JPS6363730B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a supercharging device for an intake system of an internal combustion engine.

[Conventional technology and its problems]

It is widely known that supercharging is used as a means to increase output and improve fuel efficiency in internal combustion engines. Three types of "supercharging" are known.
Exhaust turbocharging uses the energy contained in the exhaust gas from the internal combustion engine to drive the turbocharger, so although it is extremely effective in the high-speed rotation range where the energy of the exhaust gas is large, it is slower than this. Not only is there little improvement in output in the rotation range, but the response at the beginning of acceleration of the internal combustion engine is poor, and
During deceleration, there is a risk of overcharging due to the inertial rotation of the turbocharger. In contrast, institutional supercharging
Since a mechanical supercharger such as a Roots blower is rotationally driven by an internal combustion engine, it is effective and responsive in a lower rotation range than the exhaust turbo supercharging, and there is no supercharging during deceleration, etc. On the other hand, in order to secure a predetermined amount of intake air in the high-speed range of the internal combustion engine, the capacity of the mechanical supercharger must be increased, which means that the mechanical supercharger becomes significantly larger. Not only that, but there is a problem with the durability of mechanical superchargers in the high rotation range, and moreover, the power loss required to drive the mechanical supercharger increases approximately squarely with the rotation speed. Therefore, the output improvement in the high rotation range is low. In addition, inertial supercharging involves installing a surge tank in the intake system for the cylinder.
The length of the intake passage from the surge tank to the combustion chamber of the cylinder is set so that the amount of intake air is approximately at its maximum in a specific rotation range where the internal combustion engine is frequently used. Although the structure is relatively simple and the installation space is not significantly increased, the effect of inertial supercharging cannot be obtained in rotation ranges other than the above-mentioned specific rotation range.

Therefore, in Japanese Patent Application No. 56-69221 (Japanese Unexamined Patent Publication No. 57-183523), which we previously applied for,
The rotation speed of the internal combustion engine is divided into a rotation range of approximately medium speed or lower and a rotation range of approximately medium speed or higher, and in the rotation range of approximately medium speed or lower, the mechanical supercharger is driven by the internal combustion engine. By doing so, mechanical supercharging is performed, and in the rotation range above approximately medium speed, the drive of the mechanical supercharger is stopped and inertial supercharging is performed. The shortcomings are compensated for by inertia supercharging, and the incompatibility of inertia supercharging over a wide rotation range is compensated for by mechanical supercharging, and both combine to enable effective supercharging over the entire rotation range of the internal combustion engine. I suggested what I did.

However, a certain amount of power is required to drive a mechanical supercharger, and the ratio of the power required to drive it to the output of the internal combustion engine increases as the load on the internal combustion engine becomes lower. However, if the intake air amount or fuel injection amount per crankshaft rotation for the internal combustion engine is reduced, the increase value that can improve the output of the internal combustion engine by driving the mechanical supercharger, and the mechanical supercharger The amount of power required to drive the mechanical supercharger becomes almost balanced, making it impossible for the mechanical supercharger to exhibit its effectiveness.In particular, the intake air amount or fuel injection amount per crankshaft rotation may Therefore, if the increase value that can improve the output of the internal combustion engine and the power value required to drive the mechanical supercharger become smaller than the value at which it is in equilibrium, the power required to drive the mechanical supercharger becomes greater. , fuel consumption in the internal combustion engine tends to increase accordingly.

In addition, even when the amount of intake air or fuel injection per revolution of the crankshaft is large, when the engine speed is low near the idle link, for example when going uphill or at the beginning of sudden acceleration from idling. At first, the mechanical supercharger operates slowly, and driving the mechanical supercharger in this state requires a considerable amount of power to drive the mechanical supercharger, which reduces the power used for driving. is consumed by the drive of the mechanical supercharger, which not only reduces drivability but also increases fuel consumption as described above.

The present invention aims to solve this problem.

[Means for solving problems]

In order to achieve this object, the present invention provides a surge tank communicating with an air cleaner in the intake system for a cylinder in an internal combustion engine, and a mechanical supercharger that is rotationally driven by the internal combustion engine. The length of the intake passage from the surge tank to the combustion chamber of the cylinder is
While the intake air amount is set to be approximately maximum in the rotation range of approximately medium speed or higher in the internal combustion engine, the power transmission mechanism from the internal combustion engine to the mechanical supercharger is When the rotation speed is other than medium speed rotation, and when the intake air amount or fuel injection amount per crankshaft rotation is smaller than a value that can improve the output of the internal combustion engine by driving the mechanical supercharger. , a configuration is provided in which means is provided for cutting off power transmission to the mechanical supercharger.

