JP2010133256A - Engine ignition timing control device and ignition timing control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine ignition timing control device and an ignition timing control method, certainly suppressing knocking even during sudden acceleration. <P>SOLUTION: This engine ignition timing control device includes: a basic ignition timing calculation means (S3) calculating basic ignition timing based on the rotational speed and load of an engine; a cylinder gas temperature rise calculation means (S8) calculating a rise in temperature of cylinder gas according to a temperature difference between cylinder gas temperature at a predetermined timing during an engine transient operation and cylinder gas temperature when steady operation is performed at the rotational speed and load at the predetermined timing; correction amount calculation means (steps S11, S12) calculating the amount of correction of ignition timing based on the rise in temperature of cylinder gas; and an ignition timing calculation means (step S13) calculating the ignition timing during the transient operation by delaying the amount of correction from the basic ignition timing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus and method for controlling the ignition timing of an engine.

The invention of Patent Document 1 is a case where it is determined whether or not the current engine operation state is a high load state, that is, whether or not the engine operation state is such that the exhaust temperature rises, and the exhaust temperature rises. When the EGR gas is introduced into the cylinder, the ignition timing is controlled to the advance side. In this way, since the exhaust gas temperature is lowered, knocking can be suppressed.
JP 2007-46666 A

  In the above-described conventional device, the ignition timing is controlled (particularly, the ignition timing is advanced) in accordance with whether or not the current engine operating state is a high load state. However, the inventors have found that even if such control is performed, knocking cannot always be suppressed during rapid acceleration.

  The present invention has been made paying attention to such conventional problems, and an object of the present invention is to provide an ignition timing control device and an ignition timing control method for an engine that can reliably suppress knocking even during sudden acceleration. And

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention relates to basic ignition timing calculation means (step S3) for calculating basic ignition timing based on engine rotation speed and load, in-cylinder gas temperature at a predetermined timing during engine transient operation, and rotation speed at that timing. In-cylinder gas temperature increase amount calculating means (step S8) for calculating the increase amount of the in-cylinder gas temperature in accordance with the temperature difference between the in-cylinder gas temperature in the case of steady operation with a load, and the in-cylinder gas temperature Correction amount calculation means (steps S11 and S12) for calculating the correction amount of the ignition timing based on the amount of increase, and the ignition timing for calculating the ignition timing during transient operation by retarding the correction amount from the basic ignition timing And calculating means (step S13).

  According to the present invention, the in-cylinder gas temperature in accordance with the temperature difference between the in-cylinder gas temperature at a predetermined timing during the transient operation of the engine and the in-cylinder gas temperature in the case of steady operation at the rotational speed and load at that timing. Since the amount of temperature rise is calculated and the ignition timing is corrected to be retarded according to the amount of increase, the ignition timing can be retarded by an appropriate amount at an appropriate timing, thus reliably preventing knocking. be able to. Further, fuel consumption deterioration and drivability deterioration due to unnecessary correction of the ignition timing can be avoided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an embodiment of an engine ignition timing control apparatus according to the present invention.

  The ignition timing control device 1 includes a crank angle sensor 21, an airflow sensor 12, an intake pressure sensor 13, an ignition plug 14, and a controller 70, and includes the crank angle sensor 21, the airflow sensor 12, and the intake pressure sensor 13. The ignition timing of the spark plug 14 is controlled based on the signal.

  The crank angle sensor 21 detects the rotation of the crankshaft of the engine. The engine speed Ne can be calculated from this detection signal.

  The air flow sensor 12 detects the flow rate of air flowing through the intake passage 11.

  The intake pressure sensor 13 detects the pressure of air in the intake passage 11.

  The spark plug 14 ignites the air-fuel mixture in the cylinder.

  The controller 70 receives signals from the crank angle sensor 21, the airflow sensor 12, and the intake pressure sensor 13, and controls the ignition timing of the spark plug 14 based on these signals. The controller 70 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 70 may be composed of a plurality of microcomputers. Specific operations will be described later.

(Basic technical concept)
Here, in order to facilitate understanding of the present invention, a basic technical idea will be described.

  Conventionally, various methods for suppressing knocking during steady operation have been proposed. However, the inventors have found that even if the method is applied during rapid acceleration, knocking cannot always be suppressed. This will be described with reference to FIG.

