JP2009127549A - Engine control unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control unit capable of lowering the possibility of the erroneous determination of an abnormality in an air intake mechanism for adjusting the amount of air taken into an engine. <P>SOLUTION: An opening rate difference calculation part 1130 calculates an opening rate difference DIF that is an absolute value of the difference between a required throttle opening rate TH(D) and an actual throttle opening rate TH. A threshold calculation part 1140 calculates a determination threshold DET of the opening rate difference DIF based on the engine rotational number NE and the required throttle opening rate TH(D). The variation of the throttle opening rate to obtain the predetermined torque variation becomes larger in the higher torque range of the engine and becomes smaller in the lower torque range of the engine. The determination part 1150 determines that the intake mechanism (intake system) including a throttle valve 102 is abnormal when the opening differential rate DIF is larger than the determination threshold DET. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly to a technique for calculating a target torque of an engine and adjusting an air amount taken into the engine based on the target torque.

2. Description of the Related Art Conventionally, a technique has been proposed in which a target torque of an engine is calculated and a throttle opening is controlled so as to realize the target torque, thereby adjusting the amount of air taken into the engine. Japanese Patent Laid-Open No. 2-147439 (Patent Document 1) describes an automatic travel control device for a vehicle that sets a target torque based on a target vehicle speed and a target acceleration, and the throttle opening of an engine according to the target torque. The control part which can set is provided. The vehicle automatic travel control apparatus further includes a throttle valve rotating unit that can drive a throttle valve through a throttle actuator in accordance with a throttle opening set by the control unit, and a throttle that detects an actual opening of the throttle valve. An opening detection unit, a throttle actuator abnormality determining means capable of determining whether or not the operation of the throttle actuator is abnormal based on the set throttle opening and the actual opening of the throttle valve; Is provided. If the throttle actuator abnormality determining means determines that there is a difference of a certain amount or more between the target throttle opening and the actual opening, it determines that the operation of the throttle actuator is abnormal.
Japanese Patent Laid-Open No. 2-147439

  By the way, due to the characteristics of the engine, in the high torque region, even if the throttle opening is greatly changed, the amount of change in the engine output torque is small. In the high torque region, the amount of change in torque with respect to the engine speed is small.

  The abnormality determination method described in Japanese Patent Laid-Open No. 2-147439 is a method for determining that the throttle actuator is abnormal when the difference between the target throttle opening and the actual opening exceeds a certain amount. However, according to this method, when the control to bring the actual torque closer to the target torque is executed in the high torque region, the required throttle opening that is predetermined as the throttle opening for obtaining the target torque and the actual torque are obtained. There is a high possibility that the difference from the actual throttle opening at this time exceeds the reference value.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the possibility of an error occurring in the abnormality determination of the intake mechanism for adjusting the amount of air taken into the engine. It is to provide an engine control device capable of performing the above.

  In summary, the present invention is an engine control device that is mounted on a vehicle and whose intake air amount is adjusted by an intake mechanism including a throttle valve. The control device includes: a torque setting unit that sets a target torque of the vehicle based on a driving state of the vehicle; a first calculation unit that calculates a target opening of the throttle valve based on the target torque; The absolute value of the difference between the adjustment unit that adjusts the actual opening so that the opening becomes the target opening, the detection unit that detects the actual opening, the actual opening detected by the detection unit, and the target opening A second calculation unit that calculates the determination target value, a third calculation unit that calculates a determination threshold value of the determination target value based on the target opening and the engine speed of the engine, and the determination target value And a determination unit that determines that the intake mechanism is abnormal when the determination threshold is exceeded.

  Preferably, the third calculation unit calculates the determination threshold according to a predetermined relationship such that the determination threshold increases as the engine speed increases.

  Preferably, the third calculation unit makes a determination according to a predetermined relationship such that the determination threshold value increases as the target opening degree increases when the target opening degree is changed while the engine speed is constant. Calculate the threshold.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to make low possibility that an error will arise in the abnormality determination of the intake mechanism which adjusts the air quantity suck | inhaled by an engine.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  With reference to FIG. 1, a power train of a vehicle including a control device according to the present embodiment will be described. In the present embodiment, the automatic transmission is described as an automatic transmission having a gear-type transmission mechanism that includes a torque converter as a fluid coupling. Note that the present invention is not limited to an automatic transmission having a gear-type transmission mechanism, and may be a continuously variable transmission such as a belt type. The gear-type speed change mechanism may be constituted by a planetary gear or may be constituted by a constantly meshing gear.

