JP2014199037A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of efficient operation while easily avoiding knocking without using a knock sensor.SOLUTION: In an internal combustion engine including a control device 70 for controlling ignition timing, the control device 70 partitions an entire region specified by a relation between an engine rotational speed and a throttle opening when the internal combustion engine operates into a plurality of sections, and includes a storage unit 83 storing therein oil temperature/ignition timing correction tables corresponding to the respective sections. The control device 70 determines a section is what of the plurality of sections on the basis of detected values of the engine rotational speed and the throttle opening when the internal combustion engine operates, and determines ignition timing based on the oil temperature in the oil temperature/ignition timing correction table corresponding to the determined section.

Description

  The present invention relates to an internal combustion engine.

  Patent Literature 1 discloses an ignition timing control device for an internal combustion engine that determines ignition timing using a knock sensor. In an internal combustion engine, it is desired to increase the compression ratio while avoiding knocking, and there is a conventional engine that controls the ignition timing using a knock sensor as in Patent Document 1.

JP 2007-255212 A

  However, in the case of using a knock sensor like the ignition timing control device of Patent Document 1, the number of parts increases and the control becomes complicated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an internal combustion engine that can efficiently operate while avoiding knocking without using a knock sensor.

  As a means for solving the above problems, the invention according to claim 1 inputs an oil temperature sensor (72) for detecting an oil temperature inside the engine and detection values of various sensors including the oil temperature sensor (72). An internal combustion engine comprising a control device (70) for controlling the ignition timing according to the detected value, wherein the control device (70) is a relationship between the engine speed and the throttle opening when the internal combustion engine is operating. Is divided into a plurality of sections, and has a storage unit (83) for storing an oil temperature / ignition timing correction table corresponding to each section, and the engine speed and throttle opening when the internal combustion engine is operating. On the basis of the detected value of the plurality of sections, and based on the oil temperature in the oil temperature / ignition timing correction table corresponding to the determined section. Determining come ignition timing, characterized in that.

  According to a second aspect of the present invention, the engine speed is divided into at least a low speed area and a high speed area, and the throttle opening is divided into at least a low throttle area and a high throttle area. The entire region determined by the relationship with the opening is divided into a plurality of regions by at least the low rotation region, the high rotation region, the low throttle region, and the high throttle region, and the storage unit (83) includes the plurality of regions. Are stored in different oil temperature / ignition timing correction tables.

  According to a third aspect of the present invention, in the oil temperature / ignition timing correction table in the section divided by the low rotation region and the high throttle region, the ignition timing at the low oil temperature and the ignition timing at the high oil temperature are Is set to be larger than the oil temperature / ignition timing correction table in the other sections, and the ignition timing at the time of low oil temperature is set to the advance position. To do.

  According to a fourth aspect of the present invention, the plurality of sections include a plurality of sections including a low-rotation / high-throttle section corresponding to the sections partitioned by the low-rotation region and the high-throttle region, In the oil temperature / ignition timing correction table in the low rotation / high throttle section, the retard amount of the ignition timing of the high oil temperature is larger than that in the oil temperature / ignition timing correction table in the other section, and in the other section In the oil temperature / ignition timing correction table, the ignition timing of the high oil temperature in the low rotation / high throttle section becomes smaller as the throttle opening is smaller and the engine speed is higher than the low rotation / high throttle section. The retard amount of the ignition timing at the high oil temperature is set to be small with respect to the retard amount.

  The invention according to claim 5 includes a cylinder head (17) having an intake port (44) opened and closed by an intake valve (46) and an exhaust port (45) opened and closed by an exhaust valve (47), and the intake port. An inlet pipe (20) connected to (44), and a partition plate (60) formed in the inlet pipe (20) and partitioning at least the inlet pipe (20) into two passages (PL, PU); The flap valve is a flap valve having the vicinity of the upstream end of the partition plate (60) as a support shaft, and adjusts the amount of air in the two passages (PL, PU) partitioned by the partition plate (60). And the tumble control valve (65) closes one of the two passages (PL, PU) up to a predetermined throttle opening. By opening the other, a tumble flow is generated in the cylinder communicating with the intake port (44), and as the throttle opening increases from the predetermined throttle opening, of the two passages (PL, PU) One of the two is gradually opened to suppress the tumble flow to increase the intake air amount, and the plurality of compartments are partitioned by the throttle opening at which the tumble control valve (65) is opened from the closed time. There are compartments, and the storage unit (83) stores the different oil temperature / ignition timing correction tables corresponding to the compartments partitioned by the throttle opening when the tumble control valve (65) is opened from the closed time. It is characterized by that.

  According to the first and second aspects of the invention, the compression ratio is increased in the practical temperature range by giving the optimum ignition timing by the predetermined operating state section and the oil temperature of the internal combustion engine without using the knock sensor. While maintaining high thermal efficiency, knocking can be avoided when the oil temperature is high, and efficient operation is possible while simply avoiding knocking without using a knock sensor.

  In the invention according to claim 3, when the internal combustion engine is in an operating state partitioned by a low rotation region and a high throttle region, knocking is likely to occur at a high oil temperature and knocking avoidance conditions become severe, while the oil temperature is low. In this operating state, the ignition timing at low oil temperature should be advanced, and at high oil temperature, the retard amount should be increased to avoid knocking. Thus, high thermal efficiency can be ensured without causing knocking even when knocking avoidance conditions are severe.

