JPH0968068A - Fuel injection quantity control device for two-cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an accelerating feeling in a low-medium speed and medium high load operation area, cope with even a temporary large load, and facilitate starting. SOLUTION: A fuel injection quantity control device of a two-cycle engine is provided with a crank angle sensor 9 to function as an operation condition detecting means to detect an engine operation condition, a throttle opening sensor 27 and an ECU 18 to function as a fuel injection quantity control means to control a fuel injection quantity in a reference injection quantity according to an engine operation condition and also as a fuel injection quantity correcting means to correct the reference injection quantity with every prescribed cycle so that torque amplitude is generated in a prescribed operation area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control device for a two-cycle engine.

[0002]

2. Description of the Related Art A two-cycle engine is an engine that completes one cycle during one revolution of a crankshaft (one reciprocation of a piston, two strokes) and explodes every time. In contrast, when the same average torque is used, torque fluctuation is small and smooth torque characteristics can be obtained.

[0003]

However, as described above, since the engine explodes once per one revolution of the crankshaft, the torque per revolution of the engine in the case of the same average torque engine is smaller than that of the four-cycle engine. Therefore, for example, there is a problem that the engine is easily stopped in a low-speed rotation low-medium load operation range such as at the time of starting, and there is a problem that an acceleration feeling (a feeling of traction) is poor particularly in a low-medium speed and medium-high load range. There is also a problem that the engine is likely to be stopped even when a large load is temporarily generated, such as when riding on a stone or the like while climbing a hill in the same operating condition.

The present invention has been made in view of the above-mentioned conventional problems, and can improve the feeling of acceleration in a low / medium speed and medium / high load operation range, and can cope with a temporary large load. An object of the present invention is to provide a fuel injection amount control device for a two-cycle engine that is easy to start.

[0005]

According to a first aspect of the present invention, an operating state detecting means for detecting an engine operating state, and a fuel injection amount controlling means for controlling a fuel injection amount to a reference injection amount according to the engine operating state are provided. A fuel injection amount control device for a two-cycle engine, comprising: a fuel injection amount correction means for correcting the reference injection amount for each predetermined cycle so that a torque amplitude is generated in a predetermined operation range.

According to a second aspect of the present invention, in the first aspect, the operating state detecting means includes a rotational speed detecting means for detecting an engine rotational speed and an opening degree detecting means for detecting a throttle opening degree. It is characterized in that the fuel injection amount correction means corrects the fuel injection amount in the low to medium speed rotation and medium to high load operation range.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 11 are views for explaining a fuel injection amount control device for a two-cycle engine for a motorcycle according to an embodiment of the present invention, FIG. 1 is a configuration diagram of the two-cycle engine, and FIGS. Engine speed-load characteristic diagram showing the fuel injection amount control region, FIG. 4 is a characteristic diagram showing the fuel injection amount for each cycle, FIG. 5 is a flowchart diagram for explaining the operation of the control device, and FIG. FIG. 7 is a diagram showing a three-dimensional map showing the relationship between the number of fuel cells, the throttle opening, and the reference fuel injection amount. FIG. 7 is a characteristic diagram showing the relationship between engine speed and load. FIG. 9 is a characteristic diagram showing the relationship between engine cycle and torque, and FIGS. 10 and 11 are characteristic diagrams showing the relationship between throttle opening and torque.

FIG. 1 is a configuration diagram of a crankcase compression type two-cycle engine to which the present invention is applied. This engine 1
Is composed of a crankcase 2, a cylinder block 3 above it, and a cylinder head 4.

Cylinder bore 3 of the cylinder block 3
A piston 5 is slidably inserted and arranged in a, and is connected to a crankshaft 7 via a connecting rod 6. A ring gear 8 having a predetermined number of teeth is mounted on the crankshaft 7, and also serves as an engine speed sensor for detecting a rotational position of the ring gear 8 and measuring a crank angle and an engine speed. A crank angle sensor 9 is provided.

The cylinder head 4 has a combustion chamber pressure sensor 1 for detecting combustion pressure and temperature in the combustion chamber 10.
1, the temperature sensor 25 is installed, the combustion chamber 10
The combustion pressure information, the temperature information, and the engine speed signal N from the crank angle sensor 9 are sent to a control unit (ECU) 18 for controlling the engine operating state.

