JPH02191871A - Start time ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve startability in the time of very low temperature by setting ignition timing of fixed value, when an internal combustion engine is in starting further with the engine in a low temperature condition and when an engine speed is in not more than a predetermined engine speed, and the ignition timing in an advance timing side from the fixed value when the engine speed is larger than the predetermined engine speed. CONSTITUTION:An internal combustion engine M1 is detected for its start by a start detecting means M2, when an engine low temperature condition is detected by a low temperature detecting means M5 and when a speed of the engine M1 is decided to be in not more than a predetermined engine speed in an engine speed decision means M4, ignition timing of fixed value is set by an ignition timing setting means M6. While, when the speed of the engine M1 is decided to be larger than the predetermined engine speed, the ignition timing in an advance timing side from the fixed value is set by the setting means M6. Accordingly, even when the speed of the engine M1 obtains a very low speed in the time of very low temperature of the engine M1 and even when initial explosion occurs in this time, no excessive advance timing is generated of the ignition timing based on a time delay, while when the engine speed in start time is relatively high, the engine is started by large torque.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing control device at the time of starting an internal combustion engine, which controls ignition timing at the time of starting the internal combustion engine.

[Prior Art] Conventionally, the operating state of an internal combustion engine is detected based on the rotational speed of the internal combustion engine detected from a distributor, the amount of intake air detected from an air flow meter, etc., and the optimal ignition timing is determined according to the operating state. Ignition timing control devices that determine ignition timing are known. In this system, ignition timing data corresponding to the operating state is prepared in advance, the ignition timing to be controlled is read based on the detected operating state, and the output signal is supplied to the power transistor of the ignition device, etc. .

When starting the internal combustion engine, the ignition timing data is not used, and the ignition timing is fixed at the initial set angle of the distributor.

By the way, if the initial set angle is fixed near top dead center, the first detonation can be achieved quickly, but the torque during continuous detonation is not sufficient, so it takes time to reach a complete detonation, especially at low temperatures. In this case, as shown in FIG. 6, the viscosity of the oil in the internal combustion engine increases, and as a result, a large torque is required to completely explode the internal combustion engine, which further deteriorates startability.

In addition, even if you try to obtain torque during continuous firing by setting the above initial set angle in advance of the vicinity of top dead center, the battery capacity will decrease at low temperatures because the battery uses chemical changes. decreases, and the rotational speed at startup is 1100r
As a result, combustion is completed before reaching top dead center after ignition, resulting in premature ignition.As a result, even if ignition occurs, it does not generate torque to rotate the internal combustion engine, but rather increases the internal combustion The torque causes the engine to reverse, causing a so-called starter lock phenomenon, which deteriorates starting performance.

Therefore, in order to improve the startability at low temperatures, a method has been proposed in which when the rotational speed is lower than a predetermined value at the time of starting, the advance amount is gradually increased as the rotational speed increases. (``Start-up ignition timing control device'' described in JP-A-55-137359),! II. As shown in Fig. 7, when the rotational speed of the internal combustion engine is 0, the advance angle is set to 1fJiO, and as the rotational speed increases, the advance angle is gradually increased to increase the rotational speed. When the advance angle amount exceeds the predetermined value N1, the advance angle amount is set to a constant value.

[Problems to be Solved by the Invention] However, even with such conventional devices, startability cannot be sufficiently improved when the temperature of the internal combustion engine becomes extremely low.

This is because when the first explosion occurs at extremely low temperatures, when the temperature of the internal combustion engine is extremely low, a rapid increase in rotational speed will occur temporarily, as shown in Figure 8. (If not, the rate of increase in rotational speed is small.) If the ignition timing advance is calculated when the rotational speed increases (for example, at time a), the ignition timing will actually advance based on the advance angle calculation. Since there is a timing delay until the ignition timing is ignited, the ignition timing is controlled to the advanced ignition timing at the point where the rotational speed decreases (for example, at time b). For this reason, the ignition timing at the time when the rotation speed decreases is advanced from the optimal value, resulting in premature ignition.As a result, even if the ignition ignites, it does not generate torque to rotate the internal combustion engine, but rather causes the internal combustion engine to rotate. This caused the problem of starter locking due to the torque that caused the engine to reverse.

