JP2009024685A - Control device for internal combustion engine - Google Patents

Abstract

A control device for an internal combustion engine capable of appropriately preventing the deterioration of a combustion state caused by condensed water and suppressing an unstable operation state of the internal combustion engine.
SOLUTION: A plurality of cylinders 2, an intake manifold 5 for guiding intake air to each of the plurality of cylinders 2, a part of exhaust gas is taken out as EGR gas from an exhaust passage 4, and is returned to an intake passage 3 upstream of the intake manifold 5. In the control device applied to the internal combustion engine 1 including the EGR device 14, the intake manifold 5 is directed to the intake manifold 5 so that the intake air flowing into the intake manifold 5 flows toward the # 2 cylinder 2. A wraparound prevention wall 5a is provided to control the fuel injection timing of the # 1 cylinder 2 so that the difference between the torque generated in the # 1 cylinder 2 and the torque generated in the # 2 to # 4 cylinder 2 is reduced. To do.
[Selection] Figure 2

Description

  The present invention relates to a control device for an internal combustion engine including an EGR device that recirculates part of exhaust gas from an exhaust passage to an intake passage.

  An exhaust gas recirculation passage on the downstream side of the cooling device in order to suppress inflow of the condensed water generated by the cooling device, which is interposed in the exhaust gas recirculation passage, into the engine through the intake passage of the cooling device; A drain passage communicating with the exhaust passage on the downstream side of the turbine of the turbocharger is provided, and a gas-liquid separator is provided at the connection between the exhaust gas recirculation passage and the drain passage. When the engine is idling, the drain passage is opened and closed. There is known an exhaust gas recirculation device that opens an on-off valve that closes the on-off valve when the engine is not idling (see Patent Document 1). In addition, Patent Documents 2 and 3 exist as prior art documents related to the present invention.

JP 2006-274961 A Japanese Patent No. 3666583 JP 2003-097361 A

  There are various devices that separate liquids from gas, such as the gas-liquid separator provided in the device of Patent Document 1, but the EGR gas and condensed water that moves with intake air are completely separated from those gases. It is difficult to do. Therefore, a part of the generated condensed water flows into the cylinder of the internal combustion engine. If the condensed water flows into the cylinder, the combustion state of the cylinder is deteriorated by the condensed water, so that the operation state of the internal combustion engine may become unstable.

  Accordingly, an object of the present invention is to provide a control device for an internal combustion engine that can appropriately prevent the combustion state of the internal combustion engine from becoming unstable in response to the deterioration of the combustion state caused by condensed water. And

  The control apparatus for an internal combustion engine according to the present invention includes a plurality of cylinders, an intake manifold that guides intake air to each of the plurality of cylinders, and an intake passage upstream of the intake manifold by taking out part of the exhaust as EGR gas from the exhaust passage. In the control device applied to the internal combustion engine provided with the EGR device that recirculates the air, the intake air that is provided in the intake manifold and flows into the intake manifold flows toward some of the plurality of cylinders In the combustion state of the internal combustion engine of the some cylinders so that the difference between the guidance means for directing the intake air and the torque generated in the some cylinders and the torque generated in the remaining cylinders becomes small Combustion control means for controlling the value of the influential combustion control parameter solves the above-mentioned problem (claims) ).

  According to the control device of the present invention, by introducing the intake air to some cylinders by the guiding means, the condensed water contained in the intake air is caused to flow into some cylinders using the inertia, and is supplied to the remaining cylinders. Inflow of condensed water can be suppressed. The combustion control means controls the combustion control parameters of some of the cylinders so that the difference between the torque generated in some of the cylinders and the torque generated in the remaining cylinders becomes small. Can be prevented from becoming unstable. In this way, when condensate water is guided to some cylinders and the inflow of condensate water to the remaining cylinders is suppressed, only the combustion state of some of the cylinders deteriorates. The cylinder can be specified in advance. Therefore, it is possible to simplify the countermeasures against the deterioration of the combustion state caused by the condensed water, and to appropriately cope with the deterioration of the combustion state. In addition, the intake air in the present invention means a gas flowing through the intake passage, and includes a mixture of so-called fresh air and EGR gas sucked from the outside.