An ignition plug 26a is attached to the cylinder head 4, and an ignition timing signal a is supplied from the control device 18 to an ignition circuit 26 which supplies a high voltage to the ignition plug 26a. Reference numeral 12 is a cooling water jacket surrounding the combustion chamber 10 and the cylinder bore.

Exhaust port 3a of the cylinder block 3
An exhaust pipe 13 is connected to the exhaust pipe 13, and an exhaust pipe temperature sensor 17 is provided in the middle of the exhaust pipe 13.
The detection signal 7 is input to the control device 18.

Intake port 2 opening in the crankcase 2
An intake passage 14 is connected to a, and a reed valve 15 is arranged at the connection port. Further, a throttle body 22 having a throttle valve 21 is provided in the intake passage 14. An intake pipe pressure sensor 19 and an intake air temperature sensor 20 are mounted on the throttle body 22, and intake pipe pressure information and intake air temperature information are input to the control device 18.

The throttle valve 21 includes a wire 23.
Is connected to the throttle grip 24, and the throttle opening is adjusted by rotating the grip 24. The throttle opening is detected by the throttle opening sensor 27, and the throttle opening signal θ is input to the control device 18. Further, an intake air amount sensor (not shown) is provided in the intake passage 14, and intake air amount information is sent to the control device 18.

A scavenging port 28 is provided in the crankcase 2.
Is communicated with the inside of the cylinder bore 3a, and the scavenging port 28 is provided with a fuel injection valve 29 for injecting fuel into the cylinder bore 3a. The fuel injection valve 29 is controlled by the injection control signal b from the control device 18 so that the fuel injection timing and the fuel injection amount correspond to the operating state. The engine 1 is equipped with a clutch device and a transmission device (not shown), and the output of the crankshaft 7 is transmitted to the rear wheels through the clutch and the transmission device, and through a chain drive device (not shown).

Next, the fuel injection control by the controller 18 will be described. In this fuel injection control, first, an optimum reference fuel injection amount according to the engine operating condition determined by the engine speed N and the throttle opening θ (load) is calculated as engine speed−throttle opening−fuel injection amount. The fuel injection valve 29 is controlled so that the reference injection amount is obtained from the three-dimensional map.

On the other hand, as indicated by the shaded area A in FIG. 2, torque amplitude is generated in the operating range above the threshold value θ ₀ where the engine speed is low and medium speed and the engine load is medium and high. Therefore, as shown in FIG. 4, correction control is performed to reduce or increase the reference injection amount every predetermined cycle (for example, every one cycle). The fuel injection amount correction control is performed by controlling the opening time of the fuel injection valve 29.

Here, the operating range to which the above-mentioned fuel injection amount correction control is applied can be appropriately changed according to the application or characteristics of the engine. For example, the correction control is performed in the operating range shown by the hatched portion B in FIG. You may. In this example, the fuel correction control is performed even when there is no load when the rotation speed is equal to or lower than a predetermined value.
In this case, it is possible to prevent the engine from stopping at the start.

The fuel injection amount correction control will be described in more detail with reference to the flowchart of FIG. When the control starts, first, a variable (flag) I is set to 0, and the engine speed N from the crank angle sensor (rotation speed detection means) 9 and throttle opening sensor (opening detection means) 27 and throttle opening The degree θ is read as a factor representing the operating state (steps S1 and S2). The above variable I
Is a cycle number for determining the correction amount in the fuel injection amount correction control. When I = 0, the correction is not performed, and when I = I to N, the injection amount is corrected according to the cycle number. Controlled.

From the three-dimensional map of engine speed-throttle opening-reference fuel injection amount shown in FIG. 6, the reference fuel injection amount q ₀ is set according to the read engine speed N and throttle opening θ. (Step S3) Further, the threshold throttle openings θ _{1 to} θn are set according to the characteristic diagram of FIG. 7 (step S4).

