Engine control unit

Abstract

To enhance stability of a throttle opening and improve control accuracy of engine torque in an engine control device.SOLUTION: An engine control device 10 includes a pressure ratio equivalent value calculation section 11, a sensor pressure ratio calculation section 12, a correction pressure ratio calculation section 13 and a control section 20. The pressure ratio equivalent value calculation section 11 calculates a pressure ratio equivalent value A that is a ratio of a target torque equivalent value to a maximum torque equivalent value of an engine 1. The sensor pressure ratio calculation section 12 calculates a sensor pressure ratio B that is a ratio of downstream pressure to upstream pressure of a throttle valve 3. The correction pressure ratio calculation section 13 calculates a correction pressure ratio C on the basis of the pressure ratio equivalent value A and the sensor pressure ratio B when the pressure ratio equivalent value A or the sensor pressure ratio B is a predetermined value D or greater. The control section 20 controls an opening of the throttle valve 3 on the basis of the correction pressure ratio C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an engine control device for controlling the opening of a throttle valve. [Background technology]

[0002] Conventionally, in torque-based control, which controls the operating state of an engine based on torque, a method for controlling the opening of a throttle valve based on a pressure ratio equivalent value and a sensor pressure ratio has been known. The pressure ratio equivalent value is, for example, the ratio of a target torque to the maximum torque of the engine, and the sensor pressure ratio is, for example, the ratio of a downstream pressure to an upstream pressure of the throttle valve actually measured by a sensor. The flow velocity of intake air passing through the throttle valve is estimated based on the pressure ratio equivalent value and the sensor pressure ratio. The opening area of ​​the throttle valve is calculated from this flow velocity and a target flow rate of intake air, and the throttle opening is controlled based on the opening area (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5598374 Summary of the Invention [Problem to be solved by the invention]

[0004] When the sensor pressure ratio is relatively high, flow velocity changes significantly with even small fluctuations in the sensor pressure ratio. This reduces the stability of the throttle opening and reduces the accuracy of engine torque control. For example, if the sensor pressure ratio decreases slightly when the throttle is fully open, the estimated intake air flow velocity increases significantly, causing the target throttle opening to decrease. If the actual throttle opening is narrowed in response, the sensor pressure ratio decreases further, making it more likely that control will proceed in the direction of closing the throttle opening. In other words, a slight decrease in the sensor pressure ratio can trigger a further decrease in the sensor pressure ratio, ultimately resulting in a severe throttle narrowing.

[0005] Conversely, if the sensor pressure ratio increases slightly when the throttle is near full open, the estimated intake air flow rate decreases significantly, causing the target throttle opening to increase. When the actual throttle opening increases accordingly, the sensor pressure ratio increases further, causing control to proceed in the direction of full throttle opening. In other words, a slight increase in the sensor pressure ratio can trigger a further increase in the sensor pressure ratio, ultimately resulting in the throttle being opened to a large degree.

[0006] One of the objects of the present invention, which was devised in light of the above-mentioned problems, is to provide an engine control device that can increase the stability of the throttle opening and improve the control accuracy of the engine torque. However, in addition to this object, another object of the present invention is to achieve the effects derived from the configurations shown in the "Description of Embodiments" below, which cannot be obtained by conventional techniques. [Means for solving the problem]

[0007] The disclosed engine control device can be realized as the following disclosed aspects or application examples, and solves at least some of the above-mentioned problems. The disclosed engine control device includes a pressure ratio equivalent value calculation unit that calculates a pressure ratio equivalent value, which is the ratio of a target torque equivalent value of the engine to a maximum torque equivalent value of the engine; a sensor pressure ratio calculation unit that calculates a sensor pressure ratio, which is the ratio of a downstream pressure to an upstream pressure of a throttle valve; a corrected pressure ratio calculation unit that calculates a corrected pressure ratio based on the pressure ratio equivalent value and the sensor pressure ratio when the pressure ratio equivalent value or the sensor pressure ratio is equal to or greater than a predetermined value; and a control unit that controls the opening of the throttle valve based on the corrected pressure ratio. When the pressure ratio equivalent value becomes equal to or greater than the predetermined value before the sensor pressure ratio, the control unit controls the opening degree of the throttle valve using the larger of the sensor pressure ratio and the corrected pressure ratio. [Effects of the Invention]

[0008] According to the disclosed engine control device, when the pressure ratio equivalent value or the sensor pressure ratio is equal to or greater than a predetermined value, a corrected pressure ratio is calculated, and the throttle valve opening is controlled based on the corrected pressure ratio, thereby suppressing fluctuations in the throttle opening in response to minute fluctuations in the sensor pressure ratio, thereby increasing the stability of the throttle opening and improving the control accuracy of the engine torque. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a block diagram illustrating the configuration of an engine and an engine control device. [Figure 2] 4 is a graph showing the relationship between the flow velocity of air flowing through a throttle valve and the pressure ratio. [Figure 3] FIG. 2 is a block diagram for explaining the control contents of the engine control device. [Figure 4] 10A and 10B are graphs for explaining changes in the corrected pressure ratio, where (A) is a graph when the pressure ratio equivalent value becomes equal to or greater than a predetermined value before the sensor pressure ratio, and (B) is a graph when the sensor pressure ratio becomes equal to or greater than the predetermined value before the pressure ratio equivalent value. DETAILED DESCRIPTION OF THE INVENTION

