JP3282890B2 - Engine ignition timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for a supercharged engine provided with an intercooler.

[0002]

2. Description of the Related Art In recent years, many automobiles have been provided with an ignition timing control device for sparking a spark plug at a timing adjusted according to the operating state of an engine or the like. An example of this is an ignition timing control device disclosed in Japanese Patent Application Laid-Open No. 4-203473. This ignition timing control device controls the ignition timing in accordance with the operating state and the temperature of the intake air. The ignition timing is detected by a detection signal from an intake air temperature sensor, an engine speed sensor, or an intake air mass flow sensor. Is set based on the comparison with the map and the calculation based on. The relationship between the ignition timing and the intake air temperature is such that the ignition timing is retarded as the intake air temperature increases.

[0003]

Incidentally, in an engine with a supercharger provided with an intercooler, an intercooler bypass mechanism capable of bypassing the intercooler and taking in air in accordance with the operating state of the engine is provided. There is something. This is because the intercooler bypass mechanism bypasses intake air at a low load or the like, thereby preventing overcooling by the intercooler and preventing deterioration of combustibility. If the ignition timing control device is applied to a vehicle equipped with this bypass mechanism, if the intake air temperature is high, the retard amount will be set to a large value even when the intercooler is bypassed.
However, since the bypass is performed at a low load or the like where the combustibility is likely to deteriorate, if the ignition timing control device performs the retard control, the combustion stability at a further low load may be impaired. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an ignition timing control device for an engine capable of ensuring combustion stability in an intercooler bypass region and improving fuel efficiency. And

[0005]

The invention according to claim 1 is
A supercharger that pressurizes intake air to supply the engine, an intercooler that cools the intake air pressurized by the supercharger, and a bypass mechanism that supplies the intake air to the engine by bypassing the intercooler in a specific operation region of the engine. In the engine provided with the engine, an intake air temperature detecting means for detecting a temperature of the intake air supplied to the engine, an operating state detecting means for detecting an operating state of the engine, Basic ignition timing setting means for setting the timing, correction means for obtaining a correction amount corresponding to the intake air temperature so as to retard the ignition timing as the intake air temperature detected by the intake air temperature detecting means becomes higher, The ignition execution means for performing ignition control based on the final ignition timing obtained from the correction amount and the operation state detection means confirms the operation. Operating conditions of the engine, when an intercooler bypass region bypassing the intake is performed by the bypass mechanism and a configuration in which the correction limiting means for limiting the correction by said correcting means.

According to a second aspect of the present invention, an intercooler bypass region for bypassing intake air is set on the low load side of the engine.

According to a third aspect of the invention, the closing timing of the intake valve is delayed by a predetermined crank angle from the bottom dead center of the piston.

According to a fourth aspect of the present invention, when the operating state of the engine is in an intercooler bypass region, the correction limiting means reduces the correction amount according to the intake air temperature.

According to a fifth aspect of the present invention, the correction means performs the correction when the intake air temperature is equal to or higher than the set start temperature, and the correction restriction means is provided when the operating state of the engine is in the intercooler bypass region. The set start temperature is changed to the high temperature side.

According to a sixth aspect of the present invention, the correction limiter is configured to set the correction amount according to the intake air temperature to zero when the operating state of the engine is in the intercooler bypass region.

[0011]

According to the present invention, when the operating state of the engine is in the intercooler bypass region,
By restricting the retard correction according to the intake air temperature, deterioration of the flammability in this region can be avoided.

According to the second aspect of the present invention, when the operating state of the engine is in the intercooler bypass region, the correction limiting means limits the correction amount for retarding, so that the final ignition is performed in a low load state. Timing retard is suppressed.

According to the third aspect of the invention, when the intake valve is closed with a predetermined angle delay from the bottom dead center of the piston, the effective compression ratio is reduced, and the engine is operated while suppressing knocking. When the operating state of the engine is in the intercooler bypass region, the basic ignition timing setting means sets the basic ignition timing, and the correction limiting means limits the correction amount according to the intake air temperature to correct the basic ignition timing.

