JPH0979080A - Control method for fuel injection type two-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsiveness and enhance drivability at transition period of rapid acceleration, rapid deceleration, or the like, by detecting an amount of intake air used in the cycle in each combustion cycle and an operation condition necessary for the other arithmetic operation, and calculating ignition timing and a control amount of fuel injection during the cycle based on this detection. SOLUTION: In the case of controlling of operation of a fuel injection two-cycle engine 1 by a control device 40, a spark is generated in a sparking plug 5 in each combustion cycle. On the other hand, fuel is injection from injectors 102, 103, based on an engine speed, and engine load and/or intake air amount detected when a piston 7 is in a rising stroke, ignition timing, fuel injection amount and/or fuel injection timing are determined. Control is performed in such a manner that fuel injection is executed based on the fuel injection amount and/or the fuel injection timing, in the halfway of an ignition preliminary stroke comprising a scavenge/exhaust stroke and a compression stroke after ignition combustion after the rising stroke, and that a spark is generated in the spark plug 5 based on the ignition timing, immediately after the ignition preliminary stroke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection type two-cycle engine for controlling fuel injection based on a detection result of engine operating conditions such as engine speed and engine load detected for each crankshaft rotation, The present invention relates to a method of controlling ignition timing and fuel injection in such a fuel injection type two-cycle engine.

[0002]

2. Description of the Related Art Without using a carburetor, an injector for fuel injection is arranged in an intake manifold, an intake port, a combustion chamber, etc., fuel is directly injected into intake air, and ignition is performed by a spark plug in the combustion chamber. Fuel injection spark ignition type engines have long been used in the field of high performance engines such as racing machines, but in recent years, advances in electronic technology have made it possible to easily perform ideal control in this type of engine. As a result, some 4-cycle engines for general passenger cars have started to use them.

In such a fuel injection type engine, in order to make the fuel injection always correspond to the operating state of the engine, the engine operating state such as the engine speed and the engine load is detected for each combustion cycle. Controlling the fuel injection timing and the fuel injection period (fuel amount) in the same combustion cycle based on the detection result, and controlling the ignition timing so as to match the fuel injection based on the detection result. Is being considered.

The combustion cycle referred to in the present application means, regardless of whether or not combustion actually occurs, in a four-cycle engine, an intake stroke in which a piston descends with an intake valve open,
Two crankshaft rotations consisting of four strokes: a compression stroke in which the piston rises when the intake and exhaust valves are closed, an expansion stroke in which the piston descends in the same state, and an exhaust stroke in which the piston rises when the exhaust valve is open. Is a cycle consisting of Similarly, the combustion cycle for a two-cycle engine is irrespective of whether combustion actually occurs or not, with the combustion chamber as the main component, the piston rising stroke from the latter half of the scavenging stroke to the compression stroke, the expansion stroke, the exhaust stroke, and The cycle consists of one revolution of the crankshaft, which consists of the piston descending stroke up to the first half of the scavenging stroke.

[0005]

By the way, in the field of motorcycles, outboard motors, etc., two-cycle engines are generally used in many models. Development of a fuel injection engine using a gasoline injection system like this is under consideration, but even in that case, as in the case of a 4-cycle engine, detection results of engine operating conditions such as engine speed and engine load are still obtained. It is necessary to control fuel injection and ignition timing based on the above.

However, as the piston moves upward, fresh air is sucked into the crankcase from the intake pipe, and at the same time, compression and ignition of the air-fuel mixture based on the fresh air already sucked into the cylinder above the piston are caused. The two-cycle engine is a four-cycle engine in which the fresh air that has been sucked into the crankcase is sent from the inside of the crankcase through the scavenging holes into the cylinder above the piston by the downward movement of the piston due to the explosion after ignition. When the fuel injection and the ignition timing are simultaneously controlled in the same cycle based on the detection result of each combustion cycle as in the case of No. 1, after the ignition by the controlled ignition timing is completed, the fuel injection corresponding to the ignition is performed. Since air is supplied to the cylinder above the piston, the amount of fuel burned does not match the ignition timing. There is a problem that Jill.

