JP2004278382A - Starting control system of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for inexpensively, highly reliably and efficiently reducing a rotational load when starting an internal combustion engine without complicating a mechanism without having influence on a combustion state and ignitability of the internal combustion engine. <P>SOLUTION: This internal combustion engine has a plurality of cylinders (a #1 cylinder to a #4 cylinder), and reduces a pump loss by putting an intake valve and a vent valve in a fully closed state before first time combustion of the respective cylinders on at least its partial cylinder (the #1 cylinder, and the #4 cylinder) when starting the internal combustion engine by a starter motor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a start control system for an internal combustion engine.
[0002]
[Prior art]
Generally, an internal combustion engine is provided with a valve operating cam for driving an intake valve and an exhaust valve which are engine valves. Many of the valve cams are provided with a so-called decompression device that reduces the compression pressure of the combustion chamber of the internal combustion engine at the time of starting in order to reduce the load on the starter motor and the like at the time of starting the internal combustion engine.
[0003]
Many of such decompression devices use a centrifugal force to protrude and retract members on the base circle of the valve operating cam to form a cam lift portion, thereby opening the engine valve slightly in the compression stroke to release pressure. A variety of mechanisms have been proposed (for example, see Patent Documents 1 and 2).
[0004]
However, in the above-described prior art, the decompression operation may affect the combustion state of the internal combustion engine because the compression ratio is reduced in the compression stroke of the burning cylinder. In particular, in the case of a diesel engine, the ignition ratio may be deteriorated due to a decrease in the compression ratio.
[0005]
Further, in the above-described prior art, when the internal combustion engine has a plurality of cylinders, when the engine is started from 0 rotation at which the generated torque of the starter motor is most necessary, the rotational load in the non-combustible cylinder is not reduced. In addition, the rotational load of the entire internal combustion engine cannot be reduced efficiently.
[0006]
Further, in the above-described prior art, since a special decompression mechanism needs to be provided to the valve operating cam, the mechanism becomes complicated, which may lead to an increase in cost and a decrease in reliability.
[0007]
[Patent Document 1]
JP-A-11-229839
[Patent Document 2]
JP 09-184410 A
[0008]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the related art, and an object of the present invention is to provide a low-cost, complicated mechanism without affecting the combustion state and ignitability of an internal combustion engine. It is another object of the present invention to provide a technique capable of efficiently reducing the rotational load at the time of starting with high reliability.
[0009]
[Means for Solving the Problems]
The present invention for achieving the above object, in an internal combustion engine having a plurality of cylinders, when the internal combustion engine is started by the initial driving force applying means, at least some of the cylinders, before the first combustion of each cylinder Is to reduce pump loss for each cylinder.
[0010]
Further, in the present invention, there is provided a start control system for an internal combustion engine having a plurality of cylinders, the initial drive force applying means for applying an initial drive force to the internal combustion engine at the time of starting the internal combustion engine; Pump loss reducing means for reducing a pump loss for each cylinder before the first combustion of each cylinder for at least some of the cylinders.
[0011]
That is, in an internal combustion engine having a plurality of cylinders, after being started by the initial driving force applying means, fuel is burned in each cylinder in a predetermined order, so that the first combustion timing differs for each cylinder. . Therefore, when the internal combustion engine is started by the initial driving force applying means, at least some of the cylinders are reduced in pump loss for each cylinder before burning for the first time after starting.
[0012]
As described above, only before the first combustion in each cylinder, the pump loss is reduced for each cylinder, so that the reduction of the pump loss does not affect the combustion in each cylinder, and the internal combustion engine as a whole is efficiently started during startup. It is possible to reduce the rotational load.
[0013]
Therefore, even when the internal combustion engine is a diesel engine, a problem such as deterioration of ignitability due to a decrease in the compression ratio of the combustion cylinder does not occur.
[0014]
And, since the starting rotational load is reduced, when the initial driving force applying means is an electric starter motor, the size and battery capacity of the starter motor can be reduced, resulting in cost reduction and The weight of the entire internal combustion engine can be reduced.
[0015]
Further, in the present invention, the pump loss reducing means sets the intake valves and the exhaust valves of the at least some of the cylinders to a fully closed state or a fully opened state.
[0016]
That is, at the time of starting the internal combustion engine, before the first combustion in at least some of the cylinders, the pump loss is reduced by fully closing the intake valve and the exhaust valve.
