JP4220736B2 - Start control device for spark ignition type internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a start control device applied to a spark ignition type internal combustion engine, and more particularly to a start control device for a spark ignition type internal combustion engine suitable for start control at a low engine temperature.
[0002]
[Prior art]
When starting the spark ignition internal combustion engine, hard ignition, that is, ignition is performed at a predetermined time. The ignition timing at the start is generally set to a compression top dead center that is an ignition timing at which good combustion is performed from the viewpoint of ensuring startability.
[0003]
On the other hand, in a spark ignition type internal combustion engine, since the fuel is vaporized well at the time of start-up (at the time of normal temperature start-up) with the engine temperature sufficiently high, a small amount of fuel is injected. On the other hand, at the time of start-up when the engine temperature is low (during cold start), the fuel vaporization rate decreases, so that more fuel is injected than at the time of start-up when the engine temperature is high. The
[0004]
[Problems to be solved by the invention]
However, in the spark ignition internal combustion engine, there is a problem that a large amount of smoke is generated when hard ignition is performed at the time of start-up with the engine temperature lowered. A possible cause of this smoke generation is that an excessive amount of fuel is injected and the combustion field becomes hot.
[0005]
That is, when ignition is performed at the compression top dead center where the in-cylinder pressure is high, the air-fuel mixture burns with rapid heat generation, so the combustion field tends to become high regardless of the engine temperature. On the other hand, at the time of starting in a state where the engine temperature is high, as described above, a small amount of fuel is injected, and there is little surplus fuel in the cylinder. For this reason, as described above, even if the combustion field becomes high temperature, smoke is not generated so much. On the other hand, at the time of starting with the engine temperature lowered, a large amount of fuel is injected as described above. Among these, a large amount of fuel that does not contribute to combustion adheres to the piston top surface and the cylinder wall surface and becomes so-called wall surface wet and exists in the combustion field. For this reason, when the combustion field becomes high temperature by ignition at the compression top dead center, a large amount of smoke is generated. The amount of smoke generated increases as the injection amount increases as the engine temperature decreases and the surplus (excess) fuel in the cylinder increases.
[0006]
In particular, in a spark ignition internal combustion engine that directly injects fuel into the cylinder, the amount of fuel that adheres to the cylinder inner wall surface during start-up is greater than that in which fuel is injected into the intake passage (intake port). The amount of smoke generated tends to increase further.
[0007]
For example, Japanese Patent Application Laid-Open No. 11-62680 proposes a technique for reducing the amount of wet wall when starting with the engine temperature lowered. This technique performs divided injection when engine start completion is detected. That is, by reducing the amount of fuel injected at one time, the inertial force of the fuel is reduced, the penetration force is weakened, and the fuel adheres to the cylinder wall surface. However, even if the amount of wet wall surface is reduced in this way, there is no change in that a large amount of fuel that does not contribute to combustion exists in the cylinder. Therefore, there is still a problem that a large amount of smoke is generated in this case.
[0008]
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a start control device capable of suppressing the occurrence of smoke when a spark ignition internal combustion engine is started at a low engine temperature. It is to provide.
[0009]
[Means for Solving the Problems]
In the following, means for achieving the above object and its effects are described.
In the first aspect of the invention, it is applied to a spark ignition type internal combustion engine, and cranking is performed when the engine temperature is low based on the engine temperature or engine information corresponding thereto. During the period including the first explosion There is provided ignition timing control means for retarding the ignition timing after the compression top dead center.
[0010]
According to the above configuration, when the engine temperature is low, the crank timing is controlled by the ignition timing control means. During the period including the first explosion The ignition timing is retarded after compression top dead center. When ignition is performed at the corrected ignition timing, the combustion becomes slow and the increase in the combustion temperature is suppressed. As a result, the phenomenon that the combustion field becomes high temperature is suppressed, and smoke is hardly generated.
[0011]
According to a second aspect of the present invention, in the first aspect of the present invention, there is further provided an air flow control means for imparting an air flow to the mixture in the cylinder when the ignition timing is retarded.
[0012]
Here, the greater the retard amount of the ignition timing, the slower the combustion and the greater the effect of reducing smoke. However, if the ignition timing is retarded excessively, the combustion becomes too slow and the output torque of the internal combustion engine decreases. Due to this decrease, it may be difficult to secure an output torque comparable to that in the case where the ignition delay is not performed.
[0013]
In this regard, according to the second aspect of the present invention, when the ignition timing is retarded, an air flow is imparted to the air-fuel mixture in the cylinder by the air flow control means. By this application, the combustion speed is increased, and an output torque equivalent to the case where the retardation correction is not performed is generated. Thus, according to the second aspect of the present invention, the output torque can be ensured while suppressing the combustion field from becoming high temperature.
[0014]
According to a third aspect of the invention, in the second aspect of the invention, the ignition timing control means increases the retard correction amount of the ignition timing as the engine temperature is lower. It is assumed that the airflow of the air-fuel mixture increases as the retardation correction amount increases.
[0015]
According to the above configuration, the ignition timing retardation correction amount by the ignition timing control means increases as the engine temperature decreases. That is, the injection amount is increased as the engine temperature is lowered, but the ignition timing is corrected to the retard side more in accordance with the increase. Therefore, although the phenomenon that the combustion becomes slow and the combustion field becomes high temperature is suppressed and smoke is hardly generated, the combustion speed becomes slow as the engine temperature decreases, and it may be difficult to secure the output torque. However, the degree of airflow application by the airflow control means increases as the retardation correction amount increases. By strengthening this air flow, the decrease in the combustion speed is compensated, and it becomes possible to ensure the same output torque as when the retard angle correction is not performed regardless of the engine temperature.
[0016]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the ignition timing control means further includes a decrease in cranking rotational speed of the spark ignition type internal combustion engine. Assume that the retard correction amount of the ignition timing is increased.
[0017]
Here, the cranking rotation speed may decrease due to the type and amount of the lubricating oil or contamination of foreign matter. And since the movement speed of a piston becomes slow by this fall, combustion will be performed on the top dead center side, a lot of heat will be generated, and combustion temperature will become high. That is, when the cranking rotational speed is decreased, the combustion temperature is greatly affected and increased even if the rotational speed is decreased, and the amount of smoke generated may increase.