  According to the fourth aspect of the present invention, high thermal efficiency can be secured without causing knocking by using an oil temperature / ignition timing correction table that matches the state of the internal combustion engine.

  In the fifth aspect of the invention, for example, fuel injection that closes the tumble control valve at low engine speed and makes the air-fuel ratio lean when tumble occurs, and makes the air-fuel ratio rich in the throttle opening range where the tumble control valve is opened. It is possible to perform control, but by having a separate oil temperature / ignition timing correction table in each partition divided by the throttle opening when the tumble control valve is open from the closed time, free setting while suppressing knocking And high thermal efficiency can be ensured.

1 is a diagram showing an internal combustion engine according to an embodiment of the present invention. It is a functional lineblock diagram of a control device which controls an internal-combustion engine concerning an embodiment of the present invention. It is a characteristic view of the relationship between the engine speed and the throttle opening when the internal combustion engine is operating according to the embodiment of the present invention. It is the figure which showed the oil temperature and ignition timing correction table memorize | stored in the memory | storage part of the said control apparatus. It is a flowchart explaining the ignition timing determination process by the said control apparatus. It is the figure which showed the graph explaining the opening / closing timing of the tumble control valve with which the internal combustion engine which concerns on embodiment of this invention is equipped.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the directions such as front, rear, left and right in the following description are the same as those in a vehicle equipped with the engine 10 of the present embodiment unless otherwise specified. An arrow FR indicating the forward direction and an arrow UP indicating the upward direction are shown at appropriate positions in the drawings used for the following description.

  An engine (internal combustion engine) 10 shown in FIG. 1 is an air-cooled four-stroke OHC two-valve single-cylinder engine and is used as a prime mover of a saddle-ride type vehicle such as a motorcycle. The engine 10 directs the rotation center axis (crank axis) C1 of the crankshaft 12 in the left-right direction (vehicle body width direction). The engine 10 raises the cylinder 13 above the front part of the crankcase 11. A crankshaft 12 is accommodated in the front portion of the crankcase 11, and a transmission 14 is accommodated in the rear portion of the crankcase 11.

  The main body parts such as the crankcase 11 and the cylinder 13 are made of an aluminum alloy, but an iron cylinder sleeve 15 is integrally cast into the cylinder 13 by casting or the like. An axis line (cylinder axis line) C2 along the rising direction of the cylinder 13 is inclined so that the upper part is positioned forward with respect to the vertical direction. In the figure, the arrow F1 indicates the rotation direction (forward rotation direction) of the crankshaft 12 during engine operation.

  The cylinder 13 includes a cylinder block 16 attached (or integrally formed) above the front portion of the crankcase 11, a cylinder head 17 attached above the cylinder block 16, and a head cover 18 attached above the cylinder head 17. Have In the cylinder block 16, the above-described cylinder sleeve 15 having a cylindrical shape along the cylinder axis C2 is provided. A piston 25 is fitted in the cylinder sleeve 15 so as to be able to reciprocate.

  A small end portion 27 of a connecting rod 26 is swingably attached to a piston pin 25a that penetrates the piston 25 in the left-right direction. The large end portion 28 of the connecting rod 26 is rotatably attached to the crankpin 12a of the crankshaft 12. Reference numeral 29 in the figure denotes a handle portion extending between the small end portion 27 and the large end portion 28 of the connecting rod 26.

  An intake port 44 is formed in the rear part of the cylinder head 17, and an exhaust port 45 is formed in the front part of the cylinder head 17. The intake valve port 42 that is the combustion chamber side opening of the intake port 44 is opened and closed by the intake valve 46, and the exhaust valve port 43 that is the combustion chamber side opening of the exhaust port 45 is opened and closed by the exhaust valve 47. An inlet pipe 20, which is an intake system component, is connected to the cylinder outside opening of the intake port 44, and an exhaust pipe (not shown), which is an exhaust system component, is connected to the cylinder outside opening of the exhaust port 45.

  The intake port 44 and the exhaust port 45 extend from the respective cylinder outer openings toward the cylinder center side, then curve downward toward the cylinder block 16 side, and reach the intake valve port 42 and the exhaust valve port 43. The intake valve port 42 and the exhaust valve port 43 are arranged in a distributed manner before and after a dome-shaped recess 51 formed in a lower end portion of the cylinder head 17 that faces the upper end portion of the cylinder block 16. The intake valve port 42 has a larger diameter than the exhaust valve port 43, and is arranged slightly offset forward from the distribution position with the cylinder axis C2 as the axis of symmetry. Along with this, the intake valve 46 and the exhaust valve 47 are also arranged slightly offset forward.

  In the cylinder head 17, a cam shaft 38 extending in the left and right directions in parallel with the crank shaft 12 is disposed. The cam shaft 38 has an intake cam that operates the intake valve 46 through the intake rocker arm 39a, and an exhaust cam that operates the exhaust valve 47 through the exhaust rocker arm 39b. The cam shaft 38 is linked and driven in synchronization with the crankshaft 12 via a cam chain, for example.

