JPH044459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for an engine with a controlled number of cylinders, and more particularly to an intake system for an engine with a controlled number of cylinders that controls the number of cylinders to which fuel is supplied depending on the operating state of the engine.

In general, the higher the engine load, the better the fuel efficiency tends to be.In recent years, multi-cylinder engines have stopped the fuel supply to some groups of cylinders when the engine load is light, thereby reducing the fuel consumption of the remaining operating cylinders. Engines that control the number of cylinders are being put into practical use, which relatively increases the load on the engine and improves fuel efficiency in low-load operating ranges. (Refer to JP-A No. 57-338, etc.)
However, in this engine with controlled number of cylinders,
When returning from reduced-cylinder operation to full-cylinder operation, the returning cylinder is in a cooling state, resulting in poor combustibility in that cylinder, and the difference between the generation and torque of this returning cylinder and the torque generated in the cylinder that continues combustion. A problem arises in that an imbalance occurs.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of engines with controlled number of cylinders, the present invention provides an intake system for engines with controlled number of cylinders that can eliminate unbalance in torque generated in each cylinder when returning from reduced-cylinder operation to full-cylinder operation. The purpose is to

The present invention relates to an intake system for a cylinder number control engine that controls the number of cylinders to which fuel is supplied depending on the operating state of the engine. an intake swirl control device that detects when the number of cylinders to which fuel is supplied increases and outputs a detection signal; and a cylinder number increase detection device that detects when the number of cylinders to which fuel is supplied increases and outputs a detection signal; For a predetermined period after the increase, the strength of the swirl of intake air taken into the cylinder to which fuel was being supplied up to that point, that is, the continuous operation cylinder, is increased, and the strength of the swirl of intake air taken into the cylinder to which fuel supply had been stopped up to that point, that is, the cylinder that was in continuous operation, is increased. This is characterized by the provision of a correction device that makes the strength of the intake swirl of the cylinder different.

That is, in the present invention, when returning from reduced-cylinder operation to full-cylinder operation, for example, the
No. 74021, etc., the intake swirl control device is used to weaken the swirl of the intake air in the continuously operated cylinder, suppress the combustibility in that cylinder, and thereby reduce the output torque of the resumed cylinder and the continuously operated cylinder. This is to bring them to the same level.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An intake system for an engine with controlled number of cylinders according to a preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an intake system for a cylinder number controlled engine according to an embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views taken along lines - and - in FIG. 1, respectively.

In the figure, the symbol E indicates a four-cylinder engine installed in a car (not shown), and this engine E
As will be explained in detail later, in low-load operating conditions such as idling or deceleration, only the outer cylinders, that is, the first and fourth cylinders _E1 and _E4 , operate, and the inner cylinders, that is, the second and third cylinders, operate. Cylinder E ₂
The number of cylinders is controlled so that E3 and _E3 are stopped.

The intake system of the engine E includes an intake pipe section 1, a carburetor 2 including a throttle valve 2a (see FIGS. 2 and 3), and an intake manifold 3.
This intake manifold 3 is connected to the first to fourth cylinders.
It includes first to fourth cylinder manifold portions 3a, 3b, 3c, and 3d which are respectively connected to _E1 to _E4 separately.

The second and third cylinders E ₂ and
The intake manifold parts 3b and 3c of _E3 are equipped with shutter valves 4a and 4b for controlling the number of cylinders.
are arranged. These shutter valves 4a, 4b
are fixed to a common valve shaft 5, which valve shaft 5 is rotatable about its longitudinal axis. When the valve shaft 5 rotates, the shutter valves 4a and 4b simultaneously rotate to open and close the second and third intake manifold sections 3b and 3c. An actuator 7, which is an electromagnetic solenoid, is operatively connected to the valve shaft 5 via a transmission mechanism 6.

This actuator 7 is connected to a cylinder number control circuit 8, receives an excitation signal _D1 from this circuit 8,
The valve shaft 5 is rotated in response to this excitation signal _D1 to close the shutter valves 4a and 4b, which are normally open. The cylinder number control circuit 8 has an engine rotation speed sensor 9 at its input end that detects the rotation speed of the engine E and outputs a rotation speed signal _S1 indicating the rotation speed, and a suction pipe negative pressure for detecting the engine load. output of a negative pressure sensor 10 that detects the negative pressure and outputs a negative pressure signal S ₂ according to the negative pressure, and a water temperature sensor 11 that detects the cooling water temperature and outputs a water temperature signal S ₃ according to the cooling water temperature. The ends are connected, the water temperature signal _S3 is above a predetermined value, and the coordinates indicated by the rotational speed signal _S1 and negative pressure signal _S2 are indicated by hatching in the cylinder number control map in FIG. When the cylinder is in the partial cylinder operation region A, the excitation signal _D1 is output. As mentioned above, when the shutter valves 4a and 4b are closed, no air is taken into the second and third cylinders E2 _{and E3} , and therefore the cylinders _E2 and E3 are in a rest state, and the first and third cylinders E2 and _E3 are in a rest state. A partial cylinder operation state occurs in which only the four cylinders E ₁ and E ₄ operate.

