JPH03149317A - Vehicle engine - Google Patents

Abstract

PURPOSE:To substantially equalize lengths of respective suction pipes by providing the suction pipes where the minimum distance between connecting ports of a surge tank and each cylinder becomes shorter the corresponding suction pipe is projected longer toward a forward side of a cylinder head. CONSTITUTION:A surge tank 9 which is shorter than a cylinder head 2 is placed above the cylinder head 2 to extend toward a crankshaft, and the surge tank 9 is connected to each cylinder with suction pipes 4a-4d respectively. Then the suction pipes 4a-4d are projected toward the forward side of an engine E by different distances respectively. Namely, the suction pipe 4a to connect the shortest distance between the connecting ports 2a and 9a is projected for ward by the largest length, and the projected amount is sequentially decreased. The suction pipe 4d to connect the longest distance between the connecting ports 2d and 9d is projected forward by the smallest length. By this method, the suction pipes 4a-4d are compactly housed in a narrow engine room and moreover the length of the suction pipes 4a-4d respectively can be substantially equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a multi-cylinder vehicle engine having a surge tank in its intake system.

[Prior art]

When connecting a surge tank with a volume that is the intake pipe,
Intake interference between cylinders can be eliminated, thereby improving engine performance.

When the surge tank is provided in a vehicle equipped with a multi-cylinder engine, it is desirable to arrange it above the cylinder head and along the crankshaft direction in order to save space in the engine room. However, if this surge tank is made too long, the engine response characteristics when the throttle valve is opened will deteriorate.

Therefore, it is better to make the length of the surge tank as short as possible within the range that maintains the effect of improving engine performance.

On the other hand, in order to ensure that the output of a multi-cylinder engine is even for each cylinder, it is desirable to ensure that the lengths of the intake pipes that connect the surge tank and each cylinder are not unequal between the cylinders. .

However, if the length of the surge tank is shortened as mentioned above, the pitch of the intake pipe connection port on the surge tank side and the pitch of the intake pipe connection port on the engine side will be different, so the engine space will be expanded. Without this, it becomes extremely difficult to align each intake pipe length to the same length.

[Problem to be solved by the invention]

An object of the present invention is to store the surge tank and intake pipe compactly in the engine room in a vehicle equipped with a multi-cylinder engine, maintain the best engine response characteristics due to the surge tank, and reduce the output of each cylinder to the cylinder. An object of the present invention is to provide a vehicle engine that can be balanced at different times.

[Means for Solving the Problems] The present invention, which achieves the above object, is a vehicle in which a multi-cylinder engine is mounted horizontally, in which a surge tank that is shorter than the cylinder head length is arranged in the upper part of the cylinder head so as to extend in the crankshaft direction. At the same time, the surge tank and each cylinder are connected by an intake pipe, and the intake pipe at the position where the shortest distance between the connection port between the surge tank and each cylinder is shortest is made to protrude longer toward the front side of the cylinder head. This is characterized in that the lengths of the intake pipes are substantially equal.

By arranging the surge tank and connecting the intake pipes in this way, the surge tank and intake pipes can be stored compactly in the engine room, while maintaining the best engine response characteristics due to the surge tank, and increasing the output of each cylinder. can be balanced for each cylinder.

1 Embodiment] The figure shows an embodiment of the present invention installed in a front-wheel drive vehicle.

The direction of arrow P is the traveling direction of the vehicle body, and a four-cylinder engine E is mounted horizontally with its crankshaft perpendicular to the direction of arrow F. B is a bonneva that covers the upper part of the engine E.

In the above engine, 1 is a cylinder block, 2 is a cylinder head, and 3 is a combustion case.

One end of the spark plugs 14, 14, 1.4.14 of each cylinder protrudes from the upper part of the horizontally placed cylinder head 2, and a surge tank 9 is installed parallel to the row of spark plugs along the crankshaft direction. It is provided.

On the front surface of the cylinder head 2, four intake pipes 4a, 4b, 4c, and 4d extending from the surge tank 9 are connected to each cylinder, and fuel injection valves 8a, 811.8C, 8d is attached. Further, exhaust pipes 5a, 5b, 5 are provided on the rear surface of the cylinder head 2.
c and 5d are connected, and these are converged into the exhaust pipe 6 of the body via the turbochart shaft.

