank angle θ1
In order to obtain the above, a case where n in-cylinder pressures at the crank angle θ1 and a total of (2n + 1) in-cylinder pressures are detected and arithmetically averaged is shown. In this case, the crank angle θ1 (-
The flow of FIG. 20 starts at the timing of n). The logic for _{obtaining the} in-cylinder pressure average values P1 _ave and P2 _ave will be described later.

At the above timing, first in step S2611, the in-cylinder pressure average values P1 _ave and P2 _{ave are} calculated.
In order to obtain, the (2n + 1) in-cylinder pressures before and after θ1 and θ2 are detected. Cylinder pressure average value P1 _ave and P
2 _ave detects the in-cylinder pressure for each predetermined crank angle (for example, every 1 ° CA) before and after (2n + 1) crank angles θ1 and θ2, and arithmetically averages them. It will be described with reference to FIG. First, the in-cylinder pressure average value P1 _ave is the crank angle θ1 (-
n) to θ1 (n) for each predetermined crank angle, the cylinder pressure P
From (1−−n) to P1 (n), (2n + 1) in-cylinder pressures are sequentially measured, and after the in-cylinder pressure P1 (n) is measured, the next (1
Calculate according to formula 1). P1 _ave = (ΣP1 (i)) / (2n + 1) (11) The in-cylinder pressure average value P2 _ave is calculated in the same manner. In step S2611, the in-cylinder pressures P1 (i) and P2 (i) are detected.

Next, in step S2612, the in-cylinder pressures P1 (i) and P2 (i) obtained in step S2611 are arithmetically averaged according to the above equation (11). Next, in step S261, the above-mentioned step S261 is performed.
Cylinder pressure average value P1 at crank angle θ1
_Using the in-cylinder pressure average value P2 _ave at _ave and the crank angle θ2, the in-cylinder pressure difference ΔP is calculated according to the above equation (3). In the next step S262, the engine speed Ne (rpm) is measured based on the output of the crank angle sensor.

Next, in step S263, the load on the engine is detected. This is the operating state detecting means 2 of FIG.
As described in 52, a sensor for determining whether or not the throttle is fully closed as described above (hereinafter, this sensor is referred to as an idle sensor), or a throttle opening angle from fully closed to fully opened The determination is performed by using a throttle opening sensor that continuously detects or a throttle position sensor that detects that the throttle opening angle from the fully closed to the fully opened throttle is within a predetermined angle range. Alternatively, an intake manifold pressure sensor or an air flow sensor may be used.

For example, when the idle sensor is used, the operating state is detected as the idle state S _i when the throttle is fully closed and the non-idle state S _ni when the throttle is not fully closed. For example, when a throttle opening sensor is used, the throttle opening α from fully closed to fully open
The operating status is detected in (degrees). When the throttle position sensor is used, the throttle opening state α1, α2,
The operating state is detected by α3, α4, etc. When an intake manifold internal pressure sensor (not shown) is used, the operating state is detected by the intake manifold internal pressure Pb (mmHg). An air flow sensor (not shown) detects the operating state by, for example, an intake pipe upstream of the throttle or an intake air amount G _ab (g) that flows by partially bypassing the throttle.

The timing for detecting the engine load is not measured in synchronization with the crank angle as described above, but a value measured every predetermined time cycle is stored in the RAM, and this step S263 is processed. You may use it at the timing.

Next, in step S264, step S
The engine speed Ne detected in 262 and step S26
At least one of the reference charging efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ is determined based on at least one of the operating states detected in 3. For example, in step S263,
When the idle sensor is used, as shown in Table 1, the reference charging efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ are determined based on the operating states S _i and S _ni .

Further, for example, when the throttle opening sensor is used in step S263, a table lookup is performed based on the throttle opening α (degrees) and the engine speed as shown in FIGS. The filling efficiency Ce ₀ and the reference in-cylinder pressure difference ΔP ₀ are determined. In this case, either the reference charging efficiency Ce ₀ or the reference in-cylinder pressure difference ΔP ₀ may be constant regardless of the throttle opening α.

