engine

Abstract

To provide an engine having high rotation detection accuracy of a crankshaft 1.SOLUTION: An engine comprises axial flow-type engine cooling fans 7 and 10 that blows backward engine cooling air 7d, 7e and 10d to a front side of the engine. In view from the front side of the engine cooling fans 7 and 10, a part or the whole of an exposed part 4b of a crankshaft sensor 4 exposed on the outside of a rotor storage case 6 is arranged in an overlapping manner in projection regions 7c and 10c of the engine cooling fans 7 and 10 that are positioned on the inside of rotation loci 7b and 10c of outer peripheral edges 7a and 10a of the engine cooling fans 7 and 10. Preferably, a part or the whole of a connector 4c is arranged in an overlapping manner in the projection regions 7c and 10c of the engine cooling fans 7 and 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an engine, and more particularly to an engine with high accuracy in detecting the rotation of a crankshaft. [Background technology]

[0002] Conventionally, there has been an engine equipped with a rotation detection device, which includes a crankshaft rotor rotated by the crankshaft and a crankshaft sensor facing the crankshaft rotor, and is configured to detect the rotation state of the crankshaft based on detection of the rotation phase of the crankshaft rotor by the crankshaft sensor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-236510 A (see Figures 1, 2, and 5) Summary of the Invention [Problem to be solved by the invention]

[0004] <Problem> The accuracy of detecting the rotation state of the crankshaft may be reduced. In the engine of Patent Document 1, when viewed from the front of the engine cooling fan, the crankshaft sensor is located outside the projection area of ​​the engine cooling fan, which is located inside the rotation trajectory of the outer edge of the engine cooling fan.As a result, the crankshaft sensor is not air-cooled, and the crankshaft sensor may overheat due to heat generated by the engine, which may reduce the accuracy of detecting the rotation state of the crankshaft.

[0005] An object of the present invention is to provide an engine that can detect the rotation of a crankshaft with high accuracy. [Means for solving the problem]

[0006] The main features of the present invention are as follows. As shown in FIG. 2(A), the engine is provided with axial flow engine cooling fans (7)(10) that blow engine cooling air (7d), (7e), (10d) backward toward the front side of the engine, and as shown in FIG. 1, the engine is arranged so that a part or all of an exposed portion (4b) of a crankshaft sensor (4) exposed outside a rotor housing case (6) overlaps with a projected area (7c), (10c) of the engine cooling fan (7), (10) that is located inside a rotation locus (7b), (10b) of an outer peripheral edge (7a), (10a) of the engine cooling fan (7), (10) when viewed from the front side of the engine cooling fan (7), (10). [Effects of the Invention]

[0007] The present invention has the following advantages. <Effect> The rotation state of the crankshaft (2) can be detected with high accuracy. As illustrated in FIGS. 1, 2(A) and 2(C), in this engine, the exposed portion 4b of the crankshaft sensor 4 is air-cooled by the rearward-flowing engine cooling air 7d, 7e and 10d, which prevents the crankshaft sensor 4 from overheating due to heat generated by the engine, thereby improving the accuracy of detecting the rotation state of the crankshaft 2. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a front view of a main part of an engine according to an embodiment of the present invention. [Figure 2] 2(A) is a cross-sectional view taken along line AA in FIG. 1, FIG. 2(B) is a cross-sectional view taken along line BB in FIG. 2(A), and FIG. 2(C) is a cross-sectional view taken along line CC in FIG. 2(A). [Figure 3] 1 is a front view showing the arrangement of a gear train and a rotation detection device of an engine according to an embodiment of the present invention. [Figure 4] 1 is a front view of an engine according to an embodiment of the present invention. FIG. [Figure 5] FIG. 5 is a left side view of the engine of FIG. 4. [Figure 6] FIG. 5 is a plan view of the engine of FIG. 4. [Figure 7] FIG. 5 is a right side view of the engine of FIG. 4. [Figure 8] FIG. 5 is a rear view of the engine of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1 to 8 are diagrams illustrating an engine according to an embodiment of the present invention, and in this embodiment, a vertical, four-cycle in-line multi-cylinder (four-cylinder) spark ignition engine will be described.

[0010] This engine is a dual-fuel engine, and as shown in Figure 5, includes a cylinder block (5), a cylinder head (14) attached to the top of the cylinder block (5), a cylinder head cover (17) attached to the top of the cylinder head (14), a gear case (18) attached to the front of the cylinder block (5), and an oil pan (19) attached to the bottom of the cylinder block (5). The cylinder block (5) includes a cylinder section (5b) in its upper half and a crankcase (5a) in its lower half. The crankcase (5a) houses the crankshaft (2). The engine includes an intake system, a fuel supply system, an ignition system, and an exhaust system.