An object of the present invention is to solve the problems of controlling the ignition timing and the fuel injection in the fuel injection type two-cycle engine as described above, and more specifically, in the combustion chamber in each cycle. The ignition timing can be given in proportion to the amount of fuel being supplied, the engine can always be operated in good condition, abnormal combustion can be avoided, and fuel economy, exhaust gas, and output characteristics can be optimized. It is an object of the present invention to provide a method for controlling a fuel injection type two-cycle engine capable of achieving the above. If the engine speed and engine load are detected as the engine operating state and the fuel injection amount and ignition timing are set accordingly, fuel consumption, exhaust gas, and output characteristics suitable for the engine operating state can be obtained. However, after detecting the engine operating state, injecting the fuel injection amount according to it,
Even if ignition is performed at a corresponding ignition timing, if there are many cycles in between, it is sufficient to obtain fuel consumption, exhaust gas, and output characteristics that match engine operating conditions, especially in the transient state of acceleration or deceleration. It cannot be achieved. An object of the present application is to provide a control method for a fuel injection type two-cycle engine, which has good responsiveness even in a transient state and can optimize fuel consumption, exhaust gas, and output characteristics.

[0008]

In order to solve the above-mentioned problems and to achieve the object, the present invention provides a spark plug in the combustion chamber above the piston and a check valve in the crank chamber below the piston. Injector for fuel injection is installed in the crank chamber including combustion chamber or scavenging passage, and sparks are blown to the spark plug every crankshaft rotation while fuel is injected from the injector. In a two-cycle engine, the ignition timing and the fuel injection amount and / or the fuel injection timing are determined based on the engine speed and the engine load detected when the piston is in the ascending stroke, and / or the intake air amount, and the piston is raised. In the middle of the ignition preparatory process including the scavenging exhaust process and the compression process after the ignition and combustion after the process, the fuel injection amount, A fuel injection type two-cycle engine control method characterized in that fuel is injected based on the fuel injection timing and / or the fuel injection timing, and a spark is blown to the spark plug based on the ignition timing immediately after the ignition preparation process. I will provide a.

In a preferred embodiment, an engine speed sensor and an engine load sensor or / and an intake air amount sensor are arranged as the detection means, and the plurality of sensors are used to detect the engine during the period when fresh air is sucked into the crank chamber. The feature is that the driving state is detected.

[0010]

According to the above control method, the fresh air drawn into the crank chamber at the time of detection is injected with fuel based on the fuel injection amount and / or the fuel injection timing determined based on the detection result, and the combustion is performed. The chamber is filled with the air-fuel mixture based on the injected fuel, and sparks fly to the spark plug at the ignition timing determined based on the detection result, and the combustible air-fuel mixture is ignited and burned. That is, instead of the above combustion cycle mainly composed of the combustion chamber, detection, ignition timing, and fuel injection amount in the crank chamber mainly composed of intake stroke, scavenging stroke, compression stroke, and ignition Alternatively, and / or the fuel injection timing is determined, and the fuel injection and ignition are performed based on these various amounts, so that the response at the time of transition is good.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a control method for a fuel injection type two-cycle engine of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a fuel injection type two-cycle engine to which the ignition timing and fuel injection control method of the present invention is applied. The engine 1 is a single cylinder used as a drive source of a motorcycle. 2 cycle engine of which the main body is a cylinder head 2 and a cylinder block 3.
A combustion chamber 6 in which the discharge portion of the ignition plug 5 projects, and a cylinder hole in which a piston 7 is slidably housed in the cylinder block 3. 8, a crankshaft 9 provided with a balance weight (not shown) is pivotally supported on the crankcase 4, and the piston 7 and the crankshaft 9 are connected via a connecting rod 10. There is.

An intake port 11 opening into the crankcase 4 is formed in the crankcase 4, an intake pipe 12 extending from an air cleaner (not shown) is connected to the intake port 11, and a cylinder block is provided. 3, an exhaust port 13 opening to the cylinder hole 8 is formed, an exhaust pipe 14 is connected to the exhaust port 13, and the exhaust pipe 13 extends across the cylinder block 3 and the crankcase 4.
A scavenging passage 15 that communicates the inside of the cylinder hole 8 and the inside of the crankcase 4 is formed.

Further, in the middle of the intake pipe 12 communicating with the inside of the crankcase 4, a grip (not shown) attached to an end portion of the steering handle is operated through a wire 20 and a throttle pulley 21. A throttle valve 22 that is opened and closed is provided, and a reed valve 23 for preventing the backflow of the air-fuel mixture from the inside of the crankcase 4 is provided at the connecting portion between the intake pipe 12 and the intake port 11, and the throttle valve 22 An injector (fuel injection valve) 25 for injecting the fuel delivered by the fuel delivery pipe 24 into the intake pipe 12 at the opening period of the reed valve 23 is provided between the reed valve 23 and the reed valve 23. ing.