〔Example〕

The following describes the drawings in which the embodiments of the present invention are applied to a carburetor type internal combustion engine.
2 respectively indicate displacement type mechanical superchargers such as roots, movable blades, or reciprocating type, and the mechanical supercharger 2
has a relatively small capacity so that a predetermined supercharging can be performed only in a rotation range below approximately medium speed rotation N1 in the internal combustion engine 1, and the belt 4 is connected from the crankshaft 3 etc. in the internal combustion engine 1. It is rotationally driven through a power transmission mechanism such as, and the power transmission mechanism includes a
Means for turning on or off is provided, for example an electromagnetic clutch 5.

Reference numeral 6 indicates a surge tank for inertial supercharging,
The surge tank 6 is connected to an intake port 7 in each cylinder of the internal combustion engine 1 via an independent intake pipe 8, and is located at a point where the intake port 7 in each cylinder opens into the combustion chamber of the cylinder. The intake passage length l from 1 to the opening into the surge tank 6 is set to a length such that the amount of intake air is maximized in a rotation range of approximately medium speed N1 or higher in the internal combustion engine 1. ing.

Reference numeral 9 indicates an air cleaner, and an intake passage 1 connects the air cleaner 9 and the surge tank 6.
0, there is a throttle valve 12 for adjusting intake air on the way.
The air cleaner 9 is connected to the carburetor 11 at the upstream side of the carburetor 11.
A check valve 13 that opens only in the direction of Discharge passages 15 from the mechanical superchargers 2 are connected to each other.

The intake passage 10 is provided with an air flow meter 16 for measuring the amount of intake air immediately downstream of the air cleaner 9, and the internal combustion engine 1 is provided with a rotation sensor 17. The electromagnetic clutch 5 for turning ON and OFF the
A control circuit 18 for controlling this is connected to the control circuit 18, and signals from the air flow meter 16 and rotation sensor 17 are given as inputs to the control circuit 18.

Based on the output signal from the rotation sensor 17, the control circuit 18 operates the electromagnetic clutch 5 when the engine rotation speed is below a low rotation (N0) near idling and when the engine rotation speed is above the approximately medium speed rotation (N1).
The electromagnetic clutch 5 is turned OFF, and the electromagnetic clutch 5 is turned ON only when it is within the range of N0 to N1.

Further, the control circuit 18 receives the output signal from the air flow meter 16 and the rotation sensor 1.
Based on the output signal from 7, a certain value (Q/
Ni) In the following cases, the electromagnetic clutch 5 is turned off regardless of the rotational speed of the internal combustion engine 1.

That is, the control circuit 18 controls the control circuit 18 so that the number of revolutions in the internal combustion engine 1 is within the range of (N0) to (N1) and the amount of intake air per revolution of the crankshaft 3 exceeds a certain value (Q/Ni). The electromagnetic clutch 5 is activated only when the rotational speed of the internal combustion engine 1 is below (N0) and above (N1), and when the amount of intake air per revolution of the crankshaft 3 is a certain value (Q/Ni). ) In the following cases, the electromagnetic clutch 5 is turned off. However, N0<Ni<N1.

In this configuration, the amount of intake air per revolution of the crankshaft 3 is greater than or equal to a certain value (Q/Ni), and the rotational speed of the internal combustion engine 1 is between (N0) and
(N1), the electromagnetic clutch 5 is ON.
Then, the mechanical supercharger 2 is driven, and the intake air from the air cleaner 9 is compressed by the mechanical supercharger 2 and then supplied to the cylinders, so that the internal combustion engine 1
It operates with so-called mechanical supercharging.

When the rotation speed of the internal combustion engine 1 exceeds (N1) and becomes high speed, the electromagnetic clutch 5 is turned off and the power transmission to the mechanical supercharger 2 is cut off, so that the intake air from the air cleaner 9 is , without passing through the mechanical supercharger 2, in other words, bypassing the mechanical supercharger 2 and directly introduced into the surge tank 6. In this case, the length l of the intake passage from the surge tank 6 to the combustion chamber of each cylinder is
Since the amount of intake air is set to be maximum in the rotation range of (N1) or higher, the engine is operated with so-called inertial supercharging in the rotation range of (N1) or higher.