[0011] As shown in FIG. 5, the direction in which the crankshaft (2) is installed is the front-rear direction, one side of the front-rear direction is the front, and as shown in FIGS. 4 and 6, the width direction of the engine perpendicular to the front-rear direction is the lateral direction. As shown in FIG. 6, the intake system includes an intake manifold (20) disposed on one side (right side) of the cylinder head, and an electronic throttle (21) attached to the front of the intake manifold (20). The throttle opening of the electronic throttle (21) is controlled by an electronic control device (22) shown in FIG. 7. The electronic control unit 22 is an engine ECU 22a. EUC is an abbreviation for electronic control unit. As shown in FIG. 7, the intake manifold (20) includes a rectangular parallelepiped collector (20a) that is long in the front-rear direction, and four branch pipes (20b) branching from the collector (20a), and an electronic throttle (21) is attached to the front of the collector (20a). An intake valve (not shown) that opens and closes a valve opening of an intake port (not shown) in the cylinder head (14) is driven to open and close by a cam (not shown) on a valve camshaft (23) shown in FIG.

[0012] As shown in Figures 6 and 7, the fuel supply device includes a gas mixer (24) mounted in front of the electronic throttle (21), and as shown in Figures 4 and 8, a fuel injector (26) attached in a branched manner to the delivery pipe (25), so that the supply of gas fuel to the gas mixer (24) or the supply of liquid fuel to the delivery pipe (25) can be selected. The gas fuel supplied to the gas mixer (24) is mixed with air to form an air-fuel mixture, which is then supplied to the intake manifold (20). The liquid fuel supplied to the delivery pipe (25) is supplied to each cylinder from the fuel injector (26) via the intake port of each cylinder, where it forms an air-fuel mixture in each cylinder. The amount of gas fuel supplied to the gas mixer (24) and the amount of fuel injected from the fuel injector (26) are controlled by the engine ECU (22a). The fuel gas may be LNG (liquefied natural gas), LPG (liquefied petroleum gas), or the like. The liquid fuel may be gasoline or the like.

[0013] As shown in FIGS. 6 and 8, the ignition device includes a coil-on plug (27), and the air-fuel mixture in each cylinder is ignited by a spark generated by the coil-on plug (27). The ignition timing of the coil-on plug (27) is controlled by the engine ECU (22a) based on the engine speed and the engine load. The ignition timing of the coil-on plug (27) is set based on the crank angle. The engine rotation speed and crank angle are calculated by the engine ECU (22a) based on the detection of the rotation state of the crankshaft (2) by the rotation detection device (1).

[0014] As shown in Figures 5 and 6, the exhaust system includes an exhaust manifold (15) arranged on the other lateral side (left side) of the cylinder head (14), opposite to the intake manifold (20) on one lateral side thereof, and a heat insulating cover (16) that covers the exhaust manifold (15). An exhaust valve (not shown) that opens and closes a valve opening of an exhaust port (not shown) in the cylinder head (14) is driven to open and close by a cam (not shown) on a valve camshaft (23) shown in FIG.

[0015] As shown in FIG. 1, the engine is equipped with a rotation detection device (1). As shown in Figures 2(A) and 2(C), the rotation detection device (1) includes a crankshaft rotor (3) rotated by a crankshaft (2) and a crankshaft sensor (4) facing the crankshaft rotor (3), and is configured to detect the rotation state of the crankshaft (2) based on the detection of the rotation phase of the crankshaft rotor (3) by the crankshaft sensor (4). As shown in FIG. 2(A), a rotor housing case (6) for housing the crankshaft rotor (3) is disposed at the front side of the engine, and the sensor body (4a) of the crankshaft sensor (4) is inserted into the rotor housing case (6). As shown in FIG. 2(A), the engine is provided with axial flow engine cooling fans (7)(10) that blow engine cooling air (7d), (7e), (10d) backward to the front side of the engine. As shown in FIG. 1, when viewed from the front side of the engine cooling fans (7), (10), the exposed portion (4b) of the crankshaft sensor (4) exposed outside the rotor housing case (6) is arranged so that part or all of the exposed portion (4b) overlaps with the projected areas (7c), (10c) of the engine cooling fans (7), (10) that are located inside the rotation trajectories (7b), (10b) of the outer peripheral edges (7a), (10a) of the engine cooling fans (7), (10).