  In one form of the control device of the present invention, the guide means may be provided in the intake manifold so that condensed water that has flowed into the intake manifold together with intake air is guided to the partial cylinders. ). By providing the guiding means in this way, the condensed water can be more reliably allowed to flow into some cylinders.

  In one form of the control device of the present invention, a cylinder located on an extension of a center line of an intake pipe connected to the intake manifold may be set in the some cylinders (Claim 3). . Since the condensed water is heavier than the gas, it moves in the direction of the intake air flow when it flows into the intake manifold. Therefore, by setting the cylinders at such positions to some cylinders, condensed water can be guided to some cylinders using inertia.

  In one form of the control device of the present invention, the guiding means may be a wall portion provided according to the flow of intake air flowing into the intake manifold. In this case, the intake air can be easily guided to some cylinders by the wall without providing a complicated mechanism.

  In one form of the control device of the present invention, the internal combustion engine further includes a fuel injection valve that is provided in each of the plurality of cylinders and injects fuel into the cylinder, and the combustion control means operates the fuel injection valve. Injection timing at which fuel is injected from the fuel injection valve by controlling the fuel injection, pilot injection in which a smaller amount of fuel than the main fuel injection is injected from the fuel injection valve prior to main fuel injection from the fuel injection valve At least one of the amount of fuel injected in step S4 and the number of pilot injections may be controlled as the combustion control parameter. By changing the amount of fuel supplied to some cylinders and the amount of fuel in this way, the combustion state of some cylinders is improved, and the torque generated in some cylinders and the torque generated in the remaining cylinders are reduced. The difference can be reduced. In addition, the combustion state of some cylinders deteriorated by the inflow of condensed water can be improved by advancing the fuel injection timing. Further, since the ignitability can be improved by increasing the fuel amount of pilot injection or increasing the number of pilot injections, the combustion state can be improved by these.

  In one form of the control device of the present invention, the internal combustion engine further includes a glow plug provided in each of the plurality of cylinders and capable of preheating the inside of the cylinder, and the combustion control means controls the operation of the glow plug. Thus, the temperature in the part of the cylinders may be controlled as the combustion control parameter. As the condensed water flows in, the temperature in the cylinder decreases, and thus the combustion state of some cylinders can be improved by preheating the inside of the cylinder with the glow plug and controlling the temperature in the cylinder. Therefore, the difference between the torque generated in some cylinders and the torque generated in the remaining cylinders can be reduced.

  In one form of the control device of the present invention, the control device further comprises condensed water amount estimating means for estimating the amount of condensed water flowing into the some cylinders together with intake air, and the combustion control means is estimated by the condensed water amount estimating means. The value of the combustion control parameter may be controlled so that the torque generated in the some cylinders increases as the amount of condensed water increases. Thus, by estimating the amount of condensed water flowing into some cylinders and controlling the value of the combustion control parameter based on the estimated amount, this value can be controlled appropriately. Therefore, the difference between the torque generated in some cylinders and the torque generated in the remaining cylinders can be further reduced, and the operation state of the internal combustion engine can be further appropriately prevented from becoming unstable.

  In this embodiment, the condensed water amount estimation means is based on the amount of fuel supplied to the plurality of cylinders, the flow rate of EGR gas recirculated by the EGR device, and the temperature of the intake air flowing into the intake manifold. You may estimate the quantity of the condensed water which flows in into some cylinders with intake (Claim 8). The amount of moisture in the exhaust gas recirculated as the EGR gas can be estimated based on the amount of fuel used for combustion. Therefore, the amount of moisture in the intake air flowing into the intake manifold can be estimated based on the flow rate of EGR gas and the amount of moisture in EGR gas. In addition, the lower the temperature of the intake air, the easier the moisture in the intake air is condensed. Therefore, it is possible to estimate the amount of condensed water flowing into some of the cylinders together with the intake air based on these.