  The intake valve 46 and the exhaust valve 47 are opened by the intake cam and the exhaust cam of the cam shaft 38 via the intake rocker arm 39a and the exhaust rocker arm 39b, respectively. The intake valve 46 and the exhaust valve 47 are umbrella-shaped valve bodies 46a and 47a aligned with the intake valve opening 42 and the exhaust valve opening 43, respectively, and rod-like stems 46b and 47b extending from the valve bodies 46a and 47a to the head cover 18 side. And having. Both the stems 46b and 47b are arranged so as to be inclined with respect to the cylinder axis C2 so as to form a V shape that opens toward the head cover 18 in a side view. The cam shaft 38 is disposed between the stems 46b and 47b. The rocker arms 39a and 39b and the camshaft 38 are arranged slightly offset forward with respect to the cylinder axis C2, like the intake valve 46 and the exhaust valve 47.

Retainers 46c and 47c are attached to the tip portions (upper end portions) of the stems 46b and 47b, respectively. Valve springs 46d and 47d are respectively contracted between the retainers 46c and 47c and the seating surface of the cylinder head 17. The intake valve 46 and the exhaust valve 47 are urged toward the head cover 18 by the spring force of the valve springs 46d and 47d, and the intake valve port 42 and the exhaust valve port 43 are closed.
On the other hand, the operation of the camshaft 38 causes the intake valve 46 and the exhaust valve 47 to stroke toward the combustion chamber 40 against the urging force of the valve springs 46d and 47d, so that the intake valve 46 and the exhaust valve 47 are moved to the intake valve. The opening 42 and the exhaust valve opening 43 are opened. The stems 46b and 47b are held by the cylinder head 17 so as to be capable of stroke through cylindrical valve guides 46e and 47e, respectively.

  When the piston 25 descends when the intake valve 46 is opened, outside air is introduced into the intake port 44 through the inlet pipe 20, and fuel is injected from the injector 23, and these are mixed and introduced into the combustion chamber 40. The This air-fuel mixture is compressed as the piston 25 rises after the intake valve 46 is closed, and is ignited and burned by a spark plug (not shown). The exhaust gas after combustion is exhausted from the combustion chamber 40 through the exhaust port 45 by the ascending piston 25 when the exhaust valve 47 is opened, and is exhausted through an exhaust pipe (not shown).

  In this engine 10, the pressing force (sliding resistance) of the piston 25 against the inner wall of the cylinder at the maximum pressure in the combustion chamber 40 (at the beginning of the combustion stroke, when the piston 25 starts to descend from the top dead center) is reduced. As an object, an offset cylinder mechanism is employed in which the cylinder axis C2 is offset by a predetermined amount forward from the crank axis C1 (downstream in the forward rotation direction of the crank pin 12a when the piston 25 is at the top dead center).

  The inlet pipe 20 is connected to the intake port 44 of the cylinder head 17 via the connecting pipe 19, and the throttle body 21 is connected to the rear part of the inlet pipe 20. A throttle valve 22 and a tumble control valve 65 are provided in the throttle body 21. The inlet pipe 20 is provided with an injector 23.

  An air cleaner (not shown) is connected to the rear of the throttle body 21, and outside air that has passed through the air cleaner is introduced into the engine 10 through the throttle body 21 and the inlet pipe 20. Hereinafter, the intake upstream side and the intake downstream side may be simply referred to as the upstream side and the downstream side. Here, the throttle valve 22 is positioned upstream of the tumble control valve 65.

The combustion chamber 40 is formed between the top surface 25 b of the piston 25 in the cylinder sleeve 15 and the ceiling surface 41 facing the top surface 25 b of the piston 25 in the cylinder head 17.
The peripheral edge of the ceiling surface 41 is a circle that substantially matches the inner peripheral surface of the cylinder sleeve 15 when viewed from the direction of the cylinder axis C2. The ceiling surface 41 forms a long elliptical dome-shaped recess 51 in the front and rear of the air. An intake valve port 42 and an exhaust valve port 43 are opened on both sides in the long axis direction along the front-rear direction of the dome-shaped recess 51. On both the left and right sides of the dome-shaped recess 51, a pair of crescent-shaped left and right squishes (not shown) sandwiched between the periphery of the dome-shaped recess 51 and the periphery of the ceiling surface 41 are formed.

  On the left and right sides of the dome-shaped recess 51 between the intake valve port 42 and the exhaust valve port 43, a plug mounting hole for facing the electrode portion of the spark plug is formed. In the drawing, the ignition plug 100 facing the combustion chamber 40 side from the plug mounting hole is indicated by a two-dot chain line for convenience. In this embodiment, the intake air flow is controlled by opening and closing the tumble control valve 65 so that the air-fuel mixture is collected around the above-mentioned plug attachment hole, that is, around the tip of the spark plug 100. The flow (tumble flow) is optimized.

  A partition plate 60 that extends from the downstream side of the inlet pipe 20 to the downstream side (curved portion) of the intake port 44 is provided in the intake passage P that extends across the inlet pipe 20 and the intake port 44. The partition plate 60 partitions the intake passage P into an upper intake passage PU and a lower intake passage PL. The partition plate 60 includes an inlet pipe side partition plate 61 formed integrally with a resin forming portion on the downstream side of the inlet pipe 20 and an intake port side partition plate 62 formed integrally with the cylinder head 17 made of aluminum alloy.

