JP2007224850A - Blow-by gas processing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow-by gas processing device capable of changing a blow-by gas supply passage in accordance with an intake air amount.
A blow-by gas processing device (100) includes a multi-cylinder internal combustion engine, a first valve (5) provided in an intake branch passage (22) of each cylinder of the internal combustion engine, and a first valve. And a second valve (3) provided in the collecting passage (21) in which the intake branch passages are gathered upstream of the intake air required amount detecting means (2) for detecting the intake air required amount of the internal combustion engine. And switching means (9) for switching the supply destination of the blow-by gas generated in each cylinder to the intake system of the internal combustion engine in accordance with the required intake air amount of the internal combustion engine.
[Selection] Figure 1

Description

  The present invention relates to a blow-by gas processing apparatus for a multi-cylinder internal combustion engine having an independent throttle valve.

  In a general internal combustion engine, blow-by gas leaking from the combustion chamber through the gap between the piston and the cylinder wall into the crankcase is generated. The main component of this blow-by gas is unburned gas. Therefore, it is necessary to introduce blow-by gas into each cylinder again and burn it. Therefore, blow-by gas recirculation devices are often attached to internal combustion engines. The blow-by gas is introduced downstream of the throttle valve by the blow-by gas recirculation device.

  By the way, in a multi-cylinder internal combustion engine, a sub-throttle valve may be provided in the intake pipe before branching, and an independent throttle valve may be provided in each intake pipe after branching (for example, Patent Document 1). reference). An internal combustion engine equipped with this independent throttle has high responsiveness to the accelerator opening and is suitable for generating high output.

JP-A-1-224414

  If the return passage of blow-by gas is fixed in a multi-cylinder internal combustion engine provided with an independent throttle valve, variation in the distribution of blow-by gas to each cylinder may occur due to a change in the amount of intake air. For example, the opening of the independent throttle valve is small at a light load such as idling, and the amount of air taken into each cylinder is small.

  An object of this invention is to provide the blow-by gas processing apparatus which can change the supply passage of blow-by gas according to the amount of intake air.

  A blow-by gas processing apparatus according to the present invention includes a multi-cylinder internal combustion engine, a first valve provided in an intake branch passage of each cylinder of the internal combustion engine, and an intake branch upstream of the first valve. A second valve provided in the collective passage that collects the passages, intake air request amount detection means for detecting an intake air request amount of the internal combustion engine, and blow-by gas generated in each cylinder to the intake system of the internal combustion engine Switching means for switching the supply destination according to the intake air requirement amount of the internal combustion engine. In the blow-by gas processing apparatus according to the present invention, the supply destination of the blow-by gas to the intake system is switched by the switching means according to the intake air request amount. Therefore, the blow-by gas supply passage can be switched in accordance with the intake air amount of the internal combustion engine.

  The switching means may supply blow-by gas upstream of the first valve and downstream of the second valve in the intake system when the intake air request amount is less than the threshold value. In this case, the intake passage volume between the second valve and each cylinder is larger than the intake passage volume between the first valve and each cylinder. Occurrence of variations in the distribution amount among the cylinders can be suppressed.

  In the intake system, a surge tank is further provided upstream of the first valve and downstream of the second valve, and the switching means supplies blow-by gas to the surge tank when the intake air requirement is less than a threshold value. May be. In this case, the blow-by gas supplied to the surge tank diffuses uniformly. Thereby, it is possible to suppress the occurrence of variation in the distribution amount of the blow-by gas between the cylinders.

  The switching means may supply blow-by gas downstream of the first valve in the intake system when the intake air request amount is greater than or equal to a threshold value. In this case, the amount of air supplied to each cylinder increases. Thereby, even if the amount of blow-by gas supplied to each cylinder varies, the concentration difference of blow-by gas in each cylinder becomes small. Therefore, it is possible to suppress the occurrence of variation in blowby gas concentration between cylinders. Moreover, since blow-by gas is supplied downstream from the first valve, it is possible to prevent the blow-by gas from being discharged to the outside.