[0016] As shown in FIGS. 1, 2(A) and 2(C), in this engine, the exposed portion 4b of the crankshaft sensor 4 is air-cooled by the rearward-flowing engine cooling air 7d, 7e and 10d, which prevents the crankshaft sensor 4 from overheating due to heat generated by the engine, thereby improving the accuracy of detecting the rotation state of the crankshaft 2.

[0017] As shown in Figures 1, 2(A), 3, and 4, the engine cooling fans (7) and (10) include a high-position engine cooling fan (7) and a low-position engine cooling fan (10), and either one is selected and used depending on the engine specifications. As shown in Fig. 1, when a high-position engine cooling fan (7) is selected, it is positioned so that a part of the exposed portion (4b) of the crankshaft sensor (4) overlaps with the projected area (7c) of its rotation trajectory (7b). As shown in Fig. 2(A), in this case, the exposed portion (4b) of the crankshaft sensor (4) is air-cooled by the engine cooling airflow (7d) directed directly rearward and the engine cooling airflow (7e) directed diagonally rearward. The engine cooling airflow (7e) flowing diagonally downward and backward is generated by twisting of the blades of the engine cooling fan (7) located at a high position. As shown in Figure 1, when a low-positioned engine cooling fan (10) is selected, the exposed portion (4b) of the crankshaft sensor (4) is positioned so that it entirely overlaps with the projected area (10c) of its rotation trajectory (10b). As shown in Figure 2(A), in this case, the exposed portion (4b) of the crankshaft sensor (4) is air-cooled by the engine cooling fan (10d) facing directly rearward. 5 to 7, only the engine cooling fan (7) at a high position is shown, and the engine cooling fan (10) at a low position is not shown.

[0018] As shown in FIG. 2(C), the crankshaft rotor (3) of the rotation detection device (1) has a number of teeth (3b) arranged circumferentially on its peripheral edge (3a), and the crankshaft sensor (4) is composed of an electromagnetic pickup that detects the passage of the teeth (3b). By counting the rotation pulses, the rotation speed and rotation phase of the crankshaft rotor (3) are calculated by the engine ECU (22a).

[0019] 3, this engine is equipped with a cylinder discrimination device (28), which includes a camshaft rotor (not shown) rotated by the valve camshaft (23) and a camshaft sensor (28) facing the camshaft rotor, and discriminates the stroke of the combustion cycle of each cylinder based on the detection of the rotational phase of the camshaft rotor by the camshaft sensor (28). That is, the engine ECU (22a) discriminates whether a predetermined cylinder whose piston is moving toward bottom dead center is on an intake stroke or an expansion stroke, and whether a predetermined cylinder whose piston is moving toward top dead center is on a compression stroke or an exhaust stroke. Whether the engine cooling fans (7) and (10) are in the high position or the low position, the camshaft sensor (28) is arranged so that the entire camshaft sensor (28) overlaps with the projected areas (7c) and (10c) of the rotation loci (7b) and (10b), and therefore the camshaft sensor (28) is air-cooled by the engine cooling air (7d) and (10d) directed directly backward.

[0020] As shown in Fig. 3, the valve camshaft (23) is driven by the crankshaft (2) via a gear train (18a) housed in the gear case (18). The gear train (18a) includes a crank gear (not shown) attached to the crankshaft (2), an idle gear (29), and a valve cam gear (23a) attached to the valve camshaft (23). The idle gear (29) is disposed between the crank gear and the valve cam gear (23a), and the valve camshaft (23) rotates once while the crankshaft (2) rotates twice.

[0021] As shown in FIGS. 2A to 2C, the exposed portion 4b of the crankshaft sensor 4 includes a connector 4c for connecting the cable 8 to the sensor body 4a, and is arranged so that part or all of the connector 4c overlaps with the projected areas 7c and 10c of the engine cooling fans 7 and 10, as shown in FIG. 1.

[0022] As shown in Figures 1, 2(A) and 2(C), in this engine, the connector (4c) is air-cooled by the rearward-flowing engine cooling air (7d), (7e), and (10d), and overheating of the connector (4c) is suppressed, so that the rotation state of the crankshaft (2) can be detected with high accuracy.