  The downstream end of the inlet pipe side partition plate 61 protrudes downstream from the downstream opening end of the inlet pipe 20 and enters the intake port 44. The downstream end portion of the inlet pipe side partition plate 61 is pressed against the upstream end portion of the intake port side partition plate 62 with a pressing force due to elastic deformation. Thereby, the inlet pipe side partition plate 61 and the intake port side partition plate 62 are continuously connected.

  The partition plate 60 is disposed so as to be biased upward from a passage center line C3 extending in the vertical width center of the intake passage P having a circular cross section. Thereby, the passage sectional area of the upper intake passage PU becomes smaller than the passage sectional area of the lower intake passage PL. In the present embodiment, the ratio of the cross-sectional area of the upper intake passage PU and the cross-sectional area of the lower intake passage PL is approximately 3 to 7 from the upstream end to the downstream end of both passages.

  The intake port side partition plate 62 is bent along the longitudinal direction of the intake port 44. The downstream end of the intake port side partition plate 62 is cut out in a U-shape and opened downstream, and the lower end of the valve guide 46e of the intake valve 46 is aligned with the downstream end. As a result, the downstream end of the intake port side partition plate 62 extends as much as possible to a position where it overlaps the lower end of the valve guide 46e of the intake valve 46 in a side view, and the downstream end of the intake passage P (the intake valve port 42). The intake passage P is partitioned into an upper intake passage PU and a lower intake passage PL to the vicinity.

  The upper intake passage PU extends from the head cover 18 side to the cylinder inner peripheral side, and communicates with the central portion of the combustion chamber 40 through the cylinder inner peripheral side of the intake valve port 42. The lower intake passage PL extends from the cylinder block 16 side to the cylinder outer peripheral side, and communicates with the outer peripheral portion of the combustion chamber 40 through the cylinder outer peripheral side of the intake valve port 42. A fuel injection port of the injector 23 faces the upper intake passage PU, and fuel is injected into the intake air flowing through the upper intake passage PU.

  The throttle valve 22 is, for example, a butterfly valve in which a pair of semicircular plate valve bodies 22b are extended on both radial sides of a first rotating shaft 22a that extends in the left-right direction and is supported at both ends by the inlet pipe 20. . The throttle valve 22 is in a fully closed state in which the intake passage P is minimized by aligning or bringing the outer peripheral edges of the two-plate valve bodies 22b into or close to the inner peripheral surface of the intake passage in the throttle body 21.

  The throttle valve 22 is rotated fully in the clockwise direction from the fully closed state to open the intake passage P, and the both plate valve bodies 22b are parallel to the passage center line C3 to be fully opened. The throttle valve 22 is urged to close the intake passage P by an urging spring or the like, and opens the intake passage P by rotating against the urging force.

  In a portion of the inlet pipe 20 downstream of the throttle valve 22 and immediately below (in the vicinity of) the upstream end of the inlet pipe side partition plate 61, the intake chambers of the upper and lower intake passages PU and PL are adjusted to adjust the intake flow rate. An upper tumble control valve 65 for controlling the tumble flow is arranged. The tumble control valve 65 extends in parallel with the first rotation shaft 22a of the throttle valve 22 and has a single semicircular shape on one side in the radial direction of the second rotation shaft 65a supported by the inlet pipe 20 at both ends. This is a flap valve obtained by extending the plate valve body 65b. The tumble control valve 65 is interlocked with the throttle valve 22 via a link mechanism (not shown) and can be opened and closed together with the throttle valve 22. In the present embodiment, the tumble control valve 65 and the throttle valve 22 may be electrically controlled and interlocked.

  The tumble control valve 65 inclines the plate valve body 65b so as to be positioned on the lower side toward the upstream side with respect to the passage center line C3, and the outer peripheral edge of the plate valve body 65b is the inner peripheral surface of the intake passage in the throttle body 21. The linear base end edge of the plate valve body 65b is brought into contact with the lower surface of the upstream end portion of the inlet pipe side partition plate 61. Thereby, the tumble control valve 65 is in a fully closed state in which the upstream end of the lower intake passage PL is closed.

  The tumble control valve 65 is rotated in the clockwise direction from the fully closed state to open the upstream end of the lower intake passage PL and to be in the fully open state by making the plate valve body 65b substantially parallel to the passage center line C3. . The tumble control valve 65 is urged to close the lower intake passage PL by an urging spring or the like, and rotates against the urging force to open the lower intake passage PL. By the rotation of the tumble control valve 65, the ratio of the intake flow rate in the upper and lower intake passages PU, PL is changed.

  The engine 10 is in a low load state (low load mode) when the throttle opening (rotation angle from the fully closed state of the throttle valve 22) is small, and is in a high load state (high load mode) when the throttle opening is large. ). The tumble control valve 65 is mechanically controlled to rotate according to the throttle opening (that is, according to the load state of the engine 10) in the present embodiment.

