Engine system

Abstract

To provide an engine system that suppresses ejection of oil from an oil separator while securing recirculation of blow-by gas to an intake system.SOLUTION: An engine system includes: an engine; an oil separator in which oil separated from blow-by gas generated in the engine and recirculated to an intake system is retained; a pump for sucking the oil in the oil separator; piping that communicates the oil separator and the pump; an on-off valve for opening / closing the piping; and a control device that controls an operation of the on-off valve. The control device opens the on-off valve when a predetermined time corresponding to an operating state of the engine elapses with the on-off valve closed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an engine system. [Background technology]

[0002] There is known an engine equipped with an oil separator, in which oil separated from blow-by gas that is generated within the engine and recirculated to the intake system is stored (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-181779 A Summary of the Invention [Problem to be solved by the invention]

[0004] If oil accumulates in the oil separator, it may spray out of the oil separator. The sprayed oil may be stirred up by the blow-by gas and carried to the intake system of the engine. Therefore, it is considered to provide a pump to suck the oil from the oil separator. However, if oil is constantly sucked from the oil separator, the blow-by gas in the oil separator may also be sucked in by the pump, which may hinder the return of the blow-by gas to the intake system.

[0005] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an engine system that suppresses the ejection of oil from an oil separator while ensuring the recirculation of blow-by gas to the intake system. [Means for solving the problem]

[0006] The above object can be achieved by an engine system comprising an engine, an oil separator in which oil separated from blow-by gas generated within the engine and returned to an intake system is collected, a pump for sucking oil from the oil separator, piping connecting the oil separator and the pump, an on-off valve for opening and closing the piping, and a control device for controlling the operation of the on-off valve, wherein the control device opens the on-off valve when a predetermined time corresponding to the operating state of the engine has elapsed with the on-off valve closed. Effect of the Invention

[0007] According to the present invention, it is possible to provide an engine system that suppresses the ejection of oil from an oil separator while ensuring the recirculation of blow-by gas to an intake system. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1A is a schematic diagram of an engine system, and FIG. 1B is a schematic diagram of an oil separator. [Diagram 2] FIG. 2 is a flowchart illustrating an example of the opening and closing control of the switching valve executed by the ECU. [Diagram 3] FIG. 3 is a view showing an example of a map showing the jetting region. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Engine outline] FIG. 1A is a schematic diagram of an engine system A. The engine system A includes an engine 1 and an ECU (Electronic Control Unit) 50. The engine 1 is a V-type engine. The engine 1 has a pair of banks 2L and 2R protruding in a V-shape from an upper portion of a cylinder block 6. The engine system A is mounted on, for example, a vehicle. The bank 2L includes a cylinder head 5L and a head cover 4L. Similarly, the bank 2R includes a cylinder head 5R and a head cover 4R. The cylinder heads 5L and 5R are disposed on an upper portion of the cylinder block 6. The head cover 4L is disposed on an upper portion of the cylinder head 5L. Similarly, the head cover 4R is disposed on an upper portion of the cylinder head 5R.

[0010] A plurality of cylinders are provided in each of the banks 2L and 2R in the cylinder block 6. A piston is provided in each cylinder. Each piston is connected to a crankshaft 8 so as to transmit power. A ladder frame 7 is attached to the lower side of the cylinder block 6. The crankshaft 8 is rotatably supported by the cylinder block 6 and the ladder frame 7. A crank chamber 6a that houses the crankshaft 8 is defined inside the cylinder block 6 and the ladder frame 7. An oil pan 9 that stores oil for lubrication is attached to the lower side of the ladder frame 7. The oil stored in the oil pan 9 is supplied to each sliding part of the engine 1 by a pump (not shown). The oil used for lubrication finally flows down to the oil pan 9.

[0011] The ECU 50 is mainly composed of a computer including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and other volatile and non-volatile memories. An ignition switch 61, a crank angle sensor 62, and an air flow meter 63 are connected to the ECU 50. The ignition switch 61 detects the on / off state of the ignition. The crank angle sensor 62 detects the crank angle of the engine 1. The air flow meter 63 detects the intake air amount of the engine 1. The ECU 50 calculates the rotation speed and the load of the engine 1 based on the crank angle and the intake air amount, respectively. The ECU 50 controls the fuel injection amount and the intake air amount of the engine 1 based on the rotation speed and the load of the engine 1. The ECU 50 is an example of a control device.