  In one form of the control device of the present invention, the control device further includes a combustion state detection unit that is provided in the some cylinders and detects a combustion state of the some cylinders, and the combustion control unit includes the combustion state detection unit. The value of the combustion control parameter may be controlled based on the detection result of (Claim 9). In this way, by detecting the combustion state of some cylinders and controlling the values of the combustion control parameters of some cylinders based on the detection results, these values can be controlled appropriately. Therefore, it is possible to appropriately prevent the operating state of the internal combustion engine from becoming unstable.

  In this embodiment, the combustion state detection means detects combustion pressure detection means for detecting the combustion pressure of the some cylinders, and detects ions generated in the combustion gas when fuel burns in the some cylinders. It may be at least one of ion detection means (claim 10). The change in the combustion state appears in the combustion pressure that is the pressure when the fuel burns in the cylinder and the amount of ions generated by the combustion. Therefore, it is only necessary to detect the combustion state of some cylinders by providing detection means for detecting these.

  As described above, according to the control device of the present invention, the flow of condensed water into the remaining cylinders can be suppressed by flowing the condensed water into some of the plurality of cylinders. Then, the difference between the torque generated in some cylinders and the torque generated in the remaining cylinders is controlled by controlling the values of the combustion control parameters of some cylinders into which the condensed water has flowed. It is possible to prevent the operating state of the internal combustion engine from becoming unstable in response to the deterioration of the combustion state.

  FIG. 1 is a diagram showing an outline of an internal combustion engine in which a control device according to one embodiment of the present invention is incorporated. An internal combustion engine (hereinafter also referred to as an engine) 1 in FIG. 1 is a diesel engine mounted on a vehicle as a driving power source, and includes a plurality (four in FIG. 1) of cylinders 2 and each cylinder 2. Are provided with an intake passage 3 and an exhaust passage 4, respectively. As shown in FIG. 1, the cylinders 2 are distinguished from each other by attaching cylinder numbers # 1 to # 4 from one end to the other end in the arrangement direction. A part of the intake passage 3 is formed by an intake manifold 5 that guides intake air to each cylinder 2, and a part of the exhaust passage 4 is formed by an exhaust manifold 6 that collects exhaust discharged from each cylinder 2. . In the intake passage 3, an air cleaner 7 for filtering the intake air, an air flow meter 8 for outputting a signal corresponding to the intake air amount, a compressor 9a of the turbocharger 9, an intercooler 10 for cooling the intake air, and an intake air amount A throttle valve 11 is provided for adjusting. The exhaust passage 4 is provided with a turbine 9b of the turbocharger 9 and exhaust purification devices 12 and 13 for purifying exhaust. As the exhaust gas purification devices 12 and 13, for example, a particulate filter, an oxidation catalyst, a three-way catalyst, and the like that collect particulate matter (PM) in the exhaust gas are provided.

  FIG. 2 shows the inside of the intake manifold 5 in an enlarged manner. In FIG. 2, the intake air is guided from the lower side of FIG. 2 to the intake manifold 5. As shown in FIG. 2, the # 1 cylinder 2 is located on the extension of the center line CL of the intake pipe 3 a connected to the intake manifold 5. Inside the intake manifold 5, there is provided a wraparound prevention wall 5a as a wall portion for directing the intake air so that the intake air flowing into the intake manifold 5 flows toward the # 1 cylinder 2. . Therefore, # 1 cylinder 2 corresponds to a part of the cylinders of the present invention, and # 2 to # 4 cylinders 2 correspond to the remaining cylinders of the present invention. Further, the wraparound prevention wall 5a corresponds to the guiding means of the present invention. As is well known, the intake air includes condensed water that is condensed into water droplets in the intake air. Since the condensed water is heavier than the gas component of the intake air, by providing the wraparound prevention wall 5a in this way, the condensed water flowing into the intake manifold 5 together with the intake air as shown by the arrow A in FIG. It can be led to the cylinder 2 of # 1. Therefore, it is possible to suppress the inflow of condensed water into the cylinders 2 of # 2 to # 4 and allow the condensed water to flow into the cylinder 2 of # 1.

