JPH09273436A - Engine control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fuel consumption, and to reduce the exhaust gas by increasing the fuel to be supplied to an engine per one combustion cycle than the fuel supplied variable corresponding to an engine load when combustion ratio value of one or plural clank angles in the normal combustion condition is larger than the reference combustion ratio. SOLUTION: At the time of operating an engine, output signal of an intake air temperature sensor 36, a heating coil type intake air variable sensor 34, a throttle open degree sensor 31, an intake pipe pressure sensor 32, a clank angle sensor 11 and an oxygen concentration sensor 25 or the like are taken into a control device 12, and the control device 12 controls so that the fuel to be supplied to an engine per one combustion cycle is increased, as engine load becomes larger. At this stage, a reference combustion ratio value as a fuel ratio value of one or plural predetermined clank angles in the normal fuel condition and a real fuel ratio are compared with each other, and in the case where the fuel ratio is larger than the reference fuel ratio, the fuel to be supplied to the engine per each one combustion cycle is controlled so as to be increased than the fuel supplied variable corresponding to the engine load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a 2-cycle spark ignition engine or a 4-cycle spark ignition engine.

[0002]

2. Description of the Related Art In a two-cycle spark ignition engine or a four-cycle spark ignition engine, there is a high possibility that abnormal combustion will occur due to an increase in the temperature inside the cylinder due to an increase in heat load due to, for example, higher rotation and higher output. If this abnormal combustion continues, the temperature inside the cylinder rises at an accelerating rate and there is a risk of engine damage.

Therefore, for example, in a high load state, the A / F
In some cases, the inside of the cylinder is enriched with the fuel to cool the inside of the cylinder to prevent abnormal combustion.

[0004]

However, since the combustion state is not grasped and controlled, it is necessary to provide a considerably large margin in the range where the fuel is cooled. For this reason, the fuel is cooled more than necessary and the fuel efficiency is deteriorated.

Further, abnormal combustion may occur even while the fuel is being cooled, and there is a problem in that it is not possible to cope with the situation at this time.

Therefore, it is necessary to have a means for grasping the combustion state to detect a sign that abnormal combustion will occur and prevent it from occurring, and if it is determined that abnormal combustion has occurred, means for avoiding danger. Will be required.

The present invention has been made in view of the above points, and prevents pre-ignition which causes ignition before ignition due to rise in temperature in the cylinder, and also appropriately processes even when ignition occurs before ignition. It is an object of the present invention to provide an engine control method capable of preventing damage to the engine.

[0008]

In order to solve the above-mentioned problems and to achieve the object, the engine control method according to the invention of claim 1 is such that the larger the engine load according to the engine load, the more 1 1 when a normal combustion state is obtained while supplying fuel per combustion cycle to the engine
Alternatively, the combustion ratio values at a plurality of predetermined crank angles are held in the memory as map data of the reference combustion ratio values corresponding to at least the load of the engine speed or the engine speed, while the actual combustion ratio values up to the one or more predetermined crank angles are stored. The combustion rate is detected, and when the combustion rate is higher than the reference combustion rate based on the comparison between the detected value of the combustion rate and the reference combustion rate, the fuel per combustion cycle to the engine is adjusted according to the engine load The feature is that the amount of fuel supplied is increased.

In this way, the actual combustion ratio up to one or more predetermined crank angles is detected, and based on the comparison between the detected combustion ratio value and the reference combustion ratio value, this combustion ratio is greater than the reference combustion ratio. In this case, the fuel amount per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of the pre-ignition is detected. Good and low exhaust gas emissions. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to the engine control method of the second aspect of the present invention, as the engine load increases according to the engine load, more fuel per combustion cycle is supplied to the engine and a normal combustion state is obtained. The combustion ratio value at one or more predetermined crank angles is held in the memory as map data of the reference combustion ratio value corresponding to at least the load of the load or the engine speed, while the actual values up to the one or more predetermined crank angles are stored. 1 combustion cycle to the engine when the combustion ratio is larger than the reference combustion ratio and the difference exceeds a predetermined amount based on the comparison between the detected value of the combustion ratio and the reference combustion ratio value. The feature is that the amount of fuel per hit is increased from the amount of fuel supply according to the engine load.

In this way, the actual combustion ratio up to one or more predetermined crank angles is detected, and based on the comparison between the detected value of this combustion ratio and the reference combustion ratio value, this combustion ratio is greater than the reference combustion ratio. When the difference exceeds a predetermined amount, the fuel amount per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Therefore, there is no waste, fuel efficiency is good, and exhaust gas emissions are low. Also, it can detect the sign of pre-ignition, so you can minimize the damage to the engine,
It is possible to prevent preignition in which ignition occurs before ignition due to an increase in the temperature inside the cylinder. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to a third aspect of the engine control method of the present invention, the larger the difference between the detected combustion ratio and the reference combustion ratio, the larger the difference. I am trying.

As described above, the larger the difference is, the more the amount is increased, depending on the magnitude of the difference between the detected combustion ratio and the reference combustion ratio.
Effectively cools fuel only when detecting the sign of pre-ignition, resulting in less waste, better fuel economy, and less emission of exhaust gas.

In the engine control method according to the fourth aspect of the present invention, even if the fuel supply amount is increased, the difference between the combustion ratio and the reference combustion ratio does not decrease, or there is a difference of a predetermined amount or more. If there is no decrease, the feature is that misfire or fuel supply is stopped.

As described above, the sign of preignition is detected, the amount of fuel is increased, and the fuel is cooled. However, if the effect is not recognized, the engine is stopped by misfiring or stopping the fuel supply. In this way, engine damage is prevented, and even when preignition occurs, it is recognized and operated, so engine reliability is improved.

According to the engine control method of the fifth aspect of the present invention, as the engine load increases according to the engine load, more fuel per combustion cycle is supplied to the engine and a normal combustion state is obtained. The crank angle value that reaches one or more predetermined combustion ratios is stored in the memory as map data of a reference crank angle value corresponding to at least the load of the engine speed or the engine speed, while the one or more predetermined combustion ratio values are stored. The actual crank angle until the engine reaches the reference crank angle is detected, and when the crank angle leads the reference crank angle based on the comparison between the detected value of the crank angle and the reference crank angle value, 1
The feature is that the amount of fuel per combustion cycle is increased from the amount of fuel supply according to the engine load.

In this way, the actual crank angle until one or more predetermined combustion ratio values is reached is detected, and this crank angle is determined as the reference value based on the comparison between the detected crank angle value and the reference crank angle value. When the engine is ahead of the crank angle, the fuel amount per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the sign of pre-ignition is detected. There is no waste, good fuel economy, and low exhaust gas emissions. Also, it can detect the sign of pre-ignition, so you can minimize the damage to the engine,
It is possible to prevent preignition in which ignition occurs before ignition due to an increase in the temperature inside the cylinder. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to the engine control method of the sixth aspect of the present invention, as the engine load increases in accordance with the engine load, more fuel per combustion cycle is supplied to the engine and a normal combustion state is obtained. The crank angle value that reaches one or a plurality of predetermined combustion ratios is stored in the memory as map data of a reference crank angle value corresponding to at least the load of the load or the engine speed, while the one or more predetermined combustion ratio values are stored. The actual crank angle until the engine reaches the engine is detected, and based on the comparison between the detected value of this crank angle and the reference crank angle value, when this crank angle leads the reference crank angle by a predetermined angle or more, The feature is that the amount of fuel per combustion cycle is increased from the amount of fuel supply according to the engine load.

