JP4099755B2 - Start control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a start control device for an internal combustion engine that rotates and drives a crankshaft by generating expansion stroke combustion by injecting and igniting fuel into a cylinder in an expansion stroke when starting the internal combustion engine. .
[0002]
[Prior art]
In recent years, some internal combustion engines mounted on vehicles employ an engine automatic stop / start device (so-called idling stop device) for the purpose of reducing fuel consumption, reducing exhaust emissions, and reducing noise. This automatic engine stop / start device, for example, automatically stops the engine when the driver stops the vehicle, and then the driver tries to start the vehicle (for example, accelerator pedal depression operation). When starting, the starter is energized and the engine is automatically restarted. For this reason, when driving in an urban area where the frequency of stopping is high, the number of times the starter is driven increases, and the load applied to the starter and the battery increases.
[0003]
As a countermeasure, when the engine is automatically started, fuel is injected into the cylinder stopped in the expansion stroke and ignited to generate expansion stroke combustion, and the crankshaft is rotated by the combustion pressure of the expansion stroke combustion. It has been proposed to start the engine without using a starter by driving (cranking) or to assist the power of the starter. However, depending on the crank angle at the start of the engine (engine start start position), if combustion is simply generated in the cylinder in the expansion stroke, the combustion pressure is insufficient and the minimum torque required for the start (in the compression stroke) (Torque required for a cylinder to overcome compression top dead center) may not be ensured, and starterless starting may be difficult.
[0004]
Therefore, as shown in Japanese Patent Application Laid-Open No. 2002-39038, when the expansion stroke combustion is generated, the exhaust auxiliary valve provided in the cylinder in the compression stroke is opened to reduce the pressure in the cylinder in the compression stroke. By reducing the minimum torque level required for starting, or by increasing the combustion pressure of the expansion stroke combustion by supplying high pressure air to the cylinder in the expansion stroke from the high pressure air supply means, It has been proposed to generate a torque that is equal to or greater than the minimum torque required for assistance.
[0005]
Further, as shown in German Patent No. 199595587, when starting the engine, first, the compression stroke combustion is generated in the cylinder stopped in the compression stroke to drive the crankshaft in the reverse rotation, and then the expansion stroke is performed. It has been proposed that the crankshaft is driven to rotate forward by generating expansion stroke combustion. In this case, after the piston of the cylinder in the expansion stroke is pushed up to near the top dead center (TDC) by the reverse rotation of the crankshaft by the compression stroke combustion, the air in the cylinder is compressed, and then the expansion stroke combustion is generated to generate the expansion stroke. Since the combustion pressure of combustion can be increased, a torque greater than the minimum torque required for starting (or assisting starter power) can be generated.
[0006]
[Problems to be solved by the invention]
By the way, in order to generate the above-described expansion stroke combustion and compression stroke combustion when starting the engine, the fuel injection amount is set so that the combustible air-fuel ratio becomes the combustible air-fuel ratio with respect to the air amount of the combustion chamber volume of the cylinder to be burned at that time. Must be set. Therefore, the combustion chamber volume at the start of the start is calculated based on the crank angle at the start of the start (engine start start position), and the fuel injection amount is calculated so that the combustible air-fuel ratio becomes the air amount of the combustion chamber volume. However, even in this case, the fuel injection amount may not be appropriate for the reason described below, and the actual air-fuel ratio may deviate from the combustible air-fuel ratio and normal combustion may not be generated. There is sex.
[0007]
In general, a crank angle sensor that detects a crank angle outputs a pulse signal every time a crankshaft rotates a predetermined crank angle (for example, 30 ° C. A), and therefore the crank angle sensor cannot detect an accurate crank angle.
[0008]
Moreover, even if the output of the crank angle sensor is read at the start of the start, the crank angle at the start of the start (engine start start position) cannot be detected. This is because the relative rotation angle from the reference crank angle (position where the pulse of the cylinder discrimination sensor is generated) can only be determined based on the count value of the output pulse of the crank angle sensor.
[0009]
Accordingly, when the crank angle at the start of engine (engine start start position) is required, the crank angle (engine stop position) at the previous engine stop is stored in the memory, and the stored value is stored at the next start of start. It is used as the crank angle of the engine, but when the engine is stopped, the compression stroke In Since the crankshaft may reversely rotate without the piston of a cylinder getting over the top dead center (TDC), if this reverse rotation occurs, the crank angle stored in the memory (before reverse rotation) Deviation occurs between the crank angle after reverse rotation (the crank angle at the start of starting). Therefore, if the stored value of the crank angle at the previous engine stop is used as it is as the crank angle at the start of the next start (engine start start position), the combustion chamber volume at the start of the start can be accurately calculated. However, there is a possibility that the fuel injection amount calculated based on such a combustion chamber volume is out of the combustible air-fuel ratio range. In addition, in a cylinder stopped in the compression stroke, air in the cylinder is often compressed to a pressure equal to or higher than the atmospheric pressure. Therefore, if the fuel injection amount is calculated on the basis of the atmospheric pressure, the fuel injection amount In many cases, the actual air-fuel ratio deviates in the lean direction and falls out of the combustible air-fuel ratio range.
[0010]
Further, as shown in the above-mentioned Japanese Patent Application Laid-Open No. 2002-39038, a high-pressure air is provided for providing an exhaust auxiliary valve for reducing the pressure in the cylinder in the compression stroke or supplying high-pressure air to the cylinder in the expansion stroke. If the supply means is provided, there is a disadvantage that the structure is complicated and the cost is increased.
[0011]
The present invention has been made in consideration of these circumstances, and therefore, the object of the present invention is normal even when the amount of fuel injection that gives a combustible air-fuel ratio when starting the internal combustion engine cannot be accurately calculated. It is an object of the present invention to provide a start control device for an internal combustion engine that can generate proper combustion, improve startability, and satisfy the demand for cost reduction.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 ignites by injecting fuel into the cylinder in the compression stroke by the compression stroke combustion control means so that the crankshaft is driven in reverse rotation at the beginning of the internal combustion engine. In this way, compression stroke combustion is generated, and after the crankshaft is reversely rotated by this compression stroke combustion, fuel is injected into the cylinder in the expansion stroke by the expansion stroke combustion control means so that the crankshaft is driven to rotate forward. In the start-up control device that generates the expansion stroke combustion by igniting, the split injection is executed to inject the fuel into a plurality of times when the compression stroke combustion is generated.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 ignites by injecting fuel into the cylinder in the compression stroke by the compression stroke combustion control means so that the crankshaft is driven in reverse rotation at the beginning of the internal combustion engine. In this way, compression stroke combustion is generated, and after the crankshaft is reversely rotated by this compression stroke combustion, fuel is injected into the cylinder in the expansion stroke by the expansion stroke combustion control means so that the crankshaft is driven to rotate forward. In the start-up control device that generates the expansion stroke combustion by igniting, the split injection is performed to inject the fuel into a plurality of times when generating the compression stroke combustion. And performing multiple ignition to perform multiple times of ignition It is what I did.
