Internal combustion engine control method and apparatus for determining whether an injector has a malfunction, taking into account an influence of an air compressor

Abstract

An internal combustion engine control device for a vehicle, the internal combustion engine control device comprising: a crankshaft position sensor system (200) comprising at least one crankshaft position sensor and detecting an angular velocity of a crankshaft of an internal combustion engine, an air compressor (100) to which a driving force of the internal combustion engine is transmitted from an output end of the internal combustion engine, an injector (400) for injecting fuel, and a control device (300) which determines whether the injector (400) is malfunctioning based on a difference in a variation in the angular velocity of the crankshaft between a plurality of cylinders of the internal combustion engine, wherein the air compressor (100) and the output end of the internal combustion engine are arranged so that, immediately after fuel is injected by the injector (400) of the internal combustion engine, a drive torque of the air compressor (100) is periodically applied.

Description

Background of the inventionField of the invention

[0001] Exemplary embodiments of the present invention relate to an internal combustion engine control method and an internal combustion engine control device for determining whether an injector mounted in a vehicle internal combustion engine (eg in a motor vehicle internal combustion engine, in particular in an internal combustion engine of an automobile) has a malfunction, and more particularly relate to an internal combustion engine control method and an internal combustion engine control device capable of reducing an influence of an air compressor when determining whether an injector has a malfunction. Description of the technology used

[0002] An internal combustion engine, or combustion engine, which is the engine of a vehicle, generates power by combusting a mixture of ambient air and fuel in a combustion chamber. The fuel is injected into the combustion chamber through an injector controlled by an electronic control unit (hereinafter referred to as an "ECU"). If the injector malfunctions, the engine will not be properly synchronized, and the desired driving force may not be obtained. Vibration and failure to start (e.g., stalling) or restart may occur. Accordingly, it is very important to accurately determine whether the injector is malfunctioning or not.

[0003] In connection with methods of determining whether an injector is malfunctioning, Korean Patent Application Publication No. 2002-0022356 (March 27, 2002), also found under KR 10 2002 0 022 356 A, discloses a method of measuring a crankshaft angular velocity in a state where injectors in all cylinders of an internal combustion engine are turned off, utilizing a crankshaft angular velocity variation for each cylinder and a difference in the variation between cylinders. That is, it is determined that the injector is malfunctioning when the difference in the crankshaft angular velocity variation between cylinders is over a predetermined range.

[0004] The vehicle includes an air compressor for generating compressed air used for braking and a variety of air systems. The air compressor compresses and exhausts air by reciprocating its piston using power transmitted from a vehicle's internal combustion engine through engagement therewith. When the vehicle's air compressor is driven, the compressor's load is applied to the crankshaft at a specific angular interval per revolution of the engine, thereby affecting the angular velocity of the crankshaft. Accordingly, the angular velocity of the cylinder corresponding to the corresponding angular interval is reduced, and consequently, the injector for the corresponding cylinder may be mistakenly detected as malfunctioning.

[0005] Furthermore, US 4 667 634 A and US 4 779 595 A describe methods and systems for controlling an internal combustion engine to determine whether an injector is malfunctioning. Explanation of the invention

[0006] It is an object of the present invention to provide an internal combustion engine control method and an internal combustion engine control apparatus capable of reducing an influence of an air compressor based on a difference in a variation in the angular velocity of a crankshaft when determining whether an injector has a malfunction.

[0007] Other objects and advantages of the present invention will become apparent from the following description, and will become apparent with reference to the embodiments of the present invention. It will also be apparent to those skilled in the art to which the present invention pertains that the objects and advantages of the present invention may be realized by the means claimed and combinations thereof.

[0008] The above object is achieved by the features of the independent patent claims. Advantageous developments of the invention are described in the subclaims.

[0009] Accordingly, according to one embodiment of the present invention, an internal combustion engine control device for a vehicle (e.g. a motor vehicle, e.g. a passenger car) comprises: a crankshaft position sensor system which has at least one crankshaft position sensor and detects an angular velocity of a crankshaft of an internal combustion engine, an air compressor (e.g. air compressor) to which a driving force (e.g. torque) of the internal combustion engine is transmitted from an output end (e.g. output side) of the internal combustion engine, an injector for injecting fuel, and a control device which, based on a difference (hereinafter also just: "difference") in a variation (hereinafter also just: "variation") of the angular velocity of the crankshaft between a plurality ofA plurality (hereinafter also only "plurality") of cylinders of the internal combustion engine determines whether the injector has a malfunction (e.g. the injector fails or its operation is disturbed), wherein the air compressor and the output end of the internal combustion engine are arranged so that a drive torque of the air compressor is periodically applied or applied immediately after fuel has been injected by the injector of the internal combustion engine.

[0010] The driving force of the internal combustion engine may be transmitted by meshing an input end (e.g., drive side) of the air compressor with the output end of the internal combustion engine, and the air compressor may be configured to mesh with the output end of the internal combustion engine so that the driving torque of the air compressor is periodically applied immediately after fuel is injected by the injector of the internal combustion engine.