  Control means for controlling the opening degree of the first valve and the second valve may be further provided. Further, the control means may control the opening degree of the first valve to be fully opened when the intake air request amount is less than a threshold value. The control means may control the amount of air supplied to each cylinder by changing the opening of the second valve when the required intake air amount is less than the threshold value. In this case, since the temperature of the air passing through the second valve increases, vaporization of the fuel supplied to each cylinder of the internal combustion engine can be promoted. As a result, the change in torque generated in each cylinder of the internal combustion engine becomes smooth.

  The control means may control the opening degree of the second valve to be fully opened when the intake air request amount is equal to or greater than a threshold value. The control means may control the amount of air supplied to each cylinder by changing the opening of the first valve when the required intake air amount is equal to or greater than a threshold value. In this case, since the temperature of the air passing through the first valve does not rise so much, knocking in each cylinder is improved, and fuel consumption and torque are improved.

  The required air amount detection means may be detection means for detecting the opening of the accelerator. The switching unit may include a recovery unit that collects blow-by gas and a switching valve that switches a supply destination of blow-by gas.

  According to the present invention, the supply passage of blow-by gas can be switched according to the intake air amount of the internal combustion engine.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic diagram showing an overall configuration of a blow-by gas processing apparatus 100 according to a first embodiment of the present invention. As shown in FIG. 1, the blow-by gas processing apparatus 100 includes an air cleaner 1, an air flow meter 2, a sub-throttle valve 3, a surge tank 4, a plurality of independent throttle valves 5, a plurality of injectors 6, a cylinder head 7, a PCV (Positive Crankcase). Ventilation) valve 8, switching valve 9, control unit 10, and accelerator opening sensor 11 are included.

  The air cleaner 1 includes an air cleaner element that traverses an internal intake passage. One end of the air cleaner 1 communicates with the outside air, and the other end of the air cleaner 1 communicates with the surge tank 4 via the pipe 21. The air flow meter 2 and the sub throttle valve 3 are inserted in the pipe 21. The air flow meter 2 is disposed closer to the air cleaner 1 than the sub-throttle valve 3. The sub-throttle valve 3 is composed of a butterfly valve, for example.

  The surge tank 4 and the cylinder head 7 are connected by a plurality of intake pipes 22. The independent throttle valve 5 and the injector 6 are inserted in each intake pipe 22 one by one. The independent throttle valve 5 is disposed closer to the surge tank 4 than the injector 6. The independent throttle valve 5 is a butterfly valve, for example. The PCV valve 8 is provided in the cylinder head 7. The PCV valve 8 is connected to the inlet of the switching valve 9 via a pipe 23.

  The switching valve 9 is composed of a three-way valve or the like. One outlet of the switching valve 9 is connected to the surge tank 4 via a pipe 24. The other outlet of the switching valve 9 is connected to each of the intake pipes 22 via pipes 25 branched into a plurality of pipes. Each intake pipe 22 and pipe 25 are connected between the independent throttle valve 5 and the injector 6. The accelerator opening sensor 11 is a sensor for detecting the accelerator opening.

  The control unit 10 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like. The control unit 10 controls the sub-throttle valve 3, the independent throttle valve 5, the injector 6, and the switching valve 9 based on the detection results of the air flow meter 2 and the accelerator opening sensor 11. Details will be described later.

  Next, an outline of the operation of the blow-by gas processing apparatus 100 will be described. First, the air taken into the air cleaner 1 is purified by the air cleaner element and supplied to the pipe 21. The air flow meter 2 detects the amount of air flowing through the pipe 21 and gives the detection result to the control unit 10. The sub-throttle valve 3 changes the opening according to an instruction from the control unit 10. Thereby, the amount of air flowing through the pipe 21 can be adjusted. The air that has passed through the sub-throttle valve 3 is temporarily stored in the surge tank 4 and then supplied to the plurality of intake pipes 22.

  The independent throttle valve 5 changes the opening according to an instruction from the control unit 10. Thereby, the amount of air flowing through each intake pipe 22 can be adjusted. The air that has passed through the independent throttle valve 5 is supplied to each cylinder (not shown) via the cylinder head 7. Further, the injector 6 supplies an amount of fuel necessary for combustion in each cylinder to each cylinder via the cylinder head 7 in accordance with an instruction from the control unit 10.