According to the fourth aspect of the present invention, when the operating state of the engine is in the intercooler bypass region, the retarding of the final ignition timing is suppressed by the correction limiting means decreasing the correction amount according to the intake air temperature. Is done.

According to the fifth aspect of the present invention, when the operating state of the engine is in the intercooler bypass region, the correction restricting means starts correcting the retard angle after the intake air temperature becomes higher, so that the low intake air amount is obtained. The retard correction at the temperature will be prevented.

According to the sixth aspect of the present invention, when the operating state of the engine is in the intercooler bypass region, the correction limiter sets the correction amount according to the intake air temperature to zero, thereby limiting the delay angle correction. You.

[0017]

FIG. 1 shows a schematic configuration of a supercharged engine to which an ignition timing control device according to the present invention is applied.
The engine 1 with a supercharger will be described with reference to FIG. 1. The engine 1 includes an intake passage 2 that supplies air to the engine, and an engine body 3 to which intake air is supplied by the intake passage 2.

The intake passage 2 has a throttle valve 2
1, a supercharger 22, an intercooler 23, a surge tank 24, an air bypass valve 25, an intercooler bypass valve 26, an intake air temperature detecting means 27, and an aero sensor 28 are provided. The throttle valve 21 adjusts the amount of air supplied to the engine body 3, and the supercharger 22 pressurizes the supplied air. On the other hand, the intercooler 23 is located downstream of the supercharger 22, cools the pressurized intake air and sends it to the surge tank 24.
From 4, the intake air is supplied to each cylinder of the engine body 3. The air bypass valve 25 is
It is provided in a passage 29a that bypasses the supercharger 22, and is opened and closed according to the operation state. The intercooler bypass valve 26 is provided in a passage 29b from the downstream of the supercharger 22 to bypass the intercooler 23 and to the surge tank 24, and is opened and closed according to the operation state. The aero sensor 28 is provided on the upstream side of the throttle valve 21 so that a part of the intake air pressurized by the supercharger 22 can be bypassed without passing through the intercooler 23 when the intake air is opened. The intake air temperature detecting means 27 detects
, And detects the temperature of intake air supplied to the engine.

The engine body 3 includes a spark plug 32 for igniting the air-fuel mixture in a cylinder 31, an intake valve 33 for supplying and stopping the air-fuel mixture, and an engine speed sensor 34 for detecting the engine speed. And The intake valve 33 is opened and closed by a valve mechanism including a camshaft and the like. The intake valve 33 is closed by rotating the crankshaft by 50 degrees or more from the time when the piston 36 passes the bottom dead center. It is a so-called late closing intake valve. In this manner, the compression top dead center temperature is reduced by reducing the effective compression ratio by the late closing while securing the intake charge amount by the supercharging, thereby suppressing the occurrence of knocking.

The detection signals of the engine speed sensor 34 and the aero sensor 28 constituting the intake temperature detecting means 27 and the operating state detecting means are input to a control unit described later. The air bypass valve 25 and the intercooler bypass valve 26 constituting the bypass mechanism are connected to the output side of a control unit, and these valves 25 and 26 are opened and closed by an output signal of the control unit. .

Further, the supercharged engine 1 is provided with a control section 4 for controlling the operating state of the engine. As shown in FIG. 2, the control unit 4 includes the air bypass valve 25 and the intercooler bypass valve 2.
6; a basic ignition timing setting means 42 for setting a basic ignition timing of the spark plug 32;
Correction means 43 for retarding the basic ignition timing, correction restriction means 45 for restricting this correction in the case of an intercooler bypass region, and ignition execution means for igniting the spark plug 32 according to the corrected ignition timing. 44, a control map 46 for defining a control area of the bypass mechanism and the like,
A retard amount correction map 47 in which a correction amount for retarding the basic ignition timing is defined is provided.

Further, in the control unit 4, the detection signal of the aero sensor 28 is subjected to arithmetic processing, thereby obtaining the charging efficiency CE of the intake air representing the load of the engine, and the charging efficiency CE and the engine speed sensor 34. The engine operation state can be confirmed by the engine speed (rpm) according to the above.