  The upper line in FIG. 2 (A) shows the in-cylinder gas temperature change at the intake valve closing timing (IVC) in a state (transient state) in which the engine is fully opened from idle. The lower line in FIG. 2 (A) plots the in-cylinder gas temperature at the intake valve closing timing (IVC) at a steady operation at the engine speed and charging efficiency at the timing plotted with black circles on the upper line. It is a line that connects white circles.

  From FIG. 2A, it can be seen that the in-cylinder gas temperature is higher in the acceleration state (transient state) than in the steady state even if the engine speed and the charging efficiency are the same.

  FIG. 2B is a graph showing the relationship between the charging efficiency and the in-cylinder gas temperature at the intake valve opening timing (IVO) for each engine speed.

  That is, the line in FIG. 2 (B) plots the in-cylinder gas temperature at the intake valve opening timing (IVO) at a steady operation of the engine at a predetermined rotational speed and charging efficiency (load), and the engine rotational speed. Each line is connected.

  Even during sudden acceleration, the engine rotation speed is almost constant when viewed in a short time, and it can be considered that the charging efficiency (load) is increased. When the charging efficiency (load) increases while the engine speed remains constant, it is understood that the in-cylinder gas temperature at the intake valve opening timing (IVO) decreases as shown in FIG. . That is, at the time of rapid acceleration, there is a residue of gas that has a high filling efficiency (load) and is high temperature, and the in-cylinder gas temperature becomes high due to the influence of this residue. Therefore, as shown in FIG. 2A, the inventors have found that the in-cylinder gas temperature is higher in the acceleration state than in the steady state.

  Knocking is easier if the in-cylinder gas temperature is high. Even if the engine speed and load are the same, the in-cylinder gas temperature is higher in the acceleration state (transient state) than in the steady state. Therefore, it is easier to knock in the acceleration state (transient state) than in the steady state. Therefore, the inventors tried to prevent knocking by accurately estimating the in-cylinder gas temperature according to the operating state of the engine and correcting the ignition timing according to the in-cylinder gas temperature. The specific engine ignition timing control device logic of the controller 70 will be described below with reference to flowcharts.

  FIG. 3 is a main flowchart for explaining the operation of the engine ignition timing control apparatus according to the present invention. The controller 70 repeatedly executes this process in a minute time cycle (for example, a cycle of 10 milliseconds or a cycle for each Ref signal).

  In step S1, the controller 70 detects the engine rotational speed Ne based on the signal from the crank angle sensor.

  In step S2, the controller 70 detects the engine load (charging efficiency Itac) of the #n cylinder to be ignited next time. Specifically, for example, it may be calculated from the ratio of the intake air amount detected by the air flow sensor 12 to the combustion chamber volume. Alternatively, the intake air amount may be estimated from the intake pressure detected by the intake pressure sensor 13 and the intake air temperature detected from the outside air temperature sensor, and calculated using the intake air amount.

  In step S3, the controller 70 sets the basic ignition timing base_adv [degBTDC] of the #n cylinder to be ignited next time. Specifically, the basic ignition timing base_adv [degBTDC] is set by applying the engine rotational speed Ne and the charging efficiency Itac to a characteristic map shown in FIG. 4 stored in advance in the ROM, for example.

  In step S4, the controller 70 sets the filling efficiency threshold Itac0 [%]. Specifically, the charging efficiency threshold Itac0 [%] is set by applying the engine rotational speed Ne to a characteristic map shown in FIG. The filling efficiency threshold Itac0 is a reference value for determining whether or not the filling efficiency is so high that knocking occurs. If knocking efficiency is low, knocking does not occur in the first place. Therefore, using this filling efficiency threshold Itac0, it is determined whether or not knocking may occur.

  In step S5, the controller 70 determines whether or not the filling efficiency Itac is larger than the filling efficiency threshold Itac0. If it is larger, the process proceeds to step S6, and if not, the process proceeds to step S12.

  In step S6, the controller 70 obtains the in-cylinder gas temperature temp_ivo at the intake valve opening timing (IVO). Specifically, the in-cylinder gas temperature temp_ivo is obtained by applying the engine rotational speed Ne and the charging efficiency Itac to a characteristic map shown in FIG.

  In step S7, the controller 70 obtains the residual gas rate resr of the in-cylinder gas. Specifically, the in-cylinder residual gas ratio resr is obtained by applying the engine rotational speed Ne and the charging efficiency Itac to the characteristic map shown in FIG. 6B stored in advance in the ROM, for example.

  In step S8, the controller 70 obtains the in-cylinder gas temperature increase amount delta_temp in the transient state. Specifically, it may be obtained based on the following equation (1).

