JPH04143439A - Intake air pressure detector of engine - Google Patents

Abstract

PURPOSE:To enable characteristics of detected pressure to accurately match an intake air quantity by providing means for detecting the intake air pressure in a communication passage which provides communication between primary and secondary intake air passages independent from each other. CONSTITUTION:There are provided primary and secondary control valves 22, 32 which adjusts under mutual interlocking ain intake air quantity supplied to an engine 10 respectively, in mutually independent primary and secondary air intake passages 20, 30 which supply intake air to the engine 10. A changeover valve 33 which makes opening operation in a specified high intake air range is provided downstream from a secondary control valve 32. A communication passage 40 which provides communication between a position located downstream from the primary control valve 22 and a position located between the secondary control valve 32 and the changeover valve 33 is provided in the communication passage 40. Consequently, since the characteristic of the pressure detected by the pressure sensor 51 is independent of changeover between both intake passages 20, 30 or the like, the characteristic can accurately match the intake air quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an intake pressure detection device for an engine, and more particularly, to one in which an intake passage is composed of a primary intake passage and a secondary intake passage that are independent from each other.

(Prior Art) Conventionally, there is no known system that performs the so-called D-JETRO type fuel injection control, which detects the intake pressure of the engine corresponding to the intake air amount and calculates the fuel injection amount based on it. It is being As one technique, for example, as disclosed in Japanese Patent Application Laid-open No. 156946/1983,
A pressure sensor is installed in the intake passage of the engine, and the pressure sensor detects the intake pressure.The output signal of the pressure sensor is passed through a low-pass filter, and then smoothed and predetermined calculation processing is performed to determine the fuel injection amount. There is a method that calculates .

(Problem to be Solved by the Invention) By the way, the intake passage that supplies intake air to the engine is configured with a primary intake passage and a secondary intake passage that are independent of each other, so that the intake passage can be used to reduce the intake air during low loads when less output is required. In the high intake air volume range, intake air is supplied only through the fry-mary intake passage, and in a high intake air volume area, such as when a large output is required under high load, intake air is supplied through both intake passages. When applying fuel injection control based on intake pressure as described above to such an engine, a pressure sensor is installed in the primary intake passage where intake air is constantly supplied, and the pressure sensor detects the intake pressure. It is common practice to calculate the fuel injection amount based on the pressure signal.

However, in this case, the characteristics of the detected intake pressure with respect to the intake air amount differ between when intake air is supplied only through the primary intake passage and when intake air is supplied through both the primary intake passage and the secondary intake passage. Because it changes,
Control corresponding to this is required. In other words, even if the amount of intake air to the engine is the same when using only the primary intake passage and when using the primary intake passage and secondary intake passage, the air flow rate and air flow velocity flowing through the primary intake passage will change. , the pressure inside the primary intake passage changes, and therefore, as shown in FIG. 4, the intake pressure characteristics change depending on whether only the primary intake passage is used or when the primary and secondary intake passages are used. Here, in FIG. 4, the solid line shows the characteristic of intake pressure with respect to intake air amount when only the primary intake passage is used, and the broken line shows the characteristic of intake pressure with respect to intake air quantity when only the primary and secondary intake passages are used. For example, when intake air is being supplied only through the primary intake passage and the intake pressure is PMl, when switching is made so that intake air is supplied through both the primary and secondary intake passages, the air flow rate and air in the primary intake passage will change. The flow rate decreases and the intake pressure changes to PM2.

However, the amount of intake air decreases between the roads before and after switching the intake passages.
Therefore, the intake pressure must be controlled by switching from the characteristic shown by the solid line to the characteristic shown by the broken line. As described above, when switching the intake passage, complicated corrections such as changing the intake pressure characteristic to another different characteristic and controlling the intake pressure must be performed.

As a countermeasure to this problem, it is possible to detect the intake pressure from both the primary intake passage and the secondary intake passage and control using the combined intake pressure, but in this case,
A problem arises in that piping and the like become complicated in order to take out the pressure.