The graph of FIG. 6 shows the change in the rotation angle (vertical axis) of the tumble control valve 65 with respect to the throttle opening (horizontal axis) when the fully closed state of the throttle valve 22 is 0 °.
The tumble control valve 65 does not open until the throttle opening reaches the predetermined angle θ1, only the upper intake passage PU is opened, and the tumble flow is caused to flow in the cylinder formed by the cylinder sleeve 15 communicating with the intake port 44. generate. Further, the tumble control valve 65 is opened as the throttle opening increases after the predetermined angle θ1, and gradually opens the lower intake passage PL to suppress the tumble flow and increase the intake air amount. The tumble control valve 65 is fully opened when the throttle valve 22 is fully opened.

  More specifically, when the engine 10 is in a low load operation state, if the throttle opening is a small opening less than the predetermined angle, the tumble control valve 65 is not opened and the intake inlet of the lower intake passage PL is closed. Leave. As a result, all of the intake air that flows around the throttle valve 22 flows into the relatively narrow upper intake passage PU and flows through the upper intake passage PU at a high speed. This intake air is guided to the vicinity of the intake valve port 42 by the partition plate 60 and is coupled with the restriction of the flow path on the cylinder outer periphery side of the intake valve port 42, so that most of the intake air flows from the cylinder inner periphery side of the intake valve port 42. It is introduced into the center of the combustion chamber 40. This intake air is accompanied by a high-speed flow directed to the exhaust valve port 43 side, thereby generating a strong tumble flow in the combustion chamber 40. At this time, the intake from the cylinder outer periphery side of the intake valve port 42 is suppressed, so that the occurrence of reverse tumble flow due to the intake is also suppressed. Thereby, the tumble flow in the combustion chamber 40 is strengthened and combustion at a low load is promoted.

  Further, when the engine 10 is in a medium load operation state, when the throttle opening becomes a medium opening exceeding the predetermined angle, the tumble control valve 65 opens and starts to open the lower intake passage PL. The amount of intake air flowing into the lower intake passage PL is increased according to the opening amount, and the intake air flow rate of the entire intake passage P is increased. At this time, the intake air flow rate in the upper intake passage PU is suppressed, and intake is also made through the lower intake passage PL, whereby the tumble flow in the combustion chamber 40 due to the intake air flowing through the upper intake passage PU is suppressed, and the lower intake air The tumble flow in the combustion chamber 40 is also suppressed by the reverse tumble flow caused by the intake air flowing through the passage PL.

  Further, when the engine 10 is in a high load operation state, when the throttle opening is maximized (fully opened), the tumble control valve 65 is also fully opened, and the amount of intake air introduced into the lower intake passage PL is maximized. Thereby, sufficient intake air flows through the upper and lower intake passages PU and PL, and the tumble flow in the combustion chamber 40 is further suppressed, and a sufficient intake amount is secured in the entire intake passage P.

  Thus, in the engine 10 of the present embodiment, the tumble control valve 65 is provided in the vicinity of the upstream end of the partition plate 60 that defines the intake passage P, and the tumble control valve 65 is opened and closed according to the throttle opening degree. By changing the proportion of the intake air (air amount) flowing through the upper and lower intake passages PU, PL, the strength of the tumble flow and the intake air flow rate can be adjusted according to the load state of the engine 10 to achieve good combustion. .

  In the figure, reference numeral 70 denotes a control unit (ECU) of the engine 10, and reference numeral 71 denotes a throttle opening sensor (Th sensor) that is attached to the throttle body 21 and detects the throttle opening of the throttle valve 22. ing. Reference numeral 72 denotes an oil temperature sensor (Tw sensor) that is attached to the crankcase 11 and detects the oil temperature inside the engine, and reference numeral 73 denotes an engine speed sensor (Tw sensor) that is attached to the crankcase 11 and detects the engine speed. Ne sensor).

  Referring to FIG. 2, ECU 70 inputs detection values of various sensors such as throttle opening sensor 71, oil temperature sensor 72, and engine speed sensor 73, and based on the detection values of the various sensors, fuel injection control unit 81. Thus, the fuel injection amount (fuel injection time) of the injector 23 is controlled, and the ignition timing of the spark plug 100 is controlled by the ignition control unit 82. The ignition control unit 82 has a basic ignition timing map and determines a reference ignition timing map value.

  Here, in this embodiment, the ECU 70 has a storage unit 83 in which an oil temperature / ignition timing correction table is stored, and corrects the reference ignition timing map value of the ignition control unit 82 based on the oil temperature / ignition timing correction table. Thus, the spark plug 100 is controlled.

  FIG. 3 shows a characteristic region determined by the relationship between the engine speed (Ne) and the throttle opening (Th) when the engine 10 is operating, and the characteristic region is divided into sections A to F. . In the present embodiment, the oil temperature / ignition timing correction table corresponding to each of the sections A to F is stored in the storage unit 83. Based on the detected value of the throttle opening (Th) from the throttle opening sensor 71 and the engine speed (Ne) from the engine speed sensor 73, the ECU 70 determines whether the current operating state is any of the sections A to F. The oil temperature / ignition timing correction table corresponding to the determined section is selected, and set in the ignition control unit 82 based on the selected oil temperature / ignition timing correction table and the detected value of the oil temperature sensor 72. Determine the ignition timing. The oil temperature / ignition timing correction table is a table in which the ignition timing is determined according to the oil temperature.

