JPS6329035A - Stall preventer of internal combustion engine for automobile - Google Patents

Abstract

PURPOSE:To prevent an engine stall from occurring before it happens, by opening a control valve inside a passage bypassing a throttle valve, and reopening fuel injection at a time when three conditions that throttle valve opening is small, decrement in an engine speed is large and a car speed is slow are satisfied during fuel-cut controlling. CONSTITUTION:During vehicle driving, an electronic control unit 12 calculates a fuel injection quantity on the basis of each output signal out of a speed sensor 9 and a suction pressure sensor 10. And, at the time of engine deceleration, this control unit stops fuel injection out of a fuel injection valve 5 and performs such control as reopening the fuel injection when an engine speed goes down up to the specified revolution. In this case, a bypass passage 7 is installed in a suction passage 4 so as to bypass a throttle valve 6, and a control valve 8 is installed in this passage 7 side by side. And, when three conditions that throttle valve opening is small, decrement of the engine speed is large and a car speed is slow are satisfied in fuel-cut controlling, the control valve 8 is controlled for opening and simultaneously the fuel-cut state is released.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for preventing a fuel-injected internal combustion engine installed in an automobile from stalling when the clutch is engaged. It is.

[Conventional technology and its problems]

In recent fuel-injected internal combustion engines installed in automobiles, fuel injection is stopped (
When the engine speed drops to a predetermined speed, fuel injection is restarted to save fuel.

However, when a car is running, the clutch may be operated on and off during deceleration, so cutting fuel during deceleration means that the clutch must be disengaged once during deceleration, that is, when the fuel is cut off. There is a risk that the internal combustion engine may stall when the connection is reconnected later.

In particular, when the clutch is engaged and engaged during this fuel cut, when the engine speed tends to decrease, when the throttle valve opening is small, or when the vehicle speed is slow, the engine stalls frequently. It occurred in

The present invention provides such a fuel injection internal combustion engine,
The object of the present invention is to provide a device that prevents the occurrence of a stall due to fuel cut during deceleration.

Means for Solving Problem C] In order to achieve this object, the present invention calculates the amount of fuel injected into the engine from the amount of intake air into the engine or the intake pressure in the engine and the rotational speed of the engine. means for controlling the
In an internal combustion engine for an automobile, which is equipped with a fuel cut means that stops fuel injection when the engine is decelerated and resumes fuel injection when the engine speed drops to a predetermined speed, While a control valve is provided in a bypass passage for the throttle valve, when the fuel cut means stops fuel injection, the opening degree of the throttle valve is small, the engine speed decreases at a large rate, and the vehicle speed increases. Only when the three slow conditions are met, the control valve in the bypass passage is opened and the fuel injection stopper is released from the fuel injection stop state by the fuel cut means.

[Action/effect of the invention]

Stalls associated with clutch engagement/disengagement can occur when the clutch is engaged/disconnected when the opening of the throttle valve is small in the fuel cut state during deceleration, and when the clutch is engaged/disconnected when the rate of decrease in engine speed is large in the fuel cut state. This is likely to occur when the clutch is engaged and engaged when the vehicle speed is slow, such as when starting with a fuel cut, and when the clutch is engaged and engaged when the vehicle speed is slow, such as when starting with a fuel cut. By canceling the release, the engine speed can be increased, so when the fuel injection is stopped as described above, the throttle valve opening is small.
Moreover, only when three conditions are met, in which the rate of decrease in the engine speed is large and the vehicle speed is slow, the control valve in the bypass passage is opened and the state in which fuel injection is stopped by the fuel cut means is released. By configuring
This makes it possible to reliably prevent the engine from stalling due to clutch on/off operation.

In this case, the cancellation of the fuel injection stop state is as follows:
Since this is performed only when the three conditions are satisfied as described above, the number of times the stoppage of fuel injection is canceled can be limited to an extremely small number of times.

Therefore, according to the present invention, it is possible to reliably prevent the engine from stalling when the clutch is engaged and engaged during deceleration, without significantly reducing the fuel saving effect caused by stopping fuel injection. .

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, reference numeral 1 indicates a multi-cylinder internal combustion engine mounted on an automobile (not shown). Passage 4 is connected,
The intake manifold 2 is provided with fuel injection valves 5 for each of the cylinders.

The intake passage 4 is provided with a throttle valve 6 and a bypass passage 7 for the throttle valve 6, and a control valve 8 is provided in the bypass passage 7.

The internal combustion engine 1 includes a rotation sensor 9 for detecting the rotational speed (NE) of the crankshaft in the internal combustion engine 1, and the intake passage 4 includes a rotation sensor 9 for detecting the rotation speed (NE) of the crankshaft in the internal combustion engine 1. The throttle valve 6 is provided with an intake pressure sensor 10 for detecting the intake pressure, and a throttle sensor 11 for detecting the opening (TA) of the throttle valve 6.

Reference numeral 12 in the figure indicates that each of the fuel injection valves 5 receives signals from the rotation sensor 9, intake pressure sensor 10, throttle sensor 1), and vehicle speed sensor 3 of the automobile.
The bypass passage 7
The electronic control unit for controlling the control valve 8 inside is shown.

