JP2543708Y2 - Ignition timing control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ignition timing control device for an internal combustion engine.

[Conventional technology]

Usually, in an internal combustion engine, the ignition timing is set such that the engine output rises satisfactorily in response to an accelerator pedal depression operation. However, when the vehicle is moved backward, the vehicle is driven while looking back, so that the driving posture is deteriorated, and it is difficult to perform a delicate accelerator operation. Therefore, if the rise of the engine output torque is made good for the accelerator pedal depressing operation when the vehicle retreats as well as when the vehicle is moving forward, the vehicle will suddenly start or suddenly slow, and unless you use considerable nerves No.

Therefore, there is known an ignition timing control device that retards the ignition timing regardless of the engine load to lower the engine output when the vehicle moves backward (see Japanese Patent Application Laid-Open No. 61-129333).

[Problems to be solved by the invention]

However, the difficulty of adjusting the vehicle speed when reversing the vehicle is that the vehicle speed rises rapidly when the accelerator pedal is slightly depressed, whereas the vehicle speed is sufficiently increased when the accelerator pedal is depressed considerably. If the vehicle does not rise, good driving performance cannot be obtained when the vehicle retreats. Therefore, when the ignition timing is retarded at the time of reversing the vehicle regardless of the operating state of the engine as in the above-described ignition timing control device, the vehicle speed does not sufficiently increase even if the accelerator pedal is depressed considerably, and thus good vehicle driving performance is obtained. There is a problem that can not be secured. Further, when the ignition timing is retarded during the high-load operation of the engine, the exhaust gas temperature rises considerably. As a result, when the exhaust manifold, the exhaust pipe, and the catalyst are provided, there is a problem that the catalyst is thermally degraded.

[Means for solving the problem]

In order to solve the above problems, according to the present invention, a reverse position detecting means A for detecting that the transmission 18 is at the reverse position and an engine load are detected as shown in the configuration diagram of the present invention in FIG. When the engine load detecting means B and the transmission 18 are in the reverse position and the engine load is lower than a predetermined set load, the ignition timing is retarded, and the retard amount at this time increases as the engine load decreases. And ignition timing control means C that performs the control.

[Action]

During the reverse operation of the vehicle, the ignition timing is retarded only when the engine load is equal to or less than the set load, and the retard amount at this time is increased as the engine load is lower.

〔Example〕

Referring to FIG. 2, 1 is an engine body, 2 is a piston,
Reference numeral 3 denotes a cylinder head, 4 denotes a combustion chamber, 5 denotes a spark plug, 6 denotes an intake valve, 7 denotes an intake port, 8 denotes an exhaust valve, 9 denotes an exhaust port, and the intake port 7 passes through a corresponding branch pipe 10. Connected to surge tank 11. A fuel injection valve 12 is attached to each branch pipe 10, and fuel is injected from the fuel injection valve 12 into the corresponding intake port 7. The surge tank 11 is connected to an air cleaner (not shown) via an intake duct 13 and an air flow meter 14, and a throttle valve 15 is arranged in the intake duct 13. On the other hand, the exhaust port 9 is connected to an exhaust manifold 16, and an oxygen concentration detector 17 is arranged in the exhaust manifold 16. The fuel injection valve 12 and the ignition plug 5 are connected to the electronic control unit 30, and the injection timing from the fuel injection valve 12 and the ignition timing by the ignition plug 5 are controlled based on the output signal of the electronic control unit 30.

The electronic control unit 30 is composed of a digital computer, and a ROM (read only memory) 32, a RAM (random access memory) 33, a CPU (microprocessor) 34, an input port 35 connected to each other by a bidirectional bus 31.
And an output port 36. The air flow meter 14 generates an output voltage proportional to the amount of intake air, and this output voltage is input to an input port 35 via an AD converter 37. The oxygen concentration detector 17 generates an output voltage of about 0.1 volt when the mixture supplied to the engine cylinder is lean, and generates an output voltage of about 0.1 volt when the mixture supplied to the engine cylinder is rich.
Generates an output voltage on the order of volts. This oxygen concentration detector
The output voltage of 17 is input to the input port 35 via the AD converter 38. The transmission 18 is provided with a reverse position sensor 19 for detecting that the shift position of the transmission 18 is at the reverse position, and an output signal of the reverse position sensor 19 is input to the input port 35. A water temperature sensor 20 that generates an output voltage proportional to the engine cooling water temperature is attached to the engine body 1, and the output voltage of the water temperature sensor 20 is input to an input port 35 via an AD converter 39. Top dead center detection sensor 21 is 18
An output pulse is generated at every 0 crank angle, the crank angle sensor 22 generates an output pulse at every 30 crank angles, and the output pulses of the top dead center detection sensor 21 and the crank angle sensor 22 are input to the input port 35. . Electronic control unit
Within 30, the top dead center detection sensor 21 and the crank angle sensor 22
The current crank angle is calculated from the output pulse of, and the engine speed is calculated from the output pulse of the crank angle sensor 22.