In FIGS. 2 and 3, the reference numeral 12 indicates a cylinder block, and a piston 13 is slidably fitted into the cylinder block 12, and the piston 13 can reciprocate up and down. The size of the combustion chamber 14 formed above the combustion chamber 14 is increased or decreased. At the top of this combustion chamber 14,
An intake port 15 and an exhaust port 16 are formed, and the intake port 15 is connected to the intake manifold 3.
However, an exhaust manifold 17 is connected to each exhaust port 16. The intake port 15 and the exhaust port 16 each have an intake valve 18.
and exhaust valves 19 are provided, and these intake and exhaust valves 18 and 19 are opened and closed at predetermined timings by a valve operating mechanism 20, respectively, in synchronization with the rotation of the engine.

Combustion chamber 14 formed in the silling block 12 of the intake manifold sections 3a, 3b, 3c, 3d
The inside of the adjacent part is a primary side intake passage 22a whose passage area is set relatively small by the partition wall 21.
and a secondary intake passage 22b having a relatively large passage area. The secondary intake passages 22b of the intake manifold portions 3a, 3b, 3c, and 3d are provided with sub-throttle valves 23a, 23b, 23c, and 23d that open and close the passages 22b, respectively.
is installed. Sub-throttle valves 23a and 23
d is the sub-throttle valve 2 on the valve shaft 24a.
3b and 23c are fixed to the valve shaft 24b, respectively, and these valve shafts 24
a, 24b are adapted to rotate about their longitudinal axes. Sub-throttle valve 23
a, 23d rotate simultaneously when the valve shaft 24a rotates, and the intake manifold portions 3a,
The secondary side intake passage 22b of 3d is opened and closed. On the other hand, the sub-throttle valves 23b, 23c
rotates at the same time as the valve shaft 24b rotates to open and close the secondary intake passages 22a of the intake manifold portions 3b and 3c. Actuators 26a and 26b, which are electromagnetic solenoids, are operatively connected to the valve shafts 24a and 24b via transmission mechanisms 25a and 25b, respectively.

The actuators 26a, 26b are connected to an auxiliary throttle valve control circuit 27, receive excitation signals _D2 , _D3 from this circuit 27, and actuate the valve shafts 24a, _D3 in response to the excitation signals _D2 , D3, respectively.
24b to open the sub-throttle valves 23a, 2.
The opening/closing of 3b, 23c, and 23d is controlled. The auxiliary throttle valve control circuit 27 has its input end connected to the negative pressure sensor 10 and the output end of the cylinder number control circuit 8. The auxiliary throttle valve control circuit 27 is configured to receive a switching signal _S4 from the cylinder number control circuit 8 indicating switching from reduced cylinder operation to full cylinder operation. During normal operation when the switching signal _S4 is not received, the sub-throttle valve control circuit 27 outputs excitation signals _D2 and _D3 of the same value in response to the load signal _S2 , and controls the sub-throttle valves 23a, 23b, 23c and 23d are placed in the same open state or the same closed state. Further, during the switching operation when receiving the switching signal _S4 , the sub-throttle valve control circuit 27 outputs the excitation signal D3 according to the load signal _S2 , and outputs the excitation signal _D3 calculated according to the load signal _S2 . Set voltage signal △D to excitation signal D ₃
is added to output the excitation signal D' ₂ to adjust the opening degrees of the sub-throttle valves 23a and 23d.
The opening degree should be larger than that of b and 23c. This reduces the swirl of the intake air in the continuously operated cylinders E ₁ and E ₄ , suppressing the combustibility in these cylinders E ₁ and E ₂ ,
By setting the combustibility to almost the same level as the return cylinders E ₂ and E ₃ , all cylinders E ₁ , E ₂ , E ₃ ,
It is designed to balance the generated torque in E ₄ .

Next, referring to FIG. 5, the cylinder number control circuit 8
A more or less specific electrical circuit of the sub-throttle valve control circuit 27 will now be described.

