JP5626140B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a technical field of a control device for an internal combustion engine operated using, for example, light oil as fuel.

  The light oil used in this type of internal combustion engine may vary or decrease in cetane number depending on, for example, the manufacturing process and the destination. The fuel injection control of the internal combustion engine is based on a cetane number reference value in each country, for example. If the cetane number varies or decreases, there is a possibility that proper fuel injection control cannot be performed.

  In view of the above-described background, for example, Patent Document 1 discloses a technique for detecting a cetane number using an angular velocity of a crankshaft of an internal combustion engine. As a technique for improving the detection accuracy of the angular speed of the crankshaft, for example, Patent Document 2 discloses a technique of learning angular speed variation when the internal combustion engine is under a high load. Patent Document 3 discloses a technique for removing noise of a rotation 0.5th order frequency component of an internal combustion engine.

  On the other hand, as this type of internal combustion engine, there is known an engine capable of performing a reduced-cylinder operation in which the number of operating cylinders is reduced. For example, Patent Document 4 discloses a technique for increasing the load of an operating cylinder by performing a reduced-cylinder operation. Patent Document 5 discloses a technique of changing the filter characteristics used for the value detected by the air-fuel ratio sensor depending on whether or not the cylinder reduction operation is being performed.

JP 2007-321706 A JP-A-10-009040 JP 2003-286890 A JP 2010-255465 A JP 2006-097521 A

  In the technique for detecting the cetane number based on the crank angular velocity as disclosed in Patent Document 1 described above, the detection accuracy is reduced when the internal combustion engine is at a low load. As a countermeasure against this, for example, it is conceivable to increase the load of the internal combustion engine by the reduced cylinder operation as disclosed in Patent Document 4, but noise reduction or the like is performed on the crank angular velocity detected during the reduced cylinder operation. When performing the filter process, there may occur a situation in which an appropriate filter process cannot be performed because the number of operating cylinders is reduced. Thus, when appropriate filter processing cannot be performed, the technical problem that an incorrect cetane number will be detected as a result arises.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can suitably detect the cetane number of fuel used in the internal combustion engine.

  In order to solve the above-described problems, the control device for an internal combustion engine of the present invention is a control device for an internal combustion engine capable of executing a cetane number detection process for detecting a cetane number of fuel used in the internal combustion engine, and the cetane number When executing the detection process, the cylinder reduction control means for controlling the internal combustion engine to perform the cylinder reduction operation in which the number of operating cylinders is reduced and the output is maintained, and the internal combustion engine of the internal combustion engine during the cylinder reduction operation is controlled. Angular velocity detection means for detecting the angular speed of the crankshaft, filter processing means for performing a filter process on the output value of the detected angular speed using a filter corresponding to the number of operating cylinders of the internal combustion engine, and the filter process And a cetane number detection means for detecting the cetane number of the fuel in the internal combustion engine using the output value obtained by the above.

  An internal combustion engine control apparatus according to the present invention is a control apparatus for controlling an internal combustion engine such as a diesel engine mounted on a vehicle, for example, one or a plurality of CPUs (Central Processing Units), MPUs (Micro Processing Units). ), Various processors or various controllers, or further various storage means such as ROM (Read Only Memory), RAM (Random Access Memory), buffer memory or flash memory, etc. Various processing units such as Unit), various controllers, various computer systems such as a microcomputer device, and the like can be employed.

  In the control apparatus for an internal combustion engine according to the present invention, a cetane number detection process for detecting the cetane number of light oil that is a fuel used in the internal combustion engine can be executed. When executing the cetane number detection process, first, the internal combustion engine is controlled by the reduced cylinder control means so as to perform a reduced cylinder operation in which the number of operating cylinders is reduced and the output is maintained. According to the reduced-cylinder operation, the fuel injection amount per cylinder can be increased, and the load on the internal combustion engine can be temporarily increased. In the reduced-cylinder operation, it is not necessary to maintain the same output as that in the normal operation, and it is only necessary to maintain the output to the extent that the effect of increasing the load of the internal combustion engine described above can be obtained.