Even if the amount of intake air per revolution of the crankshaft 3 is more than a certain value (Q/Ni),
When the rotation speed of the internal combustion engine 1 becomes less than (N0),
The electromagnetic clutch 5 turns OFF, and the mechanical supercharger 2
Since power transmission to the engine 1 is cut off, the internal combustion engine 1 enters a non-supercharging state, and even if the rotational speed is higher than (N0), the amount of intake air per revolution of the crankshaft 3 is lower than that of the throttle valve 12. When the value falls below the above-mentioned value (Q/Ni) due to closing, etc., the electromagnetic clutch 5 is turned OFF.
As a result, the power transmission to the mechanical supercharger 2 is cut off, so the internal combustion engine enters the non-supercharging state as described above.

In this case, the certain value (Q/
By setting Ni) to a value that can improve the output of the internal combustion engine by driving the mechanical supercharger 2, the rotational speed of the internal combustion engine 1 can be adjusted from (N0) to
Even if it is within the range of (N1), if the amount of intake air per revolution of the crankshaft to the internal combustion engine 1 falls below this certain value (Q/Ni), the power transmission to the mechanical supercharger 2 will be interrupted. This prevents an increase in fuel consumption due to driving the mechanical supercharger 2 with a small amount of intake air per crankshaft revolution. The amount of intake air of
Ni) or higher, when the rotational speed of the internal combustion engine 1 drops below (N0), the power transmission to the mechanical supercharger 2 is cut off, and the power load required for its drive is released. This makes it possible to prevent the disadvantages of driving the mechanical supercharger 2 in a low rotation range, that is, a decrease in drivability and an increase in fuel consumption.

In addition, in the above embodiment, an air flow meter 16 is provided in the intake system of the carburetor internal combustion engine, and a rotation sensor 17 is provided in the internal combustion engine 1.
We have shown a case where the amount of intake air per revolution of the crankshaft is detected using these methods, but in the case of a fuel-injected gasoline engine, the intake system is necessarily equipped with an air flow meter, so this air flow meter is In the case of a diesel engine, it can be applied in the same manner as described above by providing an air flow meter in the intake system.

However, even in the case of a diesel engine that only controls the amount of fuel injection, or a gasoline engine,
In the case of a fuel injection type internal combustion engine that does not directly measure the intake air amount, such as the hot wire type, Karman vortex type, or intake pipe negative pressure type, but estimates the intake air amount and controls the increase/decrease of the fuel injection amount. can be similarly applied by using the amount of fuel injection per revolution of the crankshaft instead of the amount of intake air per revolution of the crankshaft as in the above embodiment.

[Action/effect of the invention]

As described above, the present invention achieves the functions and effects described below by having the configuration described in the claims.

Mechanical superchargers only need to operate in the rotational range of approximately medium speed or lower in internal combustion engines.
The mechanical supercharger does not have a large capacity like when operating in the entire rotation range of an internal combustion engine, and it is possible to reduce power loss when driving the mechanical supercharger in a high rotation range. This can avoid shortening the lifespan of the turbocharger.

This is because the drive of the mechanical supercharger is stopped when the rotational speed of the internal combustion engine becomes low, near idling, or when the amount of intake air or fuel injection per revolution of the crankshaft to the internal combustion engine becomes small. , the disadvantages of rotating the mechanical supercharger in the low rotation range and in the operating range where the intake air amount or fuel injection amount per crankshaft revolution for the internal combustion engine is small, that is, increased fuel consumption, and the driver It is possible to reliably prevent a decrease in integrity.

[Brief explanation of drawings]

The drawings are diagrams showing embodiments of the invention. DESCRIPTION OF SYMBOLS 1... Engine, 2... Mechanical supercharger, 5... Electromagnetic clutch, 6... Surge tank, 10... Intake passage, 16... Air flow meter, 17... Rotation sensor, 18... Control path.

Claims (1)

[Claims] 1 In the intake system for the cylinder in an internal combustion engine,
a surge tank communicating with an air cleaner is provided, a supercharging passage equipped with a mechanical supercharger rotationally driven by the internal combustion engine is connected to the surge tank;
The length of the intake passage from the surge tank to the combustion chamber of the cylinder is set so that the amount of intake air is approximately maximum in a rotation range of approximately medium speed or higher in the internal combustion engine, while the mechanical supercharging from the internal combustion engine is The mechanical supercharger is used in the power transmission mechanism to the engine when the rotational speed of the internal combustion engine is other than low or medium speed rotation, and when the intake air amount or fuel injection amount per crankshaft rotation is A supercharging device for an internal combustion engine, characterized in that means is provided for cutting off power transmission to the mechanical supercharger when the output of the internal combustion engine is smaller than the value that can improve the output of the internal combustion engine by driving the mechanical supercharger.