JPH0745822B2 - Intake system structure of engine with mechanical supercharger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intake system structure of an engine with a mechanical supercharger, which is provided with a bypass passage for controlling supercharging pressure.

(Prior Art) Conventionally, as described in, for example, Japanese Utility Model Publication No. 61-5330, there is known a V-type engine in which a mechanical supercharger is arranged between the left and right banks above the engine.

By the way, the supercharging pressure control in an engine with a mechanical supercharger is generally performed by controlling the amount of air bypassing the supercharger as shown in FIG. 4 of Japanese Utility Model Laid-Open No. 61-78250. Is. Further, in such bypass control, there is a problem that the drive loss is large and the intake air temperature rises. Therefore, as described in Japanese Utility Model Laid-Open No. 61-78250, a throttle valve is installed upstream of the supercharger. It is also proposed that the bypass passage itself be installed, and a supercharging pressure control valve is provided between the throttle valve and the supercharger to directly control the amount of air entering the supercharger. Especially, it is effective to secure the amount of filling in the non-supercharging area and to facilitate the supercharging pressure control especially in the low load area. . In that case, in the case where the mechanical supercharger is arranged in the space above the engine as in the V-type engine, how to make the intake system of the engine including the supercharger main body and the bypass passage compact, that time,
An important technical issue is how to construct an intake system with low intake resistance.

In order to perform supercharging pressure control by bypass control, a bypass passage must be provided, and the bypass passage is required to have a minimum line resistance. That is, when controlling the boost pressure by the amount of bypass air,
If the pipeline resistance is large, the back pressure of the supercharger is correspondingly increased, and there is a problem that the drive loss of the supercharger is increased. Further, such an increase in drive loss becomes a problem even in a low load range where the bypass valve is fully opened. Further, in the case where the drive of the supercharger is stopped in the non-supercharging region and the filling amount is secured by the bypass passage, there is a problem that the filling efficiency is lowered when the conduit resistance of the bypass passage is large, and therefore, Again, the conduit resistance is required to be small. As described above, the bypass passage needs to have a small conduit resistance (intake resistance), and the technical problem is how to shorten the bypass passage and reduce the number of bends. In addition, shortening the bypass passage and reducing the number of bends in this way also leads to downsizing of the intake system.

(Object of the Invention) The present invention has been made to solve such a problem, and in an engine in which a mechanical supercharger is arranged above an engine body, an engine including a supercharger and a bypass passage thereof is provided. The object is to make the intake system compact and suppress an increase in intake resistance.

(Structure of the Invention) The present invention solves the above technical problems by the following structure and an appropriate piping structure of the bypass pipe. That is, the intake system structure of the engine with a mechanical supercharger according to the present invention is provided with an inlet opening in the axial direction at one end in the rotor axial direction and opening in the rotor radial direction at the other end in the rotor axial direction. In the upper part of the engine, the Rishorum-type supercharger having a discharge portion is arranged so that the inlet portion is opened rearward and the discharge portion is opened upward, and the discharge portion is extended upward, and the upper portion thereof is It is bent laterally from the middle and connected to the intercooler, and the suction pipe downstream of the air cleaner is connected to the inlet of the supercharger to extend the suction pipe rearward in the axial direction of the rotor, It is characterized in that a bypass pipe is provided so as to connect a portion extending upward and a portion extending in the rotor axial direction at the rear of the suction pipe of the suction pipe in a substantially L shape.

(Operation) The above-mentioned configuration effectively utilizes the opening direction of the inlet portion and the discharge portion of the Rishorum type supercharger and the portion connected or extended to the inlet portion and the discharge portion,
As a result, the bypass passage is short and has only one bent portion. Therefore, the intake resistance is reduced, the back pressure of the supercharger is reduced, the drive loss is reduced, and the non-supercharging region is reduced. It becomes easy to secure the filling amount by bypass air in step 3, and it becomes easy to make the intake system compact.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 schematically shows a system of mechanical supercharging of an engine according to an embodiment of the present invention. In this system, the intake port 102 of the engine 101 and the air cleaner 10
A mechanical supercharger 105 is arranged in an intake passage 104 that communicates the three. This mechanical supercharger 105 is based on a so-called Rishorum type screw compressor that is a combination of a four-leaf male rotor and a female rotor having six grooves. Is connected to an air-cooled intercooler 106. Further, a throttle valve 107 is provided upstream of the supercharger 105, and a bypass passage 108 that connects the downstream side of the throttle valve 107 and the upstream side of the intercooler 106 and bypasses the supercharger 105 is formed. Intake passage 1
An auxiliary throttle valve 109 is provided immediately downstream of the branch point of the bypass passage 108 of 04. The auxiliary throttle valve 109
Are connected to a throttle valve lever 112 via an auxiliary throttle valve lever 110 and a grooved rod 111. Auxiliary throttle valve 109 when throttle valve 107 opens to a predetermined opening
Begins to open. Further, the bypass passage 108 is provided with a diaphragm type bypass type 113. In the non-supercharging region, the bypass valve 113 is opened to allow natural aspiration without the supercharger 105. The supercharger 105 is connected to a driving side variable pulley (not shown) via an electromagnetic clutch 114 and a centrifugal variable pulley 115. The intake passage 104 also includes a fuel injector 116 adjacent to the intake port 102.
Is provided, and the air flow meter 1 is provided downstream of the air cleaner 103.
17 are provided.

