JP2010096082A - Throttle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throttle control device for reliably preventing exhaust gas performance from being lowered and an abnormal output from occurring at a next trip by reliably detecting a full close abnormality caused when a diesel throttle is not fully closed. <P>SOLUTION: This throttle control device for controlling the diesel throttle 14 which is installed in the intake passage 4 of an engine 1 and opened and closed by a stepping motor 18 controls to close the diesel throttle 14 when the engine 1 is stopped by turning off an IG switch 48. When the time T required for the rotational speed of the engine to fall to zero from a base P when the engine 1 is stopped by turning off the IG switch 48 is within an allowable threshold Q which is elapsed X seconds from the base P, the throttle control device determines that "full close abnormality has not occurred". If the time exceeds the allowable threshold Q which is elapsed X seconds from the base P, the throttle control device determines that "full close abnormality has occurred". <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a throttle control device that controls a throttle provided in an intake pipe of an engine mounted on, for example, an automobile.

2. Description of the Related Art Conventionally, there is known an engine throttle control device that controls a throttle opening by driving an electric motor in accordance with an accelerator pedal depression amount or the like (see, for example, Patent Document 1).
JP 2006-329044 A

  By the way, in an engine throttle control device mounted on an automobile or the like, the throttle is controlled to close to the fully closed position when the engine is stopped by turning off the ignition switch. The reference position of the reduction and throttle opening can be detected smoothly. In that case, the allowable range of the fully closed angle of the throttle is defined in the control, but it is necessary to set the allowable range of the fully closed angle of the throttle in a wide range in consideration of various variations.

  For this reason, even if a full-close abnormality has occurred in which the throttle is not fully closed due to foreign matter biting in at the full-close position of the throttle, the temporary full-close position of the throttle (a position that cannot be fully closed) ) Within the permissible full-close angle range, there is a risk that the throttle will be misrecognized as the full-close position. In this case, an erroneous full-closed position learning is performed in which the throttle is learned to be in the fully closed position (reference position) even though the throttle is not fully closed, and the next trip (next ignition switch From on to off), control is performed with the throttle opening deviated, resulting in a reduction in exhaust gas performance and output abnormality.

  The present invention has been made in view of such points, and the object of the present invention is to reliably detect a fully closed abnormality in which the throttle is not fully closed, and to reliably reduce exhaust gas performance and output abnormality in the next trip. It is an object of the present invention to provide a throttle control device that can prevent the above.

  In order to achieve the above object, the present invention is based on the premise of a throttle control device that is provided in an intake pipe of an engine and controls a throttle that is opened and closed by an electric motor, and the throttle, for example, when the engine is stopped by turning off an ignition switch, The diesel throttle provided in the intake pipe of the diesel engine is controlled to close. Furthermore, a rotation speed detection means for detecting the rotation speed of the engine is provided. Based on the engine speed reduction characteristic detected by the engine speed detection means when the engine is stopped by turning off the ignition switch, for example, the time required for the engine speed to become zero, the diesel throttle An abnormality determining means for determining a fully closed abnormality is provided.

  Because of this specific matter, it is determined whether the throttle is fully closed such as a diesel throttle based on the engine speed reduction characteristics such as the time required for the engine speed to reach zero when the engine is stopped by turning off the ignition switch. If the throttle is not fully closed due to foreign matter or the like being caught at the throttle fully closed position, the throttle will not be closed and the throttle fully closed flow will increase. It turns out that the time required for the rotational speed to reach zero increases, and the engine rotational speed lowering characteristics deteriorate, and it is determined that the throttle is abnormally closed. For this reason, if a fully closed abnormality occurs when the engine is stopped due to the ignition switch being turned off, the time required for the engine speed to become zero is increased, and thus the throttle fully closed abnormality is reliably detected. Therefore, the temporary fully closed position of the throttle due to the fully closed abnormality is not erroneously recognized as the fully closed position of the throttle. This avoids an erroneous learning of the fully closed position, in which it is learned that the throttle is in the fully closed position (reference position) even though the throttle is not fully closed, and the next trip (the next ignition switch is turned on). After that, it is forbidden to be controlled with the throttle opening being deviated, and it is possible to reliably prevent the exhaust gas performance from deteriorating and the output abnormality.