[0018]
On the other hand, in the invention according to claim 4, when the cranking rotation speed is lowered, the ignition timing control means increases the retard correction amount of the ignition timing more than the retard correction amount based only on the engine temperature. For this reason, the phenomenon that the combustion temperature increases with a decrease in the cranking rotational speed is suppressed, and smoke does not easily occur.
[0019]
The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the spark ignition internal combustion engine is a multi-point ignition system that performs spark discharge at different locations of the same cylinder. In the internal combustion engine, when the engine temperature is low, the ignition timing control means sets all ignition timings at the time of cranking after the compression top dead center.
[0020]
According to the above configuration, when the engine temperature is low, the ignition timing of all points at the time of cranking is set after the compression top dead center by the ignition timing control means. Therefore, even in the case of a multi-point ignition type internal combustion engine, combustion is slowed by retarding the ignition timing after the compression top dead center, and an increase in combustion temperature is suppressed. As a result, the same effects as those of the invention according to claim 1 can be obtained without impairing the original effects of the multiple ignition system, such as improving combustion efficiency by improving combustion efficiency and obtaining high output without advancing the ignition timing. Further, it is possible to suppress the generation of smoke due to the high temperature of the combustion field.
[0021]
Note that when spark discharge (simultaneous ignition at a plurality of points) is simultaneously performed at a plurality of different locations in the same cylinder, the combustion ratio in a certain period increases as compared with the case where spark discharge (one-point ignition) is performed at one location. This increase may cause combustion with high heat generation in a short period of time, resulting in a high temperature in the combustion field. Therefore, it is desirable to set the ignition timing retardation correction amount larger in the case of multiple simultaneous ignitions than in the case of single point ignition.
[0022]
The invention according to claim 6 is the invention according to any one of claims 1 to 4, wherein the spark ignition type internal combustion engine is a multi-point ignition type in which spark discharge is performed at different locations in the same cylinder. It is an internal combustion engine, and the ignition timing control means performs one-point ignition at the time of cranking when the engine temperature is low, and sets the ignition timing at this time after compression top dead center.
[0023]
Here, when spark discharge (multi-point simultaneous ignition) is performed at different locations in the same cylinder, the combustion rate in a certain period increases compared to when spark discharge (single-point ignition) is performed at one location, and the short-term Combustion with high heat generation occurs between them, and the combustion field tends to become hot. Therefore, at the time of normal temperature starting when a small amount of fuel is injected, combustion efficiency can be increased and fuel consumption can be improved. However, if ignition is performed simultaneously at a plurality of points at the time of start-up with the engine temperature being low, a large amount of fuel is injected, so that a large amount of smoke may be generated.
[0024]
In this respect, in the invention according to claim 6, when the engine temperature is low, the ignition timing control means sets one ignition at the time of cranking, and the ignition timing at this time is set after the compression top dead center. Therefore, as in the first aspect of the invention described above, the combustion becomes slow and the increase in the combustion temperature is suppressed, the phenomenon that the combustion field becomes high temperature is suppressed, and smoke is hardly generated. Further, at the time of normal temperature start when a small amount of fuel is injected with a high engine temperature, ignition is performed at a plurality of locations during cranking. For this reason, combustion efficiency can be raised and fuel consumption can be improved.
[0025]
According to a seventh aspect of the invention, in the invention according to any one of the first to sixth aspects, the spark ignition type internal combustion engine is an in-cylinder injection type internal combustion engine that directly injects fuel into a cylinder. And
[0026]
In a spark ignition type internal combustion engine that directly injects fuel into the cylinder, more fuel adheres to the cylinder inner wall surface at the time of start-up than in the case of injecting fuel into the intake passage (intake port). It tends to increase. Therefore, when the engine temperature is low, the ignition timing at the time of cranking of the cylinder injection internal combustion engine is retarded after the compression top dead center, thereby suppressing the occurrence of smoke. Can be obtained.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0028]
An in-cylinder injection gasoline engine (hereinafter simply referred to as an engine) 11 that is a spark ignition type internal combustion engine that directly injects fuel into a cylinder is mounted on the vehicle as a prime mover. This type of engine 11 is characterized in that an output improvement accompanying an increase in charging efficiency by in-cylinder injection, an improvement in fuel consumption due to the stratification of the air-fuel mixture, and the like can be obtained. The engine 11 has a plurality of cylinders 12, and a piston 13 is accommodated in each cylinder 12 so as to be able to reciprocate. Each piston 13 is connected to a crankshaft 15 that is an output shaft of the engine 11 via a connecting rod 14. The reciprocating motion of each piston 13 is converted into rotational motion by the connecting rod 14 and then transmitted to the crankshaft 15.
[0029]
An intake passage 17 for taking air outside the engine 11 into the combustion chamber 16 is connected to the combustion chamber 16 for each cylinder 12. The combustion chamber 16 is connected to an exhaust passage 18 for discharging exhaust gas generated in the combustion chamber 16 to the outside of the engine 11. The engine 11 is provided with an intake valve 19 and an exhaust valve 20 that can reciprocate in the axial direction. The intake / exhaust valves 19 and 20 are reciprocated to open and close the intake passage 17 and the combustion chamber 16, and the exhaust passage 18 and the combustion chamber 16, respectively.
[0030]
A throttle valve 21 is rotatably provided in the intake passage 17. An actuator 22 such as a step motor is drivingly connected to the throttle valve 21. The actuator 22 is controlled by an ECU 35 (which will be described later) and rotates the throttle valve 21. The amount of air flowing through the intake passage 17 changes according to the rotation angle of the throttle valve 21.
[0031]
An electromagnetic fuel injection valve 23 is attached to the engine 11 corresponding to each cylinder 12. The fuel injection valves 23 are connected to a delivery pipe 24 that is a common high-pressure fuel pipe, and the high-pressure fuel in the delivery pipe 24 is distributed and supplied to the fuel injection valves 23. Each fuel injection valve 23 is directly controlled to open and close, thereby directly injecting high-pressure fuel into the corresponding cylinder 12. The injected fuel mixes with the intake air taken into the cylinder 12 through the intake passage 17 and becomes an air-fuel mixture.
[0032]
A spark plug 25 is attached to the engine 11 corresponding to each cylinder 12. The spark plug 25 is driven based on an ignition signal from the igniter 26. A high voltage output from the ignition coil 27 is applied to the spark plug 25. The air-fuel mixture is ignited by the spark discharge of the spark plug 25 and explodes and burns. The piston 13 is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, the crankshaft 15 is rotated, and the driving force (output torque) of the engine 11 is obtained.
