JPS6132148Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder internal combustion engine for a vehicle, and particularly to an ignition timing control device thereof.

Conventionally, in a multi-cylinder internal combustion engine, each cylinder is provided with two intake passages, one intake port of the intake passage is provided with a first intake valve that is normally opened and closed, and the other intake port of the intake passage is provided with a hydraulic valve. A second intake valve is provided that is deactivated in the low-speed operating range by a type valve operation stop mechanism, and only the first intake valve is operated in the low-speed operating range to increase the flow velocity of intake air and strengthen the swirl in the combustion chamber. It has been proposed to improve combustion by promoting fuel atomization, and to operate both intake valves in high-speed operating ranges to reduce intake resistance and increase charging efficiency, thereby increasing output.

By the way, in this type of multi-cylinder internal combustion engine, especially in high-load operating conditions, the higher the engine temperature, the more the ignition timing when the second intake valve is not operating is changed to the ignition timing when both the first and second intake valves are operating. If it is not delayed, knocking will occur in the low speed and high load range.

However, in conventional multi-cylinder internal combustion engines of this type, the optimum ignition is achieved depending on the engine temperature, especially in high-load operating conditions, when the second intake valve is not operating and when both the first and second intake valves are operating. Since the timing is not adjusted, there are problems such as knocking in low-speed, high-load ranges, malfunctions depending on engine temperature, and insufficient output.

The present invention is an attempt to solve such problems, and is to adjust the ignition timing when the second intake valve is not in operation to the first and second intake valves according to the engine temperature in the high-load operating state of the internal combustion engine. An object of the present invention is to provide an ignition timing control device for a multi-cylinder internal combustion engine for a vehicle, which prevents knocking and obtains sufficient output by retarding the ignition timing during both operations. shall be.

Therefore, the device of the present invention has a mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner and has a mixture throttle valve inside, and a mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner. A secondary air intake passage which is supplied with air and has a secondary air throttle valve therein is connected to each cylinder of the internal combustion engine, and the secondary air intake passage has a larger cross-sectional area than the air-fuel mixture intake passage. A first intake valve that is normally opened and closed is provided at the intake port at the portion where the air-fuel mixture intake passage connects to the cylinder, and the secondary air intake passage connects to the cylinder. In a multi-cylinder internal combustion engine for a vehicle, in which a second intake valve is installed in the intake port of a portion of the engine and is activated or deactivated by a valve operation/stop mechanism depending on the operating state of the internal combustion engine, the engine temperature of the internal combustion engine can be controlled. A temperature sensor for detecting a load state of the internal combustion engine and a load sensor for detecting a load state of the internal combustion engine are provided, and the ignition timing when the second intake valve is not operated is adjusted according to the engine temperature in a high load operating state of the internal combustion engine. An ignition timing control circuit connected to the temperature sensor and the load sensor is provided to retard the ignition timing when both the first intake valve and the second intake valve are activated. There is.

An ignition timing control device for a multi-cylinder internal combustion engine for vehicles as an embodiment of the present invention will be explained below with reference to the drawings. Fig. 1 is a plan view of an engine equipped with this device, and Fig. 2 is a plan view of an engine equipped with this device. A schematic cross-sectional view of the engine, Figures 3 and 4 are electric circuit diagrams showing its main parts, Figure 5 is a graph showing the relationship between the rotational speed and output of the internal combustion engine, and Figure 6 is a graph showing the relationship between the engine's water temperature and Graphs showing the relationship with the retard amount, FIGS. 7a to 7f, are all waveform diagrams for explaining the effect.

1 and 2, a multi-cylinder internal combustion engine 10 has a cylinder head 12 and a cylinder block 1.
4, and a plurality of combustion chambers 18 are formed in which pistons 16 connected to a crankshaft (not shown) are disposed.

A first intake port 20 having a relatively small cross-sectional area and a second intake port 22 having a larger cross-sectional area are communicated with each combustion chamber 18, and are connected to each other by a first intake valve 24 and a second intake valve 26, respectively. Opening/closing is controlled.

The first and second intake ports 20, 22 extend from opposite sides of the cylinder head 12 and are opposed to each other.
The combustion chamber is opened at a position substantially diagonally with respect to the combustion chamber 18 to generate a swirl in the same direction in the intake air supplied into the combustion chamber 18 through both intake ports 20 and 22. .

Further, an exhaust port 28 is opened in the combustion chamber 18 and extends from the same side of the cylinder head 12 as the first intake port 20, substantially parallel to the intake port.The exhaust port 28 is opened by an exhaust valve (not shown). It is opened and closed to discharge exhaust gas to the exhaust manifold 30.