In this way, the actual crank angle until one or more predetermined combustion ratio values is reached is detected, and this crank angle is determined as the reference value based on the comparison between the detected crank angle value and the reference crank angle value. When the engine is ahead of the crank angle by a predetermined angle or more, the amount of fuel per combustion cycle to the engine is increased from the amount of fuel supplied according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Depending on the state, there is no waste, good fuel economy, and low exhaust gas emissions. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

The engine control method according to a seventh aspect of the present invention is characterized in that the larger the preceding angle is, the more the amount is increased.

Thus, the larger the leading angle,
The amount is further increased, and the fuel is cooled effectively only when the sign of pre-ignition is detected, resulting in less waste, better fuel consumption, and less exhaust gas emission.

In the engine control method of the eighth aspect of the present invention, if the advance angle amount does not decrease or the advance angle amount does not decrease by a predetermined amount or more even if the fuel supply amount is increased, a misfire or a misfire may occur. Is characterized in that the fuel supply is stopped.

In this way, the sign of preignition is detected, the amount of fuel is increased, and the fuel is cooled. However, if the effect is not recognized, the engine is stopped by misfiring or stopping the fuel supply. In this way, engine damage is prevented, and even when preignition occurs, it is recognized and operated, so engine reliability is improved.

According to a ninth aspect of the engine control method of the present invention, the actual combustion ratio up to the one or more predetermined crank angles is the crank angle between the end of the exhaust stroke and the beginning of the compression stroke, and the compression ratio. The combustion pressure is detected at at least four crank angles consisting of the crank angle from the stroke start to the ignition start and the two crank angles in the period from the ignition start to the exhaust stroke start, and is calculated based on these combustion pressure data. It is characterized by doing so.

In this way, the actual combustion ratio up to one or more predetermined crank angles can be calculated appropriately based on the combustion pressure data.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION An engine control method of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram of a multi-cylinder spark ignition type 4-cycle engine to which the present invention is applied. The engine 1 includes a crankcase 2, a cylinder body 3 and a cylinder head 4 above the crankcase 2. A piston 7 is slidably mounted in the cylinder body 3 via a connecting rod 8, and the connecting rod 8 is connected to a crankshaft 9. A ring gear 10 having a predetermined number of teeth is mounted on the crankshaft 9, and a crank angle sensor 11 that also functions as an engine speed sensor for detecting a rotational position of the ring gear 10 and measuring a crank angle and an engine speed is provided. Has been. A combustion chamber 13 is formed between the cylinder head 4 and the piston 7, and an ignition plug 400 is provided so as to face the combustion chamber 13.

A combustion chamber pressure sensor 5 for detecting the combustion pressure in the combustion chamber 13 is provided on the cylinder head 4 side. A cooling water jacket 6 is formed at appropriate positions on the cylinder head 4 and the cylinder body 3. Combustion chamber 13
An exhaust passage 15 and an intake passage 16 communicate with each other, and an exhaust valve 17 and an intake valve 18 are provided at the openings thereof.
A catalyst 23 such as an exhaust gas purifying three-way catalyst is provided in the middle of an exhaust pipe 22 connected to the exhaust passage 15, and a muffler 24 is provided at an end thereof. The exhaust pipe 22 is provided with an oxygen concentration sensor (O ₂ sensor) 25 and an exhaust pipe temperature sensor 120, each of which is connected to the control device 12.

A temperature sensor 26 is attached to the cylinder head 4, and temperature information of the combustion chamber 13 is sent to the control device 12. Further, the catalyst 23 is provided with a catalyst temperature sensor 150 connected to the control device 12. The kill switch 43 of the engine 1 is further connected to the controller 12 to obtain stop information for engine drive control.

On the other hand, an intake pipe 20 is connected to the intake passage 16, and the intake pipe 20 is connected to each cylinder via an intake distribution pipe 28. An intake pipe pressure sensor 32 is attached to the intake distribution pipe 28, and intake pipe pressure information is sent to the control device 12.
The EGR pipe 15 is formed by connecting the intake distribution pipe 28 and the exhaust pipe 22.
2 are provided. The EGR pipe 152 is provided with an EGR adjustment valve 151 connected to the control device 12. An air cleaner 35 is connected to the intake distribution pipe 28 via an intake pipe 33. The air cleaner 35 is provided with an intake air temperature sensor 36, and the intake air temperature information is sent to the control device 12. An intake air amount adjuster 30 is provided in the middle of the intake pipe 33, and a throttle valve 29 is attached to the intake air amount adjuster 30.

The throttle valve 29 is provided with a throttle opening sensor 31, and this throttle opening sensor 31 is connected to the controller 12. A throttle valve bypass passage 37 is provided in the intake pipe 33 of the intake amount adjuster 30, and a bypass passage opening adjustment valve 38 is provided in the bypass passage 37. The bypass passage opening adjustment valve 38 is connected to the control device 12. In the intake pipe 33, a hot-wire intake air amount sensor 34
Is provided, and the intake air amount information is sent to the control device 12.

On the upstream side of the intake valve 18 in the intake passage 16,
An injector 105 is provided for each intake port of each cylinder. The injector 105 is connected to the control device 12, and sends a control signal of the optimum injection amount calculated according to the operating state. Fuel is sent to each injector 105 through a fuel pipe 101a connected to each cylinder. The fuel pipe 101 a is branched from the fuel distribution pipe 104, and the fuel is supplied from the fuel tank 100 to the fuel distribution pipe 104 through the fuel supply pipe 101 and further through the filter 102 by the fuel pump 103. The fuel not injected from the injector 105 is collected in the fuel tank 100 through the fuel return pipe 107. A regulator 106 is provided on the fuel return pipe 107.
Is provided to keep the fuel injection pressure constant.

FIG. 2 is a flow chart of a main routine for controlling various operating states of the engine. Each step will be described below.

Step S11: Initialization is performed, and initial values are set in each flag value and each variable value.

Step S12: Intake air temperature sensor 36
Intake air temperature information from the heat ray intake air amount sensor 34
Intake air amount information from the throttle opening sensor 31, throttle opening information from the throttle opening sensor 31, intake pipe pressure information from the intake pipe pressure sensor 32, catalyst temperature information from the catalyst temperature sensor 150, crank angle information from the crank angle sensor 11. , Temperature information from the temperature sensor 26, exhaust pipe temperature information from the exhaust pipe temperature sensor 120, oxygen concentration information from the oxygen concentration sensor 25, and oil remaining amount information from an oil sensor (not shown), and the data is stored in the memory A. Store in (i).
The engine load can be grasped as an accelerator position or a throttle opening. If the throttle opening and the engine speed are determined, the intake air amount is determined during steady operation, so the intake air amount can be directly detected and regarded as the engine load. Further, since the intake pipe negative pressure has a constant relationship with the throttle opening if the engine speed is determined, the intake pipe negative pressure can be detected and regarded as the engine load.

Step S13: O of the kill switch 43
Switch information such as N, OFF, ON / OFF of a main switch (not shown) and ON / OFF of a starter switch (not shown) is fetched and stored in the memory B (i). The kill switch 43 is an emergency stop switch and is not provided in the vehicle engine, but is provided in, for example, a small boat engine.