  Here, in particular, the accuracy of detecting the cetane number, which will be described later, tends to decrease greatly when the load on the internal combustion engine is small. Therefore, the detection accuracy of the cetane number can be increased by performing the reduced cylinder operation and increasing the load of the internal combustion engine. Note that the number of operating cylinders during the reduced-cylinder operation is set in advance based on the degree of load to be realized. Or you may calculate suitably using the various parameters in an internal combustion engine, etc. That is, the reduced-cylinder operation may be realized by realizing a specific number of operating cylinders, or may be realized by appropriately changing the number of operating cylinders.

  When the reduced-cylinder operation in the internal combustion engine is realized, the angular speed of the crankshaft of the internal combustion engine is detected by the angular speed detection means. The angular velocity of the crankshaft can be detected based on, for example, a crank angle signal detected by a crank position sensor or the like.

  When the angular velocity of the crankshaft is detected, filter processing is performed on the output value of the detected angular velocity by the filter processing means. The filtering process here is a process for more suitably detecting the cetane number, which will be described later, and specifically, an extraction process of the rotational 0.5th order vibration of the internal combustion engine that is an index of combustion instability, etc. It is done. Note that the rotational 0.5 order vibration of the internal combustion engine is more intense as the number of operating cylinders is smaller. Therefore, during the reduced-cylinder operation, the rotation 0.5th order vibration of the internal combustion engine can be extracted more suitably.

  Here, in the present invention, in particular, the filtering means performs the filtering process using a filter corresponding to the number of operating cylinders of the internal combustion engine. For example, a plurality of filters used for the filter processing are prepared so as to correspond to the number of operating cylinders that can be realized, and are appropriately selected according to the number of operating cylinders that are actually realized. As a result, even when the angular velocity detection component changes due to a change in the number of operating cylinders due to the reduced cylinder operation, it is possible to perform appropriate filtering.

  When the filter process is performed, the cetane number detection means detects the cetane number of the fuel using the output value subjected to the filter process. The cetane number detection means detects the cetane number based on, for example, a map indicating the correlation between the output value after filtering and the cetane number stored in advance. Note that the cetane number detected by the cetane number detection means may be a specific numerical value or a value indicating whether the cetane number is higher or lower than a predetermined reference value.

  As described above, according to the control apparatus for an internal combustion engine according to the present invention, when the cetane number detection process using the angular velocity of the crankshaft is performed, the reduced cylinder operation is realized and the filter corresponding to the number of operating cylinders is achieved. Is used for filtering. Therefore, it is possible to suitably detect the angular velocity and perform the filter process, and as a result, it is possible to detect the cetane number with high accuracy.

  In one aspect of the control apparatus for an internal combustion engine of the present invention, a fuel injection control means for performing fuel injection control in the internal combustion engine based on the detected cetane number is provided.

  According to this aspect, the detected cetane number is used for fuel injection control in the internal combustion engine. The fuel injection control means changes the fuel injection interval and the injection amount based on, for example, the detected cetane number. By performing the fuel injection control based on the cetane number in this way, for example, misfire due to deterioration of ignitability associated with a decrease in the cetane number is suppressed, and a suitable operation of the internal combustion engine can be realized. .

  In addition to the fuel injection control described above, a more suitable internal combustion engine can be realized by controlling the circulation exhaust amount in an exhaust gas recirculation (EGR) system, the supercharging rate in the supercharger, and the like. Driving can be realized.

  The effect | action and other gain of this invention are clarified from the form for implementing invention demonstrated below.