[0017]
The present invention is based on the principle that, by fully closing the intake valve and the exhaust valve, only the elasticity of the air in the closed cylinder remains, and the pump loss accompanying the intake and exhaust of the air can be reduced to substantially zero. .
[0018]
This makes it possible to efficiently reduce the rotational load of the entire internal combustion engine at the time of starting with simple control.
[0019]
Further, when the internal combustion engine supports a reduced-cylinder operation in which fuel supply to some of the cylinders is interrupted and stopped according to operating conditions, a mechanism and control for performing the reduced-cylinder operation are performed. The above effects can be obtained with a simple configuration at low cost without using any special mechanism or control device as it can be used as it is.
[0020]
Further, in the present invention, the pump loss reduction by the pump loss reduction means is performed after the start of the application of the driving force by the initial driving force applying means until the intake stroke relating to the first combustion is started in each cylinder. It is characterized by.
[0021]
That is, by reducing the pump loss of each cylinder only during the period in which each cylinder starts the intake stroke related to the first combustion, it is more certain that the problem that reducing the pump loss of each cylinder affects combustion is reduced. Can be prevented.
[0022]
Further, in the present invention, each of the cylinders has a first cylinder group which is a target of a combustion start control at the start of the engine and a second cylinder group which is not a target of a combustion start control at the start of the engine. The means reduces pump loss for the cylinders belonging to the second cylinder group.
[0023]
That is, among a plurality of cylinders of the internal combustion engine, a cylinder whose combustion start is controlled at the start of the engine may enter the intake stroke immediately in preparation for combustion at the start of the engine. , And the pump loss is reduced only for the cylinders whose combustion start control is not performed at the beginning of the start.
[0024]
As a result, it is possible to achieve both a rapid start of combustion in the internal combustion engine and a decrease in the starting rotational load of the entire internal combustion engine.
[0025]
Further, according to the present invention, there is provided a start control system for an internal combustion engine having a plurality of cylinders, the initial drive force applying means for applying an initial drive force to the internal combustion engine at the time of starting the internal combustion engine; A valve operating cylinder group in which the opening and closing operations of the intake valve and the exhaust valve are performed from the start of the application of the initial driving force by the means, and the intake and exhaust valves are fully closed from the start of the application of the initial driving force by the initial driving force applying means. At a predetermined time after the start of the application of the driving force by the driving force applying unit, each cylinder of the valve operating cylinder group is moved to a compression top dead center. Initial combustion cylinder determining means for determining an initial combustion cylinder whose combustion start control is the earliest among the plurality of cylinders at the beginning of startup based on the timing of reaching, and the initial combustion cylinder determined by the initial combustion cylinder determining means. Combustion order control means for performing combustion start control for each of the plurality of cylinders according to a predetermined order; and after the initial combustion cylinder is determined by the initial combustion cylinder determination means, combustion is performed in a predetermined order by the combustion order control means. An intake / exhaust valve for starting the opening / closing operation of the intake valve and the exhaust valve of each cylinder of the valve-deactivated cylinder group for each of the cylinders during a period before the first combustion of each cylinder of the valve-deactivated cylinder group to be controlled to start. Starting means.
[0026]
That is, a plurality of cylinders of the internal combustion engine, a group of valve operating cylinders in which the opening and closing operations of the intake valve and the exhaust valve are performed from the start of the start by the initial driving force applying unit, Dividing into a valve-deactivated cylinder group in which the exhaust valve is fully closed and deciding the cylinder to be burned first from the valve-operating cylinder group, the earliest start of combustion among the plurality of cylinders of the internal combustion engine in the early stage of starting The cylinders to be controlled are prepared for the start of combustion from the start of the start. For the cylinders of which the start of combustion is not controlled earliest among the plurality of cylinders, the intake and exhaust valves are fully closed at the start of the start. By doing so, the pump loss can be reduced.
[0027]
Here, from the valve operating cylinder group in which the opening and closing operations of the intake valve and the exhaust valve are performed from the start of the start by the initial driving force applying means, based on the timing when each of the cylinders thereafter reaches the compression top dead center, By determining the cylinder whose combustion start control is performed early, the combustion is started from the cylinder closest to the compression top dead center regardless of the state of the piston of each cylinder of the valve operating cylinder group in any state. Therefore, there is little possibility that the initial driving force applying means needs to be driven for a long time, and the burden on the initial driving force applying means can be reduced.