Step S14: The operating state is judged based on the sensor information fetched in the step 12 and the switch information fetched in the step 13, and a memory corresponding to the operating state, ... Input the value corresponding to the variable C inside.

Operating state: a constant accelerator in which the throttle opening is not less than a predetermined value, the engine speed is not less than a predetermined value, and the rate of change of the throttle opening is not more than a predetermined value. MBT (Minimum Advance Ignition for
Best Torque) It is determined to be the control state, and 1 is stored in the variable C.

Operating state: When the rate of change of the throttle opening is equal to or greater than a predetermined value, it is determined to be a transient operating state, and 2 is stored in the variable C.

Operating state: The throttle opening is below a predetermined value and the engine speed is within a predetermined range, for example, 1000 rp
In the case of m to 5000 rpm, it is determined to be the lean combustion control state, and 3 is stored in the variable C.

Operating state: When the engine is in an abnormal state such as an over-revolution in which the engine speed is equal to or higher than a predetermined limit value, or an engine temperature is overheat in which the temperature is equal to or higher than a predetermined value, it is determined to be an abnormal operation state, and 4 is stored in a variable C.

Operating state: When the engine temperature is lower than a predetermined value and the starter switch is ON, it is determined to be a cold start state, and 5 is stored in the variable C.

Operating state: When the main switch is off or the kill switch is off, it is determined that the engine is in a stop request state, and 6 is stored in the variable C.

Operating state: When the clutch is neutral, or when the engine speed is equal to or higher than a predetermined value and the idle switch is ON and the throttle valve opening is fully closed, the idle mode is determined and 7 is stored in the variable C.

Operating state: EGR control (control for recirculating a part of exhaust gas to the intake system) is determined to be EGR control mode when the switch is ON, and 8 is stored in variable C.

Operating state: When the engine temperature is equal to or higher than a predetermined value and the starter switch is ON, it is determined that the engine is normally started, and 9 is stored in the variable C.

Operating state A: When abnormal increase in combustion chamber pressure before spark ignition or abnormal change in combustion chamber pressure is detected from the combustion chamber pressure data, it is determined to be an abnormal combustion state such as pre-ignition state or knocking state. Then, 10 is stored in the variable C.

Further, with the same variable C value, the flag P = 1 is maintained and the number of times the step S14 in the main routine is checked. If R is exceeded a predetermined number of times, P = 0 is set.

When C = 1, the value of R is Rc = 1. When C = 2, the value of R is Rc = 2. When the value of C is 3, the value of R is changed to Rc = 3. Rc _{= 1} <Rc _{= 2} <Rc _{= 3} .

When the C value in the previous main routine is different from the C value this time, P = 0 is set.

Step S15: It is determined whether or not the mode operation is executed. If the variable C is 4, 6, or 9, the process proceeds to step S20. Otherwise, the process proceeds to step S20.
Move to step S16.

Step S16: Based on the value of the flag P ,
When P = 0, the target combustion ratio according to the engine speed and the load is obtained from the map data (corresponding to FIG. 5) in the memory, and the result is stored in the memory D. Also,
The basic ignition timing, the basic fuel injection start timing, and the basic fuel injection amount are also obtained from the map data similar to those shown in FIG. 5 in the memory (the values given as a function of the engine speed and the load are illustrated), and the respective memory E '(1), E'
(2) Put in E '(3). After that, P = 1 is set.
However, even if P = 0 and the variable C is 5, the target combustion ratio is obtained based on the target combustion ratio map for cold start, and the value is stored in the memory D. If P = 1
Without doing anything, the process proceeds to step S17.

The combustion ratio means the ratio of the fuel burned up to a certain crank angle to the fuel burned in one combustion cycle. Regarding the method of calculating the combustion ratio, one method is to obtain the combustion chamber pressure data at a plurality of predetermined points in one combustion cycle by a linear approximation formula, and the other is to calculate the heat generation amount from the sampled pressure value. Is calculated by a thermodynamic equation to obtain the combustion ratio up to one or more predetermined crank angles (for example, top dead center). Both methods gave calculation results very close to the true value. in this case,
The combustion chamber pressure data is obtained by detecting the combustion chamber pressure at one or a plurality of crank angles in the first period from the end of the exhaust stroke to the beginning of the compression stroke. In this case, the crank angle from the end of the exhaust stroke to the beginning of the compression stroke is the crank angle within the range where the pressure in the combustion chamber is the lowest and approaches the atmospheric pressure. A point or its vicinity. That is, in a 4-cycle engine,
As shown in FIG. 6, the combustion gas in the combustion chamber is discharged by the exhaust stroke from the bottom dead center after the explosion, and as the pressure approaches the top dead center, the pressure in the combustion chamber decreases and approaches the atmospheric pressure. In the intake stroke after top dead center, a state close to atmospheric pressure is maintained due to the introduction of fresh air,
The pressure is gradually increased from the compression stroke after the bottom dead center which is started when the exhaust valve 17 is closed after the intake stroke. The pressure inside the combustion chamber is detected at one point within the range where the pressure inside the combustion chamber decreases and approaches the atmospheric pressure. Crank angle a in Fig. 6
0 is taken to BDC, but if it is the beginning of the compression stroke,
It may be after BDC. Of course, the crank angle during the intake stroke before BDC may be used. On the other hand, in the two-cycle engine, as shown in FIG. 14, when the piston is lowered and the pressure is reduced after the explosion and the exhaust port is opened, the pressure in the combustion chamber is further reduced accordingly, and when the scavenging port is opened, fresh air is released from the crank chamber. As it is introduced, it approaches atmospheric pressure. When the piston rises from the bottom dead center with the exhaust port open, the scavenging port closes and the exhaust port opens, the compression starts and the pressure gradually increases. That is, from the end of the exhaust stroke to the beginning of the compression stroke, after the exhaust port is opened and the exhaust port is open after the start of exhaust, the scavenging port is opened and intake is started, and then the exhaust port is closed. This is the period until the compression starts. In FIG. 14, the crank angle a0 is taken as BDC.

Spark ignition is performed before or after top dead center after compression. (Spark ignition is started at the crank angles shown by arrows and S in FIGS. 6 and 14, respectively.) Spark ignition is started, and ignition is started with a slight delay and combustion is started. The ignition start referred to in each claim is the moment when this ignition combustion is started. That is, the crank angle (FIG. 6, FIG. 1) in the second period, which is the period from the start of the compression stroke to the start of ignition and combustion.
In both Nos. 4 and 4, the pressure in the smelting chamber is detected at the crank angle a1). After this, the third period, which is the period from the start of ignition (start of ignition and combustion) to the start of the exhaust stroke during the explosive combustion stroke
Of two crank angles (for example, crank angle a2a3 or crank angle a in FIGS. 6 and 14)
2, a4, or crank angles a3, a4, crank angles a2, a5, crank angles a3, a5, or crank angles a4, a5), the pressure in the combustion chamber is detected. It is desirable that one of the two crank angles within this period be before the crank angle at which the maximum combustion pressure is reached. Further, when the pressure in the combustion chamber is detected at four or more crank angles, for example, at five or more crank angles referred to in each claim, the number of pressure measurement crank angle points in the first or second period is increased. May be. Further, preferably, the pressure may be detected at three or more crank angles within the third period as in the embodiment of FIGS. 6 and 14. In a diesel engine, fuel injection into the combustion chamber before or after top dead center after compression is started, and after a short delay, combustion starts due to spontaneous ignition. That is, in the diesel engine, the ignition start described in each claim means the moment when the spontaneous ignition is started. Note that the ignition delay from the start of fuel injection to the start of spontaneous ignition is obtained in advance as data based on the engine speed or the load, and this is factored in to calculate the pressure measurement crank angle within the second period and the pressure crank within the third period. The pressure of the combustion chamber is measured by storing the corner points in the memory as data based on the engine speed or the load.

