Patent Application
20210231093
The present invention relates to an internal combustion engine control device.
In recent years, in internal combustion engines, there is a demand for improving the performance of exhaust catalysts (three-way catalyst) as exhaust gas regulations are tightened. In exhaust catalysts of internal combustion engines, expensive precious metals such as platinum are used. However, as exhaust gas regulations are tightened, it is necessary to use many precious metals to improve exhaust performance, and the manufacturing cost of exhaust catalysts increases.
In this type of internal combustion engine, a large amount of hydrocarbons (HC) are generated especially at the time of cold start in which the temperature of the internal combustion engine is lower than the outside air temperature. Therefore, by suppressing the generation of hydrocarbons at the time of cold start, it is possible to reduce the amount of precious metal used in the exhaust catalyst and reduce the manufacturing cost of the exhaust catalyst.
However, in internal combustion engines, in order to prevent ignition failure (extinguishing) of the ignition device (ignition plug) at the time of cold start, control is performed to increase the fuel injection amount at the time of cold start. As a result, the amount of hydrocarbons generated at the time of cold start increases, and it becomes more difficult to reduce the cost of the exhaust catalyst.
In PTL 1, an engine ignition device is disclosed in which a temperature decrease of an ignition device is prevented when ignition of the ignition device is performed at a timing (exhaust timing) different from, a normal ignition timing in one combustion cycle of the internal combustion engine.
PTL 1: JP 62-20677 A
However, in the engine ignition device disclosed in PTL 1, the temperature decrease of the ignition plug is prevented after the temperature of the ignition plug of the internal combustion engine increases, and the temperature of the ignition plug increases before the cold start of the internal combustion engine. Therefore, it is not possible to suppress the generation of hydrocarbons in the internal combustion engine, especially at the time of cold start, and it becomes difficult to reduce the manufacturing cost of the exhaust catalyst.
Therefore, the present invention has been made in view of the above problems, and an object thereof is to suppress the generation of hydrocarbons in the internal combustion engine and reduce the manufacturing cost of the exhaust catalyst.
An internal combustion engine control device according to an aspect of the present invention includes: an ignition control unit which executes an ignition control for controlling an ignition plug which discharges electricity in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit executes the ignition control such that a predetermined ignition electric energy is supplied to the ignition plug when the ignition plug performs the ignition, and a predetermined pre-heating electric energy smaller than the ignition electric energy is supplied to the ignition plug before the ignition plug performs the ignition.
An internal combustion engine control device according to another aspect of the present invention includes: an ignition control unit which controls energization of an ignition coil which provides electric energy to an ignition plug which discharges electricity in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit controls the energization of the ignition coil such that the ignition plug is provided with the electric energy for heating the ignition plug before the ignition plug performs the ignition.
An internal combustion engine control device according to another aspect of the present invention includes: an ignition control unit which executes an ignition control for controlling an ignition plug which discharges electricity in a cylinder of an internal combustion engine to ignite fuel. The ignition control unit executes the ignition control such that an electric energy for causing the ignition plug to discharge electricity is supplied to the ignition plug in a period including at least an exhaust stroke in which the fuel after combustion is discharged from the cylinder.
According to the present invention, it is possible to suppress the generation of hydrocarbons in the internal combustion engine and reduce the manufacturing cost of the exhaust catalyst.
Hereinafter, an internal combustion engine control device according to a first embodiment of the present invention will be described.
Hereinafter, a control device 1 which is one mode of the internal combustion engine control device according to the first embodiment will be described. In this embodiment, a case where the control device 1 controls the discharge (ignition) of an ignition plug 200 provided in each cylinder 150 of a four-cylinder internal combustion engine 100 will be described as an example.
Hereinafter, in the embodiment, a combination of a partial or overall configuration of the internal combustion engine 100 and a partial or overall configuration of the control device 1 is referred to as the control device 1 of the internal combustion engine 100.
In the internal combustion engine 100, the air sucked from the outside flows through an air cleaner 110, an intake pipe 111, and an intake manifold 112, and flows into each cylinder 150 when an intake valve 151 opens. The amount of air flowing into each cylinder 150 is adjusted by a throttle valve 113, and the amount of air adjusted by the throttle valve 113 is measured by a flow rate sensor 114.
The throttle valve 113 is provided with a throttle opening sensor 113a which detects the opening of a throttle. The opening information of the throttle valve 113 detected by the throttle opening sensor 113a is output to the control device (Electronic Control Unit: ECU) 1.
Incidentally, as the throttle valve 113, an electronic throttle valve driven by an electric motor is used, but the throttle valve may be any other type as long as the flow rate of air can be appropriately adjusted.
The temperature of the gas flowing into each cylinder 150 is detected by an intake air temperature sensor 115.