  The PCV valve 8 opens and closes according to instructions from the control unit 10. When the PCV valve 8 is opened, the cylinder head 7 and the pipe 23 communicate with each other. Thereby, blow-by gas is supplied to the switching valve 9. The switching valve 9 switches communication between the pipe 23 and the pipe 24 or communication between the pipe 23 and the pipe 25 in accordance with an instruction from the control unit 10. Accordingly, blow-by gas is supplied to the surge tank 4 or the intake pipe 22 in accordance with the operation of the switching valve 9. The accelerator opening sensor 11 detects the opening of the accelerator and gives the detection result to the control unit 10.

  Hereinafter, details of the control by the control unit 10 will be described. The control unit 10 determines whether the required air amount of the internal combustion engine including the cylinder head 7 is small. For example, when the accelerator opening is smaller than a predetermined value, it can be determined that the required air amount is small. In the present embodiment, the control unit 10 determines that the required air amount is small if the accelerator opening is less than the threshold value based on the detection result of the accelerator opening sensor 11. This threshold is, for example, about 10 ° to 20 °.

  If the accelerator opening is equal to or greater than the threshold value, the control unit 10 controls the sub-throttle valve 3 to fully open the sub-throttle valve 3 and controls the switching valve 9 to connect the pipe 23 and the pipe 25. . In addition, the control unit 10 controls the independent throttle valve 5 to supply an amount of air necessary for combustion in each cylinder to each cylinder.

  In this case, the amount of air supplied to each cylinder increases. Thereby, even if the amount of blow-by gas supplied to the pipe 25 varies, the difference in the concentration of blow-by gas in each cylinder becomes small. Even when the sub-throttle valve 3 is fully open, the blow-by gas is supplied downstream from the independent throttle valve 5, so that the blow-by gas can be prevented from being discharged to the outside. Further, since the cylinder intake air temperature after passing through the independent throttle valve 5 does not rise so much, knocking is improved and fuel efficiency and torque are improved.

  If the accelerator opening is less than the threshold value, the control unit 10 controls the independent throttle valve 5 to fully open the independent throttle valve 5 and controls the switching valve 9 to connect the pipe 23 and the pipe 24. . Further, the control unit 10 controls the sub-throttle valve 3 to supply an air amount necessary for combustion in each cylinder to each cylinder.

  In this case, since the volume between the sub-throttle valve 3 and the cylinder is larger than the volume between the independent throttle valve 5 and the cylinder, the blow-by gas diffuses uniformly. In particular, blow-by gas supplied to the surge tank 4 before branching to the intake pipe 22 diffuses uniformly in the surge tank 4. Thereby, even if the amount of air supplied from the sub-throttle valve 3 to the surge tank 4 is small, the blow-by gas can be uniformly distributed to each cylinder. In this case, since the amount of air supplied to each cylinder is reduced, the opening of the sub-throttle valve 3 is reduced. Therefore, discharge of blow-by gas to the outside can be prevented. Furthermore, since the intake air temperature after passing through the sub-throttle valve 3 rises, the vaporization of the fuel supplied from the injector 6 can be promoted. As a result, the torque change generated in each cylinder becomes smooth.

  FIG. 2 is an example of a flowchart when the control unit 10 controls each unit. The control unit 10 executes the following flowchart at a predetermined cycle. First, the control part 10 determines whether an accelerator opening is more than a threshold value (step S1). In this case, the control unit 10 determines based on the detection result of the accelerator opening sensor 11. When it is determined in step S1 that the accelerator opening is equal to or larger than the threshold value, the control unit 10 controls the sub-throttle valve 3 to fully open the sub-throttle valve 3, and controls the switching valve 9 to control the piping 23. And the pipe 25 are communicated (step S2). Thereby, blow-by gas can be supplied to the downstream side of the independent throttle valve 5. Next, the control unit 10 controls the independent throttle valve 5 to supply an amount of air necessary for combustion in each cylinder to each cylinder (step S3). Thereafter, the control unit 10 ends the operation.

