Coil cooling system and internal combustion engine system
The coil cooling device integrates a heat sink with the intake path member to cool ignition coils using intake air, addressing overheating issues in lean-burn engines by adjusting fuel injection and ignition timing, ensuring efficient operation and cost-effectiveness.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- DAIHATSU MOTOR CO LTD
- Filing Date
- 2024-11-14
- Publication Date
- 2026-05-26
AI Technical Summary
Existing ignition coils in internal combustion engines face challenges in effective cooling, particularly in lean-burn engines with direct injection systems where the ignition coils are prone to overheating due to increased energy demand and high-pressure fuel injection, leading to higher manufacturing costs and ignition difficulties.
A coil cooling device is designed with a heat sink integrated into the intake path member, where the case housing the ignition coil is attached to face or be in contact with the intake path, utilizing intake air for cooling, and a control device adjusts fuel injection and ignition timing based on current flow to manage heat generation.
The solution effectively cools the ignition coil by leveraging intake air, maintains optimal air-fuel ratio, and prevents overheating, thereby enhancing engine performance and reducing manufacturing costs.
Smart Images
Figure 2026086298000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a coil cooling device and an internal combustion engine system.
Background Art
[0002] As an invention related to a conventional coil cooling device, for example, an ignition coil for an internal combustion engine described in Patent Document 1 is known. This ignition coil for an internal combustion engine includes a heat sink.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] As described above, there is a desire to effectively cool the ignition coil.
[0005] Therefore, an object of the present invention is to provide a coil cooling device and an internal combustion engine system that can cool an ignition coil.
Means for Solving the Problems
[0006] The coil cooling device according to the first aspect includes an intake passage member that forms an intake passage for supplying air to an internal combustion engine, an ignition coil electrically connected to a spark plug, a case that houses the ignition coil, and the coil cooling device has a structure of (A) or (B), (A) The case includes a heat sink, and the case is attached to the intake path member such that the heat sink faces the intake path through an opening provided in the intake path member. (B) The intake path member includes a heat sink facing the intake path, and the case is attached to the outer surface of the intake path member so as to be in contact with the heat sink. This is a coil cooling device.
[0007] The coil cooling device on the second side is An intake path member that forms an intake path for supplying air to an internal combustion engine, The ignition coil, which is electrically connected to the spark plug, A case for housing the ignition coil, It is equipped with, The intake path member has a cylindrical section that extends along the intake path, The coil cooling device has the structure of (A) or (B), (A) The case is attached to the intake path member in the cylindrical section such that a portion of the case faces the intake path through an opening provided in the intake path member. (B) The intake path member is attached to the outer surface of the intake path member in the cylindrical section. This is a coil cooling device.
[0008] The third aspect is, The heat sink has a plurality of plate-shaped fins, The normals of the main surfaces of the plurality of fins are perpendicular to the intake direction in the intake path. This is the coil cooling device described on the first side.
[0009] The fourth aspect is, A coil cooling device as described in any of the first to third sides, Internal combustion engines and An injector for injecting fuel into the internal combustion engine, Control device and comprises, When the value of the current flowing through the ignition coil per unit time increases, the control device reduces the fuel injected by the injector or delays the timing of the ignition plug's discharge. It is an internal combustion engine system.
Advantages of the Invention
[0010] According to the present invention, the ignition coil can be cooled.
Brief Description of the Drawings
[0011] [Figure 1] FIG. 1 is a block diagram of the internal combustion engine system 1. [Figure 2] FIG. 2 is a perspective view of the ignition coil 26 and the case 27. [Figure 3] FIG. 3 is a cross-sectional view of the intake passage R11 parallel to the intake direction D1. [Figure 4] FIG. 4 is a cross-sectional view of the intake passage R11 perpendicular to the intake direction D1. [Figure 5] FIG. 5 is a flowchart executed by the control device 100. [Figure 6] FIG. 6 is a cross-sectional view of the intake passage R11 perpendicular to the intake direction D1. [Figure 7] FIG. 7 is a cross-sectional view of the intake passage R11 parallel to the intake direction D1.