  In FIG. 3, a section A is divided into a low speed range (low Ne) defined by a predetermined engine speed range and a low throttle range up to θ1 (see also FIG. 6). It is. Hereinafter, the section A may be referred to as a low rotation / low throttle (low load operation state) section.

  The section B is a section that is partitioned by the low rotation region (low Ne) that has risen and the high throttle region that is defined by a predetermined throttle opening region in which the throttle opening is larger than θ1. Hereinafter, the section B may be referred to as a low rotation / high throttle (medium / high load operation state) section.

  The section C includes a medium speed range (medium Ne) defined by an engine speed range higher than the low speed range (low Ne) and a predetermined throttle opening that is evaluated as a low-load operation state in the medium speed range. It is a section partitioned by a medium rotation low throttle region defined by the region. Hereinafter, the section C may be referred to as a medium rotation / low throttle (low load operation state) section.

  The section D is a section defined by a medium rotation region (medium Ne) that has been aired and a medium rotation high throttle region that is defined by a predetermined throttle opening region that is larger than the upper limit value of the medium rotation low throttle region. is there. Hereinafter, the section D may be referred to as a medium rotation / high throttle (medium / high load operation state) section.

  The section E includes a high engine speed range (high Ne) defined by an engine speed region higher than the above-described medium engine speed region (medium Ne), and a predetermined throttle opening that is evaluated as a low load operation state in the high engine speed region. This section is divided into a high-rotation low-throttle area defined by the area. Hereinafter, the section E may be referred to as a high rotation / low throttle (low load operation state) section.

  The section F is a section that is partitioned by a high rotation area (high Ne) that has been aired and a high rotation high throttle area that is defined by a predetermined throttle opening range that is larger than the upper limit value of the high rotation low throttle area. is there. Hereinafter, the section F may be referred to as a high rotation / high throttle opening degree (medium / high load operation state) section.

  The oil temperature / ignition timing correction tables corresponding to the sections A to F are shown in FIGS. 4A to 4F in this order. In the oil temperature / ignition timing correction table in the figure, the horizontal axis corresponds to the oil temperature (TW), and the vertical axis corresponds to the ignition timing correction amount (IGTW). The vertical axis indicating the ignition timing correction amount has a retarded direction on the upper side.

In the oil temperature / ignition timing correction table corresponding to the sections A to F, the oil temperature is divided into 0 to TW1, low oil temperature areas divided into TW1 to TW2, medium and low oil temperature areas divided into TW2 to TW3, and TW2 to TW3. Is divided into a high oil temperature region divided by a medium oil temperature region, TW3 to TW4.
Further, in the oil temperature / ignition timing correction tables corresponding to the sections A to F, the ignition timing correction amounts θ _AA , θ _BA , θ _CA , θ _DA , θ set in the low oil temperature region partitioned by 0 to TW1. _EA and θ _FA are constant. Ignition timing correction amounts θ _AA , θ _BA , θ _CA , θ _DA , θ _EA , θ _FA set in the low oil temperature range are knocked according to the operating state (engine speed / throttle opening). It is determined in consideration of ease of occurrence and high compression ratio. Since it is difficult for knocking to occur when the oil temperature is low, the highest possible compression ratio is achieved as long as knocking does not occur. The ignition timing is set to a value that is different from each other.
In addition, the ignition timing correction amounts θ _AR , θ _BR , θ _CR , θ _DR , θ _ER , and θ _FR set in TW4 are also knocked according to the operating state (engine speed / throttle opening situation). It is determined taking into account the ease and realization of a high compression ratio, and knocking is likely to occur when the oil temperature is high, so it is greatly retarded compared to the ignition timing correction amount for the low oil temperature, It is set with a sufficient margin. Since the ease of knocking changes according to the operating state, the values of the ignition timing correction amounts θ _AR , θ _BR , θ _CR , θ _DR , θ _ER , and θ _FR are different from each other.

  In the oil temperature / ignition timing correction table of the present embodiment, predetermined ignition timing correction amounts are set in TW1, TW2, TW3, and TW4, and the ignition timing correction amounts located between these are determined by linear interpolation. Yes. It should be noted that the ignition timing correction amounts for TW2 and TW3 are set according to the operating state on the same basis as TW1 and TW4 between which these are sandwiched.

Here, in each operation state corresponding to the sections A to F, the ease of occurrence of knocking is different. In this example, the section B, which is the low rotation / high throttle (medium / high load operation state) section, is the most. Knocking is likely to occur, and the conditions for avoiding knocking are becoming stricter. For this reason, in the present embodiment, the ignition timing correction amount θ _BR set to TW4, which is a high oil temperature in the oil temperature / ignition timing correction table corresponding to the section B, is set to TW4 in the other oil temperature / ignition timing correction tables. The ignition timing correction amount is set to be retarded relative to the ignition timing correction amount set to. Furthermore, Δθ _B which is the amount of change on the retard side between the ignition timing correction amount θ _BA in the low oil temperature region 0 to TW1 and the ignition timing correction amount θ _{BR at} the time of high oil temperature is also changed to other oil temperature / ignition It is larger than that of the timing correction table (Δθ _A , Δθ _C , Δθ _D , Δθ _E , Δθ _F ).
Note that the ignition timing correction amount θ _BA in the oil temperature region 0 to TW1 in the oil temperature / ignition timing correction table corresponding to the section B is the ignition timing to be determined in the present embodiment. ) Is set to a value. This is because when the internal combustion engine is operating in a low rotation region and a high throttle region, knocking is likely to occur at high oil temperatures and knocking avoidance conditions become severe, while knocking does not occur when the oil temperature is low. This is because the thermal efficiency is increased as much as possible.

