JPS5920545A - Controller of engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of hot locking at a restarting time after an engine stops running, by constituting a device such that, when the number of revolutions of an engine is reduced lower than the number of revolutions which is set lower than the number of idle revolutions, the supply of the fuel from a fuel feeder is limited. CONSTITUTION:In case an engine rotates with the number of revolutions which is higher than the number Nr of revolutions set lower than the number of idle revolutions, a control circuit 17 brings a 3-way electromagnetic valve 16 to a switching position allowing a negative pressure chamber 12e of a reflux control valve 12 to be communicated with a first negative pressure passage 13, and an EGR is conducted during normal operation. Meanwhile, if an engine is brought to a stop state and the number of revolutions of the engine is reduced lower than the set number Nr of revolutions, the 3- way electromagnetic valve 16 is brought to a switching position allowing the negative pressure chamber 12e to be communicated with a second negative pressure passage 15. As a result, the reflux control valve 12 is opened by a intense suction negative pressure, and in which case, the amount of the fresh air sucked is decreased by the amount of exhaust gas returned, and the amount of the fuel fed through a fuel nozzle 8 is decreased by said decreased amount.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an engine in which fuel from a fuel supply device is prevented from being continuously drawn into a cylinder due to inertia during a transition period when the engine is in transition from operation to stop. The present invention relates to a control device.

Generally, when an engine transitions from operation to stop, during the transition period, fuel from the fuel supply system continues to be sucked into the cylinder along with air due to inertia, and while the engine is not completely cooled down, it is heated by the engine heat and becomes air. There are some things that have become C. For this reason, if you try to restart the engine when it has not cooled down sufficiently, the vaporized air-fuel mixture will self-ignite using carbon, etc. adhering to the cylinder inner wall or piston as an ignition source. This causes a so-called locking phenomenon in which reverse torque acts on screws 1 to 1, making it difficult to start. This phenomenon is particularly noticeable in engines where the compression ratio is set high to improve fuel efficiency.

Therefore, to prevent the occurrence of the above-mentioned warm lock,
In d3 during the transition period when engine operation shifts to stop,
One idea is to limit the supply of fuel from the fuel supply system, but conventional systems that embody this idea are lζ devices, which prevent the engine run-on phenomenon in which combustion continues even after spark ignition is stopped. It is publicly known. J, please turn off the ignition switch for this lion prevention device.
When operated, the fuel supply from the fuel supply device is restricted in conjunction with the operation, thereby stopping combustion at the same time as spark ignition is stopped.

Therefore, if this run ∆ run prevention iL'JA setting is applied, it is possible to easily prevent warm lock.

For example, when the ignition switch is turned off, the exhaust gas is forcibly fed into the cylinder as an inert gas, thereby restricting the supply of fuel from the fuel supply device. ) are applicable.

However, C
Since this requires the ignition switch to be turned OFF, it will function even when the engine stops without the ignition switch being turned OFF, so-called engine stall, but the fuel supply from the fuel oil supply system will still continue. However, there is a drawback that the occurrence of warm lock cannot be reliably prevented.

The present invention has been made in view of this point, and is designed to limit the supply of fuel from the fuel supply device whenever the engine speed becomes lower than the set speed set below the idle speed. The purpose of this is to ensure that even when the engine stalls, the occurrence of a warm-up problem can be prevented.

In order to achieve the object, the present invention includes a fuel supply device that supplies fuel to an engine, a rotation speed sensor that detects the rotation speed of the engine, and an engine rotation speed signal of the rotation speed sensor that corresponds to the idle rotation speed of the engine. a fuel limiting device that limits the supply of fuel by the fuel supply device when the rotation speed is lower than the set rotation speed set below; The restriction device is activated to restrict the supply of fuel from the fuel supply device.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a first embodiment in which the present invention is applied to an engine equipped with a carburetor type fuel supply device, in which 1 is an engine, 2
are cylinder head 1a, cylinder block 1b and screw 1
3 is an intake boat, and 4 is an intake valve disposed in each of the intake bows 1 to 3.

Reference numeral 5 indicates an intake passage whose one end communicates with the combustion chamber 2 via the intake boat 3, 6 indicates an intake valve arranged in the intake passage 5 and controls the amount of intake air into the combustion chamber 2, and 7 indicates an intake passage. 8 is a fuel nozzle provided in the pendury part 7 of the intake passage 5, and 9V is an air cleaner provided at the other end of the intake passage 5. While controlling the intake air m with the throttle valve 6, the air from the air cleaner 9 and the fuel from the fuel nozzle 8 are mixed, and this mixture is passed through the intake vent 28.
A carburetor-type fuel supply device 10 is configured such that fuel is supplied from the engine 5 to the combustion chamber 2 via an intake boat 3.