[0011] According to one embodiment of the present invention, an internal combustion engine control device for a vehicle comprises: a crankshaft position sensor system which has at least one crankshaft position sensor and detects an angular velocity of a crankshaft of an internal combustion engine, an air compressor (e.g. air compressor) to which a driving force (e.g. torque) of the internal combustion engine is transmitted from an output end (e.g. output side) of the internal combustion engine, an injector for injecting fuel, and a control device which determines whether the injector has a malfunction (e.g. the injector fails or its operation is disturbed) based on a variation in an angular velocity of the crankshaft between a plurality of cylinders of the internal combustion engine, wherein the control device detects an angular velocity of the crankshaft for each cylinder in each of specific rotation sections (e.g.specific sections of rotation of the crankshaft, also specific crankshaft revolution sections or specific crankshaft revolution ranges) when the internal combustion engine is operated, and determines whether the injector has a malfunction based on a variation in the angular velocity between the specific rotation sections of each cylinder, and wherein the air compressor and the output end of the internal combustion engine are arranged so that a drive torque of the air compressor is periodically applied or applied at a time (e.g. in a time interval) which is different from the time (e.g. the time interval) when the angular velocity is measured by the control device in the specific rotation sections to detect a malfunction of the injector.

[0012] The driving force of the internal combustion engine may be transmitted by engaging an input end (e.g., drive end) of the air compressor with the output end of the internal combustion engine, and the air compressor may be configured to engage with the output end of the internal combustion engine such that the driving torque of the air compressor is periodically applied at a time different from the time when the angular velocity is measured by the control device in the specific rotation sections to detect a malfunction of the injector.

[0013] The variation in the angular velocity between the specific rotational sections may be a difference between an angular velocity in a (rotational) section (e.g. first section) in which the crankshaft has a maximum angular velocity in / at each cylinder and an angular velocity in a (rotational) section different from this (rotational) section (e.g. second section).

[0014] According to another embodiment of the present invention, there is provided an engine control method for determining whether an injector for injecting fuel into an internal combustion engine of a vehicle has a malfunction, the vehicle having an air compressor driven by engagement with the internal combustion engine, the engine control method comprising: determining whether the injector has a malfunction based on a variation in an angular velocity of a crankshaft for each cylinder of the internal combustion engine, and determining whether the injector has a malfunction when a pressure at a rear end of the air compressor is equal to or less than a certain pressure.

[0015] According to a further embodiment of the present invention, there is provided an internal combustion engine control method for determining whether an injector for injecting fuel into an internal combustion engine of a vehicle has malfunctioned, the vehicle having an air compressor driven by engagement with the internal combustion engine, the internal combustion engine control method comprising: measuring an angular velocity of a crankshaft for each cylinder when the internal combustion engine is operating, calculating a variation in the angular velocity in / at each cylinder from a difference between angular velocities in specific rotational sections (e.g., specific sections of rotation of the crankshaft, also specific crankshaft revolution sections).specific crankshaft rotation ranges) in the measured angular velocity of the crankshaft for each cylinder, calculating a variation in the angular velocity of the crankshaft for each cylinder in a section other than the specific rotation sections when a variation in the angular velocity for any cylinder exceeds a first reference value, and determining whether the injector is malfunctioning when a variation in the angular velocity of the crankshaft between changed rotation sections exceeds a second reference value.

[0016] According to a further embodiment of the present invention, there is provided an internal combustion engine control method for determining whether an injector for injecting fuel into an internal combustion engine of a vehicle has malfunctioned, the vehicle having an air compressor driven by engagement with the internal combustion engine, the internal combustion engine control method comprising: measuring an angular velocity of a crankshaft for each cylinder at each cycle (e.g., in each stroke) when the internal combustion engine is operated, calculating a variation in an angular velocity in / at each cylinder from a difference between angular velocities in specific rotational sections (e.g., specific sections of rotation of the crankshaft, also specific crankshaft revolution sections).specific crankshaft revolution ranges) in the measured angular velocity of the crankshaft for each cylinder, and determining that the injector has malfunctioned when a variation in the angular velocity for any cylinder exceeds a reference value and a state in which the variation in the angular velocity exceeds the reference value is maintained for a predetermined time (e.g., at least for a predetermined period of time).

[0017] The internal combustion engine control method may further comprise, after calculating a variation in angular velocity in / at each cylinder, calculating a correction value (e.g., correction amount) of fuel injection (or fuel injection correction value) based on the calculated variation in angular velocity, wherein the fuel is supplied from the injector to each cylinder, and determining that the injector has malfunctioned when a correction value of fuel injection into any cylinder exceeds a reference value (e.g., fuel injection correction value reference value) and a state in which the correction value of fuel injection exceeds the reference value is maintained for a predetermined time (e.g., at least for a predetermined period of time).