  As shown in FIG. 1, the vehicle power train includes an engine 100, a torque converter 200, an automatic transmission 300, and an ECU (Electronic Control Unit) 1000.

  The amount of air taken into engine 100 is adjusted by throttle valve 102. In addition, a variable intake system is provided to effectively use the pulsation effect caused by pressure fluctuations generated in the intake pipe and to increase the torque of engine 100.

  In the variable intake system, an ACIS (Acoustic Control Induction System) valve 104 switches the effective intake pipe length in two stages in accordance with the period of the pulsating flow. The opening and closing of the ACIS valve 104 is controlled according to the throttle opening and the target torque.

  For example, when the throttle opening or the target torque is large and the load is high, the ACIS valve 104 is controlled so that the effective intake pipe length becomes long. On the other hand, when the throttle opening or the target torque is small and the load is low, the ACIS valve 104 is controlled so that the effective intake pipe length is shortened.

  Further, the amount of air charged into the cylinder of engine 100, that is, the output torque of engine 100, is adjusted by changing the opening / closing timing of intake valve 108 and exhaust valve 110 by variable valve timing mechanism 106. The opening / closing timing of the intake valve 108 and the exhaust valve 110 is controlled according to the throttle opening.

  For example, the cylinder is filled by adjusting the overlap amount of the intake valve 108 and the exhaust valve 110 according to the throttle opening, that is, depending on the load, or adjusting the closing timing of the intake valve 108. The amount of air and internal EGR (Engine Gas Recirculation) are adjusted, and the output torque of the engine 100 is finely controlled.

  The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft rotational speed NE (engine rotational speed NE) of engine 100 detected by the engine rotational speed sensor and input shaft rotational speed (pump rotational speed) of torque converter 200 are the same.

  The torque converter 200 has a lock-up clutch that directly connects the input shaft and the output shaft, a pump impeller on the input shaft side, a turbine impeller on the output shaft side, and a one-way clutch, and exhibits a torque amplification function. It consists of a stator. Torque converter 200 and automatic transmission 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by a turbine rotational speed sensor. The output shaft rotational speed NOUT of the automatic transmission 300 is detected by an output shaft rotational speed sensor.

  Such an automatic transmission 300 includes a plurality of friction elements such as clutches and brakes. Based on a predetermined operation table, clutch elements (for example, clutches C1 to C4) that are friction elements, brake elements (for example, brakes B1 to B4), and one-way clutch elements (for example, one-way clutches F0 to F3) are required. The hydraulic circuit is controlled so as to be engaged and released corresponding to each gear stage. Shift positions (shift positions) of the automatic transmission 300 include a parking (P) position, a reverse travel (R) position, a neutral (N), and a forward travel (D) position.

  The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100 and an ECT (Electronic Controlled Transmission) _ECU 1020 that controls the automatic transmission 300.

  In the present embodiment, ECU 1000 calculates a required torque as a target torque of engine 100 based on the engine speed, the accelerator opening, and the like, and controls throttle valve 102 of engine 100 to realize this required torque. To do.

  Based on the required torque calculated by the ECU 1000, the engine ECU 1010 of the ECU 1000 calculates the required throttle opening as the target opening of the throttle valve 102, and controls the throttle valve 102 so that the throttle opening becomes the required throttle opening. .

  Engine ECU 1010 further receives a signal indicating the actual opening (actual throttle opening) of throttle valve 102. When the difference between the required throttle opening and the actual throttle opening exceeds the determination threshold, engine ECU 1010 determines that an abnormality has occurred in the intake system and executes an abnormality process.

  ECT_ECU 1020 receives a signal representing output shaft rotational speed NOUT detected by the output shaft rotational speed sensor. ECT_ECU 1020 receives an engine speed signal representing engine speed NE detected by the engine speed sensor from engine ECU 1010.

  These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of torque converter 200, the output shaft of torque converter 200, and the output shaft of automatic transmission 300. These rotational speed sensors are sensors that can detect slight rotations of the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the automatic transmission 300. This is a sensor using a magnetoresistive element.

