JPH0329545Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an intake control device for an internal combustion engine in which one cylinder has a plurality of intake passages and one intake control valve is disposed therein.

[Conventional technology]

2. Description of the Related Art A type of internal combustion engine is known in which a plurality of intake passages are installed in one cylinder, an intake control valve is disposed in one of the intake passages, and the intake control valve is opened and closed according to engine operating conditions. The intake control valve is closed at low engine speeds. At low loads when the amount of intake air is small, the intake air is throttled by closing the intake control valve. On the other hand, the intake control valve is opened when the load is high, and both intake passages are opened. Therefore, high filling efficiency can be obtained.
(See, for example, Japanese Patent Application Laid-Open No. 57-105534.) [Problems to be Solved by the Invention] Conventionally, the set value of the rotational speed for switching the intake control valve from the closed state to the open state is set to about 4000 rpm, for example. However, when comparing the open state and the closed state of the intake control valve, the allowable advance amount of the ignition timing is larger when the intake control valve is open than when it is closed.
Therefore, when so-called regular gasoline with a low octane number is used as fuel at low engine speeds, the permissible advance amount of regular gasoline itself is small, so the intake control valve is closed, and the ignition timing is The degree of advance angle becomes smaller, resulting in problems such as lower fuel consumption and deterioration of engine performance.

Therefore, an object of this invention is to provide a device that can perform optimal control of an intake control valve depending on the octane number of fuel.

[Means for solving problems]

FIG. 1 shows the configuration of this invention, and an internal combustion engine has a plurality of intake passages 1A, 1 in one cylinder 1.
B, and an intake control valve 2 that opens and closes one intake passage 1B. The intake control device of this invention includes an intake control valve driving means 3 connected to the intake control valve 2 and driving the intake control valve 2 between a closed position and an open position, and an intake control valve driving means 3 that detects the octane number of fuel supplied to the engine. Fuel octane number detection means 4, load detection means 5 for detecting engine load, and first gate means (AND) for outputting a first detection signal when a state in which the fuel octane number is high and the engine load is high is detected.
6, a rotation speed detection means 7 which detects a state where the engine rotation speed is high and outputs a second detection signal, and is connected to the first gate means 6 and the rotation speed detection means 7 and outputs the first detection signal or the second detection signal. It consists of a second gate means (OR) 8 which applies a drive signal to the intake control valve drive means 3 so as to open the intake control valve 2 when the signal is applied.

[Effect]

When the rotational speed is high, the second gate means 8 applies a signal to the intake control valve driving means 3, and the intake control valve 2 is opened.

Since the first gate means 6 is not operated when the octane number of the fuel is high, the intake control valve drive means 3 operates the intake control valve 2 when the rotation speed is low regardless of the load.
will be closed.

When the octane number of the fuel is low and the engine load is high, the first gate means is driven, and the second gate means 8 applies a signal to the intake control valve driving means 3 even when the engine speed is low. That is, when the fuel has a low octane number, the intake control valve 2 is opened when the load is large even if the engine speed is low.

〔Example〕

In Figure 2 showing the overall configuration of this invention, 1
0 is the engine body, and 12 indicates one combustion chamber. Two intake ports 14A in the combustion chamber 12
and 14B and two exhaust ports 16A and 16B are provided. The intake ports 14A, 14B are connected to the intake pipe 18, and the intake pipe 18 includes intake passages 18 connected to the intake ports 14A, 14B, respectively.
A and 18B are formed. One intake passage 18A
An intake control valve 20 is installed inside. The intake control valve 20 is of a butterfly type, and a lever 22 is fixed to one end of the valve shaft 21. The lever 22 is connected to a diaphragm actuator 2 via a rod 23.
4. The actuator 24 includes a diaphragm 25 and a spring 26, the spring 26 biasing the diaphragm 25 to the left in the figure, so that the lever 21 is biased so that the intake control valve 20 assumes a fully open position. The diaphragm 25 is switched between a negative pressure source and an atmospheric pressure source by a three-way solenoid valve 27 . That is, when the solenoid valve 27 is in the non-operating state at the white port position, the solenoid valve 27
is communicated with a negative pressure port 30 formed in a surge tank 31 via a negative pressure pipe 28 and a pressure storage tank 29, and the negative pressure acts on the diaphragm 25, so the diaphragm 25 is pulled against the spring 26. ,
The intake control valve 20 is rotationally driven so as to be in a closed state. When the electromagnetic valve 27 is driven, the electromagnetic valve 27 assumes the black port position and is connected to the air filter 19, and atmospheric pressure acts on the diaphragm 25, so that the intake control valve 20 assumes an open state.

Exhaust ports 16A and 16B are connected to exhaust manifold 3
Connected to 4.

Each combustion chamber 12 is provided with an ignition plug 36 and connected to a distributor 38 . The ignition device 40 includes an ignition coil 40a and an ignition circuit 40b. As is well known, the distributor 38 includes a distribution shaft 42 and connects the spark plugs 36 of each cylinder to an ignition device in a predetermined order.

