JPH0243895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a knocking control device mainly applied to an automobile engine.

[Prior Art] Many modern automobile engines are equipped with a supercharger such as an exhaust turbocharger or have a higher compression ratio in order to achieve higher efficiency. It is more likely to occur. Knocking is air column vibration that occurs due to self-ignition of end gas in the combustion chamber, and it not only produces unpleasant sounds and vibrations, but may also be accompanied by a reduction in output. If excessive knocking occurs frequently, there is a risk that the spark plug, valve, or piston may be damaged by melting, resulting in a disadvantage that the durability of the engine is significantly reduced. Therefore, this type of engine is generally equipped with a knocking control device to suppress the occurrence of harmful knocking.

As a prior art related to this type of knocking control device, there is one disclosed in Japanese Patent Application Laid-Open No. 138435/1983. That is, in this engine, a knock sensor for detecting knocking is provided in the engine body, and when the knocking sensor detects the occurrence of knocking, the air-fuel ratio is corrected to the rich side. Note that conventional air-fuel ratio control is performed by changing the opening degree of the air bleed passage or the main jet.

[Problems to be Solved by the Invention] However, when the air-fuel ratio is corrected by changing the opening degree of the air bleed passage or the main jet as described above, a special actuator is required to adjust the opening degree. It becomes necessary. Therefore, there are problems in that the number of parts increases, the structure becomes complicated, and costs increase. Further, in such air-fuel ratio control, there is a problem that a time delay tends to occur in increasing the amount of fuel, and it is difficult to perform accurate control with high responsiveness. A knocking control method that does not cause such inconvenience is to immediately open the waste gate valve installed in the turbine section of the exhaust turbocharger when the occurrence of knocking is detected, thereby reducing the boost pressure. It is conceivable to suppress this knocking. However, if the wastegate valve is opened every time knocking occurs, it becomes difficult to improve the engine output, and the existence value of the exhaust turbocharger is greatly diminished.

[Means for solving the problem] In order to solve the problem, the present invention directly changes the air-fuel ratio by using an electromagnetic fuel injection pump provided as an alternative element to the mechanical acceleration pump. In addition, only when knocking cannot be suppressed completely by the air-fuel ratio control, the occurrence of knocking is suppressed by exceptionally controlling the opening of the waste gate valve. That is, in the present invention, when the knock sensor detects the occurrence of knocking, the control means outputs a signal to the fuel injection pump indicating that fuel should be discharged according to the degree of knocking, and accordingly The present invention is characterized in that it is configured to output a signal indicating that the waste gate valve should be opened when the occurrence of knocking cannot be suppressed.

[Effect] Therefore, when knotting occurs,
Fuel corresponding to the amount is discharged from the fuel injection pump to the intake system passage, and the air-fuel ratio is instantaneously corrected to the rich side, thereby quickly suppressing knocking. In addition, if there is severe knocking that cannot be suppressed by controlling the air-fuel ratio alone, the wastegate valve will be opened next, reducing the boost pressure and reliably suppressing the knocking. .

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a system explanatory diagram schematically showing an automobile gasoline engine, in which 1 is the engine body, 2 is an intake system path, and 3 is an exhaust system path. The intake system passage 2 has a starting end open to the atmosphere via an air cleaner (not shown) and a terminal end communicating with the combustion chamber 5 of the engine body 1 via an intake valve 4, with a carburetor 6 intervening in the middle. It has been set up. The carburetor 6 has a first system 6a and a secondary system 6b.The throttle valve 7 of the first system 6a opens and closes depending on the amount of depression of the accelerator pedal, while the throttle valve 8 of the secondary system 6b It is connected to a diaphragm mechanism 9 that is activated by the pressure within the intake system passage 2, and is designed to open mainly in a high load range. The exhaust system path 3 has a starting end communicating with the combustion chamber 5 via an exhaust valve 11 and a terminal end opening to the atmosphere through a muffler (not shown), etc., and this exhaust system path 3 and the intake air Exhaust turbocharger 1 is connected between system line 2
2 are provided. The exhaust turbocharger 12 is
a compressor section 13 interposed in a portion of the intake system path 2 upstream of the carburetor 6; and the exhaust system path 3.
a turbine section 14 that is interposed in the middle and rotates by exhaust energy to drive the compressor section 13;
A waste gate valve 15 is provided in parallel to the turbine section 14. The wastegate valve 15 is for bypassing exhaust gas to decelerate the turbine section 14, and energizes a wastegate controller 16 that operates in response to an electrical signal input from a boost pressure sensor (not shown) or the like. It has been designed to open and close.