A crank angle sensor 121 is provided outside a ring gear 120 attached to a crankshaft 123 in a radial direction. The crank angle sensor 121 detects the rotation angle of the crankshaft 123. In the embodiment, the crank angle sensor 121 detects the rotation angle of the crankshaft 123, for example, every 10° and each combustion cycle.
A water temperature sensor 122 is provided on a water jacket (not illustrated) of a cylinder head. The water temperature sensor 122 detects the temperature of the cooling water of the internal combustion engine 100.
A vehicle is provided with an accelerator position sensor (APS) 126 which detects a displacement amount (depression amount) of an accelerator pedal 125. The accelerator position sensor 126 detects the torque required by a driver. The torque required by the driver and detected by the accelerator position sensor 126 is output to the control device 1 described later. The control device 1 controls the throttle valve 113 on the basis of this required torque.
The fuel stored in a fuel tank 130 is sucked and pressurized by a fuel pump 131, then flows through a fuel pipe 133 provided with a pressure regulator 132, and is guided to a fuel injection valve (injector) 134. The fuel output from the fuel pump 131 is adjusted to have a predetermined pressure by the pressure regulator 132, and is injected from the fuel injection valve (injector) 134 into each cylinder 150. As a result of the pressure adjustment by the pressure regulator 132, excess fuel is returned to the fuel tank 130 via a return pipe (not illustrated).
The cylinder head (not illustrated) of the internal combustion engine 100 is provided with a combustion pressure sensor (CPS, also referred to as a cylinder pressure sensor) 140. The combustion pressure sensor 140 is provided in each cylinder 150 and detects the inner pressure (combustion pressure) of the cylinder 150.
As the combustion pressure sensor 140, a piezoelectric or gauge type pressure sensor is used, and the inner combustion pressure (in-cylinder pressure) of the cylinder 150 can be detected over a wide temperature range.
An exhaust valve 152 and an exhaust manifold 160 for discharging the gas (exhaust gas) after combustion to the outside of the cylinder 150 are attached to each cylinder 150. A three-way catalyst 161 is provided on the exhaust side of the exhaust manifold 160.
When the exhaust valve 152 is opened, exhaust gas is discharged from the cylinder 150 to the exhaust manifold 160. The exhaust gas purified by the three-way catalyst 161 while flowing through the exhaust manifold 160 and then is discharged to the atmosphere.
An upstream air-fuel ratio sensor 162 is provided on the upstream side of the three-way catalyst 161. The upstream air-fuel ratio sensor 162 continuously detects the air-fuel ratio of the exhaust gas discharged from each cylinder 150.
A downstream air-fuel ratio sensor 163 is provided on the downstream side of the three-way catalyst 161. The downstream air-fuel ratio sensor 163 outputs a switching detection signal in the vicinity of the theoretical air-fuel ratio. In the embodiment, the downstream air-fuel ratio sensor 163 is, for example, an 02 sensor.
Further, an ignition plug 200 is provided above each cylinder 150. Due to the discharge (ignition) of the ignition plug 200, a spark is ignited in the air-fuel mixture of air and fuel in the cylinder 150, an explosion occurs in the cylinder 150, and a piston 170 is pushed down. When the piston 170 is pushed down, a crankshaft 123 rotates.
An ignition coil 300 which generates electric energy (voltage) supplied to the ignition plug 200 is connected to the ignition plug 200. The voltage generated in the ignition coil 300 causes discharge between a center electrode 210 and an outer electrode 220 of the ignition plug 200 (see
As illustrated in
The outer electrode 220 is grounded. When a predetermined voltage is applied to the center electrode 210, a discharge (ignition) occurs between the center electrode 210 and the outer electrode 220.
Incidentally, in the ignition plug 200, the dielectric breakdown of the gas component occurs due to the state of the gas existing between the center electrode 210 and the outer electrode 220 or the in-cylinder pressure, and the voltage at which the discharge (ignition) occurs changes. This voltage at which the discharge occurs is referred to as a dielectric breakdown voltage.
The discharge control (ignition control) on the ignition plug 200 is performed by an ignition control unit 83 of the control device 1 described later.
Returning to
Next, the overall hardware configuration of the control device 1 will be described.
As illustrated in
Analog output signals from various sensors such as the throttle opening sensor 113a, the flow rate sensor 114, the accelerator position sensor 126, the upstream air-fuel ratio sensor 162, the downstream air-fuel ratio sensor 163, the combustion pressure sensor 140, and the water temperature sensor 122 are input to the analog input unit 10.
The A/D conversion unit 30 is connected to the analog input unit 10. The analog output signals input from various sensors to the analog input unit 10 are subjected to signal processing such as noise removal, converted into digital signals by the A/D conversion unit 30, and stored in the RAM 40.
