JPS5841223A - Intake apparatus for supercharged engine - Google Patents

Abstract

PURPOSE:To improve the durability of a supercharger and to increase the engine output, by providing a trouble detecting means for detecting the fact that a subsidiary throttle valve is kept open by some trouble and a supercharging pressure restricting means operated when said trouble detecting means detects occurrence of trouble with the subsidiary throttle valve for keeping the supercharging pressure lower than a prescribed value. CONSTITUTION:The intake system of an engine 1 is constituted by a main intake system 2 having a main throttle valve 10 and a subsidiary intake system 5 having a subsidiary throttle valve 20 and a supercharger 18. If the subsidiary throttle valve 20 is kept colsed by some trouble, a sensor 37 is turned ON and a supercharging pressure restricting means 35 is turned OFF in response to the output of the trouble detecting means 34. Further, transmission of a clutch signal from a potentiometer 32 to an electromagnetic clutch 26 is interrupted, so that operation of the supercharger 18 is stopped. Through employment of such an arrangement, it is enabled to prevent degradation in durability of the supercharger 18 and drop of the engine output due to driving of the supercharger 18 under a high supercharging pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a turbocharged engine. It consists of a main intake system that supplies fresh air and an auxiliary intake system that is equipped with a supercharger.When the load is below the set engine load, fresh air is supplied from the main intake system, and when the load is above the set engine load, fresh air is supplied from the main intake system. In addition to this, supercharging air is supplied from the auxiliary intake system at least during the compression stroke. ;3;-/373/'it is also known.

However, the main intake system is equipped with a main throttle valve, and the auxiliary intake system is equipped with a sub-throttle valve, which are configured to control the flow rates of fresh air and supercharging air, respectively.
In the auxiliary intake system, when the auxiliary throttle valve operates normally, supercharged air is supplied to the combustion chamber of the engine, and the supercharging pressure upstream of the auxiliary throttle valve during supercharging is suppressed to a predetermined value or less. Yes, the auxiliary throttle valve must be closed only during non-supercharging to prevent the air-fuel mixture from flowing back from the combustion chamber to the auxiliary intake system.

However, if an abnormality occurs in the operating mechanism of the sub-throttle valve, for example, the link connecting the main throttle valve and the sub-throttle valve may come off, causing the sub-3□7.7 total. , 8
．． l, yut, 4. Eh, 8, i. . 2 system is s2 during supercharging
The supercharging pressure upstream of the sub-throttle valve increases, and the supercharging pressure exceeds a predetermined value. Therefore, in this case, the load on the supercharger becomes high and the driving torque becomes large, which may cause a failure of the supercharger driving means, or if the supercharger is driven by the rotation of the engine's drive shaft. This results in problems such as an increase in engine load, resulting in a decrease in engine output, and further damage to the supercharger itself due to an increase in temperature.

In view of the above, the present invention provides an abnormality detection device for detecting the auxiliary throttle valve being left closed due to an abnormality, and an abnormality detection device that receives the output of the abnormality detection device and suppresses the boost pressure upstream of the auxiliary throttle valve to a predetermined value or less. Provided is an intake system for a supercharged engine equipped with a boost pressure suppression device, and the structure of the present invention can be used to solve problems such as reduced durability of the supercharger and reduced engine output due to abnormality of the sub-throttle valve. Examples will be described based on the drawings.

In FIG. 1, 1 is an engine, 2 is a main intake system that supplies fresh air to the engine 1 via a main intake boat 4 that opens into the combustion chamber 5 of the engine 1, and 5 is an auxiliary intake that opens into the combustion chamber 5. 7 is an auxiliary intake system that supplies supercharging air to the engine 1 through 6t, and an exhaust system 7 that discharges exhaust gas from the engine 1 through an exhaust boat 8 that opens into the combustion chamber 5.

In the main intake system 2, 9 is a main intake valve that opens and closes the main intake boat 4 at predetermined timing, 1o is a main throttle valve that is interposed in the middle of the main intake passage 11 and controls the intake flow rate, and 12
1S is a fuel injection nozzle that injects fuel upstream of the main throttle valve 1o, and an injection control device that controls the fuel injection amount.

