JP4362675B2 - Ignition system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition system that enables retreat travel when an abnormality occurs.
[0002]
[Prior art]
In a conventional general ignition system, a current (primary current) is supplied from a DC power source (battery) to the primary winding of the ignition coil, and this primary current is interrupted for each ignition, and a high voltage is applied to the secondary winding of the ignition coil. By generating a voltage and applying this high voltage to the spark plug to generate a spark discharge, the air-fuel mixture in the cylinder of the engine is burned. In recent years, in order to improve combustibility, there has been one in which multiple ignition is performed in which a spark discharge is continuously generated many times during one combustion stroke. In order to stably generate this multiple ignition, it is necessary to increase the energy supplied to the primary side of the ignition coil, and as in the prior art, simply applying the battery voltage directly to the primary side of the ignition coil The supplied energy does not increase, and multiple ignition may become unstable.
[0003]
Therefore, the energy supplied from the battery is accumulated in the energy coil, and the energy is supplied to the ignition driving capacitor provided in the primary circuit of the ignition coil for each ignition, and the charging energy of this capacitor is stored in the ignition coil. A system for supplying to the primary side is considered.
[0004]
[Problems to be solved by the invention]
By the way, if the power supply system of the ignition system fails due to disconnection or the like, and the energy cannot be supplied to the primary side of the ignition coil, the ignition stops immediately and the engine stops, and the vehicle is moved to a repair shop or a safe place. It cannot be evacuated.
[0005]
Therefore, in addition to the normal power supply circuit that supplies the energy supplied from the battery to the primary circuit of the ignition coil via the energy coil, the energy from the battery is supplied to the primary circuit of the ignition coil when the ignition is abnormal. An emergency power supply circuit that supplies power directly from the battery when the abnormality occurs and supplies the energy from the battery directly to the primary circuit of the ignition coil by the abnormal power supply circuit. Is considered.
[0006]
However, in this retreat travel system, even during retreat travel (ignition abnormality), the same energization time signal is used as in normal operation, and the energization time for passing the primary current of the ignition coil is the same as in normal operation. There is a possibility that the ignition energy will be insufficient and the combustibility will deteriorate, or the temperature of some parts will rise abnormally and the parts may fail, and the evacuation traveling system may not function normally.
[0007]
The present invention has been made in consideration of such circumstances. Therefore, the object of the present invention is to satisfy the ignition performance and the component temperature conditions required for evacuation traveling, and to improve the reliability of the evacuation traveling system. It is to provide an ignition system.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an ignition system according to claim 1 of the present invention includes a normal-time power supply circuit that supplies energy supplied from a DC power source to a primary circuit of the ignition coil via an energy coil. An abnormal power supply circuit is provided to directly supply the energy from the DC power source to the primary circuit of the ignition coil when the ignition is abnormal. The ignition monitor means monitors whether the ignition is abnormal and detects the ignition abnormality. When an abnormality occurs, the power supply circuit at the time of abnormality supplies energy directly from the DC power source to a circuit on the primary side of the ignition coil, and the energization time signal at the time of ignition abnormality (at the time of evacuation travel) by the ignition control circuit The evacuation travel is performed by switching to. In this way, during retreat travel, the energization time of the primary current of the ignition coil can be switched to an appropriate energization time that satisfies the ignition performance and component temperature conditions required for retreat travel. It is possible to satisfy the ignition performance and the part temperature condition that are sometimes required, to prevent the deterioration of combustibility during the retreat travel and the abnormal rise of the part temperature, and to improve the reliability of the retreat travel system.
[0009]
In this case, the pulse width (energization time) of the energization time signal during evacuation travel may be a fixed value set in advance to simplify the calculation process. Or you may make it set according to the voltage of DC power supply. In other words, the higher the engine speed, the higher the component temperature, the shorter the time range suitable for the ignition system, and the lower the DC power supply voltage, the lower the applied voltage to the primary side of the ignition coil. The time width suitable for the performance of the ignition coil becomes longer. Therefore, if the pulse width of the energization time signal during abnormalities (during evacuation) is set according to the engine speed and DC power supply voltage, the ignition is always performed without being affected by the engine speed or DC power supply voltage. It is possible to set the energization time so as to satisfy the performance and component temperature conditions, and the reliability of the evacuation traveling system can be further improved.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
First, a schematic configuration of the entire ignition system will be described with reference to FIGS. 1 and 2. The ignition coil 11 is provided for each cylinder of the engine, and generates a spark discharge by applying a high voltage generated by the secondary winding 11b of the ignition coil 11 of each cylinder to the ignition plug 12 (see FIG. 2) of each cylinder. By doing so, the air-fuel mixture in each cylinder is burned. An ignition drive device 14 having an energy coil 13 is connected to the primary winding 11 a of the ignition coil 11, and an engine control circuit (hereinafter abbreviated as “ECU”) 15 is connected to the ignition drive device 14. . The ECU 15 is mainly composed of a microcomputer, takes in output signals of various sensors for detecting engine operating parameters such as engine speed and intake air amount, and performs ignition control and fuel injection control according to the engine operating state. A positive terminal of a battery 16 that is a DC power source of the vehicle is connected to a power source terminal of the ignition driving device 14.