Furthermore, during the above-mentioned transition of intake passage switching, the air flow velocity in the primary intake passage changes rapidly, and the dynamic pressure due to the air in the primary intake passage also changes significantly, causing the intake air detected by the pressure sensor to change rapidly. The pressure also fluctuates greatly, and there is also the problem of erroneously detecting the intake pressure.

The present invention has been made in view of the above points, and an object of the present invention is to detect the intake pressure of an engine equipped with a primary intake passage and a secondary intake passage that are independent of each other. The purpose of this invention is to ensure that the pressure characteristics always accurately correspond to the amount of intake air, without being affected by switching between the two intake passages.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a communication passage that communicates the primary intake passage and the secondary intake passage,
Therefore, the intake pressure is detected.

Specifically, the solution taken by the present invention is that a primary intake passage and a secondary intake passage are provided independently from each other for supplying intake air to the engine, and that the primary intake passage and the secondary intake passage are respectively provided and interlocked with each other to supply intake air to the engine. A primary control valve and a secondary control valve that adjust the amount of intake air to be supplied; a switching valve that is provided downstream of the secondary control valve in the secondary intake passage and opens in a predetermined high intake air amount region; and the primary intake passage. an intake pressure detection means for detecting the pressure of intake air in the communication passage, the communication passage communicating between a downstream part of the primary control valve and a part of the secondary intake passage between the secondary control valve and the switching valve; The configuration is such that the

(Function) With the above configuration, in the present invention, air is supplied to the engine only from the primary intake passage in the low intake air amount region when the switching valve is closed, but the secondary control valve of the secondary intake passage is controlled by the primary control valve. It is linked to a valve,
Moreover, since the primary intake passage and the secondary intake passage are connected to each other by a communication passage on the downstream side thereof, the air flowing through the air cleaner etc. also flows into the secondary intake passage, and after passing through the secondary control valve, the air flows through the communication passage. and flows into the primary intake passage. Therefore, in the communication passage, the combined intake pressure of the primary intake passage and the secondary intake passage is shown.

In addition, in a predetermined high intake air amount region where the switching valve is open, air is supplied to the engine through the primary intake passage and the secondary intake passage, but the communication passage communicates the primary intake passage and the secondary intake passage. Therefore, in the communication passage, the combined intake pressure of the primary intake passage and the secondary intake passage is shown. As a result, the communication passage always shows the combined intake pressure of the primary intake passage and the secondary intake passage regardless of whether the switching valve is opened or closed. Therefore, the characteristics of the pressure detected by the intake pressure detection means provided in this communication passage with respect to the intake air amount do not change even when the switching valve is opened or closed, that is, the intake passage is switched. In other words, the characteristic of the intake pressure with respect to the intake air amount to the engine is expressed as one characteristic regardless of the switching of the intake passage.

Furthermore, when the switching valve operates from closed to open, that is, when the intake air is switched from being supplied only through the primary intake passage to being supplied through the primary and secondary intake passages, in the communication passage, both intake passages are The communication effect reduces the influence of fluctuations in intake pressure due to changes in air flow, prevents erroneous detection of intake pressure, and consistently detects intake pressure that corresponds to the amount of intake air with high accuracy.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a rotary piston engine equipped with an intake pressure detection device according to an embodiment of the present invention.

In the figure, 10 is a rotary piston engine, and 11 is its casing. This casing 11
One side housing of the primary intake boat 2
1, and secondary intake boats 31 are independently opened in the other side housing. A primary intake passage 20 and a secondary intake passage 30, which are independent from each other, are connected to the primary intake boat 21 and the secondary intake boat 31, respectively.

In the primary intake passage 20, a primary control valve 22 that adjusts the amount of air flowing through the primary intake passage 20, and a primary injector 23 that injects fuel into the primary intake passage 20 are arranged in order from the upstream side. . Further, in the secondary intake passage 30, in order from the upstream side, there is a secondary control valve 32 that adjusts the amount of air flowing through the secondary intake passage 30, and a secondary control valve 32 that is driven to open and close by an actuator 35 so as to open in a predetermined high intake amount region, which will be described later. A switching valve 33 and a secondary injector 34 that inject and supply fuel to the secondary intake passage 30 are provided.

A portion of the primary intake passage 20 on the downstream side of the primary control valve 22 and a portion of the secondary intake passage 30 between the secondary control valve 32 and the switching valve 33 are communicated by a communication passage 40. A pressure extraction port 41 is opened in the communication passage 40, and the pressure extraction port 41 communicates with a pressure sensor 51 as an intake pressure detection means via a filter 42. This pressure sensor 5
1 detects the intake pressure in the communication passage 40, and its output signal is input to the control unit 50.

The primary control valve 22 and the secondary control valve 32 are interlocked with each other and open in response to the amount of depression of an accelerator pedal (not shown).

As shown in FIG. 2, the switching valve 33 operates in the range shown by the shaded area, that is, when the opening degree of the primary control valve 22 is 1/2 or more, or when the engine speed is 300 Orpm or more, the intake air amount is high. The actuator 35 is driven to open and close by an actuator 35 so as to open in the region and close in other low intake air amount regions, and the operation of the actuator 35 is controlled by a control unit 50.

Further, the operation of the primary injector 23 and the secondary injector 34 is controlled by a control unit 50.

The control unit 50 receives output signals from various sensors such as a rotational speed sensor 52 that detects the engine rotational speed and a throttle position sensor 53 that detects the opening degree of the primary control valve 22.

With the above configuration, the air supplied to the engine 10 is
In the low intake air amount region where the switching valve 33 is closed, the air flows into both the primary intake passage 20 and the secondary intake passage 30 via an air cleaner (not shown), and the air that flows into the secondary intake passage 30 flows through the secondary control valve 32. After passing through, it flows into the primary intake passage 20 through the communication passage 40. Then, air is supplied to the engine 10 only from the primed intake passage 20, and by increasing the intake flow velocity, vaporization and atomization of the fuel can be promoted, and combustibility can be improved.

On the other hand, in a predetermined high intake air amount region where the switching valve 33 is open, the air supplied to the engine is supplied from both the primary intake passage 20 and the secondary intake passage 30, so that a large amount of intake air can be handled. high output can be ensured.

In the flow of intake air in both intake passages 20 and 30 shown above, in the low intake air amount region when the switching valve 33 is closed, air flows from the secondary intake passage 30 to the primary intake passage 20 through the communication passage 40. Since the communication path 4
The intake pressure at 0 indicates the combined intake pressure within the primary intake passage 20 and the secondary intake passage 30. Further, even in a predetermined high intake air amount region where the switching valve 33 is open, the intake pressure detected in the communication passage 40 indicates the combined intake pressure of the primary intake passage 20 and the secondary intake passage 30. Therefore, regardless of whether the switching valve 33 is opened or closed, the intake pressure in the communication passage 40 detected by the pressure sensor 51 is always the same as that of the primary intake air that is supplied to the engine after passing through the primary intake passage 20 and the secondary intake passage 30. It shows the composite intake pressure in the intake passage 20 and the secondary intake passage 30, and its characteristic with respect to the intake air amount of the engine is expressed by one characteristic in the entire operating range. Furthermore, when the switching valve 33 operates from closed to open, that is, the intake air to the engine 10 is transferred to the primary intake passage 2.
Even in the transition period when the supply changes from only 0 to the supply through both the primary intake passage 20 and the secondary intake passage 30, the communication passage 40 is always operated from both the primary intake passage 20 and the secondary intake passage 30. Since the composite intake pressure is shown based on the received intake pressure, the effect of fluctuations on the intake pressure due to changes in air flow is small, and the intake pressure can be detected accurately without erroneously detecting it.