The digital output signal from the crank angle sensor 121 is input to the digital input unit 20.
The I/O port 70 is connected to the digital input unit 20, and the digital output signal input to the digital input unit 20 is stored in the RAM 40 via the I/O port 70.
Each output signal stored in the RAM 40 is arithmetically processed by the MPU 50.
The MPU 50 executes a control program (not illustrated) stored in the ROM 60 to arithmetically process the output signal stored in the RAM 40 according to the control program. The MPU 50 calculates a control value that defines the operation amount of each actuator (for example, the throttle valve 113, the pressure regulator 132, and the ignition plug 200) which drives the internal combustion engine 100 according to the control program and temporarily stores the control value in the RAM 40.
The control value which is stored in the RAM 40 and defines the operation amount of the actuator is output to the output circuit 80 via the I/O port 70.
The output circuit 80 is provided with the function of the ignition control unit 83 (see
Next, the functional configuration of the control device 1 will be described.
As illustrated in
The overall control unit 81 is connected to an accelerator position sensor 126 and a combustion pressure sensor (CPS) 140 and receives the required torque (acceleration signal S1) from the accelerator position sensor 126 and an output signal S2 from the combustion pressure sensor 140.
The overall control unit 81 performs overall control on the fuel injection control unit 82 and the ignition control unit 83 on the basis of the required torque (acceleration signal S1) from the accelerator position sensor 126 and the output signal S2 from the combustion pressure sensor 140.
The fuel injection control unit 82 is connected to a cylinder determination unit 84 which determines each cylinder 150 of the internal combustion engine 100, an angle information generation unit 85 which measures the crank angle of the crankshaft 123, and a rotation speed information generation unit 86 which measures an engine speed and receives cylinder discrimination information S3 from the cylinder determination unit 84, crank angle information S4 from the angle information generation unit 85, and engine speed information S5 from the rotation speed information generation unit 86.
The fuel injection control unit 82 is connected to an intake amount measurement unit 87 which measures the intake amount of air taken into the cylinder 150, a load information generation unit 88 which measures an engine load, and a water temperature measurement unit 89 which measures the temperature of engine cooling water and receives intake amount information S6 from the intake amount measurement unit 87, engine load information S7 from the load information generation unit 88, and cooling water temperature information S8 from the water temperature measurement unit 89.
The fuel injection control unit 82 calculates the injection amount and the injection time (fuel injection valve control information S9) of fuel injected from the fuel injection valve 134 on the basis of the received information and controls the fuel injection valve 134 on the basis of the calculated injection amount and injection time of fuel.
The ignition control unit 83 is connected to the cylinder determination unit 84, the angle information generation unit 85, the rotation speed information generation unit 86, the load information generation unit 88, and the water temperature measurement unit 89 in addition to the overall control unit 81 and receives each information from these units.
The ignition control unit 83 calculate the amount (energization angle) of current for energizing a primary coil (not illustrated) of the ignition coil 300, an energization start time, and the time to cut off the current (ignition time) energizing the primary coil on the basis of the received information.
The ignition control unit 83 controls the discharge with the ignition plug 200 (ignition control) by outputting an ignition signal SA to a primary coil 310 of the ignition coil 300 on the basis of the calculated energization angle, energization start time, and ignition time.
Incidentally, at least the function of the ignition control unit 83 to control the ignition of the ignition plug 200 using the ignition signal SA corresponds to the internal combustion engine control device of the present invention.
Next, an electric circuit 400 including the ignition coil 300 will be described.
One end of the primary coil 310 is connected to a DC power supply 330. Accordingly, a predetermined voltage (for example, 12 V in the embodiment) is applied to the primary coil 310. A charge amount detection unit 350 is provided in the connection path between the DC power supply 330 and the primary coil 310. The charge amount detection unit 350 detects the voltage and current applied to the primary coil 310 and transmits the detected voltage and current to the ignition control unit 83.
The other end of the primary coil 310 is connected to an igniter 340 and is grounded via the igniter 340. A transistor, a field effect transistor (FET), or the like is used for the igniter 340.
The base (B) terminal of the igniter 340 is connected to the ignition control unit 83. An ignition signal SA output from the ignition control unit 83 is input to the base (B) terminal of the igniter 340. When the ignition signal SA is input to the base (B) terminal of the igniter 340, the collector (C) terminal and the emitter (E) terminal of the igniter 340 are energized, and current flows between the collector (C) terminal and the emitter (E) terminal. Accordingly, the ignition signal SA is output from the ignition control unit 83 to the primary coil 310 of the ignition coil 300 via the igniter 340, and electric power (electrical energy) is accumulated in the primary coil 310.