Furthermore, the combustion chamber 18 includes a first intake port 20.
A plug hole 34 is opened so that the electrode portion of the spark plug 32 is disposed on the inflow direction of intake air from the spark plug 32 .

The first intake port 20 communicates with an intake manifold 36, and an electromagnetic fuel injection device 40 having two injectors 38 in the illustrated embodiment is disposed at an upstream gathering portion of the intake manifold 36.

A primary throttle valve 44 as a mixture throttle valve is disposed downstream of the injector 38 in a portion of a first intake passage 42 that is formed inside the fuel injection device 40 and serves as an intake passage for the mixture. ing.

Further, the upstream side of the fuel injection device 40 is connected to the air cleaner 50 by an intake pipe 48 extending beyond the rocker cover 46 to the side opposite to the side where the fuel injection device is disposed. Therefore, from the first intake passage 42, the fuel injection device 40
A mixture of fuel injected from the air cleaner 50 and air from the air cleaner 50 is supplied.

The intake manifold 36 is formed to be close to or partially in contact with the exhaust manifold 30,
An exhaust manifold 30 is adapted to heat the air-fuel mixture.

An air flow sensor 52 is disposed within the portion of the intake pipe 48 immediately downstream of the air cleaner 50, and in the illustrated embodiment, this air flow sensor 52
The ultrasonic detector 56 detects the Karman vortex number generated on the downstream side of the vortex generation column 54 when the intake airflow passes through the vortex generation column 54 provided in the internal passage, and this detects the Karman vortex number, which is proportional to the air flow rate. It generates a pulse signal that

The pulse signal from the air flow sensor 52 is transmitted to the input side of an electrical control device (not shown), and this control device basically controls the number of fuel injections per unit time and the injection amount, that is, the injector 38, according to the input pulse signal. The fuel injection device 4 determines the injection time and issues an output signal, and actually corrects the basic injection amount according to the operating state of the engine.
0 injectors 38 are driven alternately.

Note that the air flow sensor 52 is provided with a flow rate adjustment bypass 58, which allows a portion of the intake air to bypass the vortex generating column 54, and changes the flow rate over a wide range from the idle state of the engine to the high speed range. The precision and stability of the air flow sensor 52 is maintained by limiting the number of possible Karman vortices within a desired range, and the pulse signal from the air flow sensor 52 is corrected by the bypass flow rate of intake air by the control device. It's summery.

The second intake port 22 communicates with the intake pipe 60,
One end of the intake pipe opens into the inside of a surge tank 62 that communicates with the air cleaner 50, and a second intake passage 64 serving as a secondary air intake passage between the air cleaner 50 and the surge tank 62 has two ends.
Secondary throttle valve 6 as secondary air throttle valve
6 are arranged.

Therefore, only the air from the air cleaner 50 is supplied from the second intake passage 64.

The secondary throttle valve 66 is connected to the primary throttle valve 44 via a cable 68, and is mechanically linked to the accelerator so as to open after the primary throttle valve 44 reaches a predetermined opening degree. Note that only air from another air cleaner other than the air cleaner 50 may be supplied to the second intake passage 64.

The first intake valve 24 is constantly opened and closed by a cam (not shown) on which a camshaft 70 is formed and a rocker arm (not shown) that is swung by the cam. It is set to shorten the valve opening period and to reduce overlap with the valve opening period of the exhaust valve.

Further, the second intake valve 26 is opened and closed by a cam 72 formed on the camshaft 70 and a locking arm 78 equipped with a hydraulic valve operation stop mechanism 76 that swings on the locking shaft 74, or is stopped and moved to the closed position. At the same time, the valve lift is set to be large, the valve opening period is long, and the overlap with the valve opening period of the exhaust valve is large so as to be suitable for high-speed, high-load operation.

Although the structure of the valve operation stop mechanism 76 will not be described in detail, it is configured to engage and disengage a stopper from a plunger that is slidable inside a cylinder attached to a rocker arm 78, and for example, depending on the operating state of the engine. When the control signal (electrical signal) Socv is issued from the control device operated by the hydraulic switching device, hydraulic pressure is supplied from the hydraulic switching device to disengage the stopper from the plunger and stop the operation of the second intake valve 26. When the control signal Socv is cut off, hydraulic pressure is discharged via the hydraulic switching device to engage the stopper with the plunger and open/close the second intake valve 26.

By the way, as mentioned above, the first and second intake valves 2
In the internal combustion engine 10, which is equipped with the second intake valve 26 and which can be activated or deactivated depending on the operating condition of the engine, the 2 intake valve 26
is deactivated, only the first intake valve 24 is activated, and the first and second intake valves are
It is used with both intake valves 24 and 26 in operation.

