JPS63285264A - Ignition control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To control heat generation of an ignition coil and consumption of a battery by changing turning on time for an ignition coil according to an engine load within the allowable turning on limit of the ignition coil. CONSTITUTION:A control part 1 detects the load state of an engine from the quotient Q/N of an engine intake quantity Q divided by the number of engine revolutions N. In addition to that, the primary target turning on time is previously stored in a memory at 8 lower part near an allowable turning on limiting line of an ignition coil 2, and the secondary target turning on time at the lower part separated from the above-mentioned limiting line. The residual time of a rotational period subtracted by the primary target turning on time and that subtracted by the secondary target turning on time are established as the nonturning on time of the ignition coil 2 in the case of a heavy and a light engine load respectively. Thus the target turning on time can be established so long as to make certain ignition possible in the case of the heavy engine load, and so shortest as required for igniting in the case of the light engine load.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an ignition control device for an internal combustion engine.

[Prior Art] In ignition control, it is necessary to optimally determine the timing to start ignition depending on the operating state of the engine, and it is also necessary to maintain the voltage generated by the ignition coil at an appropriate level to ensure fuel ignition. is important.

The voltage generated by the ignition coil is normally proportional to the time the ignition coil is energized until ignition starts, and when the engine load is large, such as when the vehicle is accelerating, the voltage generated by the ignition coil is lengthened to ensure a sufficiently high voltage. It is necessary to obtain voltage.

By the way, when accelerating suddenly from a low speed state, the engine speed rises rapidly and the engine rotation period rapidly shortens, so the time for energizing the ignition coil may become insufficient and the ignition performance may deteriorate. there were.

Therefore, for example, in Japanese Patent Application Laid-open No. 56-135754,
An ignition control method has been disclosed in which the acceleration state of an engine is detected by a pulse signal output according to the opening degree of a throttle valve, and the energization time to an ignition coil is increased each time the pulse signal is input.

[Problems to be Solved by the Invention] However, since the opening degree of the throttle valve and the engine speed do not necessarily match, the extended energization time exceeds the permissible energization limit of the ignition coil, causing the ignition coil to become overloaded. This may cause the problem of heat generation.

The present invention solves this problem, and is an internal combustion engine that reliably detects the load state of the engine and appropriately switches the energization time to the ignition coil according to the magnitude of the engine load within the permissible limit of energization of the ignition coil. The purpose is to provide an ignition control device.

[Means for Solving the Problems] As shown in FIG. 1, the ignition control device of the present invention includes means for detecting the load state of the engine, means for detecting the rotation period of the engine, and means for detecting the energization permission of the ignition coil. The first one is set to change in proportion to the rotation period above near the limit line.
storage means for pre-memorizing a second target energization time which is set to change in proportion to the rotation period below the energization permissible limit line; The magnitude is determined, and if the load is large, the time obtained by subtracting the first target energization time from the rotation period is set as the non-energization time of the ignition coil, and if the load is small, the second target energization time is set from the rotation period. a de-energizing time setting means that sets a time obtained by subtracting the target energizing time of the ignition coil as a de-energizing time of the ignition coil, and an energizing control that stops energizing the ignition coil for the set de-energizing time from the start of ignition of the ignition coil. It is equipped with the means.

[Effect] According to the ignition control device having the above configuration, when the engine load is large, a long target energization time is set close to the energization permissible limit line. Can be ignited. Furthermore, when the engine load is small, the shortest target energization time required for ignition is set below the energization permissible limit line, so unnecessary heat generation of the ignition coil and battery consumption can be prevented.

One example of a case where the engine load is large is when the vehicle is accelerating, and in this case, the engine rotation period rapidly shortens as the rotation increases. Therefore, in the ignition control device of the present invention, the time obtained by subtracting the target energization time from the rotation period is set as the non-energization time of the ignition coil, and the maximum energization time allowed in advance is secured. It is possible to prevent ignition failure during vehicle acceleration due to insufficient energization time.

[Example] FIG. 2 shows the hardware configuration of the ignition control device.

In the figure, a control section 1 includes an AD converter 11, an input buffer 12, a microcomputer 13, and an output buffer 14, and the output buffer 14 is connected to a power transistor 3 that turns on/off energization to the ignition coil 2.

The AD converter 11 includes sensors 41, 42, 4 for engine intake air amount, battery voltage VB, and cooling water temperature.
3 are connected, and these measured quantities are input into the computer 13 after being converted into digital data. input buffer 1
A rotation angle sensor 44 is connected to 2, and the sensor 44 emits a pulse signal 44a at a predetermined rotation angle of the crankshaft (for example, the piston top dead center position). The above input buffer 12
An idle switch 45 that detects engine idling when the throttle valve is fully closed and a neutral switch 46 that indicates the neutral position of the transmission are connected to.

FIG. 3 shows a flowchart of the processing program of the computer 13. In step 101, every time the pulse signal 44a from the rotation angle sensor 44 is input, the signal period T
Calculate INT. In step 102, the battery voltage V
B, and then divide the engine intake air amount data Q by the engine rotation speed N, which is the reciprocal of the signal period TINT, to obtain Q.
/N is obtained (step 103). This Q/N well represents the load condition of the engine.