One point for the first period and one for the second period
Point, the combustion chamber pressure at a crank angle of at least 4 points in total of 2 points in the third period is detected, and the combustion ratio is calculated from this by a linear approximation. This approximation formula is combustion rate qx = a + b1 * (P1-P0) + b2 * (P
2-P0) + ... + bn * (Pn-P0).

As can be seen from the above equation, qx is obtained by subtracting the reference pressure P0 from each of the pressure data P1 to Pn,
Multiplying the constants b1 to bn by a preset constant a
It is expressed by adding.

Similarly, Pmi is also expressed by subtracting the reference pressure P0 from the pressure data P1 to Pn, multiplying the preset constants C1 to Cn, and adding the preset constants.

Here, P0 is the combustion chamber pressure at the point of the atmospheric pressure level (for example, the crank angle near BDC as described above), and each pressure value of P1 to Pn is used to correct the offset voltage due to the drift of the sensor. Drawn from. Further, P1 is the combustion pressure at the crank angle a1 in the first period, and P2 is the combustion chamber pressure at the crank angle a2 in the second period. P3 to Pn are crank angles a3 to an (n = 5 in this embodiment) in the third period.

By such a simple first-order approximation calculation, the combustion ratio up to a predetermined crank angle after ignition can be calculated to be exactly the same as the actual value in a short time. Therefore,
By controlling the ignition timing and the air-fuel ratio of the engine by using such a combustion ratio, it is possible to efficiently take out the energy due to combustion and improve the responsiveness, for example, when performing lean burn control or EGR control. The output fluctuation can be suppressed by accurately following the operating state. Further, it is possible to prevent the generation of NOx due to the rapid progress of combustion. In the second qx calculation method, the amount of heat generated between two pressure measurement points (crank angle) is ΔP for the differential pressure at both pressure measurement points, ΔV for the combustion chamber volume difference, and The front pressure value and the combustion chamber volume value are P, V, and A.
Is heat equivalent, K is specific heat ratio, R is average gas constant, P0 is BD
Assuming the pressure value at C, the heat generation amount Qx = A / (K-1)
* ((K + 1) / 2 * ΔP * ΔV + K * (P-P0) *
ΔV + V * ΔP) can be obtained.

The combustion ratio up to the predetermined pressure measurement point is
The crank angle at which combustion is almost completed is selected as the pressure measurement point, and the crank angle near ignition is similarly selected as the pressure measurement point, and the heat generation amount Qx is measured at each pressure measurement point measured during that time. Is the sum of the calculated values of the above, and is the sum of the calculated values of Qx from the first pressure measurement point to the predetermined pressure measurement point (predetermined crank angle). .

That is, the combustion ratio qx = heat quantity burned up to an arbitrary crank angle / total heat quantity × 100 (%) = (Q1
+ Q2 + ... + Qx) / (Q1 + Q2 + ... + Q
n) × 100.

The combustion chamber pressure at a plurality of predetermined crank angles is measured by the above calculation method (in step S112 of FIG. 3), and the combustion ratio up to the predetermined crank angle is accurately calculated based on the data. It is possible (at step S201 of FIG. 7). By controlling the engine using this combustion ratio, stable output and engine rotation can be obtained.

Step S17: An injection amount correction calculation for fuel injection is performed based on the intake air temperature information and the intake pipe negative pressure information. That is, when the intake air temperature is high, the air density is low, and the air flow rate is substantially reduced. Therefore, the air-fuel ratio in the combustion chamber becomes low. Therefore, a correction amount for reducing the fuel injection amount is calculated.

Step S18: The basic fuel injection start, the basic fuel injection amount, and the basic ignition timing according to the engine load and the engine speed are obtained in step S16 and are included in E '(i). Based on this, the fuel injection correction amount and the ignition timing correction amount are calculated according to the correction amount calculated in step S17 and the information stored in the memory A (i), and the control amount is calculated in addition to the reference values. The control amount is set to the memory E (1) for the ignition start timing, the memory E (2) for the ignition period, and the injection start timing and the injection end timing are set to F when P = 1.
When (3), F (4) and P = 0, the injection start timing and the injection end timing are put into E (3) and E (4).

This is input to the memory E (i). Similarly, the control amounts of the servo motor group and the solenoid valve group are calculated according to the information stored in the memory A (i) and are stored in the memory G (i).

Step S19: The actuators such as the servo motor group and the solenoid valve group are driven and controlled according to the control amount of the memory G (i).

Step S20: The engine stop request is determined, and if the variable C is 6, the process proceeds to step S21, and if not, the process proceeds to step S22.

Step S21: Memory E (i) i = 1 to
Stop data is set to 4 to 0, or the spark plug 400 is misfired.

Step S22: It is judged whether or not the variable C is 9, and if the variable C is 9 and the normal engine is started, the process proceeds to step S23, and if not, the process proceeds to step S25.

Step S23: The memory F (i) is set with data stored in advance for starting, that is, data for retarding the ignition timing and slightly increasing the fuel injection amount.

Step S24: The starting motor is driven.

Step S25: In the case where the variable C is 4, the data corresponding to the abnormality content is stored in the memory F (i), for example, the data for increasing the fuel injection amount while reducing the throttle opening in the case of over-revolution and misfire for over-heating. Set.

Next, the interrupt routine of FIG. 3 will be described. This interrupt routine is executed by interrupting the main routine when a crank signal of a predetermined angle is input.

Step S111: The timer is set so that the interrupt routine is executed at every predetermined crank angle, that is, the interrupt is generated at the next crank angle.

Step S112: The pressure data of the crank angle at which the interruption has occurred is fetched and stored in the memory.

Step S113: When the pressure data of all crank angles are taken into the memory, the process proceeds to step S114.

Steps S114 to S115: Variable C is 1
It is checked whether or not 0, and if C = 10, it is determined that abnormal combustion has occurred, and the abnormal combustion prevention routine of step S115 is performed and the routine returns. If not, the process proceeds to step S116.

Step S116: Whether C = 2 is checked to determine whether it is in a transient state, and if so, a transient control routine is executed in step S116a to correct the ignition timing and A / F and return. To do. If not, the process proceeds to step S117.

Step S117: Whether C = 5 is checked to determine whether it is a cold start. If it is, a cold start control routine is executed in step S117a, the ignition timing is corrected, and the routine returns. If not, the process proceeds to step S118.

Step S118: Whether C = 8 is checked to determine whether the mode is the EGR control mode, and if so, the EGR control routine is executed in step S118a to correct the EGR rate and the ignition timing, and the process returns. . If not, the process proceeds to step S119.

Step S119: It is determined whether or not C = 3 is checked to determine whether or not the lean combustion mode is set. If this is the case, the lean burn control routine is executed at step S119a to correct the A / F and ignition timing. And return. If not, the process proceeds to step S120.

