Multi-cylinder engine
Patent Information
- Application Number
- PCT/JP2026/009624
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-17
- Filing Date
- 2026-03-12
- Publication Date
- 2026-10-22
Smart Images
Figure JP2026009624_22102026_PF_FP_ABST
Abstract
Description
Multi-cylinder engine
[0001] The present invention relates to a multi-cylinder engine, and more particularly, to a multi-cylinder engine capable of improving the robustness and corrosion resistance of an intake pressure sensor.
[0002] Conventionally, there is a multi-cylinder engine including an intake distribution unit that distributes intake air to a plurality of cylinders, an EGR device that recirculates part of exhaust gas as recirculated exhaust gas into the intake air in the intake distribution unit, an intake pressure sensor that detects the intake pressure of the intake air containing the recirculated exhaust gas within the intake distribution unit, an intake pressure guide passage that communicates the intake distribution unit with the intake pressure sensor, and an electronic control unit that controls the engine using parameters including a detected value of the intake pressure detected by the intake pressure sensor (see, for example, Patent Document 1).
[0003] Japanese Unexamined Patent Publication No. 2022-176712 (see Figures 1, 3, 4)
[0004] In the multi-cylinder engine of Patent Document 1, the material of the peripheral wall of the intake pressure guide passage is not specified, but a rubber tube is generally used. This case has the following problems. <<Problem 1>> The robustness of the intake pressure sensor may be reduced. When the entire peripheral wall of the intake pressure guide passage is a rubber tube, the entire peripheral wall vibrates due to engine cooling air and engine vibration, and this vibration acts as a disturbance, making the detected value of the intake pressure by the intake pressure sensor prone to fluctuation, which may reduce the robustness of the intake pressure sensor. <<Problem 2>> The intake pressure sensor may be corroded. When the entire peripheral wall of the intake pressure guide passage is a rubber tube, the heat dissipation performance of the peripheral wall is low, water vapor in the intake air inside the intake distribution unit passes through the intake pressure guide passage, and condensed water of strong acid in which nitrogen oxides and sulfur oxides in the recirculated exhaust gas contained in the intake air are dissolved is generated near the intake pressure sensor, which may corrode the intake pressure sensor.
[0005] An object of the present invention is to provide a multi-cylinder engine capable of improving the robustness and corrosion resistance of an intake pressure sensor.
[0006] The main features of the present invention are as follows: The intake pressure guide passage comprises a starting end passage portion and a terminal end passage portion, and the peripheral wall of the starting end passage portion and the peripheral wall of the intake distribution means are integrally formed from a continuous, identical metal material, characterized in that the multi-cylinder engine.
[0007] The present invention provides the following effects: <Effect 1-1> Increased robustness of the intake pressure sensor In this engine, even when subjected to engine cooling air or engine vibration, the peripheral wall of the starting end portion of the intake pressure guide passage is less prone to vibration, thus suppressing fluctuations in the intake pressure detected by the intake pressure sensor and increasing the robustness of the intake pressure sensor. <Effect 1-2> Increased corrosion resistance of the intake pressure sensor In this engine, the peripheral wall of the starting end portion of the intake pressure guide passage has high heat dissipation properties, so water vapor in the intake air within the intake air distribution means condenses in the starting end portion of the passage, making it difficult for condensed water of strong acid to be generated near the intake pressure sensor, thus increasing the corrosion resistance of the intake pressure sensor.
[0008] This is a vertical cross-sectional perspective view of the vicinity of the intake distribution means of a vertical in-line four-cylinder diesel engine according to an embodiment of the present invention. This diagram illustrates the intake distribution means used in the engine of Figure 1, with Figure 2(A) being a plan view and Figure 2(B) being a cross-sectional view taken along line B-B in Figure 2(A). This diagram illustrates the intake distribution means of Figure 2, with Figure 3(A) being a cross-sectional view taken along line IIIA-IIIA in Figure 2(B), Figure 3(B) being a cross-sectional view taken along line IIIB-IIIB in Figure 2(B), Figure 3(C) being a cross-sectional view taken along line IIIC-IIIC in Figure 2(B), Figure 3(D) being a cross-sectional view taken along line IIID-IIID in Figure 2(B), and Figure 3(E) being a cross-sectional view taken along line IIIE-IIIE in Figure 2(B). This is a schematic diagram showing the intake and exhaust paths of the engine of Figure 1 and the wiring of the electronic control device and various sensors used to control the engine.
[0009] This is a plan view of the area near the intake distribution means in Figure 1. This is a view taken in the direction of arrow VI in Figure 5. Figure 7(A) is a cross-sectional view taken along line VIIA-VIIA in Figure 6, and Figure 7(B) is a cross-sectional view taken along line VIIB-VIIB in Figure 6. This is a plan view of the engine in Figure 1. This is a right side view of the engine in Figure 8. This is a front view of the engine in Figure 8. This is a left side view of the engine in Figure 8. This is a rear view of the engine in Figure 8.