[0023] As shown in FIG. 1, in the case of a high-positioned engine cooling fan (7), the connector (4c) is arranged so that a part of the connector (4c) overlaps with the projected area (7c) of the engine cooling fan (7), and as shown in FIG. 2(A), the connector (4c) is air-cooled by the engine cooling air (7d) directed directly rearward and the engine cooling air (7e) directed diagonally rearward. As shown in FIG. 1, in the case of a low-positioned engine cooling fan (10), the connector (4c) is positioned so that the entire connector (4c) overlaps the projected area (10c) of the engine cooling fan (10), and as shown in FIG. 2(A), the connector (4c) is air-cooled by the engine cooling air (10d) directed directly rearward.

[0024] As shown in Figures 2(A) to (C), the rotor housing case (6) has a sensor insertion boss (6b) protruding from its peripheral wall (6a), and the sensor insertion boss (6b) has a flange seat (6c) on its protruding end face. The exposed portion (4b) of the crankshaft sensor (4) has a flange (4d) adjacent to the connector (4c). As shown in Figures 1, 2(A) and 2(C), the sensor body (4a) of the crankshaft sensor (4) is inserted into the sensor insertion boss (6b), and the flange (4d) of the crankshaft sensor (4) is received in the flange receiving seat (6c).

[0025] As shown in Figures 1, 2(A) and 2(C), in this engine, the rearward-flowing engine cooling airflow (7e) (10d) also blows against the boundary peripheral portion (6d) between the flange seat (6c) adjacent to the connector (4c) and the flange (4d), and dust that tends to accumulate at this boundary peripheral portion (6d) is blown away. Therefore, even if the crankshaft sensor (4) is inserted or removed during maintenance or replacement of the crankshaft sensor (4), the sensor body (4a) of the crankshaft sensor (4) is unlikely to be contaminated with dust.

[0026] As shown in Figures 1, 2(A) and 2(C), when the engine cooling fan (7) is positioned high, the engine cooling air (7e) blows obliquely downward and rearward onto the boundary peripheral portion (6d), and when the engine cooling fan (10) is positioned low, the engine cooling air (10d) blows directly rearward onto the boundary peripheral portion (6d).

[0027] As shown in FIG. 2(A), the connector (4c) is inclined so that its front surface (4ca) gradually approaches the boundary peripheral portion (6d) between the flange seat (6c) and the flange (4d) as it moves rearward. As shown in FIG. 2(A), in this engine, the engine cooling air (7f) (10f) deflected along the slope of the front surface (4ca) of the connector (4c) is guided to the boundary peripheral portion (6d) between the flange seat (6c) and the flange (4d), where dust is removed, thereby providing a high contamination prevention function for the crankshaft sensor (4).

[0028] As shown in Figures 1, 2(A) and 2(C), in the case of a high-positioned engine cooling fan (7), the engine cooling air (7d) directed directly backward is deflected to become engine cooling air (7f) and guided to the boundary peripheral portion (6d), and in the case of a low-positioned engine cooling fan (10), the engine cooling air (10d) directed directly backward is deflected to become engine cooling air (10f) and guided to the boundary peripheral portion (6d).

[0029] As shown in FIG. 2(A), the sensor body (4a) of the crankshaft sensor (4) inserted into the sensor insertion boss (6b) is inclined so as to gradually move away from the engine front side as it moves away from the crankshaft rotor (3). As shown in FIG. 2(A), in this engine, during maintenance or when replacing the crankshaft sensor (4), the crankshaft sensor (4) can be inserted into the sensor insertion boss (6b) from a front separation position (11) that is away from the front of the engine, or can be removed toward the front separation position (11). This makes it difficult for the crankshaft sensor (4) to interfere with parts on the front side of the engine above it (such as the cooling water introduction passage (30) of the water pump), making it easy to insert and remove the crankshaft sensor (4).

[0030] As shown in FIG. 4, when viewed from the front side of the engine, the cable (8) led out from the connector (4c) is introduced into a head exhaust side gap (14b) between the belt tensioner (13) of the fan belt (12) of the engine cooling fans (7) (10) and the exhaust side wall (14a) of the cylinder head (14), and from this head exhaust side gap (14b), as shown in FIG. 6, the cable is led out to the intake side of the engine via the front side of the exhaust manifold (15) and above the engine. As shown in FIG. 6, in this engine, the cable (8) does not come into contact with the exhaust manifold (15) or an exhaust duct (not shown) connected to the exhaust manifold (15), and the cable (8) is less likely to be damaged by heat.

