JP4197791B2 - Direct injection engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a direct injection engine, and more particularly to a direct injection engine provided with a starting injector in an intake passage.
[0002]
[Prior art]
Today, in the field of gasoline engines for power such as vehicles, a direct injection engine that directly injects fuel into a combustion chamber like a diesel engine has been put into practical use. An injector that injects fuel into the combustion chamber is only boosted by an electric pump at start-up, so the supply fuel pressure is low. Therefore, in the direct injection engine, in addition to the first injector that directly injects the fuel into the combustion chamber, a second injector that injects the fuel into the intake passage is provided, and at the start, the fuel injected into the intake passage is supplied. Some are supplied to the combustion chamber along with air to supplement the fuel.
[0003]
[Problems to be solved by the invention]
By the way, at the time of start-up, as described above, the pressure of the fuel is not sufficiently increased and the amount of fuel wet attached to the piston or the like increases. In addition, when the engine temperature is low, such as during cold start, the fuel wet is less likely to vaporize, which makes it difficult to form an air-fuel mixture in the combustion chamber and spurs leaner combustion air-fuel ratio. As a result, the combustion in the combustion chamber is prolonged, and the air-fuel mixture supplied from the intake passage to the combustion chamber may be ignited before the ignition plug is activated and ignited, making it difficult to start smoothly.
[0004]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a direct-injection engine having good startability by preventing the air-fuel mixture supplied from the intake passage from being ignited before the operation of the spark plug.
[0005]
[Means for Solving the Problems]
  According to the first aspect of the present invention, a first injector that directly injects fuel into the combustion chamber and a second injector that injects fuel into the intake passage that supplies air to the combustion chamber are provided.In addition to the first injector at the start, the fuel and air injected from the second injector into the intake passage are supplied into the combustion chamber.The direct injection engineAn air flow restricting means for restricting the air flow in the intake passage, and operating the air flow restricting means at the start to suppress atomization of fuel due to the air flow;From the second injectorGenerated in the intake passage by the injected fuelA mixture concentration limiting means for limiting the concentration of fuel in the mixture of fuel and air is provided.
[0006]
By limiting the concentration of fuel in the air-fuel mixture in the air intake passage (air mixture concentration), the air-fuel mixture from the air intake passage can be prevented from igniting before the ignition plug is activated, and the engine can be started smoothly. it can.
[0008]
By restricting the air flow in the intake passage, fuel atomization by the air flow can be suppressed, and the mixture concentration in the intake passage can be restricted.
[0009]
  Claim2In the described invention, the air flow restriction means includes a throttle valve provided upstream of the second injector in the intake passage, and throttle valve control means for controlling the throttle valve, and the control means Is set so that the throttle valve is switched to the fully closed state when starting.
[0010]
By using an existing throttle valve, the air flow in the intake passage can be restricted while maintaining the basic structure of the engine.
[0011]
  Claim3In the described invention, the air-fuel mixture concentration limiting means includes a redo determination means for determining whether or not the start is a redo start, and an injector control means for controlling the second injector, and the injector control The means is set so as to reduce the fuel injection amount of the second injector in the case of re-starting.
[0012]
By reducing the fuel injection amount of the second injector in the second and subsequent startups, even if the fuel wet remaining in the intake passage is vaporized, an increase in the mixture concentration can be suppressed. It is possible to prevent the ignitability of the air-fuel mixture supplied from the intake passage to the combustion chamber from increasing.
[0013]
  Claim4In the described invention, a direct injection engine including a first injector that directly injects fuel into a combustion chamber and a second injector that injects fuel into an intake passage that supplies air to the combustion chamber is provided in a second injection engine. Timing adjustment means for delaying the opening timing of the intake valve relative to the end timing of combustion in the combustion chamber at the start of supplying fuel and air injected into the intake passage from the injector into the combustion chamber; Let me.
  The timing adjusting means includes a starter configured to switch the cranking rotational speed, a temperature detecting means for detecting engine temperature, and a starter control means for controlling the starter. The lower the cranking speed, the lower the setting.
[0014]
By delaying the opening timing of the intake valve relative to the combustion end timing in the combustion chamber, the air-fuel mixture supplied from the intake passage to the combustion chamber is ignited before the ignition plug operates. It is possible to prevent starting and to start smoothly.
