JPS6234928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-stage supercharged engine for two-wheeled motor vehicles, and provides a layout that enables two-stage supercharging without increasing the distance between front and rear wheels (wheelbase) or overall width. , aimed at improving output.

Small compressors with compressor impeller diameters of around 40 mm have low adiabatic efficiency at high pressure ratios (about 2), and the overall supercharger efficiency is also extremely low, making it difficult for small supercharged engines to generate high torque over the entire rotation range. It is. Therefore, as a countermeasure to this problem, it is possible to introduce a two-stage supercharging system to motorcycles.
In this case, the benefits include improving the adiabatic efficiency of the compressor at high pressure ratios, improving the output response to load fluctuations, expanding the flow range, and improving low-speed torque by controlling the high-pressure turbine's exhaust bypass. Because there is little room, it is difficult to create a compact layout with two superchargers, an intercooler, an aftercooler, etc.

The present invention opens an exhaust port upward from between the front exhaust cam and the rear intake cam of a double overhead cam (DOHC) in-line engine for motorcycles, and connects the exhaust port directly above the engine via the exhaust manifold. By connecting to the high-pressure turbine inlet of the high-pressure supercharger, the layout can be made more compact.The in-line double overhead cam engine is placed horizontally at right angles to the direction of travel, with the exhaust cam at the front and the intake cam at the front. The exhaust port is opened upward from between the intake and exhaust cams, and the high-pressure supercharger is placed on one side directly above the engine, the intercooler is placed on the other side, and the low-pressure supercharger is placed on the front side. It is characterized by having an aftercooler arranged on the rear side, and the exhaust port of each cylinder is connected to the high-pressure turbine inlet of the high-pressure supercharger via an exhaust manifold.This will be explained with reference to the drawings as follows.

FIG. 1 is a vertical left side view showing a three-cylinder in-line double overhead cam engine 1 according to the present invention in a cross section perpendicular to the crankshaft. ing. An exhaust valve 4 and an intake valve 5 are supported for each cylinder in a cylinder head 3 that is fastened to the upper end surface of the cylinder block 2 with a plurality of bolts, and the exhaust valve 4 partitions a combustion chamber 6 and an exhaust port 7. and intake valve 5
partitions the combustion chamber 6 and the intake port 8. 9 is a piston, and 10 is a connecting rod. The upper ends of the exhaust valve 4 and the intake valve 5 are in elastic contact with the exhaust cam 13 and the intake cam 14 via tappets 11 and 12 due to the elasticity of the valve springs. 15 and 16 are cam covers.

Whereas the conventional exhaust port 7 extends forward from the exhaust valve 4 (to the left in Figure 1), the exhaust port 7 extends upward within the cylinder head 3 between the exhaust cam 13 and the intake cam 14, and extends upward from the exhaust cam 13 and the intake cam 14. The exhaust manifold 18 is connected to the exhaust manifold 18. In the illustrated embodiment, the exhaust manifold 18 has a lower end connected to each exhaust port 7 of the three cylinders, and an upper end connected to the high pressure supercharger _T1.
The high pressure turbine 20 is connected to the inlet 21 of the high pressure turbine 20 .
The exhaust gas outlet 22 of the high-pressure turbine 20 is connected to the inlet 24 of the low-pressure turbine 23 of the low-pressure supercharger _T2 ,
As shown in FIG. 3, the exhaust gas outlet 25 of the low pressure turbine 23 is exposed to the atmosphere via a downward exhaust pipe 26 and a rearward muffler 27.

A turbine wheel (not shown) in the high-pressure turbine 20 is a high-pressure compressor 29 in the high-pressure supercharger _T1 .
The turbine wheel (not shown) in the low-pressure turbine 23 is directly connected to the compressor wheel (not shown) in the low-pressure supercharger _T2 . (not shown). Air inlet 31 of low pressure compressor 30
(Fig. 2) communicates with the atmosphere via an air flow meter and an air filter on its upstream side. The pressurized air outlet 32 of the low pressure compressor 30 is connected to the inlet 34 of the high pressure compressor 29 via an intercooler 33.
The pressurized air outlet 35 of the high pressure compressor 29 is connected to the aftercooler and equalizer tube 3.
7, the intake pipe 38 is connected to the intake port 8 of each cylinder. In FIG. 2, 40 is a front wheel, 41 is a rear wheel, thin arrows indicate the flow of exhaust gas, and thick arrows indicate the flow of intake air. Further, in FIG. 1, 42 is a throttle valve.