Modes for Carrying Out the Invention
[0012] (Embodiment) [Structure of the Internal Combustion Engine System 1] Hereinafter, the structure of the internal combustion engine system 1 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the internal combustion engine system 1. FIG. 2 is a perspective view of the ignition coil 26 and the case 27. FIG. 3 is a cross-sectional view of the intake passage R11 parallel to the intake direction D1. FIG. 4 is a cross-sectional view of the intake passage R11 perpendicular to the intake direction D1.
[0013] The internal combustion engine system 1 is the power source for a vehicle. The vehicle is, for example, a four-wheeled automobile. The internal combustion engine system 1 comprises an internal combustion engine 10, an exhaust path member 28, an injector 29, a throttle valve 32, a coil cooling device 50, and a control device 100.
[0014] The internal combustion engine 10 is a four-stroke engine that uses gasoline as fuel. Although Figure 2 shows one cylinder, the internal combustion engine 10 has three cylinders. However, since the structure of the three cylinders is the same, we will focus on one cylinder for explanation. The internal combustion engine 10 comprises an engine body 12, a crankshaft 14, a connecting rod 16, a piston 18, an intake valve 20, an exhaust valve 22, and an ignition device 23.
[0015] The engine body 12 includes a cylinder block 12a, a cylinder head 12b, and a crankcase 12c. The cylinder block 12a is provided with a cylinder Sy. The cylinder Sy has a cylindrical shape with a central axis extending along the vertical axis.
[0016] The cylinder head 12b is located on top of the cylinder block 12a. The cylinder head 12b is fixed to the cylinder block 12a. The cylinder head 12b is provided with a combustion chamber Sp. The combustion chamber Sp is located on top of the cylinder Sy. The combustion chamber Sp is connected to the cylinder Sy.
[0017] The cylinder head 12b is provided with an intake port P1 and an exhaust port P2. The intake port P1 and exhaust port P2 are connected to the combustion chamber Sp. The intake port P1 is part of the intake path R11. The intake path R11 is a pipe through which air or a mixture of fuel and air passes. The throttle valve 32 is located in the intake path R11. The throttle valve 32 adjusts the amount of air (intake volume) supplied to the internal combustion engine 10 under the control of the control device 100 (described later).
[0018] The injector 29 is located in the intake passage R11. The injector 29 injects fuel into the internal combustion engine 10. In this embodiment, the injector 29 injects atomized fuel into the intake passage R11. In other words, the internal combustion engine 10 employs a port injection system. This forms a fuel-air mixture.
[0019] The exhaust port P2 is part of the exhaust path R12. The exhaust path R12 is a pipe through which exhaust gases pass. The exhaust path member 28 is a cylindrical member that forms the exhaust path R12. Thus, the internal combustion engine 10 is provided with a combustion chamber Sp, an intake path R11 connected to the combustion chamber Sp, and an exhaust path R12.
[0020] The crankcase 12c is located below the cylinder block 12a. The crankcase 12c is fixed to the cylinder block 12a. The engine body 12 described above is made of cast iron.
[0021] The crankshaft 14 is supported by the cylinder block 12a and the crankcase 12c. The crankshaft 14 can rotate about a rotation axis perpendicular to the vertical axis.
[0022] The piston 18 is located within the cylinder Sy. The piston 18 has a cylindrical shape. The piston 18 can move upward and downward.
[0023] The connecting rod 16 connects the crankshaft 14 and the piston 18. As a result, when the crankshaft 14 rotates, the piston 18 moves up and down. The combustion chamber Sp mentioned above is the space enclosed by the piston 18 and the cylinder head 12b when the piston 18 is at top dead center (TDC).
[0024] The intake valve 20 is supported by the cylinder head 12b. The intake valve 20 is located downstream of the injector 29 in the intake path R11. The intake valve 20 opens and closes the intake path R11. When the intake valve 20 opens the intake path R11, a mixture of fuel and air flows from the intake path R11 into the combustion chamber Sp. The exhaust valve 22 is supported by the cylinder head 12b. The exhaust valve 22 opens and closes the exhaust path R12. When the exhaust valve 22 opens the exhaust path R12, exhaust gas flows out from Sp into the exhaust path R12. The intake valve 20 and exhaust valve 22 described above are driven by a valve train mechanism (not shown).
[0025] The ignition system 23 burns the fuel injected by the injector 29. The ignition system 23 includes a spark plug 24 and an ignition coil 26. The spark plug 24 is fixed to the cylinder head 12b. The spark plug 24 includes a center electrode and a ground electrode. The center electrode and the ground electrode are exposed to the combustion chamber Sp.