[0012]
Next, the circuit configuration of the ignition drive device 14 will be described with reference to FIG. A normal power supply circuit 17 and an abnormal power supply circuit 18 connected to the plus terminal of the battery 16 are provided in parallel. The normal power supply circuit 17 accumulates energy supplied from the battery 16 in the energy coil 13 when the ignition system is normal, and the energy is supplied to the primary side circuit of the ignition coil 11 for each ignition. The charging energy of the capacitor 19 is supplied to the primary winding 11a of the ignition coil 11. The operation of the normal power supply circuit 17 is controlled by the first switching element 20. The normal power supply circuit 17 is provided with two diodes 21 and 22 for regulating the direction of current flow.
[0013]
On the other hand, the abnormal power supply circuit 18 is constituted by a series circuit of the second switching element 23 and the diode 24. When an ignition abnormality occurs, the second switching element 23 is turned on to Energy is directly supplied to the primary winding 11a of the ignition coil 11. The second switching element 23 may be omitted and only the diode 24 may be configured. Alternatively, the abnormal power supply circuit 18 may be connected in parallel with only the energy coil 13.
[0014]
A switching element 25 for driving the ignition and a primary current detection resistor 26 are connected in series between the primary winding 11a of the ignition coil 11 and the ground terminal, and the switching element 25 is turned on for each ignition. .
[0015]
The first switching element 20, the second switching element 23, and the ignition driving switching element 25 described above are driven by a drive circuit 27, respectively. The drive circuit 27 receives an energization time signal IGt from the ECU 15 for each ignition, and further receives an ignition abnormality signal IGf when an ignition abnormality occurs. When the energization time signal IGt is input, the drive circuit 27 maintains the ignition drive switching element 25 in the ON state for a time corresponding to the pulse width of the energization time signal IGt, and the primary winding of the ignition coil 11. The primary current continues to flow through 11a.
[0016]
When the primary current flows through the primary current detection resistor 26, a voltage corresponding to the primary current is generated between both ends of the primary current detection resistor 26, and this voltage is taken into the ECU 15 as an ignition monitor signal. The ECU 15 monitors whether or not an ignition abnormality has occurred depending on whether or not the ignition monitor signal is equal to or lower than the abnormality determination voltage (see FIG. 3). When the ignition abnormality has occurred, the ECU 15 generates an ignition abnormality signal IGf. Output to the drive circuit 27. Therefore, the ECU 15 has a function as an ignition monitor means in addition to the function as an ignition control circuit in the claims.
[0017]
As shown in FIG. 3, when the ignition spark is normally generated, the ignition monitor signal exceeds the abnormality determination voltage every ignition and is determined to be normal, and the ignition abnormality signal IGf is not output from the ECU 15 (ignition abnormality) The signal IGf is maintained at a low level). In this case, the second switching element 23 in the abnormal power supply circuit 18 is maintained in the off state, and the energy supplied from the battery 16 is supplied to the primary circuit of the ignition coil 11 through the normal power supply circuit 17. Is done. An energization time signal IGt is input from the ECU 15 to the drive circuit 27 for each ignition, and each time the ignition drive switching element 25 is maintained in the ON state for a time corresponding to the pulse width T1 of the energization time signal IGt. A primary current flows through the primary winding 11 a of the coil 11.
[0018]
During the ON time of the ignition driving switching element 25, the first switching element 20 in the normal power supply circuit 17 is maintained in the OFF state, and the energy accumulated in the energy coil 13 is transferred to the ignition driving capacitor 19. Supplied. Thereafter, when the ignition drive switching element 25 is turned off, the first switching element 20 is turned on, and the energy supplied from the battery 16 is accumulated in the energy coil 13. Thereafter, the above-described operation is repeated several times for each ignition.