When the output of the ignition signal SA from the ignition control unit 83 is stopped, and the current flowing through the primary coil 310 is cut off, a high voltage corresponding to the turn number ratio of the coil with respect to the primary coil 310 is generated on the secondary coil 320. When the high voltage generated in the secondary coil 320 is applied to the ignition plug 200 (center electrode 210), a potential difference is generated between the center electrode 210 of the ignition plug 200 and the outer electrode 220. When the potential difference generated between the center electrode 210 and the outer electrode 220 is equal to or higher than the dielectric breakdown voltage Vm of the gas (the air-fuel mixture in the cylinder 150), the dielectric breakdown of the gas component causes the discharge to occur between the central electrode 210 and the outer electrode 220, and the fuel (air-fuel mixture) is ignited.
A discharge amount detection unit 360 is provided in the connection path between the secondary coil 320 and the ignition plug 200. The discharge amount detection unit 360 detects a discharge voltage and a current and transmits the detected discharge voltage and current to the ignition control unit 83.
By the operation of the electric circuit 400 as described above, the ignition control unit 83 controls the energization of the ignition coil 300 by using the ignition signal SA. Accordingly, the ignition control for controlling the ignition plug 200 is performed.
[Relationship between Ignition Plug Temperature and Air-Fuel Ratio]
Next, the relationship between the temperature of the ignition plug 200 and the air-fuel ratio will be described. At the time of the cold start of the internal combustion engine 100, as the temperature of the electrode of the ignition plug 200 decreases, it is necessary to reduce the air-fuel ratio required for ignition (thicken the fuel).
In a case where the dielectric breakdown voltage is constant (the output current of the ignition coil 300 is constant), when the temperature of the electrode of the ignition plug 200 decreases, the breakdown voltage is hardly exceeded unless the air-fuel ratio is reduced (fuel is thickened). As a result, in the internal combustion engine 100, the amount of hydrocarbons (HG) generated during combustion increases as the proportion of fuel in the air-fuel mixture increases.
In other words, when the temperature of the electrode of the ignition plug 200 at the time of cold start increases (see a thick arrow in
In the example illustrated in
Next, the output timing of the ignition signal SA will be described regarding the method of heating the electrodes of the ignition plug 200 according to the first embodiment.
In
The third stage from the top shows the output signal of the crank angle sensor 121. After the ignition switch is turned on, a cell motor switch is turned on, and when the crank angle sensor 121 starts detecting the rotation of the crankshaft 123 with the start of movement of the internal combustion engine 100, the output of the crank angle sensor 121 is turned on.
The fourth stage from the top shows the ignition signal SA output from the ignition control unit 83 to the ignition coil 300. The ignition signal SA includes a preliminary ignition signal Sp and a main ignition signal Sa output after the preliminary ignition signal Sp. The preliminary ignition signal Sp is an ignition signal for supplying the pre-heating electrical energy to the ignition plug 200 to increase the temperature of the ignition plug 200 before the ignition plug 200 ignites the fuel (air-fuel mixture) at the time of cold start of the internal combustion engine 100. At the time of cold start, the preliminary ignition signal Sp is output from the ignition control unit 83 to the ignition coil 300, so that the temperature of the electrode of the ignition plug 200 can be increased before discharge (ignition) as described in
On the other hand, the main ignition signal Sa is an ignition signal for the ignition plug 200 to ignite (ignite) the air-fuel mixture in the combustion stroke of the internal combustion engine 100. The output timing of the main ignition signal Sa is determined by the ignition control unit 83 as described in
In the first embodiment, the ignition control unit 83 outputs the main ignition signal Sa for causing the ignition plug 200 to discharge electricity (ignition) to the ignition coil 300 from time T4 to time T5 in the combustion stroke in the combustion cycle. Further, in the stroke before the combustion stroke in one combustion cycle, that is, in the stroke before the ignition plug 200 ignites the fuel, the preliminary ignition signal Sp for heating the ignition plug 200 is output to the ignition coil 300. Hereinafter, the heating of the ignition plug 200 by the preliminary ignition signal Sp is also referred to as pre-heating.
As illustrated in
As illustrated in
As illustrated in
As described above, in the first embodiment, the ignition control unit 83 outputs the preliminary ignition signal Sp a plurality of times before outputting the main ignition signal Sa. Accordingly, before the ignition plug 200 ignites the air-fuel mixture (fuel), the ignition control unit 83 controls the energization of the coil 300 so that the ignition coil 300 provides the ignition plug 200 with electric energy for heating the ignition plug 200. At this time, the ignition control unit 83 outputs the pulse signal of the preliminary ignition signal Sp with a pulse width smaller than the pulse signal of the main ignition signal Sa. Accordingly, before the ignition plug 200 ignites the air-fuel mixture (fuel), the ignition control of the ignition plug 200 is executed such that a predetermined pre-heating electric energy smaller than the ignition electric energy is supplied to the ignition plug 200. When a high voltage is applied from the ignition coil 300 to the ignition plug 200 on the basis of the preliminary ignition signal Sp, at the time of cold start of the internal combustion engine 100, the ignition plug 200 (the center electrode 210 and the outer electrode 220) is heated before the first explosion. As a result, as described above, although the air-fuel ratio at the time of discharge (ignition) of the ignition coil 300 in the combustion stroke is increased (the fuel is thinned), the generation of hydrocarbons (HC) due to combustion at the time of cold start can be suppressed.