[0010] The disclosed engine control device is applicable to various engines in which a throttle valve is installed in the intake passage. This engine control device is applicable to, for example, automobile engines, marine engines, industrial engines, etc. In the following embodiment, an engine control device applied to an engine mounted on a vehicle is exemplified. Note that types of engines to which the engine control device is applicable include gasoline engines and diesel engines. In the following embodiment, the device configuration and the like will be described assuming a gasoline engine. [Example]

[0011] [1. Configuration] An engine control device 10 according to an embodiment is applied to an on-vehicle engine 1 shown in Fig. 1. Here, one of the multiple cylinders provided in the multi-cylinder engine 1 is illustrated. An intake manifold 2 is attached upstream of the cylinder in the intake flow. The intake manifold 2 is formed in a branched shape so that the intake flow can be introduced to each of the multiple cylinders.

[0012] A throttle valve 3 for controlling the amount of intake air introduced into the cylinders of the engine 1 is installed in the intake passage upstream of the intake manifold 2 in the intake air flow. The flow rate of air passing through the throttle valve 3 and flowing toward the intake manifold 2 is adjusted according to the opening degree (throttle opening degree) of the throttle valve 3. The throttle opening degree is electrically controlled by the engine control device 10.

[0013] An intake manifold pressure sensor 4 is provided in the surge tank of the intake manifold 2. The intake manifold pressure sensor 4 is a sensor that detects the intake manifold pressure (pressure inside the surge tank), which is the pressure downstream of the throttle valve 3. In addition, an upstream pressure sensor 5, an air flow sensor 6, and an intake air temperature sensor 7 are provided in the intake passage upstream of the throttle valve 3. The upstream pressure sensor 5 is a sensor that detects the pressure upstream of the throttle valve 3. The air flow sensor 6 is a sensor that detects the intake air flow rate, and the intake air temperature sensor 7 is a sensor that detects the intake air temperature.

[0014] An engine rotation speed sensor 8 that detects the engine rotation speed (number of engine rotations per unit time) is provided near the crankshaft of the engine 1. In addition, an accelerator position sensor 9 that detects the amount of depression of the accelerator pedal (accelerator position) is provided at an arbitrary position on the vehicle. The accelerator position is a parameter that corresponds to the driver's request for acceleration and intention to start, and is a parameter that represents the load on the engine 1 (output request to the engine 1).

[0015] The engine control device 10 is one of the electronic control devices (ECU, Electronic Control Unit) mounted on a vehicle. The engine control device 10 incorporates a processor (central processing unit), memory (main memory), storage device, interface device, etc. (not shown), which are connected to each other so that they can communicate with each other. The contents of the control executed by the engine control device 10 are recorded and saved in the memory or storage device as firmware or an application program. When a program is executed, the contents of the program are expanded and arithmetic processing is performed by the processor.

[0016] The engine control device 10 of this embodiment performs torque-based control based on the magnitude of the torque required of the engine 1. Specific control targets of the engine control device 10 include the fuel injection amount, the timing of fuel injection (fuel injection timing), the timing of ignition by the spark plug (ignition timing), and the throttle opening. In this embodiment, the focus will be on engine torque control (intake amount control) by adjusting the throttle opening, and its function will be explained.

[0017] The throttle opening is controlled based on a target flow rate of intake air, which is set according to the target torque of the engine 1, and a pressure ratio, which is the ratio of the downstream pressure to the upstream pressure of the throttle valve 3. The target torque is calculated based on the accelerator opening and engine speed at that time. The target flow rate is a target value for the mass flow rate of air passing through the throttle valve 3, and is calculated, for example, based on a control map or formula that defines the relationship between the target torque and the target flow rate.

[0018] The value of the pressure ratio may be determined, for example, by actually measuring the upstream and downstream pressures of the throttle valve 3 and then dividing the downstream pressure value by the upstream pressure. Alternatively, the upstream pressure and downstream pressure may be estimated based on atmospheric pressure and the operating state of the engine 1, and the value may be determined using the actual measured values ​​or the estimated values. Here, the value obtained by dividing the intake manifold pressure detected by the intake manifold pressure sensor 4 by the upstream pressure detected by the upstream pressure sensor 5 is defined as the sensor pressure ratio. In this embodiment, it is assumed that the sensor pressure ratio is used as the above-mentioned pressure ratio, but it is also possible to use a pressure ratio other than the sensor pressure ratio (for example, a pressure ratio calculated using an estimated value instead of the actual measured value obtained by the sensor).

[0019] FIG. 2 is a graph showing the relationship between the pressure ratio and the flow velocity of air passing through the throttle valve 3. The flow velocity decreases as the pressure ratio increases. On the other hand, when the pressure ratio is smaller than the critical pressure ratio P0, the flow velocity remains constant. Based on this characteristic, the graph in FIG. 2 defines the pressure ratio as a range between 0 and 1, with the flow velocity being 0 when the pressure ratio is 1. The graph also shows a relationship between the pressure ratio and the flow velocity such that the flow velocity increases as the pressure ratio decreases, and when the pressure ratio is less than the critical pressure ratio P0, the flow velocity reaches an upper limit value V0 corresponding to the speed of sound. The range of pressure ratios smaller than the critical pressure ratio P0 is called the critical region, and the range of pressure ratios equal to or greater than the critical pressure ratio P0 is called the non-critical region.

