JPH0716044Y2 - Engine ignition timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an ignition timing control device for electronically controlling the ignition timing of an engine, and more particularly to an ignition timing correction method for recirculating exhaust gas.

[Prior Art] Conventionally, an ignition timing control device which calculates an ignition timing of an engine from an engine speed indicating an operating state of the engine, an intake negative pressure and the like is well known (Japanese Patent Laid-Open No. 57-193).
771 publication).

As a method for calculating the ignition timing, the ignition timing corresponding to the operating state designated by the combination of the engine speed and the intake negative pressure is stored in a memory as a map, and the actual ignition timing is calculated from the map during the actual operation. A map method of reading is known.

By the way, the factors that control the ignition timing of the engine include many factors such as the engine cooling water temperature and the intake temperature in addition to the above-described rotational speed and intake negative pressure. A so-called EG that recirculates part of the exhaust gas to the intake system of the engine as an inert gas component
The exhaust gas recirculation amount (EGR amount) at the time of R is also one of the above factors, and it is necessary to correct the ignition timing according to the exhaust gas recirculation amount.

A map for correction may be used to perform the ignition timing correction (hereinafter referred to as EGR correction for simplification) accompanying exhaust gas recirculation, but having a detailed map in memory greatly increases the memory capacity. Leading up to
Not preferred. Therefore, in order to reduce the memory capacity, it is known that a simple map is used to perform a simple correction.

With this, the ignition timing may not be corrected correctly. This will be specifically described with reference to FIG.
Now, the operating state of the engine is changed, the target EGR amount is determined accordingly, and the EGR correction target value θ′EGR of the ignition timing is significantly increased according to this target EGR amount, as shown in the bottom of the figure. If changed, as indicated by the solid line B in the upper part of the figure,
In the conventional map control, the ignition timing is largely corrected corresponding to θ'EGR.

However, as shown in the middle of the figure, the actual EGR amount VEGR
Is reached with a certain delay due to the response delay of the EGR control system, etc. Therefore, between the ignition timing A originally set according to the actual EGR amount VEGR and the corrected ignition timing B. In this case, a large deviation occurs, which causes knocking when the deviation is on the delay side, and output hesitation when the deviation is on the advance side.

[Object of the Invention] An object of the present invention is to provide an ignition timing control device for an engine which can relatively accurately perform EGR correction of the ignition timing even when a coarse map is used.

Therefore, according to the present invention, an exhaust gas recirculation passage is provided, and an exhaust gas recirculation control valve for controlling the exhaust gas recirculation amount according to the operating state of the engine is provided in the recirculation passage, while the exhaust gas recirculation valve is provided. An engine ignition timing control device for correcting a basic ignition timing according to a flow rate, comprising an exhaust gas recirculation control valve position sensor, the exhaust gas recirculation control valve being determined according to an output of the sensor and an engine operating state. The ratio of the current exhaust gas recirculation amount to the target exhaust gas recirculation amount is calculated from the target position and the target engine position based on the ignition timing correction target value determined from the correction map according to the target position and the target position. Set the ignition timing correction amount for the basic ignition timing that is determined according to the operating state. Ignition of an engine provided with an ignition timing correction means for correcting the ignition timing accompanying exhaust gas recirculation so that the ignition timing correction amount is set small and gradually approaches the ignition timing correction target value. A timing control device is provided.

[Advantage of the Invention] According to the present invention, the target E determined according to the current EGR amount detected by the position sensor and the operating state of the engine.
Based on the ratio with the GR amount, the ignition timing correction target value determined by the correction map corresponding to the target EGR amount is corrected before setting the ignition timing, so the ignition timing correction target value is set roughly on the map. However, the ignition timing can be set according to the actual EGR state, and accurate ignition timing correction can be performed without increasing the memory capacity of the correction map.

Further, in the present invention, when the difference between the target EGR amount and the current EGR amount is large, the correction amount is set to be smaller than when it is small, and the target value is gradually approached. The deterioration can be prevented, and the ignition advance control can be stabilized.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, with respect to the spark plug 3 provided so as to face the combustion chamber 2 of the engine 1, a drive circuit 4 for driving the spark plug 3 and an ignition timing control circuit 5 for controlling the drive circuit 4 are provided. Is provided. The ignition timing control circuit 5 is composed of a microcomputer, and an intake air intake amount detected by an air flow meter 8 provided in an intake passage 7 downstream of the air cleaner 6 and a throttle valve 9 provided downstream of the air flow meter 8 are compared. Throttle opening detected by the throttle opening sensor 10 provided in the negative pressure sensor provided in the surge tank 11 provided downstream of the throttle valve 9.
Intake negative pressure detected by 12, engine speed sensor 13, intake air temperature sensor 14, cooling water temperature sensor 15, each output of ignition switch IgSW, and pickup provided for the engine output shaft (not shown) The ignition timing is set by executing the control flow shown in FIG. 1 with the output of the crank angle sensor 16 of the type and the output of the position sensor 19 of the EGR control valve 18 provided in the EGR passage 17 as inputs.

The ignition timing setting method executed by the ignition timing control circuit 5 will be described below with reference to the flowchart of FIG.

The control is started, the system is initialized in step 101, it is determined in step 102 whether the engine can be started, and when the engine is started, the engine speed, the intake negative pressure, the cooling water temperature, the intake temperature Is read in step 103.