The electromagnetic clutch 114 is disengaged in the low rotation / low load range as shown in FIG. 2, and is clutched on in other regions. Further, the variable pulley 115 and the drive side variable pulley combined therewith are basically known as a centrifugal pulley, and by the combination thereof,
As shown in FIG. 3, the characteristics such that the rotation speed of the supercharger is gradually saturated on the high rotation side with respect to the engine rotation speed, that is, the boost pressure does not rise so much in the high rotation range of the engine. Trying to get. Therefore, first, in the low rotation / low load region of the engine, the supercharging is stopped because the electromagnetic clutch 114 is cut, and in other regions, the high rotation side is ensured while ensuring a sufficient intake amount on the low rotation side. In this case, control is performed to suppress an excessive rise in supercharging pressure, so supercharging in a low load region is possible without relying on the efficient and thermal problematic means of suppressing supercharging by intake relief. Can be stopped or suppressed. Further, the auxiliary throttle valve 109 adjusts the amount of air entering the supercharger 105, thereby controlling the supercharging pressure for the load. Therefore, this electromagnetic clutch 114, variable pulley 115 and auxiliary throttle valve 1
By combining the three combinations of 09, it is possible to effectively stop or suppress supercharging in the low load range and effectively realize supercharging control according to the engine speed and load in other operating regions. In the low load range, the bypass valve 113 is opened by the intake negative pressure, and natural intake is performed through the bypass passage 108.

FIG. 4 is a schematic front view showing the entire structure of the engine according to this embodiment, FIG. 5 is a detailed view of the main parts thereof, FIG. 6 is a plan view of the intake system of this embodiment, and FIG. 7 is the same. It is a principal part side view of an intake system.

This engine 101 is a V-type 6 cylinder, and the three cylinders in each of the left and right banks are arranged offset from each other by a predetermined amount. The intake side cam shafts 120 and 121 are arranged inside and the exhaust side cams 122 and 123 are arranged outside the cylinder heads 118 and 119 of the respective banks. Pulleys 124, 125 are attached to the front end portions of the outer exhaust side camshafts 122, 123.
The pulleys 124, 125 are conductively connected to the crankshaft side pulley 127 via the timing belt 126. The tension and wrapping angle of the timing belt 126 are configured to be adjusted by the pair of idler pulleys 128 and 129 on the upper side and the pair of tensioner pulleys 130 and 131 on the lower side. In addition, the intake side cam shaft 118,
119 is drivingly connected to the exhaust side cam shafts 122, 123 of each bank by a pair of gears 132, 133; 134, 135.

Thus, only the outer exhaust side cam shaft is directly driven by the timing belt 126, and the timing belt 126 has a pair of idler pulleys 128,
Since it is positioned downward by 129, a space for a supercharger 105 and its drive pulley 115, which will be described later, can be secured on the engine front surface.

In the space between the left and right banks, a Lisholm type turbocharger 105
Are arranged in the longitudinal direction. The drive pulley 1 is attached to the front end of the supercharger 105 via an electromagnetic clutch 114.
15, a belt 137 is stretched between the drive pulley 115 and a large diameter portion of a driven pulley 136 provided on the left side of the front side of the engine 101, and a small diameter portion of the driven pulley 136 and a crankshaft. A belt 139 is also stretched between a large-diameter driving pulley 138 provided on the. The small diameter portion of the driven pulley 136 and the large diameter portion of the driving pulley 138 are variable pulleys using centrifugal weights. The driven pulley 136 side has a larger diameter due to centrifugal force, and the driving pulley 138 side has a smaller diameter due to centrifugal force. As a result, a characteristic is obtained in which the rotation speed of the supercharger 105 is gradually saturated on the high rotation side.