Next, the correction amount of the fuel injection amount is set according to the result of comparison between the current throttle opening θ and the predetermined threshold value opening set above. Specifically, when θ is smaller than θ ₁ , the reference fuel injection amount q ₀ is directly used as the correction amount injection amount q ′, and the variable I is set to 0 (steps S5 to S7). ).

Then, the fuel supply time is set from the set fuel injection amount q ', and the fuel is injected from the fuel injection valve 29 (step S8). After that, if the stop condition such as turning off the ignition key is input, the engine control is stopped. If not input, the process returns to step S2 and the process is performed again (step S).
9).

In step S5, when the current throttle opening θ is equal to or larger than the set opening θ ₁ , the above θ is compared with θ ₂ (step S10).

When θ is smaller than θ ₂ , the cycle number indicated by the variable I is counted up to a predetermined variable N, and the correction amount Δq (I) of the fuel injection amount is set according to this cycle number. To be done. The control of the correction amount is performed by controlling the opening time of the fuel injection valve 29.

More specifically, if the variable I is 0, this I
Is set to 1 and the reference fuel injection amount q ₀ is injected from the fuel injection valve 29 (steps S11 to S11).
S13, S8).

In step S11, the variable I
Is not 0 and when I is determined to be 1 in step S14, the fuel injection amount corrected by the predetermined fuel amount Δq (1) from the set reference fuel injection amount q ₀ is the new fuel injection amount q. Is set as' (steps S14, S
15). Then, 1 is added to the variable I (step S13), the process proceeds to step S8, and the fuel is injected for the fuel supply time set by the fuel injection amount q '. The fuel correction amount (Δq (1) to Δ
q (n)) is set from a three-dimensional map of N engine speeds-throttle opening-fuel correction amount stored in the control device 18.

In step S13, the variable I
Is not 1 and when I is determined to be 2 in step 16, the fuel injection amount corrected by the predetermined fuel amount Δq (2) from the set reference fuel injection amount q ₀ is the new fuel injection amount q. ’(Steps S16, S1
7). Then, while 1 is added to the variable I,
In step S8, the fuel is injected for the fuel supply time set by the fuel injection amount q '.

Similarly, when the variable I is (N-1),
As the fuel injection amount q ′, a fuel injection amount corrected by a predetermined correction fuel amount Δq (N−1) from the reference fuel injection amount q ₀ is set as a new fuel injection amount q ′ (step S17, S18). Then, 1 is added to the variable I, the process proceeds to step S8, and the fuel injection amount q'is injected.

Finally, the variable I is 0 to (N-
When not 1), that is, when I is N, the fuel injection amount q
′ Is a predetermined corrected fuel amount Δ from the reference fuel injection amount q _0.
The fuel injection amount corrected by q (N) is set as a new fuel injection amount q '(step S20). Then, the variable I is set to 0 (step S2).
1), the process proceeds to step S8, and the fuel injection amount q
´ is jetted.

Here, when the above-mentioned θ is equal to or more than θ ₂ in the above-mentioned step S10, this θ is next compared with the predetermined threshold value opening θ ₃ set above (step S2).
2). When θ is smaller than θ ₃ , the fuel injection amount is set as in steps S11 to S21.

Further, in step S22, when θ is equal to or greater than θ ₃ , this θ is sequentially compared with the predetermined threshold value opening θ _{4 to} θn, and the fuel injection amount is set in the same manner as above. .

As described above, in this embodiment, the variable I is 0.
When the variable I is 1, the reference fuel amount is injected and this I is set to 1. When the variable I is 1, the reference fuel amount corrected fuel amount is injected and 1 is added to the variable I, and the variable I is N.
Since the correction of the above fuel amount was performed until
In the non-corrected load region shown in FIGS. 8 (a) and 8 (b), as shown in FIGS. 9 (a) and 9 (b), the same amount of torque is generated for each engine cycle. In the above-mentioned corrected load regions shown in (c), (d) and (e), as shown in FIGS. 9 (c), (d) and (e), torques T1 and T2 having different magnitudes for each engine cycle are shown. Is generated and torque amplitude is generated.