Step S120: Whether C = 7 is checked to determine whether it is in the idling mode. If so, an idling control routine is executed in step S120a to correct the A / F and ignition timing and then return. . If not, the MBT control routine is executed in step S121 to correct the ignition timing and the process returns.

Next, the interrupt routine of FIG. 4 will be described. This interrupt routine is executed by interrupting the main routine when the reference crank signal is input.

Step S121: Since this interrupt routine is executed once at the engine rotation and the predetermined crank angle, the cycle is measured.

Step S122: The engine speed is calculated.

Step S123: Memory F (i), i =
Based on the control data of 1 to 4, the ignition start timing, the ignition end timing, the injection start timing, and the injection end timing are set in the timer. The timer activates the ignition device and the injection device at the set timing.

Next, the calculation of the target combustion ratio described with reference to FIGS. 2 and 3 will be described in detail.

FIG. 5 is a map showing a reference combustion ratio or a limit combustion ratio depending on the engine speed and the load. One or a plurality of predetermined crank angles, for example, a standard combustion rate during normal combustion up to top dead center TDC, or a critical combustion rate during a precursory state during abnormal combustion that is greater than the reference combustion rate during normal combustion is mapped. It is obtained from the data and stored in the storage device of the control device 12. Load (Lx)
And the reference combustion ratio or the limit combustion ratio is determined by the engine speed (Rx). The reference combustion rate or the limit combustion rate under predetermined operating conditions (Lx, Rx) is FMB ₀ (Lxi, Rxi), i = 1 to
It is calculated as n.

The reference combustion ratio or the limit combustion ratio data for a plurality of crank angles may be provided as the reference combustion ratio or the limit combustion ratio data according to the operating condition. For example, a predetermined crank angle at the initial stage of combustion, The reference combustion rate or the limit combustion rate data of a predetermined crank angle in the latter stage of combustion is provided. Further, as the crank angle value data for reaching the predetermined combustion ratio when the normal combustion state is obtained, crank angle value data for reaching a plurality of combustion ratios may be provided.

FIG. 6 is a graph of combustion chamber pressure for one cycle of combustion in a four-cycle engine. The horizontal axis is the crank angle,
The vertical axis represents the combustion pressure. The crank angle is a0
The combustion pressures P0 to P5 at the six points a5 are detected, and the combustion ratio is calculated based on these pressure values. a0 is the bottom dead center position (BDC) where the suction shifts to the compression shift, which is a state close to the atmospheric pressure. a1 is after compression start but before spark ignition,
a2 is a crank angle after reaching the top dead center (TDC) after spark ignition at S. The four points a3 to a5 are crank angles in the explosion stroke after top dead center. The combustion ratio is calculated based on the pressure data at these points. In the case of a diesel engine that does not perform spark ignition, F
Like I, the fuel is injected near the top dead center. Spontaneous ignition occurs after a delay corresponding to the crank angle d after the start of injection. The crank angle for spontaneous ignition is S. Instead of controlling the ignition timing in the ignition spark engine, in the present diesel engine, the control of the fuel injection timing is performed based on the measured combustion ratio or the measured crank angle based on the difference between the target combustion ratio and the target crank angle, respectively. The injection start timing is advanced / retarded, and the injection end timing is controlled so as to secure a predetermined injection amount.

Next, the control of the combustion ratio based on the calculation of the combustion ratio described in FIGS. 2 and 3 will be described in detail.

The correction calculation in step S17 of FIG. 2 is executed as in the flow chart of the correction calculation of FIG. That is, when the variable C = 2, step S17 is executed, the fuel injection amount correction calculation for atmospheric pressure correction is executed based on the intake air temperature information and the intake pipe negative pressure information in step S17a, and the transient control state is executed in step S17b. Variable STA
A TE tick is performed and the variable of the transient control state is STA.
In the steady state of TE = 0, the transient correction data is cleared in step S17c. If it is not in the steady state, the process proceeds to step S17d, and the variable in the transient control state is STAT.
The transient state of E = 1 is checked for the first execution state. If the first execution state is checked, the process proceeds to step S17e. Initial correction is executed in step S17e, and timing correction is performed at the fuel injection data increase correction point during acceleration and deceleration. In step S17f, the variable of the transient control state is ST.
When ATE = 2, the transient control is initially executed.

Next, an abnormal combustion prevention routine is shown in FIG. This abnormal combustion prevention routine is executed every cycle after the abnormality determination.

Step S251: Actual combustion ratio FMB
(Θ) is compared with the abnormality determination combustion rate FMBMAX, and if they are equal or the actual combustion rate is greater, step S252.
Move on to If not, the process proceeds to step S255.

Step S252: The fuel cooling correction value CFTX up to the previous time is added with the fuel cooling correction step CFTR on the increasing side to obtain the fuel cooling correction value CFTX, and the routine proceeds to step S253.

Step S253: Fuel cooling correction value CFT
X is compared with the maximum limit value CFTXMX of the fuel cooling correction, and if the fuel cooling correction value CFTX is larger, the process proceeds to step S254a. If not, step S
Move to 254b.

Step S254a: Combustion state variable DFG
F is set to 2 (fuel cut, ignition cut request) and the process returns.

Step S254b: Combustion state variable DFG
Set F to 1 (abnormal combustion state) and return.

Step S255: The fuel cooling correction value CFTX on the amount reducing side is subtracted from the fuel cooling correction value CFTX up to the previous time to obtain the fuel cooling correction value CFTX, and the routine proceeds to step S256.

Step S256: Fuel cooling correction value CFT
It is judged whether X is smaller than 0 (normal state), and 0
If it is smaller than (normal state), the process proceeds to step S257. If not, the process proceeds to step S258.

Step S257: Fuel cooling correction value CFT
X is set to 0 (normal state) and the process proceeds to step S258. Step S258: Set the combustion state variable DEGF to 0 (normal state) and return.

In this abnormal combustion prevention control, any one of the following control is performed.

First, the abnormal combustion prevention control supplies more fuel per combustion cycle to the engine as the engine load increases in accordance with the engine load, and at least one predetermined number of times when a normal combustion state is obtained. The combustion ratio value at the crank angle is stored in the memory as map data of the reference combustion ratio value corresponding to at least the load of the engine speed or the load, while the actual combustion ratio up to one or more predetermined crank angles is detected. , Based on the comparison between the detected value of the combustion ratio and the reference combustion ratio value, when the combustion ratio is higher than the reference combustion ratio, 1 is given to the engine.
The fuel per combustion cycle is increased from the fuel supply amount according to the engine load. In this way, the actual combustion ratio up to one or more predetermined crank angles is detected, and based on the comparison between the detected value of this combustion ratio and the reference combustion ratio value, when this combustion ratio is greater than the reference combustion ratio, In order to increase the fuel per combustion cycle to the engine from the fuel supply amount according to the engine load, the fuel is cooled only when the precursor of pre-ignition is detected, there is no waste depending on the operating condition, and fuel efficiency is good. Emission of exhaust gas is also small. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