[0014]
In this case, as in claim 2, the number of divided injections and / or the integrated injection amount may be limited by a predetermined upper limit guard value. In this way, the total fuel injection amount divided and injected into the compression stroke cylinder can be limited, and it is possible to prevent excessive fuel injection beyond the fuel injection amount necessary for compression stroke combustion. it can. In addition, when compression stroke combustion or expansion stroke combustion cannot be generated normally, the amount of fuel remaining in the cylinder can be limited when switching to starter start, preventing startability and emission deterioration during starter start. can do.
[0015]
In this case, the upper guard value may be set to a fixed value in order to simplify the arithmetic processing. However, as described in claim 3, the upper limit guard value may be set according to the temperature of the internal combustion engine, the coolant temperature, or temperature information correlated therewith. A guard value may be set. In this way, even if the fuel amount (wet amount) adhering to the cylinder inner wall or the like changes according to the temperature of the internal combustion engine and the fuel injection amount required for the compression stroke combustion changes, the fuel injection amount appropriate for the change is appropriate. An upper guard value can be set.
[0016]
By the way, even if the air-fuel ratio in the cylinder is gradually changed to the rich direction by split injection to make it into the combustible air-fuel ratio range, it is normal if ignition is not performed during the period when the air-fuel ratio in the cylinder is in the combustible air-fuel ratio range. Inability to generate combustion. However, since the combustion chamber volume of the cylinder stopped in the compression stroke is not constant, it is difficult to set the ignition timing by predicting the period during which the air-fuel ratio in the cylinder is in the combustible air-fuel ratio range by split injection.
[0017]
Therefore, the claim Invention 1 Then, when the compression stroke combustion is generated, multiple ignition is performed to perform multiple times of ignition. is doing . In other words, if split injection and multiple ignition are executed in parallel when generating the compression stroke combustion, the combustible air-fuel ratio can be determined without predicting the period during which the air-fuel ratio in the cylinder is in the combustible air-fuel ratio range by split injection. It is possible to ignite and generate combustion during the range. Moreover, while the atomization of the injected fuel is promoted by split injection, ignition can be performed after preheating the ignition portion of the spark plug and the air-fuel mixture around it by multiple ignition, and the ignitability can be further improved.
[0018]
In this case, the claim 4 As described above, it is preferable to execute the multiple ignition with an ignition cycle shorter than the injection cycle of the divided injection. In this way, one or more ignitions can be executed for each divided injection, and ignition is ensured without missing the period when the air-fuel ratio in the cylinder is in the combustible air-fuel ratio range due to the divided injection. be able to.
[0020]
Further, in a system in which the compression shaft combustion is generated at the beginning of the internal combustion engine and the crankshaft is reversely rotated, and then the expansion shaft combustion is generated and the crankshaft is normally rotated, before the crankshaft is sufficiently reversely rotated, That is, if the expansion stroke combustion is generated before the air in the cylinder that has been stopped in the expansion stroke is sufficiently compressed, the compression pressure is insufficient and the combustion pressure of the expansion stroke combustion can be sufficiently increased. Therefore, there is a possibility that the minimum torque necessary for starting (or assisting starter power) cannot be secured.
[0021]
Therefore, the claim 5 As shown in the figure, the reverse rotation of the crankshaft was caused by the occurrence of compression stroke combustion. Until the expansion stroke combustion occurs It is preferable that detection is performed by the reverse rotation detection means, and ignition is performed to generate expansion stroke combustion after a predetermined period has elapsed from the start of reverse rotation of the crankshaft or after the crankshaft has been reversely rotated by a predetermined crank angle. In this way, after the crankshaft is sufficiently reversely rotated and the air in the cylinder that has been stopped in the expansion stroke is sufficiently compressed, the expansion stroke combustion can be generated. The pressure can be increased sufficiently, and a torque exceeding the minimum torque required for starting (or assisting the starter power) can be reliably generated.
[0022]
In this case, the claim 6 As described above, it is preferable to detect the reverse rotation of the crankshaft based on at least one of the output of the crank angle sensor, the in-cylinder pressure, and the ion current. When the crankshaft rotates in the reverse direction, the output of the crank angle sensor changes. Therefore, by monitoring the output of the crank angle sensor, it is possible to detect the reverse rotation of the crankshaft. In addition, when compression stroke combustion occurs, the ionic current detected via the in-cylinder pressure and the spark plug changes according to the compression stroke combustion state. Therefore, if the in-cylinder pressure and ionic current are monitored, the compression stroke combustion Thus, it is possible to accurately detect that the crankshaft is reversely rotated.
[0024]
Also, the above claims 1 to 4 The techniques relating to split injection and multiple ignition for the compression stroke combustion can be applied to the expansion stroke combustion. In other words, split injection is performed when the expansion stroke combustion is generated. In addition, multiple ignition is performed to perform multiple times of ignition. (Claims 7 ), Limiting the number of divided injections and / or the integrated injection amount with a predetermined upper limit guard value (claims) 8 The upper guard value may be set in accordance with the temperature of the internal combustion engine or the coolant temperature or temperature information correlated therewith (claim). 9 ). Also, when generating expansion stroke combustion Execute Multiple ignition may be executed with an ignition cycle shorter than the injection cycle of the split injection. 10 ). In this way, the split injection and multiple ignition for the expansion stroke combustion are also described above. 4 The effect similar to the effect of the divided injection and the multiple ignition for the compression stroke combustion can be obtained.
[0025]
Claims 7 ~ 10 The invention according to the present invention may be applied to a system that generates expansion stroke combustion after the crankshaft is reversely rotated by a motor at the beginning of the internal combustion engine.
[0026]
By the way, depending on the starting start position of the internal combustion engine (crank angle at the time of starting), there is a case where the compression stroke combustion and the expansion stroke combustion cannot be normally generated. In such a case, the unburned gas (HC) As a result, the exhaust emission is deteriorated and the combustion pressure is insufficient, so that the crankshaft cannot be normally rotated reversely or normally and the internal combustion engine fails to start.
[0027]
Therefore , Contract Claim 11 As described above, in the system in which the expansion stroke combustion is generated after the compression stroke combustion is generated at the start of the internal combustion engine, the compression stroke combustion control and the expansion are performed when the start start position of the internal combustion engine is outside the predetermined crank angle range. You may make it prohibit stroke combustion control. In this way, the compression stroke combustion control and the expansion stroke combustion control are executed only when the start position of the internal combustion engine is within a predetermined crank angle range in which the compression stroke combustion and the expansion stroke combustion can be normally generated. It is possible to prevent exhaust emission and startability from deteriorating.
[0028]
In this case, the claim 12 As described above, the predetermined crank angle range for permitting the compression stroke combustion control and the expansion stroke combustion control is such that the cylinder in the expansion stroke at the start of the start of the internal combustion engine has a temperature range from 60 ° C. A to the exhaust valve opening timing (for example, top dead center). It is preferable to set the crank angle range to 130 ° C. A) after the point.