[0016]
By lowering the cranking speed when the engine temperature is low and combustion is likely to be prolonged due to the attachment of fuel wet in the combustion chamber or leaning of the combustion air-fuel ratio, the intake valve opens from the expansion stroke to the exhaust stroke and then the intake valve opens. As a result, the intake valve opening timing can be delayed with respect to the combustion end timing in the combustion chamber. In addition, by lowering the cranking speed as the engine temperature is lower, it is possible to prevent the cranking speed from being lowered unnecessarily.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 shows a direct injection engine of the present invention. The direct injection engine will be described as a vehicle power engine in the following description. The engine main body 1 has a cylinder head 11 covered over a cylinder block 10, and a piston 12 is slidably held in a cylinder 10 a formed in the cylinder block 10. The reciprocating motion of the piston 12 in the cylinder 10a is converted into the rotational motion of the crankshaft 13 and transmitted to a transmission (not shown). The crankshaft 13 is connected to the starter 3 via the flywheel 14 when the engine is started.
[0020]
A combustion chamber 100 is formed above the piston 12 with the cylinder block 10 and the cylinder head 11 as chamber walls. In the combustion chamber 100, a mixture of fuel and air is combusted, and the piston 12 moves up and down by the explosive force. Move it. The air-fuel mixture is ignited by a spark plug 15 that extends through the cylinder head 11 and protrudes into the combustion chamber 100.
[0021]
Supply of air constituting the air-fuel mixture is performed by the intake passage 101 formed in the cylinder head 11 and the intake pipe 18 connected thereto. Further, exhaust from the combustion chamber 100 is performed by the exhaust passage 102. The cylinder head 11 is provided with an intake valve 16 for switching communication between the intake passage 101 and the combustion chamber 100 and an exhaust valve 17 for switching communication between the exhaust passage 102 and the combustion chamber 100. ing.
[0022]
A flap-like throttle valve 19 is provided in the intake pipe 18 to adjust the air flow in the intake passage 101 according to the opening degree.
[0023]
The fuel constituting the mixture is supplied by two electromagnetic injectors 21 and 22. A first injector (hereinafter referred to as an in-cylinder injector) 21 is provided so as to penetrate the cylinder head 11 and injects fuel into the combustion chamber 100 from the tip nozzle portion. A second injector 22 (hereinafter referred to as an intake pipe injector as appropriate) 22 is provided at a position downstream of the throttle valve 19 in the intake passage 101 so as to penetrate the intake pipe 18. Fuel is supplied from the tip nozzle portion into the intake passage 101. It comes to inject.
[0024]
The fuel supplied to the injectors 21 and 22 is supplied from the in-cylinder injector 21 by boosting the fuel sucked up from the fuel tank 25 in two stages by the low-pressure pump 24 and the high-pressure pump 23, and the intake pipe injector 22 is supplied by the intake pipe injector 22. The fuel is supplied at a lower fuel pressure than the fuel supplied to the in-cylinder injector 21, which has been boosted by the low pressure pump 24. The high-pressure pump 23 is driven by power transmitted from the crankshaft 13 of the engine body 1 via a belt or the like. On the other hand, the low-pressure pump 24 is electrically driven, and fuel is supplied from the low-pressure pump 24 to both the injectors 21 and 22 at the time of starting.
[0025]
Further, an engine control computer 6 for controlling each part of the engine such as the spark plug 15, the throttle valve 19, the injectors 21 and 22 is attached. The engine control computer 6 has a general configuration including a CPU, a RAM, a ROM, etc., and operates a spark plug 15 based on detection signals from various sensors and outputs a control signal to the throttle valve 19. The opening of the throttle valve 19 (throttle opening) is adjusted, the injectors 21 and 22 are energized by a control signal, and the nozzles of the injectors 21 and 22 are opened at a predetermined timing for a predetermined time.
[0026]
Further, the engine control computer 6 includes throttle valve control means 61. The throttle valve control means 61, together with the throttle valve 19, constitutes an air flow restriction means 7 that is a mixture concentration restriction means, and is realized by software of the engine control computer 6 that controls each part of the engine.
[0027]
Sensors that are input to the engine control computer 6 include a mass flow meter 51 that measures the flow rate of air flowing through the intake passage 101, a crank angle sensor 52, an A / F sensor 53, and a cooling that detects an engine cooling water temperature representative of the engine temperature. There is a water temperature sensor 54 and the like. Further, when the driver operates the key 41 at the start, the ignition (IG) on signal and the starter on signal are input to the engine control computer 6, and when the driver depresses the accelerator pedal 42, the amount of depression is input. It is supposed to be.