[0010] Figures 1 to 12 illustrate a multi-cylinder engine according to an embodiment of the present invention, in which a vertical in-line multi-cylinder diesel engine is described.
[0011] In this engine, as shown in Figures 9 and 11, the mounting direction of the crankshaft 13 is the front-rear direction, as shown in Figures 10 and 12, the width direction of the engine perpendicular to the front-rear direction is the left-right lateral direction, and as shown in Figures 9 to 12, the direction perpendicular to the front-rear direction and the left-right lateral direction is the up-down direction. As shown in Figures 9 and 11, in the front-rear direction, the engine cooling fan 16 side is the front and the opposite side is the rear, as shown in Figures 10 and 12, in the left-right direction, the left side is the left hand side and the right hand side is the right hand side for an observer facing forward at the engine's position, and as shown in Figures 9 to 11, in the up-down direction, the cylinder head cover 14 side is the upper side and the opposite side is the lower side. As shown in Figure 9, this engine comprises a cylinder block 20, a cylinder head 15 mounted on top of the cylinder block 20, a cylinder head cover 14 mounted on top of the cylinder head 15, an engine cooling fan 16 located on the front side of the cylinder block 20, a flywheel housing 21 located on the rear side of the cylinder block 20, and an oil pan 22 mounted on the bottom of the cylinder block 20. An exhaust treatment case 23 is located above the flywheel housing 21.
[0012] As shown in Figure 4, the cylinder block 20 has four cylinders 1, 2, 3, and 4 arranged in the front-to-back direction. As shown in Figures 9 to 12, the cylinder block 20 houses the crankshaft 13 in its lower half. This engine is equipped with an intake system, a fuel supply system, an exhaust system, an EGR system, and an exhaust treatment system.
[0013] As shown in Figure 9, the intake system includes an intake distribution means 6 mounted on the right side of the cylinder head 15 and an intake throttle 24 mounted above the intake distribution means 6. The intake distribution means 6 is a so-called intake manifold, but as shown in Figure 2(A), it has a box-shaped structure without branch pipes, so the term intake distribution means is used. As shown in Figure 4, intake air 5 is supercharged in the intake distribution means 6 from the compressor 25a of the supercharger 25 through the supercharger pipe 26, intake throttle 24, intake / exhaust confluence passage 6f, and intake inlet 6e. As shown in Figure 4, an intake pressure sensor 9a, a differential pressure sensor 9b, and an intake air temperature sensor 19 are electrically connected to the intake throttle 24 via an electronic control unit 12. The electronic control unit 12 calculates the intake air volume using the detected differential pressure value 9ba, the detected intake pressure value 6aa, the detected intake air temperature value 6d, and the exhaust volume as parameters 11, and controls the opening degree of the intake throttle 24 based on the calculated intake air volume. The electronic control unit 12 uses an engine ECU. ECU is an abbreviation for electronic control unit.
[0014] As shown in Figure 4, the fuel supply system is equipped with fuel injectors 1b, 2b, 3b, and 4b for each cylinder 1, 2, 3, and 4 connected to the common rail 27. In this engine, an accelerator sensor 28 and an engine speed sensor 29 are electrically connected to the fuel injectors 1b, 2b, 3b, and 4b via an electronic control unit 12. The electronic control unit 12 calculates the fuel injection start time and fuel injection amount using the detected accelerator opening value 28a and the detected engine speed value 29a as parameters, and controls the fuel injection start time and fuel injection duration of the fuel injectors 1b, 2b, 3b, and 4b, so that a predetermined amount of fuel is injected from the fuel injectors 1b, 2b, 3b, and 4b to each cylinder 1, 2, 3, and 4 at a predetermined timing.
[0015] As shown in Figure 4, the exhaust system includes an exhaust manifold 30 mounted on one side of the cylinder head 15 and a supercharger 25 mounted on the exhaust manifold 30. The EGR device 8 is equipped with an EGR valve 8e and recirculates a portion of the exhaust 7 from the exhaust manifold 30 as recirculated exhaust 7a to the intake 5 in the intake distribution means 6, thereby lowering the maximum combustion temperature in each cylinder 1, 2, 3, and 4 and reducing NOx in the exhaust 7. In this engine, the electronic control device 12 controls the opening degree of the EGR valve 8e using the detected engine speed value 29a and fuel injection amount as parameters.