As shown in FIG. 3, the control map 46 includes an intercooler bypass region for driving the bypass mechanism when the load on the engine is low, and a normal delay for delaying the basic ignition timing in accordance with the intake air temperature. An angle control area is set. Specifically, the intercooler bypass region is set in a low load range that is equal to or less than a predetermined load (for example, the intake air charging efficiency CE is 0.6). The normal retard control region is a region other than the intercooler bypass region, and is set to a range of a predetermined load or more and a predetermined rotation speed (for example, the rotation speed is 500 rpm) or more. Therefore, by using the control map 46, it is possible to confirm which of the above-mentioned regions the operating state of the engine belongs to at the time based on the rotation speed by the engine rotation speed sensor 34 and the load value by the aero sensor 28. Has become.

The retard amount correction map 47 defines a retard amount (the above-mentioned correction amount) for retarding the basic ignition timing in accordance with the detected intake air temperature, as shown in FIG. The retard amount correction map 47 includes a retard amount indicated by a solid line in FIG. 4 for retard correction in a normal retard control region, and a retard amount indicated by a dashed line in FIG. 4 for retard correction in an intercooler bypass region. The amount is set respectively. When the operating state of the engine is in the normal retard control region, the correction means 43 obtains the correction amount based on the curve shown by the solid line. By calculating the correction amount based on the above, the correction amount is reduced in the case of the intercooler bypass region, and the set start temperature at which the correction is started is changed to the high temperature side.

When the supercharge control means 41 determines that the operation state of the engine is in the intercooler bypass region based on the detection signals from the engine speed sensor 34 and the aero sensor 28, the supercharge control means 41 controls the air bypass valve 25 and the intercooler bypass. By opening the valve 26, a part of the intake air pressurized by the supercharger 22 is re-used.
And the air is supplied to the surge tank 24 at a high temperature while bypassing the intercooler 23. Thus, by preventing the supercooling by the intercooler 23, the vaporization and atomization of the fuel at the time of a low load is improved. When the operating state of the engine becomes a high load state equal to or more than a predetermined value, by closing the two valves 25 and 26,
The intake air is pressurized by a supercharger 22, and the pressurized intake air is cooled by an intercooler 23, and then supplied to the engine body 3 via a surge tank 24.

On the other hand, the basic ignition timing setting means 42
The basic ignition timing is set on the basis of a map (not shown) and the detection signal of the motion state detection means, and the correction means 43 and the correction restriction means 45 correct the retard amount in accordance with the operating state of the engine and the intake air temperature. A correction amount for retardation is extracted from the map 47, and the basic ignition timing is retarded and corrected by the extracted correction amount to set a final ignition timing. Based on the final ignition timing, the ignition execution means 44 performs ignition. The plug 32 is made to spark.

Next, the basic ignition timing setting means 42,
Correction means 43, correction restriction means 45, and ignition execution means 4
The ignition control operation of the ignition plug 32 constituting the fourth embodiment 4 will be described based on the flowchart shown in FIG. First, in step S1, the intake air temperature detecting means 27 and the engine speed sensor 3
4. Various detection signals from the aero sensor 28 and the like are read, and in step 2, the basic ignition timing is obtained based on the various input signals already read and a map (not shown) set in advance. On the other hand, in step S3, based on the load value (intake charging efficiency CE) determined from the read input signal and the engine speed, the control map shown in FIG. It is determined whether the engine is in a high load state. If the determination is NO, the process proceeds to step S4.

In step S4, the retard amount corresponding to the intake air temperature is obtained from the retard curve shown by the solid line in the retard amount correction map shown in FIG. 4, and thereafter, in step S5, another correction amount, for example, a knocking sensor (not shown)
Set the amount of retard for knocking suppression based on
In step 6, the final ignition timing is set based on the basic ignition timing, the retard amount according to the intake air temperature, and the other retard amounts. In step S7, the spark plug 32 is sparked based on the final ignition timing. .

Since the engine is in the intercooler bypass region, if the result of the determination in step S3 is YES, the process proceeds to step S8, and the intake air temperature is determined by the retard amount curve shown by the one-dot chain line in the retard amount correction map of FIG. The retard amount corresponding to is calculated, and step S6
The basic ignition timing is retarded and corrected based on the retard amount and the other retard amounts.