50 is a control circuit for controlling the operation of the intake control valve 20 according to this invention, and is configured as a microcomputer system. Control circuit 5
0 is microprocessing unit (MPU) 5
2, a memory 54, an input port 56, and an output port 58. The input port 58 is connected to crank angle sensors 59 and 60, an air flow meter 61, a knocking sensor 62, and other sensor groups not shown because they are not directly related to this invention.
Crank angle sensors 59 and 60 are provided facing magnet members 63 and 64 on the distributor distribution shaft 42 connected to the crankshaft, and generate pulse signals corresponding to the rotation of the crankshaft. 1st
The crank angle sensor 59 generates a pulse signal every revolution (720° CA) of the engine, and this serves as a reference signal. The second crank angle sensor 60 is
Generates a pulse signal every 30°CA and serves as a rotation speed measurement and interrupt control signal. The air flow meter 61 is installed in the intake pipe upstream of the throttle valve 33, and generates a signal corresponding to the amount of intake air. Also,
The knocking sensor 62 is attached to the engine body 10 and converts mechanical vibrations of the engine into electrical signals. As is well known, the knocking sensor 62 is connected to an integrating circuit 63 and a peak hold circuit 64, and the background level and peak level of the knocking signal are extracted and applied to the input port 56 via a switching circuit 65. As is well known, the presence or absence of knocking is detected by comparing the peak level with the background level.

Output port 58 is connected to ignition circuit 40b. As will be described later, the control circuit 50 calculates the ignition timing based on the signal from the knocking sensor 62.
An ignition signal is applied from output port 58 to ignition circuit 40b. In addition, the output port 58 is connected to the intake control valve 2.
It is connected to the electromagnetic valve 27 for driving No. 0. As will be described later, the control circuit 50 forms a drive signal for the solenoid valve 27 according to the rotation speed, load, and octane number of the fuel.
This drive signal is output from the output port 58.

How the control circuit 50 operates will be explained below with reference to the flowcharts of FIGS. 3 and 4. The program that realizes this operation is in the memory 54.
Needless to say, it is stored in .

FIG. 3 shows an ignition control routine, and this routine is a crank angle interrupt routine executed by detecting the position of the crankshaft before the ignition timing of the cylinder by the crank angle sensors 59 and 60. In step 80, the basic ignition timing _θBASE is calculated from the intake air amount-rotational speed ratio Q/NE and the rotational speed NE, as is well known. A data map of basic ignition timing between Q/NE and NE is provided in the memory 54,
It is well known that a complementary operation is performed.

At step 82, the peak level a and background level b of the signal from the knocking sensor 62 are input. That is, the signal from the knocking sensor changes as shown in FIG. 5B, and reaches its maximum amplitude at a certain crank angle after compression top dead center TDC. A/D conversion of the peak level a and the background level b is performed by the peak hold circuit 64 and the integration circuit 63 in a well-known routine that will not be described. data is stored and this is read.

In step 84, it is determined whether the peak level a is greater than k times the background level b. If the determination is affirmative, it is determined that knocking is present, and the process proceeds to step 86, where the ignition timing retardation correction amount Δθ is incremented by α. If the determination is negative, it is determined that there is no knocking, and the process proceeds from step 84 to step 88, where the retard angle correction amount Δθ is decremented by β. In this way, feedback control is performed to increase or decrease the retard angle correction amount depending on the presence or absence of knocking, and optimal advance angle control is executed within a range where knocking does not occur. At this time, considering the type of fuel, in the case of so-called high-octane gasoline with a high octane number, the retard angle correction amount Δθ will be small because there is a large margin for knocking, whereas in the case of so-called regular gasoline, the retard angle correction amount is small because the margin for knocking is small. The amount Δθ increases. Therefore, by looking at the magnitude of the retardation correction amount Δθ, it is possible to know whether the fuel is high-octane or regular. Incidentally, the detection of the fuel type according to the amount of retardation Δθ of the ignition timing is the same as the method disclosed in Japanese Patent Application Laid-Open No. 157304/1983.

In step 90 of Fig. 3, the basic ignition timing θ _BASE
The ignition timing θ is obtained by subtracting the retardation correction amount Δθ from the ignition timing θ. At step 92, an ignition signal is output from output port 58 to ignition circuit 40b. Therefore, as is well known, the ignition signal falls at an angle θ before the compression top dead center, and ignition is executed. See Figure 5c.

FIG. 4 shows a driving routine for the intake control valve 20, and this routine is a time interrupt routine executed at predetermined time intervals. In step 94, the engine speed NE is set to a predetermined value, for example 4000r.pm.
It is determined whether the (In addition, the rotation speed NE
As is well known, the signal from the second crank angle sensor 64 is
It can be calculated using the time interval of the 30° CA signal. ) When the rotational speed NE is higher than 4000r.pm, proceed from step 94 to step 95, and output port 5
8, a High signal is applied to the solenoid valve 27, the solenoid valve 27 assumes the black position, and the diaphragm 2
Since atmospheric pressure acts on 5, the intake control valve 20 is opened by the spring 26. Therefore, the intake passage 8
Air is supplied through the intake ports A, 18B and the intake ports 14A, 14B.