[0028]
The control in the engine control computer 6 when starting the engine will be described with reference to FIG. In the following procedure, procedures other than steps S101 and S104 are executed in the engine control computer 6.
[0029]
First, when the driver turns the key 41 to IG on (step S101), the process proceeds to step S102, and the injection amount that the in-cylinder injector 21 injects into the combustion chamber 100 at the time of starting (hereinafter referred to as in-cylinder injection amount). And an injection amount that the intake pipe injector 22 injects into the intake passage 101 (hereinafter referred to as an intake pipe injection amount). The in-cylinder injection amount and the intake pipe injection amount are obtained by performing a correction according to the detected temperature of the cooling water temperature sensor 54 on the initial value stored in advance by a known method. Set to a large value.
[0030]
The subsequent step S103 is a procedure as the throttle valve control means 61, prohibiting the throttle valve control in accordance with the depression amount of the accelerator pedal 42, and switching the throttle valve opening to the fully closed state (throttle valve opening minimum).
[0031]
When the driver turns the key 41 to starter on in step S104, the intake pipe injector 22 injects the fuel in the intake pipe 101 into the intake passage 101 in step S105, and in the subsequent step S106, normal start control is performed. I do. That is, the in-cylinder injection amount of fuel is injected from the in-cylinder injector 21 into the combustion chamber 100 at a predetermined timing, and then the air-fuel mixture in the combustion chamber 100 is ignited by the spark plug 15.
[0032]
In a succeeding step S107, it is determined whether or not the start is successful and whether or not the complete explosion is started. The determination is made, for example, by checking whether the engine speed Ne is equal to or higher than a predetermined speed (for example, 400 rpm). If the engine speed Ne exceeds the predetermined speed, it is determined that the engine has been successfully started. If the start is successful, the process proceeds to step S108.
[0033]
In step S108, the prohibition of the control of the throttle valve 19 by the accelerator pedal 42 is canceled, and the normal control after the start is started (step S109).
[0034]
If it is determined in step S107 that the engine has failed, the process proceeds again to step S101 or step S104. That is, when the key 41 is again turned to IG on by the driver (step S101), the process is executed from step S102, and when the key 41 is again turned to starter on (step S104), the process is executed from step S105.
[0035]
In this embodiment, the throttle opening is fully closed at the time of start-up by the starter 3, and the following effects can be obtained with respect to a conventional direct injection engine that may be started by increasing the throttle opening. FIG. 3 shows the operation of the intake pipe injector 22 and the behavior of the air-fuel mixture concentration in the most downstream part (position near the intake valve 16) of the intake passage 101. The direct injection engine of the present embodiment (the present invention) and the conventional one are shown in FIG. The figure also shows a case where the throttle opening is fully open in a direct injection engine (conventional example). In the conventional example, after the fuel injection of the intake pipe injector 22 is started, the mixture concentration rapidly rises and takes a high value. This state continues for more than 1 second, whereas in this embodiment, the mixture concentration is low. The value is much lower than the conventional example. Therefore, the air-fuel mixture concentration in the intake passage 101 is high in the conventional example when the intake valve 16 is opened, but is suppressed to a low value in the present invention.
[0036]
In the conventional example, the strong air flow in the intake passage 101 promotes atomization of the fuel injected into the intake passage 101, whereas in the present invention, since the throttle valve 19 is fully closed, the intake passage It is recognized that the air flow in 101 is weak and the action of atomizing the fuel injected from the intake pipe injector 22 is weak.
[0037]
Thus, in the direct injection engine of the present embodiment, even if combustion in the combustion chamber 100 continues until the intake valve 16 is opened, the air-fuel mixture from the intake passage 101 is prevented from igniting before the operation of the spark plug 15. it can.
[0038]
(Second Embodiment)
FIG. 4 shows a second embodiment of the direct injection engine of the present invention. In the first embodiment, the engine control computer 6A is replaced with another engine control computer 6A. In addition, in the figure, the same number as FIG. 1 is attached | subjected to the part which operate | moves substantially the same as 1st Embodiment.
[0039]
The engine control computer 6A has basically the same configuration as the engine control computer 6 of the first embodiment, and includes a redo determination means 62 and an injector control means 63 that constitute the mixture concentration limiting means 7A. These redo determination means 62 and injector control means 63 are realized on the software of the engine control computer 6A.
[0040]
The control in the engine control computer 6A when starting the engine will be described with reference to FIG. In the following procedure, procedures other than steps S201 and S203 are executed in the engine control computer 6A.