The injection control device 15 receives the intake air amount signal detected by the air flow meter 14, the engine rotation speed signal detected by the rotation sensor 15, etc., and adjusts the fuel injection amount according to the operating state of the engine 1 based on these signals. It is configured to calculate and issue a control signal to the fuel injection nozzle 12 to inject a predetermined amount of fuel into the main intake system 2.

In the auxiliary intake system 5, 16 is an auxiliary intake valve that opens and closes the auxiliary intake boat 6 at a predetermined timing, which will be described later, by a timing cam 17, and 18 is a supercharger consisting of a vane-type air pump interposed in the middle of the auxiliary intake passage 19. , 20 are auxiliary throttle valves installed downstream of the supercharger 18. Furthermore, 21 is a relief passage that bypasses the supercharger 18, and 22 is a relief valve installed in the relief passage 21, which regulates the upper limit of the supercharging pressure downstream of the supercharger. In the exhaust system 7, the reference numeral 25 is a viewing valve that opens and closes the exhaust boat 81 at predetermined timing, and the reference numeral 24 is an exhaust passage communicating with the exhaust boat 8.

The auxiliary intake valve 16 opens from the end of the intake stroke to the compression stroke, and closes at a later time than the main intake valve 9, as shown in FIG. Supercharging air is supplied from the auxiliary intake system 5 to the engine 1 at least during this compression stroke.

The supercharger 18 is linked to an ffi drive shaft 29 of the engine 1 via an electromagnetic clutch 26, a pulley 27, and a belt 28. That is, the piston 50 in the engine 1
The driving force of the drive shaft 29, which is rotationally driven via the connecting rod 51 due to the reciprocating motion of It is configured to control the driving and stopping of 18.

The electromagnetic clutch 26 is connected or disconnected depending on the load of the engine 1, and in this example, it is linked to a potentiometer 52 that detects the opening degree of the main throttle valve 10.
When the load on the engine 1 exceeds a set value, the electromagnetic clutch 26 is connected and drives the supercharger 18.

Note that the electromagnetic clutch 26 may be controlled using other factors such as intake negative pressure.

The sub-throttle valve 20 is linked to the main throttle valve 10 through a link mechanism 55.
It is configured to open from the closed state in conjunction with the opening of 0 to a predetermined opening degree or more. That is, the main throttle valve 10
When the opening reaches a predetermined opening and the engine load exceeds the set value, the supercharger 18 is driven and the auxiliary throttle valve 20 opens. The flow rate of supercharging air is controlled, and when the engine load is less than a set value, that is, when no supercharging is being performed, the sub-throttle valve 20 is closed to completely prevent the backflow of the air-fuel mixture from the combustion chamber 3 of the engine 1 to the auxiliary intake system 5. do.

34 is an abnormality detection device that detects whether or not the sub-throttle valve 20 is fully closed due to an abnormality, and 35 is an abnormality detection device that detects whether or not the sub-throttle valve 20 is fully closed due to an abnormality.
This is a supercharging pressure suppression device that completely suppresses the supercharging pressure upstream of the engine.

The abnormality detection device 54 has an abnormality determination circuit 56 linked to a potentiometer 52 of the main throttle valve 10 and an open/close sensor 57 of the sub-throttle valve 20. That is, in this example, an AND circuit is used as the abnormality determination circuit 36 as shown in FIG.
It is designed to input all the open/close signals from the
When the engine load exceeds the set value, it goes down/John meter '52
Despite the fact that the clutch signal for driving the supercharger 18 is being sent to the electromagnetic clutch 26 from It is designed to output full output.

Then, the supercharging pressure suppressing device 55 has a changeover switch 58 interposed on the connection line connecting the potentiometer 52 and the electromagnetic clutch 26, and the changeover switch! +8 and the abnormality determination circuit 56, that is, an AND circuit, and is configured to turn off the changeover switch 58 upon receiving the output from the AND circuit, thereby closing the sub-throttle valve 2o. The supercharger 18 is stopped when the engine is released.

In the abnormality detection device 54, in this example, the clutch signal from the potentiometer '52 is transferred to the changeover switch 58.
'e I have taken everything before passing, but this is supercharger 1
This is to prevent the operation from becoming unstable when stopping the clutch signal 8, and the clutch signal may be inputted to the total abnormality determination circuit 56 after passing through the changeover switch 58.

Next, to explain the operation of the above embodiment, when the load of 2/J/1 is less than the set value, the supercharger 18 is not driven, and fresh air is combusted only from the main intake system 2 by natural intake. room 6
supplied to At this time, the auxiliary throttle valve 20 closes the auxiliary intake passage 19.