[0033]
Various sensors are provided in the vehicle to detect the operating state of the engine 11. For example, a crank angle sensor 31 that generates a pulse-like signal every time the crankshaft 15 rotates by a certain angle is provided in the vicinity of the crankshaft 15. A signal from the crank angle sensor 31 is a crank angle (° CA, where CA is an abbreviation for crank angle), which is a rotation angle of the crankshaft 15, and an engine rotation speed, which is a rotation speed of the crankshaft 15 per unit time. Used for calculation of NE and the like. Further, the engine 11 is provided with a water temperature sensor 32 for detecting the temperature of the cooling water (cooling water temperature THW).
[0034]
The engine 11 is provided with a starter (not shown) for applying a rotational force to the crankshaft 15 by cranking at the time of starting. The starter operates according to the operation of the starter switch 33 by the driver. That is, the starter is operated while the starter switch 33 is operated to the start position. When the starter is operating, a starter signal is output. Many other sensors are attached to the engine 11 and the like, but the description thereof is omitted here.
[0035]
An electronic control unit (ECU) 35 is provided to control each part of the engine 11 based on detection values of various sensors including the crank angle sensor 31, the water temperature sensor 32, and the starter switch 33. The ECU 35 is configured around a microcomputer, and a central processing unit (CPU) performs arithmetic processing according to a control program and initial data stored in a read-only memory (ROM), and performs various controls based on the calculation results. Execute. The calculation result by the CPU is temporarily stored in a random access memory (RAM). The ECU 35 determines the operating state of the engine 11 based on detection signals from the various sensors 31 to 33 and the like, and based on the operating state and a predetermined arithmetic expression or a predetermined control map, the fuel injection amount, the fuel injection timing, The opening degree of the throttle valve 21 and the ignition timing are calculated. Then, the ECU 35 outputs a control signal to the actuator 22, the fuel injection valve 23, the igniter 26 and the like based on the calculation result.
[0036]
Here, in the engine 11 configured as described above, at the time of cold (low temperature) start in which a large amount of fuel is injected, a large amount of fuel that does not contribute to combustion adheres to the in-cylinder wall surface. Become in the combustion field. This wet wall surface contributes to the generation of a large amount of smoke (black smoke). In particular, in the in-cylinder injection type engine 11 as in this embodiment, the amount of fuel adhering to the in-cylinder wall surface at the time of starting is larger than in the case of injecting into the intake passage (intake port), and therefore smoke tends to further increase. It is in.
[0037]
It is conceivable that smoke is generated in the engine 11 because fuel is excessively injected and the combustion field in the cylinder becomes high temperature. Therefore, as countermeasures for suppressing the generation of smoke, it is conceivable to (a) reduce the fuel injection amount and (b) suppress the combustion field from becoming high temperature. Next, we will examine the appropriateness of these measures.
[0038]
(A) Reduction of fuel injection amount
When the engine 11 is started in a state where the engine temperature is lowered, the rate of vaporization of the injected fuel is reduced. Therefore, a large amount of fuel injection is indispensable for forming a good mixture. Decreasing the injection amount leads to deterioration of startability. Therefore, although reducing the injection amount is effective from the viewpoint of suppressing the occurrence of smoke, it causes a problem that startability deteriorates.
[0039]
(B) Suppression of high temperature combustion field generation
In order to reduce the combustion speed in the engine 11, it is important to suppress the rapid generation of heat. As the means, the introduction of EGR (exhaust gas recirculation), the reduction of the compression ratio, the ignition timing It is considered effective to retard and slow down the combustion.
[0040]
Here, the amount of smoke generated at the start is the largest during the first combustion, that is, at the first explosion. However, since combustion is not performed in the combustion cycle immediately before the first explosion, EGR that recirculates a part of the exhaust gas to the intake passage suppresses the occurrence of smoke for the first explosion that most wants to suppress the occurrence of smoke. Difficult to do. In addition, after the first explosion, during the period from when the engine rotational speed NE rises to when the first idle is performed, the combustion for each combustion cycle and the negative pressure generated in the engine 11 change greatly, so the EGR amount is controlled accurately. Difficult to do. As a result, the combustion state becomes unstable and there is a risk of causing rotational fluctuation.
[0041]
As for the compression ratio, it is difficult to mechanically reduce the compression ratio only at the start. Also, the control for changing the actual compression ratio using the variable valve system is difficult at the start-up when the combustion state changes suddenly for each combustion cycle. Moreover, since the internal EGR is also changed at the same time, the combustion fluctuation is caused as in the case of the EGR control.
[0042]
On the other hand, with the retard control of the ignition timing, there are few problems such as deterioration of combustion fluctuations. That is, with respect to the crank angle, since a stable combustion is performed in a certain period after the compression top dead center (TDC), there is little combustion fluctuation. According to experiments, the end of this period is about 12 ° CA after compression top dead center. Therefore, when the ignition timing is retarded, it is possible to satisfy contradictory requirements such as securing output torque and suppressing smoke generation within this period. In the first embodiment, attention is paid to this point, and the generation of smoke is suppressed by retarding the ignition timing at the time of starting at a low engine temperature.
[0043]
Next, a description will be given of the control at the time of engine start including the ignition timing retard control. The flowchart of FIG. 2 shows a routine for calculating the final ignition timing SAfin in the control performed at engine start. This routine is started when the starter switch 33 is turned on by the driver, and is executed only for a predetermined period after the initial explosion until the engine speed NE reaches a predetermined value.
[0044]
The ECU 35 first reads engine information in step 110. The engine information includes the engine temperature or its equivalent value, the engine speed NE, the starting injection amount q, and the like. As the engine temperature, for example, the cooling water temperature THW detected by the water temperature sensor 32 can be used. Further, examples of the equivalent value of the engine temperature include oil temperature and intake air temperature. As these oil temperature, intake air temperature, etc., for example, values detected by sensors for engine control or the like can be used. In addition, a dedicated sensor may be provided and the detection value of the sensor may be used.
[0045]
The starting injection quantity q is calculated based on the engine temperature, the engine speed NE, and the like in another calculation routine. Here, since the fuel vaporization deteriorates when the engine temperature is low, the calculated starting injection quantity q increases as the engine temperature (cooling water temperature THW) decreases, as shown in FIG. Further, since the turbulence of the air flow in the cylinder 12 is strengthened and the vaporization is promoted as the engine rotational speed NE increases, the calculated starting injection quantity q decreases as the engine rotational speed NE increases.