The present invention has been made in view of these problems, and is an internal combustion engine that prevents the occurrence of starter lock phenomenon and improves startability when starting at extremely low temperatures, when the temperature of the internal combustion engine is extremely low. An object of the present invention is to provide a starting ignition timing control device.

[Means for Solving the Problems] In order to achieve the above object, the present invention has adopted the configuration shown below as a means for solving the problems. That is, the starting ignition timing control device for an internal combustion engine of the present invention, as illustrated in FIG. Means M
3, and a rotational speed determination means M for determining whether the rotational speed detected by the rotational speed detection means M3 is below a predetermined rotational speed.
4, a low temperature detection means M5 for detecting an engine low temperature state in which the temperature of the internal combustion engine M1 is below a predetermined temperature, and the start detection means M2.
When the start of the internal combustion engine fsffM1 is detected and the engine low temperature state is detected by the low temperature detection means M5, and the rotation speed is determined to be below the predetermined rotation speed by the rotation speed determination means M4, the ignition timing is set to a constant value. In addition to setting
The special effects include: ignition timing setting means M6 for setting ignition timing on the advanced side than the constant value when the rotational speed determining means M4 determines that the rotational speed is higher than the predetermined rotational speed. .

Here, the predetermined rotational speed used for determining the rotational speed by the ignition timing setting means M6 is a value slightly higher than the rotational speed obtained by the first explosion at the time of starting the internal combustion engine M1.

[Operation] In the internal combustion engine starting ignition timing control device of the present invention configured as described above, the starting of the internal combustion engine is detected by the starting detecting means M2, and the low temperature state of the engine is detected by the low temperature detecting means M5. At times, when the rotational speed determination means M4 determines that the rotational speed of the internal combustion engine M1 is less than or equal to a predetermined rotational speed, the ignition timing setting means M6 sets the ignition timing to a constant value, and also detects the starting of the internal combustion engine M1. When the engine low temperature state is detected, if the rotational speed determination means M4 determines that the rotational speed is higher than the predetermined rotational speed, the ignition timing setting means M6 sets the ignition timing to be more advanced than the certain value. is set.

Therefore, when the internal combustion engine M1 is at an extremely low temperature, the internal combustion engine M1
Even if the rotational speed at the time of starting becomes extremely low, the ignition timing remains constant, and as a result, even if the first explosion occurs at that extremely low rotational speed, the ignition timing will remain constant even if the engine starts at an extremely low rotational speed. There is no possibility that the ignition timing will be over-advanced due to timing delay as described in .

Further, when the internal combustion engine M1 is at an extremely low temperature and the rotation speed at the time of starting the internal combustion engine M1 is relatively high, the ignition timing becomes a value on the advanced side of the constant value, and starting is performed with a large torque.

[Example code] Next, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic configuration diagram showing an automobile engine and its peripheral devices equipped with a starting ignition timing control device according to an embodiment of the present invention.

As shown in the figure, the engine 1 is equipped with a spark plug 3 that ignites the fuel in the combustion chamber 2, a water temperature sensor 4 that detects the cooling water temperature of the engine 1, and the like. A throttle valve 6 whose opening degree is adjusted according to the amount of depression of the accelerator pedal, a fuel injection valve 8 which injects fuel into the intake pipe 5, and the like are installed. Further, an oxygen sensor 10 and the like are attached to the exhaust pipe 9 of the engine 1 to detect the oxygen concentration in the exhaust gas.

The opening degree of the throttle valve 6 is detected by a throttle position sensor 11, and the pressure of intake air inside the intake pipe 5 is detected by a vacuum sensor 13 attached to a surge tank 12.

Further, the high voltage generated by the igniter 140 is distributed and supplied to the spark plug 3 via a distributor 15, and the distributor 15 is provided with a rotation speed sensor 16 for detecting the rotation speed of the engine 10.

Detection signals from each of the sensors are input to the electronic control unit 30 and used to control ignition timing and fuel injection amount. Further, the electronic control device 30 receives a signal indicating the rotational state of the starter from a starter motor 35, which is a starting device for the engine 1.