[0016] As shown in Figure 4, an intake-exhaust confluence passage 6f is located between the intake throttle 24 and the intake port 6e, where the recirculated exhaust 7a is combined with the intake 5. Between the exhaust manifold 30 and the intake-exhaust confluence passage 6f, the following are arranged in order from the upstream side of the recirculated exhaust 7a flow path: cooler upstream chamber 8b, EGR cooler 8c, valve upstream passage portion 8d, EGR valve 8e, valve downstream chamber 8f, and valve downstream passage portion 8g.
[0017] As shown in Figure 3(C), the peripheral wall 8fa of the valve downstream chamber 8f rises upward from the upper surface 6bb of the peripheral wall 6b of the intake distribution means 6, and is equipped with a valve mounting flange 8fb at its upper end. As shown in Figure 3(D), the peripheral wall 8ga of the valve downstream passage portion 8g also rises upward from the upper surface 6bb of the peripheral wall 6b of the intake distribution means 6. As shown in Figure 3(E), the peripheral wall 6fa of the intake and exhaust confluence passage 6f also rises upward from the upper surface 6bb of the peripheral wall 6b of the intake distribution means 6, and is equipped with a throttle mounting flange 8gb at its upper end. As shown in Figure 1, the EGR valve 8e is mounted on the valve mounting flange 8fb, and the intake throttle 24 is mounted on the throttle mounting flange 8gb. The EGR cooler 8c and the valve upstream passage portion 8d are arranged between the cooler upstream chamber 8b and the EGR valve 8e. The peripheral wall 8fa of the valve downstream chamber 8f, the peripheral wall 8ga of the valve downstream passage portion 8g, the peripheral wall 6fa of the intake and exhaust confluence passage 6f, and the peripheral wall 6b of the intake distribution means 6 are all integrally formed from the same continuous metal material. These peripheral walls 8fa, 8ga, 6fa, and 6b are made of aluminum or an aluminum alloy and are integrally formed by aluminum die casting.
[0018] As shown in Figure 9, the exhaust treatment device includes an exhaust treatment case 23, which houses a DOC (not shown) on the upstream side of the exhaust and a DPF (not shown) on the downstream side of the exhaust. DPF is an abbreviation for diesel particulate filter, which captures PM in the exhaust. PM is an abbreviation for particulate matter. DOC is an abbreviation for diesel oxidation catalyst, which oxidizes CO (carbon monoxide) and NO (nitric oxide) in the exhaust. As shown in Figure 11, the upstream side of the exhaust treatment case 23 is connected to the exhaust outlet of the exhaust turbine 25b of the turbocharger 25 by an exhaust relay pipe 31. In this exhaust treatment device, the exhaust is passed through the DOC and DPF in that order, capturing PM in the exhaust 7 with the DPF, and NO (nitric oxide) in the exhaust is oxidized with the DOC to obtain NO ２ Nitrogen dioxide is used to continuously oxidize and burn PM accumulated in the DPF at a relatively low temperature. When the amount of PM accumulated in the DPF reaches a predetermined regeneration requirement, the electronic control device 12 shown in Figure 4 controls the exhaust temperature by after-injection or post-injection from fuel injectors 1b, 2b, 3b, and 4b, thereby incinerating and removing the PM accumulated in the DPF.
[0019] As shown in Figure 4, this engine includes an intake distribution means 6 that distributes intake air 5 to a plurality of cylinders 1, 2, 3, and 4; an EGR device 8 that recirculates a portion of the exhaust 7 as recirculated exhaust 7a to the intake air 5 in the intake distribution means 6; an intake pressure sensor 9a that detects the intake pressure 6a of the intake air 5, including the recirculated exhaust 7a, in the intake distribution means 6; an intake pressure guide passage 10 that connects the intake distribution means 6 and the intake pressure sensor 9a; and an electronic control device 12 that controls the engine using parameters 11 including the detected value 6aa of the intake pressure 6a detected by the intake pressure sensor 9a.
[0020] As shown in Figure 4, the intake pressure guide passage 10 comprises a starting end passage portion 10a and a terminal end passage portion 10b. As shown in Figure 2(B), the peripheral wall 10aa of the starting end passage portion 10a and the peripheral wall 6b of the intake air distribution means 6 are integrally formed from the same continuous metal material. In this engine, even when subjected to engine cooling air or engine vibration, the peripheral wall 10aa of the starting end passage portion 10a shown in Figure 4 etc. is less prone to vibration. Therefore, fluctuations in the detected value 6aa of the intake pressure 6a by the intake pressure sensor 9a are suppressed, and the robustness of the intake pressure sensor 9a can be improved. Furthermore, because the peripheral wall 10aa of the starting end passage portion 10a shown in Figure 4 etc. has high heat dissipation properties, water vapor in the intake air 5 within the intake air distribution means 6 condenses in the starting end passage portion 10a, making it difficult for condensed water of strong acid to be generated near the sensor 9, and thus improving the corrosion resistance of the intake pressure sensor 9a.