Further, for example, in step S263, whether the throttle position sensor is used, the intake manifold pressure sensor is used, or the air flow sensor is used, in step S123 of the flow chart of FIG. Since it is the same as the processing, it is omitted.

Next, in step S265, step S
Using the in-cylinder pressure difference ΔP measured in 261 and the reference in-cylinder pressure difference ΔP ₀ determined in step S264, the normalized in-cylinder pressure difference ΔP / ΔP ₀ is calculated. Next, in step S266, using the reference charging efficiency Ce ₀ determined in step S264 and the normalized in-cylinder pressure difference ΔP / ΔP ₀ calculated in step S265, the same coefficients a and b as in the above-described equation (4) are used. According to formula (8), the filling efficiency CeΔP
Is calculated.

Next, in step S267, for example,
The in-cylinder temperature is measured using the in-cylinder temperature sensor 10 in FIG. 3 and the cooling water temperature sensor described above. Here, the cooling water temperature T _w measured by the cooling water temperature sensor will be described as an example. As described above, the cooling water temperature is not measured in synchronization with the crank angle, but a value measured at every predetermined time cycle is stored in the RAM, and may be used at the timing of processing step S267. Good.

Next, in step S268, step S
The charging efficiency CeΔP calculated in step 266 and the cooling water temperature T _w calculated in step S267 are used to correct the charging efficiency CeΔP to calculate the charging efficiency Ce. First, the cooling water temperature correction coefficient K _{tw is calculated} based on the relationship shown in FIG. 6 from the cooling water temperature T _w .
Ask for. This can be done, for example, by looking up the cooling water temperature correction coefficient K _tw from Table 2 based on the cooling water temperature T _w . Cooling water temperature correction coefficient K obtained in this way
_{Using tw} , the filling efficiency Ce is calculated according to the equation (9).

Next, in step S269, the air-fuel ratio is measured using the air-fuel ratio detecting means shown in FIG. 19, for example, the air-fuel ratio sensor 6 shown in FIG. As for the timing of this measurement, similar to steps S263 and S267 described above, the value measured at every predetermined time cycle is stored in the RAM without being measured in synchronization with the crank angle.
69 may be used at the timing of processing. This air-fuel ratio sensor is, for example, an oxygen concentration sensor and can determine whether it is rich or lean.

The air-fuel ratio correction coefficient K _fb is determined according to the output of this air-fuel ratio sensor. This air-fuel ratio correction coefficient K _fb is
As will be described later, the air-fuel ratio adjusting means 2514 of FIG. 19 feedback-controls the fuel injection amount so as to obtain a predetermined air-fuel ratio. This air-fuel ratio correction coefficient K
_fb is, for example, if the desired air-fuel ratio is K _fb =
Set to 1.0.

When the air-fuel ratio sensor determines that the air-fuel ratio is rich, K _{fb is} set for each processing of step S269.
Is subtracted by a predetermined value to decrease the fuel injection amount, and when the air-fuel ratio sensor determines that the fuel is lean, K _fb is added by a predetermined value for each process of step S269 and the fuel injection is performed. Increase the amount. In this way, the air-fuel ratio correction coefficient _Kfb is calculated.

Next, in step S2610, the fuel injection amount and the ignition timing are determined based on the charging efficiency Ce obtained in step S268, and the air-fuel ratio and the ignition timing are adjusted. First, as the fuel injection amount, the fuel injection pulse width T _i (ms) for adjusting the injector 4 of FIG. 3 is determined according to the equation (10). A signal is sent from the ECU 14 of FIG. 3 to drive the injector 4 based on the result of the fuel injection pulse width calculation of the equation (10). In this way, the air-fuel ratio of the engine is controlled.

