Internal combustion engine having improved fuel pump configuration, and vehicle including same

Abstract

An engine-mounted mechanical fuel pump for an internal combustion engine contributes to a stable operation of the engine, a reduction in the weight of the engine, and a reduction in the pump drive loss. The engine includes a cylinder head provided with intake ports and exhaust ports therein, and fuel injection valves for injecting fuel into the inside of a tubular intake air routing assembly connected to the intake ports. A fuel pump is provided on the rear side of a cylinder block and on the upper side of a crankcase, in an arrangement where the intake ports are formed to extend rearwardly and the exhaust ports are formed to extend forwardly from the cylinder head. In one embodiment, the fuel pump is provided on the front side of the cylinder block, where the intake ports are formed to extend forwardly and the exhaust ports are formed to extend rearwardly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side plan view of a motorcycle on which is mounted an internal combustion engine provided with a fuel pump that supplies fuel thereto according to the present invention.

FIG. 2 is a right side sectional view of the engine of FIG. 1, showing the fuel pump disposed on a side of the cylinder head that is opposed to the exhaust pipe.

FIG. 3 is a sectional view of the engine of FIG. 1, showing the cylinder head and cylinder block.

FIG. 4 is a sectional view of the engine of FIG. 1, showing the transmission.

FIG. 5 is a sectional view of the engine of FIG. 1, showing the starter motor relative to the crankshaft and main shaft.

FIG. 6 is an enlarged view of a portion of the motorcycle of FIG. 1, showing the mounting relationship of an air cleaner chamber and a fuel tank.

FIG. 7 is a block diagram of a fuel supply system of the engine of FIG. 1.

FIG. 8 is an enlarged sectional view of a portion of the engine of FIG. 1, showing the structure of the fuel pump according to a first embodiment.

FIG. 9 is a right side sectional view of an engine showing a fuel pump arrangement according to a second embodiment of the invention.

FIG. 10 is a left side sectional view of an engine showing a fuel pump arrangement according to a third embodiment of the invention.

FIG. 11 is a sectional view of a portion of the engine of FIG. 10 showing the structure of the fuel pump according to the third embodiment.

FIG. 12 is a sectional view of an engine showing a fuel pump arrangement according to a fourth embodiment of the invention.

FIG. 13 is a right side sectional view of a portion of the engine of FIG. 12 showing the structure of the fuel pump according to the fourth embodiment.

FIG. 14 is a right side sectional view of an engine showing a fuel pump arrangement according to a fifth embodiment of the invention.

FIG. 15 is a sectional view of a portion of the engine of FIG. 14 showing the structure of the fuel pump according to the fifth embodiment.

FIG. 16 is a sectional view of a portion of an engine showing the structure of a fuel pump according to a sixth embodiment.

FIG. 17 is a right side sectional view of an engine showing a fuel pump according to a seventh embodiment.

FIG. 18 is a right side sectional view of an engine showing a fuel pump according to a modified embodiment of the seventh embodiment.

Claims

1. An internal combustion engine comprising: a crankcase having a hollow crank chamber formed therein;a crankshaft rotatably supported on the crankcase;a cylinder block having a cylinder chamber provided therein, said cylinder block provided on an upper side of, and connected to said crankcase;a piston slidably disposed in the cylinder chamber and operatively connected to said crankshaft;a cylinder head disposed on an upper side of, and connected to, said cylinder block so as to cover said cylinder chamber, the cylinder head comprising an intake port extending in a first direction toward a first side of said cylinder block, and an exhaust port extending in a second direction that is substantially opposed to the first direction, wherein said intake port and said exhaust port are respectively capable of selectively communicating with a combustion chamber disposed in said cylinder chamber between said cylinder head and said piston;an intake air routing assembly connected to said intake port;a first fuel injector provided on said intake air routing assembly for injecting fuel into said intake air routing assembly during engine operation; anda fuel pump provided on the first side of said cylinder block, and on an upper portion of said crankcase, wherein said fuel pump is mechanically driven and supplies fuel to said fuel injector during engine operation.