By controlling in this manner, when the operating state of the engine is in the intercooler bypass region, the retard amount is smaller than the retard amount for the normal retard control region shown by the solid line in FIG. 4 dot-dash line)
As a result, the ignition timing is retarded, and the stability of combustion under a low load condition can be improved.

In the above engine, the intake valve 33
Is driven by the intake late closing and the effective compression ratio is reduced, so that the occurrence of knocking is suppressed, so that the setting start temperature of the retard amount for correcting the retard in the intercooler bypass region is set to the normal retard control region. Can be set to a temperature higher than the setting start temperature, as a result, when the intake air temperature is low and the load is low, the retard correction is prevented,
Combustion stability under low load conditions is ensured.

Further, the above step S8 is performed without obtaining the retard amount from the retard curve shown by the one-dot chain line in FIG.
The retard amount may be set to zero. When step S8 is configured in this manner, if YES is determined in step S3, the retard amount for retard correction is set to zero in step S8, and the retard amount by other correction is obtained in step S5. In step S6, the basic ignition timing is retarded by the retard amount obtained by other corrections, and the final ignition timing is set. When step S8 is configured as described above,
The retard amount correction map shown in FIG. 4 can be simplified.

FIG. 6 shows the relationship between the load and the intake air temperature in the supercharged engine equipped with the ignition timing control device according to the present invention. That is, when the load of the engine is small and the engine is in the intercooler bypass region at the normal outside air temperature, the intake passage 2 bypasses the intercooler 23 to supply the intake air to the engine, and the intake air temperature is indicated by a solid line in FIG. However, when the load increases, the detour is stopped and the cooling of the intake air by the intercooler 23 is started, so that the intake air temperature decreases at this time. However, when the load further increases, the intake air temperature increases with an increase in the intake air amount.

The intake air temperature is also affected by the outside air temperature,
When the outside air temperature is higher than normal, it becomes as shown by the broken line in FIG. 6, and the temperature characteristic in the case of the normal outside air temperature is shifted to a higher intake air temperature. The temperature characteristic enters the knocking occurrence region. The knocking occurrence region indicates a region where knocking may occur, and is limited to a high load and a high intake air temperature as shown in FIG.

Therefore, by setting the intercooler bypass region in the control map to a low load side, the knocking region does not reach even if the intake air temperature rises as shown in FIG. In this case, the ignition retard amount can be greatly limited, and reliable combustion stability can be obtained in a low load state.

The setting of the retard amount in step S8 may be performed using a map which is set in advance based on the intake air temperature and the load as shown in FIG.
In this map, a large number of curves A1 to An for each retard amount determined by the relationship between the intake air temperature and the engine load are set. In these curves, the greater the intake air temperature and the load are associated, the larger the retard amount is set.

When this map is provided in the control unit 4, if the result of the determination in step S3 is YES because the engine is in a low load state, in step S8, the curves A1 to An of the map shown in FIG. A curve corresponding to the intake air temperature and load at that time is selected, and the retard amount associated with the curve is set as a correction amount for retard correction. Thereafter, in step S6, the final ignition timing is set by retarding the basic ignition timing based on the retard amount or the like. By performing such control in step S8, it is possible to perform retard correction with a small retard amount for each state of the intake air temperature and the load.

[0038]

As described above, the present invention provides a supercharger,
In an engine equipped with an intercooler bypass mechanism, the correction of the ignition timing such that the retard amount is increased as the intake air temperature becomes higher is limited in the intercooler bypass region. In the above, the combustion stability can be ensured by preventing the deterioration of the flammability due to the ignition retard.

In particular, when the intercooler bypass region is set to a low load side, combustion stability at a low load can be ensured at a high load side while knocking is sufficiently suppressed by retarding the ignition timing.

Further, a basic ignition timing setting means for setting a basic ignition timing and a correction means for retarding the basic ignition timing based on the intake air temperature are provided to a control unit of the supercharged engine with the intake late closing. In the case of the intercooler bypass region, when a configuration is provided in which a correction limiting unit that limits this retardation correction and an ignition execution unit that executes ignition based on the corrected ignition timing are provided, the effective compression ratio decreases. As a result, knocking is less likely to occur, so that the amount of correction for retarding can be further limited, and the stability of combustion at low load can be further improved.

