JP2930663B2 - Operation control device for two-cycle engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine operation control device including a fuel injection valve, a lubricating oil pump, and a catalyst, and more particularly to a lubricating oil supply system such as a lubricating oil pump. The present invention relates to improvement of an operation method when a failure occurs.

[Conventional technology]

Generally, an engine is provided with a lubricating oil supply system,
In a two-stroke engine, lubricating oil is supplied to the crankshaft bearing,
It is supplied to the cylinder wall, the intake pipe, etc., and is supplied to the crankshaft bearing, valve operating mechanism, etc. in a four-cycle engine.

[Problems to be solved by the invention]

In an engine provided with the above-mentioned lubricating oil supply system, if the lubricating oil pump or the supply path breaks down, the engine may be damaged in the worst case. In order to avoid this problem, it is necessary to stop the engine when the lubricating oil supply system fails.

Incidentally, an engine is generally provided with a catalyst for purifying exhaust gas. If an engine equipped with this catalyst is configured to stop the engine when the lubricating oil supply system fails, the unburned gasoline in the exhaust gas will increase depending on the stop procedure, causing the catalyst to abnormally heat up and burn out. It is feared that.

The present invention has been made in view of the above circumstances, and provides an operation control device for an engine that can avoid burning of a catalyst when the engine is stopped when a failure of a lubricating oil supply system occurs. The purpose is.

[Means for solving the problem]

As shown in FIG. 1, the present invention provides a fuel injection valve 31 for injecting fuel directly into a cylinder or an intake pipe, a cylinder lubrication pump for supplying lubricating oil from a lubricating oil tank to an inner wall surface of a cylinder, and A lubricating oil supply system 32 having a plurality of lubricating oil pumps including a crankshaft lubricating pump for supplying lubricating oil from a lubricating oil tank to a journal bearing portion of the crankshaft;
In the operation control device for a two-stroke engine provided with a catalyst for purifying exhaust gas, a failure detecting means 33 for detecting a failure of each lubricating oil pump of the lubricating oil supply system 32; When a predetermined number or less of pumps fail, the engine output is suppressed as the number of failed pumps increases, and when the number of pumps exceeds the predetermined number, the fuel injection by the fuel injection valve is stopped and then the ignition system is switched off. Operation control means for stopping the engine by stopping
It is characterized by having 35.

In the present invention, the delay time from the stop of fuel injection to the stop of ignition is reduced so that the amount of unburned gas in the exhaust gas is sufficiently reduced, specifically, to such an extent that the temperature of the catalyst is not abnormally raised. It will be set as follows.

[Action]

According to the operation control device of the present invention, when a predetermined number or less of the plurality of lubricating oil pumps fails, the engine output is suppressed as the number of failed pumps increases, and the number of failed pumps exceeds the predetermined number. Since the engine is sometimes stopped, it is possible to prevent the engine from being damaged due to poor lubrication and to avoid the inconvenience caused by the immediate stop of the engine. Then, when stopping the engine, the fuel injection was stopped first, and then the ignition was stopped.
The amount of unburned gas in the exhaust gas decreases, abnormal temperature rise of the catalyst can be avoided, and the life of the catalyst can be extended. By the way, when the ignition is stopped at the same time as the fuel injection is stopped, for example, in the case of a crankcase compression type two-stroke engine, a large amount of unburned gasoline remains from the intake pipe to the crankcase. There is a concern that the temperature will rise and the life of the catalyst will decrease. In the present invention, since the ignition stop is delayed, it is possible to completely burn the residual air-fuel mixture,
Abnormal temperature rise of the catalyst can be avoided.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

2 to 5 are views for explaining an operation control device of a direct injection two-stroke engine according to one embodiment of the present invention. FIG. 2 is a schematic configuration diagram, and FIG. FIG. 4 is a diagram showing an example of a failure detection method of a supply system, FIG. 4 is a diagram showing an operation area, and FIG. 5 is a flowchart.

In the drawing, reference numeral 1 denotes a water-cooled two-cycle parallel three-cylinder engine configured to directly inject air and fuel into a cylinder, and the engine 1 has three cylinders (cylinders) 3 a on a crankcase 2. It has a structure in which a cylinder body 3 and a cylinder head 4 formed in parallel in the axial direction are stacked and fixed by bolts.

Above each cylinder 3a of the cylinder head 4, there is provided a valve mechanism 17 for opening and closing the cylinder side opening of the compressed air chamber.
A main fuel injection valve 18 for injecting fuel into the inside and a spark plug 19 protruding into the combustion chamber are mounted. This spark plug 19
, The voltage of the battery 22 is supplied via the igniter 15 and the ignition coil 16.