[0018] The internal combustion engine control method may further comprise: determining whether the internal combustion engine is in an idling state and whether an engine coolant temperature is greater than or equal to a certain temperature, and determining whether a state in which the internal combustion engine is in the idling state and in which the engine coolant temperature is greater than or equal to the certain temperature is maintained for a certain time (eg, at least for a certain period of time), and wherein, when the state in which the internal combustion engine is in the idling state and in which the engine coolant temperature is greater than or equal to the certain temperature is maintained for a certain time, it can be determined whether the injector has a malfunction.

[0019] Determining whether the injector has a malfunction may include calculating a variation in angular velocity between specific rotational portions of each cylinder, and then calculating a correction value of fuel injection based on the calculated variation in angular velocity, wherein the fuel is supplied from the injector to each cylinder, and determining that the injector has a malfunction when a correction value of fuel injection into any cylinder exceeds a reference value and a state in which the correction value of fuel injection exceeds the reference value is maintained for a predetermined time.

[0020] The variation in angular velocity between the specific rotational sections may be a difference between an angular velocity in a section (e.g. first section) in which the crankshaft has a maximum angular velocity in / at each cylinder and an angular velocity in a section different from this section (e.g. second section).

[0021] If it is determined that the injector is malfunctioning, malfunction information may be communicated to a driver via a voice message or a video message, and a diagnostic trouble code (DTC) related to the malfunction information may be stored in a storage device in the vehicle.

[0022] If it is determined that the injector is not malfunctioning, an amount of fuel injected into each cylinder can be corrected based on the calculated fuel injection correction value. Short description of the drawings Fig. 1 is a block diagram showing a configuration of an internal combustion engine control device according to an embodiment of the present invention. Fig. 2 is a perspective view showing a configuration of an air compressor in the internal combustion engine control device according to an embodiment of the present invention. Fig. 3A and Fig. 3B shows a flowchart illustrating an internal combustion engine control method according to an embodiment of the present invention. Fig. 4A and Fig.4B shows a flowchart illustrating an engine control method according to another embodiment of the present invention. Fig. 5A and Fig. 5B shows a flowchart illustrating an engine control method according to another embodiment of the present invention. Fig. 6A and Fig. 6B show reference views for explaining an injector malfunction detection method to which the engine control apparatus and the engine control method according to embodiments of the present invention are applicable. Detailed description of specific embodiments

[0023] Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention may be embodied in various forms and should not be considered limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and to fully convey the scope of the present invention to those skilled in the art. In this disclosure, like reference numerals refer to similar parts throughout the various figures and embodiments of the present invention.

[0024] An injector malfunction detection method to which an engine control apparatus and an engine control method according to embodiments of the present invention are applicable will first be described with reference to Fig. 6A and Fig. 6B.

[0025] The injector malfunction detection method utilizes a difference in the variation of the angular velocity of a crankshaft. Preferably, the injector malfunction detection method utilizes a correction value (e.g., a correction amount) of fuel injection between cylinders to compensate for the difference in the variation of the angular velocity of the crankshaft.

[0026] Inter-cylinder fuel injection correction is a method of detecting a variation in the angular velocity of a crankshaft for each cylinder caused by compression, ignition, and combustion after injectors inject fuel into the respective cylinders by means of a crankshaft position sensor system having at least one crankshaft position sensor, and balancing (e.g., equalizing) a cylinder with other cylinders in synchronizing an internal combustion engine by increasing or decreasing an injection amount into the cylinder when the detected variation is compared between the cylinders and a difference in the variation in angular velocity exists.

[0027] As in Fig.6A, the crankshaft in cylinders 2 to 4 has the same angular velocity of 10 rad / s, but the crankshaft in cylinder 1 has a relatively low angular velocity of 8 rad / s. In this case, an ECU, as a control device having electrical circuits that perform various functions described below by executing instructions embedded therein, enables an injection quantity in cylinder 1 to be increased by a correction value in order to increase the relatively low angular velocity in cylinder 1, as shown in Fig. 6B.

[0028] Accordingly, when correcting fuel injection between cylinders, if a specific injector differs significantly from other injectors in terms of the injection correction value, it is determined that a physical abnormality occurs in the injector for the corresponding cylinder, and the injector is diagnosed as malfunctioning.

[0029] Since the angular velocity of the crankshaft is fast at the moment when fuel is burned in the cylinders and slow at the moment when combustion is completed, the angular velocity measured by the crankshaft position sensor is not maintained uniformly. Therefore, the range in which the crankshaft rotates once is regarded as (partial) sections (e.g., in the form of sectors or rotation angle sections) divided at regular time intervals, and the variation in angular velocity is calculated by comparing it between two specific sections among these sections. It is preferable to compare a required time in the fastest (angular) velocity section with a required time in the other section (e.g.,comparing a time to pass through the section of fastest angular velocity with a time to pass through the other section) in order to more precisely detect a variation in angular velocity.