[0046]
Next, at step 130 in FIG. 2, the basic ignition timing SAbase is calculated based on the engine speed NE and the starting injection quantity q. For this calculation, for example, a map shown in FIG. 4 is used. In this map, the engine rotation speed NE and the injection amount q at the start time and the basic ignition timing are advanced so that the basic ignition timing SAbase is advanced as the engine rotation speed NE is increased and the injection amount q at the start is decreased. The relationship with SAbase is defined.
[0047]
Subsequently, in step 140 of FIG. 2, based on the coolant temperature THW and the engine speed NE read in step 110, an ignition timing correction amount SAtemp for suppressing the combustion field from becoming high temperature is calculated. For this calculation, for example, a map shown in FIG. 5 is used. In this map, in the region where the coolant temperature THW is high, the correction amount SAtemp is set to “0” regardless of the engine speed NE. On the other hand, in the low coolant temperature THW region where the amount of smoke generated increases, the correction amount SAtemp is set to a retarded value as the coolant temperature THW decreases and as the engine speed NE decreases. .
[0048]
Next, in step 180 of FIG. 2, the final ignition timing SAfin is calculated based on the basic ignition timing SAbase and the correction amount SAtemp obtained in steps 130 and 140. Here, the correction amount SAtemp is added to the basic ignition timing SAbase, and the addition result is set as the final ignition timing SAfin. As described above, this final ignition timing SAfin is a value that is retarded from the conventional ignition timing (compression top dead center). Then, after the processing of step 180, a series of processing of this routine is once ended.
[0049]
The igniter 26 is controlled based on the final ignition timing SAfin calculated in this way. By this control, spark discharge is performed by the spark plug 25, and the air-fuel mixture is ignited and burned. The ignition timing control means is configured by the ECU 35 that performs the calculation processing of the final ignition timing SAfin in step 180 and the control processing of the igniter 26 based on the final ignition timing SAfin.
[0050]
The start-up control routine is executed during the predetermined period as described above. When this predetermined period has elapsed, normal ignition timing control without retardation correction is performed.
[0051]
Therefore, according to the first embodiment, the following effects can be obtained.
(1) When the engine temperature is low, the ignition timing at the time of cranking is retarded after the compression top dead center. When ignition is performed at this retarded ignition timing, combustion becomes slower than in the case where retarded angle correction is not performed, and an increase in combustion temperature is suppressed. As a result, it is possible to suppress the generation of smoke due to the high temperature of the combustion field.
[0052]
6 to 8 show the effect obtained by retarding the ignition timing from the compression top dead center. In FIG. 6, as indicated by the broken line, when the final ignition timing SAfin is set to the compression top dead center (TDC) regardless of the coolant temperature THW (corresponding to the prior art), the ignition is performed when the in-cylinder pressure is the highest. Will be done. Therefore, the combustion field becomes a high temperature regardless of the coolant temperature THW. Whether the cooling water temperature THW is high (see the dashed line in FIG. 7) or low (see the broken line in FIG. 7), the heat generation rate, which is the amount of heat generated per unit crank angle, is the compression top dead center (TDC). It rises rapidly to a high value in a short period later. In this way, high combustion heat is generated regardless of the coolant temperature THW, and the combustion field becomes high temperature. Therefore, when the engine is started with the cooling water temperature THW low, the injection amount increases as the cooling water temperature THW decreases, and the excess fuel existing in the cylinder increases. As shown by the broken line in FIG. The concentration of becomes higher.
[0053]
On the other hand, in the first embodiment in which the ignition timing is retarded after the compression top dead center as the cooling water temperature THW decreases, the combustion becomes slow as shown by the solid line in FIG. ) The increase in combustion temperature is suppressed, and the smoke concentration decreases as shown by the solid line in FIG.
[0054]
Note that, as a matter of concern when the ignition timing is retarded, it is conceivable that the output torque decreases due to slow combustion, the startability deteriorates, and the rotational speed rises.
[0055]
However, according to experiments, for example, for the first explosion, there is almost no decrease in output torque even when ignition is performed at a delay of about 12 ° CA from the compression top dead center, which is equivalent to the case of ignition at the compression top dead center. It was found that the startability of can be secured. The reason is considered as follows. By retarding the ignition timing, the interval from when the fuel is injected until it is ignited becomes longer, and the fuel vaporization time becomes longer. As a result, compared to the case where ignition is performed at the compression top dead center, the air-fuel mixture is better formed when the ignition is delayed from the compression top dead center. Therefore, although the combustion becomes slow with the retard of the ignition timing, the total heat generation amount increases, and as a result, the output torque can be secured. As described above, as long as the ignition angle is retarded within a certain range, the smoke can be reduced while ensuring startability.
[0056]
(2) The engine 11 of this embodiment is an in-cylinder injection type engine. However, in this type, the fuel adhering to the in-cylinder inner wall surface at the time of starting is greater than that of an engine that injects into the intake passage (intake port). Since the amount is large, the amount of smoke generated tends to further increase. Therefore, in the in-cylinder injection engine 11, when the engine temperature is low, the ignition timing at the time of cranking is retarded after the compression top dead center to suppress the occurrence of smoke. An effect can be obtained.
[0057]
(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. 1 and 9 to 12. The second embodiment is different from the first embodiment in that the second embodiment further includes an air flow control means for applying an air flow to the air-fuel mixture in the cylinder 12 when the ignition timing is corrected to retard.
[0058]
FIG. 9 shows the positional relationship between the intake / exhaust valves 19 and 20, the intake / exhaust passages 17 and 18, and the spark plug 25 in each cylinder 12. An intake passage 17 connected to each cylinder 12 is branched into two at a location near the cylinder 12. An airflow control valve 41 is rotatably supported by a shaft 42 in one of the branched passages. As shown by a two-dot chain line in FIG. 1, an actuator 43 such as a motor is drivingly connected to the airflow control valve 41. This air flow control valve 41 imparts an air flow into the cylinder 12 to increase the combustion speed and promote combustion. The airflow in the cylinder 12 is strengthened as the airflow control valve 41 is rotated in the closing direction.
