JP2001090545A - Four-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a four-cycle engine with a long and compact inlet pipe. SOLUTION: A four-cycle engine comprises an engine body 2 having a cylinder axis C inclined to the side of an exhaust system E in view of an engine 1 in the direction a crank shaft center and an inlet pipe 9 having one end connected to a cylinder head 4 and the other end connected to a surge tank 10 in a bent form, the inlet pipe 9 being as high as the engine body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the structure of a four-stroke engine.

[0002]

2. Description of the Related Art A four-stroke engine for a four-wheeled vehicle has a lower engine speed than, for example, a motorcycle, and therefore requires a longer intake pipe length. Therefore, it was difficult to produce a compact engine while obtaining sufficient torque. For example, if the engine is tilted to lower the overall height, the overall width will be wide, and if the engine is raised upright to reduce the overall width, the engine height will increase,
The intake pipe length could not be increased.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a compact four-stroke engine having a long intake pipe length.

[0004]

According to a first aspect of the present invention, when the engine is viewed in the direction of the crankshaft center, the cylinder axis C is inclined toward the exhaust system E side. And an intake pipe 9 having one end connected to the cylinder head 4 and the other end bent and connected to the surge tank.
The height of the engine body 2 is substantially the same as the width W, and the width Wo of the oil pan 7 and the intake system are substantially equal to each other. I
The width Wi of the engine body 2 is designed to be substantially the same, and the invention according to claim 3 is characterized in that the crankshaft 15 is positioned substantially at the center of the entire width of the engine body 2 in claim 1 or 2. 5. The method according to claim 4, wherein
The invention described in any one of claims 1 to 3 is characterized in that auxiliary machines 11, 12, 17 are arranged below the intake system I. Note that the numbers added to the above configuration are compared with the drawings to facilitate understanding of the present invention, and the configuration of the present invention is not limited by this.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of a four-stroke engine according to the present invention. FIG. 1 is a side view, FIG. 2 is a front view seen from the X direction in FIG. 1, and FIG. 3 is a view seen from the C direction in FIG. FIG. Although this embodiment shows an example in which the present invention is applied to a three-cylinder engine, the number of cylinders is arbitrary.

In FIG. 1, an engine 1 is an in-line three-cylinder fuel injection type four-cycle engine, and an engine body 2
The cylinder axis C is inclined toward the exhaust system E side. As shown in FIG. 2, the engine body 2 is connected to a cylinder block 3, a cylinder head 4 connected to an upper part of the cylinder block 3, a head cover 5 covering the cylinder head 4, and a lower part of the cylinder block 4. It comprises a crankcase 6 and an oil pan 7 connected to a lower part of the crankcase 6.

By employing the structure in which the engine main body 2 is inclined as described above, a space is created on the intake system I side of the engine main body 2, and in this space, an intake pipe 9, a surge tank 10, a cooling water pump 11, Alternator 12,
Auxiliary equipment such as a belt tensioner 13 is provided, while a drive shaft D is provided in a space on the exhaust system E side (however, in the case of front-wheel drive with the engine laterally mounted). The cooling water pump 11, the alternator 12, and the belt tensioner 13 are connected to a driving pulley 16 fixed to a crankshaft 15 by a belt 14. An air conditioner compressor 17 and a belt tensioner 19 are provided as optional accessories.
6. Reference numeral 21 denotes an actuator of the tumble control valve.

In FIG. 1, that is, when the engine is viewed in the direction of the crankshaft center, the intake pipe 9 has one end connected to the cylinder head 4 and extends obliquely upward from the intake port of the cylinder head 4. After being extended horizontally at substantially the same height as that of the engine body 2, the engine body 2 is bent in an arc shape so as not to protrude from the right end (ie, the right end of the oil pan 7) in the drawing, and is connected to the surge tank 10. A throttle body 22 and an intake intake pipe 23 are connected to the surge tank 10.

With the above configuration, the height H and the width W of the engine body 2 are substantially the same, and the width Wo of the oil pan 7 and the width Wi of the intake system I are substantially the same. Further, the crankshaft 15 is configured to be located substantially at the center of the entire width of the engine body 2.

Next, the mounting structure of the alternator 12 and the air conditioner compressor 17 will be described. A mounting bracket 24 extending in the width direction of the engine body 2 is formed integrally with the cylinder block 3. A pair of mounting brackets 25 and 26 extending in the width direction of the engine body 2 are integrally formed on the upper and lower surfaces of the oil pan 7. The alternator 12 is fastened to the mounting bracket 24 on the cylinder block 3 side and the mounting bracket 25 on the oil pan 7 side by bolts 27 and 29, respectively. The air conditioner compressor 17 is provided with bolts 3 on the mounting brackets 25 and 26 on the oil pan 7 side.
It is fastened by 0.

As shown in FIG. 3, a recess 7a is formed in the oil pan 7, and an oil filter 31 is provided in the recess 7a. The oil filter 31 is fixed to the oil pan 7 by bolts 32. As shown in FIG. 1, the bolt 32 plays a role of fixing the oil pan 7 to the crankcase 6 and the cylinder block 3 near the mounting bracket 25.

[0012]

As is apparent from the above description, according to the first to third aspects of the present invention, the intake system is provided in a space generated by tilting the engine.
A compact four-stroke engine having a small size, light weight, a long intake pipe length, and therefore having sufficient torque can be provided at low cost. According to the invention of claim 4, a space generated by tilting the engine is provided. Auxiliary equipment can be arranged in the engine, and the engine can be made more compact.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a four-cycle engine of the present invention.

FIG. 2 is a front view as viewed from an X direction in FIG. 1;

FIG. 3 is a bottom view as viewed from a direction C in FIG. 1;

[Explanation of symbols]

 C: Cylinder axis E: Exhaust system I: Intake system 2: Engine body 4: Cylinder head 7: Oil pan 9: Intake pipe 10: Surge tank

Claims (4)

[Claims] When the engine is viewed in the direction of the crankshaft center,
An engine body having a cylinder axis inclined toward the exhaust system, an intake pipe having one end connected to the cylinder head and the other end bent and connected to the surge tank, and having a height of the intake pipe. A four-stroke engine characterized by being substantially the same height as the engine body. 2. The four-stroke engine according to claim 1, wherein the height and the width of the engine body are substantially the same, and the width of the oil pan and the width of the intake system are substantially the same. 3. The four-stroke engine according to claim 1, wherein the crankshaft is located substantially at the center of the entire width of the engine body. 4. The four-stroke engine according to claim 1, wherein an auxiliary machine is provided below the intake system.