  ECT_ECU 1020 outputs a lockup clutch control signal for torque converter 200. Based on this lockup clutch control signal, the engagement pressure of the lockup clutch is controlled. The ECT_ECU 1020 outputs a solenoid control signal to the automatic transmission 300. Based on this solenoid control signal, the linear solenoid valve, the on-off solenoid valve, etc. of the hydraulic circuit of the automatic transmission 300 are controlled, and friction is established so as to constitute a predetermined speed gear stage (for example, first speed to fifth speed). The engagement element is controlled to be engaged and released.

  The ECT_ECU 1020 is supplied with a signal representing the opening (accelerator opening) of the accelerator pedal 2102 operated by the driver from the accelerator opening sensor 2100 and a signal representing the vehicle speed from the vehicle speed sensor 2200. The ECT_ECU 1020 detects the change rate of the accelerator opening based on the signal transmitted from the accelerator opening sensor 2100. ECU 1000 has a memory in which various data and programs are stored. In addition, instead of the accelerator opening, the depression force of the accelerator pedal 2102 may be detected. Similarly, instead of the change rate of the accelerator opening, the change rate of the depression force of the accelerator pedal 2102 may be detected. A signal representing the accelerator opening is also input to engine ECU 1010.

  Engine ECU 1010 and ECT_ECU 1020 transmit and receive signals to and from each other. In the present embodiment, engine ECU 1010 calculates an actual net engine torque used for controlling automatic transmission 300 and transmits it to ECT_ECU 1020. The ECT_ECU 1020 controls the automatic transmission 300 using the actual net engine torque transmitted from the engine ECU 1010.

  FIG. 2 is a functional block diagram of the engine control apparatus according to the embodiment of the present invention. Referring to FIG. 2, engine ECU 1010 includes a required torque calculation unit 1110, a required throttle opening calculation unit 1120, an opening difference calculation unit 1130, a threshold value calculation unit 1140, a determination unit 1150, and an abnormal time. And a processing unit 1160.

  The opening degree of the throttle valve 102 is controlled by the opening degree control unit 120. The opening degree control unit 120 includes a drive unit 122 and an opening degree detection unit 124.

  Requested torque calculation unit 1110 receives a signal indicating accelerator opening degree ACC from accelerator opening sensor 2100 and a signal indicating engine speed NE from engine speed sensor 130. The accelerator opening ACC and the engine speed NE are included in the information related to the driving situation of the vehicle. Requested torque calculation unit 1110 calculates required torque of engine 100 (target torque of engine 100) T (D) based on these signals. It should be noted that the required torque of engine 100 is calculated based on a map obtained in advance by experiments or the like.

  The required throttle opening calculation unit 1120 calculates a required throttle opening TH (D) as a target opening based on the required torque T (D). The required throttle opening TH (D) is calculated using a map obtained in advance by experiments or the like.

  The driving unit 122 receives a signal indicating the required throttle opening TH (D) from the required throttle opening calculating unit 1120 and controls the throttle valve 102 so that the actual throttle opening becomes the required throttle opening TH (D). Control. The opening detection unit 124 detects the actual throttle opening of the throttle valve 102 and transmits the detected actual throttle opening TH to the opening difference calculation unit 1130.

  The opening difference calculation unit 1130 calculates an opening difference DIF that is an absolute value of a difference between the required throttle opening TH (D) and the actual throttle opening TH.

  The threshold calculation unit 1140 calculates a determination threshold DET for the opening difference DIF based on the engine speed NE and the required throttle opening TH (D).

  The determination unit 1150 determines whether or not the opening degree difference DIF is greater than the determination threshold value DET. When the opening degree difference DIF is larger than the determination threshold value DET, the determination unit 1150 determines that the intake mechanism (intake system) including the throttle valve 102 is abnormal. On the other hand, when opening degree difference DIF is equal to or smaller than determination threshold value DET, determination unit 1150 determines that the intake mechanism (intake system) is normal. If the determination unit 1150 determines that the intake mechanism (intake system) is abnormal, the determination unit 1150 outputs the determination result to the abnormality processing unit 1160.

  The abnormality in the intake system is, for example, an abnormality in the throttle valve. However, the abnormality in the intake system is not limited to the abnormality in the throttle valve, and may include, for example, an abnormality in the ACIS valve and / or an abnormality in the opening / closing timing of the intake valve 108.