[0059]
The flowchart of FIG. 10 shows only processing different from the first embodiment in the start-up control routine executed by the ECU 35. The ECU 35 calculates the target opening degree of the airflow control valve 41 in step 190 after performing the process of step 180. For this calculation, for example, a map shown in FIG. 11 is used. In this map, in the temperature region where the coolant temperature THW is equal to or higher than a predetermined value THW1 (for example, 0 ° C.), the opening degree of the airflow control valve 41 is set to a certain value α on the open side. In the temperature region where the cooling water temperature THW is lower than the predetermined value THW1 (0 ° C.), the opening degree of the airflow control valve 41 is set to a closed value so as to strengthen the airflow as the cooling water temperature THW decreases. In step 190, when the opening degree corresponding to the coolant temperature THW read in step 110 is calculated based on the map, a series of processes in the start-up control routine is temporarily ended.
[0060]
The opening calculated as described above is used as a command value for controlling the actuator 43 in another routine. The airflow control valve 41 is adjusted to the opening degree by the control of the actuator 43. Therefore, the final ignition timing SAfin is set to a retarded value as the cooling water temperature THW decreases (see FIG. 6), but the airflow control valve 41 is closed accordingly, and a strong airflow is generated in the cylinder 12. Will occur. In addition to the airflow control valve 41 and the actuator 43 described above, the airflow control means is configured by the ECU 35 and the like that perform the opening calculation processing in the step 190 and the control processing of the actuator 43 based on the opening.
[0061]
According to the said 2nd Embodiment, in addition to (1) and (2) mentioned above, the following effects are also acquired.
(3) As for the final ignition timing SAfin in step 180, the larger the retard correction amount, the slower the combustion and the greater the smoke reduction effect. However, if the retard amount is excessively increased and the ignition timing is retarded by a predetermined crank angle (about 12 ° CA) or more than the compression top dead center at the time of starting, combustion becomes too slow and the output torque may decrease. is there. Due to this decrease, there is a concern that problems such as difficulty in securing the same output torque as in the case of not performing the retardation correction, and an increase in combustion fluctuation (rotational fluctuation) may occur. The one-dot chain line in FIG. 12 shows the heat generation rate when the final ignition timing SAfin is excessively retarded during cranking (large retard side ignition). When the final ignition timing SAfin is greatly retarded by increasing the retardation correction amount in this way, the final ignition timing SAfin is appropriately retarded as shown by the broken line in FIG. Compared to the embodiment), the combustion becomes slower.
[0062]
On the other hand, in the second embodiment, the airflow control valve 41 is controlled to the closed side as a means for increasing the combustion speed when the retardation is corrected by a predetermined angle (about 12 ° CA) or more than the compression top dead center. . By this control, the air-fuel mixture is turbulent in the cylinder 12 to strengthen the air flow and increase the combustion speed of the air-fuel mixture. The slow combustion is accelerated as shown by the solid line in FIG. It is possible to ensure the same output torque as in the case of no. According to the experiment, if the opening degree control of the air flow control valve 41 is up to about 20 ° CA after the compression top dead center, the same effect as the first embodiment can be obtained, that is, the same level of output. It turns out that torque can be obtained. Thus, according to the second embodiment, the output torque can be ensured while suppressing the combustion field from becoming high temperature.
[0063]
(4) Since the retardation correction amount is increased as the cooling water temperature THW decreases, the combustion speed decreases as the cooling water temperature THW decreases. On the other hand, in 2nd Embodiment, the airflow control valve 41 is controlled to the close side, so that the retardation correction amount increases. For this reason, the degree of airflow application by the airflow control valve 41 is strengthened as the retardation correction amount increases. By strengthening the airflow in this way, fuel vaporization is promoted and the above-described decrease in the combustion speed is compensated, and output torque comparable to that in the case of not performing the retardation correction can be ensured regardless of the coolant temperature THW. .
[0064]
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIGS. The third embodiment differs from the first embodiment in that the ignition timing is further retarded when the engine speed during cranking (cranking rotational speed) is reduced in addition to the engine temperature. ing.
[0065]
The flowchart of FIG. 13 shows only processing different from the first embodiment in the start-up control routine executed by the ECU 35. After the processing of step 140, the ECU 35 calculates the correction amount SAcrnk of the ignition timing for the cranking speed reduction by the processing of steps 150, 160, and 170. Specifically, in step 150, it is determined whether or not the starter is turned on based on a starter signal output in response to the operation of the starter switch 33. That is, it is determined whether or not the driver has turned on the starter by operating the starter switch 33 in order to start the engine 11.
[0066]
If the determination condition of step 150 is satisfied, the correction amount SAcrnk is calculated in step 160 as follows. First, a cranking rotational speed (hereinafter referred to as a predicted rotational speed) NEcrnkbase in a case where there is no decrease due to the type, amount, or foreign matter of the lubricating oil is predicted based on the engine information. As the engine information here, for example, the coolant temperature THW can be cited. A battery voltage may be used instead of or in addition to the cooling water temperature THW.
[0067]
Next, a ratio between an actual cranking rotational speed (hereinafter referred to as an actual rotational speed) NEcrnk detected by the crank angle sensor 31 and the predicted rotational speed NEcrnkbase is obtained. Then, a correction amount SAcrnk is calculated based on this ratio (NEcrnk / NEcrnkbase) and the predicted rotational speed NEcrnkbase.
[0068]
For this calculation, for example, a map shown in FIG. 14 is used. In this map, when the ratio (NEcrnk / NEcrnkbase) is equal to or greater than 1, that is, when the actual rotational speed NEcrnk is equal to or higher than the predicted rotational speed NEcrnkbase, it is considered unnecessary to correct the ignition timing by the correction amount SAcrnk. The correction amount SAcrnk is set to “0”. When the ratio (NEcrnk / NEcrnkbase) is smaller than 1, that is, when the actual rotational speed NEcrnk is lower than the predicted rotational speed NEcrnkbase, the correction amount SAcrnk increases toward the retard side as the predicted rotational speed NEcrnkbase decreases. Is set to Then, after calculating the correction amount SAcrnk based on the map in step 160, the process proceeds to step 180 described above.
[0069]
When cranking is started and the engine speed NE increases after the first explosion, the starter is turned off, so that the determination condition of step 150 is not satisfied. In this case, the process proceeds to step 170, the correction amount SAcrnk is set to “0”, and the process proceeds to step 180. Therefore, the ignition timing correction after the starter is off is only correction based on the engine temperature (correction using the correction amount SAtemp).