Therefore, in step 104, the above Q/N is a constant value α
If it is larger, the engine load is determined to be large and step 105 is performed.
Otherwise, the engine load is determined to be small and the process proceeds to step 106. In steps 105 and 106, the first and second target energization times TON1 and TO are determined according to the following formulas, respectively.
Calculate N2.

I NT TON 1 =-+TVB+D・・・・・・(1) I
NT T ON 2 = -10T V B 10B...
(2) Here, A, B, C', and D are constants, and C<A
, BAD. TVB is a voltage correction term determined by the battery voltage, and is dependent on the primary current rise characteristics of the ignition coil.

FIG. 4 shows a graph of the above equations (1) and (2) with respect to the engine rotation speed N, which is the reciprocal of TINT. formula<
1) is indicated by a line X in the figure, which is located near and below the energization permissible limit line of the ignition coil 2. Formula (2)
is indicated by line y in the figure, and is located below and away from the line X in the low engine speed range.

That is, the target energization time TONI is set to the maximum value within a range that does not cause excessive heat generation in the ignition coil 2, and the target energization time TON2 is set to an extent that does not cause ignition failure during normal engine operation.

In step 107, the engine cooling water temperature is read, and in the subsequent step 108, it is determined from the idle switch signal whether or not it is idling, and the ignition start angle is selected from preset tables β and γ accordingly (step 109). .11o).

In step 111, the selected ignition start angle is converted into an ignition start time Ts. In step 112, the target energization time TONI or the target energization time TON2 is subtracted from the rotation period TINT, and the remaining time is set as the non-energization time TOFF, and the power transistor 3 is supplied with an energization signal 14a based on the pulse signal 44a of the rotation angle sensor 44. emits.

This will be explained with reference to FIG. After the ignition start time Ts has elapsed from the fall of the pulse signal 44a, the energization signal 14
Let a be rOFFJ. As a result, a high voltage appears on the secondary side of the ignition coil 2, and the fuel is ignited. Energization signal 1
4a is rOF during the above-mentioned non-energization time TOFF, which has already been calculated.
It is placed in the FJ state and then becomes the "ON" state.

When the engine rotation is approximately constant, successive rotation periods T
I NT hardly changes, and the energization time of the ignition coil is changed according to the magnitude of the engine load by the energization signal 14a. As mentioned above, when the engine load is large, this energization time is set close to the permissible energization limit of the ignition coil to enable reliable ignition without overheating the ignition coil, and when the engine load is small, It is set to the minimum time sufficient for ignition to prevent unnecessary heat generation of the ignition coil and battery consumption.

When the engine speed increases rapidly in a high engine load state, the rotation period TINT becomes gradually shorter, and the energization signal 14a is brought into the rOFFJ state at a predetermined time Ts after the fall of the pulse signal 44a. The "ON" state of the energization signal 14a becomes correspondingly shorter.

Here, the target energization time T in a high load state.

Since N1 is set to be sufficiently long, the ignition coil is energized for a sufficiently long time even by the energization signal 14a whose "ON" state is relatively short, and reliable ignition is possible.

In the above embodiment, one of the target energization times may be calculated by multiplying the other by a coefficient.

Further, the engine load state can also be detected by intake pipe pressure, a combination of engine speed and throttle opening, or shaft torque.

Further, the neutral state of the transmission in which the rotational speed change is the largest is determined by the level of the neutral switch 46,
The first target energization time may be selected when a high load state is detected in the neutral state, and the second target energization time may be selected at other times.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of the present invention, Fig. 2 is a block diagram of the ignition control device, Fig. 3 is a program flow chart, Fig. 4 is a graph of changes in target energization time, and Fig. 5 is a signal time chart. be. 1...Control unit 13...Microcomputer 2...Ignition coil 3...Power transistor 41...Engine intake air amount sensor 44...Rotation angle sensor

Claims (4)

[Claims] (1) means for detecting the load condition of the engine; means for detecting the rotation period of the engine; a second target energization time that is set to change in proportion to the rotation period below the energization permissible limit line; If the load is large, the time obtained by subtracting the first target energization time from the rotation period is set as the non-energization time of the ignition coil, and if the load is small, the first target energization time is set from the rotation period. a non-energizing time setting means for setting the time obtained by subtracting the target energizing time from step 2 as the non-energizing time of the ignition coil; and energizing for stopping energizing the ignition coil for the set non-energizing time from the start of ignition of the ignition coil. An ignition control device for an internal combustion engine, comprising a control means. (2) The ignition control device for an internal combustion engine according to claim 1, wherein the engine load state detection means is set to detect the load state based on the amount of intake air per unit rotation of the engine. (3) The ignition control device for an internal combustion engine according to claim 1, wherein the load state detection means is set to detect the load state based on the magnitude of the intake pipe pressure of the engine. (4) The internal combustion engine according to claim 1, wherein execution of the ignition coil de-energization time setting based on the first target energization time when the load is large is permitted when the transmission is in the neutral state. Ignition control device.