In addition, especially in a high-load operating state of the internal combustion engine 10 (an operating state near the characteristics indicated by symbols B and C in FIG. 5), when the engine is cold, the second intake valve 2
It is not necessary to delay the ignition timing when the first and second intake valves are not in operation compared to the ignition timing when both the first and second intake valves are in operation. I see, the second intake valve 26
If the ignition timing when the first and second intake valves are not in operation is not delayed relative to the ignition timing when both the first and second intake valves are in operation, knocking or the like will occur.

The relationship between the engine temperature (water temperature in this case) and the retard amount (retard amount) is expressed as shown in FIG. 6 using the load condition as a parameter.

Further, the symbol D in FIG. 5 indicates the fully closed output characteristic.

In this embodiment, the ignition timing when the second intake valve is not operated is appropriately retarded relative to the ignition timing when both the first and second intake valves are operated, depending on the engine temperature state and load state. (Including zero retardation amount.)

That is, as shown in FIGS. 3 and 4, in order to detect the cooling water temperature as the engine temperature of the internal combustion engine 10, a water temperature sensor 115 is provided as a temperature sensor. , 114. As a result, the water temperature sensor 115 outputs an electric signal Sa corresponding to the water temperature, and this water temperature signal Sa
is supplied to the ignition timing calculation circuit 104.

Furthermore, a boost sensor 116 is provided as a load sensor that detects the load state of the internal combustion engine 10, and this boost sensor 116 outputs an electric signal Sb corresponding to the negative pressure of the intake manifold 36, and this boost sensor signal Sb is also supplied to the ignition timing calculation circuit 104.

The ignition timing calculation circuit 104 is composed of an integration circuit 117 and a transistor 118, and this circuit 104 calculates the ignition timing when both the first and second intake valves are operated based on the water temperature signal Sa and the boost sensor signal Sb. Based on the reference, the retard calculation circuit 1 that constitutes the igniter 106 calculates how much the ignition timing should be delayed when the second intake valve is not in operation.
The signal Sc is outputted as a retard amount signal to 05.

On the other hand, a pickup circuit 100 for detecting the timing of the ignition position is provided, and a signal Aa from this pickup circuit 100 (see FIG. 7a) is supplied to a waveform shaping circuit 101 constituting the igniter 106. It's summery.

The igniter 106 receives the ignition position timing signal Aa and the retard amount signal Sc, and supplies a retarded ignition timing signal to the ignition coil 108.

First, the ignition position timing signal Aa is waveform-shaped in the waveform shaping circuit 101, and then this waveform-shaped signal is passed through the circuit ratio control circuit 102 as the signal Ab whose circuit ratio is controlled (see FIG. 7b). The signal is supplied to the retard calculation circuit 105.

The retard calculation circuit 105 receives the retard amount signal Sc.
and the closed circuit rate control signal Ab, the retard amounts θ ₁ , θ ₂
The controlled ignition timing control signal AC or
Ac' (see Fig. 7 c, e) is output, and this signal Ac or Ac' is sent to the amplifier circuit 10.
3.

In the amplifier circuit 103, the ignition timing control signal Ac or Ac' is input, and the control signal Ac or Ac' is input.
The magnitude of Ac' is adjusted appropriately, and the signal whose magnitude has been adjusted is supplied to the ignition coil 108 via the power transistor 107.

In the ignition coil 108, the power transistor 1
Ignition timing signal Ad output from 07 or
Ad' [see Figure 7 d, f], and when the signal (voltage) suddenly falls, the spark plug 3
A large voltage is output to 2.

In addition, from the battery 110 to each circuit 101, 1
Voltage is supplied to the terminals 02 and 103 via a key switch 109.

With the above-described configuration, when the ignition timing calculation circuit 104 receives the signal Sb from the boost sensor 116 and detects a high-load operating state, the signal from the water temperature sensor 115 is
By receiving Sa to the ignition timing calculation circuit,
When it is detected that the water temperature is low (for example, 20°C or less), that is, that the engine is in a cold state, the ignition timing calculation circuit 104 does not issue a signal, so even if the control signal Socv is input, the The ignition timing when the second intake valve is not operating is not delayed relative to the ignition timing when both the first and second intake valves are operating. That is, the advance angle when both intake valves are operated is set to be approximately equal to the advance angle when only the first intake valve is operated.

Next, when it is detected that the water temperature is high (20°C or higher in the above example) during high-load operation,
A signal Sc corresponding to the load condition and water temperature is generated from the ignition timing calculation circuit 104, and the control signal is
When Socv is input, the ignition timing when the second intake valve is not activated is delayed by a predetermined amount with respect to the ignition timing when both the first and second intake valves are activated.

