JPH0532772U - Ignition timing control device for two-cycle internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to perform optimum ignition timing control in accordance with the ignition timing required for each cylinder in a two-cycle internal combustion engine. [Structure] The engine speed N is read (S1), and the throttle valve opening α is read (S2). It is a map in which the cylinders to be ignited are discriminated (S3), and the ignition timing ADV is stored in advance for each of a plurality of divided operating states using the engine speed N and the throttle valve opening α as parameters. From the map corresponding to the determined cylinder among the maps provided for each cylinder so as to set the ignition timing ADV required for the above, the correspondence is made based on the current engine speed N and throttle valve opening α. The ignition timing ADV in the operating state is searched for and obtained (S4, S5), and ignition processing is performed (S6).

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to an ignition timing control device for a two-cycle internal combustion engine, and more particularly to a technique for performing optimum ignition timing control according to the ignition timing required for each cylinder.

[0002]

[Prior Art]

 As an ignition system for an internal combustion engine, for example, an electronically controlled system, in general, a basic ignition according to the operating state is subdivided into regions in which the engine operating region is subdivided based on the engine speed, engine load (fuel injection amount), etc. The timing is stored in the memory of the microcomputer, and the ignition timing is controlled based on the basic ignition timing retrieved from the memory according to the engine operating conditions (see Japanese Patent Laid-Open No. 60-184967, etc.). .

By the way, in a two-cycle internal combustion engine, the shape of the expansion chamber provided for each cylinder greatly affects the performance. However, such expansion chamber has the same shape in all cylinders due to restrictions in mounting on an actual vehicle. It doesn't. As a result, the expansion chambers do not have the same shape in all of the cylinders, resulting in a difference in filling efficiency due to the difference in the shape of the expansion chambers.

As a result, the ignition timing required for each cylinder inevitably differs.

[0005]

[Problems to be solved by the device]

 However, in the past, since the same ignition timing was set for all cylinders, the combustion zone of the engine was narrowed, which could cause problems such as detonation and seizure. Therefore, in view of the above conventional problems, the present invention has an object to perform optimal ignition timing control in accordance with the ignition timing required for each cylinder.

[0006]

[Means for Solving the Problems]

 For this reason, the ignition timing control device for a two-cycle internal combustion engine of the present invention, as shown in FIG. 1, has an ignition timing setting means for setting the ignition timing based on the engine operating state, which is required for each cylinder. Cylinder discriminating means for discriminating which cylinder should be ignited, and ignition timing set by the ignition timing setting means corresponding to the cylinder discriminated by the cylinder discriminating means. An ignition signal output means for outputting an ignition signal to the ignition device is provided.

[0007]

[Action]

 In such a configuration, the cylinder discriminating means discriminates the cylinder to be ignited, the ignition timing corresponding to this cylinder is set by the ignition timing setting means, and an ignition signal is output to the ignition device based on the set ignition timing. Even if the filling efficiency differs due to the difference in the shape of the expansion chamber provided for each cylinder, the ignition timing required for each cylinder can be controlled, so that the engine can be controlled. The combustion zone is expanded, and problems such as detonation and seizure can be prevented.

[0008]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In FIG. 2, for example, an intake hole 4, a scavenging hole 5, and an exhaust hole 6 are provided on the wall surface of a two-cycle two-cycle internal combustion engine 1, and the crank pressure is reduced by the low pressure generated in the lower part of the piston 7 during the compression stroke. When the air-fuel mixture is sucked into the chamber 2 through the intake hole 4 and the piston 7 passes through the exhaust hole 6 at the end of the work stroke, the combustion gas in the cylinder 3 is discharged through the exhaust hole 6 and further the piston 7 When the temperature decreases, the scavenging hole 5 communicates with the crank chamber 2, and the air-fuel mixture compressed in the crank chamber flows into the cylinder 3 to scavenge the exhaust gas.

An electromagnetic fuel injection valve 9 is provided in an intake passage 8 communicating with the intake hole 4, and a fuel-air mixture is formed by fuel injected and supplied from the fuel injection valve 9. To flow into the crank chamber 2. The fuel injection valve 9 is opened by a valve opening drive signal sent from a control unit 10 with a built-in microcomputer to inject and supply fuel adjusted to a predetermined pressure. The amount of fuel supply can be controlled depending on the time.