Further, the ignition timing is determined by, for example, the engine speed Ne and the fuel injection pulse width T as shown in FIG. 17 according to the fuel injection pulse width T _i described above and the engine speed Ne obtained in step S262. _It is determined by table lookup from a two-dimensional map table that determines the ignition timing from _i . According to this ignition timing, the ECU 1 of FIG.
4 sends a signal to drive the spark plug 9.

The ignition timing is determined from the engine speed Ne and the charging efficiency Ce as shown in FIG.
It may be determined by table lookup from the dimension map table. As described above, the air-fuel ratio of the engine and the ignition timing are controlled according to the flowcharts of FIGS. Needless to say, the engine described above can be similarly applied even if it is a multi-cylinder engine.

[0123]

As described above, according to the first aspect of the present invention, the pressure in the engine combustion chamber is detected by the pressure sensor, and two arbitrary cranks during the compression stroke are detected based on the detection force of the pressure sensor. The in-cylinder pressure difference ΔP between the angles is measured by the measuring means, the engine speed is measured by the rotation speed measuring means, and the measured combustion chamber pressure difference ΔP is obtained in any reference state of the engine. The normalized in-cylinder pressure difference ΔP / ΔP ₀ is calculated by normalizing with ΔP ₀ by the normalizing means, and the normalized in-cylinder pressure difference ΔP / ΔP ₀ and the reference filling efficiency Ce in the arbitrary reference state during the compression stroke. _The charging efficiency calculation means calculates the charging efficiency Ce of the engine using a linear linear equation based on _0, and the charging efficiency Ce is arithmetically averaged or weighted averaged for each predetermined crank angle to obtain average charging. Efficiency Ce _ave is calculated, the fuel injection amount and the ignition timing are determined by the arithmetic control means based on the average charging efficiency Ce _ave , and the air-fuel ratio of the engine and the ignition timing are controlled. The engine control device capable of detecting the average charging efficiency Ce _ave with high measurement accuracy without being affected by the error in measuring the in-cylinder pressure value and capable of controlling the air-fuel ratio and the ignition timing with high control accuracy. Can be obtained.

According to the invention described in claim 2, in addition to the means of claim 1, means for averaging the in-cylinder pressure P measured in synchronization with any two crank angles during the compression stroke is added. The filling efficiency Ce is measured by
Since the air-fuel ratio of the engine and the ignition timing are controlled by the arithmetic control means based on e, the filling efficiency Ce can be detected with high accuracy without being affected by the detection error of the in-cylinder pressure detected by the in-cylinder pressure sensor. Therefore, it is possible to obtain the engine control device capable of controlling the air-fuel ratio and the ignition timing with high accuracy.

According to the third aspect of the present invention, in addition to the configurations of the first and second aspects of the present invention, an operating state detecting means for detecting the operating state of the engine, and an arbitrary reference for the engine are provided. Pressure difference ΔP ₀ in the combustion chamber,
And the above-described filling efficiency C0 by normalizing the reference filling efficiency Ce ₀ in the above-mentioned arbitrary reference state based on the value corrected based on the operating state detected by the above-mentioned operating state detecting means.
Since the charging efficiency Ce is measured by adding a means for correcting and calculating e, the arithmetic control means controls the air-fuel ratio and the ignition timing of the engine based on the charging efficiency Ce. The average charging efficiency Ce _ave is not affected by the detection error of the in-cylinder pressure detected by the sensor and is not affected by the operating state of the engine.
Can be detected with high measurement accuracy, and an engine control device that can perform highly accurate control of the air-fuel ratio and ignition timing can be obtained.

According to the invention described in claim 4, in addition to the configuration of the invention described in claims 1 and 2, a combustion chamber temperature measuring means for measuring the temperature of the combustion chamber of the engine, and the combustion chamber temperature. A means for correcting and calculating the above-mentioned filling efficiency Ce according to the temperature in the combustion chamber obtained by the measuring means is added to measure the filling efficiency Ce, and the air-fuel ratio of the engine and the ignition are calculated based on the filling efficiency Ce. Since the timing is controlled by the arithmetic control means, the average charging efficiency Ce _ave is not affected by the detection error of the in-cylinder pressure detected by the in-cylinder pressure sensor and is not affected by the operating state of the engine. It is possible to obtain an engine control device that can detect with high measurement accuracy and can control the air-fuel ratio and ignition timing with high accuracy.