[0029]
In general, after the start-up, the intake valve is opened until the expansion stroke cylinder exceeds about 60 ° C. after top dead center. Therefore, at the start of start-up, the expansion stroke cylinder is more advanced than 60 ° C. after top dead center. In some cases (when the compression stroke cylinder is on the more advanced side than 60 ° C. after bottom dead center), if the compression stroke combustion is generated, the compression stroke combustion occurs with the intake valve opened, There is a risk of a backfire phenomenon in which the compression stroke combustion flame spreads to the intake pipe side. In addition, even if the piston of the expansion stroke cylinder, which is on the advance side from 60 ° C. after the top dead center at the start of starting, is reversely rotated to the vicinity of the top dead center, the compression amount of the cylinder gas in the expansion stroke cylinder is insufficient. There is a possibility that the combustion pressure of the expansion stroke combustion cannot be increased sufficiently and the start-up by the expansion stroke combustion may fail.
[0030]
On the other hand, when the expansion stroke cylinder is at the retarded side relative to the exhaust valve opening timing (for example, 130 ° C. after top dead center) at the start of starting (the compression stroke cylinder is at the retarded side relative to, for example, 130 ° A after bottom dead center) In some cases, the combustion power of the compression stroke combustion is weak, and the crankshaft may not be able to reversely rotate. Further, in the expansion stroke cylinder that is retarded from the exhaust valve opening timing (for example, 130 ° C. after top dead center), there is a possibility that the exhaust valve opens and the exhaust gas flows back into the cylinder. This exhaust gas causes the expansion stroke combustion to become unstable.
[0031]
Accordingly, if the expansion stroke cylinder at the start of start is outside the crank angle range from 60 ° C. A to the exhaust valve opening timing after top dead center, the compression stroke combustion control and the expansion stroke combustion control are prohibited. Various problems described above can be solved.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
<< Embodiment (1) >>
Hereinafter, an embodiment (1) in which the present invention is applied to, for example, a four-cylinder in-cylinder injection engine will be described with reference to FIGS. First, a schematic configuration of the entire engine control system will be described with reference to FIG. An air cleaner 13 is provided at the most upstream portion of the intake pipe 12 of the direct injection engine 11 which is an internal combustion engine of the direct injection type, and a throttle valve 15 driven by a step motor 14 on the downstream side of the air cleaner 13. Is provided. The opening of the throttle valve 15 (throttle opening) is detected by a throttle opening sensor 17.
[0033]
A surge tank 19 is provided on the downstream side of the throttle valve 15, and an intake manifold 20 that introduces air into each cylinder of the engine 11 is connected to the surge tank 19. A first intake passage 21 and a second intake passage 22 are respectively formed in the intake manifold 20 of each cylinder, and the first intake passage 21 and the second intake passage 22 are formed in each cylinder of the engine 11. The two intake ports 23 are connected to each other.
[0034]
An airflow control valve 24 for controlling the swirl flow strength and the tumble flow strength in the cylinder is disposed in the second intake passage 22 of each cylinder. The airflow control valve 24 of each cylinder is connected to a step motor 26 via a common shaft 25, and an airflow control valve sensor 27 that detects the opening degree of the airflow control valve 24 is attached to the step motor 26.
[0035]
A fuel injection valve 28 for directly injecting fuel into the cylinder is attached to the upper part of each cylinder of the engine 11. The fuel sent from the fuel tank (not shown) to the fuel delivery pipe 30 through the fuel pipe 29 is directly injected into the cylinder from the fuel injection valve 28 of each cylinder and mixed with the intake air introduced from the intake port 23. Thus, an air-fuel mixture is formed. A fuel pressure sensor 31 for detecting fuel pressure (fuel pressure) is attached to the fuel delivery pipe 30.
[0036]
Further, an ignition plug (not shown) is attached to the cylinder head of the engine 11 for each cylinder, and the air-fuel mixture in the cylinder is ignited by spark discharge of each ignition plug. Further, the cylinder discrimination sensor 32 generates an output pulse when a specific cylinder (for example, the first cylinder) reaches the intake top dead center, and the crank angle sensor 33 is configured so that the crankshaft of the engine 11 has a constant crank angle (for example, 30). ° C A) An output pulse is generated every rotation. The crank angle and engine speed are detected by these output pulses, and cylinder discrimination is performed. Further, the engine 11 is provided with a water temperature sensor 34 for detecting the coolant temperature and a starter 42 for starting the engine 11 by rotationally driving (cranking) the crankshaft.
[0037]
On the other hand, exhaust gas discharged from each exhaust port 35 of the engine 11 merges into one exhaust pipe 37 via the exhaust manifold 36. An EGR pipe 38 that recirculates a part of the exhaust gas to the intake system is connected between the exhaust pipe 37 and the surge tank 19, and an EGR amount (exhaust gas recirculation amount) is controlled in the middle of the EGR pipe 38. An EGR valve 39 is provided. The accelerator pedal 40 is provided with an accelerator sensor 41 that detects the accelerator opening.
[0038]
Outputs of the various sensors described above are input to an engine control circuit (hereinafter referred to as “ECU”) 16. The ECU 16 is mainly composed of a microcomputer, and executes various engine control programs stored in a built-in ROM (storage medium), so that the fuel injection amount of the fuel injection valve 28 can be changed according to the engine operating state. Control the ignition timing of the spark plug.
[0039]
In addition, the ECU 16 executes an automatic stop control program (not shown) stored in the ROM so that a predetermined automatic stop condition is satisfied during operation of the engine 11 and an engine stop request is generated (driver) When the vehicle is stopped), the engine 11 is automatically stopped.
[0040]
Further, the ECU 16 executes the automatic start control program shown in FIGS. 4 and 5 stored in the ROM, so that when a predetermined automatic start condition is satisfied and the engine start request is generated while the engine 11 is automatically stopped. When the driver performs an operation to start the vehicle, the engine 11 is automatically started. At that time, the ECU 16 executes a starterless start for starting the engine 11 without using the starter 42 as follows.
[0041]
As shown in FIG. 2, first, fuel is injected into a cylinder in the compression stroke at the beginning of engine start (hereinafter referred to as “compression stroke cylinder”) and ignited to generate compression stroke combustion and reverse the crankshaft. Then, the fuel is injected into a cylinder in an expansion stroke (hereinafter referred to as “expansion stroke cylinder”) and ignited to generate expansion stroke combustion and drive the crankshaft in a normal rotation. As a result, the crankshaft is reversely rotated by the compression stroke combustion to push up the piston of the expansion stroke cylinder to near the top dead center to compress the air in the expansion stroke cylinder, and then the expansion stroke combustion is generated to generate the combustion of the expansion stroke combustion. The pressure is increased, and a torque equal to or higher than the minimum torque required for starting (at least the torque required to overcome the compression top dead center) is generated.