[0028]
In addition, by providing a valve-stop cylinder group that completely closes the intake valve and the exhaust valve at the time of starting separately from those cylinders, the pump loss is reduced for a desired number of cylinders that are not likely to burn first. Thus, the rotational load of the entire internal combustion engine can be efficiently reduced.
[0029]
Further, the combustion operation control means determines the combustion order of all cylinders at the time when the first cylinder to be subjected to combustion control is determined first by the initial combustion cylinder determination means. The opening and closing of the intake valve and the exhaust valve are started before the first combustion of each cylinder, and preparation for combustion of each cylinder is started.
[0030]
Thus, for each cylinder of the valve deactivated cylinder group, it is possible to maintain the pump loss reduced state for the longest time within a range that does not affect the combustion of the entire internal combustion engine. Can be efficiently reduced.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
[0032]
(First Embodiment)
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine 1 to which the present invention is applied. FIG. 2 is a cross-sectional view showing a schematic configuration inside cylinder 21 of internal combustion engine 1 according to the present embodiment. In FIG. 1, an internal combustion engine 1 is a four-cylinder water-cooled diesel engine.
[0033]
The internal combustion engine 1 is provided with a starter motor 20 as an initial driving force applying means. When the internal combustion engine 1 is started, the rotation driving force of the starter motor 20 is transmitted by a timing belt (not shown) to the crankshaft 56 of the internal combustion engine 1. It starts by telling.
[0034]
An intake branch pipe 2 is connected to the internal combustion engine 1, and each branch pipe of the intake branch pipe 2 communicates with a combustion chamber 30 of each cylinder 21 via an intake port 28. In the intake system configured as described above, fresh air that has flowed into the air cleaner box 4 is guided to the intake branch pipe 2 via the intake pipe 3 after dust and dust are removed by the air filter, and The fuel is distributed to the combustion chamber 30 of each cylinder 21 through each branch pipe.
[0035]
On the other hand, an exhaust branch pipe 6 is connected to the internal combustion engine 1, and each branch pipe of the exhaust branch pipe 6 communicates with a combustion chamber 30 of each cylinder 21 via an exhaust port 29. The exhaust branch pipe 6 is connected to an exhaust pipe 7, and an exhaust purification catalyst 8 is provided in the exhaust pipe 7. In the exhaust system configured as described above, the air-fuel mixture burned in the combustion chamber 30 of each cylinder 21 is guided to the exhaust pipe 7 through each branch pipe of the exhaust branch pipe 6 and flows into the exhaust purification catalyst 8.
[0036]
Next, one fuel injection valve 10 is attached to the internal combustion engine 1 for each cylinder. Each fuel injection valve 10 is mounted so that its injection hole faces the combustion chamber 30 of each cylinder 21, and can directly inject fuel into the combustion chamber 30. The fuel injection valve 10 communicates with a pressure accumulation chamber (common rail) 12 via a fuel distribution pipe 11, and the common rail 12 communicates with a fuel pump (not shown) via a fuel passage 13.
[0037]
In the fuel injection system configured as described above, the fuel discharged from the fuel pump is accumulated in the common rail 12 to a predetermined pressure, and the accumulated fuel is applied to the fuel injection valve 10 through the fuel distribution pipe 11. Then, when the fuel injection valve 10 is opened, the accumulated fuel is injected into the combustion chamber 30.
[0038]
The internal combustion engine 1 is also provided with an electronic control unit (ECU: Electronic Control Unit) 22 for engine control. The ECU 22 includes a CPU, a ROM, a RAM, an input interface circuit, an output interface circuit, and the like, which are interconnected by a bidirectional bus. Various sensors are connected to the input interface circuit via electric wiring. I have.
[0039]
In addition, the intake valve 61 and the exhaust valve 62 of the internal combustion engine 1 according to the present embodiment have a so-called half camless structure.
[0040]
In FIG. 2, an intake valve 61 and an exhaust valve 62 are provided in a cylinder 21 having a half camless structure, respectively. With respect to the intake valve 61, the cam 15 rotates and comes into sliding contact with the cam contact portion 16, and the cam contact portion 16 is moved up and down to perform the opening / closing valve operation.