2. The internal combustion engine as set forth in claim 1, wherein the fuel pump further comprises a fuel pump drive shaft, and wherein the engine further comprises: a camshaft rotatably supported on said cylinder head;a cam drive mechanism contained in a timing chamber formed inside lateral portions of said cylinder block and said cylinder head, respectively, the cam drive mechanism adapted to transmit rotation of said crankshaft to said camshaft during engine operation, anda pump drive mechanism for transmitting the rotation of said crankshaft to the fuel pump drive shaft; wherein:one end part of the crankshaft projects outside of the crankcase,the cam drive mechanism comprises a drive element, the drive element disposed on the one end part of the crankshaft, andsaid pump drive mechanism comprises:a pump drive sprocket provided at said one end part of said crankshaft and located on an axially inner portion thereof relative to said drive element of said cam drive mechanism;a pump driven sprocket provided on said drive shaft of said fuel pump; anda flexible belt wrapped around and interconnecting said pump drive sprocket and said pump driven sprocket.

3. The internal combustion engine as set forth in claim 1, wherein said intake air routing assembly comprises: a throttle body, one end of the throttle body being operatively connected to the intake port;an air feed pipe, the air feed pipe extending from another end of the throttle body, andan air cleaner housing having an air cleaner chamber formed therein,wherein a portion of the air feed pipe is enclosed within the air cleaner chamber, and wherein the first fuel injector is mounted to an upper surface of the air cleaner housing and is oriented to direct fuel towards an inlet of the air feed pipe.

4. The internal combustion engine as set forth in claim 3, wherein said engine further comprises a second fuel injector mounted on the throttle body, the second fuel injector configured to inject fuel directly into the throttle body during engine operation.

5. The internal combustion engine as set forth in claim 1, wherein the fuel pump comprises: a pump body, the pump body having an opening formed therein, an inlet port permitting communication between a fuel input passage and the opening, and a discharge port permitting communication between a fuel discharge passage and the opening;a pump drive shaft rotatably supported inside the pump body, a first end of the pump drive shaft comprising a cam surface; anda plunger mounted in an opening of the pump body so as to reciprocate with respect to the pump body, the plunger extending from the pump body, the plunger being biased to abut against the cam surface,wherein the fuel pump is configured such that rotary motion of the pump drive shaft results in reciprocating rectilinear motion of the plunger, whereby fuel is drawn in through the inlet port and discharged from the discharge port.

6. The internal combustion engine as set forth in claim 5, wherein an axis of the plunger is substantially parallel to an axis of the pump drive shaft.

7. The internal combustion engine as set forth in claim 5, wherein the fuel pump further comprises a pump driven sprocket connected to a second end of the pump drive shaft, and wherein the pump driven sprocket is operatively connected to the crankshaft, whereby the fuel pump is mechanically driven by rotation of the crankshaft.

8. The internal combustion engine as set forth in claim 1, the fuel pump further comprising a fuel pump drive shaft and a pump sprocket mounted on the fuel pump drive shaft, and the engine further comprising: a camshaft rotatably supported on said cylinder head,a cam drive mechanism contained in a timing chamber formed inside lateral portions of said cylinder block and said cylinder head, the cam drive mechanism configured to transmit rotation of said crankshaft to said camshaft during engine operation, anda pump drive mechanism for transmitting the rotation of said crankshaft to the fuel pump drive shaft; whereinsaid cam drive mechanism comprises: a cam drive sprocket provided on said crankshaft;a cam driven sprocket provided on said camshaft, anda cam timing belt wrapped around and interconnecting said cam drive sprocket and said cam driven sprocket;wherein said pump drive mechanism obtains a driving force from the pump sprocket, and the pump sprocket is driven by said cam timing belt.

9. The internal combustion engine as set forth in claim 1, the engine further comprising: a cam formed integrally with an outer periphery of a web of said crankshaft; anda pump drive mechanism for transmitting rotation of said crankshaft to said fuel pump to thereby drive said fuel pump, whereinsaid pump drive mechanism comprises a rod abutting on said cam and extending in a direction orthogonal to the axis of said crankshaft.