Next, at step 104, the basic advance angle amount θBSE is calculated from the built-in ignition timing setting basic map based on the various amounts corresponding to the engine operating condition read at step 103. Then, in step 105, it is determined whether or not exhaust gas recirculation is in progress, and when it is during EGR, in step 106 the EGR correction target value θ'EGR of the ignition timing corresponding to the target EGR amount determined according to the current operating state. Is read as a target value from the EGR correction map. This EGR correction map is a coarse-grained map, and the memory capacity required for this map is small. Next, at step 107, the EGR control valve 1 installed in the exhaust gas recirculation passage 17 (see FIG. 2).
The output of the position sensor 19 provided for 8 is read to read the current opening degree of the EGR control valve 18. That is, the current EGR amount is calculated from the opening degree of the EGR control valve 18.

In the next step 108, the current EG calculated in step 107
From the ratio of the R amount and the target EGR amount, that is, the optimum EGR amount that should be set corresponding to the operating state of the engine, that is, the target EGR amount, the EGR corrected advance amount θEGR of this time is calculated by the following formula.

θEGR = θ′EGR × (current EGR amount / target EGR amount) That is, in this calculation, the EGR correction target value θ′EGR determined from the EGR correction map according to the target EGR amount is corrected by the current EGR amount. The correction amount of this EGR correction target value θ′EGR is
It is determined by the ratio of the current EGR amount and the target EGR amount. When this ratio is small, that is, when the difference between the two is large, it is small, and when the difference between the two is small, it is large. This is based on the EGR correction advance amount θEGR that is actually set.
EGR when the difference between the amount and the target EGR amount is large (at the initial time when the operating state is changed and as a result, the target EGR amount is changed)
The correction advance angle amount θEGR is changed by a slight amount, and abrupt change is avoided.

FIG. 3 shows this situation. When the opening of the EGR control valve 18 changes in the decreasing direction like E ₁ , E ₂ and E ₃ , EGR
The corrected advance angle amount θEGR changes like θ ₁ , θ ₂ , and θ ₃ at a change ratio that corresponds one-to-one with the change in the opening degree of the EGR control valve 18. Similarly, when the EGR control valve 18 is changed in the increasing direction like E ₄ , E ₅ , and E ₆ , the EGR correction advance amount θEGR is corresponding to θ ₄ ,
Like θ ₅ and θ ₆ , they are changed in a one-to-one correspondence with changes in the opening of the EGR control valve 18. For this reason, the excessive advance or excessive delay of the ignition timing as shown by the solid line B in FIG. 4 is surely eliminated, and as shown by the dotted line A in FIG. 4 without causing knocking or hesitation, The ignition timing can be corrected by accurately following the required value corresponding to the operating state.

In the next step 109, the water temperature correction advance amount θWL is calculated, and in step 110, the intake temperature correction advance amount θAL is calculated,
In step 111, the basic advance angle θ calculated in step 104
EGR calculated in steps 108, 109 and 110 for BSE
The correction advance angle amount θEGR, the water temperature correction advance angle amount θWL, and the intake air temperature correction advance angle amount θAL are added to finally obtain the ignition advance amount θK. In step 112, the energization time to the igniter is calculated from the ignition advance amount θK calculated in step 111, and at the end of this energization time, the ignition plug 3 is driven to ignite. After the calculation of the energization time, various flags are checked in step 113, and then the process returns to step 103 again.

If EGR is not being performed, steps 105 to 106, 107 and 108 are skipped and EG is executed in step 114.
Step 10 after setting the R correction advance angle θEGR to “0”
Go to 9 and perform only water temperature correction and intake air temperature correction.

As described above, in the present invention, the target EGR correction advance amount θ′EGR determined based on the coarsely set ignition correction map is set.
Is corrected by following the degree of change in the EGR amount, and then the actual E
Since the GR correction advance amount θEGR is set, the EGR correction of the ignition timing accurately corresponds to the EGR state at that time.

[Brief description of drawings]

FIG. 1 is a flow chart of control executed by an ignition timing control circuit according to the present invention, FIG. 2 is a system configuration diagram of an engine ignition timing control device according to the present invention, and FIG. 3 is a control system according to the present invention. FIG. 4 is an explanatory diagram showing the state of EGR correction of the obtained ignition timing, and FIG. 4 is an explanatory diagram showing the state of EGR correction in the conventional ignition timing control. 1 ... Engine, 3 ... Spark plug, 4 ... Drive circuit,
5 ... Ignition timing control circuit, 17 ... EGR passage, 18 ... EGR control valve, 19 ... Position sensor.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masahiko Matsuura, 3-1, Shinchi Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Co., Ltd. (72) Makoto Hotate, 3-1-1 Shinchu, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (56) Reference JP-A-54-84108 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. An exhaust gas recirculation passage is provided, and an exhaust gas recirculation control valve for controlling the exhaust gas recirculation amount according to the operating state of the engine is provided in the recirculation passage, while basic ignition is performed according to the exhaust gas recirculation amount. In an engine ignition timing control device for correcting the timing, an exhaust gas recirculation control valve position sensor is provided, and the present position is determined from the output of the sensor and the target position of the exhaust gas recirculation control valve that is determined according to the operating state of the engine. The ratio of the exhaust gas recirculation amount to the target exhaust gas recirculation amount is calculated, and it is determined according to the current operating state of the engine based on this ratio and the ignition timing correction target value determined from the correction map according to the target position. Set the ignition timing correction amount for the basic ignition timing, and when the above ratio is large,
Ignition timing correction means for correcting the ignition timing accompanying exhaust gas recirculation is provided so that the ignition timing correction amount is set smaller than when it is small and gradually approaches the ignition timing correction target value. An ignition timing control device for an engine.