[0030] Table 1 shows an example of this method. In a case where cylinder 1 is abnormal, the required time in a first section, in which the crankshaft rotation speed is the fastest, and the required time in a second section, which serves as the other section, are maintained at 40 and 70, respectively, for each of cylinders 2 to 4. However, for cylinder 1, the required time in the second section is relatively larger than that in the first section. In this case, a time variation (corresponding to the variation in angular velocity) is -90, which is a difference between 40 and 130, and the time variation for cylinder 1 has a deviation of 45 from the average value -45, which is an average of time variations of the four cylinders.

[0031] When performing fuel injection correction between cylinders, the fuel injection amount is corrected to compensate for the deviation. In this case, if the injection correction value exceeds a predetermined value, it is determined that the injector is malfunctioning. [Table 1] Time deviation at cylinder 1 Time average of the four cylinders Time change at cylinder 1 Time required for each section for cylinder 1 Time required for each section for cylinder 2 Time required for each section at cylinder 3 Time required for each section for cylinder 4 First section Second section First section Second section First section Second section First section Second section Normal 0 -30 -30 40 70 40 70 40 70 40 70 Abnormal 45 -45 -90 40 130 40 70 40 70 40 70

[0032] Fig. Fig. 2 is a perspective view showing an air compressor 100 in the internal combustion engine control device according to the embodiment of the present invention. As shown in Fig.As shown in Figure 2, the air compressor (e.g., air compressor) 100 is a device that generates compressed air used for vehicle brakes and a variety of air systems. The air compressor 100 is driven by a typical gear 111 and compresses and exhausts air by reciprocating a piston therein. Furthermore, the gear 11 on the air compressor 100 meshes with an engine output-side gear (e.g., engine driven-side gear) 112, and the air compressor 100 is driven by power transmitted from the engine through the meshing of the gears 111 and 112.

[0033] The pressure change when external air is sucked in and discharged by the periodic reciprocating motion of the piston in the air compressor 100 results in a periodic variation in the drive torque of the air compressor 100, thereby affecting the output side of the internal combustion engine. As a result, this variation affects the angular velocity of the crankshaft of the internal combustion engine and also affects the above-described determination of whether the injector is malfunctioning.

[0034] Fig. 1 is a block diagram showing the engine control device according to the embodiment of the present invention capable of reducing an influence of the air compressor 100.

[0035] As in Fig. 1, the internal combustion engine control device according to the embodiment of the present invention has the Fig.2, a crankshaft position sensor system 200 including at least one crankshaft position sensor, a controller (e.g., an ECU) 300 including electrical circuits that perform various functions described below by executing instructions embedded therein, and an injector 400. Preferably, the engine control device includes a fuel supply device, e.g., a high-pressure fuel pump 500 controlled by the controller 300 that supplies fuel to the injector, and an engine coolant temperature sensor 600 that detects a coolant temperature of the engine.

[0036] The crankshaft position sensor 200 is arranged near (e.g., adjacent) a sensor wheel 210 provided coaxially with the crankshaft. The sensor wheel 210 has a plurality of teeth 220 arranged along the outer circumference thereof. The crankshaft position sensor 200 detects the uneven teeth to determine a rotation angle and a rotational speed value (revolutions per minute, 1 / min) of the crankshaft, and outputs a pulse-shaped crankshaft signal (or crank signal) indicating the detected result to the controller 300. In this case, the teeth are not formed continuously along the circumference of the sensor wheel 210, but are spaced apart from a portion thereof. The crankshaft position sensor 200 detects the spaced apart portion as a missing tooth portion 230. With such a structure, it is possible to measure the angular velocity of the crankshaft.

[0037] The controller 300 receives the crankshaft signal from the crankshaft position sensor 200, calculates the angular velocity of the crankshaft using the received result, and controls the injector 400 and the fuel pump 500 to correct the amount of fuel injected by the injector 400 attached to each cylinder based on the calculated result. The controller 300 determines whether the injector 400 is malfunctioning, as described above, based on the engine coolant temperature information transmitted from the engine coolant temperature sensor 600. Furthermore, the controller 300 controls the operation of the air compressor 100 to generate a desired compressed air.

[0038] According to the embodiment of the present invention, the gear 111 on the air compressor 100 is configured to mesh with the engine output-side gear 112, so that the drive torque of the air compressor 100 is applied (i.e., the drive torque periodically rises above a certain level) immediately after fuel is injected by the injector 400 of the engine. The engine has the highest output torque immediately after the fuel is injected by the injector 400. Thus, compared with the other rotation section (e.g., second (rotation) section) of the engine, it is possible to significantly suppress the influence of the drive torque of the air compressor, even though the drive torque of the air compressor 100 has risen above a certain level at the above time.

[0039] This can be achieved by engaging the gear 111 on the air compressor 100 with the internal combustion engine output-side gear 112 so that the top dead center of the piston in the air compressor 100 substantially coincides with the top dead center of the piston in the cylinder of the internal combustion engine (or both dead centers substantially coincide).

