JPH084585Y2 - Intake pressure detection device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an intake pressure detection device for an internal combustion engine mainly used in automobiles.

[Prior Art] Generally, in an automobile engine, a pressure sensor is connected to an intake passage of the engine through a branch passage, and a filter is provided in the branch passage to trap foreign matter floating in intake air. I have to. However, the eyes of the filter are
Generally, a relatively coarse selection is made on the premise that solid foreign matter or the like can be prevented from adhering to the rubber diaphragm or the like of the pressure sensor and that delay of pressure propagation can be avoided. Therefore, it reliably captures foreign substances such as oil vapor and fuel vapor mixed in the intake air through the blow-by gas recirculated to the intake passage, or oil vapor mixed in the intake air from the bearing part of the supercharger. Difficult to do. In particular, when such foreign matter is carried to a recent pressure sensor using a semiconductor or the like, not only is it deteriorated at an early stage, but also the intake pressure may be erroneously detected.

In order to solve such a problem, the middle of the branch passage is formed in a labyrinth, or as a prior art of the present invention, for example, as shown in Japanese Utility Model Laid-Open No. 62-35244,
There is also one in which a migratory portion is provided in the middle of the branch passage.

[Problems to be Solved by the Invention] With such a configuration, it is possible to prevent oil vapor, fuel vapor, etc. in intake air from adhering to the inner wall surface of the branch passage and being directly carried to the pressure sensor. However, there is a possibility that foreign matter adhering to the inner wall surface may be carried to the pressure sensor side together with the pulsation of intake air, and thus there is a surface lacking in certainty. Moreover, with such a configuration, the branch passage becomes relatively long and the internal structure of the passage becomes complicated, so that the propagation of intake pressure is delayed and the cost is increased.

Further, in the case where the inside of the intake passage and the pressure receiving portion of the pressure sensor are directly communicated with each other via the branch passage, the intake pulsation easily acts on the pressure sensor, so that the risk of detecting the intake pulsation also increases. .

The object of the present invention is to eliminate such problems all at once.

[Means for Solving the Problems] In order to achieve the above object, the present invention is an internal combustion engine that includes an actuator having a diaphragm chamber that communicates with an intake passage and a pressure sensor that detects intake pressure. In the engine, the pressure receiving portion of the pressure sensor is communicated with the diaphragm chamber, and the intake pressure of the intake air expanded in the diaphragm chamber is detected.

[Operation] According to such a configuration, since the intake pressure is taken out through the diaphragm chamber of the actuator, a special branch passage for directly communicating the inside of the pressure sensor with the intake passage is unnecessary. Moreover, since the diaphragm chamber of the actuator has a function of expanding the intake air, even if foreign matter such as oil vapor or fuel vapor is carried into the diaphragm chamber from the intake passage, these foreign matter will be introduced into the diaphragm chamber. Will be separated from the intake air by expansion at. For this reason, it becomes difficult for foreign matter in the intake air to be carried from the diaphragm chamber into the pressure sensor.

Further, in the diaphragm chamber, the intake pulsation is suppressed by the diaphragm vibration of the diaphragm and the like, so that the intake pulsation hardly acts on the pressure sensor.

As the actuator, for example, an actuator for supercharging pressure control that opens and closes a wastegate valve of a supercharger, an actuator for adjusting ignition timing provided in association with a distributor, or the like, and the intake pressure is used. Various actuators described above can be used.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

The drawing schematically shows an intake system of a diesel engine 1 which is an internal combustion engine. The diesel engine 1 includes an exhaust turbine-type supercharger 4 that supercharges intake air into a combustion chamber through an intake passage 3 formed inside an intake manifold 2, and an intake air compressed by the supercharger 4. A pressure sensor 5 for detecting the supercharging pressure is provided. The supercharger 4 is the same as the normal one, and is provided with a compressor 8 installed in the intake passage 3 coaxially with the exhaust turbine 7 installed in the exhaust passage 6. The compressor 8 rotates as the exhaust turbine 7 rotates. Is configured to rotate to compress the intake air. A bypass passage 9 that bypasses the exhaust turbine 7 is provided on the exhaust turbine 7 side, and a waste gate valve 10 is provided at the turbine inlet portion of the bypass passage 9. Then, the waste gate valve 10 is opened and closed by the boost pressure control actuator 11 to prevent the boost pressure from exceeding the set pressure.

The actuator 11 has a diaphragm chamber 13 communicating with the intake passage 3 through a pressure guiding passage 12 and an atmosphere chamber 15 side containing a spring 14, which are separated from each other by a diaphragm 16. The waste gate valve 10 is connected via a rod 17 or the like, and the waste gate valve 10 is opened and closed by moving the rod 17 forward and backward.