The control unit 10 receives a cylinder discrimination signal 11 output from a crank angle sensor attached to a crankshaft and an engine rotation signal based on the crank angle signal 12. Further, the control unit 10 includes a throttle valve 14 upstream of the fuel injection valve 9 which outputs an opening α signal of a throttle valve 14 and a water temperature sensor 13 which detects a cooling water temperature Tw of the engine 1. The atmospheric pressure signal from the atmospheric pressure sensor 16 and the intake air temperature signal from the intake air temperature sensor 17 are input, and the fuel injection amount is determined based on the detection signals output from these sensors. A valve opening drive signal corresponding to this is output to the fuel injection valve 9. A battery 17 voltage is applied to the control unit 10 via an ignition switch 15.

On the other hand, each cylinder of the engine 1 is provided with a spark plug 14. A high voltage generated by an ignition coil 18 is sequentially applied to the spark plugs 14, whereby spark ignition is performed to ignite and burn the air-fuel mixture. The ignition coil 18 has its high voltage generation timing controlled via a power transistor attached thereto. The ignition timing is controlled by controlling the ON / OFF timing of the power transistor through the CDi unit 19 by the ignition signal from the control unit 10 which also serves as the ignition signal output means.

An ignition device is configured by the spark plug 14, the ignition coil 18, and the power transistor. Next, ignition timing control by the control unit 10 will be described with reference to the flowchart of FIG. In this embodiment, the control unit 10 also serves as an ignition timing setting means and an ignition signal output means, as shown in the flow chart of the figure.

In step (abbreviated as S in the drawing; hereinafter the same) 1, the engine speed N is read, and in the next step 2, the throttle valve opening α is read. Then, in step 3, the cylinder for which the spark plug should be ignited is determined, and if the # 1 cylinder is determined, the process proceeds to step 4, and if the # 2 cylinder is determined, the process proceeds to step 5. In Steps 4 and 5, the ignition timing ADV (how many positions before the top dead center is indicated for each of a plurality of divided operating states using the engine speed N and the throttle valve opening α as parameters in advance, respectively). From the map corresponding to the determined cylinder among the maps provided for each cylinder so as to set the ignition timing ADV required for each cylinder, The ignition timing ADV in the corresponding operating state is searched and obtained based on the current engine speed N and the throttle valve opening α 1. When the ignition timing ADV is set in this way, the routine proceeds to step 6 and ignition processing is performed.

Specifically, the ON timing of the power transistor (the crank angle position calculated back from the ignition timing ADV and the required energization time) is measured using the cylinder discrimination signal from the crank angle sensor as a measurement reference, and the predetermined timing is measured. Then, the power transistor is turned on to start energizing the ignition coil 18, and the ignition timing ADV (power transistor OFF timing) is measured using the cylinder discrimination signal as a measurement reference. By turning off the power transistor, the power supply to the ignition coil 18 is cut off to generate a high voltage, and by applying this high voltage to the spark plug 14, spark ignition by the spark plug is performed.

According to the above configuration, the ignition timing ADV is stored in advance for each of a plurality of divided operating states with the engine speed N and the throttle valve opening α as parameters, and the ignition required for each cylinder is stored. Based on the current engine speed N and the throttle valve opening α, the ignition of the corresponding operating state is carried out from the map corresponding to the cylinder identified among the maps provided for the respective cylinders so as to set the timing ADV. Since the timing ADV is searched for and obtained, even if the charging efficiency differs due to the difference in the shape of the expansion chamber provided for each cylinder, the ignition timing required for each cylinder Therefore, the combustion zone of the engine can be expanded, and problems such as detonation and seizure can be prevented.

As described above, the present invention has been described with reference to the specific embodiments, but the present invention is not limited thereto, and is attached to the present invention by a person skilled in the art. It should be noted that various changes and modifications can be made without departing from the scope of the utility model registration claim.

[0017]

[Effect of the device]

 As described above, according to the ignition timing control device for a two-cycle internal combustion engine of the present invention, the ignition timing required for each cylinder can be controlled, the combustion zone of the engine can be expanded, and detonation and seizure can be performed. This is a great practical effect that can prevent the occurrence of such problems.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an ignition timing control device for a two-cycle internal combustion engine according to the present invention.

FIG. 2 is a system schematic diagram of an embodiment of the same device.

FIG. 3 is a flowchart showing ignition timing control in the embodiment.

[Explanation of symbols]

 1 2 cycle internal combustion engine 10 control unit 14 spark plug 18 ignition coil

Claims (1)

[Scope of utility model registration request] 1. A two-cycle internal combustion engine, comprising ignition timing setting means for setting ignition timing based on engine operating conditions,
Cylinder discriminating means for discriminating which cylinder should be ignited so as to set the ignition timing required for each cylinder, and the ignition timing corresponding to the cylinder discriminated by the cylinder discriminating means. An ignition timing control device for a two-cycle internal combustion engine, comprising: an ignition signal output device for outputting an ignition signal to an ignition device based on an ignition timing set by a setting device.