[0041]
First, when the driver turns the key 41 to IG on (step S201), the in-cylinder injection amount and the intake pipe injection amount are calculated (step S202) as in the first embodiment (step S102), and then the starter When turning to ON (step S203), the process proceeds to step S204.
[0042]
Steps S204, S205, and S210 are operating procedures as the redo determination means 62. First, in step S204, the starting frequency parameter i is incremented by one. Here, as will be described later, the start frequency parameter i is set to 0 when the engine control computer 6A is started, that is, at the first start. In a succeeding step S205, it is determined whether the starting frequency parameter i is 1 or 2 or more.
[0043]
If the number-of-starts parameter i is 1, this is the first start, and the process proceeds to step S206, where the intake pipe injector 22 injects the fuel in the intake pipe injection amount calculated in step S202 into the intake passage 101, In subsequent step S208, normal start control is performed in the same manner as in the first embodiment (step S106).
[0044]
In step S209, as in the first embodiment (step S107), it is determined whether the start is successful. If the engine has been successfully started, the process proceeds to step S210, where the start frequency parameter i is set to 0, and the engine control computer 6A is started again after the engine is stopped. Next, the process proceeds to step S211, and the normal control is performed in the same manner as in the first embodiment (step S109).
[0045]
If it is determined in step S209 that the engine has failed, the process proceeds again to step S201 or step S203, and the procedure from the advanced step is executed after the driver's key 41 is operated.
[0046]
In step S205 in the middle, since the starting frequency parameter i is incremented to 2 or more in step S204, it is determined that the starting is to be performed again, and the process proceeds from step S205 to step S207.
[0047]
Step S207 is an operation procedure as the injector control means 63, and is a procedure for operating the intake pipe injector 22. However, the energization time to the intake pipe injector 22 is shortened compared to the first start (step S206), and the intake pipe is reduced. The nozzle open time of the injector 22 is shortened. Accordingly, the fuel is injected into the intake passage 101 at an injection amount that is smaller than that at the time of the first start. The reduced injection amount is set by multiplying the intake pipe injection amount calculated in step S202 by a certain ratio.
[0048]
FIG. 6 shows the most downstream portion of the intake passage 101 (intake air) when fuel is injected from the intake pipe injector 22 in a conventional direct injection engine that is not configured to perform reduced injection in the intake pipe at the time of re-starting. This shows the behavior of the air-fuel mixture concentration in the vicinity of the valve 16, and the first (first start) and the third (second restart start) when the start is performed a total of three times (restart start two times). Are also shown. From the figure, it is known that the air-fuel mixture concentration increases at the start of redoing. This is because a part of the fuel injected into the intake passage 101 remains in the form of fuel wet or the like adhering to the wall surface of the intake passage 101, etc., which is re-evaporated at the time of starting, and the mixture concentration in the intake passage 101 is Perceived to rise.
[0049]
Therefore, in the conventional direct injection engine, the air-fuel mixture concentration in the intake passage 101 becomes high at the time of re-starting, and the air-fuel mixture in the intake passage 101 is easily ignited before the operation of the spark plug 15. In the direct injection engine of the embodiment, since the fuel injection amount of the intake pipe injector 22 is reduced at the start of re-starting, an increase in the air-fuel mixture concentration in the intake passage 101 is suppressed, and combustion in the combustion chamber 100 is continued until the intake valve 16 opens. Even if it is prolonged, it is possible to prevent the air-fuel mixture supplied from the intake passage 101 to the combustion chamber 100 from igniting before the operation of the spark plug 15.
[0050]
Note that the reduction in the fuel injection amount of the intake pipe injector 22 is determined in advance by experiments or the like so as to maintain an appropriate mixture concentration. Of course, the fuel injection amount may be set to 0, that is, in the case of re-starting, fuel may not be injected from the intake pipe injector 22.
[0051]
(Third embodiment)
FIG. 7 shows a third embodiment of the direct injection engine of the present invention. In the first embodiment, the starter 3 is replaced with another starter 3A, and the engine control computer 6 is replaced with another engine control computer 6B. In addition, in the figure, the same number as FIG. 1 is attached | subjected to the part which carries out substantially the same operation | movement as 1st Embodiment.
[0052]
The starter 3A is configured so that the cranking rotation speed can be switched. For the switching, for example, a variable resistor is provided between the motor of the starter 3A and its power supply to change the driving voltage of the motor.