  Returning to FIG. 1, the description of the engine 1 will be continued. The engine 1 includes an EGR device 14 that extracts a part of the exhaust gas from the exhaust passage 4 and returns it to the intake passage 3. The EGR device 14 includes a first EGR passage 20 and a second EGR passage 21 that connect the exhaust passage 4 and the intake passage 3. As shown in FIG. 1, the first EGR passage 20 connects the exhaust passage 4 downstream of the exhaust purification device 10 and the intake passage 3 upstream of the compressor 7a. On the other hand, the second EGR passage 21 communicates the exhaust passage 4 upstream from the turbine 7b and the intake passage 3 downstream from the compressor 7a. Therefore, the EGR gas is returned to the intake passage 3 upstream of the intake manifold 5. The first EGR passage 20 is led to the intake passage 4 via the first EGR cooler 22 for cooling the exhaust gas recirculated to the intake passage 4 (hereinafter also referred to as EGR gas) and the first EGR passage 20. A first EGR valve 23 is provided for adjusting the flow rate of the EGR gas to be discharged (hereinafter sometimes referred to as first EGR gas). The second EGR passage 21 has a second EGR cooler 24 for cooling the EGR gas, and a flow rate of EGR gas (hereinafter sometimes referred to as second EGR gas) guided to the intake passage 4 via the second EGR passage 21. The second EGR valve 25 as a high pressure EGR valve is provided for adjusting the pressure.

  Each cylinder 2 is provided with an injector 30 as a fuel injection valve for injecting fuel into the cylinder 2. Each injector 30 is connected to a common rail 31 in which high-pressure fuel supplied to the injector 30 is stored.

  The operation of each injector 30 is controlled by an engine control unit (ECU) 40, respectively. The ECU 40 is configured as a computer including a microprocessor and peripheral devices such as a RAM and a ROM necessary for its operation, and controls the operating state of the engine 1 based on output signals of various sensors provided in the engine 1. Computer unit. The ECU 40 calculates the amount of fuel to be supplied to each cylinder 2 based on, for example, the rotational speed of the engine 1 and the intake air amount (hereinafter may be referred to as a fuel injection amount), and the calculated fuel injection amount of fuel is calculated. The operation of each injector 30 is controlled so as to be injected into each cylinder 2 at an appropriate time. Examples of sensors connected to the ECU 40 include a crank angle sensor 41 and an air flow meter 8 that output a signal corresponding to the engine rotational speed (rotation speed) of the engine 1. In addition, various sensors are connected to the ECU 40, but their illustration is omitted.

  As shown in FIG. 2, in the engine 1, the condensate contained in the intake air flows into the # 1 cylinder 2 by the wraparound prevention wall 5a, and the inflow into the # 2 to # 4 cylinder 2 can be suppressed. . In this case, the combustion state of the # 1 cylinder 2 becomes worse than the combustion state of the # 2 to # 4 cylinders 2 due to the inflowing condensed water, and the torque generated in the # 1 cylinder 2 is # 2 to # 4. This is lower than the torque generated in each cylinder 2. Therefore, the ECU 40 sets the fuel injection timing for supplying fuel to the # 1 cylinder 2 so that the difference between the torque generated in the # 1 cylinder 2 and the torque generated in each of the # 2 to # 4 cylinders 2 becomes small. Control to improve the combustion state of cylinder # 1. FIG. 3 shows a combustion control routine that the ECU 40 repeatedly executes at a predetermined cycle during operation of the engine 1 so as to control the fuel injection timing of the cylinder # 1 in this way. By executing the control routine of FIG. 3, the ECU 40 functions as the combustion control means of the present invention.