Next, the fifth stage from the top shows ON/OFF of the fuel injection valve 134. When the fuel injection valve 134 is turned on, a predetermined amount of fuel is injected through the fuel injection valve 134 into the cylinder 150 (combustion chamber).
The bottom row shows the in-cylinder pressure in the cylinder 150 (combustion chamber). The in-cylinder pressure is measured by the combustion pressure sensor 140, and the measurement result of the combustion pressure sensor 140 is output. As described above, in the internal combustion engine 100, after the predetermined amount of fuel is injected through the fuel injection valve 134 to generate the air-fuel mixture in the combustion chamber, the air-fuel mixture is ignited at the timing (time T5) when the main ignition signal Sa is turned off, and combustion occurs. Accordingly, the pressure in the cylinder 150 rapidly increases. The combustion pressure sensor 140 measures the in-cylinder pressure in the combustion cycle.
Next, an example of a control method of the ignition plug 200 by the ignition control unit 83 will be described.
As illustrated in
In step S102, the ignition control unit 83 determines whether or not the cylinder 150 is after the first explosion. In a case where the main ignition signal Sa is turned on even once, it is determined that the cylinder is after the first explosion (step S102: YES), and the process ends as it is. On the other hand, when the main ignition signal Sa is not turned on even once after the ignition switch is turned on, it is determined that the cylinder is before the first explosion (step S102: NO), and the process proceeds to step S103.
In step S103, the ignition control unit 83 determines whether or not fuel is injected into the cylinder 150. In a case where the fuel injection valve 134 is turned on even once, it is determined that the fuel is injected (step S103: YES), and the process proceeds to step S105. On the other hand, when the fuel injection valve 134 is not turned on even once after the ignition switch is turned on, it is determined that the fuel injection is not performed (step S103: NO), and the process proceeds to step S104.
In step S104, the ignition control unit 83 sets the output cycle of the preliminary ignition signal Sp to be long. After step S104 is executed, the ignition control unit 83 proceeds to step S106, and in step S106, outputs the preliminary ignition signal Sp at the output cycle set in step S104. Accordingly, the discharge control (ignition control) on the ignition plug 200 is executed such that the voltage generated in the ignition coil 300 becomes equal to or higher than the dielectric breakdown voltage, and the ignition plug 200 discharges electricity by the pre-heating electric energy supplied from the ignition coil 300 to the ignition plug 200 to generate a spark.
In step S105, the ignition control unit 83 sets the output cycle of the preliminary ignition signal Sp to be short. After step S105 is executed, the ignition control unit 83 proceeds to step S106, and in step S106, outputs the preliminary ignition signal Sp at the output cycle set in step S105. Accordingly, the discharge control (ignition control) on the ignition plug 200 is executed such that the voltage generated in the ignition coil 300 becomes lower than the dielectric breakdown voltage, and a spark is not generated without the ignition plug 200 discharging electricity by the pre-heating electric energy supplied from the ignition coil 300 to the ignition plug 200.
After the preliminary ignition signal Sp is output in step S106, the process returns to step S101. Accordingly, the discharge control (ignition control) on the ignition plug 200 is executed such that the output cycle of the preliminary ignition signal Sp is changed before and after the fuel injection, and the output of the preliminary ignition signal Sp is ended after the first explosion.
As described above, in the first embodiment, the ignition plug 200 provided in the cylinder 150 and the ignition control unit 83 which controls the discharge of the ignition plug 200 are included. In the first combustion cycle after the start of the operation of the internal combustion engine 100, the ignition control unit 83 is configured to supply the pre-heating electric energy from the ignition coil 300 to the ignition plug 200 until the output of the main ignition signal Sa is started after the ignition switch is turned on. With this configuration, the ignition plug 200 can be pre-heated before the first explosion of each cylinder 150 in the internal combustion engine 100, and thus the generation of hydrocarbons (Ho) at the time of cold start can be suppressed.