[0031] As shown in FIG. 4, the width direction of the engine, which is perpendicular to the front-rear direction, is defined as the horizontal direction, and the cable (8) led out along the central axis (4cb) of the connector (4c) is inclined upward toward the head exhaust side gap (14b) on one side of the engine in the horizontal direction. As shown in FIGS. 1 and 4, in this engine, bending stress is not easily applied to the connection portion between the connector (4c) and the cable (8), and the connection portion between the connector (4c) and the cable (8) is not easily damaged. [Explanation of symbols]

[0032] (1)...Rotation detection device, (2)...Crankshaft, (3)...Crankshaft rotor, (4)...Crankshaft sensor, (4a)...Sensor body, (4b)...Exposed portion, (4c)...Connector, (4ca)...Front surface, (4cb)...Central axis, (4d)...Flange, (6)...Rotor housing case, (6a)...Peripheral wall, (6b)...Sensor insertion boss, (6c)...Flange seat, (6d)...Boundary periphery, (7)...High-position engine cooling fan, (7a)...Outer periphery, (7b)...Rotation trajectory , (7c)...Projected area, (7d)(7e)...Rearward-directed engine cooling air, (8)...Cable, (9)...Engine cooling air, (10)...Low-positioned engine cooling fan, (10a)...Outer edge, (10b)...Rotation path, (10c)...Projected area, (10d)...Rearward-directed engine cooling air, (12)...Fan belt, (13)...Belt tensioner, (14)...Cylinder head, (14a)...Exhaust side wall, (14b)...Head exhaust side gap, (15)...Exhaust manifold.

Claims

1. A rotation detection device (1) is provided, The rotation detection device (1) includes a crankshaft rotor (3) rotated by a crankshaft (2) and a crankshaft sensor (4) facing the crankshaft rotor (3), and is configured to detect the rotation state of the crankshaft (2) based on detection of the rotation phase of the crankshaft rotor (3) by the crankshaft sensor (4); The crankshaft (2) is installed in the front-rear direction, with one side facing forward. A rotor housing case (6) for housing a crankshaft rotor (3) is disposed at the front of the engine, and a sensor body (4a) of the crankshaft sensor (4) is inserted into the rotor housing case (6). An engine characterized by comprising an axial flow type engine cooling fan (7)(10) that blows engine cooling air (7d)(7f)(10d) backward to the front side of the engine, and wherein, when viewed from the front side of the engine cooling fan (7)(10), a projection area (7c)(10c) of the engine cooling fan (7)(10) that is located inside the rotation locus (7b)(10b) of the outer peripheral edge (7a)(10a) of the engine cooling fan (7)(10) is arranged so that a part or all of an exposed portion (4b) of a crankshaft sensor (4) exposed outside a rotor housing case (6) overlaps.

2. 2. The engine according to claim 1, An engine characterized in that the exposed portion (4b) of the crankshaft sensor (4) is provided with a connector (4c) that connects a cable (8) to the sensor body (4a), and the connector (4c) is arranged so that part or all of it overlaps with the projected areas (7c) and (10c) of the engine cooling fans (7) and (10).

3. 3. The engine according to claim 2, The rotor housing case (6) has a sensor insertion boss (6b) protruding from its peripheral wall (6a), and the sensor insertion boss (6b) has a flange seat (6c) on its protruding end surface; The exposed portion (4b) of the crankshaft sensor (4) has a flange (4d) adjacent to the connector (4c), An engine characterized in that a sensor body (4a) of a crankshaft sensor (4) is inserted into a sensor insertion boss (6b), and a flange (4d) of the crankshaft sensor (4) is received in a flange receiving seat (6c).

4. 4. The engine according to claim 3, The connector (4c) is inclined so that its front surface (4ca) gradually approaches the boundary peripheral portion (6d) of the flange seat (6c) and the flange (4d) as it moves rearward.

5. 5. The engine according to claim 4, The engine is characterized in that the sensor body (4a) of the crankshaft sensor (4) inserted into the sensor insertion boss (6b) is inclined so as to gradually move away from the front side of the engine as it moves away from the crankshaft rotor (3).

6. In the engine according to any one of claims 2 to 5, When viewed from the front side of the engine, a cable (8) led out from the connector (4c) is introduced into a head exhaust side gap (14b) between a belt tensioner (13) of a fan belt (12) of engine cooling fans (7) (10) and an exhaust side wall (14a) of a cylinder head (14), and is led out from this head exhaust side gap (14b) to the front side of an exhaust manifold (15) and above the engine to the intake side of the engine.

7. 7. The engine according to claim 6, The engine is characterized in that the width direction of the engine, which is perpendicular to the front-to-rear direction, is the horizontal direction, and the cable (8) led out along the central axis (4cb) of the connector (4c) is inclined upward toward the head exhaust side gap (14b) on one side of the engine in the horizontal direction.

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