  In particular, the following configuration is listed as one for specifying the abnormality determining means. That is, the abnormality determining means determines that the throttle is fully closed when the time required for the engine speed to reach zero when the engine stops due to the ignition switch being turned off exceeds a predetermined threshold. ing.

  Because of this specific matter, it is determined that the throttle is fully closed when the time required for the engine speed to reach zero when the engine is stopped by turning off the ignition switch exceeds a predetermined threshold. Even if there is a fully closed abnormality where the throttle cannot be fully closed in the closed position, if the time required for the engine speed to reach zero is less than the predetermined threshold, the throttle is fully turned off when the engine is stopped by turning off the ignition switch. Engine vibration that increases due to the closed flow rate is also within the allowable range. As a result, it can be applied as long as the occurrence of a throttle fully closed abnormality is within an allowable range due to an error on the product, and the use frequency due to an error on the product can be increased.

  In short, by determining whether or not the throttle fully closed such as a diesel throttle is based on the engine speed reduction characteristics such as the time required for the engine speed to become zero when the engine is stopped by turning off the ignition switch, If a throttle full-close abnormality occurs when the engine is stopped due to the ignition switch being turned off, the throttle full-close abnormality is reliably detected due to the time required for the engine speed to reach zero. The temporary fully closed position of the throttle due to the fully closed abnormality is not erroneously recognized as the fully closed position of the throttle. This avoids erroneous learning of the fully closed position of the throttle, and can reliably prevent deterioration in exhaust gas performance and output abnormality after the next trip.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where this invention is applied to the common rail type | mold in-cylinder direct injection type multi-cylinder (for example, 4 cylinders) diesel engine mounted in the motor vehicle.

-Engine configuration description-
First, a schematic configuration of a diesel engine (hereinafter simply referred to as an engine) according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram of an engine 1 and its control system according to the present embodiment.

  An intake passage 4 (intake pipe) is connected to a combustion chamber 3 formed between a cylinder 1a and a piston 1b in the engine 1 via an intake valve 4a as an intake system. The intake passage 4 is provided with a diesel throttle 14 (throttle) for adjusting the amount of intake air introduced into the combustion chamber 3. Further, a throttle position sensor 141 for detecting the opening degree of the diesel throttle 14 is provided in the vicinity of the diesel throttle 14, and this throttle position sensor 141 is an electronic control device (hereinafter, “ ECU ”) 20).

  The diesel throttle 14 is driven to open and close by a drive mechanism 16. The drive mechanism 16 includes a step motor 18 as an electric motor and a gear group that drives and connects the step motor 18 and the diesel throttle 14. The step motor 18 is driven and controlled by the ECU 20.

  On the other hand, an exhaust passage 24 is connected to the combustion chamber 3 via an exhaust valve 24a as an exhaust system. An EGR (exhaust gas recirculation) passage 26 branches from the exhaust passage 24. The EGR passage 26 is connected to the downstream side of the diesel throttle 14 in the intake passage 4. The EGR passage 26 is provided with an EGR valve 30 that is opened and closed by an actuator 28 controlled by the ECU 20. By adjusting the intake air amount by the diesel throttle 14 and the EGR amount by the EGR valve 30, the ratio between the intake air amount introduced into the combustion chamber 3 and the EGR amount can be freely set. It is possible. As a result, the intake air amount and the EGR amount can be appropriately controlled over the entire operation region of the engine 1.