According to the invention of claim 5, claim 1
Since the charging efficiency Ce calculated by the charging efficiency calculating means in the invention described in 1) is calculated by the charging efficiency averaging means, a predetermined number of arithmetic operations are performed.
It is possible to obtain the engine control device that can determine the accurate charging efficiency Ce with few measurement errors and improve the control accuracy of the air-fuel ratio and the ignition timing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a main part of an engine control device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of an in-cylinder pressure sensor that detects a pressure in a combustion chamber of an engine to which the embodiment described above is applied and a peripheral portion thereof.

FIG. 3 is a configuration explanatory view of a main part of an engine to which the embodiment is applied.

FIG. 4 is a relationship diagram of a crank angle and an in-cylinder pressure for explaining the embodiment.

FIG. 5 is a relationship diagram of the normalized in-cylinder pressure difference ΔP / ΔP ₀ and the normalized charging efficiency Ce / Ce ₀ for explaining the embodiment.

FIG. 6 is a cooling water temperature T of an engine to which the above embodiment is applied.
It is a relationship diagram of _w and cooling water temperature correction coefficient _Ktw .

FIG. 7 is a relationship diagram between a cylinder pressure difference ΔP and a charging efficiency Ce of the engine to which the embodiment is applied.

FIG. 8 is a flowchart showing the logic for determining the filling efficiency Ce from the cylinder pressure difference ΔP and controlling the air-fuel ratio and the ignition timing, for explaining the operation of the above embodiment.

FIG. 9 is a diagram showing a reference charging efficiency Ce when the operating state is judged by using a throttle opening sensor for explaining the operation of the embodiment.
It is a two-dimensional map that determines ₀ .

FIG. 10 is a two-dimensional map for determining the reference in-cylinder pressure difference ΔP ₀ by using the throttle opening sensor to determine the operating state, for explaining the operation of the above embodiment.

FIG. 11 is a two-dimensional map for determining the reference charging efficiency Ce ₀ by determining the operating state using the throttle position sensor for explaining the operation of the above embodiment.

FIG. 12 is a two-dimensional map for determining the reference in-cylinder pressure difference ΔP ₀ by using the throttle position sensor to determine the operating state, for explaining the operation of the above embodiment.

FIG. 13 is a two-dimensional map for determining the reference charging efficiency Ce ₀ by using the intake manifold pressure sensor to determine the operating state, for explaining the operation of the above embodiment.

FIG. 14 is a two-dimensional map for determining the reference in-cylinder pressure difference ΔP ₀ by using the intake manifold pressure sensor to determine the operating state, for explaining the operation of the above embodiment.

FIG. 15: Reference charging efficiency Ce ₀ is determined by determining an operating state using an air flow sensor for explaining the operation of the above embodiment.
2 is a two-dimensional map that determines

FIG. 16 is a reference cylinder pressure difference ΔP obtained by determining an operating state using an air flow sensor for explaining the operation of the embodiment.
It is a two-dimensional map that determines ₀ .

FIG. 17 is a two-dimensional map for determining the ignition timing from the engine speed Ne and the fuel injection pulse width T _i for explaining the operation of the above embodiment.

FIG. 18 is a two-dimensional map for determining the ignition timing from the engine speed Ne and the charging efficiency Ce for explaining the operation of the embodiment.

FIG. 19 is a block diagram showing a configuration of a main part of an engine control device according to a second embodiment of the present invention.

20 is a flowchart showing a logic for controlling the air-fuel ratio and the ignition timing by obtaining the charging efficiency Ce from the in-cylinder pressure difference ΔP according to the embodiment of FIG.

FIG. 21 is an explanatory diagram showing the principle of averaging the measured in-cylinder pressures for explaining the operation of the embodiment of FIG.