[0026] The ignition coil 26 is electrically connected to the spark plug 24. Based on an ignition signal from a control device (not shown), the ignition coil 26 applies a high voltage between the center electrode and the ground electrode of the spark plug 24. This generates a spark between the center electrode and the ground electrode of the spark plug 24, igniting the fuel in the combustion chamber Sp.
[0027] The coil cooling device 50 cools the ignition coil 26. The coil cooling device 50 comprises an intake path member 33, an ignition coil 26, and a case 27.
[0028] The intake path member 33 forms an intake path R11 for supplying air to the internal combustion engine 10. The intake path member 33 includes an air cleaner box 34, a cylindrical member 36, a surge tank 38, and a cylindrical member 40. The air cleaner box 34, cylindrical member 36, surge tank 38, and cylindrical member 40 are arranged in this order from upstream to downstream in the intake path R11.
[0029] The air cleaner box 34 has a box shape. The air cleaner box 34 houses a filter. The filter removes foreign matter from the air taken in from outside the vehicle. The air that has passed through the filter passes through the cylindrical member 36 and flows into the surge tank 38.
[0030] The surge tank 38 has a box shape. The surge tank 38 functions to stabilize the intake pressure of the internal combustion engine 10. The air that passes through the surge tank 38 flows into the internal combustion engine 10 through the cylindrical member 40.
[0031] Here, the intake path member 33 has cylindrical sections A1 and A2 that have a cylindrical shape extending along the intake direction D1, which is the direction in which intake air flows. Cylindrical member 36 corresponds to cylindrical section A1. Cylindrical member 40 corresponds to cylindrical section A2. Furthermore, the area of the cross-section of cylindrical members 36 and 40 perpendicular to the intake direction D1 is smaller than the area of the cross-section of the air cleaner box 34 and surge tank 38 perpendicular to the intake direction D1.
[0032] As shown in Figure 2, the case 27 houses the ignition coil 26. More specifically, the case 27 includes a case body 27a and a heat sink 27b. The case body 27a is a rectangular box. The ignition coil 26 is housed in the case body 27a. The heat sink 27b is provided on the upper surface of the case body 27a. The heat sink 27b has a plurality of plate-shaped fins 27c. Each of the plurality of fins 27c has two main surfaces. The plurality of fins 27c are arranged at equal intervals such that the normal directions of the plurality of fins 27c coincide. The heat sink 27b described above is made of, for example, metal.
[0033] As shown in Figure 3, the case 27 is attached to the intake path member 33 in the cylindrical section A1 such that a portion of the case 27 faces the intake path R11 through an opening Op provided in the intake path member 33. More specifically, as shown in Figure 4, the cylindrical member 36 is provided with an opening Op. The upper surface of the case body 27a and the heat sink 27b cover the opening Op. However, a sealing material 60 is provided between the upper surface of the case body 27a and the cylindrical member 36 so that no gap is formed between the upper surface of the case body 27a and the cylindrical member 36. Thus, the case 27 is attached to the intake path member 33 such that the heat sink 27b faces the intake path R11 through an opening Op provided in the intake path member 33.
[0034] Furthermore, as shown in Figure 3, the multiple fins 27c extend along the intake direction D1. As a result, the normal D2 of the main surface of the multiple fins 27c is perpendicular to the intake direction D1 in the intake path R11.
[0035] The control device 100 controls the operation of the internal combustion engine 10. In this embodiment, the control device 100 controls the amount of fuel injected by the injector 29 and the timing of the discharge of the spark plug 24. The control device 100 is, for example, an ECU (Engine Control Unit) and includes a circuit board and electronic components.
[0036] [Operation of Internal Combustion Engine System 1] Next, the operation of the internal combustion engine system 1 will be explained with reference to the diagrams. Figure 5 is a flowchart of the actions performed by the control device 100.
[0037] First, the control device 100 acquires the rotational speed x of the internal combustion engine 10 (step S1). The internal combustion engine 10 is equipped with a crank angle sensor (not shown). Based on the crank angle signal output from the crank angle sensor, the control device 100 calculates the rotational speed x (revolutions per unit time) of the internal combustion engine 10.