Reference numeral 11 denotes an exhaust gas recirculation passage for recirculating exhaust gas from the engine 1 to the intake passage 5 downstream of the throttle valve 6; In the middle of the flow passage 11, there is a passage “11”.
A reflux control valve 12 is provided to control opening and closing. The recirculation control valve 12 has a valve body 1 that opens and closes the exhaust gas recirculation passage 11.
2a, a diaphragm 12C that supports the valve body 12a via a rod 12b, an atmospheric chamber 12d and a negative pressure chamber 12e defined by the diaphragm 12.0, and m equipment in the negative pressure chamber 12e. The negative pressure chamber 12e is connected to the intake passage 5 immediately upstream of the fully open throttle valve 6 through the first negative pressure passage 13, and therefore, except when the engine 1 is idling. During operation, by introducing negative intake pressure into the negative pressure chamber 12e through the '1st angular pressure passage 13, the diaphragm 12C is moved upward 1. : Exhaust gas that is biased to open the valve body 12a to open the exhaust gas recirculation passage 11 and recirculate the exhaust gas)! flow device 14
is configured.

A second negative pressure passage 15 is branched from the middle of the first negative pressure passage 13, and the branch part has a negative pressure chamber 12e of the reflux control valve 12 and a first or second negative pressure passage 13.15. A three-way solenoid valve 16 is provided to switch communication between the two. The three-way solenoid valve 16 connects the zero chamber 12e to the first negative pressure passage 1 when inactive.
3, the first negative pressure passage is connected to the intake passage 5 immediately upstream of the fully closed position of the throttle valve 6;
Rear) A second angular pressure passage connection that connects the negative pressure chamber 12e to the downstream side of the throttle valve 6 of the intake passage 5 via the second negative pressure passage 15 during operation when receiving a restriction signal from the control circuit 17. position (the position shown in the figure).

Furthermore, the above three-sided type v1. The operation of the L valve 16 is controlled by a control circuit 17. The control circuit 17 controls the idle speed of the engine 1 (for example, 700 r, l).

m) or less (for example, 20 Or).

The engine rotation speed signal value as a voltage signal from the set voltage generation circuit 18 which generates a set voltage corresponding to p, m> and the rotation speed sensor 19 which detects the engine rotation speed of the engine 1 is transmitted to the set voltage generation circuit. A comparator circuit 20 generates a limit signal when the set voltage is lower than the set voltage of 18, and a comparator circuit 20 that normally prevents the limit signal from passing through the comparator circuit 20.
[On the other hand, when the output from the starter switch 21 that detects the operation of the starter (not shown) of the starting device is received (when it is pulled, the passage of the above-mentioned trill limit signal is blocked and covered).
2, and an amplifier circuit 23 for amplifying the control signal that has passed through the gate 22, and outputs the amplified limit signal by the amplifier circuit 23 to the three-way solenoid valve 16.
is switched from the first negative pressure passage connection position to the second negative pressure passage connection position. As a result of the above, when the rotation speed is lower than the set rotation speed set below the idle rotation speed, the rotation speed sensor 1
The engine speed signal value from 9 is the set voltage generation circuit 18
voltage becomes lower than the set voltage of , a limiting signal is generated in the comparator circuit 20, and this limiting signal passes through the gate 22 and then goes to the amplifier circuit 2.
3 and output to the three-way solenoid valve 16,
switching the three-way solenoid valve 16 from the first negative pressure passage connection position to the second negative pressure passage connection position, closing the recirculation control valve 12, and recirculating the exhaust gas using the exhaust gas recirculation passage 11; As a result, the fuel restriction device 24 is configured to reduce and limit the amount of fuel supplied from the fuel nozzle 8 by reducing the intake amount of fresh air.

Furthermore, the above 2nd f? The +pressure passage 15 only allows air to flow from the throttle 25a and the negative pressure chamber 12e to the intake passage 5.
A delay device 25 of 4T is provided in conjunction with the h valve 2511, and by delaying the dilution of the intake negative pressure in the negative pressure chamber 120 of the recirculation control valve 12, the engine rotational speed is increased. This is to ensure reliable operation of the recirculation control valve 12 when the rotational speed becomes lower than the set rotational speed set to be lower than the idle rotational speed.

Next, we will explain the operation of the above embodiment. When the engine 1 is rotating at a rotation speed higher than the set rotation speed (for example, 20 Or, p, m) set below the idle rotation speed, The three-way solenoid valve 16 is in the first angular pressure passage connection position, and the recirculation control valve 12 is operated by the intake negative pressure acting on the first negative pressure passage 13 in response to the closing operation of the throttle valve 6, and as a result, the normal During operation, the exhaust gas is recirculated by closing the recirculation control valve 12, and during idling at a rotation speed higher than the set rotation speed (first negative pressure passage 1
3 is located in the second flow of the throttle valve 6, so the recirculation of exhaust gas is stopped by the closing operation of the recirculation control valve 12.