1 is a schematic configuration diagram conceptually showing a configuration of an engine system. It is a block diagram which shows the structure of ECU. 3 is a flowchart showing the operation of the control device for an internal combustion engine according to the embodiment. It is a graph which shows the correlation with an engine load and the detection accuracy of a cetane number. It is a graph which shows the correlation of engine rotation and crank angular velocity. It is a graph which shows the correlation with the rotation order of an engine, and crank angular velocity. It is a graph which shows the correlation with the rotation order of an engine, and a filter gain. It is a graph which shows the correlation of the rotation 0.5th-order vibration of an engine, and a cetane number.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the configuration of the engine system according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic configuration diagram conceptually showing the configuration of the engine system.

  In FIG. 1, an engine system 10 is mounted on a vehicle (not shown) and includes an ECU 100 and an engine 200.

  The ECU 100 is an electronic control unit that controls the entire operation of the engine 200 including a CPU, a ROM, a RAM, and the like, and is an example of the “control device for an internal combustion engine” according to the present invention. The ECU 100 is configured to be able to execute various controls according to a control program stored in, for example, a ROM. A specific configuration of the ECU 100 will be described in detail later.

  The engine 200 is a diesel engine using light oil as fuel, and is an example of the “internal combustion engine” according to the present invention. The engine 200 can convert the reciprocating motion of the piston 202 according to the explosive force generated when the air-fuel mixture containing fuel is compressed and ignited in the cylinder 201 into the rotational motion of the crankshaft 204 via the connection rod 203. It is configured to be possible.

  The crankshaft is an example of the “crankshaft” of the present invention, and a crank position sensor 205 that detects the rotational position of the crankshaft 204 is installed in the vicinity of the crankshaft 204. The crank position sensor 205 is electrically connected to the ECU 100, and the ECU 100 can calculate the engine speed NE of the engine 200 based on the rotational position of the crankshaft 204 detected by the crank position sensor 205. It is configured. Below, the principal part structure of the engine 200 is demonstrated with a part of the operation | movement.

  During combustion of fuel in the cylinder 201, air sucked from outside is purified by an air cleaner (not shown), then passes through the intake pipe 206, and enters the cylinder 201 when the intake valve 210 is opened via the intake port 209. Inhaled. At this time, the intake air amount related to the intake air sucked into the cylinder 201 is detected by an air flow meter (not shown), and is output to the ECU 100 as an electric signal at a constant or indefinite output timing.

  The intake pipe 206 is provided with a throttle valve 207 capable of adjusting the intake air amount. The throttle valve 207 is configured to be electrically and mechanically driven by a throttle valve motor 208 electrically connected to the ECU 100 according to, for example, an operation amount of an accelerator pedal (not shown). The throttle opening representing the open / closed state of the throttle valve 207 is detected by a throttle position sensor (not shown) electrically connected to the ECU 100 and is output to the ECU 100 at a constant or indefinite timing.

  Here, in particular, the fuel is stored in the fuel tank 212. The fuel tank 212 is provided with a float type fuel amount sensor 217 capable of detecting the remaining amount of fuel that represents the amount of fuel stored in the fuel tank 212. The fuel amount sensor 217 is electrically connected to the ECU 100, and the detected fuel amount is grasped by the ECU 100 at a constant or indefinite timing.

  On the other hand, the fuel stored in the fuel tank 212 is directly injected into the combustion chamber in the cylinder 201 by the injector 211. When fuel is injected through the injector 211, the fuel stored in the fuel tank 212 is first pumped from the fuel tank 212 through the delivery pipe 213 by the action of the feed pump 214 and supplied to the high-pressure pump 215.

  The common rail 216 is electrically connected to the ECU 100 and is configured to store high pressure fuel supplied from the upstream side (that is, the high pressure pump 215 side) up to a target rail pressure set by the ECU 100. Means. The common rail 216 is provided with a rail pressure sensor capable of detecting the rail pressure and a pressure limiter for limiting the amount of fuel accumulated so that the rail pressure does not exceed the upper limit value. The illustration is omitted.