When the load on the engine 1 increases and the main throttle valve 10 is opened wide, that is, when the load on the engine 1 exceeds a set value, the electromagnetic clutch 26 is brought into a connected state by a clutch signal from the bottom/joist meter 52. The supercharger 18 is driven, pressurized air is discharged from the supercharger 18, and the auxiliary throttle valve 20 opens in conjunction with the opening operation of the main throttle valve 10. In addition to fresh air from the auxiliary intake system 5, supercharging air is supplied from the auxiliary intake system 5.

However, if the sub throttle valve 20 is left closed due to a malfunction of the link mechanism 55 that links the main throttle valve 10 and the sub throttle valve 20, the opening/closing sensor 37 is turned on and an abnormality in the sub throttle valve 20 is detected. Device 5
4, the changeover switch 58 of the boost pressure suppression device 35 is turned off in response to the output from the abnormality detection device 34, and the clutch signal sent from the potentiometer 52 to the electromagnetic clutch 26 is interrupted. The operation of the feeder 18 is stopped to prevent the supercharging pressure upstream of the sub-throttle valve from exceeding a predetermined value.

In the above embodiment, an abnormality in the sub-throttle valve 20 is detected based on the signal from the opening/closing sensor 57, but a pressure sensor is provided upstream of the sub-throttle valve 20 to detect the supercharging pressure during supercharging. An abnormality in the sub-throttle valve 20 may be detected from the height. Alternatively, an opening sensor may be provided in the relief valve 22 to detect an abnormality in the sub-throttle valve 20 from the opening degree of the relief valve 22 during supercharging.

In addition to completely stopping the supercharger 18, the supercharging pressure suppressing device 55 may include, for example, means for reducing the rotation of the supercharger 18 according to the capacity of the relief valve 22, or a means for reducing the rotation of the supercharger 18 according to the capacity of the relief valve 22. A bypass passage for bypassing is provided entirely separately, a bypass valve is interposed in the bypass passage, and a sub-throttle valve 20 is installed.
It is also possible to adopt a system in which the bypass valve is opened in the event of an abnormality to suppress the supercharging pressure.

Furthermore, the fuel injection nozzle 12 may be provided separately in the auxiliary intake system 5 in addition to the main intake system 2.
2 may be replaced with a fuel supply device using a carburetor. Furthermore, the supercharger 18 may be driven by other driving means such as an electric motor. Furthermore, in the above embodiment, the backflow of the air-fuel mixture from the combustion chamber 6 to the auxiliary intake system 5 during non-supercharging is prevented by the auxiliary throttle valve 20, but the auxiliary intake valve 16 prevents the mixture from flowing back into the auxiliary intake port 6. The above embodiment can also be applied to rotary piston engines as well as reciprocating engines.

As described above, according to the present invention, an abnormality detection device detects a state in which the sub-throttle valve is left closed due to an abnormality. This provides an excellent effect of eliminating the problem.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention; FIG. 1 is an overall configuration diagram of a supercharged engine, FIG. 2 is a curve diagram showing valve opening/closing timing, and FIG. 3 is an abnormality detection device and a supercharging pressure suppression device. FIG. 1...Engine, 2...Main intake system, 5
...Auxiliary intake system, 7...Exhaust system, 10...
...Main throttle valve, 18...Supercharger, 2
0...Subthrottle valve, 54...Abnormality detection device, 55...Supercharging pressure suppression device Patent applicant
Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] +11 The intake system of the engine is constituted by a main intake system having a main throttle valve and an auxiliary intake system having a sub-throttle valve, and a supercharger is provided in the auxiliary intake system,
When the engine load is below the set load, fresh air is supplied from the main intake system, while when the engine load is above the set load, supercharging air is supplied from the auxiliary intake system at least during the compression stroke in addition to fresh air from the main intake system. In the supercharged engine, the above-mentioned sub-throttle valve is equipped with an abnormality detection device that detects all closing and opening due to an abnormality, and an abnormality detection device that receives the output of the abnormality detection device and suppresses the total supercharging pressure upstream of the above-mentioned sub-throttle valve to a predetermined value or less. An intake system for a supercharged engine, characterized in that it is equipped with a supercharging pressure suppression device.