Next, FIG. 3 shows a flowchart for performing fuel injection control based on the intake pressure detected by the pressure sensor 51 in the communication passage 40. In the figure, after starting, first, in step S1, various signals for detecting the operating state of the engine are read, and then, in step S2, the intake pressure, that is, the boost P detected by the pressure sensor 51 is read. Then, in step S3, it is determined whether the switching valve 33 is open. This determination is made from the map of the operating range that determines the opening and closing of the switching valve 33 shown in FIG. If it is being performed in the passageway 30, the process advances to step S4. Then, in step S4, based on the boost P read in step S2, the primary injector 23
and the basic injection pulse radiation T of the secondary injector 34
PI and TSI are calculated and the process proceeds to step S5.

In step S5, it is determined whether or not it is fuel injection timing. If the answer is No, which is not the injection timing, the process ends. On the other hand, if the answer is YES, which is the injection timing, the process proceeds to step S6. Then, in step S6, the TPl and TSI obtained in step S4 are corrected in accordance with the operating state at that time, and fuel is injected from the primary injector 23 and the secondary injector 34 based on them, and the process ends. On the other hand, if No in step S3, that is, if the switching valve 33 is closed and air is being supplied to the engine only through the primary intake passage 20, the process advances to step S7. Based on the boost P, the basic injection pulse width TP2 of the primary injector 23 is calculated, and the process proceeds to the next step S8. In step S8, it is determined whether or not it is the fuel injection timing.
If o, the process ends, but if the injection timing is YES, the process proceeds to step S9. Then, in step S9, the basic injection pulse width Tρ2 obtained in step S7 is corrected in accordance with the operating state at that time, and fuel is injected from the primary injector 23 based on the correction, and the process ends.

In the above flow, the boost P is used as it is without correcting its value by opening or closing the switching valve 33, since the characteristic with respect to the intake air amount to the engine is expressed by one characteristic in the entire operating range. The basic injection pulse width of the injector can be determined by

Therefore, based on the intake pressure detected in the communication passage 40, simple and accurate fuel injection control can be performed.

(Effects of the Invention) As described above, according to the engine intake pressure detection device of the present invention, the intake pressure detection means detects the intake pressure in the communication passage that communicates the primary intake passage and the secondary intake passage, which are independent from each other. Since the system is equipped with a The intake pressure corresponding to the intake air amount can be detected.

[Brief explanation of drawings]

Fig. 1 to Fig. 3 show an embodiment of the present invention, Fig. 1 is a schematic diagram of the overall configuration, Fig. 2 is a map showing the control area of the switching valve, and Fig. 3 shows the control of the control unit. It is a flowchart figure. The figure is a characteristic diagram of intake pressure in a conventional example. 10...Rotary piston engine 20...Primary intake passage 22...Primary control valve 30...Secondary intake passage 32...Secondary control valve 33...Switching valve 40...Communication passage 50...・Control unit 51...Pressure sensor (intake pressure detection means) 4th patent applicant Mazda Corporation representative
Patent attorney front 1) Hiroshi 1 person Figure 2 Warm air Fi, 77 Figure 4

Claims (1)

[Claims] (1) A primary intake passage and a secondary intake passage which are independent from each other for supplying intake air to the engine, and a primary control that is provided in the primary intake passage and the secondary intake passage, respectively, and that adjusts the amount of intake air supplied to the engine in conjunction with each other. a valve, a secondary control valve, a switching valve that is provided downstream of the secondary control valve in the secondary intake passage and opens in a predetermined high intake air amount region, and a part downstream of the primary control valve of the primary intake passage; An engine characterized by comprising: a communication passage communicating between the secondary control valve and the switching valve of the secondary intake passage, and an intake pressure detection means for detecting intake pressure in the communication passage. Intake pressure detection device.