As is clear from FIGS. 1 and 2, in the present invention, the high-pressure supercharger _T1 is located on the left side (FIG. 2) of the space directly above the cylinder head 3 of the engine 1, and the intercooler T1 is located on the right side of the space. 33, a low-pressure supercharger _T2 is placed immediately before them, and an aftercooler 36 is placed immediately after. When such a supercharged engine is installed in a motorcycle, the left side layout is as shown in Figure 3.
High and low pressure superchargers T ₁ , T ₂ and aftercooler 36
occupies the position where the fuel tank was previously located,
A cover with approximately the same external shape as the fuel tank (not shown)
covered by. 45 is a handle, 46 is a front fork, and 47 is a swing arm.

Next, the operation will be explained. In Fig. 1, the combustion chamber 6
Exhaust gas _generated in After entering the low pressure turbine 23 of the supercharger T ₂ and driving the internal turbine wheel, it is discharged from the outlet 25 through the exhaust pipe 26 (FIG. 3) and the muffler 27 into the atmosphere. On the other hand, in FIG. 2, the air after passing through the air filter and air flow meter enters the low pressure compressor 30 of the low pressure supercharger _T2 from the inlet 31.
After being pressurized by the internal impeller, intercooler 3
3 and after being cooled there, the high pressure supercharger T ₁
The high-pressure compressor 29 is further pressurized by the internal impeller, and the aftercooler 3 is sent from the outlet 35.
6, and after being cooled there, the equalizer tube 37, intake pipe 38, intake port 8, intake valve 5
The fuel is then supplied to the combustion chamber 6 of each cylinder. Heat from the high-pressure turbine 20 and low-pressure turbine 23 is prevented from being radiated by a heat insulating plate 17 (indicated by thick broken lines in FIGS. 1 and 2) coated on their outer surfaces, and the intercooler 33 and engine exhaust system A heat insulating plate 19 (FIG. 2) between the intercooler 33 and the intercooler 33 prevents heat from the engine exhaust system from being transferred to the intercooler 33.

As explained above, in the present invention, the in-line double overhead cam engine 1 is arranged horizontally at right angles to the traveling direction (arrow F), with the exhaust cam 13 at the front and the intake cam 14 at the rear. The exhaust port 7 is opened upward from between the cams 14 and 13, and the high-pressure supercharger _T1 is placed on one side of the left and right directly above the engine, the intercooler 33 is placed on the other side, the low-pressure supercharger T2 is placed on the front side, and the low-pressure supercharger _T2 is placed on the rear side. Aftercoolers 36 are placed on each side, and the exhaust port 7 of each cylinder is connected to the high-pressure turbine inlet 21 of the first stage supercharger T ₁ via the exhaust manifold 18, making the layout more compact and making it easier for motorcycles. It becomes possible to adopt a two-stage supercharging system. Therefore, the bypass valve 48,4
By operating 9 appropriately, controlling the high-pressure and low-pressure turbine rotation speeds, and operating the high-pressure and low-pressure compressors within the optimum operating range, it is possible to obtain high torque with a small engine from low speed to high speed. becomes. In addition, since a relatively high air supply pressure of about 1.5 to 2 kg/cm ² in total can be obtained at a lower temperature than in the case of a single stage, it is also possible to increase the output limit due to abnormal combustion of the supercharged gasoline engine. If the exhaust port 7 is placed in front of the exhaust valve 4, the first stage supercharger _T1 will protrude significantly in front of the engine, increasing the wheelbase and making it difficult to put it into practice. Since it opens upward between the cams 14 and 13, the high-pressure supercharger T ₁ occupies the position directly above the engine, and the low-pressure supercharger T ₂ in front of it is placed above the exhaust cam cover 15 to prevent it from protruding forward. It can be held and placed in small quantities, making the whole thing compact.

[Brief explanation of the drawing]

FIG. 1 is a vertical left side view of a two-stage supercharged engine according to the present invention, FIG. 2 is a plan view, and FIG. 3 is a left side view showing a state in which the two-stage supercharged engine is mounted on a motorcycle. 1...Engine, 7...Exhaust port, 11...Exhaust cam, 12...Intake cam, 18...Exhaust manifold, 21...High pressure turbine inlet, 33...Intercooler, 36...Aftercooler, _T1 ...High pressure supercharger, _T2 ...Low pressure supercharger.

Claims (1)

[Claims] 1. An in-line double overhead cam engine is placed horizontally at right angles to the direction of travel, with the exhaust cam at the front and the intake cam at the rear.The exhaust port is opened upward from between the intake and exhaust cams, and is placed directly above the engine. A high-pressure supercharger is placed on one side of the left and right side, an intercooler is placed on the other side, a low-pressure supercharger is placed on the front side, and an aftercooler is placed on the rear side.The exhaust port of each cylinder is connected to the first stage via an exhaust manifold. A two-stage supercharged engine for a motorcycle, characterized in that it is connected to a high-pressure turbine inlet of a supercharger.