Although not shown, the injector 25 pulls the plunger by magnetic force to open the nozzle portion only at the moment when a current flows through the solenoid coil in the injector 25, and while the nozzle portion is opened. Only the fuel supplied from the fuel supply pipe 24 is injected.

The exhaust port 13 of the cylinder block 2 opening in the cylinder hole 8 is driven by an actuator 26 such as a servomotor on the upper wall of the opening to change the upper end position of the opening of the exhaust port 13. Thus, an exhaust timing control valve 27 for adjusting the exhaust timing is provided, and an exhaust pipe 14 connected to the exhaust port 13 is driven in the middle by an actuator 28 composed of a servomotor or the like to throttle in a low speed range. An exhaust passage valve 29 is provided for preventing blow-through and stabilizing rotation.

Further, as a sensor for detecting the operating state of the engine 1, an accelerator position sensor is provided at the base of a grip (not shown), and an intake pipe 12 is provided downstream of the throttle valve 22. A temperature sensor 31 and an intake pipe pressure sensor 32 are provided, a cylinder head 2 is provided with a combustion chamber pressure sensor 33 and a knock sensor 34, and a crankcase 4 is provided with an engine speed detection sensor 35 and a crank angle detection sensor 36. A crank chamber pressure sensor 37 is provided, and an exhaust pipe temperature sensor 38 is provided in the exhaust pipe 14.

In order to control the operating condition of the engine 1 having the above structure, the CPU 40a
The control device 40 including the
Each of the above-mentioned sensors is connected to the input side of the exhaust timing control valve on the output side of the control device 40 which outputs a control current based on the detection result of the operating state of the engine input from each sensor. An actuator 26 for driving 27 and an actuator 28 for driving the exhaust passage valve 29 are connected, and an injector 25 for injecting fuel and ignition for controlling the ignition timing of the spark plug 5 are connected. The control device 41 is connected.

As shown in FIG. 1, 100 is a crank chamber,
Reference numeral 101 denotes an intake passage, and the reed valve 23 is arranged between the crank chamber 100 and the intake passage 101 as described above to prevent the reverse flow of fresh air. Reed valve 2 as this check valve
Instead of 3, a rotary valve composed of a notched disk that rotates in synchronization with the crankshaft 9 or a piston valve utilizing the opening / closing action of the piston 7 itself may be arranged.
In this case, in the rotary valve, the notch on the rising stroke of the piston 7 communicates the intake passage 101 and the crank chamber 100, and the lower end of the piston valve on the rising stroke of the piston 7 opens the intake port at the lower end of the cylinder hole 8 to allow intake. The passage 101 and the crank chamber 100 are made to communicate with each other. In addition, during the period in which the piston 7 descends and the sweep exhaust stroke is performed, this communication is not performed. Further, 102 is an injector arranged so as to desire the combustion chamber 6, and 103 is an injector arranged so as to desire the scavenging passage 15. These may be arranged alone, in combination with the injector 25, or plurally arranged together.

At least an accelerator position sensor and an intake pipe pressure sensor 3 are provided as sensors for detecting the above-mentioned driving state.
2. Using one or more of the engine speed detection sensor 35 and the intake pipe temperature sensor 31, based on the detection results, the ignition timing at which a spark is blown to the ignition plug 5 for each combustion cycle, and the injection injected from the injector 102. amount,
Determine the injection timing.

Further, an intake air amount sensor may be arranged as the detecting means. In addition, during the period when fresh air is sucked into the crank chamber 100, the plurality of sensors (for example, 32, 3
1, 35, etc.) to detect the operating state of the engine.

In addition, the injector 102 or 10
3, a spark is blown to the spark plug 5 for each combustion cycle, while fuel is injected from the injector 102 or 103, and the engine speed and engine load and / or engine speed detected when the piston 7 is in the ascending stroke for each fuel cycle. The ignition timing and the fuel injection amount or / and the fuel injection timing are determined based on the intake air amount, and in the middle of the ignition preparatory process including the scavenging exhaust stroke and the compression stroke after the ignition combustion after the ascending stroke of the piston 7. The fuel may be injected based on the fuel injection amount and / or the fuel injection timing, and the spark may be blown to the spark plug based on the ignition timing immediately after the ignition preparation process.

FIG. 2 is a time chart showing the relationship between the ignition timing and the fuel injection control operation according to the present invention, and the air inflow state into the engine. (A) shows the reed valve lift operation and the amount of air flowing into the crank chamber, (B) shows the amount of air flowing into the cylinder from the scavenging port, and (C) shows the timing of ignition and injection and the heat generation state. . Further, (D) shows a control flow.