  The above-described injector 211 in the engine 200 is mounted for each cylinder 201, and each is connected to the common rail 216 via a high-pressure delivery. Here, to supplement the configuration of the injector 211, the injector 211 includes an electromagnetic valve that operates based on a command from the ECU 100 and a nozzle (all not shown) that injects fuel when the electromagnetic valve is energized. The solenoid valve is configured to be able to control the communication state between the pressure chamber to which the high pressure fuel of the common rail 216 is applied and the low pressure side low pressure passage connected to the pressure chamber. The pressurizing chamber and the low pressure passage are communicated with each other, and the pressurizing chamber and the low pressure passage are shut off from each other when energization is stopped.

  On the other hand, the nozzle has a built-in needle for opening and closing the nozzle hole, and the fuel pressure in the pressure chamber urges the needle in the valve closing direction (direction in which the nozzle hole is closed). Therefore, when the solenoid chamber is energized, the pressurization chamber communicates with the low-pressure passage, and when the fuel pressure in the pressure chamber decreases, the needle rises in the nozzle and opens (opens the nozzle hole), so that the common rail 216 is opened. The high-pressure fuel supplied more can be injected from the injection hole. In addition, when the energization of the solenoid valve is stopped, the pressurization chamber and the low pressure passage are cut off from each other and the fuel pressure in the pressure chamber rises, and the needle is lowered in the nozzle to close the valve, thereby terminating the injection. It has become.

  The fuel injected into the cylinder 201 in this manner is mixed with the intake air sucked through the intake valve 210, and becomes the above-described air-fuel mixture. The air-fuel mixture burns by self-ignition in the compression step, and is opened as the exhaust valve 218 that opens and closes in conjunction with the opening and closing of the intake valve 210 as a burned gas or a partially unburned air-fuel mixture. It is configured to be guided to the exhaust pipe 220 via 219.

  Further, a DPF (Diesel Particulate Filter) 221 is installed in the exhaust pipe 220. The DPF 221 is configured to be able to collect and purify soot (soot) or smoke discharged from the engine 200 and PM (Particulate Matter). In addition, although illustration is abbreviate | omitted for the purpose of preventing complication of explanation, various sensors other than the above-mentioned sensor are arranged in engine 200, for example, a water temperature sensor which detects the cooling water temperature of engine 200, an engine A knock sensor that detects the knocking level of 200, an intake air temperature sensor that detects the intake air temperature that is the temperature of the intake air, an intake air pressure sensor that detects the intake pressure that is the pressure of the intake air, and the like are installed at optimal positions for each detection target. ing.

  Next, a specific configuration of the ECU 100 that is the control device for the internal combustion engine according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram showing the configuration of the ECU.

  In FIG. 2, the ECU 100 includes a detection start determination unit 110, a reduced cylinder control unit 120, a filter selection unit 130, an angular velocity detection unit 140, a filter processing unit 150, a cetane number detection unit 160, and a fuel injection control unit. 170.

  The detection start determination unit 110 performs determination for starting the cetane number detection process at an appropriate timing. For example, the detection start determination unit 110 detects the fuel remaining amount in the fuel tank 212 by the fuel amount sensor 217 (see FIG. 1), and then the fuel injection amount from the injector 211 exceeds the volume of the delivery pipe 213. It is determined to start the cetane number detection process at the determined timing.

  The cetane number of the fuel hardly changes over time in the fuel tank 212, for example, and varies greatly when fuels having different cetane numbers are mixed. Therefore, if the cetane number is detected when refueling in which different fuels can be mixed is performed, fluctuations in the cetane number can be reliably detected.

  However, immediately after refueling, the refueled fuel is not immediately injected from the injector 211, but first, the fuel remaining in the delivery pipe 213 (that is, fuel whose fuel has not changed due to refueling) is injected. Therefore, when the cetane number detection process is started immediately after refueling, there is a possibility that fluctuations in the cetane number cannot be detected properly. On the other hand, if the cetane number detection process is started after the fuel injection amount after refueling exceeds the volume of the delivery pipe 213, the process is performed at the timing when all the fuel remaining in the delivery pipe 213 is injected. Therefore, the cetane number can be detected more suitably. The determination can be made more accurately by adding the volumes of the feed pump 214, the high-pressure pump 215, and the common rail 216 to the volume of the delivery pipe 213.

  The reduced-cylinder control unit 120 is an example of the “reduced-cylinder control unit” of the present invention, and when the detection start determination unit 110 determines to start the cetane number detection process, the reduced cylinder control unit 120 operates with a reduced number of operating cylinders. The engine 200 is controlled to perform the reduced cylinder operation. The reduced cylinder control unit 120 stores data relating to the load of the engine 200 to be realized in the cetane number detection process, and the number of operating cylinders of the engine 200 is changed based on this data. The reduced-cylinder control unit 120 may be capable of realizing a plurality of types of reduced-cylinder operations with different numbers of operating cylinders.

  The filter selection unit 130 constitutes an example of the “filter processing unit” of the present invention together with the filter processing unit 150, and selects a filter used in the filter processing unit 150 from a plurality of preset filters. Particularly in the present embodiment, the filter selection unit 130 selects a filter according to the number of operating cylinders in the reduced cylinder operation realized by the reduced cylinder control unit 120. Note that the filter selection unit 130 may be configured as a filter generation unit that generates an appropriate filter in accordance with the number of operating cylinders, instead of selecting from filters prepared in advance.

  The angular velocity detector 140 is an example of the “angular velocity detector” of the present invention, and based on the crank angle signal output from the crank position sensor 205 (see FIG. 1), the angular velocity of the crankshaft 204 (hereinafter referred to as “crank” as appropriate). (Referred to as "angular velocity"). The crank angular velocity detected by the angular velocity detector 140 is output to the filter processor 150.

  The filter processing unit 150 performs a filter process on the output value of the crank angular velocity detected by the angular velocity detection unit 140 using the filter selected by the filter selection unit 130. As a result, the detected output value of the crank angular velocity is subjected to filter processing in accordance with the number of operating cylinders of the engine 200. The filter processing unit 150 can execute, for example, a process of extracting the rotational 0.5th order vibration of the engine 200 that is an index of combustion instability.

  The cetane number detection unit 160 is an example of the “cetane number detection means” of the present invention, and detects the cetane number of the fuel using the output value subjected to the filter processing. In the cetane number detection unit 160, for example, a map indicating the correlation between the output value after filtering and the cetane number is stored in advance. Note that the cetane number detected by the cetane number detection unit 160 may be a specific numerical value or a value indicating whether the cetane number is higher or lower than a predetermined reference value.

  The fuel injection control unit 170 is an example of the “fuel injection control means” in the present invention, and performs fuel injection control in the engine 200 based on the cetane number detected by the cetane number detection unit 160. Specifically, the injection amount and the injection interval of the fuel injected from the injector 211 in the engine 200 are appropriately changed according to the detected cetane number.

  The ECU 100 configured to include each part described above is an electronic control unit configured integrally, and all the operations related to each part are configured to be executed by the ECU 100. However, the physical, mechanical, and electrical configurations of the above-described parts according to the present invention are not limited thereto. For example, each of these parts includes various ECUs, various processing units, various controllers, microcomputer devices, and the like. It may be configured as a computer system or the like.

  Next, the operation of the control apparatus for an internal combustion engine according to the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the control device for the internal combustion engine according to the embodiment.

  In FIG. 3, when the control apparatus for an internal combustion engine according to the present embodiment operates, first, the detection start determination unit 110 determines whether or not fuel has been supplied to the fuel tank 212 (step S101). When refueling is detected (step S101: YES), it is determined whether or not the fuel injection amount after refueling has exceeded the volume of the delivery pipe 213 (step S102). That is, it is determined whether there is a possibility that the cetane number of the fuel injected from the injector 211 is fluctuating. Here, if it is determined that there is a possibility that the cetane number of the fuel is changing (step S102: YES), a cetane number detection process for detecting the cetane number of the fuel is started.

  In the cetane number detection process, first, the engine reduction control unit 120 controls the engine 200 to perform the cylinder reduction operation (step S103). During the reduced-cylinder operation, the load on the engine 200 increases because the number of operating cylinders decreases. Here, the relationship between the load of the engine 200 and the detection accuracy of the cetane number will be described with reference to FIG. FIG. 4 is a graph showing the correlation between engine load and cetane number detection accuracy.

  As shown in FIG. 4, it can be seen that the detection accuracy of the cetane number tends to increase as the load on the engine 200 increases. Therefore, if the load on the engine 200 is increased by performing the reduced-cylinder operation, the cetane number detection accuracy can be temporarily improved. The load of the engine 200 increases even when the fuel cut is performed, for example. However, when the cetane number detection process is to be performed at the time of the fuel cut, it is necessary to wait for the fuel cut to be automatically performed by deceleration or the like. It takes some time before the detection process is started. On the other hand, the reduced-cylinder operation performed in the present embodiment can be realized quickly by reducing the number of operating cylinders, so that the cetane number detection process can be started at an extremely appropriate timing.

  Returning to FIG. 3, when the reduced-cylinder operation is started, the angular velocity of the crankshaft 205 is detected by the angular velocity detector 140 (step S104). When the crank angular velocity is detected, a filter used for filter processing is selected in the filter selection unit 130 (step S105). Hereinafter, a filter selection method in the filter selection unit 130 will be specifically described with reference to FIGS. 5 to 7. FIG. 5 is a graph showing the correlation between engine rotation and crank angular velocity. FIG. 6 is a graph showing the correlation between the engine rotational order and the crank angular velocity. FIG. 7 is a graph showing the correlation between the engine rotational order and the filter gain. Here, a case will be described as an example in which a 6-cylinder engine has three operating cylinders by a reduced-cylinder operation.

In FIG. 5, the crank angular speed during normal operation with six operating cylinders changes as indicated by the solid line in the figure with respect to the rotation of the engine 200. On the other hand, the crank angular speed during the reduced-cylinder operation where the number of operating cylinders is 3 changes as indicated by the broken line in the drawing with respect to the rotation of the engine 200. Specifically, the frequency of the crank angular speed during the reduced cylinder operation is half that of the normal operation (that is, a value corresponding to the number of operating cylinders). Further, the amplitude of the crank angular speed during the reduced-cylinder operation is larger than that during the normal operation. In FIG. 6, the crank angular speed during the normal operation is the rotation indicated by the solid line in FIG. Has a third order peak. On the other hand, the crank angular speed during the reduced-cylinder operation has a peak at the 1.5th order of rotation as shown by the solid line in the drawing with respect to the rotational order of the engine 200. Thus, the vibration generated during normal combustion changes according to the number of operating cylinders.

  Here, when performing the filter process for extracting the rotational 0.5th order vibration, which is an index of combustion instability, the detected component of the angular velocity is different between the normal operation and the reduced cylinder operation, so the same filter was used. However, proper noise removal cannot be performed. In addition, when performing a plurality of types of cylinder reduction operations with different numbers of operating cylinders, the difference in the number of operating cylinders results in different angular velocity detection components, and similarly, appropriate noise removal cannot be performed.

  In FIG. 7, in order to cope with the change in the number of operating cylinders described above, a filter corresponding to the number of operating cylinders may be appropriately selected. That is, if the filter gain as shown by the solid line in the figure is appropriate during normal operation, the filter gain as shown by the broken line in the figure is applied during the reduced cylinder operation where the number of operating cylinders is three. do it. It should be noted that the filter gain corresponding to the number of operating cylinders may be applied in the same manner when performing a reduced cylinder operation where the number of operating cylinders is other than 3 (for example, when the number of operating cylinders is 2 or 4).