  In the combustion control routine of FIG. 3, the ECU 40 first acquires the operating state of the engine 1 in step S11. The operating state of the engine 1 includes, for example, the rotational speed of the engine 1, the intake air amount, the flow rate of the first EGR gas, the flow rate of the second EGR gas, the temperature of the intake air flowing into the intake manifold 5, and the exhaust gas discharged from each cylinder 2. Is obtained. The flow rate of the first EGR gas may be detected by providing a flow rate sensor in the first EGR passage 20, for example, or may be estimated based on the opening degree of the first EGR valve 23, the intake air amount, and the like. What is necessary is just to acquire the flow volume of 2nd EGR gas similarly. The intake air temperature may be detected by providing a temperature sensor that outputs a signal corresponding to the intake air temperature to the intake manifold 5 in the intake passage 3 downstream of the intercooler 10. You may estimate based. The flow rate of the exhaust may be estimated based on, for example, the intake air amount and the fuel injection amount. In subsequent step S12, the ECU 40 calculates the fuel injection amount. The fuel injection amount may be calculated by a known calculation method that calculates based on the rotational speed of the engine 1 and the intake air amount. Therefore, detailed description is omitted.

  In the next step S13, the ECU 40 estimates the amount of condensed water flowing into the # 1 cylinder 2 based on the calculated fuel injection amount, the flow rate of the first EGR gas, the flow rate of the second EGR gas, and the intake air temperature. A method for estimating the amount of condensed water will be described with reference to FIGS. The ECU 40 first estimates the amount of moisture contained in the exhaust (hereinafter sometimes referred to as the amount of moisture in the exhaust) based on the fuel injection amount. FIG. 4 shows an example of the relationship between the fuel injection amount and the amount of moisture in the exhaust. Since the moisture in the exhaust is mainly generated by the combustion of fuel, it is considered that the amount of moisture in the exhaust increases as the fuel injection amount increases. Therefore, the relationship shown in FIG. 4 is obtained in advance by experiments or the like, stored in the ROM of the ECU 40 as a map, and the moisture content in the exhaust gas is estimated with reference to this map. Next, the ECU 40 may refer to the amount of moisture introduced to the intake passage 3 together with the EGR gas based on the estimated amount of moisture in the exhaust gas, the flow rate of the first EGR gas, and the flow rate of the second EGR gas (hereinafter referred to as recirculation moisture amount). .) As shown in FIG. 5, the amount of EGR gas recirculated to the intake passage 3, that is, the flow rate obtained by summing the flow rate of the first EGR gas and the flow rate of the second EGR gas (hereinafter, referred to as the total EGR gas amount). ) Increases the amount of reflux water. As is well known, the ratio of the exhaust gas recirculated to the intake passage 3 as EGR gas is represented by an EGR rate that is a value obtained by dividing the total EGR gas amount by the exhaust gas flow rate. Therefore, the ECU 40 calculates the EGR rate by dividing the total EGR gas amount by the exhaust gas flow rate, and calculates the recirculated water amount by multiplying the calculated EGR rate by the estimated water amount in the exhaust gas. Since most of the moisture contained in the intake air is contained in the recirculated EGR gas, the amount of intake water flowing into the intake manifold 5 is considered to be substantially the same. Thereafter, the ECU 40 estimates the amount of condensed water based on the amount of reflux water. As is well known, moisture is more likely to condense as the intake air temperature is lower. Therefore, the amount of moisture that condenses increases as the intake air temperature is lower. Therefore, the relationship between the intake air temperature shown in FIG. 6 and the condensate generation rate indicating the proportion of the moisture in the intake air that condenses to become condensed water is obtained in advance through experiments or the like as a map in the ROM of the ECU 40. The condensate generation rate is calculated based on this map. Then, the amount of condensed water is calculated by multiplying the calculated condensate generation rate and the amount of reflux water. By executing this process, the ECU 40 functions as the condensed water amount estimating means of the present invention.

