JPS6128716A - Internal-combustion engine with supercharger - Google Patents

Abstract

PURPOSE:To obtain an internal-combustion engine with an excellent response further with excellent fuel consumption, by controlling a supercharge condition in accordance with the operating speed of a throttle valve and relatively starting a supercharge from a low loaded side of the engine when it is accelerated while spreading a no-supercharge region of the engine when it is driven in steady operation. CONSTITUTION:An engine, when it is in idle operation, is driven in no-supercharge operation by fully opening a bypass flow control valve 11. Under an accelerative condition when a throttle valve is opened by depressing an accelerator from its idle position, the bypass flow control valve 11 is fully closed in the early timing as shown by a curve (a) in the drawing. Under a steady running condition, the engine changes from a supercharge condition to a no-supercharge condition by slowly opening the control valve 11 as shown by a curve (b) in the drawing. The engine, when it is rapidly decelerated from a high loaded condition, rapidly closes the throttle valve 6 at a position of the control valve 11 that it is placed as shown by a curve (c) in the drawing.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a supercharged internal combustion engine.

Conventional technology Superchargers using roots pumps, vane pumps, etc. are known. Since such a supercharger is connected to the engine output shaft and driven, fuel efficiency deteriorates when the engine is lightly loaded and does not require supercharging. Such inconveniences have been solved by the invention described in Japanese Patent Application Laid-Open No. 56-167817. According to this, an electromagnetic flanch is installed in the turbocharger, a bypass passage is formed to bypass the turbocharger, and a bypass valve is placed there that operates in response to the engine load. By disengaging the electromagnetic clutch and opening the bypass valve, there is a slight time difference between the activation of the electromagnetic clutch and the bypass valve, thereby alleviating the important shock of the electromagnetic flanch.'' Problems that the invention aims to solve: Where I did it! In this technology, an electromagnetic clutch is opened and closed under almost constant load conditions (manifold negative pressure, throttle opening, etc.). Therefore, if you set the supercharging region to a relatively high load side, the response will be delayed when you want to accelerate from a light to medium load region. If this setting is made, fuel efficiency will deteriorate because supercharging will be performed frequently even during normal steady driving (for example, city driving) that does not originally require supercharging. Specifically, it is an object of the present invention to obtain a configuration in which supercharging is started from a relatively low load side during acceleration, and supercharging is performed in a high load region during steady state.

Means for Solving the Problems In the internal combustion engine with a supercharger according to the present invention, a control valve is disposed in a bypass intake passage formed by bypassing the supercharger, and a control device for the control valve controls the operation of the throttle valve. The invention is characterized in that it includes means for determining the operating speed of the control valve based on the speed.

The operating state can be determined by the operating speed of the throttle valve, and when the operating speed of the throttle valve is high, it is determined that acceleration or deceleration is occurring and supercharging is started or stopped early. When the throttle valve operates slowly, it is determined that the vehicle is running at a steady state and gradually switches toward supercharging or "no supercharging."Supercharging is performed by closing the bypass control valve, and no supercharging is performed by closing the bypass control valve. Even if the turbocharger continues to rotate, the load on the turbocharger is relieved by relief into the bypass passage.

This reduces fuel consumption and improves fuel efficiency without supercharging. Embodiment In FIG. 1, a well-known intake passage 2 and an exhaust passage 3 are connected to an engine body 1, and the upstream end of the intake passage 2 extends to an air cleaner 4 by means of a vibrator or the like. An air flow meter 5, a throttle valve 6, and a supercharger 7 are installed in the intake passage 2 in this order.
, a fuel injection valve 8 is arranged. The air flow meter 5 is of a known type, and its output signal is sent to an electronic control unit 9. Further, a throttle body sensor 10 for detecting the position of the throttle valve 6 is also known, and its output signal is also sent to the electronic control device 9. Although not shown in FIG. 1, output signals from a crank sensor that detects the position of the crankshaft, a cooling water temperature sensor for the engine, etc. are also sent to the electronic control unit 9, and the electronic control bag W19 is connected to the fuel injection valve 8.
And a control signal is sent to a bypass flow control valve 11, which will be described later. 12 is a battery.

Although the supercharger 7 is shown in FIG. 1 as using a roots pump, other types of pumps such as vane pumps can be used. A pulley 14 is attached to the shaft supporting the rotor 13 of the supercharger 7, and this pulley 14 is connected by a belt or chain 15 to a crank pulley 16 attached to the crankshaft of the engine. is driven by a crankshaft. A bypass intake passage 17 is formed by bypassing the supercharger 7, and its upstream side communicates with the main intake passage 2 between the throttle valve 6 and the supercharger 7, and its downstream side communicates with the supercharger 7. The main intake passage 2 is communicated between the fuel injection valve 8 (a surge tank, not shown, upstream of the fuel injection valve 8).

A bypass flow control valve 11 that can change the area of the passage is arranged in the bypass intake passage 17.

When the bypass flow control valve 11 is fully open, the engine body 1
It will be seen that the amount of air supplied to the engine is supercharged by the supercharger 7 which is rotated relative to the engine. When the bypass flow control valve 11 is slightly opened from fully closed, a portion of the air supercharged by the supercharger 7 escapes from the bypass intake passage 17 depending on the degree of opening, and is therefore supplied to the engine. The amount of air is determined from the amount of supercharged air into the bypass intake passage 1.
The amount is obtained by subtracting the amount of air that escaped through 7. When the bypass flow control valve 11 becomes fully open (or opens more than a predetermined opening degree), the amount of escape from the bypass intake passage 17 increases, and the pressure on the downstream side of the supercharger 7 no longer reaches the pressure on the upstream side (close to atmospheric pressure). ) becomes pressure. Thus, in this case, even if the supercharger 7 continues to rotate, the amount of air taken into the engine is equivalent to that without supercharging when there is no supercharger. Moreover, in this case, even if the supercharger 7 continues to rotate, no load is applied to the supercharger 7, so the power loss of the engine for driving the supercharger 7 becomes extremely small, which is advantageous in terms of fuel efficiency.

From the above description, it can be seen that the bypass flow control valve 11 controls whether the engine is in a supercharging state, a non-supercharging state, or a transition state between these two states.

Further, the function of the bypass intake passage 17 according to the present invention is different from the function of the bypass disclosed in the above-mentioned Japanese Patent Application Laid-open No. 167817/1983.

Next, the configuration and operation of the control device 9 will be explained with reference to FIGS. 2 and 3. As shown in FIG.
consists of a known digital computer, including a central processing unit (CPU) 20 equipped with a clock, a read-only memory (ROM) 21, and a random access memory (
RAM) 22, and signals from various sensors can be input, for example, an air flow meter 5.
The signal from the throttle position sensor 10 is input directly to the CPII together with the signal from the cluster angle sensor 23, and the signal from the throttle position sensor 10 is input via the A/D converter 24. Control signals to the bypass flow control valve (EACV) 11 and the fuel injection valve 8 are provided via the output interface 25. FIG. 3 shows a control flowchart for the bypass flow control valve 11. This routine is activated at predetermined short intervals.

In FIG. 3, the throttle opening (
TA). Next, in step 102, it is determined whether the throttle opening degree TA is smaller than a predetermined first set value X. For example, as shown in FIG. 4, the first set value X can be set to around 10 degrees of throttle opening, and the second set value Y can be set to around 70'. Throttle opening TA is the first set value X
If it is smaller, the process proceeds to step 111 and the bypass flow rate control 11 is maintained fully open. If the determination in step 102L is NO, then in step 103 the second set value Y is further compared. If TA is larger than Y, it is determined that the load is in a high load region, and the bypass flow control valve E is activated in step 112.
Keep ACVII fully closed. If YES in step 103, the process proceeds to step 104, where it is compared with the previously stored throttle opening TAOLD and TA≧TA is determined.
OLD indicates that the throttle valve 6 is being operated in the acceleration direction, and TA 7 indicates that the throttle valve 6 is being operated in the direction of acceleration, and TA OLD indicates that the vehicle is decelerating. If the vehicle is accelerating, the program advances to step 105; if the vehicle is decelerating, the program advances to step 108. and,
Since this control routine is started at predetermined short intervals,
ΔTA=TA−TAOLD or ΔTA′=TAO
The opening/closing speed of the throttle valve 6 can be known from L and D-TA.

The ROM 21 of the control unit W9 stores the bypass flow rate control valve 11 corresponding to the throttle opening/closing speed in a map format as shown in FIG.
The opening/closing speed of the EACV is stored, and the closing speed (S+) or opening speed (S2) of the EACV can be determined from this map in step 106 or 109.
7 or 110, a control signal is generated to drive the bypass flow control valve 11 at the respective determined speeds. In this embodiment, the map shown in FIG. 5 serves as a means for determining the operating speed of the flow control valve 11.

Bypass failure control valve (EA) according to the above flowchart.
If you follow the movement of CV) 11, it will look like Figure 4, for example. Bypass flow control valve 11 when the engine is idle
is fully opened and non-supercharging operation is performed. When you step on the accelerator from idle and open the throttle valve, it is in an acceleration state, and at this time, the bypass flow control valve 1 begins to close at the first set value X, as can be seen from map 1 in Figure 5. Since the closing speed of the bypass flow control valve 11 is also fast, as shown by the arrow (al), it is fully closed at a faster time than the throttle opening, improving the response of supercharging. Even after acceleration is finished, high-speed, high-load operation continues When this continues, the bypass flow rate IIJ111I valve 11 is kept fully open.When the acceleration is finished and the vehicle starts steady driving such as city driving, the throttle valve 6 is generally returned to a slow opening. In this case, arrow 0)
The flow control valve 11 slowly opens as shown by l.
Therefore, there is a slow transition from the supercharged state to the non-supercharged state. Therefore, since there is no sudden torque change at this time, drivability is not impaired. In a steady running state, the accelerator operation is usually small and the operating speed is slow, so the flow control valve 11 is maintained at a position close to fully open. When accelerating from the steady running state, the flow rate control valve 11 closes rapidly from the position where the throttle valve 6 was at that time, making it possible to perform acceleration with good response. Furthermore, when decelerating suddenly from a high load state, the flow rate control valve 1i closes rapidly near the position where the throttle valve 6 was at that time, as shown by arrow (C), so that responsive deceleration performance can be obtained. become.

Effects of the Invention As explained above, according to the present invention, the supercharging conditions can be controlled according to the operating speed of the throttle valve, and during acceleration, supercharging is started from the relatively low load side, and the Since the non-supercharging region can sometimes be expanded, an internal combustion engine with excellent response and excellent fuel efficiency can be obtained.

[Brief explanation of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention, FIG. 2 is a configuration diagram of the control device in FIG. 1, FIG. 3 is a control flowchart of the control device in FIG. FIG. 5, which is a diagram explaining the operation, is a map that defines the opening and closing speed of the flow rate control valve. 1... Engine body, 2... Intake passage, 6...
... Throttle valve, 7... Supercharger, 9... Control device, 10... Throttle position sensor, 11... Flow rate control valve, 17... Bypass intake passage. 4th page grip throttle opening 5th ■

Claims (1)

[Claims] A control valve is provided in a bypass intake passage formed by bypassing the supercharger, and a control device for the control valve determines the operating speed of the control valve based on the operating speed of the throttle valve. A supercharged internal combustion engine characterized by comprising means for.