JP2500851Y2 - Bypass structure of supercharged engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a bypass structure for bypassing pressurized intake air in an intercooler in a V-type engine equipped with a mechanical supercharger.

(Prior Art) Conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 63-170523, a mechanical supercharger driven by the output of an engine is provided, and pressure is applied by the supercharger. A supercharged engine that supplies intake air to an engine cylinder is well known.

(Problems to be solved by the invention) In such an engine with a supercharger, the temperature of the intake air pressurized by the supercharger rises, and if it is supplied to the cylinder as it is, the charging efficiency of the intake air becomes low. Usually, a water-cooled or air-cooled intercooler is arranged in the intake passage between the supercharger and the engine, and the intake air is cooled by this intercooler.

However, cooling the intake air pressurized by the supercharger with an intercooler is effective mainly in the high rotation and high load regions of the engine where high output is required, and it is effective in the low rotation region and low load region of the engine. If the pressurized intake air is cooled by the intercooler, the intake air temperature may be too low and the atomization of fuel may be impaired.

Therefore, a bypass passage for supplying intake air discharged from the supercharger directly to the cylinder by bypassing the intercooler is provided, and a bypass valve for opening and closing this bypass passage is provided, and the opening of the bypass passage is adjusted by this valve. Therefore, the idea is to adjust the temperature of the intake air supplied to the engine and increase the opening of the bypass passage to raise the intake air temperature to the engine in the low engine speed range and low load range. is there.

At that time, in the V-type engine, if a supercharger and an intercooler are arranged between the left and right banks, in order to supply the intake air from the supercharger to the cylinders of each bank, the bypass passage is provided to each bank. Correspondingly, it is necessary to branch into two and connect the downstream end of each to the cylinder of each bank.

By the way, when supercharging intake air, there is a resonance effect of supercharging by utilizing pulsation of intake air in addition to the supercharger. That is,
The supercharging due to the resonance effect of the intake air is performed by dividing a plurality of cylinders of the engine into a plurality of cylinder groups by dividing them into cylinders of which ignition timings are not continuous (cylinders where the ignition timings are at equal intervals). The independent intake passages of the cylinders are assembled at one upstream end into one collective intake passage (resonance intake passage), and a pressure reversal portion is provided at a predetermined position of the collective intake passage. Then, by matching the phases of the basic pressure wave of intake air generated at the intake port of each cylinder of the cylinder group and the reflected pressure wave inverted at the pressure inversion section in the engine's synchronized rotation range, the pressure inversion section and each cylinder The pressure wave of the intake air that reciprocates between the cylinders resonates in the collective intake passage, and the resonance causes a pressure vibration having a large amplitude due to the pressure oscillations individually generated in each cylinder. Is pushed into the combustion chamber of the cylinder to improve the charging efficiency.

However, in the structure in which the bypass passage is provided as described above, the engine cylinder and the supercharger are connected not only by the main intake passage having the intercooler, but also by the bypass passage. The passage area of the intake passage is substantially increased. Therefore, even if the length of the main intake passage in which the intercooler is arranged is set so that resonance tuning occurs in the low engine speed region, the tuning effect rotation speed of the resonance effect is increased by the increase of the passage area due to the bypass passage. When the engine shifts to the high speed side, a sufficient resonance effect cannot be obtained in the low engine speed range, and torque increase due to the resonance effect cannot be expected.

The present invention has been made in view of the above points, and an object thereof is to prevent the above bypass passage from becoming a passage for resonance by utilizing structural characteristics of a V-type engine having left and right banks. While maintaining the intake resonance resonance speed in the low engine speed range,
It is to secure the low speed torque up of the engine.

(Means for Solving the Problem) In order to achieve this object, in the invention of claim (1), if a supercharger and an intercooler are arranged between the left and right banks of the V-type engine, as described above, Paying attention to the fact that the bypass passage for supplying the intake air from the machine to the cylinders of each bank by bypassing the intercooler is divided into two parts corresponding to each bank, and partitioning members are arranged at the branch parts of both bypass passages. I set it up.