  In subsequent step S14, the ECU 40 calculates a correction amount for the fuel injection timing based on the estimated amount of condensed water. As is well known, the torque generated in the cylinder 2 can be increased by advancing the fuel injection timing. Accordingly, the correction amount is set so that the fuel injection timing is advanced as the estimated amount of condensed water increases. Therefore, this correction amount is the advance amount of the fuel injection timing. FIG. 7 shows an example of the relationship between the condensed water amount and the correction amount. As shown in FIG. 7, the greater the amount of condensed water, the greater the correction amount, that is, the advance amount. The correction amount may be calculated by obtaining the relationship shown in FIG. 7 in advance through experiments or the like, storing it in the ROM of the ECU 40 as a map, and referring to this map.

  In the next step S15, the ECU 40 corrects the fuel injection timing of the # 1 cylinder 2 with the calculated correction amount. As described above, since this correction amount is an advance amount, the fuel injection timing is advanced by this correction. Thereafter, the current control routine is terminated. The fuel injection timing of the # 1 cylinder 2 corrected in step S15 is stored in the RAM of the ECU 40, and is used in a routine that the ECU 40 executes separately from the control routine of FIG. 3 in order to control the operation of each injector 30. Is done.

  By correcting the fuel injection timing of the # 1 cylinder 2 based on the amount of condensed water flowing into the # 1 cylinder 2 in this way, the combustion state deteriorated by the inflow of condensed water is improved. It is possible to reduce the difference between the generated torque and the torque generated in the cylinders # 2 to # 4 where the condensed water hardly flows. Therefore, it can suppress that the driving | running state of the engine 1 becomes unstable.

  The combustion control parameter that is controlled to improve the combustion state of the # 1 cylinder 2 is not limited to the fuel injection timing. For example, when a fuel injection amount of fuel is separately injected from the injector 30 and a pilot injection is performed in which a smaller amount of fuel is injected prior to the main fuel injection, the pilot injection is performed instead of the fuel injection timing. The amount of fuel that is sometimes injected may be controlled to improve the combustion state of cylinder # 1. As is well known, the torque generated in the cylinder 2 can be increased by increasing the amount of fuel during pilot injection. Therefore, when improving the combustion state with the fuel amount at the time of pilot injection, this fuel amount is corrected so that the amount of fuel at the time of pilot injection increases as the amount of condensed water flowing into the # 2 cylinder 2 increases. In this case, the fuel amount at the time of pilot injection corresponds to the combustion control parameter of the present invention.

  Further, the combustion state of the # 1 cylinder 2 can also be controlled by changing the number of pilot injections, and the torque generated in the cylinder 2 can be increased as the number is increased. Therefore, the number of pilot injections may be corrected so that the amount of condensed water flowing into the # 1 cylinder 2 increases. Note that the total fuel amount injected at the time of main fuel injection and the fuel amount injected at the time of pilot injection must be controlled to the fuel injection amount. Therefore, when the number of pilot injections is increased, the number is limited to that number. Is provided. As is well known, there is a lower limit for the amount of fuel that can be injected from the injector 30. Therefore, for example, the number of times that an appropriate amount of fuel can be injected from the injector 30 at the time of main fuel injection is set as the upper limit value even when the number of pilot injections corrected by the lower limit fuel amount is performed. In this case, the number of pilot injections corresponds to the combustion control parameter of the present invention.

  Furthermore, a glow plug capable of preheating the inside of the cylinder 2 may be provided in the # 1 cylinder 2, and the temperature in the cylinder 2 may be controlled by this glow plug to improve the combustion state of the # 1 cylinder 2. . In this case, as the amount of condensed water flowing into the # 1 cylinder 2 increases, the operation time of the glow plug is lengthened to raise the temperature in the cylinder 2. In this case, the temperature in the cylinder 2 corresponds to the combustion control parameter of the present invention.

  Combustion improvement of the # 2 cylinder 2 may be performed by combining control of parameters of fuel injection timing, fuel amount at the time of pilot injection, the number of pilot injections, and operation time of the glow plug. In this case, a priority order may be set according to which parameter should be controlled, and these parameters may be sequentially controlled according to the priority order.