  Further, an exhaust purification device is provided in the exhaust passage 24 downstream of the EGR passage 26. The exhaust gas purification apparatus includes a DPF (Diesel Particulate Filter) 241 that collects PM (Particulate Matter) in exhaust gas, and a catalyst 242 such as an oxidation catalyst on the upstream side of the DPF 241.

  The engine 1 is provided with a plurality of cylinders (in this embodiment, four cylinders, but only one cylinder is shown) # 1, # 2, # 3, and # 4. The injectors 32 are arranged for the combustion chambers 3 to # 4. Fuel injection from the injector 32 to the cylinders # 1 to # 4 of the engine 1 is controlled by turning on / off the electromagnetic valve 32a for injection control.

  The injector 32 is connected to a common rail 34 as a pressure accumulating container common to each cylinder, and the fuel in the common rail 34 burns from the injector 32 while the injection control electromagnetic valve 32a is open (injector opening period). It is injected into the chamber 3. A relatively high pressure corresponding to the fuel injection pressure is accumulated in the common rail 34. In order to realize this pressure accumulation, the common rail 34 is connected to the discharge port 36 a of the supply pump 36 via the supply pipe 35. A check valve 37 is provided in the middle of the supply pipe 35. Due to the presence of the check valve 37, the supply of fuel from the supply pump 36 to the common rail 34 is allowed, and the backflow of fuel from the common rail 34 to the supply pump 36 is restricted.

  The supply pump 36 is connected to a fuel tank 38 via a suction port 36b, and a filter 39 is provided in the middle thereof. The supply pump 36 sucks fuel from the fuel tank 38 through the filter 39. At the same time, the supply pump 36 receives the rotational driving force from the crankshaft, which is the output shaft of the engine 1, and reciprocates the plunger to increase the fuel pressure to the required pressure. Supply.

  Further, a pressure control valve 40 is provided in the vicinity of the discharge port 36 a of the supply pump 36. The pressure control valve 40 is for controlling the fuel pressure (that is, injection pressure) discharged from the discharge port 36a to the common rail 34. When the pressure control valve 40 is opened, excess fuel that is not discharged from the discharge port 36 a is returned from the return port 36 c provided in the supply pump 36 to the fuel tank 38 via the return pipe (return flow path) 41. It is supposed to be.

  As described above, the fuel supply system of the engine 1 is configured with the fuel tank 38, the supply pump 36, the common rail 34, and the injector 32 as main components.

  The engine 1 is equipped with a turbocharger 42 that supercharges intake air using exhaust pressure. The turbocharger 42 includes a turbine 421 disposed downstream of the EGR passage 26 in the exhaust passage 24 and upstream of the exhaust purification device, and a compressor 422 disposed upstream of the diesel throttle 14 in the intake passage 4. The turbine 421 disposed in the exhaust passage 24 is rotated by the energy of the exhaust, and the compressor 422 disposed in the intake passage 4 is rotated accordingly. Then, the intake air is supercharged by the rotation of the compressor 422, and the supercharged air is forcibly sent into the combustion chambers 3 of the cylinders # 1 to # 4 of the engine 1. The turbocharger 42 is a variable nozzle turbocharger, and a variable nozzle vane mechanism 423 is provided on the turbine 421 side. By adjusting the opening of the variable nozzle vane mechanism 423, the supercharging pressure of the engine 1 can be increased. Can be adjusted. The opening degree of the variable nozzle vane mechanism 423 is adjusted by an actuator 424 such as a DC motor controlled by the ECU 20.

  Note that the crankshaft of the engine 1 is provided with a rotor that rotates in synchronization with the rotation of the crankshaft, and a convex signal formed on the outer peripheral surface of the rotor is detected and a pulse signal corresponding to the rotational speed is generated. There is provided a rotation speed sensor 44 (rotation speed detection means) comprising an electromagnetic pickup for output. The output of the rotation speed sensor 44 is taken into the ECU 20 as a signal that contributes to the calculation of the rotation speed of the engine 1.