[0020] In the non-critical region in Figure 2, the gradient of the decrease in flow velocity with respect to the pressure ratio increases as the pressure ratio approaches 1. Therefore, for example, if the pressure ratio fluctuates slightly due to a slight change in the pressure value obtained by the intake manifold pressure sensor 4 or the upstream pressure sensor 5, the flow velocity will change significantly. As a result, there is a concern that the throttle opening will fluctuate significantly, reducing the control accuracy of the engine torque.

[0021] Therefore, the engine control device 10 of this embodiment performs two types of control to improve the control accuracy of the engine torque in controlling the throttle opening. The first type of control is based on a flow velocity calculated from the pressure ratio (or a value equivalent to the pressure ratio) and a target flow rate. The first type of control is performed when the pressure ratio is relatively low (other than when the pressure ratio is relatively high, as described below). The second type of control is performed when the pressure ratio is relatively high, by calculating a corrected pressure ratio based on the pressure ratio and a value equivalent to the pressure ratio, and using the corrected flow velocity calculated based on this, thereby improving the control accuracy of the engine torque. The second type of control is performed when the pressure ratio is relatively high. These two types of control are described in detail below.

[0022] [2. Engine control device] The engine control device 10 calculates a target value for the torque required of the engine 1 that is achieved by adjusting the amount of intake air as the target torque, and controls the throttle opening so that the amount of air required to generate the target torque passes through the throttle valve 3. An intake manifold pressure sensor 4, an upstream pressure sensor 5, an airflow sensor 6, an intake air temperature sensor 7, an engine rotation speed sensor 8, an accelerator position sensor 9, etc. are connected to the input side of the engine control device 10, and the throttle valve 3 is connected to the output side.

[0023] 1, the engine control device 10 is provided with a pressure ratio equivalent value calculation unit 11, a sensor pressure ratio calculation unit 12, a corrected pressure ratio calculation unit 13, and a control unit 20. These elements are shown by conveniently classifying the functions of the engine control device 10, and each element may be written as an independent program, or may be written as a composite program combining these functions.

[0024] The pressure ratio equivalent value calculation unit 11 calculates a pressure ratio equivalent value A, which is the ratio of a target torque equivalent value of the engine 1 to a maximum torque equivalent value of the engine 1. The maximum torque equivalent value means the maximum torque that can be generated by the engine 1, or a physical quantity corresponding to this maximum torque (for example, the maximum charging efficiency or the corresponding maximum mean effective pressure). The maximum torque is the torque generated when the intake air amount is maximum in the operating state of the engine 1 at that time (the torque generated when the throttle valve 3 is fully opened). Furthermore, the maximum charging efficiency is a value obtained by converting the maximum torque into charging efficiency (air amount), and the maximum mean effective pressure is a value obtained by converting the maximum torque into mean effective pressure (in-cylinder pressure).

[0025] The target torque equivalent value means a target torque set based on an output request to the engine 1, or a physical quantity corresponding to this target torque (for example, a target filling efficiency or a corresponding target mean effective pressure). The target torque is calculated based on, for example, the engine rotation speed and the accelerator opening. The target filling efficiency is a value obtained by converting the target torque into a filling efficiency (air amount), and the target mean effective pressure is a value obtained by converting the target torque into a mean effective pressure (in-cylinder pressure).

[0026] The sensor pressure ratio calculation unit 12 calculates a sensor pressure ratio B as the pressure ratio (ratio of downstream pressure to upstream pressure) of the throttle valve 3. In this embodiment, the sensor pressure ratio B is calculated by dividing the intake manifold pressure by the upstream pressure based on the upstream pressure detected by the upstream pressure sensor 5 and the intake manifold pressure detected by the intake manifold pressure sensor 4. Note that the sensor pressure ratio B may be calculated based on a control map or a formula that takes into account the influence of pressure loss near the throttle valve 3 and in the intake passage, in addition to the upstream pressure and the intake manifold pressure.

[0027] The corrected pressure ratio calculation unit 13 calculates a corrected pressure ratio C based on the pressure ratio equivalent value A and the sensor pressure ratio B when the pressure ratio equivalent value A or the sensor pressure ratio B is equal to or greater than a predetermined value D. The predetermined value D is a relatively large value (for example, equal to or greater than the critical pressure ratio P0) in the operating state of the engine 1, and is set to a value close to 1 (for example, about 0.95). Furthermore, "when the pressure ratio equivalent value A or the sensor pressure ratio B is equal to or greater than the predetermined value D" corresponds to "when the pressure ratio is relatively high" related to the implementation conditions of the second control.

[0028] The conditions under which the corrected pressure ratio calculation unit 13 starts calculating the corrected pressure ratio C are as follows. Condition 1: When the pressure ratio equivalent value A and the sensor pressure ratio B are below the predetermined value D, the pressure ratio equivalent value A becomes equal to or greater than the predetermined value D before the sensor pressure ratio B. Condition 2: When the pressure ratio equivalent value A and the sensor pressure ratio B are both below the predetermined value D, the sensor pressure ratio B becomes equal to or greater than the predetermined value D before the pressure ratio equivalent value A becomes equal to or greater than the predetermined value D.