[0038] Next, the control device 100 obtains the current value y flowing through the ignition coil 26 (step S2). The ignition coil 26 is equipped with a current sensor (not shown). Based on the current value signal output from the current sensor, the control device 100 determines the current value y flowing through the ignition coil 26.
[0039] Next, the control device 100 determines the injection amount z based on the rotational speed x acquired in step S1 and the current value y acquired in step S2 (step S6). At this time, the following relationship holds between the rotational speed x, the current value y, and the injection amount z. • As the rotational speed x increases, the amount of fuel injected per unit time z increases. • As the rotational speed x increases, the energizing time decreases. (This decreases when viewed in terms of the current value y.)
[0040] Therefore, as the rotational speed x increases, the injection amount z decreases. As the current value y increases, the injection amount z decreases. Also, the current value α flowing through the ignition coil 26 per unit time is the product of the rotational speed x and the current value y. For this reason, in steps S1 to S3, the control device 100 controls the amount of fuel injected by the injector 29 when the current value α flowing through the ignition coil 26 per unit time increases.
[0041] Next, the control device 100 determines whether or not to terminate this process (step S4). If the process is not terminated, the process returns to step S1.
[0042] [effect] The coil cooling device 50 can cool the ignition coil 26. More specifically, in recent years, development of lean-burn engines has progressed. Direct injection is often used in lean-burn engines.
[0043] However, the adoption of direct injection necessitates injectors and delivery pipes capable of injecting fuel at high pressure. As a result, the manufacturing cost of lean-burn engines increases.
[0044] Therefore, the inventors of this invention considered adopting a port injection system for a lean-burn engine. However, in a lean-burn engine, the amount of fuel injected by the injector 29 is small. As a result, the fuel-air mixture is difficult to ignite. Therefore, the ignition coil 26 needs to be supplied with more energy by the spark plug 24. However, the ignition coil 26 is prone to overheating.
[0045] In the coil cooling device 50, the case 27 is attached to the intake path member 33 such that the heat sink 27b faces the intake path R11 through an opening Op provided in the intake path member 33. The heat sink 27b has a large surface area. Therefore, the heat sink 27b is cooled by the intake air. Thus, the ignition coil 26 is cooled by the heat sink 27b.
[0046] Furthermore, the ignition coil 26 tends to overheat when the rotational speed of the internal combustion engine 10 increases. When the rotational speed of the internal combustion engine 10 increases, the intake air volume increases. Therefore, the ignition coil 26 is cooled by the intake air. In this way, the coil cooling device 50 exhibits a high cooling effect when the ignition coil 26 is prone to overheating, and a low cooling effect when the ignition coil 26 is not prone to overheating.
[0047] Furthermore, in the coil cooling device 50, the case 27 is attached to the intake path member 33 in the cylindrical section A1 such that a portion of the case 27 faces the intake path R11 through an opening Op provided in the intake path member 33. In the cylindrical section A1, the intake airflow velocity is high. Therefore, the case 27 is effectively cooled by the intake air. Thus, the ignition coil 26 is effectively cooled by the case 27.
[0048] In the coil cooling device 50, the normals of the main surfaces of the multiple fins 27c are perpendicular to the intake direction D1 in the intake path R11. As a result, the multiple fins 27c do not obstruct the intake air flowing through the intake path R11.
[0049] The current value α flowing through the ignition coil 26 per unit time is correlated with the amount of heat generated by the ignition coil 26. Specifically, as the current value α increases, the amount of heat generated by the ignition coil 26 increases. Therefore, in steps S1 to S3, the control device 100 reduces the amount of fuel injected by the injector 29 when the current value α flowing through the ignition coil 26 per unit time increases. As a result, when the amount of heat generated by the ignition coil 26 increases, the amount of fuel injected by the injector 29 decreases. Consequently, even if the intake air temperature rises, the A / F ratio does not decrease easily due to the increased heat generated by the ignition coil 26.
[0050] (First variation) The coil cooling device 50a according to the first modified example will be described below with reference to the drawings. Figure 6 is a cross-sectional view of the intake path R11 perpendicular to the intake direction D1.