In the first embodiment, the ignition control unit 83 is configured to supply the pre-heating electric energy from the ignition coil 300 to the ignition plug 200 a plurality of times in the first combustion cycle after the start of the operation of the internal combustion engine 100. With this configuration, the pre-heating of the ignition plug 200 can be reliably performed, so that the generation of hydrocarbons (HO) at the time of cold start can be reliably suppressed.
According to the first embodiment of the present invention described above, the following operational effects are exhibited.
(1) The internal combustion engine control device includes the ignition control unit 83 which executes an ignition control for controlling the ignition plug 200 which discharges electricity in the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 executes the ignition control such that a predetermined ignition electric energy is supplied to the ignition plug 200 when the ignition plug 200 performs ignition, and a predetermined pre-heating electric energy smaller than the ignition electric energy is supplied to the ignition plug 200 before the ignition plug 200 performs ignition. Therefore, it is possible to suppress the generation of hydrocarbons at the time of cold start of the internal combustion engine 100 and to reduce the manufacturing cost of the exhaust catalyst.
(2) The ignition control unit 83 executes the ignition control such that the pre-heating electric energy is supplied to the ignition plug 200 before the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel (between time T1 and time T3). Therefore, the pre-heating of the ignition plug 200 can be performed at a timing appropriate for suppressing the generation of hydrocarbons at the time of cold start of the internal combustion engine 100.
(3) The ignition control unit 83 executes the ignition control such that the pre-heating electric energy is supplied to the ignition plug 200 between a time when the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel and a time when the ignition electric energy is supplied to the ignition plug 200 (between time T3 and time T4). Therefore, the pre-heating of the ignition plug 200 can be performed at a timing appropriate for suppressing the generation of hydrocarbons at the time of cold start of the internal combustion engine 100.
(4) The ignition control unit 83 executes the ignition control such that a first electric energy is supplied as the pre-heating electric energy to the ignition plug 200 before the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel (between time T1 and time T3). Further, the ignition control unit 83 executes the ignition control such that a second pre-heating electric energy is supplied as the pre-heating electric energy to the ignition plug 200 between a time when the fuel injection valve 134 injects the fuel and a time when the ignition electric energy is supplied to the ignition plug 200 (between time T3 and time T4). Here, the first electric energy is larger than the second electric energy. Therefore, it is possible to supply appropriate pre-heating electric energy to the ignition plug 200 before and after fuel injection.
(5) The ignition control unit 83 executes the ignition control such that the ignition plug 200 discharges electricity by the pre-heating electric energy to generate a spark before the fuel injection valve 134 injects the fuel (between time T1 and time T3). Therefore, in the period before the fuel injection without the possibility of erroneous ignition, the pre-heating of the ignition plug 200 can be performed efficiently.
(6) The ignition control unit 83 executes the ignition control such that a spark is not generated without the ignition plug 200 discharging electricity by the pre-heating electric energy between a time when the fuel injection valve 134 injects the fuel and a time when the ignition electric energy is supplied to the ignition plug 200 (between time T3 and time T4). Therefore, it is possible to perform the pre-heating of the ignition plug 200 while preventing erroneous ignition during the compression stroke.
(7) The ignition control unit 83 executes the ignition control such that the pre-heating electric energy is supplied to the ignition plug 200 a plurality of times per ignition. Therefore, the pre-heating of the ignition plug 200 can be performed reliably.
(8) The ignition control unit 83 executes the ignition control such that the pre-heating electric energy is supplied to the ignition plug 200 a plurality of times before the fuel injection valve 134 injects the fuel. Therefore, the pre-heating of the ignition plug 200 can be performed reliably.
(9) The ignition control unit 83 executes the ignition control such that the pre-heating electric energy is supplied to the ignition plug 200 a plurality of times between a time when the fuel injection valve 134 injects the fuel and a time when the ignition electric energy is supplied to the ignition plug 200. Therefore, the pre-heating of the ignition plug 200 can be performed reliably.
(10) The internal combustion engine control device 1 includes the ignition control unit 83 which controls energization of the ignition coil 300 which provides electric energy to the ignition plug 200 which discharges electricity in the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 controls the energization of the ignition coil 300 such that the ignition plug 200 is provided with the electric energy for heating the ignition plug 200 before the ignition plug 200 performs the ignition. Therefore, it is possible to suppress the generation of hydrocarbons at the time of cold start of the internal combustion engine 100 and to reduce the manufacturing cost of the exhaust catalyst.
(11) The ignition control unit 83 controls the energization of the ignition coil 300 by continuously transmitting the preliminary ignition signal Sp which is a pulse signal at a first frequency to the igniter 340 connected to the ignition coil 300 before the fuel injection valve 134 attached to the internal combustion engine 100 injects the fuel (between time T1 and time T3). Further, the ignition control unit 83 controls the energization of the ignition coil 300 by continuously transmitting the preliminary ignition signal Sp which is a pulse signal at a second frequency to the igniter 340 between a time when the fuel injection valve 134 injects the fuel and a time when the ignition plug 200 performs the ignition (between time T3 and time T4). Here, the first frequency is lower than the second frequency. Therefore, it is possible to reliably supply appropriate pre-heating electric energy to the ignition plug 200 before and after fuel injection.
(12) The ignition control unit 83 controls the energization of the ignition coil 300 such that the ignition plug 200 is provided with the electric energy for heating the ignition plug 200 before the ignition plug 200 performs the ignition at a time of start of the internal combustion engine 100. Therefore, the electric energy required for the pre-heating of the ignition plug 200 can be reliably supplied from the ignition coil 300 to the ignition plug 200.
Next, an internal combustion engine control device according to a second embodiment of the present invention will be described.
In the second embodiment, an example will be described in which the control device 1 performs ignition control so that discharge (ignition) is generated in the ignition plug 200 during the exhaust stroke in the combustion cycle. Incidentally, the configurations of the internal combustion engine 100 and the control device 1 according to the second embodiment are the same as those of the first embodiment, and thus the description thereof is omitted below.
The output timing of the ignition signal SA according to the second embodiment will be described below.
In
On the other hand, the exhaust ignition signal Se is an ignition signal to supply the ignition plug 200 with the electric energy for causing the ignition plug 200 to discharge electricity in the period including at least the exhaust stroke of the internal combustion engine 100. When the exhaust ignition signal Se is output from the ignition control unit 83 to the ignition coil 300, the ignition plug 200 can be caused to discharge electricity even during the exhaust stroke in which the combusted fuel is discharged from the cylinder 150. Accordingly, it is conceivable that the fuel in the air-fuel mixture which cannot be combusted in the combustion stroke, such as fuel adhering to the wall surface of the cylinder 150 or the crown surface of the piston 170, can be ignited and combusted during exhaust. As a result, the generation of hydrocarbons (HC) can be suppressed.
In the second embodiment, the ignition control unit 83 outputs the main ignition signal Sa for causing the ignition plug 200 to discharge electricity (ignition) to the ignition coil 300 from time T4 to time T5 in the combustion stroke in the combustion cycle. Further, the exhaust ignition signal Se for causing the ignition plug 200 to discharge electricity (ignition) is output to the ignition coil 300 in the period after the combustion stroke in one combustion cycle, that is, in the period including at least the exhaust stroke.
As illustrated in
As illustrated in
Comparing
As described above, in the second embodiment, the ignition control unit 83 outputs the exhaust ignition signal Se a plurality of times in the period including at least the exhaust stroke after outputting the main ignition signal Sa. Accordingly, during the exhaust stroke, the ignition control unit 83 controls the energization of the ignition coil 300 so that the ignition coil 300 provides the ignition plug 200 with the electric energy for causing the ignition plug 200 to discharge electricity. When a high voltage is applied from the ignition coil 300 to the ignition plug 200 on the basis of the exhaust ignition signal Se, the ignition plug 200 is discharged during the exhaust stroke of the internal combustion engine 100, and the fuel in the air-fuel mixture which cannot be combusted in the combustion stroke can be ignited and combusted.
As a result, although the air-fuel ratio at the time of discharge (ignition) of the ignition coil 300 in the combustion stroke is increased (the fuel is thinned), the generation of hydrocarbons (HC) can be suppressed.
Next, in
The bottom row shows the in-cylinder pressure in the cylinder 150 (combustion chamber). The in-cylinder pressure is measured by the combustion pressure sensor 140, and the measurement result of the combustion pressure sensor 140 is output. As described above, in the internal combustion engine 100, after the predetermined amount of fuel is injected through the fuel injection valve 134 to generate the air-fuel mixture in the combustion chamber, the air-fuel mixture is ignited at the timing (time T5) when the main ignition signal Sa is turned off, and combustion occurs. Accordingly, the pressure in the cylinder 150 rapidly increases. The combustion pressure sensor 140 measures the in-cylinder pressure in the combustion cycle.
Next, an example of a control method of the ignition plug 200 by the ignition control unit 83 will be described.
As illustrated in
In step S202, the ignition control unit 83 determines whether or not the main ignition signal Sa changes from ON to OFF. In a case where the main ignition signal Sa changes from ON to OFF, that is, a case where the ignition plug 200 discharges to ignite the air-fuel mixture (step S202: YES), the process proceeds to step S203, and in a case where it is determined that the signal does not change from ON to OFF (step S202: NO), the process returns to step S202.