[0021] As shown in Figure 2(B), the starting end portion 10a of the intake pressure guide passage 10 includes an intake pressure inlet 10ab facing the intake air distribution means 6 and a descending portion 10ac that gradually decreases toward the intake pressure inlet 10ab. In this engine, the highly acidic condensed water that condenses in the starting end portion 10a of the intake pressure guide passage 10 moves from the descending portion 10ac to the intake pressure inlet 10ab by its own weight, making it difficult for highly acidic condensed water to be generated near the intake pressure sensor 9a.
[0022] As shown in Figures 3(B), 3(C), and 3(D), the peripheral wall 10aa of the starting end passage portion 10a protrudes outward from the outer surface 6ba of the peripheral wall 6b of the intake distribution means 6. In this engine, the heat dissipation from the peripheral wall 10aa of the starting end passage portion 10a is high, which promotes the condensation of water vapor within the starting end passage portion 10a.
[0023] As shown in Figures 3(B), 3(C), and 3(D), the peripheral wall 10aa of the starting end passage portion 10a rises upward from the upper surface 6bb of the peripheral wall 6b of the intake distribution means 6. In this engine, the heat dissipation from the peripheral wall 10aa of the starting end passage portion 10a is high, which promotes the condensation of water vapor within the starting end passage portion 10a.
[0024] As shown in Figure 2(A), the intake distribution means 6 is attached to one of the left and right lateral sides 15a of the cylinder head 15 and is formed in a longitudinal shape in the front-rear direction. As shown in Figure 2(A), the peripheral wall 10aa of the starting end passage portion 10a is formed in a longitudinal shape in the front-rear direction along the airflow direction 16a of the engine cooling fan 16 within the air passage 16b of the engine cooling fan 16. In this engine, the distance from the peripheral wall 10aa of the starting end passage portion 10a to the engine cooling air is increased, thus improving the heat dissipation from the peripheral wall 10aa of the starting end passage portion 10a.
[0025] As shown in Figure 2(B), the upper surface 10ad of the peripheral wall 10aa of the starting end passage portion 10a is sloped downward toward the upstream side in the airflow direction 16a of the engine cooling fan 16. In this engine, the engine cooling air blows more effectively onto the upper surface 10ad of the peripheral wall 10aa of the starting end passage portion 10a, thereby improving heat dissipation from the peripheral wall 10aa of the starting end passage portion 10a.
[0026] As shown in Figures 2(A)(B) and 3(B)(C), the intake distribution means 6 has a box-shaped structure with an intake distribution outlet 6c along one of the left and right lateral sides 15a of the cylinder head 15. As shown in Figure 3(C), the upper peripheral edge portion 6ca of the intake distribution outlet 6c is pressed against one of the left and right lateral sides 15a of the cylinder head 15 by the fastening force of the fastener 15b. As shown in Figure 2(C), the peripheral wall 10aa of the starting end passage portion 10a is formed along the upper peripheral edge portion 6ca of the intake distribution outlet 6c. In this engine, even when subjected to engine vibration, the peripheral wall 10aa of the starting end passage portion 10a shown in Figure 4 etc. is less likely to vibrate, and fluctuations in the detected value 6aa of the intake pressure 6a by the intake pressure sensor 9a are suppressed.
[0027] The metal material forming the peripheral wall 10aa of the starting end passage portion 10a of the intake pressure guide passage 10 and the peripheral wall 6b of the intake air distribution means 6, as shown in Figure 2(B), is aluminum or an aluminum alloy. In this engine, the heat dissipation from the peripheral wall 10aa of the starting end passage portion 10a of the intake pressure guide passage 10, as shown in Figure 4, etc., is improved. The peripheral wall 10aa of the starting end passage portion 10a of the intake pressure guide passage 10 and the peripheral wall 6b of the intake air distribution means 6 are made of aluminum or an aluminum alloy and are integrally formed by aluminum die casting.
[0028] As shown in Figure 4, the EGR device 8 comprises an EGR passage 8a, an EGR valve 8e provided in the EGR passage 8a, and a valve upstream passage portion 8d located upstream of the EGR valve 8e. It is equipped with a differential pressure sensor 9b that detects the differential pressure between the exhaust pressure 7b of the valve upstream passage portion 8d and the intake pressure 6a of the intake air distribution means 6 located downstream of the EGR valve 8e. The detected differential pressure value 9ba is included in the parameter 11. In this engine, since the detected differential pressure value 9ba is included as a parameter, the intake air volume is calculated more accurately by the electronic control unit 12, and the opening degree of the intake throttle 24 can be controlled with higher precision. As shown in Figure 4, the valve upstream passage portion 8d is connected to the exhaust outlet of the EGR cooler 8c.
