Search

DE-112019004621-B4 - Engine control device and engine control method

DE112019004621B4DE 112019004621 B4DE112019004621 B4DE 112019004621B4DE-112019004621-B4

Abstract

Engine control unit (ECU 102), with: a target torque calculation unit (203) designed to calculate a target torque of a motor for which torque-based motor control is performed using an estimated torque; and a unit (210) for calculating the estimated torque, which is designed to calculate the estimated torque by performing primary delay processing on the target torque using a primary delay coefficient equivalent to a time constant calculated for each control cycle on the basis of a change in an actual intake air quantity with respect to a target intake air quantity of the air drawn into the engine, where the unit (210) is used to calculate the estimated torque: a target intake air quantity calculation unit (300) designed to calculate a target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed, and a unit (301) for calculating the Primary delay coefficient, designed to calculate the primary delay coefficient equivalent to the time constant calculated on the basis of the target intake air volume and the actual intake air volume, and a primary delay processing unit (302) designed to calculate the estimated torque by performing primary delay processing of the target torque based on the target torque and the primary delay coefficient, wherein the unit (210) for calculating the estimated torque further includes a processing unit (401) for divergence prevention, which is designed to switch the primary delay coefficient calculated by the unit (301) for calculating the primary delay coefficient to a different value in order to prevent a divergence of the primary delay coefficient if the divergence occurs in the calculation of the primary delay coefficient performed by the unit (301) for calculating the primary delay coefficient.

Inventors

  • Yoshimasa Ishikawa
  • Shinya Sato

Assignees

  • HITACHI ASTEMO, LTD.

Dates

Publication Date
20260513
Application Date
20191018
Priority Date
20181112

Claims (13)