  The ECU (Electronic Control Unit) 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a backup RAM, a timer, a counter, and the like, and an A / D (Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog / Analog An external input circuit including a digital converter and an external output circuit are connected by a bidirectional bus.

  The ECU 20 configured as described above inputs detection signals of various sensors via an external input circuit, and based on these signals, various controls relating to the operating state of the engine 1, such as basic control for fuel injection of the engine 1 and the like. Execute. Specifically, the ECU 20 includes accelerator opening information detected by the accelerator opening sensor 46 (accelerator pedal depression amount information) including the opening information of the diesel throttle 14 detected by the throttle position sensor 141 described above. ON / OFF information of IG (ignition) switch 48, ON / OFF information of starter switch 50, coolant temperature information detected by coolant temperature sensor 52 provided in water jacket 2a, shift position sensor provided in transmission Information such as shift position information detected by the vehicle 54, vehicle speed information detected by the signal of the vehicle speed sensor 56, and fuel pressure (injection pressure PC) information detected by the fuel pressure sensor 60 provided on the common rail 34 are also included. Captured, this It is configured to execute various controls relating to the operating state of the engine 1 based on Luo information.

  Next, the configuration of the throttle control device will be described with reference to FIG.

  In FIG. 2, the throttle control device includes a part of the ECU 20 or a controller or the like. The throttle position sensor 141 shown in FIG. 1 and an abnormality as abnormality determination means that is logically constructed in the ECU 20 shown in FIG. And a determination unit 201. In this throttle control device, the step motor 18 is controlled to open the diesel throttle 14 to the fully open position after the diesel throttle 14 is closed to the fully closed position when the engine 1 is stopped by turning off the IG switch 48.

  Here, the throttle position sensor 141 detects the actual opening of the diesel throttle 14 that is driven to open and close by the step motor 18 so as to adjust the amount of intake air into the cylinder 1a. As a result, the actual opening of the diesel throttle 14 is selectively detected at all times, including during normal operation, or at the time of abnormality where some abnormality is found. Further, the diesel throttle 14 is electrically connected to the ECU 20, and the detection result of the actual opening is transmitted to the ECU 20. The driving means for opening and closing the diesel throttle 14 may be an actuator other than a step motor.

  And the abnormality determination part 201 is provided with the timer and the calculating part. In this abnormality determination unit 201, foreign matter or the like bites into the diesel throttle 14 based on a decrease characteristic of the engine speed based on a signal detected by the speed sensor 44 when the engine 1 is stopped when the IG switch 48 is turned off. It is determined whether or not a fully closed abnormality has occurred. That is, the abnormality determination unit 201 determines whether or not the diesel throttle 14 is fully closed based on the time required for the engine speed measured by the timer to become zero when the engine 1 is stopped when the IG switch 48 is turned off. ing. Specifically, as shown in FIG. 3, the abnormality determination unit 201 is in a normal state where the foreign matter is not bitten and the diesel throttle A is in a normal state, and a minute foreign matter is bit within an allowable range or a slight product error. When the diesel throttle B within a certain allowable range is used, when the engine 1 is stopped due to the IG switch 48 being turned off, the engine speed decreasing characteristic that decreases with the passage of time is 3.6 from the time when the engine 1 is stopped. Focusing on the difference in the slope after 4.3 seconds (300 rpm), although the slope is the same in the vicinity of seconds to 4.3 seconds (700 rpm to 300 rpm), both diesel throttles A and B The extension line E from the straight line part (the part from 6 seconds to 4.3 seconds after the stop of the engine 1) where the inclination of the engine speed due to The base point P is set at a position where the engine speed becomes zero on the extension line E, and as shown in FIG. 4, X seconds (for example, 0.6 seconds) have elapsed from the base point P. The time point is set as a threshold value Q that matches the time required for the engine speed to become zero by the diesel throttle B within the allowable range. In short, when determining whether the diesel throttle 14 is fully closed by the abnormality determination unit 201, the slope of the engine speed decrease characteristic that decreases with the passage of time when the engine 1 is stopped when the IG switch 48 is turned off is measured by a timer. The engine speed from a base point P set at a position where the engine speed becomes zero on an extension line E from a straight line portion (a portion from 6 seconds to 4.3 seconds after the engine 1 is stopped) that is a substantially straight line. If the time required to reach zero is within the allowable threshold value Q after X seconds (eg, 0.6 seconds) have elapsed from the base point P, it is determined that “not fully closed”, while the threshold value Q is exceeded. In this case, it is determined that “it is a fully closed abnormality”. In this case, the difference in slope after 4.3 seconds (300 rpm) after the stop of the engine 1 of the diesel throttles A and B occurs because the pumping loss of the diesel throttle B is small. This is thought to be due to the increase.