That is, in the present invention, there is a pair of banks facing each other on the left and right, and a mechanical supercharger that pressurizes the intake air and an intercooler that cools the intake air supercharged by the supercharger are provided between the banks. In the engine with a supercharger in which are provided, two bypass passages for supplying the intake air of the supercharger to the cylinders of each bank by bypassing the intercooler are provided.

Further, a partition member for preventing interference of intake pressure waves between the bypass passages is provided at a branch portion of the bypass passages.

(Operation) According to the above configuration, in the present invention, the partition member is arranged at the branch portion of both bypass passages, so that the partition member prevents the interference of the intake pressure wave between both bypass passages. Therefore, even if there is a bypass passage, the resonance effect does not occur there, and the resonance effect occurs in the main intake passage where the intercooler is arranged, and the resonance tuning speed in this intake passage is set to the low engine speed range. by doing,
The low speed torque increase of the engine can be obtained regardless of the bypass passage.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the entire structure of an engine with a supercharger and its intake / exhaust system according to an embodiment of the present invention. In the figure, 1 is a V-type 6-cylinder engine having a pair of banks 1 _L and 1 _R facing each other on the left and right. The engine 1 includes a cylinder block 2 having a substantially V-shaped cross section and a bank 1 _{L of the} cylinder block 2. , 1 cylinder head assembled on _R 3 _L, 3 _R and the cylinder head
Syringe head cover mounted on the upper surface of 3 _L , 3 _R 4 _L ,
4 _R and an oil pan 5 attached to the lower end of the cylinder block 2. The cylinder block 2 of the left bank 1 _L has a first cylinder 6a, a third cylinder 6c and a fifth cylinder 6e, and the cylinder block 2 of the right bank 1 _R has a second cylinder 6b, a fourth cylinder 6d and a sixth cylinder 6e. 6f are formed in order toward the rear (in the figure, each bank
Only the first and second cylinders 6a and 6b at the front end of 1 _L and 1 _R are shown), and the ignition order of these cylinders 6a to 6f is the cylinder number order. Thus, these six cylinders 6a~6f are grouped in banks 1 _L, 1 _R nonconsecutive ignition timing for each cylinder (the ignition timing becomes the equidistant cylinder) two cylinder group are divided by each other.

A piston 9 connected to a crankshaft 8 via a connecting rod 7 is reciprocably fitted into each of the cylinders 6a to 6f, and a combustion chamber 10 is defined by the piston 9 in the cylinders 6a to 6f. There is.

Each of the cylinder heads 3 _L and 3 _R has a downstream end in each cylinder.
Intake ports 11, 11 communicating with the combustion chamber 10 of 6a ~ 6f, and exhaust ports 40, 40 having upstream ends communicating with the combustion chamber 10 are formed, and the downstream end of each intake port 11 is an intake valve 12, The upstream end of each exhaust port 40 is opened and closed by an exhaust valve 41. The exhaust ports 40 of the cylinder heads 3 _L and 3 _R respectively constitute the upstream end portion of the exhaust passage 42, and an exhaust gas purifying converter 43 is provided in the middle of each exhaust passage 42 and a silencer on the downstream side thereof. And 44 are provided.

On the other hand, each intake port 11 constitutes a downstream end portion of the intake passage 13, and the upstream end of the intake passage 13 is connected to the air cleaner 14. Intake passage 13 near this air cleaner 14
An air flow meter 15 is installed in the air flow meter 15. In the intake passage 13 downstream of the air flow meter 15, a throttle body 17 having a throttle valve 16 built therein, a supercharger 18 for pressurizing intake air (intake air), and a supercharger 18 An intercooler 19 for cooling the intake air pressurized by the feeder 18 and two left and right surge tanks 20 _L , 20 _R corresponding to each bank 1 _L , 1 _R of the engine 1 are arranged in this order toward the downstream side. ing.

The supercharger 18 is a mechanical supercharger. That is, the pulley 21 attached to the rotary shaft 18a of the supercharger 18,
A belt 22 is wound around a pulley (not shown) attached to the crankshaft 8 of the engine 1, and the supercharger 18 rotates the rotating shaft 18a by the rotation of the engine 1 to intake air. It is designed to pressurize.

