JPH0417788Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) This invention relates to a throttle valve dart pot device for an internal combustion engine, which is installed to prevent jerky vibrations and shocks when a vehicle decelerates, and is particularly designed to prevent poor deceleration sensation and improve drivability. Regarding the improvement of (Prior Art) As a conventional throttle valve dart pot device for an internal combustion engine, for example, "Nissan Automobile Maintenance Manual"
There are some such as those described in "NAPSL Capretor Specifications". To briefly explain this with reference to FIG. 4, an adjusting screw 2 is screwed into a lever 1 which is fixed to a throttle valve of a fuel supply device (not shown) and is linked to the opening and closing of this throttle valve. When the throttle valve is moved in the closing direction, the tip of the adjusting screw 2 comes into contact with the tip of the plunger 3 and moves the plunger 3 to the right against the force of the spring 6. push it back towards you. The plunger 3 is attached to a diaphragm 5, and the diaphragm 5 and the case 7 form an air chamber 4. Therefore, the movement of the plunger 3 causes the diaphragm 5 to reduce the volume of the air chamber 4. At this time, the flow rate of the air pushed out from the air chamber 4 by the diaphragm 5 is restricted by a variable jet needle 12 provided at the outlet 11, and the air flows out through the air filter 8 to the atmosphere. Thereby, the movement of the plunger 3 is damped, slowing down the speed at which the throttle valve closes from a given TVO. When the throttle valve is then opened, the diaphragm 5 is pushed back to the left by the spring 6, and in order to expand the volume of the air chamber 4, air is passed through the air filter 8 and the check valve 9 into the air chamber 4 from the inlet 10. will be introduced. (Problem to be solved by the invention) However, in such a conventional throttle valve dosspot device for an internal combustion engine, when the throttle valve is below a predetermined opening, the lever 1, which is always linked to the opening and closing of the throttle valve, is closed. comes into contact with the plunger 3, and the movement of the plunger 3 is restricted by the variable jet needle 12, which restricts the flow rate of the air in the air chamber 4 to the atmosphere due to the movement of the diaphragm 5 fixed to the plunger 3. Because the throttle valve was designed to be damped, when the throttle valve opening was below a predetermined value, the throttle valve closing speed was always slow.
The reduction in engine speed is delayed regardless of the driver's intention to decelerate. Therefore, there was a problem in that the engine output (shaft torque) became positive even during braking, resulting in a poor sense of deceleration. On the other hand, Japanese Patent Laid-Open No. 59-65529 discloses that when the vehicle speed is above a predetermined value and the braking device is in operation, negative pressure in the intake pipe is introduced into the air chamber of the dart pot to reduce the dart pot function. Some proposals have been made to avoid deterioration of vehicle deceleration and fuel efficiency. however,
With this device, the dart pot function is reduced as long as the above conditions are met, so for example, if braking is started in the middle of acceleration from a start in a low gear, the dart pot will not work and the vehicle will suddenly decelerate. However, there was a problem that drivability was impaired. This is because when the engine is rotating at a high speed in a low gear, engine shaft torque fluctuations and engine braking act relatively strongly. The object of this invention is to solve the problems in the conventional throttle valve dumppot device for an internal combustion engine. (Means for Solving the Problem) Therefore, the throttle valve dosspot device for an internal combustion engine according to this invention includes a diaphragm that reduces the volume of the air chamber in conjunction with the closing operation of the throttle valve from a predetermined opening degree, and a A throttle valve dart pot device for an internal combustion engine having means for restricting the flow rate of air flowing out from a chamber, an open passage communicating the air chamber with the atmosphere, a solenoid valve interposed in the middle of the open passage, and a brake pedal. means for detecting a vehicle speed and a transmission gear position; and based on a signal from the detection means, the solenoid valve is activated only when braking, the vehicle speed is a predetermined value or more, and the transmission gear position is a predetermined high speed gear. and control means for driving the open passageway to open. (Function) The strength of the driver's intention to decelerate is determined based on the driving conditions of the vehicle, especially whether or not the brakes are operated, and when the brakes are operated, the solenoid valve is opened to allow the air chamber to communicate directly with the atmosphere through an open passage. Therefore, the dart pot function is canceled and the delay in closing the throttle valve is avoided to improve the feeling of deceleration. However, when the transmission gear is in a low gear position, the dart pot function is not released even if the brake is operated. Therefore, during deceleration in a low speed gear of the transmission where torque fluctuations associated with deceleration operations are easily detected, the opening degree of the throttle valve gradually decreases, thereby ensuring good drivability. Further, since the dart pot function is suppressed even when the transmission is in the neutral position, there is no possibility that the engine stalls when braking is applied from the neutral position of the transmission. (Example) Hereinafter, an example of this invention will be described with reference to the accompanying drawings. Fig. 1 is a sectional view including a partial block diagram showing an embodiment of this invention, and the same parts as in the conventional example shown in Fig. 4 are given the same reference numerals, and their explanation will be omitted. . First, to explain the configuration, the air chamber 4 in the case 7 equipped with the diaphragm 5 has an outflow port 11 through which air flows out through the variable jet needle 12, and an inflow port through which air flows in through the check valve 9. 10 are provided. An open passage 23 communicating the air chamber 4 with the atmosphere is connected to the case 7 of the diaphragm device 5, and a solenoid valve 14 is interposed in the middle of the open passage 23. This solenoid valve 14 is normally closed and closes the open passage 23, but when it is energized and driven by the control circuit 25, it becomes open and opens the open passage 23, opening the air chamber. 4 in direct communication with the atmosphere. In this embodiment, as means for detecting the braking state, vehicle speed, and transmission gear position, a brake depression signal SB issued in conjunction with the vehicle's braking device, a vehicle speed signal SN obtained from a speedometer or a vehicle speed sensor, and a transmission gear A gear switch signal SG obtained from a gear position switch or the like linked to the position is input to the control circuit 25. The relationship between each operating condition signal input to the control circuit 25 and the opening/closing control of the solenoid valve 14 is as shown in the following table.

[Table] However, the ON/OFF conditions for each signal are as follows. ○ Brake depression signal SB: ON when the brake pedal is depressed ○ Vehicle speed signal SN: ON at a predetermined speed, for example, 35 km/h or higher ○ Gear switch signal SG: ON in 3rd, 4th, and 5th gears" Explain the action. The driver releases the accelerator pedal to decelerate,
From the time the throttle valve closes to a predetermined TVO, the tip of the adjusting screw 2 pushes the plunger 3 in the same way as described in the conventional example, and the volume of the air chamber 4 is reduced by movement of the diaphragm 5. If the solenoid valve 14 is closed at this time, the air flow rate flowing out from the air chamber 4 is suppressed by the variable jet needle 12, so the moving speed of the diaphragm 5 is limited, and the speed at which the throttle valve closes becomes slow. The effect of this operation on improving drivability will be explained with reference to FIG. Without the dart pot device, the throttle valve opening (TVO) quickly returns to the idle position, as shown by the solid line in Figure 2A, so the engine output Pi and shaft torque, shown by the solid lines in Figure 2B and C, respectively. The decrease is rapid, causing the driver and passengers to feel a deceleration shock or jerky vibration when they release the accelerator pedal. However, in the case of a dart pot device like this embodiment, the reduction of the throttle valve opening is delayed as shown by the broken line in Fig. 2A, so the engine output Pi and shaft torque are As shown, it decreases smoothly, and there is no deterioration in drivability due to deceleration shock or jerky vibration. By the way, when the driver has a strong intention to decelerate and depresses the brake pedal, a brake depressing signal SB is input to the control circuit 25 from a brake lamp switch (not shown), and at this time the vehicle speed signal
If both SN and gear switch signal SG are ON (that is, the vehicle speed is 35 km/h or more and the transmission is in 1st gear,
(when neither the second speed nor neutral), the control circuit 25 drives the solenoid valve 14 in the valve opening direction. As a result, the electromagnetic valve 14 becomes open and opens the open passage 23, so that the air in the air chamber 4 is quickly discharged through the open passage 23, and the diaphragm 5 moves quickly. Therefore, the throttle valve quickly returns to the idle position. The effect of this operation on improving the sense of deceleration will be explained with reference to FIG. In the case of a conventional dart pot device, the speed at which the throttle valve closes continues to be delayed even when the brake is depressed, as shown by the broken line in Figure 3A. Since the engine output and shaft torque continued to be produced for a while, the driver felt a poor sense of deceleration. However, according to this embodiment, as shown by the solid line in FIG. 3A, when the brake is depressed, the throttle valve quickly returns to the idle position, so that the engine output and The shaft torque also decreases quickly, making it possible to improve the feeling of deceleration. However, as described above, even when the brake is operated, the solenoid valve 14 is not opened when the transmission gear is in the first or second gear with a large reduction ratio, or in neutral. This is because when the vehicle is running in a transmission gear position with a large reduction ratio, if the throttle valve is suddenly closed, a sudden change in the engine shaft torque and engine braking effect will be felt, causing discomfort. Also, in the case of neutral, this is to prevent stalling. In this way, the opening/closing control of the solenoid valve is performed by determining not only the brake pedal depression state but also the vehicle speed and transmission gear position, so it is particularly suitable for driving conditions such as low vehicle speed and low reduction gear position, which are often found in urban driving. Since the advantages of this invention can be fully utilized without causing deterioration in drivability due to sudden changes in shaft torque, the marketability of the vehicle can be further improved. (Effects of the invention) As explained above, the throttle valve dosspot device for an internal combustion engine according to this invention normally suppresses the speed at which the throttle valve closes from a predetermined opening, and also suppresses the speed at which the throttle valve closes from a predetermined opening. By opening the solenoid valve and opening the air chamber to the atmosphere only when the brakes are applied from the high gear of the transmission, the operation of the dart pot is canceled and the speed at which the throttle valve closes is increased, which reduces deceleration when the brakes are applied. It can eliminate discomfort. In addition, in this invention, the effect of the dart pot is maintained even when the vehicle speed is above a predetermined value and when braking in the low gear or neutral position of the transmission where torque fluctuations are easily felt. It is possible to prevent deterioration in drivability caused by sudden closing of the valve, and also to prevent stalling in the neutral position.

[Brief explanation of the drawing]

Fig. 1 is a sectional view including a partial block diagram showing an embodiment of this invention, Fig. 2 is a curve diagram comparing the effects of the presence and absence of a dart pot device during deceleration, and Fig. 3 is a diagram of a conventional device during deceleration. FIG. 4 is a sectional view showing an example of a conventional throttle valve dumppot device for an internal combustion engine. 1...Lever linked to opening and closing of the throttle valve, 2...
Adjustment screw, 3... Plunger, 4... Air chamber, 5
... diaphragm, 7 ... case, 11 ... outlet, 12 ... pariah jet needle (means for restricting air flow), 23 ... open passage, 14
... Solenoid valve, 25 ... Control circuit.

Claims (1)

[Claims for Utility Model Registration] An internal combustion engine comprising a diaphragm that reduces the volume of an air chamber in conjunction with the closing operation of a throttle valve from a predetermined opening degree, and means for restricting the flow rate of air flowing out from the air chamber. In the throttle valve dosspot device, an open passage communicates the air chamber with the atmosphere;
A solenoid valve installed in the middle of this open passage, means for detecting the brake depression, vehicle speed, and transmission gear position, and a signal from the detection means that detects when braking, when the vehicle speed is above a predetermined value, and when the transmission gear is detected. A throttle valve dart pot device for an internal combustion engine, comprising: control means for driving the solenoid valve to open the open passage only when the position is a predetermined high speed gear.