[0041]
At the time of the above-described full closing operation of the intake valve 61, the intake valve 61 is stopped in a raised state by controlling the oil pressure to a valve stop mechanism (not shown) according to a command from the ECU 22.
[0042]
On the other hand, an electromagnetic drive unit 63 that moves the exhaust valve 62 up and down by electromagnetic force is connected to the exhaust valve 62. When such an electromagnetic drive unit 63 is used, the exhaust valve 62 can be opened and closed at an arbitrary timing by a command from the ECU 22, and can be opened by an arbitrary lift amount. .
[0043]
Therefore, when the exhaust valve 62 is fully closed, the drive signal of the electromagnetic drive unit 63 is controlled by a command from the ECU 22 to raise and close the exhaust valve 62. Since the control method of the intake valve 61 and the exhaust valve 62 is a known technique, a detailed description thereof will be omitted. Here, the pump loss reducing means in the present embodiment includes the ECU 22, the electromagnetic drive unit 63, a valve stop mechanism (not shown), and the like.
[0044]
In the present embodiment, as shown in FIG. 2, an example is shown in which the intake valve 61 is controlled to open and close by the cam 15, and the exhaust valve 62 is controlled to be opened and closed by the electromagnetic drive unit 63. Both the exhaust valve 62 may be controlled by the rotation of the two cams 15, and both the intake valve 61 and the exhaust valve 62 may be controlled by the two electromagnetic drive units 63.
[0045]
Next, the cylinder discrimination in the present embodiment will be described. A crank test rotor 51 having a plurality of test teeth formed along its outer periphery is mounted on the crankshaft 56. A crank for detecting passage of the test teeth is provided near the crank test rotor 51. A position sensor 52 is provided. The crank position sensor 52 is a magnet pickup (MPU) type sensor, and outputs a crank angle signal as the subject teeth pass.
[0046]
In the present embodiment, the teeth to be inspected are formed at 10 ° crank angle (CA) intervals, and a crank angle signal is output each time the crankshaft 56 rotates 10 ° CA. The position of the piston 31 can be detected from the crank angle signal.
[0047]
On the other hand, the cam 15 is provided with a cam test rotor 53 having a test piece 54 formed at one place on the outer periphery thereof, and detects the passage of the test piece 54 near the cam test rotor 53. A cam position sensor 55 is provided. The cam position sensor 55 is an MPU-type sensor, and outputs a cylinder discrimination signal as the test piece 54 passes.
[0048]
The cylinder discrimination signal is a signal indicating a time when a specific cylinder, for example, the # 1 cylinder 21a is located 90 ° before the compression top dead center, and is output every 720 ° CA in the present embodiment. The cam position sensor 55 is connected to the ECU 22 by electric wiring, and the ECU 22 determines the time when the specific cylinder reaches 90 ° before the compression top dead center based on the output cylinder determination signal.
[0049]
Next, the start control according to the present embodiment will be described with reference to FIGS. FIG. 3 is a flowchart illustrating a start control routine according to the present embodiment. This routine is executed when a request to start the internal combustion engine 1 is made by the driver's intention, such as when starting the internal combustion engine 1 by a key.
[0050]
In the start control routine shown in FIG. 3, first, in S301, the ECU 22 closes the intake valves 61 and the exhaust valves 62 of the cylinder group that are not subjected to the combustion start control at the beginning of the start, so as to be in a so-called fully closed state. Next, the process proceeds to S302, in which the opening and closing operation of the intake valve 61 and the exhaust valve 62 of the cylinder group to be subjected to the combustion start control at the beginning of the start is started.
[0051]
Here, in the present embodiment, the four cylinders 21 of the internal combustion engine 1 are divided in advance into a group of cylinders to be subjected to combustion start control at the beginning of the start and a group of cylinders not to be subjected to combustion start at the start of the start. . Specifically, among the four cylinders 21 of the internal combustion engine 1, the # 2 cylinder 21b and the # 3 cylinder 21c are set as the combustion start control targets at the start of the start, and the # 1 cylinder 21a and # 4 cylinder 21d start the combustion start at the start of the start. Not controlled. Therefore, in S301, the intake valves 61 and the exhaust valves 62 of the # 1 cylinder 21a and the # 4 cylinder 21d are fully closed, and in S302, the opening and closing of the intake valves 61 and the exhaust valves 62 only for the # 2 cylinder 21b and the # 3 cylinder 21c. Start operation.