[0012] [Outline of oil separator configuration] FIG. 1B is a schematic diagram of the oil separator 10R. FIG. 1B shows the internal configuration of the oil separator 10R. The oil separator 10R is integrally formed on the upper surface 4Ra of the head cover 4R. The oil separator 10R includes a housing 11 provided on the upper surface 4Ra of the head cover 4R. The housing 11 is formed with an inlet 12a and an outlet 12b. The outlet 12b is located above the inlet 12a in the direction of gravity. A blow-by gas supply pipe 22 is connected to the housing 11. The blow-by gas supply pipe 22 is connected to the housing 11 at a position above the inlet 12a in the direction of gravity.

[0013] The blow-by gas is introduced into the housing 11 from the crank chamber 6a through the inlet 12a. As the blow-by gas flows through the housing 11, it collides with the inner wall surface of the housing 11. As a result, the oil contained in the blow-by gas is captured on the inner wall surface. In this way, the oil is separated from the blow-by gas in the housing 11. The blow-by gas from which the oil has been separated is returned to the intake system of the engine 1, for example, a surge tank, through the blow-by gas supply pipe 22. The oil adhering to the inner wall surface of the housing 11 flows down due to the vibration of the engine 1 and the action of gravity, and accumulates in the lower part of the housing 11. The oil accumulated in the housing 11 flows from the outlet 12b through oil passages formed in the cylinder head 5R and the cylinder block 6 due to its own weight to the oil pan 9.

[0014] As shown in FIG. 1B, one end of the discharge pipe 24 is connected to the lower part of the housing 11. In detail, one end of the discharge pipe 24 is connected to a portion in the housing 11 where oil is accumulated. The other end of the discharge pipe 24 is connected to a scavenging pump 40. A switching valve 30 is provided in the discharge pipe 24. The discharge pipe 24 is an example of a pipe. The switching valve 30 is an example of an opening / closing valve. A communication pipe 44 that communicates with the oil pan 9 is connected to the scavenging pump 40. The scavenging pump 40 is provided to convey oil accumulated in, for example, a cam chamber (not shown) to the oil pan 9 via the communication pipe 44. The scavenging pump 40 is a mechanical pump that is driven in conjunction with the rotation of the crankshaft 8. Therefore, the scavenging pump 40 is always driven while the engine 1 is running.

[0015] As described above, oil accumulates in the housing 11 of the oil separator 10R. When the flow rate of oil separated from the blow-by gas in the housing 11 is greater than the flow rate of oil discharged from the discharge port 12b, the oil accumulates in the housing 11. If the amount of oil in the housing 11 increases, the oil may gush out from the inlet port 12a. Therefore, the ECU 50 opens the switching valve 30 at a predetermined timing, which will be described in detail later. As a result, the oil accumulated in the housing 11 is sucked by the scavenging pump 40. As a result, the oil is forcibly transported to the oil pan 9, and the above-mentioned gush out of the oil is suppressed.

[0016] Here, in order to suppress the oil from spouting from the oil separator 10R, for example, it is conceivable to enlarge the discharge port 12b. However, if the discharge port 12b is enlarged, there is a risk that blow-by gas will flow into the housing 11 from the discharge port 12b. This may reduce the flow rate of the blow-by gas passing through the housing 11, and the oil may not be sufficiently separated from the blow-by gas. In addition, there is a risk that ventilation in the crank chamber 6a may become insufficient. As described above, in this embodiment, the oil accumulated in the housing 11 is forcibly conveyed to the oil pan 9 by the scavenging pump 40. This suppresses the oil from spouting from the oil separator 10R.

[0017] For example, it is possible to constantly suck oil from within the housing 11 using the scavenging pump 40 without providing the switching valve 30. In this case, however, the blow-by gas from within the oil separator 10R may be sucked by the scavenging pump 40, which may hinder the return of the blow-by gas to the intake system. Therefore, the ECU 50 opens the switching valve 30 at the following timing.