Note that the carburetor 6 does not have a mechanical acceleration pump, but is equipped with an electromagnetic fuel injection pump 17 as an alternative element. Fuel injection pump 17
As shown in FIG. 2, a piston 21 is housed in a cylinder 19 that forms a pump chamber 18, and the piston 21 is moved forward and backward by the urging force of a spring 22 and the electromagnetic attraction force of a solenoid 23 to operate the pump. It is configured so that it can perform its functions. The pump 17 also includes an inlet 24 and an outlet 25 that communicate with the pump chamber 18, respectively.
The inlet 24 is connected to the float chamber 28 of the carburetor 6 through an inlet passage 27 having a check valve 26, and the outlet 25 is connected to the intake air of the carburetor 6 through an outlet passage 31 having a check valve 29. It opens into the passage 32. This fuel injection pump 17 is controlled by a microcomputer 33. The microcomputer 33 includes a central processing unit 34, a memory 35,
A detection signal from an opening detector 38 for detecting the open position of the throttle valve 7 is input to the interface 36. . The memory 35 of this microcomputer 33 contains the following program. That is, the detection signal a from the opening detector 38 is sequentially read and the read position information of the throttle valve 7 is second-order differentiated with respect to time to calculate the acceleration of the throttle valve 7 in the opening direction.
Then, by comparing the calculated value with a set value, if it is determined that the throttle valve 7 is opened at an acceleration of a certain level or more, a command indicating that acceleration fuel should be discharged toward the fuel injection pump 17 is determined. signal b
Output. Specifically, the fuel injection pump 1
A pulse voltage is applied to the solenoid 7 a predetermined number of times.

An engine having such a configuration is provided with a knocking control device according to the present invention. This knocking control device includes a knock sensor 4 for detecting knocking.
1. When the knock sensor 41 detects the occurrence of knocking, it first outputs a signal to the fuel injection pump indicating that fuel should be discharged, and when the knocking cannot be controlled completely by this. and control means for outputting a signal to the wastegate valve controller indicating that the wastegate valve should be opened. In this embodiment, the microcomputer 33 plays the role of the control means. In detail, the knock sensor 41
For example, the vibration of the cylinder block 42 excited by the air column vibration of knocking is converted into an electric signal d by a piezoelectric element, and the electric signal d is sent to the interface 36 of the microcomputer 33. I am trying to input it. In addition to the above-mentioned programs, the microcomputer 33 includes the following programs and data. That is, the relationship between the degree of knocking and the optimal fuel increase value for suppressing the knocking is determined through experiments and the like, and the data is stored in the memory 35. Then, when the occurrence of knocking is confirmed by the signal d input from the knock sensor 41 and the intensity of the knocking is detected, a fuel increase value corresponding to the knocking intensity is selectively retrieved from the memory 35; A number of pulse signals c corresponding to the fuel increase value are output from the interface 37 to the fuel injection pump 17. Further, the relationship between the knocking intensity and the opening degree (minimum value) of the waste gate valve necessary to suppress the knocking is stored in the memory. If the knocking detection signal d from the knock sensor 41 continues to be input even if the fuel increase value commanded to the fuel injection pump 17 reaches a preset maximum value,
The wastegate valve opening degree corresponding to the strength of the knocking is selectively retrieved from the memory 35, and an opening command signal e corresponding to the opening degree is outputted to the wastegate controller 16. The wastegate controller 16 is configured to duty-control the wastegate valve 15, to ensure a substantial opening corresponding to the opening command signal e, and to bypass a required amount of exhaust gas.

With such a configuration, when the throttle valve 7 is opened at a constant acceleration, a number of pulse voltages corresponding to the degree of acceleration are applied to the solenoid 23 of the fuel injection pump 17, and the pulse voltage is applied to the solenoid 23 of the fuel injection pump 17. The piston 21 reciprocates a number of times corresponding to the number, and the necessary fuel is discharged into the intake passage 32 of the carburetor 6. As a result, the main jet (not shown)
This compensates for the fuel lag from the start and provides appropriate acceleration. Further, when knocking occurs, a signal d to that effect is provided from the knock sensor 41 to the microcomputer 33. As a result, the microcomputer 33 outputs a signal c indicating that fuel should be discharged according to the degree of knocking, and the fuel injection pump 17 operates a number of times corresponding to the signal c to pump fuel into the intake passage 3. Discharge to. Therefore, the air-fuel ratio is instantaneously corrected to the rich side, and knocking is quickly suppressed.
Note that if the occurrence of knocking cannot be suppressed only by such air-fuel ratio control, an opening command signal e is outputted from the microcomputer 33 to the wastegate controller 16. As a result, the waste gate valve 15 opens to the actual opening degree corresponding to the signal e.
A portion of the exhaust gas is bypassed and the turbine section 14 is decelerated. Therefore, the boost pressure is reduced and the occurrence of knocking is quickly suppressed.

In this way, knocking can be suppressed, but in this case, the electromagnetic fuel injection pump 33, which is provided as an alternative element to the acceleration pump, is used to correct the air-fuel ratio when knocking occurs. Therefore, control with higher responsiveness is possible than in the case where the air-fuel ratio is corrected by air bleed or main jet opening adjustment, and knocking can be suppressed quickly and accurately. Also,
When the function of the fuel injection pump 17 for acceleration is utilized in this way, there is no need for any special actuator, valve, etc. for knocking control.
In particular, in this embodiment, the knock sensor 41
This can be implemented simply by adding the following and expanding the program in the microcomputer 33. Therefore, it has the advantage that the number of parts is small, the structure is simple, and it can be easily implemented. Moreover, if a situation occurs where knocking cannot be suppressed by air-fuel ratio control alone, the waste gate valve 15 is opened to lower the boost pressure, so even if severe knocking occurs, the The situation can be brought under control quickly.
Since the opening degree control of the waste gate valve 15 is performed only when a specific situation occurs as described above, when knocking is suppressed only by controlling the opening and closing of the waste gate valve 15. This eliminates the disadvantage of causing a decrease in output as in the case of the above, and allows the exhaust turbocharger 12 to effectively exert its power-up function.

In the above embodiment, a case has been described in which the microcomputer for accelerating fuel increase control also plays a role as a control means for knocking control, but the present invention is not necessarily limited to such a device. For example, a control means for increasing the amount of acceleration fuel and a control means for knocking control may be provided separately.

In addition, the method of determining the fuel discharge amount and the opening degree of the waste gate valve depending on the degree of knotting is as follows.
The method is not limited to the map method described above. for example,
A formula showing the relationship between the degree of knotting and the amount of fuel discharged and the opening degree of the wastegate valve is stored in memory, and the formula is used to calculate the optimal amount of fuel discharged and the opening degree of the wastegate valve each time. Good too.

[Effects of the Invention] Since the present invention has the above configuration, it has a small number of parts, a simple structure, and is easy to implement.Moreover, it has high responsiveness and can quickly and accurately suppress knocking. Furthermore, it is possible to provide a knocking control device that can sufficiently secure the power-up effect of the exhaust turbocharger and prevent a decrease in output.

[Brief explanation of drawings]

FIG. 1 is a system explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a schematic sectional view of a fuel injection pump in the same embodiment. 1...Engine body, 2...Intake system path, 3...
Exhaust passage, 5... combustion chamber, 6... carburetor, 12...
...Exhaust turbo charger, 15...Wastegate valve, 16...Wastegate controller, 17...Fuel injection pump, 33...Control means (microcomputer).

Claims (1)

[Claims] 1. A carburetor that eliminates the mechanical acceleration pump, an electromagnetic fuel injection pump provided as a replacement element for the acceleration pump, and a compressor section disposed upstream of the carburetor and a turbine that drives the compressor section. This is a knocking control device for an edge, which includes an exhaust turbocharger having a wastegate valve arranged in parallel in the exhaust turbocharger, and a wastegate controller that opens and closes the wastegate valve. When the occurrence of knocking is detected, a signal is first output to the fuel injection pump indicating that fuel should be discharged, and if the occurrence of knocking cannot be suppressed, the waste is sent to the waste gate controller. A knocking control device comprising: control means for outputting a signal indicating that a gate valve should be opened.