The electronic control device 30 includes a well-known CPU 30a and a ROM 30.
b, RAM 30c, etc., and the input circuit 30
d, output circuit M30e, etc. are connected to each other by a bus 30f as a logic operation circuit. The input circuit 30d includes the various sensors and starter motor 35.
is connected to the output circuit 30e, and the aforementioned fuel injection valve 8, igniter 14, etc. are connected to the output circuit 30e.

Note that 36 is a battery, which is connected to the electronic control unit 30 through the ignition switch 37. starter motor 3
5. Power is supplied to the igniter 14 and the like.

In the electronic control device 30 configured as described above, well-known fuel injection control and ignition timing control are executed based on detection signals from the sensors and the starter motor 35. Ignition timing control, which is the main process related to the invention, will be explained.

FIG. 3 is a flowchart showing the ignition timing calculation process.

This process is repeatedly executed by the electronic control unit 30 while the engine 1 is running. When the process is started, the stem 100 is first executed, and the rotational speed sensor 16. The rotation speed NE of the engine 1 is determined from the detection results of the vacuum sensor 13 and the water temperature sensor 4.

Calculate intake pipe pressure PM and cooling water temperature THW.

Next, in step 110, it is determined whether the engine 1 is currently in the starting state based on whether the starter motor 35 is in the ON state, and it is determined that the starter motor 35 is in the OFF state, that is, the engine 1 is not in the starting state. Then step 12
Transition to 0. In step 120, a well-known ignition timing calculation process is executed to calculate the ignition timing 5PARK using a preset map based on the rotational speed NE and intake pipe pressure PM calculated in step 100, and then -
The process ends once.

On the other hand, in step 110, the starter motor 35 is
When it is determined that the engine 1 is in the N state, that is, the engine 1 is at the time of starting, the process moves to step 130, and the cooling water temperature T calculated in step 100 is checked to determine whether the engine 1 is currently at an extremely low temperature.
The determination is made based on whether the HW is below a predetermined temperature (-20° C. in this embodiment). Here, when it is determined that the cooling water temperature THW is below 120 degrees Celsius, that is, the engine 1 is at an extremely low temperature,
The process moves to step 140, and the rotational speed NE calculated in step 1oo is set to a predetermined rotational speed (in the case of this embodiment, 20
Orpm) or less.

If it is determined in step 140 that the rotational speed NE is 200 rpm or less, the process moves to step 150, and the ignition timing 5
PARK 5 crank angles before top dead center (BTDC5℃A)
Execute the process to set the value, and then end the process on -d.

On the other hand, in step 130 it is determined that the engine 1 is at an extremely low temperature, and in step 140 the rotational speed NE is set to 200.
If it is determined that the rotational speed NE is larger than the rpm, the process proceeds to step 160, and an ignition timing calculation process is executed to increase the advance amount of the ignition timing 5PARK in accordance with the increase in the rotational speed NE calculated in step 100. In detail, the ignition timing 5PARK is calculated using a map as shown in Figure 4.
According to this map, the value of IJIS P ARK at the time of ignition is BTD 05°C when the rotational speed NE exceeds 200 rpm, and the advance amount is gradually increased as the rotational speed NE increases. Furthermore, it becomes constant after a predetermined rotation. After executing step 180, the process ends.

Note that even if it is determined in step 130 that the cooling water temperature THW is higher than 120° C., that is, the engine 1 is not at an extremely low temperature, the above-described step 150 C: fJ line L is performed and the ignition timing 5PARKfi-BTDC5'CA Execute the process to set the value, and then end the process on -d.

According to the ignition timing calculation process configured in this way, when the engine 1 is started and is at an extremely low temperature, the ignition timing is determined when the rotational speed NE of the engine 1 is 200 rpm or less, as shown in FIG. When the rotational speed NE becomes larger than 20 Orpm, the amount of advance becomes B1'' D C5℃A.
It is gradually increased from TDC5°C.