[0040] Alternatively, according to the embodiment of the present invention, the gear 111 on the air compressor 100 is configured to mesh with the engine output-side gear 112 so that the drive torque is periodically applied at a time different from the time when the angular velocity is measured by the controller 300 in the specific rotation sections to detect a malfunction of the injector 400.

[0041] As described above, the control device 300 compares an angular velocity (or a required time) between two specific sections among the rotation sections of the crankshaft to obtain a variation in the angular velocity of the crankshaft. For example, as shown in Table 1, the control device 300 compares an angular velocity (or a required time) between the first section, in which the angular velocity of the crankshaft is fast, and the second section, which is one of the other sections. The drive torque of the air compressor 100 is increased at a specific cycle (e.g., at a specific stroke). If the time when the drive torque is applied is outside the time when the angular velocity is detected in a section (e.g.,Therefore, since the time period in which drive torque is applied and the time period in which the angular velocity is detected in a section do not overlap, a section in which a rotational speed (rpm) of the internal combustion engine is reduced due to the drive torque of the air compressor 100 is excluded when determining whether the injector 400 is malfunctioning. Accordingly, it is possible to exclude the influence of the drive torque of the air compressor 100 when determining whether the injector 400 is malfunctioning.

[0042] This can be achieved by engaging the gear 111 on the air compressor 100 with the internal combustion engine output side gear 112 so that the top dead center of the piston in the air compressor 100 and the top dead center of the piston in the cylinder of the internal combustion engine are within a certain angular range (e.g., 120° to 150°).

[0043] Fig.3A and Fig. 3B shows a flowchart illustrating an internal combustion engine control method according to an embodiment of the present invention.

[0044] As in Fig.As shown in Figure 3A, a controller 300 first determines whether a vehicle speed sensor system, such as a crankshaft position sensor system 200 including at least one crankshaft position sensor, and the power supply terminal (e.g., power terminal) of an injector 400 are malfunctioning (S100). Component failure can be checked, for example, by diagnostic information using an ASIC (application-specific IC) provided in an ECU system for controlling the operation of the parts. If the parts are malfunctioning, it is fundamentally impossible to determine whether the injector 400 is malfunctioning, or it may be possible to make an incorrect decision. Therefore, it is preferable to first determine whether these parts are malfunctioning.

[0045] If it is determined that the vehicle speed sensor and the power supply terminal of the injector 400 are not malfunctioning, the controller determines whether a control permission condition related to an engine state and a coolant temperature is satisfied (S110). To accurately determine whether the injector 400 is malfunctioning, it is preferable to exclude, as much as possible, factors other than the injector 400 that may affect the angular velocity of the crankshaft. Accordingly, it is preferable that the engine be in an idling state and not in a cold state (or cold state), with the engine coolant temperature maintained above a certain temperature (e.g., at a temperature greater than or equal to 70°C).

[0046] In addition, in order to more stably and reliably determine whether the injector 400 is malfunctioning, the control permission condition specified in step S110 may preferably be maintained for a certain time (e.g., more than 10 minutes) after it is executed (S120). However, the time required to fill an air tank by an air compressor 100 is excluded from the maintenance time.

[0047] In the embodiment of the present invention, the air compressor 100 has a pressure sensor on its downstream side. The controller 300 receives pressure information at the rear end (e.g., downstream end) of the air compressor 100 from the pressure sensor and determines whether the injector 400 is malfunctioning only when the pressure at the rear end of the air compressor 100 is less than or equal to a certain pressure. The air compressor 100 is not always operating. Therefore, the control device 300 does not determine whether the injector 400 is malfunctioning when the pressure at the rear end of the air compressor 100, which is generated while the air compressor is operated to fill the air tank provided in the vehicle with air, exceeds a certain level, and determines whether the injector 400 is malfunctioning only when the pressure applied to the rear end of the air compressor 100 is removed.

[0048] In this case, it is possible to exclude the influence of the drive torque of the air compressor 100 when determining whether the injector 400 has a malfunction.

[0049] If the pressure at the rear end of the air compressor 100 is less than or equal to the specified pressure, the controller 300 detects a variation in the angular velocity of the crankshaft for each cylinder in a specific (rotational) section to determine whether the injector 400 is malfunctioning (S140). To this end, it is preferable that the injectors for a plurality of cylinders are off in turn, and the angular velocity of the crankshaft is detected using the crankshaft position sensor 200.In this case, the specific section is selected as one of a section where the angular velocity is fastest (a section where fuel is injected near the piston top dead center) and other sections, and it is possible to detect the variation in the angular velocity using an angular velocity in each of the sections or a required time in the section.

[0050] When the variation in the angular velocity of the crankshaft is detected for each cylinder in the specific section, the controller 300 obtains an average value of the detected angular velocities for a plurality of cylinders and obtains a difference in the variation in the angular velocity of the crankshaft for each cylinder from the average value (S150). The controller 300 calculates a fuel injection correction value for each cylinder from the difference in the variation in the angular velocity of the crankshaft to compensate for the difference.