FIG. 22 is a structural explanatory diagram of a main part of an engine to which a conventional engine control device is applied.

FIG. 23 is a cylinder pressure waveform diagram during ignition and motoring controlled by a conventional engine control device.

FIG. 24 is a relationship diagram between a conventional cylinder pressure difference ΔP of an engine control device and an engine and a filling air amount Ga.

FIG. 25 is a relational diagram of a conventional engine speed and a fuel injection time at which a logical air-fuel ratio is obtained.

[Explanation of symbols]

 31 engine 32 operating state detecting means 33 crank angle detecting means 34 in-cylinder pressure difference detecting means 35 in-cylinder temperature detecting means 36 air-fuel ratio detecting means 37 normalization reference value determining means 38 in-cylinder pressure difference normalizing means 39 filling efficiency calculating means 251 Engine 252 Operating State Detecting Means 253 Crank Angle Detecting Means 254 Cylinder Pressure Detecting Means 255 Cylinder Temperature Detecting Means 256 Air-Fuel Ratio Detecting Means 257 Normalization Reference Value Determining Means 258 Cylinder Pressure Difference Normalizing Means 259 Filling Efficiency Calculating Means 2510 Filling efficiency correction means 2512 Calculation control means 2514 Air-fuel ratio adjustment means 2515 Ignition timing adjustment means 2516 Engine speed detection means 2517 Cylinder pressure averaging means 2518 Cylinder pressure difference calculation means 310 Filling efficiency correction means 312 Calculation means 314 Air-fuel ratio adjustment Means 315 Ignition timing adjusting hand 316 engine speed detecting means 317 charging efficiency averaging means

[Procedure amendment]

[Submission date] April 15, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 20

[Correction method] Change

[Correction content]

FIG. 20

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichi Washino 8-1-1 Tsukaguchihonmachi, Amagasaki-shi, Hyogo Sanryo Electric Co., Ltd. Industrial Systems Research Institute

Claims (5)