[0070]
In step 180, the final ignition timing SAfin is calculated based on the basic ignition timing SAbase, the correction amount SAtemp, and the correction amount SAcrnk obtained in steps 130, 140, 160, and 170, respectively. For example, the correction amounts SAtemp and SAcrnk are added to the basic ignition timing SAbase, and the addition result is used as the final ignition timing SAfin. The calculated final ignition timing SAfin is a further retarded value than in the first embodiment.
[0071]
Therefore, according to the third embodiment, in addition to the above (1) and (2), the following effects can also be obtained.
(5) The actual rotational speed NEcrnk can change due to various causes. For example, the actual rotational speed NEcrnk decreases due to the type and amount of the lubricating oil or contamination of foreign matter. Thus, in the situation where the actual rotational speed NEcrnk is reduced, the moving speed of the piston 13 is slower than a certain combustion speed, so that combustion is performed on the top dead center side and a lot of heat is generated, and the combustion temperature becomes high. End up. That is, when the actual rotational speed NEcrnk is slow, the combustion temperature increases and the amount of smoke generated tends to increase. In particular, since the engine speed NE is low at the time of cranking, the combustion temperature is greatly affected even by a small decrease in rotation.
[0072]
In contrast, in the third embodiment, when the actual rotational speed NEcrnk decreases, the ignition timing is retarded by the correction amount SAcrnk. For this reason, even when the actual rotational speed NEcrnk decreases, by slowing down the combustion, the combustion temperature rises to suppress the combustion field from becoming high temperature, and the same actual rotational speed NEcrnk does not decrease. The generation of smoke can be suppressed to a certain extent.
[0073]
(6) In addition to the correction amount SAtemp based on the coolant temperature THW in the first embodiment, the basic ignition timing SAbase is corrected by the correction amount SAcrnk based on the decrease in the actual rotational speed NEcrnk. For this reason, it is possible to increase the accuracy of the retardation correction as compared with the case where the basic ignition timing SAbase is corrected by the correction amount SAtemp alone. This leads to more effective suppression of smoke generation during cold start.
[0074]
(7) When the starter is turned on, the predicted rotational speed NEcrnkbase predicted based on the engine information is compared with the actual rotational speed NEcrnk. By this comparison, it is possible to reliably detect a decrease in the actual rotational speed NEcrnk and accurately determine whether or not the ignition timing needs to be retarded.
[0075]
(8) After the cranking, the correction amount SAcrnk is set to “0” so that the ignition timing is not corrected according to the decrease in the actual rotational speed NEcrnk. For this reason, it is possible to prevent the ignition timing from being retarded unnecessarily after cranking.
[0076]
(Fourth embodiment)
Next, a fourth embodiment embodying the present invention will be described with reference to FIGS. Unlike the first to third embodiments (see FIG. 15A), in which the engine 11 of the fourth embodiment has one spark plug 25 per cylinder, as shown in FIG. Two spark plugs 25a and 25b are provided per cylinder. From this difference, in the engine 11 of the fourth embodiment, spark discharge is performed at two different locations of each cylinder.
[0077]
As the start-up control by the ECU 35, the ignition timing at the start-up is retarded according to the flowchart shown in FIG. However, a larger value than that of the first embodiment is used as the correction amount SAtemp used for calculating the final ignition timing SAfin.
[0078]
Here, in FIGS. 15 (a) and 15 (b), when the flame propagation speed from the ignition source (ignition plug 25) is assumed to be constant, the flame is displayed for a certain period until a predetermined time elapses from ignition. The propagation range R is indicated by a collection of points. 15 (a) and 15 (b), it can be seen that the combustion rate in a certain period increases in the two-point ignition type compared to the one-point ignition type engine. On the other hand, FIG. 16 shows each heat generation rate when the one-point ignition is performed (see the two-dot chain line) and when the two-point ignition is performed (see the solid line). From FIG. 16, it can be seen that in the two-point ignition, combustion with high heat generation is performed in a short period of time compared to the one-point ignition, and the combustion field is likely to become high temperature. Therefore, in order to suppress the high temperature of the combustion field, a large value is used as the correction amount SAtemp as described above. The two spark plugs 25a and 25b are simultaneously ignited according to the final ignition timing SAfin calculated using this large correction amount SAtemp.
[0079]
Therefore, according to the fourth embodiment, in addition to the above (1) and (2), the following effects can also be obtained.
(9) When the coolant temperature THW is low, the two ignition timings at the time of cranking are both set after the compression top dead center. Therefore, even in a two-point ignition type engine, the ignition timing is retarded after the compression top dead center, so that the combustion becomes slow and the increase in the combustion temperature is suppressed. As a result, as in the first embodiment, it is possible to suppress the occurrence of smoke associated with the high temperature of the combustion field.
[0080]
(10) In the two-point ignition, compared with the one-point ignition, the combustion rate in a certain period is increased, combustion with high heat generation is performed in a short period, and the combustion field is likely to become high temperature. On the other hand, in the fourth embodiment, the ignition timing retardation correction amount is set larger than that in the case of one-point ignition. With this setting, heat generation due to an increase in the combustion rate due to two-point ignition can be suppressed, and smoke generation can be suppressed as in the first embodiment.
[0081]
(Fifth embodiment)
Next, a fifth embodiment embodying the present invention will be described with reference to FIGS. In the fifth embodiment, the ignition timings of the two spark plugs 25 are retarded to different timings. In other words, in the fifth embodiment, a time difference is provided for the two ignition timings after the retardation correction.
[0082]
As the starting control by the ECU 35, the ignition timing at the starting is retarded according to the flowchart shown in FIG. However, different final ignition timings SAfin are calculated for the first ignition and the second ignition. Here, the first final ignition timing SAfin is retarded more than the compression top dead center (large retard side ignition). At this time, the combustion becomes very slow and the output torque decreases. However, by setting the second final ignition timing SAfin slightly later than that, the combustion speed in the middle stage of combustion is promoted and the output torque can be secured. It becomes possible.
[0083]
Therefore, according to the fifth embodiment, in addition to the above (1), (2), (9), and (10), the following effects can also be obtained.
(11) The ignition timings of the two spark plugs 25a and 25b are set to different timings after the compression top dead center. For this reason, for example, a flame associated with the first ignition at the spark plug 25a propagates, and a flame associated with the second ignition at the ignition plug 25b begins to propagate while the range R is expanding. Along with the combustion due to this propagation, heat is generated in the manner shown by the solid line in FIG. As described above, when the final ignition timing SAfin is greatly retarded when the engine temperature is low (large retard side ignition), the final ignition timing SAfin is appropriately retarded as shown by the broken line in FIG. Compared to the case (retarded ignition, corresponding to the first embodiment), the combustion is further slowed down, and heat is generated as shown by the one-dot chain line in FIG. On the other hand, in the fifth embodiment, it is possible to improve the heat generation in the middle stage of combustion and improve the combustion speed by starting the combustion accompanying the ignition of the second point in the early stage of the combustion by the ignition of the first point. . As a result, the combustion is stably performed as in the second embodiment described above, and the smoke can be reduced by lowering the combustion temperature while ensuring the output torque.