Therefore, according to this embodiment, when the engine 1 is at an extremely low temperature, the rotational speed NE at the time of starting the engine 1 is extremely low (2
0Orpm or less), the ignition timing is BTDC5℃.
Therefore, even if the first explosion occurs at extremely low rpm, the ignition timing will not be over-advanced, even if there is a delay in the actual ignition timing, and as a result, the starter lock will not occur. It is possible to prevent the phenomenon from occurring and improve starting performance. Also, when the engine 1 is at an extremely low temperature and the rotational speed NE at startup is relatively high (greater than 20 rpm), the ignition timing will be a value on the advanced side than the BTDC 5°C, and the ignition timing will be set to a value that is more advanced than the BTDC of 5°C, which is suitable for the high rotational speed NE. Starting is performed at the ignition timing, improving startability. In particular, in this embodiment, when the rotational speed NE becomes larger than 200 m or more, the amount of advance of the ignition timing is gradually increased in accordance with the increase in the rotational speed NE. It is possible to impose an ignition timing suitable for the engine, further improving startability.

In addition, in the above embodiment, when the engine 1 is started at an extremely low temperature, when the rotational speed NE becomes larger than 20 Orpm,
As the rotational speed NE increases, the ignition timing advances B.
It was configured so that the ignition timing was gradually increased from TDC5℃, but instead of this, the ignition timing was changed to
The BTDC 5℃ A clay (rotational speed NE is 200 rp)
It may be configured to set a larger constant value on the advance side than the constant value when the angle is less than or equal to m, for example, BTDCIO°CA.

Further, in the above embodiment, the amount of advance of the ignition timing is set to a constant value BT.
The switching value of the rotational speed NE, which switches from DC5℃A to a value that increases according to the engine rotational speed NE, is set to 200 "0".
Although the switching value is configured to take a constant value m, instead of this, the switching value may be configured to be variable depending on the cooling water temperature THW. That is, at extremely low temperatures, oil viscosity increases and the temporary increase in rotational speed at the first explosion shifts to the lower rotational speed side, so the switching value is controlled to the lower rotational speed side as the cooling water temperature THW is lower. As a result, the amount of advance is increased in accordance with the increase in rotational speed NE from an early stage, and control in a state of large torque becomes possible from an early stage, thereby improving startability. can be increased.

Further, in the above embodiment, the ignition timing is determined based on the engine rotational speed NE and the intake pipe pressure PM, but instead of this, the engine rotational speed NE The ignition timing is determined based on the amount of intake air detected by the air flow meter.
It may be adopted and configured in a J-type engine.

[Effects of the Invention] As detailed above, the internal combustion engine starting ignition timing control device of the present invention can prevent the occurrence of starter lock phenomenon during starting at extremely low temperatures when the temperature of the internal combustion engine is extremely low. It has excellent startability.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the basic configuration of the present invention;
Fig. 2 is a schematic configuration diagram showing an automobile engine equipped with a starting ignition timing control device and its peripheral equipment, which is an embodiment of the present invention, and Fig. 3 is an ignition timing calculation executed by the electronic control circuit. Flowchart showing the process, Figure 4 is a graph showing the map used to execute the process, Figure 5 is a graph showing the trend of ignition timing during cryogenic start calculated by the process, Figure 6 is the engine graph. A graph showing the relationship between temperature and oil viscosity, FIG. 7 is a graph showing the relationship between rotational speed and advance angle amount in the conventional technology,
FIG. 8 is a graph showing problems with the prior art. Ml...Internal combustion engine M2...Start detection means M
3...Rotational speed detection means M4...1 Rotational speed determination means M5...Low temperature detection means M6...Ignition timing setting means 1...Engine 4...Water temperature sensor 1 16...Rotational speed sensor 30...Electronic control unit 3...Spark plug 3...Vacuum sensor

Claims (1)

[Scope of Claims] Start detection means for detecting the start of the internal combustion engine; rotation speed detection means for detecting the rotation speed of the internal combustion engine; and the rotation speed detected by the rotation speed detection means is less than or equal to a predetermined rotation speed. a low temperature detection means for detecting an engine low temperature state in which the temperature of the internal combustion engine is below a predetermined temperature; and a low temperature detection means for detecting a start of the internal combustion engine by the start detection means, When an engine low temperature condition is detected by the means,
When the rotational speed determination means determines that the rotational speed is less than or equal to the predetermined rotational speed, the ignition timing is set to a constant value, and when the rotational speed determination means determines that the rotational speed is greater than the predetermined rotational speed, the ignition timing is set to the constant value. A starting ignition timing control device for an internal combustion engine, comprising: ignition timing setting means for setting ignition timing on the advanced side of the ignition timing value.