As shown in FIG. 1, the supercharger 18 and the intercooler are provided.
19 are all located between the left and right banks 1 _L and 1 _{R of the} engine 1, and the surge tanks 20 _L and 20 _R are bank 1 _L and 1 _R , respectively.
It is arranged above 1 _R and extends in the direction of each cylinder row. Specifically, the supercharger 18 is arranged in the central portion between the banks 1 _L and 1 _R , and its discharge port 18 b is arranged near the front side (upper side in FIG. 1) between the banks 1 _L and 1 _R. . Meanwhile, the intercooler
19 is disposed in front of the supercharger 18 at the central position between the banks 1 _L and 1 _R , and has an intake inlet (not shown) opening in the left and right central portions of the intercooler 19 and a discharge port 18 b of the supercharger 18. Are connected by one intake passage 13a. Intercooler 19 air outlet in the left and right end portions (not shown) respectively is opened in the left intake outlets of through the intake passage 13b on the front end of the left surge tank 20 _L, also right intake outlet of the right surge tank 20 _R front Are connected to each other via the intake passage 13c. Left surge tank 20 _L of bank 1 _L, 1 _R between the sides serving on the right side three independent intake passages 13d, 13d, ... are connected, these independent intake passages 13d, 13d, ..., respectively downstream end left bank of 1 _L
Are connected to the intake ports 11, 11, ... Of the cylinders 6a, 6c, 6e. Further, three independent intake passages 13e, 13e, ... Are connected to the left side surface between the banks 1 _L , 1 _{R of} the right surge tank 20 _R , and the downstream ends of these independent intake passages 13e, 13e ,. Intake ports 11, 11, ... of cylinders 6b, 6d, 6f of bank 1 _R
It is connected to the.

Then, the supercharger 18 each bank 1 while bypassing the intercooler 19 to intake air discharged from the _L, 1 _R cylinder 6a~6f
Is provided with an intercooler bypass passage 23. As shown in FIG. 1, one end of the bypass passage 23 is connected to the discharge port 18b of the supercharger 18 in a branched state with the intake passage 13a. The bypass passage 23 heads backward between the banks 1 _L and 1 _R and is then branched into the left and right bypass passages 23 _L and 23 _R. The end portion of the left bypass passage 23 _L has a left intake outlet and a left surge of the intercooler 19 described above. the tank 20 _L and the surge tank 20 _L side of the intake passage 13b for connecting and end of the right side bypass passage 23 _R is a surge in the intake passage 13c which connects the right intake outlet and the right surge tank 20 _R of the intercooler 19 It is connected to the tank 20 _R side. Between the branch portion to the discharge port 18b and the left and right bypass passages 23 _L, 23 _R of the supercharger 18 in the bypass passage 23 to open and close the bypass passage 23 by the negative pressure actuator 25 (see FIG. 3) An intercooler bypass valve 24 is provided. By adjusting the opening of the valve 24 according to the operating state of the engine 1, the temperature of the intake air into each combustion chamber 10 is adjusted, and the low rotation speed of the engine 1 is reduced. In the load region, by increasing the opening degree of the valve 24, the amount of intake air that is discharged from the supercharger 18 and is supplied to the combustion chamber 10 bypasses the intercooler 19 and is supplied to the combustion chamber 10. The intake temperature is increased to increase the atomization of fuel.

Further, one end of the supercharger bypass passage 26 is connected to a branch portion of the intercooler bypass passage 23 to the left and right bypass passages 23 _L and 23 _R, and the bypass passage 26 is located between the banks 1 _L and 1 _R in the rearward direction. After extending, it extends downward, and the other end is connected to the intake passage 13f between the supercharger 18 and the throttle body 17 as shown in FIG. A supercharger bypass valve 27 that adjusts the opening degree of the bypass passage 26 by a negative pressure actuator 28 is disposed in the middle of the bypass passage 26.

Further, as shown in FIG. 1, at the branch portion of the intercooler bypass passage 23 to the left and right bypass passages 23 _L and 23 _R , the interference of the intake pressure wave between the bypass passages 23 _L and 23 _R is prevented. A partition 29 as a partition member is provided. The partition wall 29 extends in the front-rear direction from the bypass passage 23 near the intercooler bypass valve 24 to the vicinity of the bypass valve 27 of the supercharger bypass passage 26 as shown in FIG.