10. The internal combustion engine as set forth in claim 1, the fuel pump further comprising a fuel pump drive shaft, and the engine further comprising: a power transmission device for transmitting rotation of said crankshaft to a drive train component operatively connected to a wheel or wheels; anda pump drive mechanism, the pump drive mechanism transmitting the rotation of said crankshaft to the fuel pump drive shaft during engine operation, whereinsaid power transmission device comprises: a main shaft disposed in parallel to said crankshaft;a primary speed reduction transmission path that transmits the rotation of said crankshaft to said main shaft through speed reduction; anda clutch mechanism provided on said main shaft so as to connect and disconnect said primary speed reduction transmission path and the crankshaft,wherein said primary speed reduction transmission path comprises: a primary speed reduction drive element connected to said crankshaft; anda primary speed reduction driven element rotated with a speed reduction relative to said primary speed reduction drive element, the primary speed reduction driven element provided so as to rotate relative to said main shaft and connect to an upstream-side member of said clutch mechanism,and wherein said pump drive mechanism comprises:a pump drive sprocket which rotates integrally with said primary speed reduction driven element; a pump driven sprocket provided on said drive shaft of said fuel pump; anda flexible pump drive belt wrapped around and interconnecting said pump drive sprocket and said pump driven sprocket.

11. A vehicle comprising a vehicle frame, an internal combustion engine mounted on the vehicle and connected to the vehicle frame, and a fuel pump for supplying fuel to the engine, the engine comprising: a crankcase having a crank chamber formed therein;a crankshaft rotatably supported on the crankcase;a piston operatively connected to the crankshaft;a cylinder block disposed on said vehicle frame so as to be operatively exposed to air flow during vehicle operation, the cylinder block fixedly attached to said crankcase and comprising a cylinder chamber in which the piston is slidably disposed, with an axis of said cylinder chamber inclined toward a front side of the vehicle;a cylinder head connected to said cylinder block so as to cover said cylinder chamber, the cylinder head disposed on said vehicle frame so as to be exposed to air flow during vehicle operation, the cylinder head provided with an intake port formed therein and extending toward a vehicle rear upper side and an exhaust port formed therein and extending toward a vehicle front lower side, said intake port and said exhaust port respectively capable of selectively communicating with a combustion chamber;an intake air routing assembly connected to said intake port; anda fuel injector provided on said intake air routing assembly for injecting fuel into said intake air routing assembly,wherein said fuel pump is a mechanically driven fuel pump for supplying fuel to said fuel injector, and said fuel pump is provided on the vehicle front upper side of said cylinder head.

12. The vehicle as set forth in claim 11, wherein the fuel pump further comprises a fuel pump drive shaft, and the engine further comprises: a camshaft rotatably supported on said cylinder head; anda pump drive mechanism for transmitting rotation of said crankshaft to the fuel pump drive shaft, andsaid pump drive mechanism comprises: a pump drive gear provided on said camshaft; anda pump driven gear provided on said fuel pump drive shaft, the pump driven gear intermeshed with said pump drive gear.

13. The internal combustion engine as set forth in claim 11, wherein the fuel pump comprises: a pump body, the pump body including an opening formed therein, an inlet port permitting communication between with a fuel input passage and the opening, and a discharge port permitting communication between a fuel discharge passage and the opening;a pump drive shaft rotatably supported inside the pump body, the pump drive shaft comprising a cam surface; anda plunger mounted in an opening of the pump body so as to reciprocate with respect to the pump body, the plunger extending from the pump body, the plunger being biased to abut against the cam surface,wherein the fuel pump is configured such that rotary motion of the pump drive shaft results in reciprocating rectilinear motion of the plunger, whereby fuel is drawn in the inlet port and discharged from the discharge port.

14. The internal combustion engine as set forth in claim 13, wherein an axis of the plunger is substantially parallel to an axis of the pump drive shaft.

15. The internal combustion engine as set forth in claim 13, wherein an axis of the plunger is substantially perpendicular to an axis of the pump drive shaft.

16. An internal combustion engine comprising: a cylinder block provided with a cylinder chamber formed therein;a cylinder head provided on the upper side of, and connected to, said cylinder block so as to cover said cylinder chamber, the cylinder head comprising an intake port and an exhaust port which communicate with a combustion chamber;an intake air routing assembly connected to said intake port;a fuel injector provided at said intake air routing assembly and injecting a fuel into the inside of said intake air routing assembly, anda fuel pump for delivering fuel to the engine, said fuel pump disposed on a first side of said cylinder block, and is disposed below said intake gas pipe member;