The cylinder number control circuit 8 has first, second, and third comparators 31, 32, and 33. One input terminal of the first, second, and third comparators 31, 32, and 33 has an engine speed sensor 9 and a negative pressure sensor 10, respectively.
and the output end of the water temperature sensor 11 are connected, and the output ends of the first, second, and third set value signal generation circuits 34, 35, and 36 are connected to the other input end, respectively. First set value signal generation circuit 34
outputs a first set value signal e1 indicating the value of the engine speed to be switched to partial cylinder operation. The second set value signal generation circuit 35 outputs a second set value signal e2 indicating the value of the intake pipe negative pressure to be switched to partial cylinder operation. The third set value signal generation circuit 36 outputs a third set value signal e3 indicating a temperature indicating the boundary between the engine cold state and warm engine state.

The first comparator 31 includes an engine rotation speed signal S
1 is smaller than the first set value signal e1, a Hi signal is output, and when it is larger, a Low signal is output. The second comparator 32 outputs a negative pressure signal S2
When is smaller than the second set value signal e2, a Hi signal is output, and when it is larger, a Low signal is output. The third comparator 33 outputs a Hi signal when the water temperature signal S3 is larger than the third set value signal e3, and outputs a Low signal when it is smaller. That is, when the engine is in a cold state, the third comparator 33 generates a Low signal to prevent the number of cylinders from being controlled, thereby improving the combustibility of the engine.

The first, second and third comparators 31, 32, 33
The output ends of are connected to the input ends of the AND circuit 37, respectively. This AND circuit 37 operates when the output signal signal of the third comparator 33 is in a Hi state, that is, the engine is in a warm-up state, and the output signals of the first and second comparators 31 and 32 are both Hi.
When in this state, it outputs a Hi signal. That is, the AND circuit 37 operates when both the engine speed and the intake pipe negative pressure are below the set values.
That is, when the relationship between the engine speed and the intake pipe negative pressure is in the partial cylinder operation region indicated by A in FIG. 4, the Hi signal is output.
The output terminal of this AND circuit 37 is connected to a drive circuit 3 that outputs an excitation signal D1 for the actuator 7.
8 is connected at its input. When the drive circuit 38 receives the Hi signal from the AND circuit 37, it generates the excitation signal D1 to excite the actuator 7, and as a result, the shutter valves 4a,
4b is closed, air intake to cylinders E2 and E3 is stopped, and partial cylinder operation is performed by cylinders E1 and E4.

Next, the configuration of the sub-throttle valve control circuit 27 will be explained in detail.

The sub-throttle valve control circuit 27 has a sub-throttle valve opening/closing control data generator 40 that generates sub-throttle valve opening/closing control data Ds for controlling the opening/closing of the sub-throttle valves 23a to 23d. This sub-throttle valve opening/closing control data is based on the relationship between the sub-throttle valve opening and negative pressure that can minimize the fuel consumption rate, as explained in detail in the patent application pending by the present applicant. This shows that.
The above data is based on the experimental results of the inventors of this application, and the sub-throttle valve should be kept fully open (0°) during extremely low load operation of the engine, including idling operation with an intake negative pressure of -520 mmHg or more. The fuel consumption rate can be minimized by the most frequently used intake negative pressure -520 to -150
During low and medium load operation of the engine in the mmHg range,
This shows that the fuel consumption rate in this operating range can be minimized by keeping the auxiliary throttle valve at a relatively low opening of, for example, about 20 degrees.

The output end of the negative pressure sensor 10 is connected to the input end of the data generator 40, and the data generator 40 receives a negative pressure signal S from the negative pressure sensor 10.
2, the negative pressure signal S2 is compared with the data Ds, the auxiliary throttle valve opening corresponding to the negative pressure signal S2 is read out, and an opening signal indicating the auxiliary throttle valve opening is output. A drive circuit 41 is connected to the output end of the data generator 40, and this drive circuit 41 receives the opening degree signal and receives the signal SS.
The excitation signals D2 and D3 corresponding to 4 are output to the actuators 26a and 26b. Note that in the normal state, D2 and D3 have the same value, so they may be output from the same output terminal.

Sub-throttle valve control circuit 2 configured as described above
According to No. 7, in the normal state, the sub-throttle valve 2
3a to 23d are appropriately controlled to open the combustion chamber 14.
It is possible to maintain an appropriate swirl within the fuel and maintain good combustibility.

However, when switching from reduced-cylinder operation to full-cylinder operation using the cylinder number control circuit 8, since the returning cylinder is cooled as described above, the generated torque between the returning cylinder and the continuously operating cylinder is There is a problem in that it creates an imbalance.