[0052]
Next, in S303, the starter motor 20 as the initial driving force applying means is rotated. Here, the crankshaft 56 is rotated by the driving force of the starter motor 20 until the internal combustion engine 1 continues to rotate stably after the cylinder 21 whose combustion start control is first started. Next, cylinder determination is performed in S304. The cylinder discrimination is a process of discriminating which cylinder 21 of the internal combustion engine 1 is 90 ° before the compression top dead center as described above.
[0053]
Next, proceeding to S305, if it is the # 1 cylinder 21a that is 90 ° before the compression top dead center in the previous process, the process proceeds to S306, and the combustion start control is started for the # 3 cylinder 21c. The reason why the combustion start control is started only for the # 3 cylinder 21c will be described later.
[0054]
This combustion start control is performed by a program stored in a ROM in the ECU 22, a fuel injection amount and detailed fuel injection timing of each cylinder 21 are determined, and a predetermined amount of fuel is supplied at a predetermined time near the compression top dead center. It is injected. Since this control is known, a detailed description thereof will be omitted. In this embodiment, the order of cylinder combustion is set as # 3, # 4, # 2, # 1.
[0055]
Next, the process proceeds to S307, in which the combustion start control is performed on the # 4 cylinder 21d burning after the # 3 cylinder 21c in the same manner as in S306. Then, in S308, the opening / closing operation of the intake valve 61 and the exhaust valve 62 of the # 4 cylinder 21d is started from the immediately following intake stroke. That is, for the # 4 cylinder 21d, the fully closed state of the intake valve 61 and the exhaust valve 62 has been released from this intake stroke.
[0056]
Then, the process proceeds to S309, in which combustion start control is performed for the # 2 cylinder 21b that will burn next. Thereafter, in S310, the combustion start control is also performed on the # 1 cylinder 21a. Then, in S311, the opening / closing operation of the intake valve 61 and the exhaust valve 62 of the # 1 cylinder 21a is started immediately after the intake stroke. The fully closed state of the intake valve 61 and the exhaust valve 62 of the cylinder 21a is released.
[0057]
Here, the combustion start control of the four cylinders 21 and the opening / closing operation of the intake valve 61 and the exhaust valve 62 are started, and the internal combustion engine 1 is operated stably. Finally, the starter motor 20 is stopped in S312. To exit this routine. On the other hand, in S304, when it is determined that the determined cylinder is the # 4 cylinder 21d, the process proceeds to S313, and the combustion start control is performed on the # 2 cylinder 21b.
[0058]
Next, the process proceeds to S314, in which the combustion start control is performed on the # 1 cylinder 21a that burns after the # 2 cylinder 21b in the same manner as that performed in S313. Then, in S315, the opening / closing operation of the intake valve 61 and the exhaust valve 62 of the # 1 cylinder 21a is started from the immediately following intake stroke, and the fully closed state is released. Then, the process proceeds to S316, in which combustion start control is performed for the # 3 cylinder 21c to be burned next.
[0059]
Thereafter, in S317, the combustion start control is also performed on the # 4 cylinder 21d. Then, in S318, the opening / closing operation of the intake valve 61 and the exhaust valve 62 of the # 4 cylinder 21d is started immediately after the intake stroke, and the cylinder is fully closed. The state is released. Finally, in step S312, the starter motor 20 is stopped, and the routine exits.
[0060]
Note that the initial combustion cylinder determining means in the present embodiment includes the crank position sensor 52, the cam position sensor 55, the ECU 22, and the like necessary for the above-described cylinder discrimination. The combustion order control means is configured to include the ECU 22 having a ROM storing a program for burning each cylinder in the above-described order and a program for controlling combustion start. Further, the intake / exhaust valve starting means in the present embodiment is configured to include the ECU 22 having a ROM storing this routine.
[0061]
Next, the operation of the start control routine will be described in detail with reference to FIG. FIG. 4 is a time chart showing the stroke immediately after the start of the start for the # 1 cylinder 21a to the # 4 cylinder 21d provided in the internal combustion engine 1. Each of these cylinders executes four strokes of intake, compression, expansion, and exhaust at different phases.
[0062]
In the present embodiment, as described above, it is set so that the combustion start control is performed in either the # 2 cylinder 21b or the # 3 cylinder 21c at the beginning of the start. Therefore, the # 2 cylinder 21b and the # 3 cylinder 21c start opening and closing the intake valve 61 and the exhaust valve 62 from the start.