[0042]
Further, as shown in FIG. 3, when the compression stroke combustion is generated, the compression stroke divided injection and the compression stroke multiple ignition are executed for the compression stroke cylinder. In the compression stroke division injection, for example, after the injection of a half of the fuel injection amount Q1 as the initial injection, the injection of 1/10 of the fuel injection amount Q1 is repeatedly performed at a predetermined injection cycle, thereby the compression stroke. The air-fuel ratio in the cylinder is gradually changed in the rich direction. On the other hand, in the compression stroke multiple ignition, ignition is repeatedly performed with an ignition cycle shorter than the injection cycle of the compression stroke division injection. By executing the compression stroke multiple ignition in parallel with the compression stroke split injection, the period during which the air-fuel ratio in the compression stroke cylinder gradually changes in the rich direction due to the compression stroke split injection and falls within the combustible air-fuel ratio range is overlooked. It ignites reliably without causing combustion.
[0043]
The processing contents of the automatic start control program shown in FIGS. 4 and 5 executed by the ECU 16 will be described below.
[0044]
The automatic start control program shown in FIGS. 4 and 5 is repeatedly executed at a predetermined cycle while the engine 11 is automatically stopped, and serves as a compression stroke combustion control means and an expansion stroke combustion control means in the scope of claims. When the program is started, first, at step 101, it is determined whether or not an automatic start condition is satisfied and an engine start request is generated. Here, the automatic start condition is that the driver performs an operation to start the vehicle. For example, when the driver depresses the accelerator pedal 40 or the shift range of the automatic transmission is set to the N range ( Alternatively, the automatic start condition is satisfied when the operation is performed from the P range to the D range.
[0045]
If it is determined that the automatic start condition is satisfied (there is an engine start request), it is determined in steps 102 and 103 whether the starterless start execution condition is satisfied. Here, the starterless start execution condition is, for example, that both the following conditions (1) and (2) are satisfied.
(1) The engine stop position (engine start start position) is within a predetermined crank angle range (see FIG. 2) (step 102).
(2) The cooling water temperature is equal to or higher than a predetermined temperature (for example, 70 ° C. or higher), that is, the engine 11 is in a warm-up state with a low cranking resistance (step 103).
[0046]
Here, the condition (1) will be described. In general, after the start-up, the intake valve is opened until the expansion stroke cylinder exceeds about 60 ° C. after top dead center. Therefore, at the start of start-up, the expansion stroke cylinder is more advanced than 60 ° C. after top dead center. In some cases (when the compression stroke cylinder is on the more advanced side than 60 ° C. after bottom dead center), if the compression stroke combustion is generated, the compression stroke combustion occurs with the intake valve opened, There is a risk of a backfire phenomenon in which the compression stroke combustion flame spreads to the intake pipe side. In addition, even if the piston of the expansion stroke cylinder, which is on the advance side from 60 ° C. after the top dead center at the start of starting, is reversely rotated to the vicinity of the top dead center, the compression amount of the cylinder gas in the expansion stroke cylinder is insufficient. There is a possibility that the combustion pressure of the expansion stroke combustion cannot be increased sufficiently and the start-up by the expansion stroke combustion may fail.
[0047]
On the other hand, when the expansion stroke cylinder is at the retarded side relative to the exhaust valve opening timing (for example, 130 ° C. after top dead center) at the start of starting (the compression stroke cylinder is at the retarded side relative to, for example, 130 ° A after bottom dead center) In some cases, the combustion power of the compression stroke combustion is weak, and the crankshaft may not be able to reversely rotate. Further, in the expansion stroke cylinder that is retarded from the exhaust valve opening timing (for example, 130 ° C. after top dead center), there is a possibility that the exhaust valve opens and the exhaust gas flows back into the cylinder. This exhaust gas causes the expansion stroke combustion to become unstable.
[0048]
Therefore, in the determination of the condition (1), the predetermined crank angle range is set to a crank angle range (see FIG. 2) in which the expansion stroke cylinder reaches the exhaust valve opening timing from 60 ° C. after top dead center, and the engine is stopped. Starterless start (compression stroke combustion control and expansion stroke combustion control) is prohibited when the expansion stroke cylinder in the middle (at the start of startup) is outside the crank angle range of 60 ° C. A to exhaust valve opening timing after top dead center I am doing so. The processing in step 102 serves as prohibition means in the claims.
[0049]
If both of the above conditions (1) and (2) are satisfied, the starterless start execution condition is satisfied. If there is a condition that does not satisfy either of the conditions (1) and (2), the starterless start is performed. The execution condition is not satisfied. Note that when the engine 11 is automatically stopped, the piston stop position of the expansion stroke cylinder may be forcibly controlled to be within the predetermined crank angle range. In this case, the condition (1) is omitted. You may do it.
[0050]
If it is determined that the starterless start execution condition is not satisfied, the routine proceeds to step 117 in FIG. 5, where the starter 42 is energized to start the engine 11 by cranking with the driving force of the starter 42.
[0051]
On the other hand, if it is determined in steps 102 and 103 that the starterless start execution condition is satisfied, the starterless start is executed as follows. First, the routine proceeds to step 104, where the fuel injection amount Q1 injected into the compression stroke cylinder and the fuel injection amount Q2 injected into the expansion stroke cylinder are calculated.
[0052]
In this case, the fuel injection amounts Q1 and Q2 are calculated by setting the engine stop position (crank angle at the time of engine stop) obtained from the pulse signal output from the crank angle sensor 33 at the previous engine stop to a nonvolatile memory such as an SRAM of the ECU 16. The engine stop position data is read from the non-volatile memory at the start of the next engine start, the engine stop position is regarded as the engine start start position, and the estimated combustion of the compression stroke cylinder at the start of the start is performed. The chamber volume V1 and the estimated combustion chamber volume V2 of the expansion stroke cylinder are calculated, and the fuel injection amount Q1 is calculated so that the combustible air-fuel ratio becomes equal to the air amount of the estimated combustion chamber volume V1 of the compression stroke cylinder. The fuel injection amount Q2 is calculated so that the combustible air-fuel ratio becomes the air amount of the estimated combustion chamber volume V2 of the cylinder.
[0053]
Thereafter, the routine proceeds to step 105, where a divided injection upper limit guard value for limiting the integrated injection amount of the compression stroke divided injection is calculated. This divided injection upper limit guard value calculates a divided injection upper limit guard value corresponding to the cooling water temperature by searching a map of divided injection upper limit guard values using the cooling water temperature as a parameter. In general, since the cooling water temperature is a parameter reflecting the temperature of the engine 11, the higher the cooling water temperature, the smaller the amount of fuel (wet amount) adhering to the cylinder inner wall and the like, and the smaller the fuel injection amount required for the compression stroke combustion. . For this reason, the map of the divided injection upper limit guard value is set so that the divided injection upper limit guard value decreases as the coolant temperature increases. Note that the divided injection upper limit guard value may be set in accordance with another parameter (for example, oil temperature) correlated with the temperature of the engine 11.
[0054]
After calculating the divided injection upper limit guard value, the routine proceeds to step 106 where the piston of the expansion stroke cylinder is reversely rotated to near the top dead center based on the engine stop position (engine start start position) stored in the nonvolatile memory of the ECU 16. The target reverse rotation crank angle necessary for the calculation is calculated.