[0029] As shown in Figure 4, the terminal passage portion 10b of the intake pressure guide passage 10 is branched into two, with the intake pressure inlet 9aa of the intake pressure sensor 9a connected to one branch end 10ba, and the intake pressure inlet 9bc of the differential pressure sensor 9b connected to the other branch end 10bb. In this engine, the starting passage portion 10a of the intake pressure guide passage 10 becomes a shared portion for the intake pressure sensor 9a and the differential pressure sensor 9b, eliminating the need to provide multiple starting passage portions 10a of the intake pressure guide passage 10.
[0030] As shown in Figure 7(A), the peripheral wall 10c of the terminal passage portion 10b of the intake pressure guide passage 10 is provided with first to third flexible tubes 10c1, 10c2, and 10c3, and a three-way joint 10d made of a resin or metal material that is harder than the flexible tubes 10c1, 10c2, and 10c3. The intake pressure inlet 10d1 of the three-way joint 10d and the intake pressure outlet 10ae of the starting passage portion 10a of the intake pressure guide passage 10 are connected to the respective ends of the first flexible tube 10c1. One of the intake pressure branch outlets 10d2 of the three-way joint 10d and the intake pressure inlet 9aa of the intake pressure sensor 9a are connected to the respective ends of the second flexible tube 10c2. The intake pressure branch outlet 10d3 of the other end of the three-way joint 10d and the intake pressure inlet 9bc of the differential pressure sensor 9b are connected to the respective ends of the third flexible tube 10c3. The intake pressure outlet 10ae of the starting end passage portion 10a of the intake pressure guide passage 10 is made of iron pipe or steel pipe.
[0031] In this engine, the peripheral wall 10c of the terminal passage portion 10b of the intake pressure guide passage 10 is composed of three short flexible tubes 10c1, 10c2, and 10c3 and a rigid three-way joint 10d. As a result, it is less susceptible to vibration even when subjected to engine cooling air or engine vibrations, and fluctuations in the intake pressure detection value 6aa by the intake pressure sensor 9a and the differential pressure detection value 9ba by the differential pressure sensor 9b are suppressed, thereby improving the robustness of the intake pressure sensor 9a and the differential pressure sensor 9b.
[0032] As shown in Figure 7(A), the intake pressure sensor 9a is positioned directly above the three-way connector 10d, and the differential pressure sensor 9b is positioned adjacent to the intake pressure sensor 9a. In this engine, the second flexible tube 10c2 and the third flexible tube 10c3 can be made shorter, thus further suppressing their vibrations.
[0033] As shown in Figure 2(B), intake port inlets 1a, 2a, 3a, and 4a for each cylinder 1, 2, 3, and 4 are arranged on one left and right side surface 15a of the cylinder head 15 at predetermined intervals in the front-rear direction. An intake port 6e for the intake distribution means 6 is provided at one end in the front-rear direction of the intake distribution means 6. In the front-rear direction, with the intake port 6e side being the rear and the opposite side being the front, the intake port inlet 4a for the fourth cylinder 4 is formed on the side closest to the intake port 6e, and the intake port inlet 1a for the first cylinder 1 is formed on the side furthest from the intake port inlet 6e. The intake port inlet 3a for the third cylinder 3 and the intake port inlet 2a for the second cylinder 2 are arranged in order from the intake port inlet 4a for the fourth cylinder 4 toward the front. As shown in Figure 2(B), the starting end portion 10a of the intake pressure guide passage 10 is equipped with an intake pressure inlet 10ab facing the inside of the intake air distribution means 6, and the intake pressure inlet 10ab is opened at a position along the upper peripheral edge portion 2aa of the intake port inlet 2a of the second cylinder 2 when viewed in a direction parallel to the left and right lateral directions. In this engine, the flow of intake air 5 near the intake pressure inlet 10ab shown in Figure 4, etc., is less affected by the flow of intake air 5 and recirculated exhaust air 7a flowing in from the intake air inlet 6e, so the detected value 6aa of the intake pressure 6a by the sensor 9 is less likely to fluctuate.
[0034] As shown in Figure 4, this engine is equipped with an intake air temperature sensor 19 that detects the intake air temperature within the intake air distribution means 6, which includes the recirculated exhaust 7a. The detected intake air temperature value 6d detected by the intake air temperature sensor 19 is included in the parameter 11. In this engine, because the detected intake air temperature value 6d is included in the parameter 11, the intake air volume can be calculated more accurately by the electronic control unit 12, and the opening degree of the intake throttle 24 can be controlled with higher precision.