[0019]
On the other hand, when an ignition abnormality occurs, the ignition monitor signal becomes equal to or less than the abnormality determination voltage, and it is determined that the ignition is abnormal, and an ignition abnormality signal IGf (high level signal) is output from the ECU 15 to the drive circuit 27. In this case, the second switching element 23 in the abnormal power supply circuit 18 is turned on, and the energy from the battery 16 is directly supplied to the primary winding 11a of the ignition coil 11. At this time, the ECU 15 outputs the energization time signal IGt to the drive circuit 27 for each ignition even when the ignition is abnormal in order to enable the retreat travel, but the energization time signal IGt when the ignition is abnormal has a normal pulse width T2. Is switched to a signal different from the pulse width T1 of the current-carrying time signal IGt, and the ignition drive switching element 25 is kept on for a time corresponding to the pulse width T2 of the current-carrying time signal IGt. The primary current continues to flow through the primary winding 11a.
[0020]
In this case, the pulse width T2 (energization time) of the energization time signal IGt at the time of ignition abnormality (during retreat travel) may be a fixed value set in advance for simplification of the arithmetic processing. Alternatively, it may be set according to the voltage of the battery 16. For example, the pulse width T2 of the energization time signal IGt may be shortened as the engine speed increases, or the pulse width T2 of the energization time signal IGt may be increased as the voltage of the battery 16 decreases. In this way, it is possible to always set the energization time so as to satisfy the ignition performance and the component temperature condition without being affected by the engine speed and the voltage of the battery 16.
[0021]
In the present embodiment described above, when the ignition is abnormal (during evacuation travel), the energization time of the primary current of the ignition coil 11 is set to an appropriate energization time that satisfies the ignition performance and component temperature conditions required for evacuation travel. Therefore, it is possible to satisfy the ignition performance and component temperature conditions required during evacuation travel, prevent deterioration of combustibility during evacuation travel and abnormal rise in component temperature, and Reliability can be improved.
[0022]
The time width of multiple ignition may be controlled by the pulse width (energization time) of the energization time signal.
In the present embodiment, the primary current of the ignition coil 11 is detected to monitor the ignition abnormality, but the ionic current generated in the cylinder during combustion may be detected to monitor the ignition abnormality. The method for monitoring ignition abnormality may be changed as appropriate. The change (switching) of the energization time signal may be performed in the drive circuit.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an ignition system showing an embodiment of the present invention. FIG. 2 is an electric circuit diagram of the ignition system. FIG. 3 is a time chart showing signal waveforms of respective parts of the ignition system.
DESCRIPTION OF SYMBOLS 11 ... Ignition coil, 12 ... Ignition plug, 13 ... Energy coil, 14 ... Ignition drive device, 15 ... Engine control circuit (ignition control circuit, ignition monitoring means), 16 ... Battery (DC power supply), 17 ... Power supply at normal time Circuit: 18 ... Power supply circuit in case of abnormality, 19 ... Capacitor for ignition driving, 20 ... First switching element, 21, 22 ... Diode, 23 ... Second switching element, 24 ... Diode, 25 ... For ignition driving Switching element 26... Primary current detection resistor (ignition monitoring means) 27.

Claims (2)

An ignition coil that generates a spark discharge by applying a high voltage to the spark plug for each ignition;
A drive circuit that drives a swing element that turns on and off a primary current of the ignition coil;
An ignition control circuit for outputting an energization time signal for controlling an energization time for flowing the primary current to the drive circuit;
A normal-time power supply circuit for storing energy supplied from a DC power supply in an energy coil and supplying the energy to a primary circuit of the ignition coil for each ignition;
An abnormality power supply circuit that directly supplies energy from the DC power source to the primary circuit of the ignition coil when an ignition abnormality occurs;
Ignition monitoring means for monitoring whether or not an ignition abnormality has occurred,
The ignition control circuit directly supplies energy from the DC power source to the primary circuit of the ignition coil by the power supply circuit at the time of abnormality when the ignition monitor means detects an ignition abnormality, and the energization time signal Is switched to an energization time signal at the time of abnormal ignition. 2. The ignition system according to claim 1, wherein the ignition control circuit sets a pulse width of an energization time signal when the ignition is abnormal in accordance with an engine speed and / or a voltage of the DC power supply.

Images