[0053]
The engine control computer 6B basically has the same configuration as the engine control computer of the first embodiment, and performs switching control of the cranking rotation speed (specifically, the resistance value of the variable resistor) of the starter 3A. A starter control means 64 is provided. The starter control means 64 is realized on software of the engine control computer 6A, and constitutes the timing adjustment means 7B together with the coolant temperature sensor 54 and the starter 3A as temperature detection means.
[0054]
The control in the engine control computer 6B when starting the engine will be described with reference to FIG. In the following procedure, procedures other than steps S301 and S304 are executed in the engine control computer 6B.
[0055]
First, when the driver turns the key 41 to IG on (step S301), the in-cylinder injection amount and the intake pipe injection amount are calculated (step S302) as in the first embodiment (step S102). move on.
[0056]
Step S303 is a procedure as the starter control means 64, and calculates the cranking rotation speed based on the temperature detected by the coolant temperature sensor 54. The cranking speed is calculated based on a monotonically decreasing function with respect to the cooling water temperature, and the lower the cooling water temperature, the lower the cranking speed is set. The variable resistor of the starter 3A is set corresponding to the calculated cranking rotation speed.
[0057]
Next, when the driver rotates the key 41 to starter on (step S304), fuel is injected into the intake passage 101 by the intake pipe injector 22 (step S305) as in the first embodiment (steps S105 and S106). ), Normal starting control is performed (step S306). At this time, the engine cycle proceeds at a speed corresponding to the cranking rotational speed calculated in step S303.
[0058]
In step S307, it is determined whether or not the start has been successful as in the first embodiment (step S107). If the start is successful, the routine proceeds to normal control (step S308) as in the first embodiment (step S109). If it is determined in step S307 that the start has failed, the process proceeds again to step S301 or step S304, and the start is restarted after the driver's key 41 is operated.
[0059]
FIG. 9 shows the result of investigating the combustion state in the combustion chamber with the cooling water temperature, etc., under the same conditions, with only the cranking rotation speed being different. (A) is the high rotation speed range (260 rpm), and (B) is low. The rotation speed range (180 rpm). In the figure, “slow combustion” indicates combustion that continues until the intake valve is opened, and “normal combustion” indicates combustion that has been completed before the intake valve is opened. In addition, the horizontal axis shows a leaning tendency with respect to the in-cylinder fuel injection amount. The higher the lean tendency, the longer the combustion time after ignition, but in the figure, slow combustion may occur in the high engine speed range, whereas slow combustion does not occur in the low engine speed range. This is because even if the combustion time is the same, the engine cycle speed from the expansion stroke through the compression stroke to the intake stroke is slow and the time until the intake valve opens is long in the low engine speed range. On the other hand, it is recognized that the time when the intake valve opens is delayed.
[0060]
Further, when the engine temperature is low, the lean tendency tends to be high, and the slow combustion is more likely to occur. Therefore, the cranking rotation speed at which the slow combustion can be avoided becomes low.
[0061]
Therefore, the combustion state is investigated in advance as described above, and the cranking rotational speed obtained as a function used for the calculation of the cranking rotational speed in step S303 is low enough to avoid slow combustion. In addition, the lower the cooling water temperature, the lower the rotation speed.
[0062]
As described above, in the present embodiment, the timing at which the intake valve opens relative to the combustion end timing is delayed, and the air-fuel mixture supplied from the intake passage 101 to the combustion chamber 100 is ignited before the ignition plug 15 is activated. In addition, the cranking rotational speed can be avoided from being unnecessarily lowered on the relatively high temperature side by lowering the cranking rotational speed as the engine temperature is low and the combustion time is likely to be prolonged.
[0063]
Note that the cranking rotation speed may not be obtained by a function with respect to the cooling water temperature, but may be set by referring to this map stored in advance as a one-dimensional map with respect to the cooling water temperature. Further, the starter may be a discontinuous switching type instead of a switching type in which the cranking rotation speed is continuously variable. In this case, the starter may be configured to switch the cranking rotation speed not by switching the drive voltage but by switching the gear ratio.
[0064]
(Fourth form)
  FIG. 10 shows the present invention.Reference exampleDirect injection engineFourth formIndicates. In the first embodiment, the engine control computer 6C is replaced with another engine control computer 6C. In addition, in the figure, the same number as FIG. 1 is attached | subjected to the part which carries out substantially the same operation | movement as 1st Embodiment.
[0065]
The engine control computer 6C has basically the same configuration as the engine control computer of the first embodiment, and includes injector control means 7C as timing adjustment means, which is realized on the software of the engine control computer 6C. Is done.