  In the combustion control routine of FIG. 3, the correction amount of the fuel injection timing is calculated according to the estimated amount of condensed water. However, a sensor capable of detecting a physical quantity that changes in accordance with the combustion state in the cylinder is provided in the cylinder # 1. The correction amount may be calculated based on the detection result of the sensor. As a physical quantity that changes in accordance with the combustion state in the cylinder, for example, there is a pressure when fuel is burned in the cylinder 2, that is, a so-called combustion pressure. As is well known, the combustion pressure decreases as the combustion state deteriorates. Therefore, as shown in FIG. 8, the combustion pressure sensor 50 is provided as a combustion pressure detecting means for outputting a signal corresponding to the combustion pressure to the cylinder # 1 and fuel injection is performed based on the detection result of the combustion pressure sensor 50. The time may be corrected. As a method for calculating the correction amount, for example, a correspondence relationship between the operating state of the engine 1 and the target combustion pressure to be detected in the operating state is obtained in advance, and the combustion pressure detected by the combustion pressure sensor 50 and the engine The correction amount may be calculated based on the difference from the target combustion pressure set based on the operating state of 1. In this case, the combustion pressure sensor 50 corresponds to the combustion state detection means of the present invention.

  As a physical quantity that changes in accordance with the combustion state in the cylinder in addition to the combustion pressure, the quantity of ions generated when the fuel burns is known. Accordingly, an ion detection sensor serving as an ion detection means for detecting the amount of ions is provided in the # 1 cylinder 2 instead of the combustion pressure sensor 50, and the correction amount of the fuel injection timing is determined based on the detection result of the ion detection sensor. It may be calculated. In this case, the ion detection sensor functions as the combustion state detection means of the present invention.

  The combustion control parameter to be controlled based on the detection result of the combustion pressure sensor or the ion detection sensor is not limited to the fuel injection timing. As described above, the combustion state of the # 2 cylinder 2 can be improved even by changing the parameters of the fuel amount at the time of pilot injection, the number of pilot injections, and the operation time of the glow plug. The values of these parameters may be controlled based on the detection result.

  The present invention is not limited to the above-described form and can be implemented in various forms. For example, the present invention is not limited to a diesel engine, and may be applied to various internal combustion engines that use gasoline or other fuels. The present invention may also be applied to a spark ignition internal combustion engine that ignites a fuel mixture in a cylinder with a spark plug. In the spark ignition type internal combustion engine, the combustion state can also be changed by changing the ignition timing. Therefore, the ignition state may be controlled to improve the combustion state of the cylinder into which condensed water has flowed. The number of cylinders of the internal combustion engine to which the present invention is applied is not limited to four. The present invention may be applied to an internal combustion engine having a plurality of cylinders, for example, a 3, 6, 8, 10, 12 cylinder internal combustion engine. Further, the present invention is not limited to an internal combustion engine in which cylinders are arranged in series, and the present invention may be applied to a V-type internal combustion engine.

  A cylinder (hereinafter referred to as an “introduced cylinder”) that actively introduces condensed water by directing intake air is not limited to the # 1 cylinder, and other cylinders may be set. What is necessary is just to set suitably the cylinder of the position into which condensed water flows in into an introduction cylinder. As the introduction cylinder, for example, a cylinder located on an extension in the inflow direction of intake air from the intake pipe connected to the intake manifold may be set. Such a cylinder is determined according to, for example, the connection position and connection angle of the intake pipe connected to the intake manifold, and may be set according to the connection state of the intake pipe. Further, the wraparound prevention wall provided in the intake manifold may be appropriately changed in shape, number, and installation position in accordance with the set introduction cylinder. Furthermore, a plurality of cylinders may be set as introduction cylinders if the amount of inflowing condensed water can be adjusted. For example, two cylinders may be set as introduction cylinders as long as the condensed water in the intake air can flow in half.