[0029] The conditions under which the corrected pressure ratio calculation unit 13 ends the calculation of the corrected pressure ratio C are, for example, the following conditions 3 and 4. Alternatively, condition 5 may be used instead of conditions 3 and 4. Condition 3: After the above condition 1 is met, if the pressure ratio equivalent value A becomes less than the predetermined value D Condition 4: After the above condition 2 is met, if the sensor pressure ratio B becomes less than the predetermined value D Condition 5: After the above conditions 1 and 2 are met, if the pressure ratio equivalent value A and the sensor pressure ratio B become less than the predetermined value D

[0030] When one of the pressure ratio equivalent value A and the sensor pressure ratio B reaches or exceeds a predetermined value D before the other, the corrected pressure ratio calculation unit 13 sets the value of the sensor pressure ratio B at that time as the initial value of the corrected pressure ratio C. Furthermore, the corrected pressure ratio calculation unit 13 increases the value of the corrected pressure ratio C so that the value of the corrected pressure ratio C also reaches 1 when the pressure ratio equivalent value A reaches 1. In other words, the pressure ratio equivalent value A is a value that reflects the driver's request (a value equivalent to the target torque of the engine 1). However, when the pressure ratio is rising in a relatively high state, the difference between the pressure ratio equivalent value A and the sensor pressure ratio B may become large, and if the throttle opening is controlled using the sensor pressure ratio B, the driver's request may not be sufficiently reflected. Therefore, a corrected pressure ratio C having an intermediate value between the pressure ratio equivalent value A and the sensor pressure ratio B is calculated so that this can be used to control the throttle opening.

[0031] For example, when condition 1 is met (when pressure ratio equivalent value A becomes equal to or greater than predetermined value D before sensor pressure ratio B), corrected pressure ratio calculation unit 13 calculates corrected pressure ratio C based on the following formula 1.

[0032]

number

[0033] In addition, when condition 2 is met (when the sensor pressure ratio B becomes equal to or greater than the predetermined value D before the pressure ratio equivalent value A), the corrected pressure ratio calculation unit 13 calculates the corrected pressure ratio C based on the following equation 2.

[0034]

number

[0035] Here, the value of pressure ratio equivalent value A at the time when pressure ratio equivalent value A or sensor pressure ratio B becomes equal to or greater than predetermined value D is defined as a first constant a, and the value of sensor pressure ratio B at the same time is defined as a second constant b. Corrected pressure ratio C is calculated by adding the second constant b to the product of the ratio of "the value obtained by subtracting the second constant b from 1" to "the value obtained by subtracting the first constant a from 1." In other words, the contents of the above equations 1 and 2 can be summarized as shown in the following equation 3.

[0036]

number

[0037] The control unit 20 controls the throttle opening based on the corrected pressure ratio C, and performs at least the second control described above. The control unit 20 of this embodiment has the function of performing a first control and a second control. In the first control, the throttle opening is controlled based on at least the sensor pressure ratio B, and in the second control, the throttle opening is controlled based on the corrected pressure ratio C. The first control is similar to the prior art (the background art in Japanese Patent No. 5598374, or Japanese Patent No. 5598374), so details thereof will be omitted.

[0038] 3 is a block diagram for explaining the control contents of the engine control device 10. The control unit 20 of the engine control device 10 is provided with a corrected flow velocity calculation unit 23, a target area calculation unit 25, a target throttle opening calculation unit 26, and a control voltage calculation unit 27. These elements are shown by classifying the functions of the control unit 20 for convenience.

[0039] The corrected flow velocity calculation unit 23 calculates the corrected flow velocity V of the air based on the corrected pressure ratio C. C Here, the corrected flow velocity V is calculated using different methods depending on the conditions under which the calculation of the corrected pressure ratio C is started. C First, when the calculation of the corrected pressure ratio C is started due to the establishment of condition 1 (when the corrected pressure ratio C is calculated based on equation 1), the corrected flow velocity V is calculated using the larger value of the sensor pressure ratio B or the corrected pressure ratio C. C Calculate.

[0040] In other words, the sensor pressure ratio B and the corrected pressure ratio C are maximized, and the corrected flow velocity V C On the other hand, when the calculation of the corrected pressure ratio C is started because the condition 2 is satisfied (when the corrected pressure ratio C is calculated based on the formula 2), the corrected pressure ratio C is used as it is to calculate the corrected flow velocity V C In other words, simply calculate the corrected flow velocity V corresponding to the corrected pressure ratio C. C is calculated.

[0041] The corrected flow velocity calculation unit 23 stores in advance a control map, a formula, etc. that define the relationship between the pressure ratio and the flow velocity. The corrected flow velocity calculation unit 23 calculates the corrected flow velocity V based on the relationship between the pressure ratio and the flow velocity, for example, as shown in FIG. C The corrected flow velocity V C This information is transmitted to the target area calculation unit 25.

[0042] The target area calculation unit 25 calculates the target area of ​​the throttle valve 3 (the target value of the opening area through which air passes) based on the target flow rate of intake air, which is set according to the target torque of the engine 1, and the flow velocity of air passing through the throttle valve 3. The target area of ​​the throttle valve 3 is calculated by dividing the target flow rate by a value obtained by multiplying the air flow velocity by a correction coefficient. The correction coefficient is a value that is calculated taking into account changes in air density due to temperature, and is set based on, for example, the intake temperature detected by the intake air temperature sensor 7 or the upstream pressure detected by the upstream pressure sensor 5. Under the circumstances where the corrected pressure ratio calculation unit 13 is calculating the corrected pressure ratio C, the corrected flow velocity V calculated by the corrected flow velocity calculation unit 23 isC is referred to, and the target area of ​​the throttle valve 3 is calculated.