The retard amount control at this time is performed according to the characteristics shown in FIG.

Note that it is also possible to perform the processing in each of the embodiments described above using a microcomputer.

Furthermore, instead of using the water temperature sensor, a sensor that detects other temperatures of the internal combustion engine 10, such as oil temperature, may be used.

In addition, the intake manifold 36 serves as a load sensor.
Instead of the boost sensor 116 that detects the negative pressure of the engine, a sensor that detects the load of various engines, such as a sensor that detects the opening of a throttle valve, may be used.

As described in detail above, according to the ignition timing control device for a multi-cylinder internal combustion engine for a vehicle of the present invention, the ignition timing is controlled when the second intake valve is not operated according to the engine temperature in the high-load operating state of the internal combustion engine. Since it is possible to retard the ignition timing when both the first and second intake valves are activated, it has the advantage of reliably preventing knocking and obtaining sufficient output. Smooth operation can be maintained even when the vehicle is in a state of disrepair.

[Brief explanation of the drawing]

The figures show an ignition timing control device for a multi-cylinder internal combustion engine for vehicles as an embodiment of the present invention. Figure 1 is a plan view of an engine equipped with this device, and Figure 2 is an engine equipped with this device. Figures 3 and 4 are electrical circuit diagrams showing the main parts of the engine, Figure 5 is a graph showing the relationship between the rotational speed and output of the internal combustion engine, and Figure 6 is the water temperature and retard of the internal combustion engine. The graphs illustrating the relationship with the amount, FIGS. 7a to 7f, are all waveform diagrams for explaining the effect. DESCRIPTION OF SYMBOLS 10... Multi-cylinder internal combustion engine, 12... Cylinder head, 14... Cylinder block, 16... Piston, 18... Combustion chamber, 20... First intake port, 22... Second intake port, 24... 1st intake valve, 26...2nd intake valve, 28...exhaust port,
30...Exhaust manifold, 32...Spark plug,
34...Plug hole, 36...Intake manifold, 3
8...Injector, 40...Electromagnetic fuel injection device, 42...First intake passage as an air-fuel mixture intake passage, 44...Primary throttle valve as a mixture throttle valve, 46...Rocker cover, 48... …
Intake pipe, 50... Air cleaner, 52... Air flow sensor, 54... Vortex generating column, 56... Ultrasonic detector, 58... Bypass for flow rate adjustment, 60...
Intake pipe, 62...Surge tank, 64...Second intake passage as an intake passage for secondary air, 66...2
a secondary throttle valve as a secondary air throttle valve;
68...Cable, 70...Cam, shaft, 7
2...Cam, 74...Rotsukashaft, 76...
Hydraulic valve operation stop mechanism, 78...Rotsuka arm,
100...Pickup circuit, 101...Waveform shaping circuit, 102...Closing rate control circuit, 103...
Amplification circuit, 104...Ignition timing calculation circuit, 105
...Retard angle calculation circuit, 106...Igniter, 10
7... Power transistor, 108... Ignition coil, 109... Key switch, 110... Battery, 112... Battery, 113, 114...
...Resistor, 115...Water temperature sensor as a temperature sensor, 116...Boost sensor as a load sensor, 117...Integrator circuit, 118...Transistor.

Claims (1)

[Scope of utility model registration request] A mixture intake passage that is supplied with a mixture of fuel injected from an electromagnetic fuel injection device and air from an air cleaner and has a mixture throttle valve inside, and a secondary air throttle that is supplied only with air from the air cleaner and has an internal mixture throttle valve. A secondary air intake passage having a valve is connected to each cylinder of the internal combustion engine, and the secondary air intake passage is formed to have a larger cross-sectional area than the mixture intake passage. A first intake valve that is normally opened and closed is provided in the intake port where the secondary air intake passage connects to the cylinder, and the intake port where the secondary air intake passage connects with the cylinder is provided with a first intake valve that is normally opened and closed. A multi-cylinder internal combustion engine for a vehicle is provided with a second intake valve that is activated or deactivated by a valve operation/stopping mechanism depending on the operating state of the engine, and a temperature sensor that detects the engine temperature of the internal combustion engine; and a load sensor that detects a load state of the internal combustion engine, and adjusts the ignition timing when the second intake valve is not operated according to the engine temperature in the high-load operating state of the internal combustion engine. A multi-cylinder internal combustion engine for a vehicle, characterized in that an ignition timing control circuit connected to the temperature sensor and the load sensor is provided to retard the ignition timing when both valves are actuated. Ignition timing control device.