The figure which shows the outline of the internal combustion engine in which the control apparatus which concerns on one form of this invention was integrated. The figure which expands and shows the inside of an intake manifold. The flowchart which shows the combustion control routine which ECU performs. The figure which shows an example of the relationship between the amount of fuel injection, and the moisture content in exhaust_gas | exhaustion. The figure which shows an example of the relationship between a total EGR gas amount and a recirculation | reflux water content. The figure which shows an example of the relationship between intake air temperature and condensed water generation rate. The figure which shows an example of the relationship between the amount of condensed water and correction | amendment amount. The figure which shows the modification of the control apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder 3 Intake passage 4 Exhaust passage 5 Intake manifold 5a A wrap-around prevention wall (guidance | derivation means, wall part)
14 EGR device 30 Injector (fuel injection valve)
40 Engine control unit (combustion control means, condensed water amount estimation means)
50 Combustion pressure sensor (combustion pressure detection means, combustion state detection means)

Claims (10)

A plurality of cylinders, an intake manifold that guides intake air to each of the plurality of cylinders, and an EGR device that extracts a part of the exhaust gas from the exhaust passage as EGR gas and recirculates it to the intake passage upstream of the intake manifold. In a control device applied to an internal combustion engine,
The induction means provided in the intake manifold and directing intake air to direct the intake air flowing into the intake manifold toward some cylinders of the plurality of cylinders, and generated in the some cylinders Combustion control means for controlling the value of a combustion control parameter that affects the combustion state of the internal combustion engine of the some cylinders so that the difference between the torque and the torque generated in the remaining cylinders is reduced. A control device for an internal combustion engine.   2. The control device for an internal combustion engine according to claim 1, wherein the guide means is provided in the intake manifold so that condensed water flowing into the intake manifold together with intake air is guided to the some cylinders. .   The internal combustion engine control according to claim 1 or 2, wherein a cylinder located on an extension of a center line of an intake pipe connected to the intake manifold is set in the some cylinders. apparatus.   The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the guide means is a wall portion provided according to a flow of intake air flowing into the intake manifold. The internal combustion engine further includes a fuel injection valve that is provided in each of the plurality of cylinders and injects fuel into the cylinders,
The combustion control means controls the operation of the fuel injection valve so that fuel is injected from the fuel injection valve, and a smaller amount than the main fuel injection prior to the main fuel injection from the fuel injection valve. 5. The fuel control parameter according to claim 1, wherein at least one of an amount of fuel injected in pilot injection in which fuel is injected from the fuel injection valve and the number of pilot injections is controlled as the combustion control parameter. The control apparatus for an internal combustion engine according to any one of the preceding claims. The internal combustion engine further includes a glow plug provided in each of the plurality of cylinders and capable of preheating the inside of the cylinder,
6. The internal combustion engine according to claim 1, wherein the combustion control unit controls an operation of the glow plug to control a temperature in the partial cylinder as the combustion control parameter. Engine control device. Condensed water amount estimating means for estimating the amount of condensed water flowing into the part of the cylinders together with intake air is further provided,
The combustion control means controls the value of the combustion control parameter so that the torque generated in the part of the cylinders increases as the amount of condensed water estimated by the condensed water amount estimation means increases. The control device for an internal combustion engine according to any one of claims 1 to 6.   The condensate amount estimation means is configured to determine the amount of fuel supplied to the plurality of cylinders, the flow rate of EGR gas recirculated by the EGR device, and the temperature of the intake air flowing into the intake manifold. The control device for an internal combustion engine according to claim 7, wherein the amount of condensed water flowing into the engine together with intake air is estimated. Combustion state detection means provided in the some cylinders for detecting the combustion state of the some cylinders;
The control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein the combustion control means controls the value of the combustion control parameter based on a detection result of the combustion state detection means.   The combustion state detecting means includes a combustion pressure detecting means for detecting a combustion pressure of the some cylinders, and an ion detecting means for detecting ions generated in the combustion gas when fuel burns in the some cylinders. The control device for an internal combustion engine according to claim 9, wherein the control device is at least one of them.

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