JPH0410382Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an ignition timing control device for an engine.

[Technical background of the invention and its problems] As is well known, engine startability can be improved by advancing the ignition timing when the engine starts up.

Further, the overspeed phenomenon when the engine is under no load can be controlled by delaying the ignition timing.

Advance control for advancing or retarding engine ignition timing in this manner can be performed using the centrifugal ignition advance method in the prior art, but cannot be performed using the transistor ignition method.

Moreover, with the centrifugal ignition advance method, it is not possible to appropriately set the phase advance start rotation speed in the low engine speed region and the slow phase rotation speed in the high speed region.

Further, a microprocessor-controlled ignition timing control device equipped with a CPU and configured to connect the CPU and an ignition unit via a system controller has been put into practical use.

In the case of this type of microprocessor-controlled ignition timing control device, it is possible to perform advance control in the same way as an ignition timing control device using a centrifugal ignition advance method, and it is also possible to control the advance angle in the low speed region. It is possible to variably set the number and the slow phase rotation speed in the high speed region as appropriate.

However, since a system configuration equipped with a CPU has complicated components, it is possible to perform advance/lag lead angle control without adopting a system configuration equipped with this CPU, and also to control the lead angle. There was a desire to apply an ignition timing control device to an engine that can be set variably as appropriate.

[Purpose of the invention] The present invention was made in view of the above, and its purpose is to be able to control the lead angle of advance and lag all at once using a digital circuit configuration that does not require a CPU, and to control the lead angle. The purpose is to enable variable settings as appropriate.

[Summary of the invention] In order to achieve the above object, the present invention includes: two rotation detection circuits that emit detection signals of different pulse trains at repetition periods corresponding to the engine rotation speed; A logic circuit that performs a logical operation and generates a data pulse group indicating the rotational speed of the engine from the result of the operation; A rotational speed detection circuit that receives the generated data pulse group and detects the rotational speed of the engine; If the engine rotational speed is in a region lower than a constant speed, the ignition timing of the engine can be given a phase advance characteristic, and if it is in a region higher than a constant speed, it can be given a slow phase characteristic. It is characterized by having a setting circuit that can appropriately set.

[Embodiments of the invention] Hereinafter, embodiments of the invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram of an ignition system including an ignition timing control device to which the present invention is applied.

In the figure, 1 is an ignition timing control device, and this ignition timing control device 1 includes a rotation detection circuit 2, a rotation detection circuit 3, a logic circuit 4, a low-frequency oscillator 5, a first shift register 6, a second shift register 6, and a rotation detection circuit 3. It includes a shift register 7, a magnitude comparator 8, a decorator 9, etc.

Reference numeral 11 denotes an ignition unit, and the ignition unit 11 includes an ignition plug 12, an ignition coil 13, a transistor 14, a transistor 15, and the like.

21 is a power supply device, and this power supply device 21 includes a generator 22, a rectifier circuit 23, a smoothing circuit 24,
It includes a constant voltage circuit 25, a voltage dividing circuit 26, and the like.

In the ignition timing control device 1, the rotation detection circuit 2
and 3 are each equipped with detection couplers A and B, and detection couplers A and B are shifted by 180 degrees and placed at respective positions on each assumed line forming a concentric circle, and detection coupler A and the detection coupler B line are provided with two slits A ₁ , A ₂ and two slits B ₁ , B ₂ as shown in FIG. A disk 40 is arranged. In addition, the rotating disk 4
0 is rotated to the right in the illustration. Also, slit
The rear end of B ₂ should match the upper fulcrum of the engine.

Now, when the rotating disk 40 is rotated in synchronization with the engine, the output signals of each part of the ignition timing control device 1 are as shown in the time chart in FIG. 3.

The rotation detection circuit 2 emits a pulse train detection signal A from the slits A ₁ and A ₂ at a repetition period corresponding to the engine rotation speed, and the rotation detection circuit 3
Similarly, a pulse train detection signal B is generated by the slits B ₁ and B ₂ at a repetition period corresponding to the engine speed.

The logic circuit 4 receives the detection signals A and B and performs a logical operation, and from the result of the operation, outputs a signal U and a signal V as data pulse group signals indicating the rotational speed of the engine.
Furthermore, a signal X and a signal T are respectively generated as data pulse group signals indicating the angle from the ignition possible starting point to the top dead center.

However, in each of these signals, the signal U is generated at a timing when one slit _A component of the signal A and _one slit B component of the signal B are synchronized.

The signal V is generated with a pulse width corresponding to the time width τ ₁ from the rise of the slit A ₁ component to the rise of the slit A ₂ in the signal A.

The signal X is generated with a pulse width corresponding to the time width τ ₂ from the rise to the fall of the _two components of the slit B in the signal B.

Signal T is a logical negation pulse that becomes "L" level when signal X is "H" level.