The piston 5 inserted into the cylinder 3a is connected to a crankshaft 6 via a connecting rod 6b, and the crank arm 6a of the crankshaft 6 is accommodated in a crank chamber 2a. Each intake port formed in each of the crank chambers 2a is provided with a reed valve 7 for opening and closing the intake port, and further connected to a branch pipe of an intake manifold 8. A throttle valve 9 is disposed in a junction pipe of the intake manifold 8. Although not shown, the throttle valve 9 is opened and closed by a servomotor. An auxiliary fuel injection valve 13 is provided upstream of the throttle valve 9 and an air flow meter is provided upstream thereof.
10 are sequentially arranged, and an air cleaner 11 is further connected.

Although not shown, a branch pipe of an intake manifold is connected to an exhaust port opening to the cylinder 3a,
A catalyst for purifying exhaust gas is provided in the middle of an exhaust pipe connected to a junction pipe of the manifold.

Reference numerals 21a to 21c denote lubricating oil pumps, which are configured to move a plunger forward and backward by a built-in electromagnetic coil 21d (see FIG. 6). When the plunger moves to a fully open position and a fully closed position, mechanical vibration is reduced. Occurs. These lubricating oil pumps 21a to 21c supply the lubricating oil from the lubricating oil tank 20 to the bearing of the air pump 25, the inner wall surface of each cylinder 3a,
To each journal bearing.

Reference numeral 14 denotes an ECU, which receives an engine speed signal a, an air flow rate signal b, an opening signal c of an accelerator pedal 24, and the like.
The control signals A to E are supplied to the valve mechanism 17, the main fuel injection valve 18, the igniter 15, the sub fuel injection valve 13, and the lubricating oil pumps 21a to 21c.
Is output.

The ECU 14 functions as a failure detection unit for the lubricating oil pumps 21a to 21c, and as an engine stop unit for gradually reducing or immediately stopping the engine output when a failure occurs. To stop the engine, the main fuel injection valve 18 and the sub fuel injection valve 13 are stopped, and the igniter 15 is stopped after a predetermined delay time has elapsed. Note that the delay time is determined by experimentation or the like to determine a time during which the amount of unburned gas remaining in the exhaust gas can be reduced to a level that does not cause abnormal temperature rise of the catalyst.

FIG. 3 shows an example of a failure detection method for the lubricating oil pumps 21a to 21c. In this example, the lubricating oil pumps 21a to 21c
, A shock sensor 23 is mounted on the ECU, and the ECU 14 determines occurrence of a pump failure based on an output waveform from the sensor 23. This is because, as shown in FIG. 3 (b), when the sensor output fluctuates greatly due to mechanical vibrations generated when the plunger of the lubricating oil pump moves to the fully open position and the fully closed position, the pump is operating normally. When the fluctuation waveform is no longer generated, it is determined that a failure has occurred.

FIG. 4 is a diagram for explaining a method of performing a stepwise cut of the engine output according to the degree of pump failure. For example, when all the lubricating oil pumps 21a to 21c are stopped at once, the fuel injection is immediately stopped, and the ignition is stopped after a predetermined delay time has elapsed. On the other hand, for example, when only one crankshaft bearing pump is stopped, the operation is performed in the area A in the figure, and when the number of failed pumps is large, the operation is performed in the area B in the figure.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

The ECU 14 first reads the remaining oil amount to determine whether the remaining amount is insufficient (steps S1 and S2). If the remaining amount is insufficient, the ECU 14 turns on the oil warning light (step S3), and diagnoses the failure of the oil supply system. To determine whether a failure has occurred (steps S4 and S4).
Five). If no failure has occurred, the process returns to step S1, and if a failure has occurred, a warning is issued and it is determined whether or not to perform stepwise output cutting (steps S6, S7).

If it is determined that the gradual output cut is not sufficient, such as when all the pumps are stopped, a warning sound for stopping the engine is generated, and after a lapse of a predetermined time, the main fuel injection valve 18 is stopped.
And the auxiliary fuel injection valve 13 is stopped (steps S8 to S1).
0). Then, after a predetermined delay time has elapsed, the igniter 15 is stopped (steps S11 and S12).

On the other hand, when stepwise output cut is performed as in the case where the pump failure is minor, the engine speed, output, and intake air amount are set, for example, in the region A of FIG. 4 (step S13,
S14), while continuing the operation in the area A, step S1
Return to

As described above, according to the apparatus of the present embodiment, when the lubricating oil pump fails, if the degree is small, the output is gradually reduced to operate at a low rotation speed and a low load. Is stopped so that damage to the engine due to poor lubrication can be avoided.