[0055]
Thereafter, the process proceeds to step 107 in FIG. 5 to determine whether or not compression stroke combustion control (compression stroke multiple ignition and compression stroke split injection) has started. If it is before the start of the compression stroke combustion control, the routine proceeds to step 108, where the compression stroke multiple ignition is started and ignition is repeatedly executed with an ignition cycle shorter than the injection cycle of the compression stroke divided injection. After this, the routine proceeds to step 109, where a half of the fuel injection amount Q1 is injected as the initial injection of the compression stroke split injection to start the compression stroke split injection, and then the routine proceeds to step 112.
[0056]
On the other hand, if it is determined in step 107 that the compression stroke combustion control has been started, the routine proceeds to step 110, where the integrated injection amount of the compression stroke divided injection is less than or equal to the divided injection upper limit guard value calculated in step 105. It is determined whether or not there is. As a result, if it is determined that the integrated injection amount of the compression stroke division injection is equal to or less than the division injection upper limit guard value, the routine proceeds to step 111, where 1/10 of the fuel injection amount Q1 as the second and subsequent injections of the compression stroke division injection. Then, the process proceeds to step 112. As a result, at the start of the compression stroke combustion control, after ½ of the fuel injection amount Q1 is injected as the initial injection, 1/10 of the fuel injection amount Q1 is set to a predetermined injection cycle (execution cycle of this program). In this way, the compression stroke division injection that repeatedly injects is executed to gradually change the air-fuel ratio in the compression stroke cylinder in the rich direction.
[0057]
By executing the compression stroke multiple ignition in parallel with the compression stroke split injection by the processing of these step 107 to step 111, the air-fuel ratio in the compression stroke cylinder gradually changes in the rich direction to the combustible air-fuel ratio range. Without failing to miss the period, it is ignited reliably to generate compression stroke combustion. The crankshaft is driven in reverse rotation by the combustion pressure of the compression stroke combustion.
[0058]
If it is determined in step 110 that the cumulative injection amount of the compression stroke split injection has exceeded the split injection upper limit guard value, even if the fuel amount in the cylinder is further increased (that is, the air-fuel ratio is made richer). However, it is determined that the compression stroke combustion does not occur, and the routine proceeds to step 117 where the starter 42 is energized and the engine 11 is started with the driving force of the starter 42.
[0059]
When the routine proceeds from step 109 or 111 to step 112, whether or not the compression stroke combustion has occurred and the crankshaft has rotated in reverse is determined by whether or not the crank angle sensor 33 has detected a pulse signal. When the compression stroke combustion occurs, the in-cylinder pressure and the ionic current of the compression stroke cylinder change. Therefore, it is detected by the in-cylinder pressure sensor or the like whether the compression stroke combustion has occurred and the crankshaft has rotated backward. The determination may be made based on the behavior of the ion current detected via the in-cylinder pressure, the spark plug, or the like. The process of step 112 serves as reverse rotation detection means in the claims.
[0060]
If it is determined in step 112 that the crankshaft is not rotating in reverse (compression stroke combustion has not occurred), the program is terminated without performing the subsequent processing. Thereafter, when compression stroke combustion occurs and the crankshaft rotates in the reverse direction, the routine proceeds from step 112 to step 113, where the compression stroke division injection and the compression stroke multiple ignition are completed.
[0061]
Thereafter, the routine proceeds to step 114, where it is determined based on the output of the crank angle sensor 33 whether or not the crankshaft has been reversely rotated by the target reverse rotation crank angle from the start of reverse rotation of the crankshaft. Whether or not the crankshaft has been reversely rotated by the target reverse rotation crank angle depending on whether or not a predetermined time required for the crankshaft to reversely rotate by the target reverse rotation crank angle has elapsed since the start of reverse rotation of the crankshaft. It may be determined.
[0062]
When it is determined in step 114 that the crankshaft is reversely rotated by the target reverse rotation crank angle, it is determined that the air in the expansion stroke cylinder has been sufficiently compressed, and the routine proceeds to step 115 to execute expansion stroke combustion control. Then, multiple ignition is started with respect to the expansion stroke cylinder, and the fuel injection amount Q2 is collectively injected to generate expansion stroke combustion. The crankshaft is driven to rotate forward by the combustion pressure of this expansion stroke combustion. The fuel injection to the expansion stroke cylinder may be performed at a slightly earlier timing.
[0063]
Thereafter, the routine proceeds to step 116, where it is determined whether or not the engine 11 has been rotated at a speed higher than the start determination speed (for example, 200 rpm) within a predetermined time after the expansion stroke combustion control is started. If the engine 11 has not increased its rotation speed over the start determination speed within a predetermined time, it is determined that the starterless start has failed, and after the multiple ignition of the expansion stroke cylinder has been completed, the routine proceeds to step 117, where the starter The engine 11 is started by the driving force of the starter 42 by energizing the engine 42.
[0064]
On the other hand, if the engine 11 rotates at a speed higher than the start determination speed within a predetermined time, it is determined that starterless start is normally completed at this point, and after the multiple ignition of the expansion stroke cylinder is completed, this program Exit.
[0065]
According to the embodiment (1) described above, since the compression stroke split injection is executed when the compression stroke combustion is generated, the fuel amount in the compression stroke cylinder is gradually increased to increase the amount of fuel in the compression stroke cylinder. The air-fuel ratio of the engine can be gradually changed in the rich direction, and normal combustion can be generated by igniting when the air-fuel ratio in the compression stroke cylinder falls within the combustible air-fuel ratio range. For this reason, even when it is not possible to accurately calculate a fuel injection amount that can achieve a combustible air-fuel ratio, normal compression stroke combustion can be generated, and startability can be improved. Moreover, since it is possible to cope with the problem by simply changing the fuel injection method and the ignition method, it is not necessary to add new mechanisms such as an exhaust assist valve and a high-pressure air supply means, and the demand for cost reduction can be satisfied. .
[0066]
In the present embodiment (1), since the integrated injection amount of the compression stroke divided injection is limited by the divided injection upper limit guard value, the total fuel injection amount dividedly injected into the compression stroke cylinder can be limited. Further, it is possible to prevent excessive fuel injection beyond the fuel injection amount necessary for the compression stroke combustion. In addition, if the compression stroke combustion cannot be generated and switching to the normal starter start, the amount of fuel remaining in the cylinder can be limited, and startability and emission at the starter start can be deteriorated. Can be prevented.
[0067]
Further, in the present embodiment (1), since the divided injection upper limit guard value is set according to the coolant temperature of the engine 11, the compression stroke combustion is performed according to the coolant temperature, which is a parameter reflecting the temperature of the engine 11. An appropriate split injection upper limit guard value can be set corresponding to the change in the required fuel injection amount.
[0068]
In the present embodiment (1), when the compression stroke combustion is generated, the compression stroke divided injection and the compression stroke multiple ignition are executed in parallel. Even without predicting the period during which the fuel ratio falls within the combustible air-fuel ratio range, ignition can be performed during the period when the fuel ratio falls within the combustible air-fuel ratio range to generate combustion. In addition, while promoting atomization of fuel by split injection, ignition can be performed after preheating the ignition portion of the spark plug and the air-fuel mixture around it by multiple ignition, and ignitability can be further improved.