On the other hand, the output port 36 is connected to the ignition plug 5 and the fuel injection valve 12 via the corresponding drive circuits 40 and 41.

Figure 3 (A) of the solid line L is transmission 18 reference ignition timing when the shift position is the engine speed N is constant when in the advanced position of theta _b and the engine load Q / N (intake air amount Q / 3 shows the relationship with the engine speed N). Warm-up after completion of the reference ignition timing theta _b is as ignition timing theta next, thus the engine load as can be seen from FIG. 3 (A) is in this case Q / N
Becomes smaller, the ignition timing θ is advanced.

Meanwhile, the theta _r in FIG. 3 (A) shows the ignition timing retard quantity after the completion of warming up when the shift position of the transmission 18 is in the retracted position, the ignition timing in this case theta is by a broken line M Is shown. This dashed line M is substantially equal to the ignition timing θ at the time of full load operation after the completion of warm-up. Therefore, the engine load Q / N is set at a predetermined load after the completion of warm-up when the shift position of the transmission 18 is at the reverse position. When (Q / N) is smaller than _{0, the} ignition timing θ is retarded to the ignition timing M at the time of full load operation after completion of warm-up. Therefore retard amount theta _r at this time, as shown in FIG. 3 (B) increases as the engine load Q / N becomes smaller. FIG. 3 (B) shows a case where the engine speed N is constant, and the ignition timing M at the time of full load operation after the completion of warm-up is actually the engine speed N.
After all, the retard amount θ _r is a function of the engine load Q / N and the engine speed N. And the retard amount theta _r, the relationship between the engine load Q / N and engine speed N is stored in advance in the ROM32 in the form of a map as shown in FIG. 3 (C), the retard this map The quantity θ _r is calculated.

The solid line N in FIG. 3 (D) indicates the relationship between the ignition timing θ and the engine shaft torque after the completion of the warm-up. transmission
18 after shifting position warmed-up in the forward position of theta ignition timing as a reference ignition timing theta _b the shaft torque becomes maximum.
Theta with respect to the shift position is the ignition timing after completion of warming up theta is the reference ignition timing theta _b in a retracted position of the transmission 18 contrast _r
, And thus the shaft torque decreases. Engine load
Since Q / N becomes higher retardation amount theta _r increases lower the amount of decrease in the axial torque when the engine load Q / N becomes lower increases. Therefore, considering the relationship between the throttle valve opening and the shaft torque as shown in FIG. 3 (E) (the solid line indicates the case where the shift position of the transmission 18 is at the forward position, and the broken line indicates the position of the transmission 18 When the throttle valve opening is small and the engine load Q / N is small, the rise of the shaft torque is smaller when the vehicle retreats and the throttle valve opening is constant when the vehicle retreats when the engine load Q / N is small. If the opening degree is exceeded, the vehicle is not retarded even when the vehicle is moving backward, so that the shaft torque becomes the same even when the vehicle is moving forward or when the vehicle is moving backward. Therefore, when the vehicle retreats, especially when the accelerator pedal depression amount, which is difficult to adjust the speed, is small, the shaft torque is reduced, so that the vehicle speed becomes insensitive to the accelerator pedal depression operation, and thus the vehicle speed is rapidly increased. It doesn't slow down or slow down so you don't have to use much nerves to drive. On the other hand, if the amount of depression of the accelerator pedal is large, sufficient shaft torque is generated, so that the retreat speed of the vehicle is sufficiently high, so that good vehicle drivability can be secured.

When the transmission 18 is in the reverse position and the engine load Q / N is smaller than the set load (Q / N) ₀ , the ignition timing θ is changed to the ignition timing at the time of full load operation after the completion of warm-up. If the angle is further retarded than M, the shaft torque can be further reduced, but in this case, a misfire may occur. Therefore, in order to reduce the shaft torque as much as possible without causing a misfire, the ignition timing θ is retarded to the ignition timing M at the time of substantially full load operation after the completion of warm-up.