[0066]
The control in the engine control computer 6C when the engine is started will be described with reference to FIG. In the following procedure, procedures other than steps S401 and S404 are executed in the engine control computer 6C.
[0067]
First, when the driver turns the key 41 to IG on (step S401), the process proceeds to step S402, and the intake pipe injection amount is calculated. Unlike the above-described embodiments, the intake pipe injection amount is set to an amount capable of supplying all the fuel for combustion in the combustion chamber 100. Further, the intake pipe injection amount is set by correcting the initial value stored in advance according to the temperature detected by the coolant temperature sensor 54, and the injection amount becomes larger as the fuel is less liable to vaporize.
[0068]
Subsequent step S403 is a procedure as the injector control means 7C, and is set so that the in-cylinder injection control by the in-cylinder injector 21 is prohibited.
[0069]
When the driver turns the key 41 to starter on in step S404, fuel is injected into the intake passage 101 by the intake pipe injector 22 in step S405, and start control is performed in the subsequent step S406. That is, the air-fuel mixture in the combustion chamber 100 is ignited by the spark plug 15 at a predetermined timing. At this time, only the fuel injected from the intake pipe injector 22 into the intake passage 101 burns.
[0070]
In step S407, similarly to the first embodiment (step S107), it is determined whether or not the start is successful. If the start is successful, the process proceeds to step S408.
[0071]
In step S408, the prohibition of the in-cylinder injection control by the in-cylinder injector 21 is canceled, and the routine proceeds to normal control as in the first embodiment (step S109) (step S409).
[0072]
If it is determined in step S407 that the start has failed, the process proceeds to step S401 or step S404 again, and the start is performed again after waiting for the driver to operate the key 41.
[0073]
  This formThen, at the time of start-up, the injection control by the in-cylinder injector 21 is prohibited, and only the fuel injected into the intake passage 101 is supplied to the combustion chamber 100. Of the fuel injected into the intake passage 101, most of the fuel that becomes wet remains in the intake passage 101 and is supplied to the combustion chamber 100 after the intake valve 16 is opened and rides on the airflow to the combustion chamber. It is atomized fuel that moves into 100. Therefore, there is almost no fuel wet in the combustion chamber 100. Therefore, prolonged combustion in the combustion chamber 100 can be avoided.
[0074]
  in this way,This formIn this direct injection engine, the fuel wet in the combustion chamber 100 is reduced to avoid slow combustion and the timing at which the intake valve 16 opens relative to the combustion end timing is relatively delayed so It is possible to prevent the air-fuel mixture supplied to 100 from being ignited before the ignition plug 15 is activated.
[0075]
(Fifth embodiment)
FIG. 12 shows a fifth embodiment of the direct injection engine of the present invention. In the first embodiment, the engine control computer 6D is replaced with another engine control computer 6D. In addition, in the figure, the same number as FIG. 1, FIG. 4 is attached | subjected to the part which carries out substantially the same operation | movement as 1st, 2nd embodiment.
[0076]
The engine control computer 6D basically has the same configuration as the engine control computer of the first embodiment, and includes a throttle valve control means 61 that constitutes the air flow restriction means 7 together with the throttle valve 19, and an air-fuel mixture concentration restriction means 7A. Are included in the software of the engine control computer 6D.
[0077]
The control in the engine control computer 6D when starting the engine will be described with reference to FIG. In the following procedure, procedures other than steps S501 and S504 are executed in the engine control computer 6D.
[0078]
First, when the driver turns the key 41 to IG on (step S501), the in-cylinder injection amount and the intake pipe injection amount are calculated (step S502) as in the first embodiment (step S102, S103), and the accelerator is operated. Control of the throttle valve according to the depression amount of the pedal 42 is prohibited, and the throttle opening is switched to fully closed (step S503). Step S503 is an operation procedure as the throttle valve control means 61.
[0079]
Next, when the driver rotates the key 41 to the starter on (step S504), the process proceeds to step S505.
[0080]
Steps S505, S506, and S512 are operation procedures as the redo determination means 62, and the same procedures (steps S204, S205, and S210) as in the second embodiment are executed. First, the starting number parameter i is incremented by 1 (step S505), and it is determined whether the starting number parameter i is 1 or 2 or more (step S506).