The pressure sensor 5 uses, for example, a thin film diaphragm made of a semiconductor or a metal as a pressure receiving portion (not shown), so that the strain displacement or the like can be converted into an electric signal to detect the intake pressure. It has become.

The pressure receiving portion of the pressure sensor 5 and the diaphragm chamber 13 of the actuator 11 are communicated with each other via the boost pressure detecting passage 18 to form an intake pressure detecting device 19 according to the present invention. The supercharging pressure outlet 18a of the supercharging pressure detection passage 18 is located at a position higher than the supercharging pressure introducing port 12a of the pressure guiding passage 12 that is opened in the center of the diaphragm chamber 13, and is opened at the top of the diaphragm chamber 13. At the same time, it is projected inward from the inner wall surface 13a.

With such a configuration, the supercharging pressure is guided to the pressure sensor 5 via the diaphragm chamber 13 of the actuator 11. Then, since the intake air is expanded in the diaphragm chamber 13 and the pulsation of the intake air is suppressed by the membrane vibration of the diaphragm 16, it is originally difficult for oil vapor or fuel vapor to enter through the pressure guiding passage 12. It is in. In addition, even if the diaphragm chamber is
Even if oil vapor, fuel vapor, and the like are carried to 13, the foreign matters are separated from the intake air by expansion in the diaphragm chamber 13, and flow downward through the inner wall surface 13a and the like. Moreover, since the supercharging pressure outlet 18a of the supercharging pressure detection passage 18 is projected more inward than the inner wall surface 13a of the top of the diaphragm chamber 13, oil, fuel, etc. adhering to the inner wall surface 13a of the diaphragm chamber 13 Are not transported to the pressure sensor 5.

Therefore, according to the above configuration, it is possible to effectively prevent foreign substances such as oil vapor and fuel vapor that are mixed together during intake from being conveyed to the pressure sensor 5. That is, since the pressure of clean intake air can be applied to the pressure receiving portion of the pressure sensor 5, early deterioration of the pressure sensor 5 due to foreign matter can be prevented, and erroneous detection of boost pressure can be prevented.
Moreover, in the diaphragm chamber 13, since the intake pulsation is suppressed by the membrane vibration of the diaphragm 16, there is also an advantage that erroneous detection of the boost pressure due to the intake pulsation can be prevented.

Further, the pressure receiving portion of the pressure sensor 5 is communicated with the diaphragm chamber 13 of the actuator 11 for controlling the supercharging pressure, and since foreign matter in the intake air is separated in the diaphragm chamber 13, the pressure receiving portion is connected to the intake passage 3 It is possible to eliminate special branch passages and filters for communicating with the. Therefore, the structure of the intake pressure detection device 19 itself can be simplified without difficulty, and the cost can be reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to a diesel engine and a supercharged engine, but can be suitably applied to a gasoline engine or the like.

In addition, when opening the boost pressure outlet of the boost pressure detection passage at a location other than the top of the diaphragm chamber, make sure that it does not protrude from the inner wall surface of the diaphragm chamber from the viewpoint of effectively preventing foreign matter from entering. It is desirable to keep it.

Further, the actuator is not limited to the one for controlling the boost pressure, but the actuator for adjusting the ignition timing provided in association with the distributor, the actuator for the throttle positioner that adjusts the opening of the throttle valve by the intake pressure, etc. It is possible to use various actuators that operate by intake pressure.

[Effects of the Invention] As described above, in the present invention, the intake pressure is detected from the diaphragm chamber of the existing actuator that uses the intake pressure, so that the intrusion of foreign matter into the pressure sensor and the intake pulsation are effective. It is possible to prevent it, and the structure can be simplified without difficulty. For this reason, the durability of the pressure sensor is improved, and it is possible to provide an intake pressure detection device for an internal combustion engine that can detect the intake pressure almost accurately over a long period of time and that can reduce the cost.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a partial sectional view schematically showing the whole, and FIG. 2 is an enlarged sectional view showing a portion A of FIG. 1 ... Internal combustion engine (diesel engine) 3 ... Intake passage 4 ... Supercharger 5 ... Pressure sensor 11 ... Actuator 12 ... Pressure passage 12a ... Supercharging pressure inlet 13 ... Diaphragm chamber 13a ... Inner wall surface 18 ... Supercharging pressure detection Passage 18a ... Supercharging pressure outlet 19 ... Intake pressure detection device

Claims (1)

[Scope of utility model registration request] 1. An internal combustion engine comprising an actuator having a diaphragm chamber communicating with an intake passage and a pressure sensor for detecting intake pressure, wherein a pressure receiving portion of the pressure sensor is communicated with the diaphragm chamber. The intake pressure detecting device for an internal combustion engine is characterized in that the intake pressure of the intake air expanded in the diaphragm chamber is detected.