[0051] After the fuel injection correction value is calculated for each cylinder, the control device 300 compares the fuel injection correction value with a predetermined reference value. If, among a plurality of cylinders, there is a cylinder in / for which the fuel injection correction value exceeds the predetermined reference value, the control device 300 determines that the injector 400 of the cylinder is malfunctioning (S170 and S180).

[0052] According to the embodiment of the present invention, when it is determined that the cylinder in which the injector 400 is malfunctioning is present, the controller 300 may output a voice message through a speaker installed in the vehicle or a video message on a screen, such as an instrument panel installed in the vehicle, to inform a driver that the injector is malfunctioning. Through this process, the driver can recognize that a fuel supply system is malfunctioning and take appropriate measures, such as replacement (S190).

[0053] According to the embodiment of the present invention, the control device 300 warns of an injector malfunction and stores a diagnostic trouble code (DTC) related to a malfunctioning cylinder and a malfunction of the injector 400 for a corresponding cylinder in a storage device in the vehicle. This process makes it possible to easily identify the cause of the problem in a subsequent maintenance procedure and reduce vehicle maintenance costs because only a malfunctioning or non-functioning injector is replaced.

[0054] Fig. 4A and Fig. 4B shows a flowchart illustrating an internal combustion engine control method according to another embodiment of the present invention. A detailed description of components and contents in the flowchart of Fig. 4A and Fig.4B, which are identical to those in the flowchart of Fig. 3A and Fig. 3B is omitted.

[0055] Steps S200 to S220 in Fig. 4A are steps of determining the control permission condition, which corresponds to steps S100 to S120 in Fig. 3A. If the control permission condition is satisfied in steps S200 to S220, the controller 300 determines whether the injector 400 is malfunctioning (S230).

[0056] To determine whether the injector 400 is malfunctioning, the controller 300 detects a variation in the angular velocity of the crankshaft for each cylinder in a specific (rotation) section (S240), similar to step S140 in Fig. 3.

[0057] The controller 300 determines whether a cylinder in / at which the angular velocity in the crankshaft in the specific section exceeds a predetermined first reference value exists (S250). The first reference value is a threshold value for the variation in the angular velocity of the crankshaft to determine whether the injector 400 is malfunctioning, and is predetermined according to the specification of the injector 400 or the internal combustion engine mounted on the vehicle. Furthermore, in this step, the section in which the variation in the angular velocity of the crankshaft is detected preferably uses a section (first section) in which the rotational speed of the crankshaft is the fastest and one (second section) of other sections excluding the section (e.g., a section other than the section in which the rotational speed of the crankshaft is the fastest).

[0058] If the cylinder in / at which the variation in the angular velocity of the crankshaft in the specific section exceeds the first reference value in the specific section is present, the controller 300 does not (immediately) determine the injector malfunction, but changes (e.g., shifts) the angular velocity variation detection section (S260) and detects a variation in the angular velocity of the crankshaft for each cylinder in the changed section (S270). If the time when the drive torque of the air compressor 100 is applied is in the angular velocity variation detection section in step S240, then even though there is no malfunction of the injector 400, the angular velocity variation detected in step S240 may exceed the first reference value because it is subject to the drive torque of the air compressor 100.To prevent this, the controller 300 changes a detection section to check again whether the injector 400 has a malfunction.

[0059] For this purpose, for example, the variation of the angular velocity is detected by comparing the angular velocity between a third and a fourth section except for the first and the second section used in step S240 (e.g., the third and the fourth section are different from the first and the second section, respectively), or by detecting the angular velocity in the first section in which the rotational speed is the fastest and the angular velocity in the other sections except for the second section to compare them.

[0060] The controller 300 determines whether the variation in the angular velocity of the crankshaft for each cylinder detected in the changed section exceeds a predetermined second reference value (S280). If the injector 400 physically fails, there is a difference in the variation in the angular velocity of the crankshaft between the cylinder in which the injector 400 malfunctions and another cylinder, even if the variation in the angular velocity in the crankshaft is detected in the changed section.

[0061] Here, the second reference value may be equal to or different from the first reference value, depending on the position or combination of the changed detection sections.

[0062] If the variation in the crankshaft angular velocity detected in the changed portion for each cylinder is determined to exceed the predetermined second reference value, then the controller 300 can directly determine that the injector 400 is malfunctioning. Furthermore, similar to steps S150 to S170, the controller 300 can calculate a fuel injection correction value for each cylinder based on the value obtained by detecting a difference in the crankshaft angular velocity variation for each cylinder, and determine whether the fuel injection correction value exceeds a predetermined value to determine whether the injector is malfunctioning (S290 to S310).

[0063] If the injector is determined to be malfunctioning, then warning a driver of the malfunction of the injector 400 and recording an error code are similar to the operations in the embodiment of Fig. 3.

[0064] Fig. 5A and Fig. 5B shows a flowchart illustrating an internal combustion engine control method according to another embodiment of the present invention. A detailed description of components and contents in the flowchart of Fig. 5A and Fig. 5B, which are identical to those in the flowchart of Fig. 3A to 4B are omitted.