[0081]
If the number-of-starts parameter i is 1, this is the first start, and the process proceeds to step S507. In the same manner as in the second embodiment (step S206), the intake pipe injector 22 is used to calculate the intake passage 101 in step S502. The amount of fuel injected into the intake pipe is injected. On the other hand, if the number-of-starts parameter i is 2 or more, it means that the engine is restarted, and the process proceeds to step S508, and the injection amount reduced in the intake passage 101 by the intake pipe injector 22 as in the second embodiment (step S207). Inject fuel at.
[0082]
After the intake pipe injection (step S507 or step S508), the normal start control is performed (step S509) as in the first embodiment (step S106).
[0083]
In the subsequent step S510, it is determined whether or not the start has been successful as in the first embodiment (step S107). If the start is successful, the prohibition of the control of the throttle valve 19 by the accelerator pedal 42 is canceled (step S511) as in the first embodiment (step S108), and the start frequency parameter i is determined as in the second embodiment (step S210). Is set to 0 (step S512), and normal control after the start is started (step S513).
[0084]
If it is determined in step S510 that the engine has failed, the process proceeds again to step S501 or step S504, and the procedure from the advanced step is executed after the driver's key 41 is operated.
[0085]
According to the present embodiment, at the time of start-up, the stall valve opening is fully closed to limit the air-fuel mixture concentration in the intake passage 101, and in the case of re-starting, the injection amount of the intake passage injection is reduced. Thus, it is possible to avoid an increase in the air-fuel mixture concentration in the intake passage 101 at the start of redoing. Accordingly, it is possible to prevent the air-fuel mixture supplied from the intake passage 101 to the combustion chamber 100 from being ignited before the ignition plug 15 is actuated.
[0086]
(Sixth embodiment)
FIG. 14 shows a sixth embodiment of the direct injection engine of the present invention. In the first embodiment, the starter 3A is replaced with the starter 3A of the third embodiment, and the engine control computer 6 is replaced with another engine control computer 6E. In the figure, parts that operate substantially the same as those in the first, second, and third embodiments are denoted by the same reference numerals as those in FIGS.
[0087]
The engine control computer 6E basically has the same configuration as the engine control computer of the first embodiment, and includes a throttle valve control means 61 that constitutes an air flow restriction means 7 together with the throttle valve 19, and an air-fuel mixture concentration restriction means 7A. Are provided with starter control means 7B constituting the timing adjusting means 7B together with the starter 3A and the coolant temperature sensor 54, and the starter control means 7B constituting the timing adjustment means 7B. These are realized on the software of the engine control computer 6E. Is done.
[0088]
The control in the engine control computer 6E at the time of engine start will be described with reference to FIG. In the following procedure, procedures other than steps S601 and S605 are executed in the engine control computer 6E.
[0089]
First, when the driver turns the key 41 to IG on (step S601), as in the first embodiment (steps S102 and S103), the in-cylinder injection amount and the intake pipe injection amount are calculated (step S502). Control of the throttle valve according to the depression amount of the accelerator pedal 42 is prohibited, and the throttle valve opening is switched to fully closed (step S603). Step S603 is an operation procedure as the throttle valve control means 61.
[0090]
Next, the cranking rotation speed is calculated (step S604) as in the third embodiment (step S303). Step S604 is an operation procedure as the starter control means 64.
[0091]
Thereafter, when the driver rotates the key 41 to the starter on (step S605), the process proceeds to step S606.
[0092]
Steps S606, S607, and S613 are operation procedures as the redo determination means 62, and the same procedures (steps S204, S205, and S210) as in the second embodiment are executed. First, the starting number parameter i is incremented by 1 (step S606), and it is determined whether the starting number parameter i is 1 or 2 or more (step S607).
[0093]
If the number-of-starts parameter i is 1, this is the first start, and the process proceeds to step S608. In the same manner as in the second embodiment (step S206), the intake pipe injector 22 calculates the intake passage 101 as in step S602. The amount of fuel injected into the intake pipe is injected. On the other hand, if the number-of-starts parameter i is 2 or more, it means restarting, and the process proceeds to step S609, and the injection amount reduced in the intake passage 101 by the intake pipe injector 22 as in the second embodiment (step S207). Inject fuel at.
[0094]
After the intake pipe injection (step S608 or step S609), the normal start control is performed (step S610) as in the first embodiment (step S106). At this time, the speed of the engine cycle is a speed corresponding to the cranking speed set in step S604.
[0095]
In the subsequent step S611, it is determined whether or not the start is successful as in the first embodiment (step S107). When the start is successful, the prohibition of the control of the throttle valve 19 by the accelerator pedal 42 is canceled (step S612) as in the first embodiment (step S108), and the start frequency parameter i is determined as in the second embodiment (step S210). Is set to 0 (step S613), and the control shifts to normal control after starting (step S614).