  Note that temp_ivo_old is the in-cylinder gas temperature at the intake valve opening timing (IVO) one cycle before.

  Here, it supplements about Formula (1). The in-cylinder gas temperature increase amount delta_temp in the transient state can be obtained based on the following equation (2).

  The in-cylinder gas temperature temp_ivc_tra in IVC in the transient state and the in-cylinder gas temperature temp_ivc_cnst in IVC in the steady state can be approximated by the following equations (3-1) and (3-2).

  The residual gas rate resr_tra in the transient state and the residual gas rate resr_cnst in the steady state are substantially the same as shown in FIG. Therefore, it can be approximated by the following equation (4).

  Therefore, equation (2) can be modified as follows.

  This is the above equation (1).

  In step S9, the controller 70 sets the temperature increase threshold value delta_temp0 [K]. Specifically, the temperature increase threshold value delta_temp0 [K] is set by applying the engine rotational speed Ne to a characteristic map shown in FIG. The temperature increase threshold value delta_temp0 is a reference value for determining whether or not the temperature increases as knocking occurs. Since knocking does not occur in the first place if the temperature rise is low, the presence or absence of the possibility of knocking is determined using this temperature rise threshold value delta_temp0.

  In step S10, the controller 70 determines whether or not the gas temperature increase amount delta_temp is larger than the temperature increase threshold value delta_temp0. If it is larger, the process proceeds to step S11, and if not, the process proceeds to step S12.

  In step S11, the controller 70 obtains the ignition timing correction amount adv_ret [degCA]. Specifically, the ignition timing correction amount adv_ret is obtained by applying the gas temperature increase amount delta_temp to, for example, a characteristic map shown in FIG.

  In step S12, the controller 70 sets zero as the ignition timing correction amount adv_ret.

  In step S13, the controller 70 obtains the ignition timing adv [degBTDC]. Specifically, it may be obtained based on the following equation (6).

  According to this embodiment, as shown in FIG. 2 and equation (2), the in-cylinder gas temperature at the predetermined timing during the transient operation of the engine, and the in-cylinder gas in the case of steady operation at the rotational speed and load at that timing The larger the temperature difference from the temperature, the greater the amount of increase in the temperature of the in-cylinder gas. The ignition timing is greatly retarded by determining that knocking is more likely to occur as the amount of increase in the temperature of the in-cylinder gas increases. Since it did in this way, ignition timing can be retarded by an appropriate amount at an appropriate timing, and knocking can be reliably prevented. Further, fuel consumption deterioration and drivability deterioration due to unnecessary correction of the ignition timing can be avoided.

  Further, when the in-cylinder gas temperature rise amount or the engine load (filling efficiency) is smaller than a predetermined value, knocking does not occur in the first place. In such a case, the ignition timing retardation correction is not executed, so that it is possible to avoid deterioration in fuel consumption and drivability due to unnecessary delay correction of the ignition timing.

  The predetermined value is set according to the engine speed. The operation region where knocking occurs during transient operation becomes wider as the engine speed is lower. By taking into account this point and determining a region in which the ignition timing is retarded, it is possible to avoid deterioration in fuel consumption and drivability due to unnecessary delay correction of the ignition timing.

  Further, based on the in-cylinder gas temperature at the intake valve opening timing of the current cycle, the in-cylinder gas temperature at the intake valve opening timing of the previous cycle, and the remaining gas ratio of the current cycle, the temperature of the in-cylinder gas is The amount of increase was calculated. In general, the temperature sensor has poor responsiveness, and it is very difficult to accurately measure the transient temperature without delay. However, according to this embodiment, the amount of change in the cylinder temperature can be easily estimated.

  Further, the in-cylinder gas temperature at the intake valve opening timing is calculated based on the engine rotation speed during the intake stroke and the intake air amount or intake pressure during the intake stroke. Since the cause of knocking is due to the change in the operating state between the front and rear cycles of the same cylinder, the accuracy of the retard timing can be improved by optimizing the object to be compared.

  Without being limited to the embodiments described above, various modifications and changes are possible within the scope of the technical idea, and it is obvious that these are also included in the technical scope of the present invention.