  The abnormal time processing unit 1160 receives the determination result from the determination unit 1150 and executes the abnormal time processing. An example of processing at the time of abnormality is shown below. For example, the abnormal time processing unit 1160 instructs the required throttle opening degree calculation unit 1120 to temporarily stop the calculation of the required throttle opening degree TH (D). Further, for example, the abnormality time processing unit 1160 sends an instruction for stopping the opening / closing of the throttle valve 102 to the driving unit 122.

  In the present embodiment, the engine control device includes an engine ECU 1010 and an opening degree control unit 120. Next, the processing of the engine control apparatus according to the present embodiment will be described in more detail with reference to FIG. The process shown in FIG. 5 is called and executed from the main routine at regular intervals, for example.

  With reference to FIGS. 5 and 2, when the process is started, in step S <b> 1, required torque calculation unit 1110 obtains engine speed NE and accelerator opening ACC. Then, the required torque calculator 1110 calculates the required torque T (D) based on the acquired engine speed NE and accelerator opening ACC.

  In step S2, the required throttle opening degree calculation unit 1120 calculates the required throttle opening degree TH (D) based on the required torque T (D).

  In step S3, the threshold value calculation unit 1140 calculates a determination threshold value DET based on the required throttle opening TH (D) and the engine speed NE.

  FIG. 3 is a graph showing the relationship between the engine speed and the engine output torque. As shown in FIG. 3, when the throttle opening is the same, the torque change amount decreases as the engine speed NE increases. Further, the amount of change in the throttle opening for obtaining a certain amount of torque change increases as the output torque increases.

  For this reason, the threshold value calculation unit 1140 stores the map shown in FIG. As shown in FIG. 4, the map defines a correspondence relationship of the determination threshold value with respect to the engine speed, with the required throttle opening TH (D) as a parameter. FIG. 4 typically shows a case where the required throttle opening TH (D) is relatively large (for example, TH (D) = 80%) and a case where the required throttle opening TH (D) is relatively small (for example, The correspondence relationship between the engine speed and the determination threshold value in each case of TH (D) = 5%) is shown.

  The map shown in FIG. 4 is obtained in advance by experiments or the like. Further, the map shown in FIG. 4 is an example, and the present invention is not limited to this.

  The threshold value calculation unit 1140 calculates a determination threshold value DET from the map shown in FIG. 4, the engine speed NE, and the required throttle opening TH (D).

  When the process of step S3 ends, the process of step S4 is executed. In step S4, the opening degree detection unit 124 detects the actual throttle opening degree TH of the throttle valve 102. The opening degree difference calculation unit 1130 acquires the actual throttle opening degree TH from the opening degree detection unit 124.

  In step S <b> 5, the opening degree difference calculation unit 1130 acquires the required throttle opening degree TH (D) from the required throttle opening degree calculation unit 1120 and acquires the determination threshold value DET from the determination threshold value calculation unit 1140. Then, the opening degree difference calculating unit 1130 calculates an opening degree difference DIF that is an absolute value of the difference between the requested throttle opening degree TH (D) and the actual throttle opening degree TH, and the opening degree difference DIF is determined from the determination threshold value DET. It is determined whether it is too large.

  If opening degree difference DIF is equal to or smaller than determination threshold value DET (NO in step S5), the entire process is returned to the main routine. On the other hand, when opening degree difference DIF is larger than determination threshold value DET (YES in step S5), determination unit 1150 determines that the intake mechanism (intake system) including throttle valve 102 is abnormal, and the determination The result is output to the abnormal time processing unit 1160. The abnormal time processing unit 1160 executes abnormal time processing according to the determination result of the determination unit 1150 (step S6). When the process of step S6 ends, the entire process is returned to the main routine.

  Referring to FIG. 3 again, the amount of change in the throttle opening for obtaining a certain amount of torque change increases in the high torque region, but decreases in the low torque region. For this reason, when the determination threshold value is set constant regardless of the torque region, the following state may occur.

  First, in the high torque region, the amount of change in the throttle opening for obtaining a predetermined amount of torque change increases. For example, in order to bring the actual torque closer to the required torque, it is necessary to greatly change the actual throttle opening. For this reason, there is a high possibility that the opening degree difference DIF exceeds the determination threshold even if the intake system is normal.