  Returning to FIG. 3 again, when a filter is selected, filter processing is performed in the filter processing unit 150 (step S106). The filter used for this filter process is selected according to the number of operating cylinders of the engine 200 as described above. Therefore, the output value of the crank angular velocity that has been subjected to the filtering process is a very appropriate value for detecting the cetane number.

  When the filter process is performed, the cetane number detection unit 160 uses the output value of the crank angular speed after the filter process (specifically, the value obtained by extracting the 0.5th-order rotation of the engine 200) as the fuel cetane number. Detection is performed (step S107). Hereinafter, a method of detecting the cetane number will be specifically described with reference to FIG. FIG. 8 is a graph showing the correlation between the engine rotation 0.5th order vibration and the cetane number.

  In FIG. 8, the cetane number detection unit 160 stores a map as shown in the figure in advance. Therefore, the cetane number can be detected easily and accurately from the value of the rotational 0.5th order vibration of the engine 200 extracted by the filtering process. Note that the cetane number detection unit 160 may detect the cetane number by a method other than the map as shown in the figure (for example, calculation using mathematical expressions).

  Returning to FIG. 3 again, when the cetane number of the fuel is detected, the reduction cylinder control unit 120 controls the engine 200 to end the reduction cylinder operation (step S108). That is, the cylinder reduction control unit 120 performs control so as to increase the number of operating cylinders of the engine. Thus, the reduced-cylinder operation only needs to be performed while the cetane number detection process is performed. More precisely, it is sufficient that the reduced-cylinder operation is performed only when the crank angular speed for detecting the cetane number is detected.

  Finally, fuel injection control based on the detected cetane number is performed by the fuel injection control unit 170 (step S109). For example, if the cetane number is detected as a relatively low value. Since it is considered that the ignitability of the fuel is deteriorated, the fuel injection control unit 170 performs the fuel injection control so as to improve the ignitability. Specifically, the engine 200 is controlled so as to shorten the fuel injection interval by the injector 211 or increase the fuel injection amount. According to such fuel injection control, the operating state of the engine 200 can be made appropriate according to the cetane number.

  Note that the cetane number detected by the cetane number detection unit 160 may be used for control other than the fuel injection control. That is, the purpose of use of the detected cetane number is not particularly limited.

  As described above, according to the control apparatus for an internal combustion engine according to the present embodiment, when performing the cetane number detection process, the reduced cylinder operation is performed and the filter process is performed using the filter corresponding to the number of operating cylinders. Is called. Therefore, it is possible to suitably detect the cetane number of the fuel used in the engine 200.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification. The control device is also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 100 ... ECU, 110 ... Detection start determination part, 120 ... Decrease cylinder control part, 130 ... Filter selection part, 140 ... Angular velocity detection part, 150 ... Filter process part, 160 ... Cetane number detection part, 170 ... Fuel injection control part, DESCRIPTION OF SYMBOLS 200 ... Engine, 204 ... Crankshaft, 205 ... Crank position sensor, 211 ... Injector, 212 ... Fuel tank, 217 ... Fuel amount sensor.

Claims (2)

A control device for an internal combustion engine capable of executing a cetane number detection process for detecting a cetane number of fuel used in the internal combustion engine,
A reduction-cylinder control means for controlling the internal combustion engine so as to perform a reduction-cylinder operation for reducing the number of operating cylinders and maintaining the output when performing the cetane number detection process;
Angular velocity detection means for detecting the angular velocity of the crankshaft of the internal combustion engine during the reduced cylinder operation;
Filter processing means for performing a filter process on the output value of the detected angular velocity using a filter corresponding to the number of operating cylinders of the internal combustion engine;
A control device for an internal combustion engine, comprising: cetane number detection means for detecting a cetane number of fuel in the internal combustion engine using an output value subjected to the filtering process.   2. The control device for an internal combustion engine according to claim 1, further comprising fuel injection control means for performing fuel injection control in the internal combustion engine based on the detected cetane number.

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