[0065] Steps S400 to S420 in Fig. 5A are steps of determining the control permission condition, which corresponds to steps S100 to S120 in Fig.3A. If the control permission condition is satisfied in steps S400 to S420, the controller 300 determines whether the injector 400 is malfunctioning (S430).

[0066] To determine whether the injector 400 is malfunctioning, the controller 300 detects a variation in the angular velocity of the crankshaft for each cylinder in a specific (rotation) section (S440), similar to step S140 in Fig. 3, and obtains (e.g. similar to step S150 in Fig. 3) a difference in the variation of the angular velocity of the crankshaft for each cylinder based on the detected variation in the angular velocity of the crankshaft for each cylinder (S450).

[0067] The controller 300 calculates a fuel injection correction value for each cylinder from the difference in the variation of the angular velocity of the crankshaft for each cylinder to compensate for the difference (S460), and determines whether the fuel injection correction value exceeds a predetermined value (S470).

[0068] This procedure is the same as the procedure for determining whether the injector has a malfunction, which is described with reference to Fig. 3A to 4B. In this embodiment of the present invention, the method determines whether the fuel injection correction value exceeds the predetermined value and then maintains it for a predetermined time (S480 and S490).

[0069] As described above, the drive torque of the air compressor 100 is increased by a predetermined level (has a peak value) at a specific cycle (e.g., at a specific stroke), thereby generating a load. Therefore, the influence of the drive torque of the air compressor 100 is maximized near the peak value, while it is significantly reduced in the remaining range.

[0070] On the other hand, if the injector 400 malfunctions, the fuel injection correction value is not decreased over time but remains constant for a certain period of time. Accordingly, the method of the embodiment of the present invention determines whether the calculated fuel injection correction value exceeds the predetermined value and then maintains it for a predetermined period of time. If the aforementioned condition persists for a certain period of time, it is determined that the injector 400 malfunctions (S500).

[0071] If the injector is determined to be malfunctioning, then warning a driver of the malfunction of the injector 400 and recording an error code are similar to the operations in the embodiment of Fig. 3 (S510).

[0072] According to embodiments of the present invention, it is possible to prevent the erroneous determination of whether the injector is malfunctioning due to the variation in drive torque caused during operation of the air compressor. Consequently, it is possible to prevent an increase in vehicle maintenance costs due to unnecessary component replacement.

[0073] According to exemplary embodiments of the present invention, it is possible to suppress an increase in vehicle maintenance costs due to unnecessary component replacement by preventing erroneous determination of whether the injector has malfunctioned due to the variation in drive torque caused during operation of the air compressor.