  1. Motor control device (ECU 102), comprising: a target torque calculation unit (203) designed to calculate a target torque of a motor for which torque-based motor control is performed using an estimated torque; and a unit (210) for calculating the estimated torque, designed to calculate the estimated torque by performing primary delay processing on the target torque using a primary delay coefficient equivalent to a time constant calculated for each control cycle based on a change in an actual intake air quantity relative to a target intake air quantity of the air drawn into the engine, where the unit (210) for calculating the estimated torque includes: a target intake air quantity calculation unit (300) designed to calculate a target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed, and a unit (301) for calculating the primary delay coefficient, designed to calculate the primary delay coefficient equivalent to the time constant calculated based on the target intake air quantity and the actual intake air quantity. is calculated, and a primary delay processing unit (302) designed to calculate the estimated torque by performing primary delay processing of the target torque based on the target torque and the primary delay coefficient, where the unit (210) for calculating the estimated torque further includes a divergence prevention processing unit (401) designed to switch the primary delay coefficient calculated by the unit (301) for calculating the primary delay coefficient to a different value in order to prevent divergence of the primary delay coefficient if the divergence occurs in the calculation of the primary delay coefficient performed by the unit (301) for calculating the primary delay coefficient.
  2. Engine control unit (ECU 102) according to Claim 1 , wherein the primary delay processing unit (302) is designed to calculate the estimated torque by performing primary delay processing on the target torque using the primary delay coefficient calculated in a transition state in which the target torque changes by a specified value or more within a specified time.
  3. Engine control unit (ECU 102) according to Claim 1 , wherein the unit (301) for calculating the primary delay coefficient is designed to calculate the primary delay coefficient in a transition state in which the current intake air volume changes by a set value or more within a specified time.
  4. Engine control unit (ECU 102) according to Claim 1 , wherein the primary delay processing unit (302) is designed to calculate the target torque as the estimated torque in a steady state in which the target intake air quantity and the actual intake air quantity are equal.
  5. Engine control unit (ECU 102) according to Claim 1 , which further comprises an ignition timing correction unit (215) designed to correct an ignition timing for the ignition of the fuel injected into a cylinder of the engine so that the estimated torque becomes the target torque.
  6. Engine control unit (ECU 102) according to Claim 1 , which further comprises a fuel shut-off control unit (216) designed to perform a fuel shut-off for one cylinder of the engine so that the estimated torque becomes the target torque.
  7. Engine control unit (ECU 102) according to Claim 1 , which further includes a fuel injection quantity control unit designed to correct a fuel injection quantity from a fuel injector sending fuel to a cylinder of the engine so that the estimated torque becomes the target torque.
  8. Engine control unit (ECU 102) according to Claim 1 , wherein the unit (210) for calculating the estimated torque further comprises: a primary delay coefficient limiting processing unit (501) designed to limit the primary delay coefficient input by the processing unit (401) for divergence prevention and to output the primary delay coefficient to the primary delay processing unit (302), and a second primary delay processing unit (404) designed to perform the primary delay processing of the target intake air quantity and to calculate an estimated intake air quantity of the engine based on the target intake air quantity and the primary delay coefficient limited by the primary delay coefficient limiting processing unit, and the primary delay coefficient calculation unit (301) designed to calculate the primary delay coefficient using a previous value of the estimated intake air quantity instead of a previous value of the current intake air quantity.
  9. Engine control unit (ECU 102) according to Claim 8 , wherein the unit (210) for calculating the estimated torque further includes a constant delay processing unit (400) designed to perform filter processing with a delay coefficient as a constant to reduce the vibration of the current intake air volume, and the unit (301) for calculating the primary delay coefficient is designed to calculate the primary delay coefficient based on the target intake air volume, the current intake air volume on which the filter processing is performed, and the estimated intake air volume input from the second primary delay processing unit (404).
  10. Engine control unit (ECU 102) according to Claim 1 , wherein the unit (210) for calculating the estimated torque further comprises: a constant delay processing unit (400) designed to perform filter processing with a delay coefficient as a constant to reduce the vibration of the current intake air volume, and an offset processing unit (500) designed to perform offset processing on the current intake air volume on which the filter processing is performed by the constant delay processing unit (400) using an offset value obtained in a steady state in which the target intake air volume and the current intake air volume are equal, and the primary delay coefficient calculation unit (301) designed to calculate the primary delay coefficient based on the target intake air volume, the current intake air volume on which the offset processing is performed, and an estimated intake air volume of the engine.
  11. Engine control unit (ECU 102) according to Claim 10 , wherein the unit (210) for calculating the estimated torque also comprises: a second primary delay coefficient limiting processing unit (501) designed to limit the primary delay coefficient by switching a lower limit of the primary delay coefficient, the divergence of which is prevented by the divergence prevention processing unit (401), to a different value, and a second primary delay processing unit (404) designed to calculate the estimated intake air quantity of the engine by performing the primary delay processing of the target intake air quantity and outputting the estimated intake air quantity to the primary delay coefficient calculation unit, based on the target intake air quantity and the primary delay coefficient limited by the second primary delay coefficient limiting processing unit (501).
  12. Engine control unit (ECU 102) according to Claim 1 , wherein the unit (210) for calculating the estimated torque includes: a storage unit (621) for past primary delay coefficients, designed to store a primary delay coefficient used in the past, a determination unit (622) for using a past primary delay coefficient, designed to determine one of the two primary delay coefficients used, wherein one primary delay coefficient is output by the primary delay coefficient calculation unit and the other primary delay coefficient is stored in the storage unit (621) for the past primary delay coefficient and in a specific The control scene was used in the past, and outputs a determination result, and a primary delay coefficient switching unit (623) designed to switch a primary delay coefficient to any of the primary delay coefficient read from the memory unit (621) for past primary delay coefficients and the primary delay coefficient calculated by the primary delay calculation unit, and output the primary delay coefficient based on the determination result when the behavior of the engine is limited in a transition state in which the current intake air quantity changes by a set value or more within a specified time, and the primary delay processing unit (302) designed to perform primary delay processing based on the target torque and the primary delay coefficient selected by the primary delay coefficient switching unit (623), and to calculate the estimated torque of the engine in the transition state.
  13. A method for engine control, comprising: Calculating a target torque of an engine for which torque-based engine control is performed using an estimated torque; Calculating a time constant for each control cycle based on a change in the current intake air volume relative to a target intake air volume of the air drawn into the engine; Calculating a primary delay coefficient equivalent to the time constant; and calculating the estimated torque by performing primary delay processing on the target torque using the primary delay coefficient, calculating a target intake air quantity based on the target torque input by the target torque calculation unit (203) and an engine speed, and calculating the primary delay coefficient equivalent to the time constant calculated on the basis of the target intake air quantity and the actual intake air quantity, calculating the estimated torque by performing primary delay processing on the target torque based on the target torque and the primary delay coefficient, where the calculation of the estimated torque further includes divergence prevention, which switches the calculated primary delay coefficient to a different value to prevent divergence of the primary delay coefficient if the divergence occurs during the calculation of the primary delay coefficient.