When the operating state of the engine is in the intercooler bypass region, the correction limiter sets the correction amount reduced as compared with the correction amount for the normal retard control region, or When the setting start temperature of the correction amount for the intercooler bypass region is set to be higher than the setting start temperature for the normal retard control region, the correction amount for the same intake air temperature is suppressed, and at the time of low load. Combustion stability can be improved.

Further, when the operation state is in the intercooler bypass region, if the ignition timing correction means is configured to set the correction amount to zero, the ignition timing control device in the ignition timing control device can maintain the stability of combustion at low load. The control can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram of a supercharged engine to which the present invention is applied.

FIG. 2 is a block diagram of a control system that controls the supercharged engine.

FIG. 3 is a control map that defines a normal retard control region and an intercooler bypass region when the engine is operating.

FIG. 4 is a retard amount correction map that defines a retard amount for retard correction performed in each of the normal retard control region and the intercooler bypass region.

FIG. 5 is a flowchart illustrating an ignition timing control operation according to the present invention.

FIG. 6 is a graph showing a change in intake air temperature with respect to a change in load and a knocking occurrence region in the engine with a supercharger.

FIG. 7 is another retardation amount correction map that defines a retard amount for retardation correction based on a load and intake air temperature.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine with a supercharger 2 Intake passage 3 Engine main body 4 Control part 21 Throttle valve 22 Supercharger 23 Intercooler 25 Air bypass valve 26 Intercooler bypass valve 27 Intake temperature detection means 28 Aero sensor 32 Spark plug 33 Intake valve 34 Engine speed Sensor 42 Basic ignition timing setting means 43 Correction means 44 Ignition execution means 45 Correction restriction means 46 Control map 47 Delay angle correction map

Continuation of front page (56) References JP-A-62-153517 (JP, A) JP-A-63-65172 (JP, A) JP-A-63-88276 (JP, A) JP-A-60-252169 (JP, A) JP-A-4-353269 (JP, A) JP-A-5-149226 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02P 5/15 F02D 45/00 345

Claims (6)

(57) [Claims] 1. A supercharger for pressurizing intake air to supply the engine to an engine, an intercooler for cooling the intake air pressurized by the supercharger, and an intake air for the engine bypassing the intercooler in a specific operation region of the engine. In an engine including a supply bypass mechanism, based on intake air temperature detection means for detecting the temperature of intake air supplied to the engine, operation state detection means for detecting an operation state of the engine, and the motion state detection means and the like. Basic ignition timing setting means for setting a basic ignition timing of a spark plug; and correction means for obtaining a correction amount according to the intake air temperature so that the ignition timing is retarded as the intake air temperature detected by the intake air temperature detection means increases. Ignition execution means for performing ignition control based on the final ignition timing obtained from the basic ignition timing and the correction amount; and Therefore, when the operating state of the engine confirmed is the intercooler bypass region where the bypass of the intake air is being performed by the bypass mechanism, correction limiting means for limiting correction by the correction means is provided. Ignition timing control device. 2. The engine ignition timing control device according to claim 1, wherein an intercooler bypass region for bypassing intake air is set on a low load side of the engine. 3. The engine ignition timing control device according to claim 1, wherein the closing timing of the intake valve is set with a predetermined crank angle delay from the bottom dead center of the piston. 4. The engine according to claim 1, wherein the correction restricting means decreases a correction amount according to the intake air temperature when an operation state of the engine is in an intercooler bypass region. Ignition timing control device. 5. The correction means performs correction when the intake air temperature is equal to or higher than a set start temperature. When the engine operating state is in the intercooler bypass region, the correction limit means sets the set start temperature to a high temperature side. The engine ignition timing control device according to claim 1, 2 or 3, wherein the ignition timing control device is changed to: 6. The engine according to claim 1, wherein the correction restricting means sets a correction amount according to the intake air temperature to zero when an operation state of the engine is in an intercooler bypass region. Ignition timing control device.