[0063]
This is because, for the two cylinders 21 described above, unless the opening and closing of the intake valve 61 and the exhaust valve 62 is started from the time of starting, it is impossible to catch up with the first combustion operation. As a specific operation, in response to a command from the ECU 22, the intake valve 61 is controlled by a hydraulic pressure to a valve stop mechanism (not shown) so that the intake valve 61 can be moved up and down. The up / down movement of the exhaust valve 62 is started by controlling the supply of current to the exhaust valve 62.
[0064]
At this time, the intake valves 61 and the exhaust valves 62 of the # 1 cylinder 21a and the # 4 cylinder 21d are fully closed.
[0065]
Next, the starter motor 20 as the initial driving force applying means starts rotating, and the rotation of the starter motor 20 is transmitted to the crankshaft 56 by a timing belt (not shown), whereby the crankshaft 56 starts rotating. Accordingly, the piston 31 of each cylinder 21 also starts to move up and down.
[0066]
Next, cylinder discrimination is performed at a time corresponding to the one-dot chain line shown in FIG. 4, and this cylinder discrimination is performed at a timing 90 ° before the # 1 cylinder 21a or # 4 cylinder 21d reaches the compression top dead center as described above. It is set to be performed in.
[0067]
This timing is detected by the ECU 22 detecting a predetermined crank angle signal from the crank position sensor 52. If the cylinder discrimination signal is output from the cam position sensor 55 at that time, the # 1 cylinder 21a is compressed. If the cylinder is at a position 90 ° before top dead center and no cylinder discrimination signal is output from the cam position sensor 55, it is determined that the # 4 cylinder 21d is 90 ° before compression top dead center.
[0068]
FIG. 4 illustrates a case where the # 1 cylinder 21a is determined to be 90 ° before the compression top dead center in the cylinder determination. After the cylinder discrimination is performed, the combustion start control is first performed for the # 3 cylinder 21c as described above.
[0069]
This is because when the cylinder discrimination result is # 1 cylinder 21a, the # 3 cylinder 21c reaches the compression top dead center earlier than the # 2 cylinder 21b, so that the # 3 cylinder 21c burns first. By performing the start control, the combustion as the internal combustion engine 1 is started at the earliest time, and the load on the starter motor 20 is reduced.
[0070]
After that, since the # 4 cylinder 21d burns before the # 1 cylinder 21a, the combustion start control is performed for the # 4 cylinder 21d, and the opening and closing of the intake valve 61 and the exhaust valve 62 are performed from the intake stroke immediately after that. Start. As a result, the fully closed state of the intake valve 61 and the exhaust valve 62 for the # 4 cylinder 21d is released. Here, the reason why the combustion is not performed at the compression top dead center of the # 1 cylinder 21a immediately after the cylinder discrimination timing is that the preparation for combustion cannot be made in time.
[0071]
Then, after the combustion start control is performed on the # 2 cylinder 21b that burns next to the # 4 cylinder 21d, the combustion start control is performed on the # 1 cylinder 21a that should start combustion last. Immediately thereafter, when the # 1 cylinder 21a reaches the intake stroke, the # 4 cylinder 21d burns almost simultaneously. At this time, the opening and closing of the intake valve 61 and the exhaust valve 62 of the # 1 cylinder 21a are started, and the fully closed state of the intake valve 61 and the exhaust valve 62 of the # 1 cylinder 21a is released. Thereafter, the internal combustion engine 1 repeats combustion in the order described above.
[0072]
According to the present embodiment, for the # 1 cylinder 21a and the # 4 cylinder 21d that are set so that the combustion start control is not performed at the beginning of the start, when the starter motor 20 starts the internal combustion engine 1, the intake valves 61 and The exhaust valve 62 is in the fully closed state, and the exhaust valve 62 is kept in the fully closed state until the intake stroke related to the first combustion of the cylinders 21 after the cylinder discrimination, so that the air is exhausted from the intake port 28 and the exhaust port 29. No accompanying pump loss occurs, and the pump loss of the internal combustion engine 1 as a whole is reduced.
[0073]
As a result, the size of the starter motor 20 can be reduced, the capacity of the battery for driving the starter motor 20 can be reduced, and the cost and weight can be reduced.