[0084]
(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to FIG. In the sixth embodiment, the number of ignition plugs (ignition number) that is the target of the ignition delay is switched according to the engine temperature (cooling water temperature THW).
[0085]
The flowchart of FIG. 19 shows only processing different from the first embodiment in the start-up control routine executed by the ECU 35. After the processing of step 110, the ECU 35 sets the number of ignitions according to the coolant temperature THW in step 120. For this setting, a determination value β for the engine temperature when switching the number of ignitions is set in advance. This determination value β is set to 0 ° C. when the surplus fuel in the cylinder 12 increases and the amount of smoke generated increases rapidly as the engine temperature decreases, for example, when the cooling water temperature THW is the engine temperature. Yes.
[0086]
In step 120, it is determined whether the engine temperature read in step 110 is equal to or lower than the determination value β. When the engine temperature is equal to or lower than the determination value β, the number of ignitions is one. When the engine temperature is higher than the determination value β, the number of ignitions is two. The number of ignitions set here is the target of the ignition delay. Then, after the processing of step 120, the processing after step 130 described above is performed.
[0087]
Therefore, according to the sixth embodiment, in addition to the above (1) and (2), the following effects can also be obtained.
(12) In the two-point ignition, compared with the one-point ignition, the combustion rate in a certain period is increased, combustion with high heat generation is performed in a short period, and the combustion field tends to become high temperature.
[0088]
In this regard, in the sixth embodiment, when the coolant temperature THW is equal to or lower than the determination value β, the ignition at the time of cranking is made one place, and the ignition timing at this time is set after the compression top dead center. Accordingly, the combustion becomes slow as in the first embodiment described above. As a result, it is possible to suppress an increase in the combustion temperature and to suppress the generation of smoke accompanying the increase in the temperature of the combustion field. In addition, when the coolant temperature THW is higher than the determination value β and a normal temperature start in which a small amount of fuel is injected, ignition is performed at two locations during cranking. For this reason, combustion efficiency can be raised and fuel consumption can be improved.
[0089]
Note that the present invention can be embodied in another embodiment described below.
As the air flow control valve 41, a type different from that shown in FIG. 9 may be used. An example is shown in FIG. The air flow control valve 41 is disposed in the vicinity of the upstream of the bifurcated portion in the intake passage 17 connected to each cylinder 12, and is rotatably supported by the shaft 42. By rotating the air flow control valve 41 to the closed side, the flow of the intake air is disturbed, and this flows into the cylinder 12 through the branch portion. For this reason, it is possible to provide an air flow in the cylinder 12 as in the second embodiment.
[0090]
In the second embodiment, the control for applying the air flow by operating the air flow control valve 41 to the closed side is performed when the ignition timing is retarded by a predetermined angle (about 12 ° CA) from the compression top dead center. Also good. In this way, since the combustion speed increases, it is possible to widen the possible retard range of the ignition timing, further reducing smoke and ensuring startability. Further, the above control may be performed when the engine is started and when the engine rotation speed NE is increased after the first explosion.
[0091]
In the third embodiment, the ignition timing retardation correction using the correction amount SAcrnk may be performed as described above even when the engine rotational speed NE increases after cranking.
In the third embodiment, the actual rotational speed NEcrnk and the predicted rotational speed NEcrnkbase may be compared, and it may be determined that the cranking rotational speed has decreased when the former is lower than the latter.
[0092]
In the third embodiment, when the actual rotational speed NEcrnk is lower than the predicted rotational speed NEcrnkbase, the correction amount SAcrnk is calculated based only on the predicted rotational speed NEcrnkbase regardless of the deviation between the two. In this regard, the correction amount SAcrnk may be calculated in consideration of the difference between the actual rotational speed NEcrnk and the predicted rotational speed NEcrnkbase.
[0093]
The fourth to sixth embodiments can also be applied to a multi-point ignition type internal combustion engine that performs spark discharge at three or more locations per cylinder.
(I) It is an essential requirement to retard the final ignition timing SAfin according to the engine temperature (corresponding to the first embodiment). Further, one or more of the following (ii) to (iv) may be combined with the requirement (i).
(Ii) Applying an air flow into the cylinder 12 by controlling the air flow control valve 41 or the like.
(Iii) The final ignition timing SAfin is corrected to be retarded as the actual rotational speed NEcrnk decreases.
(Iv) Perform multiple ignitions.
[0094]
When (iv) is combined, any one of simultaneous ignition, providing a time difference in the ignition timing, and switching the number of ignitions according to the engine temperature is selected and executed. The
[0095]
The present invention is not limited to the in-cylinder injection type gasoline engine but can be applied to a gasoline engine that injects fuel into an intake passage (intake port).
In addition, the technical ideas that can be grasped from the respective embodiments will be described together with their effects.
[0096]
(A) In the start control device for a spark ignition type internal combustion engine according to claim 3, the airflow control means includes an airflow control valve provided in an intake passage, and the airflow control valve increases as the retardation correction amount increases. Is operated to the closed side.
[0097]
According to said structure, an airflow is generated in a cylinder by the action | operation to the close side of an airflow control valve. The airflow is strengthened as the amount of operation of the airflow control valve toward the closing side increases. Accordingly, although the combustion becomes slow as the ignition timing retardation correction amount increases, a decrease in the combustion speed due to this can be compensated by airflow enhancement.
[0098]
(B) In the start control device for a spark ignition internal combustion engine according to any one of claims 1 to 3 and (A), a speed decrease for detecting a decrease in cranking rotational speed of the spark ignition internal combustion engine. A detection means;
The ignition timing control means increases the retard correction amount of the ignition timing in response to the detection of the speed drop by the speed drop detection means.
[0099]
This speed reduction detecting means is constituted by an ECU 35 that determines whether or not the ratio (NEcrnk / NEcrnkbase) is smaller than 1 in step 160 (see FIG. 13) of the third embodiment.