[0096]
If it is determined in step S611 that the engine has failed, the process proceeds again to step S601 or step S605, and the procedure from the advanced step is executed after the driver's key 41 is operated.
[0097]
According to the present embodiment, at the time of starting, the throttle opening is fully closed to limit the air-fuel mixture concentration in the intake passage 101. In addition, in the case of redoing, the injection amount of the intake pipe injection is reduced. An increase in the air-fuel mixture concentration in the intake passage 101 at the start can be avoided. Further, the cranking speed decreases as the coolant temperature decreases, the timing at which the intake valve 16 opens relative to the combustion end timing is relatively delayed, and slow combustion that continues until the intake valve 16 opens is prevented. It is possible to avoid the cranking rotational speed from being lowered unnecessarily on the relatively high temperature side. Thus, the air-fuel mixture supplied from the intake passage 101 to the combustion chamber 100 can be prevented from being ignited before the ignition plug 15 is activated.
[0098]
In addition, although each said embodiment showed what was applied to the gasoline direct-injection engine for the motive power of a vehicle, it is not necessarily limited to this, Unless it is contrary to the meaning of this invention, it is arbitrary.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a first direct injection engine of the present invention.
FIG. 2 is a flowchart showing the operation of the first direct injection engine of the present invention.
FIG. 3 is a time chart showing the operation of the first direct injection engine of the present invention.
FIG. 4 is a diagram showing a configuration of a second direct injection engine of the present invention.
FIG. 5 is a flowchart showing the operation of the second direct injection engine of the present invention.
FIG. 6 is a time chart showing the operation of the second direct injection engine of the present invention.
FIG. 7 is a diagram showing a configuration of a third direct injection engine of the present invention.
FIG. 8 is a flowchart showing the operation of the third direct injection engine of the present invention.
9A and 9B are graphs for explaining the operation of the third direct injection engine of the present invention, respectively.
FIG. 10 shows the present invention.Reference exampleIt is a figure which shows the structure of a 4th direct injection engine.
FIG. 11 shows the present invention.Reference exampleIt is a flowchart which shows the action | operation of a 4th direct injection engine.
FIG. 12 is a diagram showing a configuration of a fifth direct injection engine of the present invention.
FIG. 13 is a flowchart showing the operation of the fifth direct injection engine of the present invention.
FIG. 14 is a diagram showing a configuration of a sixth direct injection engine of the present invention.
FIG. 15 is a flowchart showing the operation of the sixth direct injection engine of the present invention.

Claims (4)

A direct injection engine and a second injector for injecting fuel and first injector into the intake passage for supplying air to the combustion chamber to inject fuel directly into the combustion chamber, a first injector at start-up in addition, in direct injection engines without to supply fuel and air injected into the intake passage from the second injector combustion chamber, air flow restricting means for restricting the air flow in the intake passage The fuel in the air-fuel mixture is generated in the intake passage by the fuel injected from the second injector by operating the air flow restricting means at the start to suppress atomization of fuel due to the air flow. A direct-injection engine characterized by comprising an air-fuel mixture concentration limiting means for limiting the concentration of fuel. 2. The direct injection engine according to claim 1, wherein the air flow restricting means is composed of a throttle valve provided upstream of the second injector in the intake passage and throttle valve control means for controlling the throttle valve. And a direct injection engine in which the throttle valve control means is set so as to switch the throttle valve to a fully closed state when the throttle valve is started . 2. The direct injection engine according to claim 1, wherein the air-fuel mixture concentration limiting means comprises a redo determination means for determining whether or not the start is a redo start, and an injector control means for controlling the second injector. And a direct injection engine in which the injector control means is set so as to reduce the fuel injection amount of the second injector in the case of re-starting . A direct injection engine having a first injector that directly injects fuel into a combustion chamber and a second injector that injects fuel into an intake passage that supplies air to the combustion chamber. In addition, in a direct injection engine configured to supply the fuel and air injected into the intake passage from the second injector into the combustion chamber, the intake valve with respect to the combustion end timing in the combustion chamber at the time of start-up Timing adjusting means for relatively delaying the valve opening timing of the engine, the timing adjusting means is configured to be capable of switching the cranking rotational speed, temperature detecting means for detecting the engine temperature, and controlling the starter. The starter control means is configured such that the lower the engine temperature, the lower the cranking speed. Direct-injection engine according to claim.

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