On the other hand, in another oil temperature / ignition timing correction table different from the section B, the higher the oil temperature in the second section, the smaller the throttle opening and the higher the engine speed relative to the second section. The retard amount of the ignition timing correction amount at the high oil temperature is set to be smaller than the retard amount (absolute value) of the ignition timing correction amount θ _BR .

Specifically, in the present embodiment, on the retard side, the relationship is θ _BR > θ _DR > θ _FR > θ _ER > θ _CR > θ _AR . This is because knocking is less likely to occur as the engine speed is higher, and knocking is less likely to occur as the throttle opening is smaller. In the present embodiment, by making the ignition timing correction table different in this way, the thermal efficiency is increased as much as possible while avoiding knocking.

  With reference to FIG. 5, the process of determining the oil temperature / ignition timing correction table by the ECU 70 will be described.

  In step S101, the ECU 70 determines whether or not the engine speed is in the low rotation region. If it is in the low rotation region, the ECU 70 proceeds to step S102. If not, the ECU 70 proceeds to step S103.

  Next, in step S102, the ECU 70 determines whether or not the throttle opening is in the low throttle region. If the throttle opening is in the low throttle region, the process proceeds to step S104. If not, the process proceeds to step S105.

  In step S104, the ECU 70 selects the low rotation and low throttle oil temperature / ignition timing correction table corresponding to the section A, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106. The ignition timing is determined by correcting the basic ignition timing map value, and the process returns to step S101. In step S105, the ECU 70 selects the low-rotation and high-throttle oil temperature / ignition timing correction table corresponding to the section B, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106. The ignition timing is determined, and the process returns to step S101.

  On the other hand, in step S103, the ECU 70 determines whether or not the engine speed is in the middle rotation region. If it is in the middle rotation region, the process proceeds to step S107. If not, the process proceeds to step S108.

  Next, in step S107, the ECU 70 determines whether or not the throttle opening is in the low throttle region. If the throttle opening is in the low throttle region, the process proceeds to step S109, and if not, the process proceeds to step S110.

  In step S109, the ECU 70 selects the medium rotation and low throttle oil temperature / ignition timing correction table corresponding to the section C, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106. The ignition timing is determined, and the process returns to step S101. In step S110, the ECU 70 selects the low-rotation and high-throttle oil temperature / ignition timing correction table corresponding to the section D, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106. The ignition timing is determined, and the process returns to step S101.

  In step S108, the ECU 70 determines whether or not the throttle opening is in the low throttle region. If the throttle opening is in the low throttle region, the process proceeds to step S111. If not, the process proceeds to step S112. .

In step S111, the ECU 70 selects a high rotation and low throttle oil temperature / ignition timing correction table corresponding to the section E, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106, The ignition timing is determined, and the process returns to step S101.
In step S112, the ECU 70 selects a high rotation and high throttle oil temperature / ignition timing correction table corresponding to the section F, and then, based on the oil temperature / ignition timing correction table and oil temperature selected in step S106. The ignition timing is determined, and the process returns to step S101.

  In the engine 10 of the present embodiment described above, the ECU 70 as the control device divides the entire region determined by the relationship between the engine speed and the throttle opening during operation of the internal combustion engine into a plurality of sections A to F. A storage unit 83 that stores an oil temperature / ignition timing correction table corresponding to each of the sections A to F is provided. Based on the detected values of the engine speed and the throttle opening when the internal combustion engine is operating, The ignition timing is determined based on the oil temperature in the oil temperature / ignition timing correction table corresponding to the determined section.

  In such an engine 10, without using a knock sensor, an optimal ignition timing is given by each predetermined operating state section and oil temperature of the internal combustion engine, so that a high compression efficiency is maintained and high thermal efficiency is maintained in a practical temperature range. However, knocking can be avoided when the oil temperature is high, and efficient operation is possible while simply avoiding knocking without using a knock sensor.

Further, in the present embodiment, the oil temperature / ignition timing correction table in the section B partitioned by the low rotation area and the high throttle area, the ignition timing correction amount θ _BA for the low oil temperature and the ignition timing for the high oil temperature. The amount of change on the retard side with respect to the correction amount θ _BR is set to be larger than the oil temperature / ignition timing correction table in other sections, and the ignition timing at the time of low oil temperature is set to the advance position. It is like that. Thus, in the present embodiment, high thermal efficiency can be ensured without causing knocking even in a severe knock avoidance condition.

Further, in the present embodiment, in the oil temperature / ignition timing correction table in the section B, the retard amount of the ignition timing correction amount θ _{BR for} the high oil temperature is larger than the oil temperature / ignition timing correction table in the other sections, In the oil temperature / ignition timing correction table in the other section, as the throttle opening is smaller and the engine speed is higher than section B, the ignition timing correction amount θ _{BR for} the higher oil temperature in section B is retarded. The retard amount of the ignition timing correction amount at the high oil temperature is set to be small with respect to the amount. Thereby, in this embodiment, it is possible to ensure high thermal efficiency without causing knocking by using an ignition timing correction table that matches the state of the internal combustion engine.