After that, the engine stalls, and the rotation speed of the engine 1 is set to a set rotation speed below the idle rotation speed (for example, 20
When the engine speed signal value from the speed sensor 19 becomes lower than the set voltage of the set voltage generation circuit 18, the control circuit 17 outputs a limit signal. is output to the three-way solenoid valve 16, and the three-way solenoid valve '16 is switched from the first negative pressure passage connection position to the second negative pressure passage connection position. The closed operation is controlled by the high intake negative pressure acting on the exhaust gas recirculation passage 11, and the exhaust gas is recirculated through the passage 11 to the intake passage 5 downstream of the throttle valve 6. As a result, the intake amount of fresh air is reduced by this exhaust gas recirculation valve, and due to this reduction in the intake amount of fresh air, the amount of fuel supplied from the combustion nozzle 8 is reduced accordingly. .Therefore,
Since the supply of fuel from the fuel nozzle 8 is reliably restricted even when the engine is running (~), when restarting the engine after stalling,
) The occurrence of warm lock can be prevented.

In addition, when restarting the engine after stalling, the gate 22 of the control circuit 17 is activated by the output from the starter switch 21 to prevent the output of the limit signal from the comparator circuit 2Q to the amplifier circuit 23. The valve 16 becomes inactive and switches to the first negative passage connection position, and the recirculation of exhaust gas is stopped by the closing operation of the recirculation control valve 12.
The restart is smooth.

FIG. 2 shows a second embodiment in which the present invention is applied to an engine equipped with a fuel injection type fuel supply device.
Or, p, m), the fuel injection from the fuel injection valve is forcibly stopped. still,
For the same configuration as the above embodiment, the same reference numerals are used (q-
The explanation will be omitted.

That is, in FIG. 2, 26 is a fuel oil valve 81 disposed downstream of the throttle valve 6 in the intake passage 5;
Reference numeral 27 denotes an air amount detector for detecting the amount of intake air using an air flow meter (not shown in the figure) disposed upstream of the slot valve 6 of the intake passage 5; 28, the air amount detector 27;
This is an injection pulse generation circuit that generates an injection pulse corresponding to the intake air amount signal of the fuel injection amount according to the intake air amount signal. 1 watch valve 26 burned through 1-29
A single fuel injection type fuel supply device 10' is constituted by injecting fuel in accordance with the amount of intake air from the fuel injection valve 26 and supplying it into the -C combustion chamber 2. are doing.

Further, 29 is an injection pulse generation circuit 28 and a fuel injection valve 26.
Goo 1-22 in the control circuit 17' interposed between
The second gate 29 normally allows output of the injection pulse from the injection pulse generation circuit 28 to the fuel injection valve 26, while the second gate 29 is controlled by a signal from the control circuit 17'. When the limit signal from the comparator circuit 20 is inputted through the gate 22, the negative signal is stored in the ignition valve 11 and the Fukawa valve 26.
The fuel control device 24' is controlled by the second gooses 1 to 29 and the control circuit 17'.
It consists of The rest is the same as the first embodiment.

Therefore, when the engine 1 is rotating at a rotational speed higher than the set rotational speed set below the idle rotational speed, the injection pulse of the injection pulse generation circuit 28 is
-29 and is output to the fuel injection valve 26, and fuel corresponding to the amount of intake air is injected from the fuel injection valve 26. On the other hand, when the engine speed is 1 o'clock, the engine speed is set below the idle speed (e.g. 20Or, p, m>
When it becomes lower, a limit signal is generated in the comparator circuit 20 connected to the fuel limiter 24', and this limit signal becomes
-22 [is output to the second gate 29, and the output of the injection pulse to the fuel injection valve 26 is blocked by the second gates 1 to 29, so that the fuel injection from the fuel injection valve 26 is forced. will be stopped. Therefore, it is possible to prevent the occurrence of a warm one-shot during a subsequent warm start.

As explained above, according to the present invention, when the engine speed becomes lower than the set engine speed set below the idle speed, the supply of fuel 1 from the fuel supply device is restricted. It is possible to reliably prevent the occurrence of a warm lock when restarting the engine after the engine has stalled, and it can be extremely effective in improving the warm startability of the engine after the engine has stalled.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 shows a first embodiment in which the present invention is applied to an engine equipped with a carburetor fuel supply system.
An overall schematic configuration diagram showing an embodiment, FIG. 2 shows an example in which the present invention is applied to an engine equipped with a 1'31 fuel injection type fuel supply system. FIG. 2 is an overall schematic configuration diagram showing a second embodiment. 1...Engine, 5...Intake passage, 6...S L]
Tour valve, 7... Venturi section, 8... Fuel nozzle, 9... Air cleaner, 10.10'...
Fuel supply device, 11... Exhaust gas recirculation passage, 12...
Reflux control valve, 15...Second negative pressure passage, 16...Three-way solenoid valve, 18...Setting type L "benshi circuit, 19...Rotation speed range, 20...Comparison circuit, 21... ... Starter Suite, 22... Goo 1~.24.24'...
Fuel restriction device, 26...Fuel injection valve, 27...Air amount detector, 28...Injection pulse generation circuit, 29...
Second gate.

Claims (1)

[Claims] (1) A fuel supply device that supplies fuel to the engine;
The engine rotation speed is detected by a rotation speed sensor, and when the engine rotation speed signal of the rotation speed sensor is lower than a set rotation speed set below the engine idling speed, the fuel supply by the fuel supply device is restricted. 1. An engine control device comprising a fuel control device.