[0035] As shown in Figure 2(B), the intake air temperature sensor 19 is positioned between the intake port inlet 1a of the first cylinder 1 and the intake port inlet 2a of the second cylinder 2, when viewed in a direction parallel to the left-right lateral direction. In this engine, the intake air flow 5 near the intake air temperature sensor 19 is less affected by the intake air flow 5 and recirculated exhaust air flow 7a flowing in from the intake port 6e, so the intake air temperature detected value 6d by the intake air temperature sensor 19 is less likely to fluctuate. As shown in Figure 2(B), each cylinder 1, 2, 3, and 4 has one pair of intake port inlets 1a, 2a, 3a, and 4a, and each pair is a direct port.
[0036] As shown in Figure 2(B), the intake air temperature sensor 19 is positioned along the front peripheral edge portion 2ab of the intake port inlet 2a of the second cylinder 2, when viewed in a direction parallel to the left and right lateral directions. In this engine, the flow of intake air 5 near the intake air temperature sensor 19 shown in Figure 4, etc., is less affected by the flow of intake air 5 and recirculated exhaust air 7a flowing in from the intake port 6e, so the intake air temperature detected value 6d by the intake air temperature sensor 19 is less likely to fluctuate.
[0037] As shown in Figure 4, the valve is provided with an exhaust pressure guide passage 17 that connects the upstream passage portion 8d of the valve with the differential pressure sensor 9b. As shown in Figure 6, the exhaust pressure guide passage 17 comprises a starting end passage portion 17a and a terminal end passage portion 17b. The starting end passage portion 17a of the exhaust pressure guide passage 17 has a peripheral wall 17aa formed of a metal pipe and, as shown in Figures 6 and 7(B), has a descending portion 17d that gradually decreases toward the exhaust inlet 17c facing the upstream passage portion 8d of the valve.
[0038] In this engine, even when subjected to engine cooling air or engine vibrations, the peripheral wall 17aa of the starting end passage portion 17a is less prone to vibration, thus suppressing fluctuations in the differential pressure detected value 9ba by the differential pressure sensor 9b and improving the robustness of the differential pressure sensor 9b. Furthermore, the peripheral wall 17aa of the starting end passage portion 17a has high heat dissipation properties, and water vapor in the exhaust gas 7 in the valve upstream passage portion 8d condenses in the starting end passage portion 17a. As a result, condensed water of strong acids is less likely to form near the differential pressure sensor 9b, improving the corrosion resistance of the differential pressure sensor 9b.
[0039] As shown in Figure 6, with one side in the front-rear direction being the front, an engine cooling fan 16 is provided on the front side of the engine, and the peripheral wall 17aa of the starting end passage portion 17a of the exhaust pressure guide passage 17 is formed longitudinally in the front-rear direction along the airflow direction 16a of the engine cooling fan 16 within the airflow passage 16b of the engine cooling fan 16. In this engine, the distance from the peripheral wall 17aa of the starting end passage portion 17a to the engine cooling air is increased, thus improving the heat dissipation from the peripheral wall 17aa of the starting end passage portion 17a.
[0040] The metal pipe forming the peripheral wall 17aa of the starting end passage portion 17a of the exhaust pressure guide passage 17 shown in Figure 6 is a stainless steel pipe. In this engine, both the heat dissipation and corrosion resistance of the peripheral wall 17aa of the starting end passage portion 17a of the exhaust pressure guide passage 17 are high.
[0041] As shown in Figure 6, the peripheral wall 17ba of the terminal passage portion 17b of the exhaust pressure guide passage 17 is made of a flexible tube, one end of which is connected to the exhaust pressure outlet 17ab of the starting passage portion 17a of the exhaust pressure guide passage 17, and the other end is connected to the exhaust pressure inlet 9ac of the differential pressure sensor 9b. In this engine, because the terminal passage portion 17b is a flexible tube, it is easy to connect to the starting passage portion 17a and the differential pressure sensor 9b.
[0042] 1...First cylinder, 1a...Intake port inlet, 2...Second cylinder, 2a...Intake port inlet, 2aa...Upper peripheral portion, 2ab...Front peripheral portion, 3...Third cylinder, 3a...Intake port inlet, 4...Fourth cylinder, 4a...Intake port inlet, 5...Intake, 6...Intake distribution means, 6a...Intake pressure, 6aa...Detected value, 6b...Peripheral wall, 6ba...Outer surface, 6bb...Top surface, 6c...Intake pressure outlet, 6ca...Upper peripheral portion, 6d...Detected value of intake temperature, 6e...Intake inlet, 7...Exhaust, 8...EGR device, 8a...EGR passage, 8d...Valve upstream passage portion, 8e...EGR valve, 7b...Exhaust pressure.