[0069]
Further, in the present embodiment (1), since the compression stroke multiple ignition is executed with an ignition cycle shorter than the injection cycle of the compression stroke divided injection, at least one ignition is executed for each divided injection. It is possible to perform ignition reliably without missing the period when the air-fuel ratio in the cylinder is in the combustible air-fuel ratio range by the compression stroke division injection.
[0070]
In the present embodiment (1), after the crankshaft reversely rotates by the target reverse rotation crank angle from the start of reverse rotation of the crankshaft by the compression stroke combustion (or the crankshaft reversely rotates by the target reverse rotation crank angle). Since the multiple ignition for generating the expansion stroke combustion is executed after the required predetermined time elapses, the crankshaft is sufficiently reversely rotated to sufficiently compress the air in the expansion stroke cylinder. After that, the expansion stroke combustion can be generated, the combustion pressure of the expansion stroke combustion can be sufficiently increased, and the torque more than the minimum torque necessary for starting can be surely generated.
[0071]
<< Embodiment (2) >>
In the embodiment (1), in the system that generates the expansion stroke combustion after generating the compression stroke combustion when starting the engine 11, the compression stroke divided injection and the compression stroke multiple ignition are performed when the compression stroke combustion is generated. However, in the embodiment (2) of the present invention shown in FIGS. 6 and 7, in the system that generates the expansion stroke combustion without performing the compression stroke combustion when starting the engine 11, the expansion stroke is performed. When the combustion is generated, the expansion stroke division injection and the expansion stroke multiple ignition are executed.
[0072]
In the present embodiment (2), the ECU 16 executes the automatic start control program shown in FIGS. When this program is started, first, in step 201, it is determined whether or not an automatic start condition is satisfied and there is an engine start request. If it is determined that an automatic start condition is satisfied (engine start request is present), step In 202 and 203, it is determined whether or not a starterless start execution condition is satisfied. The starterless start execution condition is the same as the starterless start execution condition described in the above embodiment (1). (1) The engine stop position (engine start start position) is within a predetermined crank angle range. 2) The cooling water temperature is equal to or higher than a predetermined temperature.
[0073]
Note that when the engine 11 is automatically stopped, the piston stop position of the expansion stroke cylinder may be forcibly controlled to be within the predetermined crank angle range. In this case, the condition (1) is omitted. You may do it.
[0074]
If it is determined that the starterless start execution condition is not satisfied, the routine proceeds to step 214 in FIG. 7, where the starter 42 is energized to start the engine 11 with the driving force of the starter 42.
[0075]
On the other hand, if it is determined in steps 202 and 203 that the starterless start execution condition is satisfied, the starterless start is executed as follows. First, the routine proceeds to step 204, where the estimated combustion chamber volume V2 of the expansion stroke cylinder is calculated based on the engine stop position (engine start start position) stored in the nonvolatile memory such as SRAM of the ECU 16, and this estimated combustion chamber volume. The fuel injection amount Q2 is calculated so that the combustible air-fuel ratio becomes equal to the air amount V2.
[0076]
Thereafter, the routine proceeds to step 205, where a divided injection upper limit guard value for limiting the integrated injection amount of the expansion stroke divided injection is calculated. This divided injection upper limit guard value calculates a divided injection upper limit guard value corresponding to the cooling water temperature by searching a map of divided injection upper limit guard values using the cooling water temperature as a parameter. Note that the divided injection upper limit guard value may be set in accordance with another parameter (for example, oil temperature) correlated with the temperature of the engine 11.
[0077]
Thereafter, the process proceeds to step 206 in FIG. 7 and it is determined whether or not it is before the start of the expansion stroke combustion control (expansion stroke multiple ignition and expansion stroke split injection). If it is before the start of the expansion stroke combustion control, the routine proceeds to step 207, where the expansion stroke multiple ignition is started and ignition is repeatedly performed with an ignition cycle shorter than the injection cycle of the expansion stroke split injection. Thereafter, the process proceeds to step 208, in which an amount half the fuel injection amount Q2 is injected as the initial injection of the expansion stroke split injection to start the expansion stroke split injection, and then proceeds to step 211.
[0078]
On the other hand, if it is determined in step 206 that the expansion stroke combustion control has been started, the routine proceeds to step 209, where the integrated injection amount of the expansion stroke divided injection is less than or equal to the divided injection upper limit guard value calculated in step 205. It is determined whether or not there is. As a result, if it is determined that the integrated injection amount of the expansion stroke division injection is equal to or less than the division injection upper limit guard value, the routine proceeds to step 210, where the injection of the second and subsequent expansion stroke division injections is 1/10 of the fuel injection amount Q2. Then, the process proceeds to step 211. As a result, at the start of the expansion stroke combustion control, after an amount of 1/2 of the fuel injection amount Q2 is injected as the initial injection, an amount of 1/10 of the fuel injection amount Q2 is set to a predetermined injection cycle (the execution cycle of this program) The expansion stroke divided injection that repeatedly injects is executed to gradually change the air-fuel ratio in the expansion stroke cylinder in the rich direction.
[0079]
By executing the expansion stroke multiple ignition in parallel with the expansion stroke split injection by the processing of these step 206 to step 210, the air-fuel ratio in the expansion stroke cylinder gradually changes in the rich direction to the combustible air-fuel ratio range. Without failing to miss the period, the ignition is surely performed to generate the expansion stroke combustion.
[0080]
If it is determined in step 209 that the integrated injection amount of the expansion stroke split injection has exceeded the split injection upper limit guard value, even if the fuel amount in the cylinder is further increased (that is, the air-fuel ratio is made richer). However, it is determined that expansion stroke combustion does not occur, and the routine proceeds to step 214 where the starter 42 is energized and the engine 11 is started with the driving force of the starter 42.
[0081]
When the routine proceeds from step 208 or step 210 to step 211, whether or not the expansion stroke combustion has occurred and the crankshaft has rotated is determined based on whether or not a pulse signal is detected by the crank angle sensor 33. Whether or not the expansion stroke combustion has occurred and the crankshaft has been rotated is determined based on the in-cylinder pressure detected by the in-cylinder pressure sensor or the like, or the behavior of the ion current detected through the spark plug or the like. May be.
[0082]
If it is determined in step 211 that the crankshaft is not rotating (expansion stroke combustion has not occurred), the program is terminated without performing the subsequent processing. Thereafter, when it is determined that expansion stroke combustion has occurred and the crankshaft has rotated, the routine proceeds from step 211 to step 212, where the expansion stroke split injection and the expansion stroke multiple ignition are terminated.
[0083]
Thereafter, the process proceeds to step 213, where it is determined whether or not the engine 11 has been rotated more than the start determination speed (for example, 200 rpm) within a predetermined time after the expansion stroke combustion control is started. If the engine 11 has not increased its rotation speed at the start determination speed or more within a predetermined time, it is determined that the starterless start has failed, and the routine proceeds to step 214 where the starter 42 is energized to drive the starter 42. Start with force.