Description

Technical area The present invention relates to a motor control device and a motor control method for carrying out torque-based (torque request) motor control. background Torque-based (torque-demand) engine control has been used in practice as one of the control methods for an engine with an electronically controlled throttle valve (hereinafter referred to as "electronically controlled throttle valve"). Torque-based engine control is a control method capable of performing throttle valve control, fuel control, ignition control, and similar functions to calculate the engine's target torque based on accelerator pedal opening and engine speed, in order to achieve both the target torque and a target air-fuel ratio. Torque control in torque-based engine management comprises two types: low-response torque control, achieved via an intake air volume operation represented by electronic throttle actuation, and high-response torque control, achieved without an intake air volume operation, represented by ignition retardation or fuel cut-off. Two target torque values, the low-response target torque and the high-response target torque, are defined for each torque control method. The basis of the torque control system is low-response torque control via the electronic throttle. With low-response torque control, the target torque is set as a low-response target torque. However, if the target torque changes in a complex manner at high engine speeds, it is difficult to generate the engine torque in accordance with the target torque simply by actuating the electronic throttle, due to a delay in the intake air response. In such a situation, where the target torque changes in a complex manner at high engine speeds, the target torque is set as the high-response target torque, and the low-response target torque is set to a value equal to or greater than the high-response target torque. 1 This is a diagram showing an example of the time-dependent change of each torque and ignition timing correction amount when the target torque and the estimated torque are equal in a steady state. In this diagram, a horizontal axis represents time and a vertical axis represents torque. The diagram at the top of 1 Examples of a target torque with low response 11, a target torque with high response 12 and an estimated torque 13 are shown. In this specification, a period during which the target low-response torque (e.g., target low-response torque 11) changes by a specified value or more within a defined time is referred to as "transient." Furthermore, a period during which the target low-response torque (e.g., target low-response torque 11) and the estimated torque (e.g., estimated torque 13) are identical is referred to as "continuous." Since the torque does not change in the continuous state, sections 14 and 15 illustrate that both the target low-response torque 11 and the target high-response torque 12 are identical. In low-response torque control, engine torque is generated that exceeds the target torque. However, this excess, actually generated torque is adjusted in the decreasing direction, and high-response torque control, such as ignition retard and fuel cut-off, is performed in combination so that the estimated torque 13 matches the target high-response torque 12. An upper diagram of 1 This shows, for example, that a difference 16 arises between the target torque and the torque actually generated. Therefore, the estimated torque 13 is corrected to approximate the target torque 12 with high response by means of an ignition delay. or a fuel advance for the ignition timing (MBT: Minimum advance for the Best Torque) is implemented, maximizing torque as a correction amount for the ignition timing. That is, the control of the ignition delay or fuel advance implementation is carried out such that the electronic control throttle is opened further relative to the target torque to be achieved, in order to generate engine torque that exceeds the target torque, while simultaneously eliminating the difference 16 between the target torque and the torque actually produced. However, since there is currently no device that directly measures the motor torque, it is necessary to estimate the actual torque produced when implementing low-response torque control, in order to implement both low-response and high-response torque control. The estimated value of the actual torque produced, i.e., the estimated torque, is referred to as estimated torque 13 in the figure on the upper side of 1 The diagram shown illustrates this, as described above. The accuracy of the estimated torque 13 then affects the accuracy of the torque control in the transition state. Regarding the estimated torque calculation, the state of the art disclosed in PTLs 1 and 2 is known, for example. PTL 1 discloses a technique for correcting engine torque by correcting the ignition timing or similar according to a deviation between target torque and corrected estimated torque. PTL 2 discloses a tech