[0043] The target throttle opening calculation unit 26 calculates the throttle opening corresponding to the target area calculated by the target area calculation unit 25. The target throttle opening calculation unit 26 stores in advance a control map, a formula, etc. that define the relationship between the target area and the target throttle opening. The control voltage calculation unit 27 calculates a control voltage for the throttle valve 3 corresponding to the target throttle opening calculated by the target throttle opening calculation unit 26, and outputs the control voltage to the throttle valve 3. This controls the operating state of the throttle valve 3 so that the throttle opening becomes the target throttle opening. The control voltage calculation unit 27 stores in advance a control map, a formula, etc. that define the relationship between the target throttle opening and the control voltage.

[0044] [3. Effect] FIG. 4(A) is a graph illustrating the change in the corrected pressure ratio C when the pressure ratio equivalent value A and the sensor pressure ratio B are both less than a predetermined value D, and then the pressure ratio equivalent value A reaches or exceeds the predetermined value D before the sensor pressure ratio B does. Time t1 is the time when the pressure ratio equivalent value A reaches the predetermined value D before the sensor pressure ratio B does. Here, the value of the pressure ratio equivalent value A at time t1 is set to A1, and the value of the sensor pressure ratio B at time t1 is set to B1. The initial value of the corrected pressure ratio C is set to B1.

[0045] Thereafter, the value of the corrected pressure ratio C is set to reach 1 at time t2 when the pressure ratio equivalent value A reaches 1. That is, the value of the corrected pressure ratio C is calculated according to the value of the pressure ratio equivalent value A so that the corrected pressure ratio C changes from B1 to 1 while the pressure ratio equivalent value A changes from a predetermined value D (= A1) to 1. If the corrected pressure ratio C is considered to be a linear function of the pressure ratio equivalent value A, the increment of the corrected pressure ratio C per unit pressure ratio equivalent value can be expressed as (1-B1) ÷ (1-D) or (1-B1) ÷ (1-A1). On the other hand, the increment of the pressure ratio equivalent value A with respect to time t1 can be expressed as (AD) or (A-A1). Therefore, it can be seen that the corrected pressure ratio C can be calculated using the above equation 1.

[0046] Between time t1 and time t2, the corrected pressure ratio C gradually approaches a value closer to the sensor pressure ratio B to a value closer to the pressure ratio equivalent value A, and is always equal to or greater than the sensor pressure ratio B. Therefore, the corrected flow velocity V C is calculated based on the corrected pressure ratio C, and the corrected flow velocity V C The throttle opening is controlled based on the corrected pressure ratio C. When the corrected pressure ratio C reaches 1 at time t2, the throttle opening is controlled to a predetermined opening (for example, fully open). At this time, the corrected pressure ratio C gradually approaches a value closer to the pressure ratio equivalent value A, so that the throttle opening is stably maintained at the predetermined opening even if the value of the sensor pressure ratio B changes.

[0047] When the pressure ratio equivalent value A starts to decrease from 1 at time t3, the corrected pressure ratio C also starts to decrease from 1 accordingly. The value of the corrected pressure ratio C thereafter becomes B1 at time t4 when the pressure ratio equivalent value A drops to a predetermined value D. The same applies if the corrected pressure ratio C starts to decrease without reaching 1. After time t3, the sensor pressure ratio B decreases with a delay from the pressure ratio equivalent value A, so the difference between the actual pressure ratio (sensor pressure ratio B) and the corrected pressure ratio C becomes excessive. For this reason, the sensor pressure ratio B and the corrected pressure ratio C are maximized, and the corrected flow velocity V corresponding to the larger value is calculated. C and calculate the corrected flow velocity V C The throttle opening is controlled based on the

[0048] The calculation of the corrected pressure ratio C, which started at time t1, ends at time t4 when the pressure ratio equivalent value A falls to a predetermined value D. After time t4, conventional throttle opening control based on the pressure ratio equivalent value A or the sensor pressure ratio B is performed.

[0049] FIG. 4(B) is a graph illustrating the change in corrected pressure ratio C when the pressure ratio equivalent value A and the sensor pressure ratio B are both less than a predetermined value D, and then the sensor pressure ratio B reaches or exceeds the predetermined value D before the pressure ratio equivalent value A does. Time t5 is the time when the sensor pressure ratio B reaches the predetermined value D before the pressure ratio equivalent value A does. Here, the value of the pressure ratio equivalent value A at time t5 is set to A2, and the value of the sensor pressure ratio B at time t5 is set to B2. The initial value of the corrected pressure ratio C is set to B2 (=D).

[0050] Thereafter, the value of the corrected pressure ratio C is set to reach 1 at time t6 when the pressure ratio equivalent value A reaches 1. In other words, the value of the corrected pressure ratio C is calculated according to the value of the pressure ratio equivalent value A so that the corrected pressure ratio C changes from B2 (= D) to 1 while the pressure ratio equivalent value A changes from A2 to 1. If the corrected pressure ratio C is considered to be a linear function of the pressure ratio equivalent value A, the increment of the corrected pressure ratio C per unit pressure ratio equivalent value can be expressed as (1 - D) ÷ (1 - A2) or (1 - B2) ÷ (1 - A2). On the other hand, the increment of the pressure ratio equivalent value A with respect to time t5 can be expressed as (A - A2). Therefore, it can be seen that the corrected pressure ratio C can be calculated using Equation 2 above.