[0084]
On the other hand, if the engine 11 rotates at a speed higher than the start determination speed within a predetermined time, it is determined that starterless start has been normally completed at that time, and the program is terminated as it is.
[0085]
In the present embodiment (2) described above, since the expansion stroke split injection and the expansion stroke multiple ignition are executed when the expansion stroke combustion is generated, the split injection and the multiple ignition are performed for the compression stroke combustion. The effect similar to the effect of the divided injection and the multiple ignition of the executed embodiment (1) can be obtained.
[0086]
In the present embodiment (2), in the system that generates the expansion stroke combustion without performing the compression stroke combustion when starting the engine 11, the expansion stroke divided injection and the expansion stroke multiple points are generated when the expansion stroke combustion is generated. In the system in which the expansion stroke combustion is generated after the compression stroke combustion is generated when the engine 11 is started, the expansion stroke divided injection and the expansion stroke multiple points are generated when the expansion stroke combustion is generated. You may make it perform a fire.
[0087]
Further, when the compression stroke combustion and the expansion stroke combustion are generated, it is not always necessary to perform the split injection, and the batch injection of fuel and multiple ignition may be performed in combination. Even in the case of batch injection of fuel, it is necessary to ignite when the fuel injected into the cylinder is atomized and the air-fuel ratio in the cylinder falls within the combustible air-fuel ratio range. Even if the atomization time is not taken into consideration, it is possible to generate normal combustion by igniting during the period in which the air-fuel ratio is in the combustible air-fuel ratio range. In addition, the ignitability can be further improved by the fuel atomization promoting effect by split injection and the preheating effect by multiple ignition.
[0088]
In the above embodiments (1) and (2), the divided injection upper limit guard value for limiting the integrated injection amount of the compression stroke divided injection and the expansion stroke divided injection is set according to the cooling water temperature or the like. However, the division injection upper limit guard value may be a fixed value set in advance in order to simplify the arithmetic processing.
[0089]
Further, the number of injections of the compression stroke division injection and the expansion stroke division injection may be limited by the upper limit guard value.
[0090]
<< Embodiment (3) >>
In the above embodiment (1), when the engine 11 is automatically started, after the compression stroke combustion is generated and the crankshaft is rotated in the reverse direction, the expansion stroke combustion is generated and the crankshaft is rotated forward. In the embodiment (3) of the present invention shown in FIG. 8 and FIG. 9, when the engine 11 is automatically started, the expansion stroke combustion is performed after the motor 42a of the starter 42 is reversely rotated to reversely rotate the crankshaft. It is generated and the crankshaft is rotated forward.
[0091]
In the present embodiment (3), as shown in FIG. 8, for example, the starter motor 42a is energized by switching the rotation direction control signal output from the ECU 16 to the starter 42 between the forward rotation side and the reverse rotation side. A switch for switching the direction is switched between the forward direction side and the reverse direction side. When the starter drive signal is output to the starter 42 and energized with the rotation direction control signal switched to the forward rotation side, the starter motor 42a rotates forward. On the other hand, when the starter drive signal is output to the starter 42 and energized with the rotation direction control signal switched to the reverse rotation side, the starter motor 42a rotates in the reverse direction.
[0092]
In the present embodiment (3), the ECU 16 executes the automatic start control program shown in FIG. When this program is started, first, in step 301, it is determined whether or not an automatic start condition is satisfied and there is an engine start request. If it is determined that an automatic start condition is satisfied (engine start request is present), step In 302 and 303, it is determined whether or not a semi-starterless start execution condition is satisfied. The semi-starterless start execution condition is the same as the starterless start execution condition described in the above embodiment (1). (1) The engine stop position (engine start start position) is within a predetermined crank angle range. 2) The cooling water temperature is equal to or higher than a predetermined temperature. Note that when the engine 11 is automatically stopped, the piston stop position of the expansion stroke cylinder may be forcibly controlled to be within the predetermined crank angle range. In this case, the condition (1) is omitted. You may do it.
[0093]
If it is determined that the semi-starterless start execution condition is not satisfied, the process proceeds to step 310, and the starter drive signal is output to the starter 42 and energized with the rotation direction control signal switched to the normal rotation side, and the starter motor 42a is energized. Rotate forward. As a result, the crankshaft is driven to rotate forward (cranking) with the driving force of the starter 42 to start the engine 11.
[0094]
On the other hand, if it is determined in steps 302 and 303 that the semi-starterless start execution condition is satisfied, the semi-starterless start is executed as follows. First, the routine proceeds to step 304, where the estimated combustion chamber volume V2 of the expansion stroke cylinder is calculated based on the engine stop position (engine start start position) stored in the nonvolatile memory such as SRAM of the ECU 16, and this estimated combustion chamber volume. The fuel injection amount Q2 is calculated so that the combustible air-fuel ratio becomes equal to the air amount V2.
[0095]
Thereafter, the routine proceeds to step 305, where a target reverse rotation crank angle required to reversely rotate the piston of the expansion stroke cylinder to near the top dead center based on the current crank angle stop position is calculated.
[0096]
Thereafter, the process proceeds to step 306, and with the rotation direction control signal switched to the reverse rotation side, the starter drive signal is output to the starter 42 and energized to reversely rotate the starter motor 42a. As a result, the crankshaft is reversely driven by the driving force of the starter 42. The processing in step 306 serves as reverse rotation control means in the claims.
[0097]
Thereafter, the process proceeds to step 307, and it is determined whether or not the crankshaft has been reversely rotated by the target reverse rotation crank angle from the start of reverse rotation of the crankshaft. When it is determined in step 307 that the crankshaft has been rotated reversely by the target reverse rotation crank angle, it is determined that the air in the expansion stroke cylinder has been sufficiently compressed, and the flow proceeds to step 308 to execute expansion stroke combustion control. Then, multiple ignition is started with respect to the expansion stroke cylinder, and the fuel injection amount Q2 is collectively injected to generate expansion stroke combustion. The crankshaft is driven to rotate forward by the combustion pressure of the expansion stroke combustion. The fuel injection to the expansion stroke cylinder may be performed at a slightly earlier timing.
[0098]
Thereafter, the process proceeds to step 309, where it is determined whether or not the engine 11 has been rotated at a speed higher than the start determination speed (for example, 200 rpm) within a predetermined time after starting the expansion stroke combustion control. If the engine 11 has not increased its rotation speed at the start determination speed or more within a predetermined time, it is determined that the semi-starterless start has failed, and after the multiple ignition to the expansion stroke cylinder is completed, the process proceeds to step 310. The crankshaft is driven to rotate forward (cranking) with the driving force of the starter 42 and the engine 11 is started.
[0099]
On the other hand, if the engine 11 rotates at a speed higher than the start determination speed within a predetermined time, it is determined that the semi-starterless start is normally completed, and after the multiple ignition to the expansion stroke cylinder is completed, Exit the program.