  Next, the flow of operation processing related to the determination of the fully closed abnormality of the diesel throttle 14 by the abnormality determination unit 201 will be described with reference to the flowchart of FIG.

  First, after calculating the engine speed based on the signal detected by the rotational speed sensor 44 in step ST1 of the flowchart of FIG. 5, the actual opening of the diesel throttle 14 detected by the throttle position sensor 141 in step ST2. Is read. Next, in step ST3, various state quantities of the engine 1 are read. The various state quantities of the engine 1 are states in which the idle-up is operating depending on the operating state of the power steering, the air conditioner, and the like. In determining whether the diesel throttle 14 is fully closed by the abnormality determining unit 201, These situations are taken into account.

  Thereafter, in step ST4, it is determined whether or not the IG switch 48 is turned off. If the IG switch 48 is turned off, the process proceeds to step ST5.

  In this step ST5, an extension line E from a straight line portion (a portion from 6 seconds to 4.3 seconds after the engine 1 is stopped) in which the gradient of the engine speed decrease characteristic by the diesel throttle 14 becomes a substantially straight line. The base point P is set at a position where the engine speed is zero on the extension line E, and the time when X seconds (for example, 0.6 seconds) have passed from the base point P Set as the threshold Q within the range. The time required from the base point P until the engine speed actually becomes zero is measured by a timer.

  Then, in step ST6, it is determined whether or not the time T required from the base point P until the engine speed actually becomes zero is within X seconds (for example, 0.6 seconds), that is, within the threshold value Q (T ≦ Q). To do. If the determination in step ST6 is NO in which the time T required for the engine speed to actually become zero from the base point P exceeds the threshold Q (more than X seconds), the diesel throttle 14 is “fully closed”. An erroneous full-closed position learning that turns on the full-closed abnormality flag in step ST7 and learns that the diesel throttle 14 is in the fully-closed position even if it is not fully closed. In step ST8, a foreign matter removal operation such as repeating the forced opening and closing of the diesel throttle 14 a plurality of times is performed in consideration of the fully closed abnormality of the diesel throttle 14 due to the inclusion of foreign matter and the like.

  On the other hand, if the determination in step ST6 is YES when the time T required from the base point P until the engine speed actually becomes zero is within the threshold value Q (within X seconds), the diesel throttle 14 is “fully closed”. In step ST9, fully closed position learning of the diesel throttle 14 is performed.

  As described above, the engine speed becomes zero on the extended line E from the straight line portion where the slope of the descending characteristic of the engine speed that falls with the passage of time when the engine 1 is stopped by turning off the IG switch 48 is substantially a straight line. If the time T required for the engine speed to become zero from the base point P set at the position exceeds the threshold Q of the allowable range in which X seconds (for example, 0.6 seconds) have elapsed from the base point P, it is “abnormally closed”. It is determined. For this reason, if a fully closed abnormality has occurred when the engine 1 is stopped due to the IG switch 48 being turned off, the time T required for the engine speed to become zero increases, so that the fully closed abnormality of the diesel throttle 14 is increased. It is reliably detected, and the temporary fully closed position of the diesel throttle 14 due to the fully closed abnormality is not erroneously recognized as the fully closed position of the diesel throttle 14. As a result, an erroneous full-closed position learning that learns that the diesel throttle 14 is in the fully-closed position (reference position) even though the diesel throttle 14 is not fully closed is avoided. In this case, it is forbidden to be controlled in a state in which the throttle opening is deviated, and it is possible to reliably prevent a decrease in exhaust gas performance and an output abnormality.