[0051] Between time t5 and time t6, the value of the corrected pressure ratio C gradually approaches from a value closer to the sensor pressure ratio B to a value closer to the pressure ratio equivalent value A. When the corrected pressure ratio C reaches 1 at time t6, the throttle opening is controlled to a predetermined opening (for example, fully open). In this section (between time t5 and time t7), the corrected flow velocity V C is calculated based on the corrected pressure ratio C, and the corrected flow velocity V CAt this time, as can be seen from Equation 2, the corrected pressure ratio C does not depend on the value of the sensor pressure ratio B after the predetermined value D, so even if the sensor pressure ratio B changes significantly, the predetermined throttle opening is stably maintained.

[0052] When the pressure ratio equivalent value A starts to decrease from 1 at time t7, the corrected pressure ratio C also starts to decrease from 1 accordingly. The value of the corrected pressure ratio C thereafter becomes B2 at time t8 when the sensor pressure ratio B drops to a predetermined value D. The corrected pressure ratio C from time t7 onwards gradually approaches a value closer to the pressure ratio equivalent value A to a value closer to the sensor pressure ratio B, and at time t8 there is no deviation between the actual pressure ratio (sensor pressure ratio B) and the corrected pressure ratio C. Therefore, it is not necessary to take the maximum value between the sensor pressure ratio B and the corrected pressure ratio C, and the corrected flow velocity V corresponding to the corrected pressure ratio C is C and calculate the corrected flow velocity V C The throttle opening is controlled based on the

[0053] The calculation of the corrected pressure ratio C, which began at time t5, ends, for example, at time t8 when the sensor pressure ratio B drops to a predetermined value D (or at time t8 when the pressure ratio equivalent value A drops to A2). After time t8, similar to after time t4 in FIG. 4A, conventional throttle opening control based on the pressure ratio equivalent value A or the sensor pressure ratio B is performed.

[0054] [4. Effects] (1) The engine control device 10 of this embodiment includes a pressure ratio equivalent value calculation unit 11, a sensor pressure ratio calculation unit 12, a corrected pressure ratio calculation unit 13, and a control unit 20. The pressure ratio equivalent value calculation unit 11 calculates a pressure ratio equivalent value A, which is the ratio of a target torque equivalent value to a maximum torque equivalent value of the engine 1. The sensor pressure ratio calculation unit 12 calculates a sensor pressure ratio B, which is the ratio of a downstream pressure to an upstream pressure of the throttle valve 3. The corrected pressure ratio calculation unit 13 calculates a corrected pressure ratio C based on the pressure ratio equivalent value A and the sensor pressure ratio B when the pressure ratio equivalent value A or the sensor pressure ratio B is equal to or greater than a predetermined value D. The control unit 20 controls the opening of the throttle valve 3 based on the corrected pressure ratio C.

[0055] In this way, when the pressure ratio equivalent value A or the sensor pressure ratio B is equal to or greater than the predetermined value D, the corrected pressure ratio C is calculated and the opening of the throttle valve 3 is controlled based on the corrected pressure ratio C, thereby suppressing fluctuations in the throttle opening due to minute fluctuations in the sensor pressure ratio B. This makes it possible to increase the stability of the throttle opening and improve the control accuracy of the engine torque. Furthermore, when the pressure ratio equivalent value A or the sensor pressure ratio B is less than the predetermined value D, conventional control based on the pressure ratio equivalent value A or the sensor pressure ratio B can be performed, making it possible to set the throttle opening according to the actual pressure ratio (sensor pressure ratio B), and improving the control accuracy of the engine torque.

[0056] (2) When one of the pressure ratio equivalent value A and the sensor pressure ratio B reaches or exceeds a predetermined value D before the other, the corrected pressure ratio calculation unit 13 sets the value of the sensor pressure ratio B at that time (B1, B2) to the initial value of the corrected pressure ratio C, and is capable of performing a calculation to increase the value of the corrected pressure ratio C so that the value of the corrected pressure ratio C also reaches 1 at the time (t2, t6) when the pressure ratio equivalent value A reaches 1.

[0057] In this way, by matching the initial value of the corrected pressure ratio C with the value of the sensor pressure ratio B, it is possible to prevent a sudden change in the throttle opening. Also, by increasing the value of the corrected pressure ratio C so that the value of the corrected pressure ratio C also reaches 1 when the pressure ratio equivalent value A reaches 1, it is possible to gradually open the throttle to a predetermined opening (for example, a fully open state). Therefore, it is possible to further improve the stability of the throttle opening.

[0058] (3) The corrected pressure ratio calculation unit 13 can calculate the corrected pressure ratio C by defining the value of the pressure ratio equivalent value A at the time when the pressure ratio equivalent value A or the sensor pressure ratio B becomes equal to or greater than a predetermined value D as a first constant a, defining the value of the sensor pressure ratio B at the same time as a second constant b, and adding the second constant b to the product of the ratio of the value obtained by subtracting the first constant a from 1 to the value obtained by subtracting the first constant a from the pressure ratio equivalent value A at that time.