[0043] 9a...Intake pressure sensor, 9aa...Intake pressure inlet, 9b...Differential pressure sensor, 9ba...Detected differential pressure, 9bb...Exhaust pressure inlet, 9bc...Intake pressure inlet, 10...Intake pressure guide passage, 10a...Starting end passage portion, 10aa...Peripheral wall, 10ab...Intake pressure inlet, 10ac...Descending portion, 10ad...Upper surface of peripheral wall, 10ae...Intake pressure outlet, 10b...Ending end passage portion, 10ba...One branch end, 10bb...Other branch end, 10c...Peripheral wall, 10c1...First flexible tube, 10c2...Second flexible tube, 10c3...Third flexible tube, 10d...Three-way joint, 10d1...Intake pressure inlet, 10d2...Intake pressure branch outlet, 10d3...Intake pressure branch outlet, 11...Parameter, 12...Electronic control unit.
[0044] 13... Crankshaft, 14... Cylinder head cover, 15... Cylinder head, 15a... Left and right side, 15b... Fastener, 16... Engine cooling fan, 16a... Airflow direction, 16b... Air passage, 17... Exhaust pressure guide passage, 17a... Starting end passage portion, 17aa... Peripheral wall, 17ab... Exhaust outlet, 17b... End end passage portion, 17ba... Peripheral wall, 17bb... Flexible tube, 17c... Exhaust inlet, 17d... Downward portion, 19... Intake air temperature sensor.
Claims
1. A multi-cylinder engine comprising: an intake distribution means for distributing intake air to multiple cylinders; an EGR device for recirculating a portion of the exhaust as recirculated exhaust into the intake air within the intake distribution means; an intake pressure sensor for detecting the intake pressure within the intake distribution means of the intake air including the recirculated exhaust; an intake pressure guide passage connecting the intake distribution means and the intake pressure sensor; and an electronic control device for controlling the engine using parameters including the detected value of the intake pressure detected by the intake pressure sensor, wherein the intake pressure guide passage comprises a starting end passage portion and a terminal end passage portion, and the peripheral wall of the starting end passage portion and the peripheral wall of the intake distribution means are integrally formed from the same continuous metal material.
2. A multi-cylinder engine according to claim 1, characterized in that the starting end portion of the intake pressure guide passage comprises an intake pressure inlet facing the intake air distribution means and a descending portion that gradually decreases toward the intake pressure inlet.
3. A multi-cylinder engine according to claim 1, characterized in that the peripheral wall of the starting end passage portion is raised outward from the outer surface of the peripheral wall of the intake distribution means.
4. A multi-cylinder engine according to claim 1, characterized in that the mounting direction of the crankshaft is the front-rear direction, the width direction of the engine perpendicular to the front-rear direction is the left-right lateral direction, the direction perpendicular to the front-rear direction and the left-right lateral direction is the up-down direction, and of the up-down direction, the cylinder head cover side is the upper side, and the peripheral wall of the starting end passage portion is raised upward from the upper surface of the peripheral wall of the intake distribution means.
5. A multi-cylinder engine according to claim 4, wherein the intake distribution means is attached to one of the left and right lateral sides of the cylinder head and is formed longitudinally in the front-rear direction, and an engine cooling fan is provided on the front side of the engine with one side in the front-rear direction as the front, and the peripheral wall of the starting end passage portion is formed longitudinally in the front-rear direction along the airflow direction of the engine cooling fan within the air passage of the engine cooling fan.
6. A multi-cylinder engine according to claim 5, characterized in that the upper surface of the peripheral wall of the starting end passage portion is inclined downward toward the upstream side in the direction of airflow of the engine cooling fan.
7. A multi-cylinder engine according to claim 5, wherein the intake distribution means has a box-shaped structure with an intake distribution outlet along one left and right lateral side of the cylinder head, the upper peripheral edge portion of the intake distribution outlet is pressed against one left and right lateral side of the cylinder head by the fastening force of a fastener, and the peripheral wall of the starting end passage portion is formed along the upper peripheral edge portion of the intake distribution outlet.
8. A multi-cylinder engine according to claim 1, characterized in that the metal material forming the peripheral wall of the starting end passage portion of the intake pressure guide passage and the peripheral wall of the intake distribution means is aluminum or an aluminum alloy.
9. A multi-cylinder engine according to claim 1, wherein the EGR device comprises an EGR passage, an EGR valve provided in the EGR passage, and a valve upstream passage portion located upstream of the EGR valve, and comprises a differential pressure sensor for detecting the differential pressure between the exhaust pressure of the valve upstream passage portion and the intake pressure of the intake air distribution means located downstream of the EGR valve, and the detected value of the differential pressure is included in the parameter.
10. A multi-cylinder engine according to claim 9, characterized in that the terminal end of the intake pressure guide passage is branched in a bifurcated manner, with the intake pressure inlet of the intake pressure sensor connected to one branch end and the intake pressure inlet of the differential pressure sensor connected to the other branch end.