[0100]
In the present embodiment (3) described above, after the starter motor 42a is rotated in the reverse direction and the crankshaft is driven in the reverse rotation to compress the air in the expansion stroke cylinder, the expansion stroke combustion is generated and the expansion stroke combustion is performed. Since the combustion pressure can be increased, it is possible to stably generate a torque exceeding the minimum torque required for starting by the expansion stroke combustion.
[0101]
In this embodiment (3), the starter motor 42a only reverses the crankshaft by a slight crank angle (a crank angle smaller than 180 ° C.), so that the starter 42 and the battery are compared with the engine start by the starter 42. Can greatly reduce the burden on the machine.
[0102]
In this embodiment (3), the crankshaft is driven in reverse rotation by the starter motor 42a, but a motor dedicated to reverse rotation drive may be provided.
[0103]
In the above embodiments (1) to (3), the present invention is applied to a system that starts the engine 11 by generating compression stroke combustion or expansion stroke combustion when the engine 11 is automatically started. When the engine 11 is manually started by the above operation, the present invention may be applied to a system that starts the engine 11 by generating compression stroke combustion or expansion stroke combustion.
[0104]
Further, in each of the above embodiments (1) to (3), the forward rotation drive (cranking) of the crankshaft at the time of starting is performed only by the combustion pressure of the expansion stroke combustion. The cranking force of the starting device may be assisted by the combustion pressure of the expansion stroke combustion.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an entire engine control system according to an embodiment (1) of the present invention.
FIG. 2 is a diagram for explaining starterless start control of the embodiment (1).
FIG. 3 is a time chart for explaining split injection and multiple ignition in the embodiment (1).
FIG. 4 is a flowchart (part 1) showing the flow of processing of the automatic start control program of the embodiment (1).
FIG. 5 is a flowchart (part 2) showing the flow of processing of the automatic start control program of the embodiment (1).
FIG. 6 is a flowchart (part 1) showing the flow of processing of the automatic start control program of the embodiment (2).
FIG. 7 is a flowchart (part 2) showing the flow of processing of the automatic start control program of the embodiment (2).
FIG. 8 is a schematic configuration diagram of the entire engine control system in the embodiment (3).
FIG. 9 is a flowchart showing the flow of processing of the automatic start control program according to the embodiment (3).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Intake pipe, 15 ... Throttle valve, 16 ... ECU (compression stroke combustion control means, expansion stroke combustion control means, reverse rotation detection means, prohibition means, reverse rotation control means), 28 ... Fuel injection valve 33 ... Crank angle sensor 34 ... Water temperature sensor 37 ... Exhaust pipe 42 ... Starter 42a ... Motor.

Claims (12)

Compression stroke combustion control means for generating compression stroke combustion by injecting and igniting fuel into a cylinder in the compression stroke so as to reversely drive the crankshaft at the beginning of the internal combustion engine;
An expansion stroke in which expansion stroke combustion is generated by injecting and igniting fuel into a cylinder in the expansion stroke so that the crankshaft is reversely rotated by the compression stroke combustion control means and then the crankshaft is driven to rotate forward. In a start control device for an internal combustion engine comprising combustion control means,
The internal combustion engine is characterized in that the compression stroke combustion control means executes split injection for injecting fuel into a plurality of times when generating the compression stroke combustion and performs multiple ignition for performing a plurality of ignitions. Engine start control device.   The start control device for an internal combustion engine according to claim 1, wherein the compression stroke combustion control means limits the number of times of the divided injection and / or the integrated injection amount by a predetermined upper limit guard value.   The start control device for an internal combustion engine according to claim 2, wherein the compression stroke combustion control means sets the upper limit guard value based on the temperature of the internal combustion engine or the coolant temperature or temperature information correlated therewith. The start control device for an internal combustion engine according to any one of claims 1 to 3, wherein the compression stroke combustion control means executes the multiple ignition at an ignition cycle shorter than an injection cycle of the divided injection. Compression stroke combustion control means for generating compression stroke combustion by injecting and igniting fuel into a cylinder in the compression stroke so as to reversely drive the crankshaft at the beginning of the internal combustion engine;
An expansion stroke in which expansion stroke combustion is generated by injecting and igniting fuel into a cylinder in the expansion stroke so that the crankshaft is reversely rotated by the compression stroke combustion control means and then the crankshaft is driven to rotate forward. In a start control device for an internal combustion engine comprising combustion control means,
Comprising reverse rotation detecting means for detecting that the crankshaft is reversely rotated by the compression stroke combustion until the expansion stroke combustion is generated ;
The expansion stroke combustion control means executes ignition for generating the expansion stroke combustion after a predetermined period has elapsed from the start of reverse rotation of the crankshaft or after the crankshaft has reversely rotated by a predetermined crank angle. A start control device for an internal combustion engine characterized by the above. The reverse rotation detection means, the output of the crank angle sensor, cylinder pressure, based on at least one of the ion current according to claim 5, characterized in that for detecting that said crank shaft is reversely rotated A start control device for an internal combustion engine. An internal combustion engine start control device comprising an expansion stroke combustion control means for generating an expansion stroke combustion by injecting and igniting fuel into a cylinder in an expansion stroke when starting the internal combustion engine to drive the crankshaft to rotate In
The expansion stroke combustion control means executes split injection that injects fuel into a plurality of times when generating the expansion stroke combustion, and executes multiple ignition that performs a plurality of times of ignition. Engine start control device. The start control device for an internal combustion engine according to claim 7 , wherein the expansion stroke combustion control means limits the number of divided injections and / or the integrated injection amount with a predetermined upper limit guard value. 9. The start control device for an internal combustion engine according to claim 8 , wherein the expansion stroke combustion control means sets the upper limit guard value according to the temperature of the internal combustion engine or the coolant temperature or temperature information correlated therewith. The internal combustion engine start control device according to any one of claims 7 to 9, wherein the expansion stroke combustion control means executes the multiple ignition at an ignition cycle shorter than an injection cycle of the divided injection. Compression stroke combustion control means for generating compression stroke combustion by injecting and igniting fuel into a cylinder in the compression stroke so as to reversely drive the crankshaft at the beginning of the internal combustion engine;
An expansion stroke in which expansion stroke combustion is generated by injecting and igniting fuel into a cylinder in the expansion stroke so that the crankshaft is reversely rotated by the compression stroke combustion control means and then the crankshaft is driven to rotate forward. In a start control device for an internal combustion engine comprising combustion control means,
Providing a prohibition means for prohibiting the compression stroke combustion control by the compression stroke combustion control means and the expansion stroke combustion control by the expansion stroke combustion control means when the starting start position of the internal combustion engine is outside the predetermined crank angle range. A start control device for an internal combustion engine. Wherein the predetermined crank angle range, in claim 11, characterized in that it is set to a crank angle range cylinder in the expansion stroke at the beginning of startup in the internal combustion engine is 60 ° C. A to the exhaust valve opening timing after the top dead center A start control device for an internal combustion engine as described.

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