  If it is not determined in step S1 that the accelerator opening is equal to or greater than the threshold value, the control unit 10 controls the independent throttle valve 5 to fully open the independent throttle valve 5 and controls the switching valve 9 to perform piping. 23 and the piping 24 are communicated (step S4). Thereby, blow-by gas can be supplied to the downstream side of the sub-throttle valve 3. Next, the control unit 10 controls the sub-throttle valve 3 to supply an amount of air necessary for combustion in each cylinder to each cylinder (step S5). Thereafter, the control unit 10 ends the operation.

  As described above, according to the flowchart of FIG. 2, even when the air supply amount is small at the time of idling or the like, it is possible to suppress the occurrence of variation in the distribution amount of the blow-by gas between the cylinders.

  In this embodiment, the independent throttle valve 5 corresponds to the first valve, the sub-throttle valve 3 corresponds to the second valve, the air flow meter 2 corresponds to the air demand amount detection means, and the switching valve 9 Corresponds to the switching means, the control unit 10 corresponds to the control means, the accelerator opening sensor 11 corresponds to the detection means, the PCV valve 8 corresponds to the recovery means, the pipe 21 corresponds to the collecting passage, and the intake pipe Reference numeral 22 corresponds to an intake branch passage.

It is a schematic diagram which shows the whole structure of the blowby gas processing apparatus which concerns on 1st Example of this invention. It is an example of the flowchart at the time of a control part controlling each part.

Explanation of symbols

3 Sub-throttle 4 Surge tank 5 Independent throttle 7 Cylinder 8 PCV valve 9 Three-way valve 10 Control unit 11 Accelerator opening sensor 100 Blow-by gas processing device

Claims (11)

A multi-cylinder internal combustion engine;
A first valve provided in an intake branch passage of each cylinder of the internal combustion engine;
A second valve provided in a collecting passage that is upstream of the first valve and collects the intake branch passage;
An intake air request amount detection means for detecting an intake air request amount of the internal combustion engine;
A blow-by gas processing apparatus, comprising: switching means for switching a supply destination of the blow-by gas generated in each cylinder to the intake system of the internal combustion engine in accordance with a required intake air amount of the internal combustion engine. The switching means supplies the blow-by gas upstream of the first valve and downstream of the second valve in the intake system when the intake air demand is less than a threshold value. The blow-by gas processing apparatus according to claim 1. A surge tank further upstream of the first valve and downstream of the second valve in the intake system;
The blow-by gas processing apparatus according to claim 2, wherein the switching means supplies the blow-by gas to the surge tank when the intake air requirement amount is less than the threshold value. The switching means supplies the blow-by gas downstream of the first valve in the intake system when the intake air requirement is equal to or greater than a threshold value. The blowby gas processing apparatus in any one. The blow-by gas processing apparatus according to any one of claims 1 to 4, further comprising control means for controlling the opening degree of the first valve and the second valve. The blow-by gas processing apparatus according to claim 5, wherein the control unit controls the opening degree of the first valve to be fully opened when the intake air request amount is less than the threshold value. The control means controls the amount of air supplied to each of the cylinders by changing the opening of the second valve when the required intake air amount is less than the threshold value. Item 7. The blowby gas processing apparatus according to Item 5 or 6. The blow-by gas according to any one of claims 5 to 7, wherein the control means controls the opening degree of the second valve to be fully opened when the intake air request amount is equal to or greater than the threshold value. Processing equipment. The control means controls the amount of air supplied to each of the cylinders by changing an opening of the first valve when the required intake air amount is equal to or greater than the threshold value. Item 9. The blow-by gas processing apparatus according to any one of Items 5 to 8. The blow-by gas processing apparatus according to any one of claims 1 to 9, wherein the intake air demand amount detection means is detection means for detecting an opening degree of an accelerator. The blow-by gas processing apparatus according to claim 1, wherein the switching unit includes a recovery unit that collects the blow-by gas and a switching valve that switches a supply destination of the blow-by gas.

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