Also, 10 is an air cleaner, 11 is an intertara, 1
2 is a throttle body, 13 is a breather case, and 17 is an oil inlet. The throttle body 12 is connected to the suction side of the surge tank 9, and has a throttle valve 12a provided inside thereof. Air is sucked in from the air cleaner 10 according to the opening degree of the throttle valve 12a, and the air is supercharged by the turbocharger shaft, cooled by the intercooler 11, passed through the throttle body 12, the surge tank 9, and then sent to each intake pipe. It is sent to each cylinder from 4a, 4b, 4c4d.

In addition, an idle speed control valve 1 is provided at the other end of the surge tank 9.
5 are connected. This idle speed control valve 15 is connected to the surge tank 9 and the air cleaner 1 via a bypass pipe 16.
There is direct communication between the The idle speed control valve 15 has its throttle area adjusted by receiving a control signal from a control section (not shown) during idling operation.
The idling rotation is maintained constant by adjusting the amount of air introduced from the air cleaner 1o.

Intake pipes 4a, 4b, 4c in the engine E.

46 are of equal length. On the other hand, in order to speed up the engine response characteristics, the length of the surge tank 9 is shorter than the length of the cylinder head 2 (which is the length in the crankshaft direction).

For this reason, connection ports 2a and 2b of two examples of cylinder heads
.

2c, 2d pitch and connection port 9a on the surge tank 9 side,
Regarding the pinches of 9b, 9c, and 9d, the latter pinch is larger, and as a result, the corresponding shortest distances between the cylinder head 2 side and the surge tank 9 side are different from each other. It has become a thing. That is, the shortest distance between connection ports 2a and 9a is the shortest, and the distance between adjacent connection ports becomes longer in order, and the last distance between 2d and 9d is the longest.

・Although the shortest distances between the connection ports are different in this way, in order to harmonize the relationship that the lengths of the intake pipes 4a, 4b, 4c, and 4d that connect these ports are mutually equal,
Each of the intake pipes 4a, 4b, 4c, and 4d is made to protrude toward the front of the engine E by different distances. That is, the intake pipe 4a that connects the shortest section 2a-9a protrudes forward the most, and the amount of protrusion gradually decreases until the intake pipe 4d that connects the longest section 2d-9d protrudes the least amount. There is. For this reason, each intake pipe 4a, 4b, 4c,
The common point of contact with the outer surface of the bent portion 4d is in an inclined relationship such that it approaches the crankshaft closer to the intake pipe 4d.

With such a connection configuration, the four intake pipes 4a, 4b
, 4c, and 4d are compactly housed in a narrow engine room, maintain the best engine response characteristics based on the surge tank 9, and balance the output of each cylinder.

In addition, although the above-mentioned embodiment explained the case where the engine is mounted horizontally, the present invention can also be applied when the engine is mounted vertically.

〔Effect of the invention〕

As described above, in a vehicle equipped with a horizontally mounted multi-cylinder engine, a surge tank shorter than the length of the cylinder head is arranged above the cylinder head so as to extend in the crankshaft direction, and the surge tank and each cylinder are connected to each other. The intake pipes are connected to each other by an intake pipe, and the intake pipe at the position where the shortest distance between the connection port between the surge tank and each cylinder is They are essentially the same. Therefore, it is possible to compactly store the surge tank and the intake pipe in the engine room, maintain the best engine response characteristics due to the surge tank, and balance the output of each cylinder for each cylinder.

[Brief explanation of the drawing]

The drawings show a vehicle engine according to an embodiment of the present invention; FIG. 1 is a plan view of the engine, FIG. 2 is a side view, and FIG. 3 is a front view. E...Engine, 2...Cylinder head, 4a, 4
b, 4c, 4d...Intake pipe, 9...Surge tank,
2a+2b, 2e, 2d; 9a, 9b, 9c
, 9d - Connection port.

Claims (1)

[Claims] In a vehicle equipped with a multi-cylinder engine, a surge tank shorter than the length of the cylinder head is arranged above the cylinder head so as to extend in the direction of the crankshaft, and the surge tank and each cylinder are connected by an intake pipe, A vehicle engine in which the intake pipes at positions where the shortest distance between the surge tank and the connection port of each cylinder is short are made to protrude longer to the side of the cylinder head, so that the mutual lengths of the intake pipes are substantially equal.