As a result, it is possible to improve the sensation of traction, and thus the feeling of acceleration, in a low-medium speed, medium-high load operation range. Further, it is possible to avoid an engine stop when the load temporarily increases, such as when riding on a stone or the like while climbing a slope. In particular, a motorcycle for running on a rough land is used to run up a stone or a rock at a low speed, and a large torque is required at the moment of running up. By mounting the ignition timing control device of the present embodiment, it is possible to run up a higher head or run through a wasteland with larger stones. Further, this is effective not only for motorcycles but also for other transportation equipment that requires mobility, such as small snow vehicles that run through steep hills and small vessels that sail over waves.
Further, it is also effective in driving a general-purpose engine that has a sudden load change.

When the fuel injection amount correction control is started, the torque is reduced from T1 to T2 every cycle as shown in FIGS. 9 (c), (d) and (e). The average torque also decreases to T3, and as indicated by the solid line L1 in FIG. 10, the engine torque temporarily decreases when the throttle opening is θ ₀ . Note that FIG.
A broken line L0 indicates the characteristic when the fuel injection amount correction control is not performed.

This temporary decrease in engine torque is easily corrected by the driver slightly opening the throttle grip, but the following fuel injection amount correction control can be adopted as a method for avoiding this torque decrease. That is, when the throttle opening θ exceeds the threshold opening θ ₀ , a method of controlling the fuel correction amount Δq to be smaller as the opening θ is smaller is effective. As a result, it is possible to avoid a sudden decrease in torque as indicated by the solid line L2 in FIG.

[0036]

As described above, according to the invention of claim 1,
According to the fuel injection amount control device of the cycle engine, the fuel injection amount is corrected every predetermined cycle in the specific operation range, so that the torque of the cycle changes from the cycle of the reference fuel injection amount, and the torque is thereby changed. Amplitude is generated, and as a result, there is an effect that the tactile traction can be improved.

According to the second aspect of the present invention, the fuel injection amount is corrected every predetermined cycle in the low / medium speed rotation and medium / high load operating range, so that the torque feeling in the operating range can be improved, and the temporary operation can be improved. There is an effect that can be dealt with even when a load is applied.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a two-cycle engine including a fuel injection amount control device according to an embodiment of the present invention.

FIG. 2 is an engine speed-load characteristic diagram showing a fuel injection amount correction control region of the engine of the above embodiment.

FIG. 3 is an engine speed-load characteristic diagram showing a fuel injection amount correction control region of the engine of the above embodiment.

FIG. 4 is a characteristic diagram showing a fuel injection amount for each cycle of the engine of the embodiment.

FIG. 5 is a flow chart diagram for explaining a control operation of the engine of the embodiment.

FIG. 6 is a three-dimensional map diagram showing the relationship between the engine speed, the throttle opening, and the reference fuel injection amount of the engine of the above embodiment.

FIG. 7 is a characteristic diagram showing a relationship between an engine speed and a threshold opening of the engine of the embodiment.

FIG. 8 is a characteristic diagram showing a relationship between load and torque of the engine of the embodiment.

FIG. 9 is a characteristic diagram showing torque for each cycle of the engine of the embodiment.

FIG. 10 is a characteristic diagram showing a relationship between throttle opening and torque of the engine of the above embodiment.

FIG. 11 is a characteristic diagram showing a relationship between throttle opening and torque of the engine of the embodiment.

[Explanation of symbols]

9 crank angle sensor (operating state detecting means, rotational speed detecting means) 18 ECU (fuel injection amount control means, fuel injection amount correcting means, fuel injection amount control device) 27 throttle opening sensor (operating state detecting means, opening detection) means)

Claims (2)

[Claims] 1. An operating state detecting means for detecting an engine operating state, a fuel injection amount controlling means for controlling a fuel injection amount to a reference injection amount according to an engine operating state, and a torque amplitude in a predetermined operating range. A fuel injection amount control device for a two-cycle engine, comprising: a fuel injection amount correction means for correcting the reference injection amount for each predetermined cycle. 2. The operation state detection means according to claim 1, further comprising a rotation speed detection means for detecting an engine rotation speed and an opening degree detection means for detecting a throttle opening degree.
A fuel injection amount control device for a two-cycle engine, wherein the fuel injection amount correction means performs the fuel injection amount correction in a low to medium speed rotation and medium to high load operation range.