On the other hand, in FIG. 3 (A), a chain line R indicates the ignition timing θ before the completion of warm-up when the transmission position of the transmission 18 is at the forward position, and in FIG. 3 (D), a chain line S indicates the transmission 18 shows the shaft torque before the completion of warm-up when the shift position of No. 18 is in the forward position. Such prior warming up the shaft torque is advanced by theta _k ignition timing theta is the reference ignition timing theta _b to maximize. Meanwhile warmed up as indicated in but the shaft torque becomes only the advance side theta _k relative to the ignition timing theta is the reference ignition timing theta _b which maximizes FIG. 3 (D) thus before completion of warming up Ignition timing θ compared to the later (solid line N)
The amount of decrease in the shaft torque when the angle is retarded is small. Therefore, when the shift position of the transmission 18 becomes the reverse position before the warm-up is completed, the ignition timing θ is retarded by θ _{r with} respect to the chain line R in FIG. The shaft torque does not decrease so much even when the angle is delayed from the k point to the m point in D). If Seshimere this time theta _r only retarding the ignition timing theta with respect to the reference ignition timing theta _b whereas the shaft torque drops to approximately the same shaft torque and after the completion of warming up. Therefore, even if the ignition timing θ is advanced by θ _{k with} respect to the reference ignition timing θ _b before the warm-up is completed, as shown by the chain line R in FIG. When the position becomes the retreat position, the ignition timing θ is retarded to the ignition timing M at the time of substantially full load operation after the completion of warm-up. That is, regardless of the warm-up of the engine, when the shift position of the transmission 18 becomes the reverse position, if the engine load Q / N is lower than the set load (Q / N) ₀ , the ignition timing θ becomes The ignition timing is retarded to the ignition timing M during the substantially full load operation.

FIG. 4 shows a routine for calculating the ignition timing shown in FIG. 3 (A), and this routine is executed at every constant crank angle.

Basic ignition timing theta _b is calculated from the crank angle sensor 22 and the engine speed based on the output signal of the air flow meter 14 N and the engine load Q / N, first, at step 50 and reference to Figure 4. Next, at step 51, the water temperature sensor 20
Warm-up correction advance amount theta _k is calculated based on the output signal.
Next, at step 52, it is determined based on the output signal of the reverse position sensor 19 whether or not the shift position of the transmission 18 is at the reverse position. Shift position of the transmission 18 is an ignition timing theta is calculated by adding the warm-up correction advance amount theta _k to the basic ignition timing theta _b proceeds to step 53 when in the advanced position. Next, at step 56, the ignition timing θ is output.

On the other hand, the retard amount theta _r from the third map shown in Figure (C) is calculated, which is stored in the ROM32 proceeds to step 54 when the shift position of the transmission 18 is in the retracted position. Then the ignition timing theta is calculated by subtracting the amount of delay theta _r from step 55 in the reference ignition timing theta _b, then the routine proceeds to step 56. Therefore, at this time, it is understood that the ignition timing θ is retarded to the ignition timing M at the time of full load operation regardless of the engine cooling water temperature.

[Effect of the invention]

As the engine load decreases when the vehicle moves backward, the ignition timing retard amount is increased to increase the shaft torque reduction amount, so speed adjustment is particularly easy when the accelerator pedal depression amount, which is difficult to adjust, is small. Further, as the depression amount of the accelerator pedal increases, the reduction amount of the shaft torque is reduced, so that good vehicle drivability can be secured. Further, since the exhaust gas temperature can be kept low during high load operation, damage to the engine exhaust system can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is an overall view of an internal combustion engine,
FIG. 3 is a diagram for explaining the ignition timing control according to the present invention, and FIG. 4 is a flowchart for calculating the ignition timing. 5: spark plug, 18: transmission, 19: reverse position sensor.

Claims (1)

(57) [Scope of request for utility model registration] 1. A reverse position detecting means for detecting that the transmission is at a reverse position, an engine load detecting means for detecting an engine load, and a predetermined load at which the transmission is at a reverse position and the engine load is predetermined. An ignition timing control device for an internal combustion engine, comprising: ignition timing control means for delaying the ignition timing when the engine load is lower than the predetermined value and increasing the retard amount at this time as the engine load is lower.