[0018] [Switching valve opening and closing control] FIG. 2 is a flow chart illustrating an example of the opening and closing control of the switching valve 30 executed by the ECU 50. This control is repeatedly executed while the ignition is on. The ECU 50 judges whether or not the operating point of the engine 1 is within the injection region (step S1). The operating point of the engine 1 is an operating state of the engine 1 determined based on the rotation speed and load of the engine 1. The injection region is an operating state in which, with the switching valve 30 closed, the flow rate of oil separated from the blow-by gas in the housing 11 is greater than the flow rate of oil discharged from the discharge port 12b. The injection region will be described later. If the answer is No in step S1, the ECU 50 maintains the switching valve 30 in a closed state (step S6).

[0019] If the answer is Yes in step S1, the ECU 50 determines whether a predetermined time α has elapsed while the operating point of the engine 1 is within the injection region (step S2). The predetermined time α is a variable value that changes according to the operating state of the engine 1 with the switching valve 30 closed.

[0020] FIG. 3 is an example of a map showing the jetting region. In FIG. 3, the vertical axis indicates the load of the engine 1, and the horizontal axis indicates the rotation speed of the engine 1. In the example of FIG. 3, the jetting region is divided into three regions according to the injection grace time. The jetting grace time is the time from when the operating point of the engine 1 belongs to the jetting region until oil is jetted from the inlet 12a. In the example of FIG. 3, the jetting grace time is set to A seconds, B seconds, and C seconds. The injection grace time is determined in advance based on experimental results. The predetermined time α is a value obtained by subtracting a predetermined T seconds from the injection grace time. T seconds is a time for ensuring a margin of time until oil is jetted from the inlet 12a. Therefore, T seconds is a time shorter than any of A seconds, B seconds, and C seconds. For example, when the operating point of the engine 1 belongs to a region where the injection grace time is set to A seconds, the predetermined time α is set to α=AT. When the operating point belongs to a region of B seconds, the predetermined time α is set to α=BT. If the operating point belongs to the region of C seconds, α is set to CT If the result of step S2 is No, the ECU 50 keeps the switching valve 30 closed (step S6).

[0021] If the answer is Yes in step S2, the ECU 50 opens the switching valve 30 (step S3). As a result, the oil accumulated in the housing 11 is forcibly transported to the oil pan 9 by the scavenging pump 40. This suppresses the oil from spouting out from the inlet 12a.

[0022] Next, the ECU 50 determines whether or not the operating point of the engine 1 falls outside the injection region (step S4). If the result in step S4 is No, step S4 is executed again.

[0023] If the answer is Yes in step S4, the ECU 50 judges whether a predetermined time β has elapsed since the operating point of the engine 1 went outside the ejection region (step S5). The predetermined time β is the time required for the oil to be sufficiently discharged from inside the housing 11 after the operating point of the engine 1 goes outside the ejection region. If the answer is No in step S5, step S4 is executed again. Note that if the operating point falls within the ejection region again after the answer is No in step S5, and then the answer is Yes in step S4, the time count since the operating point went outside the ejection region is reset to zero. If the answer is Yes in step S5, the ECU 50 closes the switching valve 30 (step S6).

[0024] In this manner, the switching valve 30 opens at a predetermined timing, thereby ensuring the return of blow-by gas to the intake system and suppressing the outflow of oil from the oil separator 10R.

[0025] A configuration similar to the oil separator 10R described above is also formed on the head cover 4L side. In this case, the scavenging pump 40 may be shared with the oil separator on the head cover 4L side. Also, such an oil separator may be provided on only one of the head covers 4L and 4R.

[0026] In addition, the oil separator is not limited to being formed in the cylinder head. For example, the oil separator may be formed in the cylinder block. In addition, the engine is not limited to being a V-type engine, and may be an in-line engine.

[0027] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0028] 1 Engine 10R Oil separator 24 Discharge pipe (piping) 30 Switching valve (opening / closing valve) 40 Scavenging pump (pump)

Claims

[Claim 1] The engine, an oil separator in which oil separated from blow-by gas generated in the engine and returned to an intake system is collected; A pump that sucks oil from the oil separator; a pipe connecting the oil separator and the pump; an on-off valve for opening and closing the piping; A control device for controlling the operation of the on-off valve, The control device opens the on-off valve when a predetermined time corresponding to an operating state of the engine has elapsed with the on-off valve closed.

Images