  Moreover, if the time T required for the engine speed to become zero from the base point P when the engine 1 is stopped by turning off the IG switch 48 is within the allowable threshold value Q after X seconds from the base point P, the “fully closed abnormality” When the engine 1 is stopped due to the IG switch 48 being turned off, the vibration of the engine 1 that increases due to the fully closed flow rate of the diesel throttle 14 is also within the allowable range. Thereby, if the occurrence of the fully closed abnormality of the diesel throttle 14 is within the allowable range due to the error on the product, it can be applied, and the use frequency due to the error on the product can be increased.

  In the above embodiment, the diesel throttle 14 provided in the intake passage 4 of the diesel engine 1 has been described. However, the present invention is not limited to this and is provided in the intake passage of the gasoline engine. The present invention can be applied not only to a throttle valve (throttle) but also to a throttle in an intake passage of various internal combustion or external combustion engines such as a turbine engine and a jet engine.

  In the above embodiment, the time T required for the engine speed to become zero from the base point P on the extension line E when the engine 1 is stopped by turning off the IG switch 48 is in the range from the base point P to the threshold value Q (for example, 0). 6 seconds), it is determined whether the diesel throttle 14 is fully closed, but the time required for the engine speed to become zero from the base point P when the engine is stopped by turning off the IG switch is normal. Whether the diesel throttle is fully closed or not is determined based on whether or not the engine speed of the diesel throttle A is within the range (for example, 0.2 seconds) from the time K required until the engine speed reaches zero. Good.

1 is a schematic system diagram of an engine using a throttle control device according to an embodiment of the present invention. It is a block diagram of a throttle control apparatus. It is a characteristic view which shows the fall characteristic of an engine speed and throttle opening with respect to the time after the engine stop by turning off of IG switch. It is a characteristic view which shows the fall characteristic of the engine speed with respect to the time just before the engine stop by IG switch OFF. It is a flowchart figure which shows the flow of the operation process which concerns on the determination of the throttle full-close abnormality by the abnormality determination part.

Explanation of symbols

1 Engine 4 Intake passage (intake pipe)
14 Diesel throttle 18 Step motor (electric motor)
44 Rotational speed sensor (Rotational speed detection means)
48 IG switch (ignition switch)
20 ECU
201 Abnormality determination unit (abnormality determination means)
Q threshold

Claims (4)

A throttle control device that is provided in an intake pipe of an engine and controls a throttle that is opened and closed by an electric motor,
The throttle is controlled to be closed when the engine is stopped by turning off the ignition switch.
A rotational speed detecting means for detecting the rotational speed of the engine;
And an abnormality determining means for determining whether the throttle is fully closed based on a decrease characteristic of the engine speed detected by the engine speed detecting means when the engine is stopped by turning off the ignition switch. Throttle control device. The throttle control device according to claim 1,
A throttle control device characterized in that a diesel throttle provided in an intake pipe of a diesel engine is applied as the throttle. In the throttle control device according to claim 1 or 2,
The throttle control device characterized in that the time required for the engine speed to become zero when the engine is stopped by turning off the ignition switch is applied as the engine speed reduction characteristic. In the throttle control device according to claim 3,
The abnormality determining means determines that the throttle is fully closed when the time required for the engine speed to reach zero when the engine is stopped by turning off the ignition switch exceeds a predetermined threshold. A throttle control device characterized by that.

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