[0051] The coil cooling device 50a differs from the coil cooling device 50 in that the heat sink 27b is provided on the intake path member 33. More specifically, the intake path member 33 includes the heat sink 27b facing the intake path R11. The case 27 includes a heat transfer section 27d. The heat transfer section 27d is provided on the upper surface of the case body 27a. The heat transfer section 27d is made of the same material as the heat sink 27b, for example, metal. The heat transfer section 27d of the case 27 is attached to the outer circumferential surface of the intake path member 33 in the cylindrical section A1. In this modified example, the case 27 is attached to the outer circumferential surface of the intake path member 33 so as to be in contact with the heat sink 27b. The other structures of the coil cooling device 50a are the same as those of the coil cooling device 50, so their description is omitted. The coil cooling device 50a can achieve the same effects as the coil cooling device 50.
[0052] (Third variation) The coil cooling device 50b according to the third modified example will be described below with reference to the drawings. Figure 7 is a cross-sectional view of the intake path R11 parallel to the intake direction D1.
[0053] The coil cooling device 50b differs from the coil cooling device 50 in the shape of its multiple fins 27c. More specifically, the multiple fins 27c of the coil cooling device 50b have a rod shape that extends vertically. The multiple fins 27c are arranged in a checkerboard pattern. More specifically, nine fins 27c are arranged in a row at equal intervals in a direction D3 perpendicular to the intake direction D1. Multiple rows containing nine fins 27c are arranged at equal intervals in the intake direction D1. However, two adjacent rows containing nine fins 27c are offset by half a pitch in the direction D3 perpendicular to the intake direction D1. Half a pitch is half the length of the space between the fins 27c and the fins 27c themselves. The other structures of the coil cooling device 50b are the same as those of the coil cooling device 50, so their description is omitted. The coil cooling device 50b can achieve the same effect as the coil cooling device 50.
[0054] (Other embodiments) The coil cooling device according to the present invention is not limited to coil cooling devices 50, 50a, and 50b, but can be modified within the scope of its gist. Furthermore, the configurations of coil cooling devices 50, 50a, and 50b may be combined in any way.
[0055] Furthermore, in steps S1 to S3, if the current value α flowing through the ignition coil 26 per unit time increases, the control device 100 may retard the timing of the discharge of the spark plug 24. This reduces the pressure in the combustion chamber Sp at the time of ignition by the spark plug 24. As a result, knocking is suppressed.
[0056] The shape of the multiple fins 27c of the coil cooling devices 50 and 50a may be the same as the shape of the multiple fins 27c of the coil cooling device 50b.
[0057] Furthermore, the number of cylinders in the internal combustion engine 10 is not limited to 3. The number of cylinders in the internal combustion engine 10 may be 1 or 2 or more. [Explanation of Symbols]
[0058] 1: Internal combustion engine system 10: Internal combustion engine 23:Ignition device 24: Spark plug 26: Ignition coil 27: Case 27a: Case body 27b: Heatsink 27c: Finn 27d: Heat transfer section 28: Exhaust path component 29: Injector 32: Throttle valve 33: Intake path component 34: Air cleaner box 36,40: Cylindrical member 38: Surge Tank 50, 50a, 50b: Coil cooling device 60: Sealant 100: Control device A1, A2: Cylindrical section D1: Intake direction Op: Opening R11: Intake path R12: Exhaust path
Claims
1. The coil cooling device is An intake path member that forms an intake path for supplying air to an internal combustion engine, The ignition coil, which is electrically connected to the spark plug, A case for housing the ignition coil, It is equipped with, The coil cooling device has the structure of (A) or (B), (A) The case includes a heat sink, and the case is attached to the intake path member such that the heat sink faces the intake path through an opening provided in the intake path member. (B) The intake path member includes a heat sink facing the intake path, and the case is attached to the outer surface of the intake path member so as to be in contact with the heat sink. Coil cooling device.
2. The coil cooling device is An intake path member that forms an intake path for supplying air to an internal combustion engine, The ignition coil, which is electrically connected to the spark plug, A case for housing the ignition coil, It is equipped with, The intake path member has a cylindrical section that extends along the intake path, The coil cooling device has the structure of (A) or (B), (A) The case is attached to the intake path member in the cylindrical section such that a portion of the case faces the intake path through an opening provided in the intake path member. (B) The intake path member is attached to the outer surface of the intake path member in the cylindrical section. Coil cooling device.
3. The heat sink has a plurality of plate-shaped fins, The normals of the main surfaces of the plurality of fins are perpendicular to the intake direction in the intake path. The coil cooling device according to claim 1.