Claims

[1] An internal combustion engine control device for a vehicle, the internal combustion engine control device comprising: a crankshaft position sensor system (200) comprising at least one crankshaft position sensor and detecting an angular velocity of a crankshaft of an internal combustion engine, an air compressor (100) to which a driving force of the internal combustion engine is transmitted from an output end of the internal combustion engine, an injector (400) for injecting fuel, and a control device (300) which determines whether the injector (400) is malfunctioning based on a difference in a variation in the angular velocity of the crankshaft between a plurality of cylinders of the internal combustion engine, wherein the air compressor (100) and the output end of the internal combustion engine are arranged so that, immediately after fuel is injected by the injector (400) of the internal combustion engine, a drive torque of the air compressor (100) is periodically applied. [2] The internal combustion engine control device according to claim 1, wherein: the driving force of the internal combustion engine is transmitted by engagement of an input end of the air compressor (100) with the output end of the internal combustion engine, and the air compressor (100) is arranged to engage the output end of the internal combustion engine so that, immediately after fuel has been injected by the injector (400) of the internal combustion engine, the drive torque of the air compressor (100) is applied periodically. [3] An internal combustion engine control device for a vehicle, the internal combustion engine control device comprising: a crankshaft position sensor system (200) comprising at least one crankshaft position sensor and detecting an angular velocity of a crankshaft of an internal combustion engine, an air compressor (100) to which a driving force of the internal combustion engine is transmitted from an output end of the internal combustion engine, an injector (400) for injecting fuel, and a control device (300) which determines whether the injector (400) is malfunctioning based on a variation in an angular velocity of the crankshaft between a plurality of cylinders of the internal combustion engine, wherein the control device (300) measures an angular velocity of the crankshaft for each cylinder in each of specific rotational sections when the internal combustion engine is operated, and determines whether the injector (400) is malfunctioning based on a variation in the angular velocity between the specific rotational sections of each cylinder, and wherein the air compressor (100) and the output end of the internal combustion engine are arranged so that a drive torque of the air compressor (100) is periodically applied at a time different from the time when the angular velocity is measured by the control device in the specific rotation sections to detect a malfunction of the injector. [4] An internal combustion engine control device according to claim 3, wherein: the driving force of the internal combustion engine is transmitted by engagement of an input end of the air compressor (100) with the output end of the internal combustion engine, and the air compressor (100) is arranged to engage the output end of the internal combustion engine so that the drive torque of the air compressor (100) is periodically applied at a time different from the time when the angular velocity is measured by the control device (300) in the specific rotation sections to detect a malfunction of the injector. [5] An internal combustion engine control apparatus according to claim 3 or 4, wherein the variation in angular velocity between the specific rotational sections is a difference between an angular velocity in a section in which the crankshaft has a maximum angular velocity in each cylinder and an angular velocity in a section different from that section. [6] An internal combustion engine control method which determines whether an injector (400) for injecting fuel into an internal combustion engine of a vehicle has a malfunction, the vehicle having an air compressor (100) which is driven by engagement with the internal combustion engine, the internal combustion engine control method comprising: Determining whether the injector (400) is malfunctioning based on a variation in an angular velocity of a crankshaft for each cylinder of the internal combustion engine, and Determining whether the injector (400) is malfunctioning when a pressure at a rear end of the air compressor (100) is equal to or less than a certain pressure. [7] An internal combustion engine control method which determines whether an injector (400) for injecting fuel into an internal combustion engine of a vehicle has a malfunction, the vehicle having an air compressor (100) which is driven by engagement with the internal combustion engine, the internal combustion engine control method comprising: Measuring an angular velocity of a crankshaft for each cylinder when the internal combustion engine is operating, Calculating (S240) a variation in the angular velocity for each cylinder from a difference between angular velocities in specific rotational sections in the measured angular velocity of the crankshaft for each cylinder, Calculating (S270) a variation in the angular velocity of the crankshaft for each cylinder in a section other than the specific rotation sections when a variation in the angular velocity for any cylinder exceeds a first reference value (S260), and Determining (S320) whether the injector (400) is malfunctioning when a variation in the angular velocity of the crankshaft between changed rotation sections exceeds a second reference value (S280). [8] An internal combustion engine control method which determines whether an injector (400) for injecting fuel into an internal combustion engine of a vehicle has a malfunction, the vehicle having an air compressor driven by engagement with the internal combustion engine, the internal combustion engine control method comprising: Measuring an angular velocity of a crankshaft for each cylinder at each cycle when the internal combustion engine is operating, Calculating (S440) a variation in an angular velocity at each cylinder from a difference between angular velocities in specific rotational sections in the measured angular velocity of the crankshaft for each cylinder, and Determining (S500) that the injector (400) has malfunctioned when a variation in angular velocity in any cylinder exceeds a reference value and a state in which the variation in angular velocity exceeds the reference value is maintained for a predetermined time. [9] An internal combustion engine control method according to claim 8, further comprising: after calculating a variation in angular velocity in each cylinder, calculating (S460) a correction value of fuel injection based on the calculated variation in angular velocity, wherein the fuel is supplied from the injector (400) to each cylinder, and Determining (S500) that the injector (400) has a malfunction when a fuel injection correction value in any cylinder exceeds a reference value (S470) and a state in which the fuel injection correction value exceeds the reference value is maintained for a predetermined time (S480). [10] An internal combustion engine control method according to any one of claims 6 to 8, further comprising: Determining (S110; S210; S410) whether the internal combustion engine is in an idle state and whether an internal combustion engine coolant temperature is greater than or equal to a certain temperature, and Determining (S120; S220; S420) whether a state in which the internal combustion engine is in the idling state and in which the internal combustion engine coolant temperature is greater than or equal to the specified temperature is maintained for a specified time, and wherein, when the state in which the internal combustion engine is in the idling state and in which the internal combustion engine coolant temperature is greater than or equal to the predetermined temperature is maintained for a predetermined time, it is determined whether the injector (400) has a malfunction. [11] An internal combustion engine control method according to claim 6 or 7, wherein determining whether the injector (400) is malfunctioning comprises: Calculating a variation in angular velocity between specific rotational sections of each cylinder, and then calculating a correction value of fuel injection based on the calculated variation in angular velocity, wherein the fuel is supplied from the injector (400) to each cylinder, and Determining that the injector (400) is malfunctioning when a fuel injection correction value in any cylinder exceeds a reference value and a state in which the fuel injection correction value exceeds the reference value is maintained for a predetermined time. [12] An internal combustion engine control method according to claim 11, wherein the variation in angular velocity between the specific rotation sections is a difference between an angular velocity in a section in which the crankshaft has a maximum angular velocity in each cylinder and an angular velocity in a section different from that section. [13] An internal combustion engine control method according to any one of claims 6 to 12, wherein, when it is determined that the injector (400) is malfunctioning, malfunction information is transmitted to a driver by means of a voice message or a video message (S190; S330; S510), and a diagnostic trouble code (DTC) related to the malfunction information is stored in a storage device in the vehicle. [14] An internal combustion engine control method according to any one of claims 6 to 13, wherein, when it is determined that the injector (400) does not malfunction, an amount of fuel injected into each cylinder is corrected based on the calculated fuel injection correction value.

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