[0074]
Further, regarding the # 2 cylinder 21b and the # 3 cylinder 21c which are set so that the combustion start control is performed at the beginning of the start, the intake valve 61 and the exhaust valve 62 open and close from the start of the internal combustion engine 1 because the intake valve 61 and the exhaust valve 62 operate. During the initial combustion, the pressure inside the cylinder is the same as in normal operation, and the reduction in pump loss affects the combustion state in the burning cylinder as in the case where the compression ratio of the cylinder burning by the decompression mechanism is reduced. There is no. In particular, in a diesel engine, there is no problem such as deterioration of ignitability due to a decrease in compression ratio.
[0075]
Further, in the present embodiment, in the case where the internal combustion engine 1 corresponds to the reduced cylinder operation in which the fuel supply to some of the cylinders is interrupted and stopped according to the operating conditions in order to improve the fuel efficiency, conventionally. Can use the mechanism and control for performing the reduced-cylinder operation as they are, without the need for a special mechanism or control device, can achieve the above effects with a low-cost and simple configuration.
[0076]
In this embodiment, the case where the internal combustion engine 1 is started by the driver's key operation has been described, but the present invention can also be applied to the case where the internal combustion engine 1 is automatically stopped by so-called eco-run control and then restarted. . In particular, in this case, when the internal combustion engine 1 is started, there is no possibility that only low-temperature air is discharged from the unburned cylinders 21, and a problem such as lowering the catalyst bed temperature of the exhaust purification catalyst 8 does not occur.
[0077]
In this embodiment, the present invention is applied to a four-cylinder diesel engine. However, the present invention can be applied to an engine having another number of cylinders such as a six-cylinder engine. Of course. Furthermore, the present invention is also applicable to a hybrid vehicle that can be driven by an engine and an electric motor. In this case, a motor generator that functions as a motor and a generator in the hybrid vehicle may be used as the initial driving force applying unit. Good.
[0078]
(Second embodiment)
Next, a second embodiment will be described. Here, a configuration different from the above-described first embodiment will be described, and a description of the same configuration will be omitted. Other configurations and operations are the same as those of the first embodiment, and therefore, the same components will be denoted by the same reference characters and description thereof will be omitted.
[0079]
In the present embodiment, an example will be described in which the pump loss in the cylinder 21 not set to burn first is reduced by another method.
[0080]
In the present embodiment, in S301 of the start control routine in FIG. 3, the intake valve 61 and the exhaust valve 62 of the cylinder 21 that is not set to perform the combustion start control at the beginning of the start are fully opened. As a specific operation, the hydraulic pressure to the valve stop mechanism (not shown) is controlled for the intake valve 61 in accordance with a command from the ECU 22, and the intake valve 61 is fixed in a state of being lowered to the maximum. With respect to the exhaust valve 62, energization to the electromagnetic drive unit 63 is controlled, and the exhaust valve 62 is lowered to the maximum. Other controls are performed in the same manner as in the first embodiment.
[0081]
According to the present embodiment, although air is sucked and exhausted in a cylinder in which fuel injection and combustion are not performed, the air passage area in the intake port 28 and the exhaust port 29 is maximized. The pump loss can be greatly reduced as compared with the case of operating.
[0082]
As a result, as in the first embodiment, the size of the starter motor 20 can be reduced, the battery capacity for driving the starter motor 20 can be reduced, and the cost and weight can be reduced.
[0083]
Further, for the # 2 cylinder 21b and the # 3 cylinder 21c set so that the combustion start control is performed at the beginning of the start, the reduction of the pump loss does not affect the combustion state of the burning cylinder. As in the first embodiment, there is no problem such as deterioration of ignitability due to a decrease in compression ratio.
[0084]
Further, when the internal combustion engine 1 is compatible with the reduced cylinder operation, the mechanism and control for performing the reduced cylinder operation can be used as they are, similarly to the first embodiment, and the cost and the cost are reduced. With such a configuration, the above effect can be obtained.
[0085]
The present embodiment can also be applied to a case where the internal combustion engine 1 is automatically stopped and restarted by so-called eco-run control. Further, the present invention can be applied to an engine having another number of cylinders, such as a six-cylinder engine, and a gasoline engine.
[0086]
Furthermore, the present invention is also applicable to a hybrid vehicle that can be driven by an engine and an electric motor. In this case, a motor generator that functions as a motor and a generator in the hybrid vehicle may be used as the initial driving force applying unit. Good.