The intake passages in the cylinder heads 118, 119 are provided with combustion chamber recesses 140, 1
It slightly extends inward from the intake ports 102a, 102b opening toward the center of 41, rises immediately above, and opens above cylinder heads 118, 119. Then, connecting pipes 144, 145 are attached to the openings 142, 143 above the cylinder heads 118, 119. The connecting pipes 144 and 145 extend upward inside the V bank and are located on the left and right above the supercharger 105.
It is connected to 46,147. In addition, these connecting pipes 144,145
In the openings 142,143 above the cylinder heads 118,119.
Injector mounting parts 148, 14
9 is formed, and in order to secure a space for disposing the fuel injector 116 between the wall surfaces of the connecting pipes 144, 145 above the injector mounting portions 148, 149 and the supercharger 105, the upper portions of the connecting pipes 144, 145 are located outside the V bank. It is bent. Therefore,
At this portion, the intake passages 104a and 104b are once curved outward and communicate with the surge tank portions 150 and 151 inside the collecting pipes 146 and 147.

The fuel injector 116 is configured such that the intake ports 102a, 102a of the cylinders 118, 119 are immediately upstream of the openings 142, 143 of the cylinder heads 118, 119.
Fuel is injected toward 102b. The fuel discharge pipe 152 that distributes fuel to these fuel injectors 116 is
Each fuel injector 116 is provided so as to go around the space above it.

The supercharger 105 has an inlet portion 1 as shown in FIGS. 6 and 7.
53 is located on the rear side, and the discharge part 154 is arranged so as to open to the upper part of the supercharger 105 and extend to the front side. Supercharger 10
An intercooler 106 is arranged in front of 5. The intercooler 106 is connected to a central inlet portion 155 flange-connected to the discharge portion 154 of the supercharger 105, cooling portions 156 and 157 horizontally extending to the left and right of the inlet portion, and outer ends of the left and right cooling portions 156 and 157. Each of the outlets 158 and 159 is formed by the outlets 158 and 159 at the left and right ends, and the outlets 158 and 159 at the left and right ends extend rearward and inward.
Connected to 6,147 respectively. A suction pipe 160 is connected to the rear inlet portion 153 of the supercharger 105. A throttle body 161 is provided upstream of the suction pipe 160, and its upstream side is connected to an air cleaner (not shown).

The throttle body 107 is provided with the throttle valve 107, while the auxiliary throttle valve 109, which is linked to the throttle valve 107 with play, is provided at the inlet 153 of the supercharger 105. Further, the suction pipe 160 is provided with a supercharger 10
An upward opening 162 is formed immediately after the connection with the valve 5, and a diaphragm-type bypass valve 113 is provided in the opening 162. Then, the opening 162 of the suction pipe 160 and the supercharger
A bypass pipe 163 is provided that connects the discharge portion 154 of 105 via the bypass valve 113.

As shown in FIGS. 5, 6 and 7, the bypass pipe 163 is located above the left and right banks and is located on the left and right collecting pipes 146 and 14.
7 extends substantially horizontally in the longitudinal direction of the engine, there is no waste in space, and the bypass passage formed by the opening 162 and the bypass pipe 163 has a short passage length and the bent portion is bypassed. It is one of the parts where the valve 113 is installed, and it is compact and has a low intake resistance.

Further, the discharge side of the supercharger 105 is connected to the collecting pipes of the left and right banks via the intercooler 106 in the form of independent long intake passages on the left and right sides, so that the resonance effect is large and the torque is particularly high on the low speed side. The characteristics are good. Moreover,
Although it has such a long intake passage, it has a compact piping structure as a whole.

The present invention can be implemented in various other modes and can be applied to engines other than the V-type.

(Effects of the Invention) Since the present invention is configured as described above, the bypass pipe of the mechanical supercharger is shortened to make the intake system compact, and the increase in intake resistance is suppressed to reduce drive loss. It is possible to secure the filling amount at the time of non-supercharging.

[Brief description of drawings]

FIG. 1 is a schematic view of an engine supercharging system according to an embodiment of the present invention, FIGS. 2 and 3 are characteristic diagrams of the engine supercharging system, and FIG. 4 is a schematic front view of an engine according to the embodiment. 5 and 5 are detailed views of the same, FIG. 6 is a plan view of the same, and FIG.
The figure is a side view of the main part. 101: engine, 105: mechanical supercharger, 106: intercooler, 113: bypass valve, 15: discharge part, 160: suction pipe, 163: bypass pipe.

Claims (1)

[Claims] 1. A Rishorum-type supercharger having an inlet portion axially opening at one end portion in the rotor axial direction and a discharge portion radially opening in the rotor radial direction at the other end portion side in the rotor axial direction. In the upper part of the above, the inlet part is opened rearward and the discharge part is opened upward, the discharge part is extended upward, and the upper part thereof is bent laterally from the middle to be connected to the intercooler. The suction pipe downstream of the air cleaner is connected to the inlet of the feeder to extend the suction pipe rearward in the axial direction of the rotor, and the portion extending above the discharge portion of the supercharger and the suction pipe rearward of the supercharger. An intake system structure for an engine with a mechanical supercharger, characterized in that a bypass pipe is provided so as to connect a portion extending in the rotor axial direction in a substantially L shape.