[0059] In this way, by regarding the corrected pressure ratio C as a linear function of the pressure ratio equivalent value A, it is possible to easily and accurately calculate the corrected pressure ratio C according to the pressure ratio equivalent value A. Therefore, it is possible to increase the stability of the throttle opening with a simple configuration and improve the control accuracy of the engine torque. Furthermore, since the calculation of the corrected pressure ratio C can be completed in an extremely short time, it is possible to improve the responsiveness of the throttle opening and engine torque.

[0060] (4) The corrected pressure ratio calculation unit 13 can calculate the corrected pressure ratio C based on Equation 1 when the pressure ratio equivalent value A becomes equal to or greater than the predetermined value D before the sensor pressure ratio B. This makes it possible to easily and accurately calculate the corrected pressure ratio C when Condition 1 is met. (5) The corrected pressure ratio calculation unit 13 can calculate the corrected pressure ratio C based on Equation 2 when the sensor pressure ratio B becomes equal to or greater than the predetermined value D before the pressure ratio equivalent value A becomes equal to or greater than the predetermined value D. This makes it possible to easily and accurately calculate the corrected pressure ratio C when Condition 2 is met.

[0061] (6) When the pressure ratio equivalent value A reaches or exceeds the predetermined value D before the sensor pressure ratio B, the control unit 20 can control the throttle opening using the larger of the sensor pressure ratio B and the corrected pressure ratio C. For example, the corrected flow velocity V C Calculate the corrected flow velocity V C With this configuration, even if a corrected pressure ratio C that is too small and deviates from the actual pressure ratio (sensor pressure ratio B) is calculated, the throttle opening can be controlled using the sensor pressure ratio B. Therefore, the control accuracy of the engine torque can be improved.

[0062] (7) When the sensor pressure ratio B reaches or exceeds the predetermined value D before the pressure ratio equivalent value A, the control unit 20 can control the throttle opening using only the corrected pressure ratio C, rather than using the larger of the sensor pressure ratio B and the corrected pressure ratio C. In this way, in a situation where an excessively small corrected pressure ratio C that deviates from the actual pressure ratio (sensor pressure ratio B) is not calculated, the control configuration can be simplified by controlling the throttle opening using only the corrected pressure ratio C.

[0063] [5. Other] The above-described embodiment is merely illustrative, and does not intend to exclude various modifications or applications of techniques not explicitly stated in the present embodiment. The configurations of the present embodiment can be modified in various ways without departing from the spirit of the present embodiment. Furthermore, the configurations of the present embodiment can be selected or appropriately combined as needed. For example, while the above-described embodiment illustrates an engine control device 10 applied to an engine 1 mounted on a vehicle, the application of the engine control device 10 is not limited to automobile engines.

[0064] In the above embodiment, when the pressure ratio equivalent value A or the sensor pressure ratio B is equal to or greater than the predetermined value D, the corrected flow velocity V calculated from the corrected pressure ratio C (or the larger of the sensor pressure ratio B and the corrected pressure ratio C) is C However, the details of this control can be changed as appropriate, and the specific calculation formula for the corrected pressure ratio C and the relationship between the corrected pressure ratio C and the throttle opening can also be changed.

[0065] For example, in the above embodiment, the corrected pressure ratio C is expressed as a linear function of the pressure ratio equivalent value A (Equations 1 to 3), but the corrected pressure ratio C may also be expressed as a sigmoid function or a logistic function of the pressure ratio equivalent value A. Alternatively, the relationship between the corrected pressure ratio C and the pressure ratio equivalent value A may be defined in advance in a control map, and the value of the corrected pressure ratio C may be calculated using that control map. At the very least, by smoothly changing the value of the corrected pressure ratio C so that there is no large deviation between the actual pressure ratio (sensor pressure ratio B) and the corrected pressure ratio C, it is possible to obtain the same functions and effects as the above embodiment.

[0066] [6. Notes] The following notes are provided regarding the above-described embodiments and modifications. [Appendix 1] a pressure ratio equivalent value calculation unit that calculates a pressure ratio equivalent value, which is a ratio of a target torque equivalent value of the engine to a maximum torque equivalent value of the engine; a sensor pressure ratio calculation unit that calculates a sensor pressure ratio, which is a ratio of a downstream pressure to an upstream pressure of the throttle valve; a corrected pressure ratio calculation unit that calculates a corrected pressure ratio based on the pressure ratio equivalent value and the sensor pressure ratio when the pressure ratio equivalent value or the sensor pressure ratio is equal to or greater than a predetermined value; a control unit that controls the opening degree of the throttle valve based on the corrected pressure ratio. An engine control device characterized by:

[0067] [Appendix 2] When one of the pressure ratio equivalent value and the sensor pressure ratio becomes equal to or greater than the predetermined value before the other, the corrected pressure ratio calculation unit sets the value of the sensor pressure ratio at that time to an initial value of the corrected pressure ratio, and increases the value of the corrected pressure ratio so that the value of the corrected pressure ratio also reaches 1 when the pressure ratio equivalent value reaches 1. 2. An engine control device according to claim 1.

[0068] [Appendix 3] The corrected pressure ratio calculation unit calculates the corrected pressure ratio by setting a value of the pressure ratio equivalent value at a time when the pressure ratio equivalent value or the sensor pressure ratio becomes equal to or greater than the predetermined value as a first constant, setting a value of the sensor pressure ratio at the same time as a second constant, and adding the second constant to the product of the ratio of "the value obtained by subtracting the second constant from 1" to "the value obtained by subtracting the constant number from 1." 3. The engine control device according to claim 1 or 2.