  On the other hand, when a predetermined determination threshold is determined from the relationship between the amount of change in throttle opening and the amount of change in torque in the high torque region, the determination threshold is likely to be a large value. In this case, there is a possibility that the abnormality of the intake system cannot be determined in the low torque region. For example, it is assumed that a certain required throttle opening (for example, 10%) is calculated from the required torque and the engine speed NE, but the actual throttle opening becomes 0% due to an abnormality in the intake system. However, if the opening degree difference DIF (in this case, 10%) is equal to or less than the determination threshold value, it is determined that the intake system is normal. That is, erroneous determination occurs.

  In the present embodiment, the determination threshold value DET is calculated according to the map of FIG. In the map of FIG. 4, the determination threshold value increases as the engine speed increases, regardless of the required throttle opening TH (D). That is, the determination threshold value DET increases in the high torque region, and the determination threshold value DET decreases in the low torque region.

  As a result, since the actual torque is brought close to the required torque in the high torque region, the possibility of erroneous determination that an abnormality has occurred in the intake system can be reduced even if the actual throttle opening greatly changes. On the other hand, in the low torque region, when the opening degree difference DIF becomes large due to an abnormality in the intake system, the abnormality can be detected. Therefore, according to the present embodiment, it is possible to reduce the possibility of an error in the abnormality determination of the intake system.

  Further, the map of FIG. 4 shows that the determination threshold value increases as the required throttle opening increases at the same engine speed. As shown in FIG. 3, when the engine speed is the same, the torque variation with respect to the engine speed decreases as the throttle opening increases. Therefore, since the determination threshold value is increased particularly when the engine speed is high and the throttle opening is high, it is possible to reduce the possibility of an error in the intake system abnormality determination.

  Thus, according to the present embodiment, when the amount of torque change is small, that is, when the engine speed is high or when the required throttle opening is large, the determination threshold value is increased. When the engine speed is low and the required throttle opening is small, the determination threshold value is decreased. As a result, it is possible to reduce the possibility of an error occurring in the abnormality determination of the adjustment mechanism (intake system) that adjusts the amount of air taken into the engine.

  Furthermore, according to the present embodiment, it is possible to realize the throttle opening degree according to the driver's request by reducing the possibility of such an erroneous determination, so that the driver's request is met. Output torque can be realized.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a control block diagram which shows the vehicle carrying the engine control apparatus which concerns on embodiment of this invention. It is a functional block diagram of the control apparatus of the engine which concerns on embodiment of this invention. It is a figure which shows the relationship between an engine speed and the output torque of an engine. It is a figure which shows an example of the map memorize | stored in the threshold value calculation part 1140. It is a flowchart for demonstrating the abnormality determination process of the throttle opening which the control apparatus of the engine which concerns on the form of this invention performs.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Engine, 102 Throttle valve, 104 ACIS valve, 106 Variable valve timing mechanism, 108 Intake valve, 110 Exhaust valve, 120 Opening control part, 122 Driving part, 124 Opening detection part, 130 Engine speed sensor, 200 Torque converter , 300 automatic transmission, 1000 ECU, 1010 engine ECU, 1020 ECT_ECU, 1110 required torque calculation unit, 1120 required throttle opening calculation unit, 1130 opening difference calculation unit, 1140 threshold value calculation unit, 1150 determination unit, 1160 abnormality Time processing unit, 2100 accelerator opening sensor, 2102 accelerator pedal, 2200 vehicle speed sensor.

Claims (3)

An engine control device mounted on a vehicle and having an intake air amount adjusted by an intake mechanism including a throttle valve,
A torque setting unit for setting a target torque of the vehicle based on a driving state of the vehicle;
A first calculator that calculates a target opening of the throttle valve based on the target torque;
An adjusting unit that adjusts the actual opening so that the actual opening of the throttle valve becomes the target opening;
A detection unit for detecting the actual opening;
A second calculation unit that calculates an absolute value of a difference between the actual opening detected by the detection unit and the target opening as a determination target value;
A third calculation unit that calculates a determination threshold value of the determination target value based on the target opening and the engine speed of the engine;
An engine control device comprising: a determination unit that determines that the intake mechanism is abnormal when the determination target value exceeds the determination threshold value.   The engine control according to claim 1, wherein the third calculation unit calculates the determination threshold according to a predetermined relationship such that the determination threshold increases as the engine speed increases. apparatus.   In the case where the target opening is changed with the engine speed being constant, the third calculation unit is configured according to a predetermined relationship such that the determination threshold value increases as the target opening increases. The engine control device according to claim 1, wherein the determination threshold value is calculated.

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