When the rotational speed NE is lower than 4000 rpm, the process proceeds from step 94 to step 96, where it is determined whether the ignition timing retardation correction amount Δθ is larger than a predetermined value, for example, 7°. When Δθ<7°, it is determined that high octane gasoline is being used. In this case, the next step 97 is bypassed and the process proceeds to step 98, where the low signal is output from the output port 58 to the solenoid valve 27.
is applied to Therefore, the solenoid valve 27 assumes the white port position, and negative pressure acts on the diaphragm 25, so the intake control valve 20 is closed. Thus, air is supplied only through the intake passage 18B and the intake port 14B, but not through the intake passage 18A and the intake port 14A.

When the ignition timing retardation correction amount Δθ>7°, it is determined that gasoline with a low octane number is being used, and the flow proceeds from step 96 to step 97, where the intake air amount-rotational speed ratio Q/NE is set to a predetermined value, for example 0.65. /rev
It is determined whether the The intake air amount-rotation speed ratio is a value equivalent to the engine load. Therefore, other load-equivalent factors such as intake pipe negative pressure can be used for load determination. When Q/NE<0.65, it is determined that the load is low, and the flow proceeds from step 97 to step 98, where the intake control valve 20 is closed.
When Q/NE≧0.65, it is determined that the load is high, and the process proceeds from step 97 to step 95. That is, when the load is high, the intake control valve 20 is controlled to be opened even if the engine speed is lower than 4000 rpm.

FIG. 6 is a diagram explaining the operating range of the intake control valve 20 in this invention. When using gasoline with a high octane number, it is controlled only by the rotation speed as shown in A, and when the rotation speed is 4000 rpm or more, the intake air is The control valve opens and closes when the control valve opens. On the other hand, in the case of gasoline with a low octane number, Q/NE
Due to these factors, the intake control valve 20 is opened when the load is high (Q/NE≧0.65 l/rev) even if the rotational speed NE is lower than 4000 rpm. The reason for controlling in this way will be explained next. Comparing the closed state and the open state of the intake control valve 20, the amount of advance must be reduced by 8-10 degrees in the closed state compared to the open state.
On the other hand, when comparing regular gasoline and high-octane gasoline, regular gasoline has about 8 degrees less advance margin than high-octane gasoline. Therefore, in the conventional system, when regular gasoline was used, there was a problem in that the lack of advance margin due to the closing of the intake control valve combined with the fact that the advance amount became extremely small and performance deteriorated. With this idea, when using regular gasoline,
In the low rotation speed range, as long as the load is high, the intake control valve 20
Since the is closed, the angle can be advanced accordingly, and the degree of advance can be made almost the same for regular gasoline and high-octane gasoline. As shown in Fig. 7, when the intake control valve is opened at low speed, Q/
Although the NE is slightly reduced, this loss is more than compensated for by the benefit obtained from being able to advance the ignition timing, and overall engine performance can be improved.

[Effect of idea]

According to this invention, when using fuel with a low octane number, even if the engine speed is low, if the engine is under high load, the intake control valve is opened to adjust the ignition timing to the same level as when using fuel with a high octane number. The intake control valve can be advanced to a maximum of 100 degrees, making it possible to obtain high engine performance that outweighs the adverse effects of closing the intake control valve.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the configuration of this invention, Figure 2 is a diagram showing the overall configuration of the embodiment, Figures 3 and 4 are flowcharts explaining the operation of the control circuit, and Figure 5 is ignition timing control. Figure 6 is a diagram explaining the timing of intake control valve control in this invention using A for gasoline with a high octane number and B for gasoline with a low octane number. Intake air amount - rotation speed ratio Q/NE
A graph explaining the change in rotation speed NE over time. 12... Combustion chamber, 14A, 14B... Intake port, 18A, 18B... Intake passage, 20... Intake control valve, 24... Actuator, 27... Solenoid valve, 36... Spark plug, 38... Day Triviewer, 40... Ignition device, 50... Control circuit, 5
9, 60...Crank angle sensor, 61...Air flow meter, 62...Knocking sensor.

Claims (1)

[Scope of Claim for Utility Model Registration] In an internal combustion engine that has a plurality of intake passages in one cylinder and an intake control valve that opens and closes one of the intake passages, the intake control valve is connected to the intake control valve in the closed position. and an open position; a fuel octane number detection means for detecting the octane number of fuel supplied to the engine; a load detection means for detecting the engine load; a gate means that outputs a first detection signal when detecting a high state of engine speed; a rotation speed detection means that detects a high engine speed state and outputs a second detection signal; connected to the gate means and the rotation speed detection means; An intake control device for an internal combustion engine, comprising a second gate means for applying a drive signal to an intake control valve drive means so as to open the intake control valve when a first detection signal or a second detection signal is received.