[Claims] 1. A pressure sensor for detecting a pressure in an engine combustion chamber; a crank angle sensor for detecting a crank angle;
Measuring means for measuring the in-cylinder pressure difference ΔP in synchronization with any two crank angles during the compression stroke by the pressure sensor;
Normalizing means for normalizing the in-cylinder pressure difference ΔP measured by the measuring means with a reference in-cylinder pressure difference ΔP ₀ obtained in the reference state of the engine to determine a normalized in-cylinder pressure difference ΔP / ΔP ₀ ; A charging efficiency calculating means for calculating the charging efficiency Ce of the engine based on the normalized cylinder pressure difference ΔP / ΔP ₀ normalized by the normalizing means and the reference charging efficiency Ce ₀ in the arbitrary reference state. The filling efficiency Ce calculated by the filling efficiency calculation means is averaged to obtain the average filling efficiency C.
Engine control including charging efficiency averaging means for calculating e _ave, and calculation control means for controlling the air-fuel ratio and ignition timing of the engine based on the average charging efficiency Ce _ave obtained by the charging efficiency averaging means apparatus. 2. A pressure sensor for detecting a pressure in an engine combustion chamber, a crank angle sensor for detecting a crank angle,
Averaging means for averaging the in-cylinder pressure P measured by the pressure sensor in synchronization with an arbitrary crank angle during the compression stroke,
Measuring means for measuring the in-cylinder pressure difference ΔP from the in-cylinder pressure P averaged by the averaging means, and the in-cylinder pressure difference ΔP measured by the measuring means in the reference cylinder of the engine. a normalizing means for determining a normalized cylinder pressure difference [Delta] P / [Delta] P ₀ is normalized by the pressure difference [Delta] P _0, normalized the normalization cylinder pressure difference [Delta] P / [Delta] P ₀ and the optional at this normalization means A charging efficiency calculating means for calculating the charging efficiency Ce of the engine based on the reference charging efficiency Ce ₀ in the reference state, and the charging efficiency Ce calculated by the charging efficiency calculating means are averaged to calculate an averaged charging efficiency Ce _ave . An engine control device comprising a charging efficiency averaging means and an arithmetic control means for controlling the air-fuel ratio and ignition timing of the engine based on the average charging efficiency Ce _ave obtained by the charging efficiency averaging means. 3. An operating state detecting means for detecting an operating state of the engine, and a determining means for determining the operating state based on a detected value of the operating state detected by the operating state detecting means.
An engine speed measuring means for measuring the engine speed, a reference cylinder pressure difference Δ based on the operating state determined by the determining means and the measurement value measured at the engine speed.
Normalized reference value determination means for determining P ₀ and reference charging efficiency Ce ₀ , and measurement means for measuring the in-cylinder pressure difference ΔP in synchronization with any or two arbitrary crank angles during the compression stroke by the pressure sensor. , Normalizing means for determining the normalized in-cylinder pressure difference ΔP / ΔP ₀ by normalizing with the in-cylinder pressure difference ΔP ₀ measured by the measuring means, and the normalized in-cylinder pressure difference ΔP / Δ.
A filling efficiency calculation means for calculating the filling efficiency Ce of the engine based on P ₀ and the reference filling efficiency Ce ₀ , a filling efficiency correction means for correcting the filling efficiency Ce calculated by the filling efficiency calculation means, and this filling and charging efficiency averaging means for calculating the average charging efficiency Ce _ave by averaging the corrected charging efficiency in efficiency correction means, empty the engine based on the average charging efficiency Ce _ave obtained in this charging efficiency averaging means An engine control device comprising an arithmetic control unit for controlling a fuel ratio and an ignition timing. 4. A pressure sensor for detecting a pressure in a combustion chamber of an engine, a crank angle sensor for detecting a crank angle, and a pressure difference in a cylinder in synchronization with any two crank angles during a compression stroke by the pressure sensor. Measuring means for measuring ΔP, and the in-cylinder pressure difference ΔP measured by this measuring means is normalized by the reference in-cylinder pressure difference ΔP ₀ obtained in the reference state of the engine to normalize the in-cylinder pressure difference ΔP / ΔP _0. And a charging efficiency Ce of the engine based on the normalized in-cylinder pressure difference ΔP / ΔP ₀ normalized by the normalizing means and the reference charging efficiency Ce ₀ in the arbitrary reference state.
A charging efficiency calculating means for calculating, a temperature detecting means for detecting at least one of a gas temperature in a combustion chamber of the engine, a cooling water temperature of the engine, and an intake air temperature of the engine, and an output of the temperature detecting means. The filling efficiency correction means for correcting the filling efficiency Ce calculated by the filling efficiency calculation means based on the above, and the filling efficiency averaging for calculating the average filling efficiency Ce _ave by averaging the filling efficiencies corrected by the filling efficiency correction means. An engine control device comprising: means for controlling the air-fuel ratio and ignition timing of the engine based on the average charging efficiency Ce _ave obtained by the charging efficiency averaging means. 5. A pressure sensor for detecting a pressure in an engine combustion chamber, a crank angle sensor for detecting the crank angle, and a pressure difference in a cylinder in synchronization with any two crank angles during a compression stroke by the pressure sensor. Measuring means for measuring ΔP, and the in-cylinder pressure difference ΔP measured by this measuring means is normalized by the reference in-cylinder pressure difference ΔP ₀ obtained in the reference state of the engine to normalize the in-cylinder pressure difference ΔP / ΔP _0. Engine for each predetermined crank angle based on the normalization means that determines the normal pressure difference ΔP / ΔP ₀ normalized by the normalization means and the reference charging efficiency Ce ₀ in the arbitrary reference state. Charging efficiency calculation means for calculating the charging efficiency Ce of
An engine control device comprising: a charging efficiency averaging means for arithmetically averaging a predetermined number of charging efficiencies Ce calculated by the charging efficiency calculation means.