Further, in the present embodiment, the section A and the section B corresponding to the low rotation are in a low load state and a high state at θ1, which is a threshold value between the throttle opening when the tumble control valve 65 is closed and the throttle opening when the tumble control valve 65 is opened. Different oil temperature / ignition timing correction tables are set for each of the sections A and B.
In such a configuration, fuel injection control is performed to make the air-fuel ratio lean when the engine speed is low and the tumble control valve 65 is closed to generate a tumble, and to make the air-fuel ratio rich in the throttle opening range where the tumble control valve 65 is opened. However, by having a separate oil temperature / ignition timing correction table for each, it is possible to set freely while suppressing knocking, and to ensure high thermal efficiency.

The present invention is not limited to the above-described embodiment. For example, the engine of various valve mechanisms such as a DOHC type, a multi-cylinder engine such as a parallel or V type, and a vertically mounted crankshaft along the vehicle longitudinal direction. The present invention may be applied to various types of reciprocating engines such as engines.
The configuration in the above embodiment is an example of the present invention, and various modifications can be made without departing from the gist of the present invention, such as replacing the component of the embodiment with a known component.

  Further, for example, in the present embodiment, the entire region determined by the relationship between the engine speed and the throttle opening during operation of the internal combustion engine is partitioned into six partitions A to F. It may be less or more than this.

DESCRIPTION OF SYMBOLS 70 Control apparatus 72 Oil temperature sensor 83 Memory | storage part A-F Section 17 Cylinder head 20 Inlet pipe 44 Intake port 45 Exhaust port 46 Intake valve 47 Exhaust valve 60 Partition plate 65 Tumble control valve PL Lower intake passage PU Upper intake passage

Claims (5)

An oil temperature sensor (72) for detecting the oil temperature inside the engine;
In an internal combustion engine comprising: a control device (70) that inputs detection values of various sensors including the oil temperature sensor (72) and controls ignition timing in accordance with the detection values;
The control device (70)
A storage unit (83) for storing an oil temperature / ignition timing correction table corresponding to each of the plurality of sections divided into an entire area determined by the relationship between the engine speed and the throttle opening during operation of the internal combustion engine. Have
The oil temperature / ignition timing correction table corresponding to the determined section is determined based on the detected values of the engine speed and the throttle opening when the internal combustion engine is operating, and which of the plurality of sections is determined. And determining the ignition timing based on the oil temperature. The engine speed is divided into at least a low rotation region and a high rotation region, and the throttle opening is divided into at least a low throttle region and a high throttle region,
The entire region determined by the relationship between the engine speed and the throttle opening during operation of the internal combustion engine is divided into a plurality of regions by at least the low rotation region, the high rotation region, the low throttle region, and the high throttle region,
The internal combustion engine according to claim 1, wherein the storage unit (83) stores different oil temperature / ignition timing correction tables corresponding to the plurality of sections.   In the oil temperature / ignition timing correction table in the section divided by the low rotation area and the high throttle area, the amount of change on the retard side between the ignition timing at the low oil temperature and the ignition timing at the high oil temperature is The internal combustion engine according to claim 2, wherein the internal combustion engine is set to be larger than the oil temperature / ignition timing table in other sections, and the ignition timing at low oil temperature is set to an advance position. The plurality of sections include a plurality of sections including a low-rotation / high-throttle section corresponding to the section partitioned by the low-rotation region and the high throttle region,
In the oil temperature / ignition timing correction table in the low rotation / high throttle section, the retard amount of the ignition timing of the high oil temperature is larger than the oil temperature / ignition timing correction table in the other sections,
In the oil temperature / ignition timing correction table in the other section, the lower the throttle opening and the higher the engine speed, the higher the engine speed in the low / high throttle section. 4. The internal combustion engine according to claim 3, wherein the retard amount of the ignition timing of the oil temperature is set to be smaller than the retard amount of the ignition timing of the oil temperature. A cylinder head (17) having an intake port (44) opened and closed by an intake valve (46) and an exhaust port (45) opened and closed by an exhaust valve (47);
An inlet pipe (20) connected to the intake port (44);
A partition plate (60) formed in the inlet pipe (20) and partitioning at least the inlet pipe (20) into two passages (PL, PU);
A flap valve having a shaft near the upstream end portion of the partition plate (60) as a support shaft, and a tumble control valve that adjusts the air amount in the two passages (PL, PU) partitioned by the partition plate (60) (65)
The tumble control valve (65) closes one of the two passages (PL, PU) up to a predetermined throttle opening and opens the other to open a cylinder connected to the intake port (44). As the throttle opening increases from the predetermined throttle opening, one of the two passages (PL, PU) is gradually opened to suppress the tumble flow and increase the intake air amount. It is what
In the plurality of sections, there is a section partitioned by a throttle opening at which the tumble control valve (65) is opened from the closed time,
The storage unit (83) stores different oil temperature / ignition timing correction tables corresponding to sections partitioned by a throttle opening when the tumble control valve (65) is opened from the closed time. The internal combustion engine according to any one of claims 1 to 4.

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