Signal U is a logical negation pulse that goes to "L" level when signal V is at "H" level.

Of the data pulses generated in this way, the signal U and the signal V are sent to the first shift register 6, and the signal X and the signal T are sent to the second shift register 7.

The first shift register 6 receives the signal U at the R terminal to be set to an initial state, receives the signal V at the CE terminal, and is chip-enabled while the signal V is at a high level and receives the clock signal from the low-period oscillator 8. When the signal V becomes low level, the time width τ ₁
The count value corresponding to is latched. Therefore, in response to an increase or decrease in the time width τ ₁ in signal A,
The longer the time width τ ₁ is, the slower the engine rotation speed is obtained, and the shorter the time width τ ₁ is, the faster the engine rotation speed is obtained.

The second shift register 7 receives the signal X at the CE terminal and is chip-enabled while the signal ₂
Count until it corresponds to the pulse width τ ₂ of the component. Therefore, the setting range of the engine's ignition timing can be indicated by counting.

The count contents of the first shift register 6 and the second shift register 7 are then sent to the magnitude comparator 8.

On the other hand, the magnitude comparator 8 converts the clock signal of the fixed-period oscillator 5 into the second shift register starting from the rising edge of the signal X in each case of the engine rotational speed obtained from the counting result of the first register 6. 7 to set the number of ignition pulses to be sent to the ignition unit 11.
The output of the first shift register 6 is programmed in hardware by the decoder 9 in accordance with the setting contents, and is latched in the channel, and bit-matched with the output of the second shift register 7.

On the other hand, the ignition unit 11 receives the ignition pulse from the magnitude comparator 8 to the transistor 1.
When added to the base of 4, transistor 15 becomes
As a result, a back electromotive force is generated on the primary side of the ignition coil 13, and the voltage on the secondary side thereof is increased, so that a spark is generated in the ignition plug 12.

Therefore, in the magnitude comparator 8, when the count result of the first shift register 6 indicates a low speed region, the engine ignition timing has a phase advance characteristic, and when it indicates a high speed region, the engine ignition timing has a phase delay characteristic. In addition, the ignition timing in each of the low speed and high speed ranges can be appropriately set based on the count value of the second shift register 7.

In the power supply device 21, the AC output of the generator 22 is exchanged to DC by the rectifier circuit 33, the output is shaped by the smoothing circuit 24, and the DC constant voltage is obtained by the constant voltage circuit 25. Then, this DC constant voltage power is supplied as it is to the ignition unit 11, and is also divided into voltages and used as a power source for each part of the ignition timing control device 1.

[Effects of the invention] As explained above, the engine ignition timing control device to which the invention is applied can perform advance/lag advance angle control all at once using a digital circuit configuration that does not require a CPU. , the lead angle can be variably set as appropriate.

[Brief explanation of the drawing]

Figure 1 is a circuit configuration diagram of an ignition system including an ignition timing control device for an engine to which the present invention is applied, Figure 2 is a configuration diagram of a rotating disk that forms the main parts of two rotation detection circuits, and Figure 3 is FIG. 1 is a time chart schematically showing the signals of each main part of the ignition system. DESCRIPTION OF SYMBOLS 1... Ignition timing control device, 2... Rotation detection circuit, 3... Rotation detection circuit, 4... Logic circuit, 5...
... Fixed period oscillator, 6... First shift register,
7... Second shift register, 8... Magnitude comparator, 11... Ignition unit, 1
2... Spark plug, 13... Ignition coil, 14... Transistor, 15... Transistor, 21... Power supply device, 22... Generator, 23...
... Rectifier circuit, 24 ... Smoothing circuit, 25 ... Constant voltage circuit, 26 ... Voltage dividing circuit, 40 ... Rotating disk.

Claims (1)

[Claims for Utility Model Registration] Two rotation detection circuits that emit detection signals of different pulse trains at a repetition period corresponding to the engine rotation speed, and a logical operation performed on each detection signal from these two rotation detection circuits, and an arithmetic circuit that respectively creates a data pulse group indicating the rotational speed of the engine and a data pulse group indicating the angle from the ignition possible reference point to top dead center from the calculation results; A first shift register that indicates by counting whether the rotational speed of the engine corresponds to a lower speed region or a higher speed region than a constant speed, and a data pulse group that indicates the angle from the ignition possible base point to the top dead center; a second shift register that indicates a setting range of the engine's ignition timing by counting; and a second shift register that provides a phase advance characteristic to the engine's ignition timing when the counting result of the first shift register indicates a low speed range, and indicates a high speed range. At the same time, the ignition timing of the engine can have a delayed phase characteristic.
An ignition timing control device for an engine, comprising a magnitude comparator that can appropriately set the ignition timing in each of low speed and high speed regions based on the count value of the second shift register.