Further, the abnormal combustion prevention control supplies more fuel per combustion cycle to the engine as the engine load increases in accordance with the engine load, and at least one predetermined value when a normal combustion state is obtained. The combustion ratio value at the crank angle is stored in the memory as map data of the reference combustion ratio value corresponding to at least the load of the engine speed or the load, while the actual combustion ratio up to one or more predetermined crank angles is detected. , Based on the comparison between the detected value of the combustion ratio and the reference combustion ratio value, when the combustion ratio is larger than the reference combustion ratio and the difference exceeds a predetermined amount, the fuel per combustion cycle is applied to the engine as engine load. The fuel supply amount is increased according to. In this way, the actual combustion ratio up to one or more predetermined crank angles is detected, and based on the comparison between the detected value of this combustion ratio and the reference combustion ratio value, this combustion ratio is greater than the reference combustion ratio and When the difference exceeds a certain amount, 1 to the engine
Since the fuel amount per combustion cycle is increased from the fuel supply amount according to the engine load, the fuel is cooled only when the precursor of pre-ignition is detected. Few. Also,
Since the sign of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to an increase in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

Further, in the abnormal combustion prevention control or in the abnormal combustion prevention control, the larger the difference is, the more the amount is increased according to the magnitude of the difference between the combustion ratio and the reference combustion ratio.
Thus, depending on the magnitude of the difference between the combustion ratio and the reference combustion ratio, the larger the difference, the more the amount is increased, and the fuel is cooled effectively only when the precursor of preignition is detected.
It is less wasteful, has better fuel economy, and emits less exhaust gas.

Further, in the abnormal combustion prevention control, in the abnormal combustion prevention control or, even if the fuel supply amount is increased, the difference between the combustion ratio and the reference combustion ratio does not decrease, or the difference of a predetermined amount or more decreases. If there is not, perform a misfire or stop the fuel supply. In this way, the sign of preignition is detected, the amount of fuel is increased, and the fuel is cooled, but if the effect of this is not recognized, misfire or fuel supply is stopped to stop the engine. Engine damage is prevented, and even when pre-ignition occurs, it is recognized and operated, improving engine reliability.

In the abnormal combustion prevention control, as the engine load increases in accordance with the engine load, more fuel per combustion cycle is supplied to the engine, and one or a plurality of predetermined values for obtaining a normal combustion state are provided. The crank angle value that reaches the combustion ratio is stored in the memory as map data of the reference crank angle value corresponding to at least the load of the engine speed or the load, while the actual value until one or more predetermined combustion ratio values is reached. The crank angle of the engine is detected, and based on the comparison between the detected value of this crank angle and the reference crank angle value, when this crank angle is ahead of the reference crank angle, the fuel per combustion cycle to the engine The fuel supply amount is increased according to.
In this way, the actual crank angle until one or more predetermined combustion ratio values is reached is detected, and based on the comparison between the detected value of this crank angle and the reference crank angle value, this crank angle is When preceding, the fuel per combustion cycle to the engine is increased more than the fuel supply amount according to the engine load. Therefore, the fuel is cooled only when the sign of pre-ignition is detected, and there is a waste depending on the operating condition. Fuel efficiency and exhaust gas emissions are low. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

In the abnormal combustion prevention control, as the engine load increases in accordance with the engine load, more fuel per combustion cycle is supplied to the engine, and one or a plurality of predetermined values for obtaining a normal combustion state are provided. The crank angle value that reaches the combustion ratio is stored in the memory as map data of the reference crank angle value corresponding to at least the load of the load or the engine speed, while the actual value until one or more predetermined combustion ratio values is reached. When the crank angle is ahead of the reference crank angle by a predetermined angle or more based on the comparison between the detected crank angle and the reference crank angle value, the fuel per combustion cycle to the engine Is increased from the fuel supply amount according to the engine load. In this way, the actual crank angle until one or more predetermined combustion ratio values is reached is detected, and based on the comparison between the detected value of this crank angle and the reference crank angle value, this crank angle is When the vehicle is ahead by a predetermined angle or more, the fuel amount per combustion cycle to the engine is increased from the fuel supply amount according to the engine load. Therefore, the fuel is cooled only when the sign of pre-ignition is detected, and it depends on the operating condition. There is no waste, good fuel economy, and low exhaust gas emissions. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

In the abnormal combustion prevention control, the abnormal combustion prevention control is such that the larger the preceding angle is, the more the amount is increased. Thus, the leading angle is
The larger the amount, the more the amount is increased, and the fuel is effectively cooled only when the sign of pre-ignition is detected, resulting in less waste, better fuel consumption, and less emission of exhaust gas.

Further, in the abnormal combustion prevention control, in the abnormal combustion prevention control or after, if the advance angle amount is not decreased or the advance angle amount is not decreased more than a predetermined amount even if the fuel supply amount is increased, the misfire is caused. Alternatively, the fuel supply is stopped. In this way, detecting the sign of pre-ignition,
The amount of fuel is increased to cool the fuel, but if this effect is not observed, misfire or stop the fuel supply to stop the engine to prevent engine damage and preignition occurs. Even if it happens, it recognizes this and operates it, improving the reliability of the engine.

In the abnormal combustion prevention control and the abnormal combustion prevention control, the actual combustion ratio up to one or more predetermined crank angles is the crank angle from the end of the exhaust stroke to the beginning of the compression stroke. Combustion pressure is detected at at least four crank angles consisting of the crank angle from the compression stroke start to ignition start and the two crank angles in the period from ignition start to exhaust stroke start, and is calculated based on these combustion pressure data To do. In this way, the actual combustion ratio up to the predetermined crank angle can be appropriately calculated based on the combustion pressure data.

FIG. 9 is a diagram showing the relationship between the crank angle and the combustion ratio FMB when the ignition timing is 20 degrees BTDC. The predetermined crank angle corresponding to abnormal combustion prevention control or
The predetermined combustion ratio corresponding to the abnormal combustion prevention control or is indicated by A. 9A is 9 when play ignition occurs
B indicates a high temperature inside the cylinder and a sign of preignition, and 9C indicates a normal time.

In the abnormal combustion prevention control or, the actually measured combustion ratio at one or more predetermined crank angles (for example, B) is larger than the normal combustion ratio a3, a1, a.
If it is 2, the fuel supply amount is increased.

In the abnormal combustion prevention control or, if the actually measured crank angle reaching one or more predetermined combustion ratios (for example, A) is ahead of the normal crank angle b3 by b1 and b2, the fuel supply amount is increased. To do.

FIG. 10 is a graph showing the relationship between crank angle and in-cylinder gas temperature. 10A indicates a preignition occurrence, 10B indicates a high temperature inside the cylinder, a preignition of preignition, and 10C indicates a normal time. At the time of preignition of 10A and at the time of high temperature in the cylinder of 10B, when the preignition of preignition occurs, the gas temperature in the cylinder is higher than that at the normal time of 10C, so increase the fuel supply amount by predicting the temperature rise in the cylinder. Cool down the fuel with.

FIG. 11 is a graph showing the relationship between crank angle and cylinder pressure. Reference numeral 11A indicates a preignition occurrence time, 11B indicates a high temperature inside the cylinder, and a preignition time of preignition, and 11C indicates a normal time. At the time of preignition of 10A, at the time of high temperature in the cylinder of 10B, when the preignition of preignition is performed, the pressure in the cylinder is higher than the normal pressure of 10C
By predicting the pressure rise in the cylinder and increasing the fuel supply amount, the fuel is cooled and reduced.

FIG. 12 is a map of the reference crank angle during normal combustion or the limit crank angle in the precursory state of abnormal combustion preceding the reference crank angle during normal combustion.

That is, in FIG. 12, the horizontal axis shows the load (L), and the vertical axis shows the reference crank angle or the limit crank angle CRA that should reach the predetermined combustion ratio.
When the reference crank angle that should reach 0%, 70%, 80%, or the limit crank angle CRA ₀ (Rxi, Lxi) is the actual engine speed rpm (Rx) and the actual engine load (Lx) Is calculated from the map.

FIG. 13 is a block diagram of a two-cycle engine to which the present invention is applied. Similar to the four-stroke engine of FIG. 1, the connecting rod 246 is connected to the crankshaft 241.
A combustion chamber 2 is provided between the piston at the tip of the cylinder and the cylinder head.
48 are formed. The crankcase 300 is provided with an engine speed sensor 267 and a crank angle detection sensor 268 for detecting a mark of a ring gear mounted on the crankshaft 241 to detect a reference signal and a crank angle. Further, the crankcase 300 is provided with a crank chamber pressure sensor 210. Crank chamber 301
Is sent from the intake manifold via a reed valve 228. Air is sent from the air cleaner 231 to the intake manifold via the throttle valve 204. An intake pipe pressure sensor 211 is attached to an intake passage downstream of the throttle valve that communicates with the intake manifold. The throttle valve 204 is operated by a grip 206 connected by a wire 205 via a throttle pulley 203. Grip 206
Is attached to an end portion of a steering handle 207, and an accelerator position sensor 202 is provided at the base portion thereof. 21
Reference numeral 2 is a throttle opening sensor.

A scavenging port 229 opens in the cylinder,
Combustion chamber 2 through a scavenging passage 252 at a predetermined position of the piston
48 and the crank chamber 301 are connected. Further, an exhaust port 254 is opened in the cylinder, and an exhaust passage 253 communicates with it. An exhaust timing variable valve 264 is mounted on the exhaust passage wall near the exhaust port. The variable valve 264 is driven by an actuator 265 composed of a servo motor or the like, and the opening position of the exhaust port is changed to adjust the exhaust timing. An exhaust pipe pressure sensor 213 and an exhaust pipe temperature sensor 223 are provided in the exhaust pipe forming the exhaust passage 253. An exhaust passage valve 281 is provided in the exhaust passage and is driven by an actuator 282 including a servomotor or the like. The exhaust passage valve 281 is throttled in the low speed range to prevent blow-through and to stabilize the rotation.

A knock sensor 201 is mounted on the cylinder head, and a spark plug 400 and a combustion chamber pressure sensor 200 are mounted facing the combustion chamber. The spark plug is connected to the ignition control device 256. An injector 208 is attached to the side wall of the cylinder. Injector 2
Fuel is sent to 08 through a fuel delivery pipe 209.

Further, a combustion gas chamber 279 is formed in the cylinder block so as to communicate with a portion closer to the cylinder head than the exhaust boat opening of the cylinder bore and an intermediate portion of the exhaust port through a communication hole 278. This communication hole is set so that the combustion gas containing almost no blow-through gas is introduced into the combustion gas chamber in the explosion stroke.
An O ₂ sensor 277 for detecting the oxygen concentration in the combustion gas is installed in the combustion gas chamber. A check valve (not shown) is arranged at the inlet of the combustion gas chamber and the outlet of the exhaust port to prevent the flow in the opposite direction.

The drive of such an engine is controlled by a control device 257 having a CPU 271. On the input side of the control device 257, the above-mentioned combustion chamber pressure sensor 200,
Knock sensor 201, accelerator position sensor 202, crank chamber pressure sensor 210, intake pipe pressure sensor 211, throttle opening sensor 212, exhaust pipe pressure sensor 213, crank angle detection sensor 258, engine speed sensor 267 and O ₂ sensor 277 are provided. Connected. In addition, the control device 25
An injector 208, an exhaust timing adjusting valve actuator 265, and an exhaust valve actuator 282 are connected to the output side of 7.

FIG. 14 is a graph of the combustion chamber pressure similar to that of FIG. 6 and the above-mentioned four-cycle engine for showing the combustion pressure data detection points for measuring the combustion ratio of the two-cycle engine. As mentioned above, combustion chamber pressure data is sampled at 6 crank angles. In the drawing, the range of A is the crank angle region where the exhaust port is open, and the range of B is the crank angle region where the scavenging port is open. The method of calculating and calculating each crank angle (a0 to a5) is substantially the same as that of the above-described 4-cycle engine, and in step S113 of the interrupt routine of FIG.
The combustion pressures P0 to P5 at the six points a0 to a5 where the crank angle is shown are detected, and the combustion ratio is calculated based on these pressure values. Each of the embodiments of the present invention can also be adopted in which combustion is supplied by a vaporizer.

[0125]

As described above, according to the invention of claim 1, the combustion ratio value at one or more predetermined crank angles when a normal combustion state is obtained corresponds to at least the load of the load or the engine speed. While holding in the memory as the map data of the reference combustion ratio value, the actual combustion ratio up to one or more predetermined crank angles is detected, and based on the comparison between the detected combustion ratio value and the reference combustion ratio value, When the combustion ratio is higher than the standard combustion ratio, the fuel per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Therefore, there is no waste, fuel efficiency is good, and exhaust gas emissions are low.
Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to the second aspect of the present invention, the map of the combustion ratio value at one or a plurality of predetermined crank angles when the normal combustion state is obtained is a map of the reference combustion ratio value corresponding to at least the load or the engine speed. While holding it as data in the memory, the actual combustion ratio up to one or more specified crank angles is detected, and based on the comparison between the detected combustion ratio value and the reference combustion ratio value, this combustion ratio is higher than the reference combustion ratio. When the difference is large and exceeds a predetermined amount, the fuel per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Depending on the state, there is no waste, good fuel economy, and low exhaust gas emissions. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to the third aspect of the present invention, the larger the difference is, the more the amount is increased according to the magnitude of the difference between the detected combustion ratio and the reference combustion ratio, and the effective amount is obtained only when the precursor of preignition is detected. Fuel is cooled, less waste, better fuel economy, and less exhaust gas is emitted.

According to the fourth aspect of the present invention, if the difference between the combustion ratio and the reference combustion ratio does not decrease even if the fuel supply amount is increased, or if there is no decrease of a predetermined amount or more, then misfire or fuel The supply is stopped, the sign of preignition is detected, the amount of fuel is increased, and the fuel is cooled, but if the effect is not recognized, the engine is stopped by misfiring or stopping the fuel supply. In this way, engine damage is prevented, and even when preignition occurs, it is recognized and operated, so engine reliability is improved.

According to the fifth aspect of the present invention, the crank angle value that reaches one or more predetermined combustion ratios when a normal combustion state is obtained is defined as a reference crank angle value corresponding to at least the load or the engine speed. The actual crank angle until one or more predetermined combustion ratio values is reached is stored in the memory as map data of the crank angle, and based on the comparison between the detected crank angle value and the reference crank angle value, this crank angle is detected. When the angle is ahead of the reference crank angle, the fuel per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Depending on the state, there is no waste, good fuel economy, and low exhaust gas emissions. Also, it can detect the sign of pre-ignition, so you can minimize the damage to the engine,
It is possible to prevent preignition in which ignition occurs before ignition due to an increase in the temperature inside the cylinder. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

According to a sixth aspect of the present invention, the crank angle value that reaches one or more predetermined combustion ratios when a normal combustion state is obtained is a reference crank angle value corresponding to at least the load or the engine speed. The actual crank angle until one or more predetermined combustion ratio values is reached is stored in the memory as map data of the crank angle, and the crank angle is detected based on the comparison between the detected crank angle value and the reference crank angle value. When the angle is ahead of the reference crank angle by a predetermined angle or more, the fuel per combustion cycle to the engine is increased from the fuel supply amount according to the engine load, and the fuel is cooled only when the precursor of preignition is detected. Therefore, there is no waste according to the driving condition, fuel consumption is good, and exhaust gas is also emitted little. Further, since the precursor of pre-ignition can be detected, damage to the engine can be minimized, and pre-ignition in which ignition occurs before ignition due to rise in temperature in the cylinder can be prevented. Moreover, since the fuel is cooled by predicting the temperature increase in the cylinder, knocking can be suppressed.

In the invention according to claim 7, the preceding angle is
The greater the amount, the greater the angle ahead, the greater the amount, the more effective the fuel is cooled only when the precursor of pre-ignition is detected, resulting in less waste, better fuel consumption, and exhaust gas emission. Also few.

According to the eighth aspect of the present invention, if the advance angle amount does not decrease or the advance angle amount does not decrease more than a predetermined amount even if the fuel supply amount is increased, the misfire or the fuel supply is stopped. Conduct a preignition sign to detect the sign of preignition and increase the amount of fuel to cool the fuel, but if the effect is not recognized, stop the engine by stopping misfire or stop the fuel supply. To prevent damage
Even when pre-ignition occurs, it recognizes and operates it, which improves engine reliability.

According to the ninth aspect of the present invention, the actual combustion ratio up to one or more predetermined crank angles can be appropriately calculated based on the combustion pressure data.

[Brief description of drawings]

1 is a multiple cylinder spark ignition type 4 to which the present invention is applied;
It is a block diagram of a cycle engine.

FIG. 2 is a flowchart of a main routine for controlling various operating states of the engine.

FIG. 3 is a diagram showing an interrupt routine.

FIG. 4 is a diagram showing an interrupt routine.

FIG. 5 is a map diagram for obtaining a reference combustion ratio or a limit combustion ratio according to an engine speed and a load.

FIG. 6 is a graph of combustion chamber pressure for one cycle of combustion in a four-cycle engine.

FIG. 7 is a flowchart of correction calculation.

FIG. 8 is an abnormal combustion prevention routine.

FIG. 9 is a diagram showing a relationship between a crank angle and a combustion ratio FMB at an ignition timing of 20 ° BTDC.

FIG. 10 is a graph showing the relationship between crank angle and in-cylinder gas temperature.

FIG. 11 is a graph showing the relationship between crank angle and cylinder pressure.

FIG. 12 is a map of a reference crank angle during normal combustion or a limit crank angle in a precursory state of abnormal combustion preceding the reference crank angle during normal combustion.

FIG. 13 is a configuration diagram of a two-cycle engine to which the present invention is applied.

FIG. 14 is a graph of combustion chamber pressure, similar to FIG. 6 of the above-described four-cycle engine, for showing the combustion pressure data detection points for measuring the axial torque and the combustion ratio of the two-cycle engine.

[Explanation of symbols]

1 Engine 9 Crankshaft 10 Ring Gear 11 Crank Angle Sensor 12 Control Device 13 Combustion Chamber 25 Oxygen Concentration Sensor (O ₂ Sensor) 26 Temperature Sensor 31 Throttle Opening Sensor 32 Intake Pipe Pressure Sensor 34 Hot Wire Intake Air Volume Sensor 36 Intake Air Temperature Sensor 105 Injector 106 Regulator 120 Exhaust pipe temperature sensor 150 Catalyst temperature sensor

Claims (9)

[Claims] 1. A combustion ratio value at one or a plurality of predetermined crank angles when a normal combustion state is obtained while supplying more fuel per combustion cycle to the engine as the engine load increases according to the engine load. Is stored in the memory as map data of a reference combustion rate value corresponding to at least the load of the engine speed or the engine speed, while the actual combustion rate up to one or more predetermined crank angles is detected, and Based on the comparison between the detected value and the reference combustion ratio value, when this combustion ratio is higher than the reference combustion ratio, the fuel per combustion cycle to the engine is increased from the fuel supply amount according to the engine load. A method for controlling an engine characterized by. 2. A combustion ratio value at one or a plurality of predetermined crank angles when a normal combustion state is obtained while supplying more fuel per combustion cycle to the engine as the engine load increases according to the engine load. Is stored in the memory as map data of a reference combustion rate value corresponding to at least the load of the engine speed or the engine speed, while the actual combustion rate up to one or more predetermined crank angles is detected, and Based on the comparison between the detected value and the reference combustion ratio value, when this combustion ratio is larger than the reference combustion ratio and the difference exceeds a predetermined amount, the fuel per combustion cycle is supplied to the engine according to the engine load. A method for controlling an engine, characterized in that the amount is increased more than the amount. 3. The method according to claim 1, wherein the larger the difference is, the more the amount is increased according to the magnitude of the difference between the detected combustion ratio and the reference combustion ratio. Engine control method. 4. If the difference between the combustion ratio and the reference combustion ratio does not decrease or the difference of a predetermined amount or more does not decrease even if the fuel supply amount is increased, a misfire or fuel supply is stopped. The engine control method according to any one of claims 1 to 3, wherein the method is performed. 5. A crank that supplies more fuel per combustion cycle to the engine as the engine load increases according to the engine load, and reaches one or more predetermined combustion ratios when a normal combustion state is obtained. The angle value is stored in the memory as map data of the reference crank angle value corresponding to at least the load of the engine speed or the load, while the actual crank angle until the one or more predetermined combustion ratio values is reached is detected. However, based on the comparison between the detected value of the crank angle and the reference crank angle value, when this crank angle is ahead of the reference crank angle, the fuel per combustion cycle is supplied to the engine according to the engine load. A method for controlling an engine, characterized in that the amount is increased more than the amount. 6. A crank that supplies more fuel per combustion cycle to the engine as the engine load increases in accordance with the engine load, and reaches one or more predetermined combustion ratios when a normal combustion state is obtained. The angle value is stored in the memory as map data of the reference crank angle value corresponding to at least the load of the load or the engine speed, while detecting the actual crank angle until the one or more predetermined combustion ratio values are reached. However, based on the comparison between the detected value of this crank angle and the reference crank angle value, when this crank angle leads the reference crank angle by a predetermined angle or more, the fuel per combustion cycle to the engine is changed according to the engine load. A method of controlling an engine, characterized in that the amount of fuel supplied is increased. 7. The engine control method according to claim 5, wherein the larger the advance angle, the more the amount is increased. 8. If the preceding angle amount does not decrease or the preceding angle amount does not decrease more than a predetermined amount even after the fuel supply amount is increased, the misfire or the fuel supply is stopped. The engine control method according to claim 5 or 6, characterized in that. 9. The actual combustion ratio up to one or more predetermined crank angles is a crank angle from the end of the exhaust stroke to the beginning of the compression stroke, and the crank angle from the start of the compression stroke to the start of ignition. The combustion pressure at at least four crank angles consisting of two crank angles within the period from the start of ignition to the start of the exhaust stroke is detected and calculated based on these combustion pressure data. 9. The engine control method according to claim 8.