When the engine is stopped, the fuel injection is stopped first, and the ignition system is stopped after a predetermined delay time has elapsed. Therefore, the residual gasoline is completely burned to reduce the amount of unburned gas in the exhaust gas. It is possible to avoid abnormal temperature rise of the catalyst and extend the life of the catalyst.

In the above embodiment, the failure of the lubricating oil pump was detected based on the presence or absence of mechanical vibration.
The disconnection of the electromagnetic coil 21d of the pump may be detected by the circuit shown in FIG.

In FIG. 6, I and O are input terminals and output terminals, Tr1 and Tr2 are transistors that are turned on when the base voltage is high and low, respectively, R1 to R4 are current limiting resistors, and Vcc is a battery voltage.

In this failure detection circuit, when the electromagnetic coil 21d is normal, when the drive signal to the input terminal I is high, the transistor Tr1 turns on and the transistor Tr2 turns off,
The battery voltage drops to ground, the output at output terminal O goes to zero, and conversely, when the input is low, the output is the battery voltage. As a result, the output waveform shows the waveform in the normal state shown in FIG. 6 (b).

On the other hand, when the electromagnetic coil 21d is disconnected, the output of the output terminal O becomes zero irrespective of whether the input signal is high or low, as shown in the abnormal waveform in FIG.
Disconnection can be detected.

In the above embodiment, the failure of the lubricating oil pump itself is detected. However, in the present invention, the failure of the pump drive circuit may be detected from the point that a drive signal is not output from the ECU within a predetermined period.

〔The invention's effect〕

As described above, according to the engine operation control device of the present invention, when the lubricating oil supply system fails, if the number of failed pumps is equal to or less than a predetermined number, the engine output is suppressed as the number of failed pumps increases. When the number is exceeded, the engine is stopped, so that it is possible to prevent the engine from being damaged due to poor lubrication and to avoid the inconvenience of immediately stopping the engine.

When the engine is stopped, the fuel injection is stopped first, and the ignition system is stopped after a predetermined delay time, so that the engine can be prevented from being damaged due to poor lubrication, and the amount of unburned gas in the exhaust gas can be prevented. And the abnormal temperature rise of the catalyst can be avoided, and the life of the catalyst can be extended.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining the structure of the present invention, and FIGS. 2 to 5 are diagrams for explaining an operation control device for a direct injection two-cycle engine according to one embodiment of the present invention. FIG. 2 is a schematic configuration diagram, FIG. 3 (a) is a schematic configuration diagram showing a failure detecting means of the pump, FIG. 3 (b) is a waveform diagram thereof, and FIGS. 4 (a) and 4 ( b) is an engine speed-output characteristic diagram for explaining the operation range,
FIG. 5 is a flow chart, FIG. 6 (a) is a circuit diagram showing another example of the pump failure detecting means, and FIG. 6 (b) is a waveform diagram thereof. In the drawing, 1 is a direct injection two-stroke engine, 3a is a cylinder (cylinder), 8 is an intake manifold (intake pipe),
14 is an ECU (operation control device), 13, 18, and 31 are fuel injection valves, 21a
21c is a lubricating oil pump, 32 is a lubricating oil supply system, 33 is a failure detecting means, 35 is an engine stopping means, 15 is an igniter, 34
Is an ignition system.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI F02D 17/04 F02D 17/04 M (58) Field surveyed (Int.Cl. ⁶ , DB name) F01M 1/22-1 / 26 F02D 17/00-17/04

Claims (1)

(57) [Claims] 1. A fuel injection valve for injecting fuel directly into a cylinder or an intake pipe, a cylinder lubrication pump for supplying lubricating oil from a lubricating oil tank to an inner wall surface of a cylinder, and a lubricating oil from a lubricating oil tank. An operation control device for a two-stroke engine including a lubricating oil supply system having a plurality of lubricating oil pumps including a crankshaft lubricating pump for supplying to a journal bearing of a crankshaft, and a catalyst for purifying exhaust gas,
Failure detecting means for detecting a failure of each lubricating oil pump in the lubricating oil supply system; and, when a predetermined number or less of the plurality of lubricating oil pumps fail, the engine output is suppressed as the number of failed pumps increases. And an operation control means for stopping the engine by stopping the fuel injection by the fuel injection valve and then stopping the ignition system when the pump breaks down beyond the predetermined number. Operation control device for cycle engine.