[0069] The corrected pressure ratio calculation unit may calculate the corrected pressure ratio based on the following equation 3.

number

[0070] [Appendix 4] The corrected pressure ratio calculation unit calculates the corrected pressure ratio based on the following formula 1 when the pressure ratio equivalent value becomes equal to or greater than the predetermined value before the sensor pressure ratio: 4. The engine control device according to any one of claims 1 to 3.

[0071]

number

[0072] [Appendix 5] The corrected pressure ratio calculation unit calculates the corrected pressure ratio based on the following equation 2 when the sensor pressure ratio becomes equal to or greater than the predetermined value before the pressure ratio equivalent value: 5. The engine control device according to any one of claims 1 to 4.

[0073]

number

[0074] [Appendix 6] When the pressure ratio equivalent value becomes equal to or greater than the predetermined value before the sensor pressure ratio, the control unit controls the opening degree of the throttle valve using the larger of the sensor pressure ratio and the corrected pressure ratio. 6. The engine control device according to any one of claims 1 to 5.

[0075] [Appendix 7] When the sensor pressure ratio reaches or exceeds the predetermined value before the pressure ratio equivalent value, the control unit controls the opening degree of the throttle valve using only the corrected pressure ratio out of the sensor pressure ratio and the corrected pressure ratio. 7. The engine control device according to any one of claims 1 to 6. [Industrial Applicability]

[0076] The present invention is applicable to the engine control unit manufacturing industry and also to the vehicle manufacturing industry that incorporates the engine control unit. [Explanation of symbols]

[0077] 1 engine 2 Intake manifold 3 Throttle valve 4 Intake manifold pressure sensor 5 Upstream pressure sensor 6 Airflow Sensor 7 Intake air temperature sensor 8 Engine speed sensor 9. Accelerator opening sensor 10 Engine control device 11 Pressure ratio equivalent value calculation section 12 Sensor pressure ratio calculation section 13 Corrected pressure ratio calculation section 20 Control Unit A Pressure ratio equivalent value B sensor pressure ratio C Corrected pressure ratio D Predetermined value

Claims

1. a pressure ratio equivalent value calculation unit that calculates a pressure ratio equivalent value, which is a ratio of a target torque equivalent value of the engine to a maximum torque equivalent value of the engine; a sensor pressure ratio calculation unit that calculates a sensor pressure ratio, which is a ratio of a downstream pressure to an upstream pressure of the throttle valve; a corrected pressure ratio calculation unit that calculates a corrected pressure ratio based on the pressure ratio equivalent value and the sensor pressure ratio when the pressure ratio equivalent value or the sensor pressure ratio is equal to or greater than a predetermined value; a control unit that controls an opening degree of the throttle valve based on the corrected pressure ratio, When the pressure ratio equivalent value becomes equal to or greater than the predetermined value before the sensor pressure ratio, the control unit controls the opening degree of the throttle valve using the larger of the sensor pressure ratio and the corrected pressure ratio. An engine control device characterized by:

2. When one of the pressure ratio equivalent value and the sensor pressure ratio becomes equal to or greater than the predetermined value before the other, the corrected pressure ratio calculation unit sets the value of the sensor pressure ratio at that time to an initial value of the corrected pressure ratio, and increases the value of the corrected pressure ratio so that the value of the corrected pressure ratio also reaches 1 when the pressure ratio equivalent value reaches 1.

2. The engine control device according to claim 1.

3. The corrected pressure ratio calculation unit calculates the corrected pressure ratio by setting a value of the pressure ratio equivalent value at a time point when the pressure ratio equivalent value or the sensor pressure ratio becomes equal to or greater than the predetermined value as a first constant, setting a value of the sensor pressure ratio at the same time point as a second constant, and adding the second constant to the product of the ratio of "a value obtained by subtracting the second constant from 1" to "a value obtained by subtracting the constant number from 1." 2. The engine control device according to claim 1.

4. The corrected pressure ratio calculation unit calculates the corrected pressure ratio based on the following equation 1 when the pressure ratio equivalent value becomes equal to or greater than the predetermined value before the sensor pressure ratio becomes equal to or greater than the predetermined value:

2. The engine control device according to claim 1. [Equation 1] A: Pressure ratio equivalent value, B: Sensor pressure ratio, C: Corrected pressure ratio, D: Predetermined value B １ : The value of the sensor pressure ratio B at the time when the pressure ratio equivalent value A becomes equal to or greater than the predetermined value D (B １ <D)

5. The corrected pressure ratio calculation unit calculates the corrected pressure ratio so that the sensor pressure ratio reaches the predetermined value before the pressure ratio equivalent value reaches the predetermined value. If this is the case, the corrected pressure ratio is calculated based on the following formula 2:

2. The engine control device according to claim 1. [Equation 2] A: Pressure ratio equivalent value, B: Sensor pressure ratio, C: Corrected pressure ratio, D: Predetermined value A ２ : The value of the pressure ratio equivalent value A at the time when the sensor pressure ratio B becomes equal to or greater than the predetermined value D (A ２ <D)

6. When the sensor pressure ratio reaches or exceeds the predetermined value before the pressure ratio equivalent value, the control unit controls the opening degree of the throttle valve using only the corrected pressure ratio out of the sensor pressure ratio and the corrected pressure ratio.

2. The engine control device according to claim 1.

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