The electronic control unit 12 has a built-in ROM that stores the basic injection amount as a two-dimensional map using the intake pressure downstream of the throttle valve 6 and the engine speed as parameters, and stores the fuel for each cylinder. The amount of fuel injected from the injection valve 5 is determined by the rotational speed detected by the rotational sensor 9 (
Based on the intake pressure detected by the intake pressure sensor 10 and the intake pressure sensor 10, the injection amount is controlled to the basic injection amount read from the two-dimensional map, and fuel injection from each fuel injection valve 5 is stopped when the engine is decelerated. However, the main routine includes control for restarting fuel injection when the engine speed drops to a predetermined speed, either once the engine rotates or at appropriate intervals.

Furthermore, this electronic control unit 12 includes an interrupt routine that performs the following control during the main routine.

That is, this interrupt routine executes the bypass only when three conditions are met: the throttle valve opening is small, the rate of decrease in engine speed is large, and the vehicle speed is slow. It opens the control valve 8 in the passage 7 and performs control to cancel the fuel injection stop state.

To explain in more detail, this interrupt routine is as shown in FIG. 2. First, in step S1, it is determined whether or not the control valve 8 is open. If the control valve 8 is closed, in step S2, The rotation speed (NE) of engine 1 is the rotation speed (NB) when fuel injection is stopped.
It is determined whether or not it is less than or equal to the fuel car/h state, and if the fuel is not being cut, the process returns to the main routine, but when the fuel is being cut,
In step S3, it is determined whether or not the opening degree (TA) of the throttle valve 6 is below a certain value (for example, 20 degrees from fully closed), and if the opening degree (TA) of the throttle valve 6 is greater than the above value, the clutch Since there is little risk of a stall occurring due to engagement of the clutch, the program returns to the main routine. When the opening degree (TA) of the throttle valve 6 is small, there is a high risk of a stall occurring due to engagement of the clutch, so step S is performed.
4, the differential value (DL
It is determined whether or not TNE) is, for example, less than -25 rpm, that is, whether the rate of decrease in the rotational speed of the engine 1 is large or small.

When the rate of decrease in the rotational speed of the engine 1 is small, that is, when the rotational speed of the engine 1 is gradually decelerated, there is little risk of a stall occurring due to clutch engagement, so the process returns to the main routine. When the rate of decrease in the number of clutches is large, that is, when the engine decelerates rapidly, there is a high possibility that a stall will occur due to engagement and disengagement of the clutch, so the process moves to step S5.

In this step S5, it is determined whether or not the vehicle speed of the vehicle is slower than a certain value (for example, 10 kffi/h), and if the vehicle speed is faster, the torque required to accelerate the vehicle is small and the clutch is engaged and engaged at this time. However, when the vehicle speed is slow, a large amount of torque is required to accelerate the vehicle, and if the clutch is engaged and engaged at this time, there is a high risk of stalling. Therefore, the process moves to step S6, where the fuel cut state is canceled and the control valve 8 in the bypass passage 7 is opened to perform stall prevention idle up. Next, in step S7, the stall prevention idle amplifier is memorized, and then the process returns to the main routine.

On the other hand, when the control valve 8 is open in step S1, the process moves to step S8, where the rotational speed of the engine 1 (NE
) is determined to be DLTNE≧0, and if DLTNE≧O, that is, if the rotation speed (NE) of engine 1 is still being decelerated, return to the main routine. , the stall prevention up state continues, but DLTNE! When it is 0, that is,
When the rotational speed of the engine 1 stops decelerating or, conversely, increases, the control valve 8 is closed in step SIO via step S9, and the control valve 8 is closed in step SIO.
After canceling the memory of the stall prevention idle app 7 with l, the program returns to the main routine.

By going through the interrupt routine shown in Figure 2, the following three conditions are met: the throttle valve opening is small, the rate of decrease in engine speed is large, and the vehicle speed is slow while fuel injection is being stopped. Only when the fuel is filled up, the control valve 8 in the bypass passage 7 is opened and so-called stall prevention idle-up control is performed to cancel the fuel injection stop state, and the engine shuts off during the fuel cut.
This makes it possible to reliably prevent stalls from occurring when the chain is operated intermittently.

In the above embodiment, the amount of fuel injected into the engine was controlled to the basic injection amount determined using the intake pressure in the engine and the engine rotation speed as parameters, but the present invention controls the amount of fuel injected into the engine. It goes without saying that the present invention can also be applied to the case where the injection amount is controlled to a basic injection amount determined using the amount of intake air to the engine and the engine speed as parameters.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart. 1...Internal combustion engine, 2...Intake manifold, 3
...Air cleaner, 4...Intake passage, 5...
・Fuel injection valve, 6...throttle valve, 7...bypass passage, 8...control valve, 9...rotation sensor, 10...intake pressure sensor, 11...・Throttle sensor, 12...Electronic control unit, 13
····Vehicle Speed Sensor.

Claims (1)

[Claims] (1) means for controlling the amount of fuel injected into the engine to a value calculated from the amount of intake air to the engine or the intake pressure in the engine and the engine rotational speed; A control valve is provided in a bypass passage for a throttle valve in an intake system of an internal combustion engine for an automobile, which is equipped with fuel cut means for restarting fuel injection from the point when the number of revolutions falls to a predetermined number of revolutions. On the other hand, while the fuel injection is stopped by the fuel cut means, only when three conditions are met: the opening degree of the throttle valve is small, the rate of decrease in the engine speed is large, and the vehicle speed is slow. 1. A stall prevention device for an internal combustion engine for an automobile, comprising means for opening a control valve in a passage and releasing a state in which fuel injection is stopped by the fuel cut means.