[0100]
According to the above configuration, when the cranking rotational speed decreases due to the type, amount, foreign matter, etc. of the lubricating oil, and this is detected by the speed decrease detecting means, the ignition timing is further retarded by the ignition timing control means. It is corrected. For this reason, the problem that the combustion temperature increases due to a decrease in the cranking rotation speed and smoke is generated can be solved by the retardation correction of the ignition timing.
[0101]
(C) In the spark ignition type internal combustion engine start control device according to (B), the speed reduction detecting means predicts the cranking rotational speed based on the engine information of the spark ignition type internal combustion engine, A decrease in the cranking rotational speed is detected when the ranking rotational speed is lower than the predicted cranking rotational speed.
[0102]
According to the above configuration, the speed reduction detecting means predicts the cranking rotation speed based on the engine information when there is no reduction due to the type, amount, contamination, etc. of the lubricating oil. Then, the actual cranking rotation speed is compared with the predicted cranking rotation speed. By making a comparison in this way, it is possible to reliably detect a decrease in the cranking rotational speed and accurately determine whether or not the ignition timing needs to be retarded.
[0103]
(D) The spark ignition type internal combustion engine start control apparatus according to claim 5, wherein the ignition timing control means determines an ignition timing for at least one ignition and an ignition timing for other ignition when the engine temperature is low. It is something that makes it different.
[0104]
According to the above configuration, for example, while heat is slowly generated by a predetermined ignition, heat is rapidly generated by another ignition, so that the combustion temperature is reduced without reducing the output torque, and the smoke is smoked. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing the configuration of a start control device according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure for retarding ignition timing at engine start.
FIG. 3 is an explanatory diagram showing a tendency that the starting injection amount q increases as the cooling water temperature THW decreases.
FIG. 4 is a schematic diagram showing a map structure of a map used for determining a basic ignition timing SAbase.
FIG. 5 is a schematic diagram showing a map structure of a map used for determining a correction amount SAtemp.
FIG. 6 is an explanatory diagram showing a tendency that the final ignition timing SAfin is retarded as the coolant temperature THW decreases.
FIG. 7 is an explanatory diagram showing a comparison of the relationship between the heat generation rate and the crank angle when the ignition timing is compression top dead center and when the ignition timing is retarded.
FIG. 8 is an explanatory diagram showing a comparison between the relationship between the coolant temperature THW and the smoke concentration, with and without the ignition timing retard correction.
FIG. 9 is an explanatory diagram showing an airflow control valve and its surroundings according to a second embodiment of the present invention.
FIG. 10 is a flowchart showing a part of a procedure for controlling the air flow control valve to the closed side in addition to the retard control of the ignition timing at the time of starting the engine.
FIG. 11 is a schematic diagram showing a map structure of a map used for determining the opening degree of the airflow control valve.
FIG. 12 is an explanatory diagram showing a comparison of the relationship between the heat generation rate and the crank angle when the ignition timing is retarded and when the airflow is enhanced by the airflow control valve in addition to the retard correction.
FIG. 13 is a flowchart showing a part of a procedure for retarding the ignition timing when the cranking rotational speed is lowered according to the third embodiment of the present invention.
FIG. 14 is a schematic diagram showing a map structure of a map used for determining a correction amount SAcrnk.
15A and 15B are views for explaining a fourth embodiment of the present invention, wherein FIG. 15A is an explanatory view showing a combustion state of a one-point ignition engine, and FIG. 15B is a combustion of a two-point ignition engine. It is explanatory drawing which shows a state.
FIG. 16 is an explanatory diagram showing a comparison of the relationship between the heat generation rate and the crank angle for one-point ignition and two-point ignition.
FIG. 17 is an explanatory diagram showing a combustion state when two-point ignition is performed at different times after compression top dead center in the fifth embodiment of the present invention.
FIG. 18 is an explanatory diagram showing a comparison of the relationship between the heat generation rate and the crank angle when the ignition timing is retarded and when two-point ignition is performed at different timings after the compression top dead center.
FIG. 19 is a flowchart showing a part of a procedure for switching and controlling the number of ignitions when the engine is started in the sixth embodiment of the present invention.
FIG. 20 is an explanatory view showing another aspect of the airflow control valve in the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Cylinder (cylinder), 41 ... Airflow control valve (airflow control means), 43 ... Actuator (airflow control means), ECU (ignition timing control means, airflow control means), NEcrnk ... Actual Rotational speed (cranking rotational speed), NEcrnkbase ... predicted rotational speed (cranking rotational speed), THW ... cooling water temperature (engine temperature), SAtemp, SAcrnk point correction amount, SAbase ... basic ignition timing, SAfin ... final ignition timing.

Claims (7)

Is applied to a spark ignition type internal combustion engine, engine temperature or engine temperature based on the engine information corresponding thereto is corrected retarding the definitive ignition timing after the compression top dead center during a period including the initial explosion of the engine cranking when low A starting control device for a spark ignition internal combustion engine, comprising ignition timing control means. 2. The spark ignition type internal combustion engine start control device according to claim 1, further comprising an air flow control unit that applies an air flow to an air-fuel mixture in a cylinder when the ignition timing is retarded. The ignition timing control means increases the retard correction amount of the ignition timing as the engine temperature is low, and the airflow control means increases the airflow of the mixture as the retard correction amount increases. The start control device for a spark ignition type internal combustion engine according to claim 2. The ignition timing control means further increases the retard correction amount of the ignition timing as the cranking rotational speed of the spark ignition type internal combustion engine decreases. A starting control device for a spark ignition type internal combustion engine. The spark ignition internal combustion engine is a multiple point ignition internal combustion engine that performs spark discharge at different locations in the same cylinder,
The spark ignition internal combustion engine according to any one of claims 1 to 4, wherein the ignition timing control means sets the ignition timing of all points at the time of cranking after the compression top dead center when the engine temperature is low. Engine start control device. The spark ignition internal combustion engine is a multiple point ignition internal combustion engine that performs spark discharge at different locations in the same cylinder,
5. The ignition timing control means according to claim 1, wherein when the engine temperature is low, the ignition timing is set at one point during cranking, and the ignition timing at this time is set after the compression top dead center. A start-up control device for a spark ignition type internal combustion engine. The start control device for a spark ignition type internal combustion engine according to any one of claims 1 to 6, wherein the spark ignition type internal combustion engine is an in-cylinder injection type internal combustion engine that directly injects fuel into a cylinder.

Images