It is a figure which shows one Embodiment of the ignition timing control apparatus of the engine by this invention. It is a figure explaining the fundamental technical idea of the ignition timing control apparatus of the engine by this invention. 4 is a main flowchart for explaining the operation of the engine ignition timing control device according to the present invention. It is a figure which shows an example of the map for setting a basic ignition timing. It is a figure which shows an example of the map for setting a filling efficiency threshold value and a temperature rise threshold value. It is a figure which shows an example of the map for calculating | requiring the in-cylinder gas temperature and charging efficiency in an intake valve opening timing (IVO). It is a figure explaining that the residual gas rate in a transient state and the residual gas rate in a steady state are substantially equal. It is a figure which shows an example of the map for setting an ignition timing correction amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition timing control apparatus 12 Air flow sensor 13 Intake pressure sensor 14 Spark plug 21 Crank angle sensor 70 Controller Step S3 Basic ignition timing calculation means / basic ignition timing calculation step Step S8 In-cylinder gas temperature increase calculation means / in-cylinder gas temperature increase Amount calculation step Steps S11, S12 Correction amount calculation means / correction amount calculation step Step S13 Ignition timing calculation means / Ignition timing calculation step

Claims (12)

Basic ignition timing calculating means for calculating basic ignition timing based on the engine speed and load;
Calculates the amount of increase in the in-cylinder gas temperature according to the temperature difference between the in-cylinder gas temperature at a predetermined timing during transient operation of the engine and the in-cylinder gas temperature in the case of steady operation at the rotation speed and load at that timing. In-cylinder gas temperature rise amount calculating means,
Correction amount calculation means for calculating a correction amount of the ignition timing based on the in-cylinder gas temperature increase amount;
Ignition timing calculating means for calculating an ignition timing during transient operation by retarding the correction amount from the basic ignition timing;
An ignition timing control device for an engine. The gas temperature increase amount calculating means, as the temperature difference between the in-cylinder gas temperature at a predetermined timing during the transient operation of the engine and the in-cylinder gas temperature at the time of steady operation at the rotation speed and load at that timing is larger, Large increase in the temperature of the in-cylinder gas temperature,
The engine ignition timing control device according to claim 1, wherein: The gas temperature increase amount calculating means calculates an increase amount of the temperature of the in-cylinder gas based on a change in charging efficiency during the transient operation of the engine.
The engine ignition timing control device according to claim 1 or 2, wherein the engine ignition timing control device is provided. The gas temperature increase amount calculating means calculates that the temperature of the in-cylinder gas when the charging efficiency of the engine is low is high.
The engine ignition timing control device according to any one of claims 1 to 3, wherein the engine ignition timing control device is provided. The correction amount calculating means calculates the ignition timing correction amount as the in-cylinder gas temperature increase amount increases.
The engine ignition timing control device according to any one of claims 1 to 4, wherein the ignition timing control device for an engine is provided. The correction amount calculation means calculates the ignition timing correction amount as zero when the in-cylinder gas temperature increase amount is smaller than the increase amount threshold value;
The engine ignition timing control device according to any one of claims 1 to 5, wherein the engine ignition timing control device is provided. The increase amount threshold is set based on the engine speed.
The engine ignition timing control device according to claim 6. The correction amount calculation means calculates the correction amount of the ignition timing as zero when the engine load is smaller than a load threshold.
The engine ignition timing control device according to any one of claims 1 to 7, wherein the engine ignition timing control device is provided. The load threshold is set based on the engine speed.
The engine ignition timing control device according to claim 8. The gas temperature increase amount calculation means is based on the in-cylinder gas temperature at the intake valve opening timing of the current cycle, the in-cylinder gas temperature at the intake valve opening timing of the previous cycle, and the remaining gas ratio of the current cycle. Calculating the amount of temperature rise in the cylinder,
The engine ignition timing control device according to any one of claims 1 to 9, wherein the engine ignition timing control device is provided. The in-cylinder gas temperature at the intake valve opening timing is calculated based on the engine rotation speed during the intake stroke and the intake air amount or intake pressure during the intake stroke.
The engine ignition timing control device according to claim 10. A basic ignition timing calculation step for calculating a basic ignition timing based on the engine speed and load;
Calculates the amount of increase in the in-cylinder gas temperature according to the temperature difference between the in-cylinder gas temperature at a predetermined timing during transient operation of the engine and the in-cylinder gas temperature in the case of steady operation at the rotation speed and load at that timing. An in-cylinder gas temperature increase calculation step,
A correction amount calculating step of calculating a correction amount of the ignition timing based on the in-cylinder gas temperature increase amount;
An ignition timing calculation step of calculating an ignition timing during transient operation by retarding the correction amount from the basic ignition timing;
An ignition timing control method for an engine having

Images