As shown in FIG. 1A, in the reed valve 23 (FIG. 1), the piston 7 moves from the bottom dead center (BDC) to the top dead center (TD).
It opens in the ascending stroke toward C), and fresh air flows into the crank chamber 100. At almost the top dead center, the reed valve closes and the piston descends. As shown in (B), the scavenging port opens near the bottom dead center, and the fresh air in the crank chamber is sent into the cylinder. In the ascending stroke from the bottom dead center to the top dead center again, as shown in FIG. 6C, fuel is injected and the spark plug sparks near the top dead center. In this way, one combustion cycle (i) is completed. In the ascending stroke from bottom dead center to top dead center, the next cycle (i
+1) fresh air intake is performed as described above, and the same combustion cycle is repeated.

In the present invention, as shown in FIG. 3D, regarding one cycle (i), the amount of air flowing into the crank chamber in the piston ascending stroke of that cycle, the engine speed and load at that time, etc. Measures and detects the driving state,
Based on this detection data, the ignition timing, the fuel injection amount, and the timing are calculated during the piston lowering stroke of the cycle. Based on this calculation result, the fuel injection device (injector) and the ignition device (ignition plug) are operated during the piston ascending stroke immediately after that. When the ignition and injection of this cycle (i) are activated, the next cycle (i
+1) The intake air is measured and detected.

The control method of the present application is not limited to the one in which a spark is blown to the spark plug every one revolution of the crankshaft, but the combustion is performed by interrupting the ignition or interrupting the fuel injection for an arbitrary number of crankshaft revolutions. It is also effective for intermittent combustion operation that interrupts the combustion, and in the cycle in which combustion is actually performed, the combustion injection during the ignition preparation period in which the piston rises immediately before ignition and ignition is performed immediately before that cycle. By controlling based on the operating state detected when the piston rises in the cycle, stable intermittent operation is possible.

Furthermore, in the case of intermittent combustion operation,
The operating state may be always detected when the piston rises every time the crankshaft rotates, or the operating state may be detected only in the cycle immediately before the cycle in which combustion is actually performed.

Further, in a two-cycle engine consisting of a plurality of cylinders, when the cylinder deactivation operation in which a part of the cylinders is misfired is performed, the control method of the present invention is carried out for the operating cylinders, so that a stable cylinder deactivation operation is possible. .

[0029]

According to the control method of the fuel injection type two-cycle engine of the present invention as described above, for each combustion cycle, the amount of intake air used in that cycle and other operating conditions necessary for calculation are determined. The ignition timing and the control amount of the fuel injection are immediately calculated during the cycle based on the detected value, and the fuel injection and the ignition of the cycle are performed based on this control amount. Improves drivability during transient conditions such as sudden deceleration.

[Brief description of drawings]

FIG. 1 is a fuel injection type 2 to which a control method of the present invention is applied.
It is a longitudinal section explanatory view showing an outline of a cycle engine.

FIG. 2 is an explanatory diagram showing a relationship between a control operation and inflow air in the control method of the present invention.

[Explanation of symbols]

1: Fuel injection 2-cycle engine, 4: Crank case, 5: Spark plug, 6: Combustion chamber, 7: Piston, 8:
Cylinder hole, 12: intake pipe, 14: exhaust pipe, 23: reed valve, 25: injector, 40: control device, 41:
Ignition control device.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F02D 45/00 358 F02D 45/00 358H F02P 5/15 F02P 5/15 K

Claims (2)

[Claims] 1. A spark plug is provided in a combustion chamber above a piston, and an intake passage is connected to a crank chamber below the piston via a check valve to inject fuel into a crank chamber including a combustion chamber or a scavenging passage. In a two-cycle engine in which an injector is provided and a spark is blown to the spark plug at every crankshaft rotation, while fuel is injected from the injector, the engine speed and engine load detected when the piston is in the ascending stroke, or / And / or the ignition timing and the fuel injection amount or / and the fuel injection timing based on the intake air amount, and in the middle of the ignition preparatory process including the scavenging exhaust stroke and the compression stroke after the ignition combustion after the ascending stroke of the piston. In the fuel injection amount and / or the fuel injection timing in A control method for a fuel injection type two-cycle engine, characterized in that a spark is blown to a spark plug based on the ignition timing immediately after that. 2. An engine speed sensor and an engine load sensor or / and an intake air amount sensor are arranged as the detecting means, and the operating state of the engine is detected by the plurality of sensors during a period when fresh air is sucked into the crank chamber. The method for controlling a fuel injection type two-cycle engine according to claim 1, wherein: