JPH0526923B2 - - Google Patents

Description

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

BACKGROUND ART 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. 167817/1983. According to this, in addition to installing an electromagnetic clutch in the supercharger,
A bypass passage is formed to bypass the supercharger, and a bypass valve that operates according to the engine load is placed there. In areas where supercharging is not performed, the electromagnetic clutch is disengaged and the bypass is opened, and the electromagnetic clutch and bypass valve are closed. The shock of turning on and off the electromagnetic clutch is also alleviated by providing a slight time difference in operation.

Problems to be Solved by the Invention In the prior art described above, the electromagnetic clutch is opened and closed under substantially constant load conditions (manifold negative pressure, throttle opening, etc.). Therefore, if you set the supercharging range to a relatively high load side, the response will be delayed when you want to accelerate from a light to medium load range, and conversely, if you set the supercharging range to a relatively low load side, the response will be delayed. If set to , the fuel consumption will deteriorate because supercharging will be performed frequently even during normal steady driving (for example, city driving, etc.) where supercharging is not actually required. The present invention solves the above problems,
By changing the speed at which the bypass control valve is fully closed according to the driver's acceleration request, supercharging can be started from a relatively low load side during acceleration, and supercharging can be performed in a high load area during steady state conditions. The purpose is to provide a motorized internal combustion engine.

Means for Solving the Problems According to the present invention, there is provided a supercharger, a bypass intake passage that bypasses the supercharger and connects an intake passage on an inlet side and a discharge side of the supercharger, and the bypass intake passage. In a supercharged internal combustion engine, which is equipped with a control valve disposed in the engine intake passage, and controls supercharging pressure by opening and closing the control valve according to the engine load, the valve opening speed of the throttle valve disposed in the engine intake passage is controlled. There is provided a supercharged internal combustion engine characterized in that it is provided with means for detecting and means for determining the speed at which the control valve is fully closed based on the detected throttle valve opening speed.

Operation The operating state can be determined by the operating speed of the throttle valve, and when the operating speed of the throttle valve is fast, 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 the vehicle is gradually switched toward supercharging or non-supercharging. Supercharging is performed by closing the bypass control valve, and non-supercharging is performed by opening the bypass control valve. Even if the supercharger continues to rotate, the load on the supercharger is reduced by relieving the supercharger to the bypass passage, improving fuel efficiency when not supercharging. Additionally, the speed at which the bypass control valve is fully closed during acceleration is controlled according to the opening speed of the throttle valve.
When the driver requests sudden acceleration (that is, when the opening speed of the throttle valve is high), the bypass control valve is fully closed in a short time regardless of the opening degree of the throttle valve, reducing the rate of increase in boost pressure. is faster, and the supercharging pressure obtained is also greater.

Embodiment In FIG. 1, a well-known intake passage 2 and an exhaust passage 3 are connected to an engine body 1, and the intake passage 2 has an upstream end extending to an air cleaner 4 through a pipe or the like. An air flow meter 5, a throttle valve 6, a supercharger 7, and a fuel injection valve 8 are arranged in this order in the intake passage 2. 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 position sensor 10 for detecting the position of the throttle valve 6 is also known.
The output signal is also sent to the electronic control unit 9. 1st
Although not shown in the figure, 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 device 9, and the electronic control device 9 is connected to the fuel injection valve 8 and will be described later. A control signal is sent to the bypass flow control valve 11. 12
is a complete failure.

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 that supports the rotor 13 of the supercharger 7, and this pulley 14 is attached to a belt or chain 1.
5 is connected to a crank pulley 16 mounted on the engine crankshaft, and thus the supercharger 7 is driven by the engine crankshaft. A bypass intake passage 17 is formed by bypassing this 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 closed,
It can be seen that the amount of air supplied to the engine body 1 is supercharged by the supercharger 7 which rotates 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 is fully opened (or above 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 is no longer as high as the pressure on the upstream side (close to atmospheric pressure). ) Pressure.Thus, in this case, even if the supercharger 7 continues to rotate, the amount of air taken into the engine is equivalent to the amount of air 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 explanation, , bypass flow control valve 11
It can be seen that whether the engine is in a supercharged state, a non-supercharged state, or a transition state between these two states is controlled by the following. Further, the function of the bypass intake passage 17 according to the present invention is described in the above-mentioned Japanese Patent Application Laid-Open No.
This is different from the bypass action of Publication No. 167817.

Next, the configuration and operation of the control device 9 will be explained with reference to FIGS. 2 and 3. As shown in FIG. 2, the control device 9 consists of a known digital computer, including a central processing unit (CPU) 20 equipped with a clock, and a read-only memory (ROM) 2.
1. It is equipped with a random access memory (RAM) 22, into which signals from various sensors can be input. For example, the signal from the air flow meter 5 is input directly to the CPU together with the signal from the crank angle sensor 23. , a signal from the throttle position sensor 10 is inputted via an A/D converter 24. Bypass flow control valve (EACV) 1
1 and the fuel injection valve 8 are provided via an 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) is acquired in step 101. Next, in step 102, it is determined whether the throttle opening 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 degrees.
If the throttle opening TA is smaller than the first set value X, proceed to step 111 and bypass flow control 11.
keep it fully open. If the determination in step 102 is NO, then in step 103 a comparison is made with a second set value Y. If TA is larger than Y, it is determined that the system is in a high load region, and in step 112, the bypass flow control valve EACV11 is maintained fully closed. step
If YES in step 103, the process proceeds to step 104, where it is compared with the previously stored throttle opening TAOLD, and if TA≧TAOLD, it indicates that the throttle valve 6 is being operated in the acceleration direction, and TA<
If it is TAOLD, it indicates that the vehicle is decelerating. If the vehicle is accelerating, proceed to step 105; if decelerating, proceed to step 108. Since this control routine is started at predetermined short intervals,
ΔTA=TA−TAOLD or ΔTA′=TAOLD−
The opening/closing speed of the throttle valve 6 can be determined by TA. The ROM 21 of the control device 9 has a fifth
The opening/closing speed of the bypass flow control valve 11 relative to the throttle opening/closing speed is stored in a map shape as shown in the figure, and the closing speed S ₁ or opening speed S ₂ of the EACV can be determined from this map in step 106 or 109. , a control signal is generated to drive the bypass flow control valve 11 at the respective determined speeds in step 107 or 110. In this embodiment, the map shown in FIG. 5 serves as a means for determining the operating speed of the flow control valve 11.

If the movement of the bypass flow control valve (EACV) 11 is followed according to the above flowchart, the result will be as shown in FIG. 4, for example. When the engine is idling, the bypass flow control valve 11 is fully open and non-supercharging operation is performed. When you step on the accelerator from idle and open the throttle valve, you are in an accelerating state, and at this time the bypass flow control valve 11 begins to close at the first set value Since the closing speed of the flow rate control valve 11 is also fast, it becomes fully closed earlier than the throttle opening as shown by arrow a, and as can be seen from map 1 in Fig. 5, the closing speed of the bypass control valve 11 is fast. The faster the closing speed of the throttle valve is, the faster the closing speed of the throttle valve becomes. Therefore, during sudden acceleration, the bypass control valve is fully closed earlier than during slow acceleration, resulting in better acceleration response. Bypass flow control valve 1 is activated when high-speed, high-load operation continues even after acceleration has finished.
1 is maintained fully closed. When acceleration ends and the transition to steady driving, such as city driving, the throttle valve 6 is generally slowly returned to a certain opening degree. The engine slowly opens, and the supercharged state slowly shifts from the supercharged state to the non-supercharged state. Therefore, since there is no sudden torque fluctuation 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 control valve 11 closes rapidly near the position where the throttle valve 6 was at that time, as shown by arrow c, resulting in a highly responsive deceleration performance. .

Effects of the Invention As described above, according to the present invention, the opening speed of the throttle valve is detected and the fully closing speed of the throttle valve is changed according to this valve opening speed. By starting supercharging from the low load side, the non-supercharging region can be expanded during steady state. Furthermore, during acceleration, the rate and magnitude of increase in supercharging pressure are controlled according to the degree of the driver's acceleration request, so it is possible to improve fuel efficiency and acceleration response.

[Brief explanation of the drawing]

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, and FIG.
4 is a diagram explaining the operation of the flow control valve, and FIG. 5 is a map defining the opening/closing speed of the flow control valve. DESCRIPTION OF SYMBOLS 1... Engine body, 2... Intake passage, 6... Throttle valve, 7... Supercharger, 9... Control device, 10
...Throttle position sensor, 11...Flow control valve, 17...Bypass intake passage.

Claims (1)

[Claims] 1 A turbocharger, a bypass intake passage that bypasses the turbocharger and connects an intake passage on the intake side of the turbocharger and a discharge side, and a control valve disposed in the bypass intake passage, the control valve A means for detecting the opening speed of a throttle valve disposed in an engine intake passage, and a means for detecting the detected throttle valve opening speed in an internal combustion engine with a supercharger that controls boost pressure by opening and closing the throttle valve according to the engine load. 1. A supercharged internal combustion engine, comprising means for determining a speed at which the control valve fully closes based on the following.