11. A multi-cylinder engine according to claim 10, wherein the peripheral wall of the terminal passage portion of the intake pressure guide passage comprises first to third flexible tubes and a three-way joint formed of a resin or metal material harder than the flexible tubes, the intake pressure inlet of the three-way joint and the intake pressure outlet of the starting passage portion of the intake pressure guide passage are respectively connected to the respective ends of the first flexible tube, one intake pressure branch outlet of the three-way joint and the intake pressure inlet of the intake pressure sensor are respectively connected to the respective ends of the second flexible tube, and the other intake pressure branch outlet of the three-way joint and the intake pressure inlet of the differential pressure sensor are respectively connected to the respective ends of the third flexible tube.
12. A multi-cylinder engine according to claim 11, characterized in that the intake pressure sensor is positioned directly above the three-way connector, and the differential pressure sensor is positioned adjacent to the intake pressure sensor.
13. In the multi-cylinder engine described in claim 9, in an in-line four-cylinder engine, the mounting direction of the crankshaft is the front-rear direction, the width direction of the engine perpendicular to the front-rear direction is the left-right lateral direction, the intake port inlets of each cylinder are arranged on one left-right lateral side of the cylinder head at a predetermined interval in the front-rear direction, an intake inlet of the intake distribution means is provided on one end of the intake distribution means in the front-rear direction, with the intake inlet side being the rear side and the opposite side being the front side, the intake port inlet of the fourth cylinder is formed on the side closest to the intake inlet of each cylinder, the intake port inlet of the first cylinder is formed on the side furthest from the intake inlet, and the intake port inlet of the third cylinder and the intake port inlet of the second cylinder are arranged in order from the intake port inlet of the fourth cylinder toward the front. A multi-cylinder engine characterized in that the starting end portion of the intake pressure guide passage is provided with an intake pressure inlet facing the inside of the intake distribution means, and the intake pressure inlet is opened at a position along the upper peripheral edge portion of the intake port inlet of the second cylinder when viewed in a direction parallel to the left and right lateral direction.
14. A multi-cylinder engine according to claim 1, comprising an intake air temperature sensor for detecting the intake air temperature within the intake air distribution means of the intake air including the recirculated exhaust, wherein the detected value of the intake air temperature detected by the intake air temperature sensor is included in the parameter.
15. In the multi-cylinder engine described in claim 14, in an inline four-cylinder engine, the mounting direction of the crankshaft is the front-rear direction, the width direction of the engine perpendicular to the front-rear direction is the left-right lateral direction, the intake port inlets of each cylinder are arranged on one left-right lateral side of the cylinder head at a predetermined interval in the front-rear direction, an intake inlet of the intake distribution means is provided on one end of the intake distribution means in the front-rear direction, with the intake inlet side being the rear side and the opposite side being the front side, the intake port inlet of the fourth cylinder is formed on the side closest to the intake inlet of each cylinder, the intake port inlet of the first cylinder is formed on the side furthest from the intake inlet, and the intake port inlet of the third cylinder and the intake port inlet of the second cylinder are arranged in order from the intake port inlet of the fourth cylinder toward the front. A multi-cylinder engine characterized in that the intake air temperature sensor is positioned between the intake port inlet of the first cylinder and the intake port inlet of the second cylinder, when viewed in a direction parallel to the left-right lateral direction.
16. A multi-cylinder engine according to claim 15, characterized in that the intake air temperature sensor is arranged along the front peripheral edge portion of the intake port inlet of the second cylinder when viewed in a direction parallel to the left-right lateral direction.
17. A multi-cylinder engine according to claim 9, comprising an exhaust pressure guide passage that connects the valve upstream passage portion and the differential pressure sensor, wherein the exhaust pressure guide passage comprises a starting end passage portion and a ending end passage portion, and the starting end passage portion of the exhaust pressure guide passage has a peripheral wall formed of a metal pipe and a descending portion that gradually decreases toward the exhaust inlet facing the valve upstream passage portion.
18. A multi-cylinder engine according to claim 17, wherein one side in the front-rear direction is the front side, and an engine cooling fan is provided on the front side of the engine, and the peripheral wall of the starting end side passage portion of the exhaust pressure guide passage is formed longitudinally in the front-rear direction along the airflow direction of the engine cooling fan within the airflow passage of the engine cooling fan.
19. A multi-cylinder engine according to claim 17, characterized in that the metal pipe forming the peripheral wall of the starting end passage portion of the exhaust pressure guide passage is a stainless steel pipe.
20. A multi-cylinder engine according to claim 19, characterized in that the peripheral wall of the terminal passage portion of the exhaust pressure guide passage is made of a flexible tube, one end of which is connected to the exhaust pressure outlet of the starting passage portion of the exhaust pressure guide passage, and the other end of which is connected to the exhaust pressure inlet of the differential pressure sensor.