Therefore, in the above embodiment, in the high rotation and high load region of the engine 1, the intercooler bypass valve 24 is fully closed and the intake air discharged from the supercharger 18 is intercooled.
After being cooled in 19, is supplied to the combustion chamber 10 of the surge tank 20 _L, 20 through _R each bank 1 _L of the engine 1, 1 in the _R of the cylinder 6 a to 6 f.

On the other hand, in the low rotation range and the low load range of the engine 1, the intercooler bypass valve 24 is controlled to have a large opening. In this state, the resistance of the intake air passing through the bypass passage 23 is smaller than the resistance passing through the intercooler 19, so that the high temperature of the intake air discharged from the supercharger 18 that bypasses the intercooler 19 and is directly supplied to the combustion chamber 10. The amount of inspiration increases. This raises the temperature of the intake air to the combustion chamber 10 and promotes atomization of fuel.

Also, in the low speed range of this engine 1, the left and right banks are
Since the intake order differs between the cylinders 6a to 6f for each 1 _L and 1 _R , the supercharger 18 to the intake passage 13a, the intercooler 19, the intake passage 13
b, 13c, surge tank 20 _L, 20 _R and each independent intake passage 13d, 1
Through 3e each bank 1 _L, 1 sets the effective length of the intake passages 13 leading to the cylinder 6a~6f of _R as resonance tuning between cylinders 6a~6f left and right groups in a low rotation region of the engine 1 occurs By doing so, the intake passage 13 serves as a passage for resonance using the discharge port 18b of the supercharger 18 as a pressure reversal portion, and a resonance effect can be obtained in the intake passage 13. Due to this resonance effect, intake air can be supercharged in the low speed region of the engine 1 to increase the output torque.

At that time, the supercharger 18 and the banks 1 _L and 1 _R are connected to the above intake passage.
Not only 13 but also the left and right bypass passages 23 _L and 23 _{R of the} intercooler bypass passage 23 are connected, and therefore, also in this bypass passage 23, the pressure propagation of the intake air having the branch portion as the pressure reversal portion occurs and the bypass passage 23 _L and 23 _R may become a passage for resonance. However, in this embodiment, the bypass passage 23 is partitioned by the partition wall 29 extending from the vicinity of the intercooler bypass valve 24 to the supercharger bypass passage 26 in the vicinity of the bypass valve 27.
The interference of the intake pressure wave between the left and right bypass passages 23 _L and 23 _R is blocked, and the resonance effect is suppressed. Therefore, the low speed torque of the engine 1 can be increased regardless of the presence of the bypass passage 23.

Although the above-described embodiment is the case of the V-type 6-cylinder engine 1, it is needless to say that the present invention can be applied to V-type engines other than the 6-cylinder engine.

(Effect of the Invention) As described above, according to the present invention, in the V-type engine in which the mechanical supercharger and the intercooler are arranged between both banks, the supercharger and the cylinder of each bank bypass the intercooler. By providing a pair of bypass passages to be connected and a partition member at the branch portions of both bypass passages, an intercooler is provided without causing a resonance effect of intake air between the cylinders of both banks in the bypass passages. This can be generated only in the intake passage, and thus the torque can be increased by the resonance effect in the low engine speed range despite the bypass passage being provided.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a plan view of an engine, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG.
The figure is an explanatory view showing the overall structure of the intake and exhaust system of the engine. 1 …… Engine 1 _L , 1 _R …… Bank 6a to 6f …… Cylinder 10 …… Combustion chamber 13 …… Intake passage 18 …… Supercharger 19 …… Intercooler 23,23 _L , 23 _R …… Intercooler bypass Passage 24 …… Intercooler bypass valve 29 …… Partition wall (partitioning member)

Claims (1)

(57) [Scope of utility model registration request] 1. A mechanical supercharger for pressurizing intake air, and an intercooler for cooling intake air supercharged by the supercharger, having a pair of banks facing each other on the left and right sides. In the installed engine with a supercharger, two bypass passages for supplying the intake air of the supercharger to the cylinders of each bank by bypassing the intercooler are provided, and the bypass portions between the bypass passages are provided between the bypass passages. A bypass structure for an engine with a supercharger, characterized in that a partition member is provided to prevent interference of intake pressure waves in the engine.