Therefore, in the present invention, when switching from reduced-cylinder operation to full-cylinder operation, the intake swirl of cylinders E1 and E4, which are continuously operated cylinders, is weakened to
1. The torque generated by E4 is transferred to cylinder E, which is the return cylinder.
2. In order to balance the generated torque of E3,
A sub-throttle valve opening correction circuit 42 is provided. This correction circuit 42 includes a switching detection circuit 43 connected to the output terminal of the AND circuit 37.
This switching detection circuit 43 detects when the output signal of the AND circuit 37 switches from the Hi state to the Low state.
That is, when switching from reduced cylinder operation to full cylinder operation, this is detected and a switching signal S4 is output.

The output terminal of this switching detection circuit 43 is connected to a timer 44.
This timer 44 is connected to the input terminal of
When receiving the switching signal S4 from the switching detection circuit 43, it outputs a timer signal T indicating a predetermined correction period. The output terminal of this timer 44 is connected to the input terminal of a set voltage generator 45, and this set voltage generator 45 outputs a set voltage signal ΔD while receiving the timer signal T. It's getting old.

An adder 46 is interposed between the drive circuit 41 and the actuator 26a, and one input terminal of the adder 46 is connected to the output terminal of the drive circuit 41, and its output The end is connected to actuator 26a. This adder 46 has the other input terminal connected to the output terminal of the set voltage generator 45, and converts the set voltage signal ΔD from the set voltage generator 45 into the excitation signal D2 from the drive circuit 41. In addition, a signal D2' is output. The state of this signal D2' is shown in FIG. 6 by a dashed line.

In the above configuration, at times other than when switching from reduced-cylinder operation to full-cylinder operation, the actuators 26a and 26b receive excitation signals D2 and D3 of the same value from the drive circuit 41, and operate the sub-throttle valve 2.
4a, 24d, 24b, and 24c are opened and closed at the same opening degree, and the swirl of intake air in the cylinders E1, E4, E2, and E3 is adjusted to the same intensity. On the other hand, when switching from reduced cylinder operation to full cylinder operation, actuator 26b operates in the same way, but actuator 2
6a, the setting voltage generator 45 generates the setting voltage signal ΔD.
, the adder 46 outputs the signal D2' (=d
2+ΔD), and in response to this signal D2', the sub-throttle valves 23a and 23d are operated in the direction of opening further. As a result, the intake swirl of cylinders E1 and E4, which are continuous cylinders, is made weaker than the intake swirl of cylinders E2 and E3, which are return cylinders, and as a result, the generated torques of cylinders E1, E2, E3, and E4 are balanced. It becomes like this.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an intake system for a cylinder number controlled engine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, and FIG. 4 is a diagram showing the cylinder number control map for switching between reduced cylinder operation and full cylinder operation, and FIG. 5 is a circuit showing the electric circuit of the cylinder number control circuit and the sub-throttle valve control circuit. 6 are graphs showing sub-throttle valve opening/closing control data. E...Engine, E1, E2, E3, E4...
Cylinder, 4a, 4b... Shutter valve, 7... Actuator, 8... Cylinder number control circuit, 23a,
23b, 23c, 23d... Sub-throttle valve, 2
6a, 26b... actuator, 27... auxiliary throttle valve control circuit.

Claims (1)

[Scope of Claims] 1. In an intake system for a cylinder number control engine that controls the number of cylinders to which fuel is supplied according to the operating state of the engine, the swirl of intake air taken into the cylinder to which fuel is supplied is controlled according to the operating state. an intake swirl control device that performs variable control, a cylinder number increase detection device that detects when the number of cylinders to which fuel is supplied increases and outputs a detection signal, and a detection device that receives the cylinder number increase detection device; For a predetermined period after the number of cylinders increases, the strength of the swirl of the intake air drawn into the cylinders to which fuel had been supplied up to that point is compared to that of the intake air drawn into the cylinders to which fuel supply had been stopped up to that point. An intake system for an engine that controls the number of cylinders, characterized by being provided with a correction device that makes the strength of swirl different. 2. The correction device receives a detection signal from the cylinder number increase detection device, and for a predetermined period from the time when the number of cylinders increases, reduces the swirl of intake air taken into the cylinder to which fuel has been supplied up to that point. 2. The intake system for an engine with a controlled number of cylinders according to claim 1, wherein the strength of the swirl of the intake air of the cylinder to which fuel supply has been stopped up to that point is made weaker than the strength of the swirl of the intake air of the cylinder to which fuel supply has been stopped up to that point.