[0087]
【The invention's effect】
As described above, according to the present invention, in an internal combustion engine having a plurality of cylinders, when the internal combustion engine is started by the initial driving force applying means, at least a part of the cylinders is activated before the first combustion of each cylinder. Reduces the pump loss for each cylinder, so that the reduction of the pump loss does not affect the combustion of each cylinder, and it is possible to efficiently reduce the starting rotational load of the entire internal combustion engine.
[0088]
Therefore, even when the internal combustion engine is a diesel engine, a problem such as deterioration of ignitability due to a decrease in the compression ratio of the combustion cylinder does not occur.
[0089]
When the initial driving force applying means is an electric starter motor, the starter motor can be downsized and the battery capacity can be reduced because the starting rotational load is reduced. As a result, cost and internal combustion can be reduced. The weight of the entire engine can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which the present invention is applied.
FIG. 2 is a sectional view showing a schematic configuration inside a cylinder of the internal combustion engine according to the first embodiment of the present invention.
FIG. 3 is a flowchart illustrating a start control routine according to the first embodiment of the present invention.
FIG. 4 is a time chart showing a stroke immediately after start of starting for four cylinders provided in the internal combustion engine according to the first embodiment of the present invention.
[Explanation of symbols]
1. Internal combustion engine
10. Fuel injection valve
15 ... Cam
20 Starter motor (initial driving force applying means)
21 ... cylinder
22 ... ECU
28 ... intake port
29… Exhaust port
51 ... Crank test rotor
52 ... Crank position sensor
53 ... Cam inspection rotor
54 ... Test piece
55 ... Cam position sensor
56 ... Crankshaft
61 ... intake valve
62 ... exhaust valve

Claims (5)

A start control system for an internal combustion engine having a plurality of cylinders,
Initial driving force applying means for applying an initial driving force to the internal combustion engine at the time of starting the internal combustion engine,
At the time of the start, for at least some of the plurality of cylinders, a pump loss reducing means for reducing a pump loss for each cylinder before the first combustion of each cylinder,
A start control system for an internal combustion engine, comprising: The pump loss reducing means,
The start control system for an internal combustion engine according to claim 1, wherein the intake valves and the exhaust valves of the at least some of the cylinders are set to a fully closed state or a fully opened state. 2. The method according to claim 1, wherein the step of reducing the pump loss by the pump loss reducing unit is performed from the start of the application of the driving force by the initial driving force applying unit to the start of the intake stroke related to the first combustion in each cylinder. Or a start control system for an internal combustion engine according to item 2. Each of the cylinders includes a first group of cylinders that are not subject to combustion start control at the beginning of the start and a second group of cylinders that are not subject to combustion start control at the beginning of the start. 4. The start control system for an internal combustion engine according to claim 1, wherein the pump loss is reduced for the cylinders belonging to the cylinder group. A start control system for an internal combustion engine having a plurality of cylinders,
Initial driving force applying means for applying an initial driving force to the internal combustion engine at the time of starting the internal combustion engine,
A valve operating cylinder group in which the opening and closing operations of the intake valve and the exhaust valve are performed from the start of applying the initial driving force by the initial driving force applying unit,
A valve rest cylinder group in which the intake valve and the exhaust valve are fully closed from the start of the application of the initial driving force by the initial driving force applying means,
At a predetermined time after the start of the application of the driving force by the driving force applying means, from the valve operating cylinder group, based on the timing at which each cylinder of the valve operating cylinder group subsequently reaches the compression top dead center, the engine is initially started. Initial combustion cylinder determining means for determining an initial combustion cylinder for which combustion start control is performed earliest among the plurality of cylinders,
From the initial combustion cylinder determined by the initial combustion cylinder determination means, combustion order control means for performing combustion start control for each of the plurality of cylinders according to a predetermined order,
A period after the initial combustion cylinder is determined by the initial combustion cylinder determining means and before the first combustion of each cylinder of the valve-disabled cylinder group whose combustion start is controlled according to a predetermined order by the combustion order control means. Intake / exhaust valve starting means for starting opening / closing operation of an intake valve and an exhaust valve of each cylinder of the valve deactivated cylinder group for each of the cylinders,
A start control system for an internal combustion engine, comprising:

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