In step 3203, the ignition control unit 83 determines whether or not the operating state of the internal combustion engine 100 is a state after warming up. In a case where the state is a state after warming up, that is, in a case where a certain amount of time elapses since the internal combustion engine 100 starts to operate, and the internal combustion engine is a steady operating state (step S203: YES), the process proceeds to step S205. On the other hand, in a case where the state is not a state after warming up, that is, at the time of cold start of the internal combustion engine 100 (step S203: NO), the process proceeds to step S204.
In step 3204, the ignition control unit 83 sets the output cycle of the exhaust ignition signal Se to be long. After step S204 is executed, the ignition control unit 83 proceeds to step 3206, and in step S206, outputs the exhaust ignition signal Se at the output cycle set in step S204. Accordingly, the discharge control (ignition control) on t ignition plug 200 is executed such that the ignition plug 200 discharge electricity by the electric energy supplied from the ignition coil 300 to the ignition plug 200 during the exhaust stroke to generate a spark.
In step S205, the ignition control unit 83 sets the output cycle of the exhaust ignition signal Se to be short. After step S205 is executed, the ignition control unit 83 proceeds to step S206, and in step S206, outputs the exhaust ignition signal Se at the output cycle set in step S205. Accordingly, the discharge control (ignition control) on the ignition plug 200 is executed such that the ignition plug 200 discharge electricity by the electric energy supplied from the ignition coil 300 to the ignition plug 200 during the exhaust stroke to generate a spark.
After the exhaust ignition signal Se is output in step S206, the process returns to step S202. Accordingly, every time the ignition plug 200 discharges, and the combustion stroke is performed, the discharge control (ignition control) on the ignition plug 200 is executed such that the exhaust ignition signal Se is output in the period including at least the subsequent exhaust stroke, and the output cycle of the exhaust ignition signal Se is changed at the time of cold start and after warming-up. Incidentally, when a predetermined time elapses since the internal combustion engine 100 starts to operate, the processing illustrated in the flowchart of
As described above, in the second embodiment, the ignition plug 200 provided in the cylinder 150 and the ignition control unit 83 which controls the discharge of the ignition plug 200 are included. The ignition control unit 83 is configured to supply electric energy from the ignition coil 300 to the ignition plug 200 in the period including at least the exhaust stroke of the internal combustion engine 100. With this configuration, the fuel left in the air-fuel mixture discharged from each cylinder 150 in the internal combustion engine 100 can be combusted, and thus the generation of hydrocarbons (HC) at the time of cold start can be suppressed.
In the second embodiment, the ignition control unit 83 is configured to supply the discharging electric energy from the ignition coil 300 to the ignition plug 200 a plurality of times in the period including at least the exhaust stroke of the internal combustion engine 100. With this configuration, the ignition plug 200 can reliably discharge electricity during the exhaust stroke, so that the generation of hydrocarbons (HC) can be reliably suppressed.
According to the second embodiment of the present invention described above, the following operational effects are exhibited.
(1) The internal combustion engine control device 1 includes the ignition control unit 83 which executes an ignition control for controlling the ignition plug 200 which discharges electricity in the cylinder 150 of the internal combustion engine 100 to ignite fuel. The ignition control unit 83 executes the ignition control such that the electric energy for causing the ignition plug 200 to discharge electricity is supplied to the ignition plug 200 in a period including at least the exhaust stroke in which the fuel after combustion is discharged from the cylinder 150 (a period after time T6). Therefore, it is possible to suppress the generation of hydrocarbons at the time of cold start of the internal combustion engine 100 and to reduce the manufacturing cost of the exhaust catalyst.
(2) The exhaust stroke is a period during which the exhaust valve 152 of the internal combustion engine 100 is open. Therefore, by opening the exhaust valve 152, it is possible to reliably combust the fuel left in the air-fuel mixture discharged from each cylinder 150 and to suppress the generation of hydrocarbons.
(3) The ignition control unit 83 executes the ignition control such that the ignition plug 200 discharges electricity a plurality of times during the period. Therefore, the ignition plug 200 can be reliably caused to discharge electricity during the exhaust stroke, and the fuel left in the discharged air-fuel mixture can be combusted.
(4) A discharge cycle of the ignition plug 200 in the period is shorter than a discharge cycle when the ignition plug 200 ignites the fuel during the combustion stroke. Therefore, it is possible to reliably combust the fuel left in the air-fuel mixture discharged from the cylinder 150 at any timing during the exhaust stroke.
(5) The ignition control unit 83 executes the ignition control such that the discharge cycle of the ignition plug 200 in the period is within a range from a predetermined lower limit value to an upper limit value, and the lower limit value is changed according to a time elapsed after start of the internal combustion engine 100. Therefore, the generation of hydrocarbons can be reliably suppressed both at the time of cold start and after warming-up.
Incidentally, the first embodiment and the second embodiment described above may be combined. That is, at the time of cold start of the internal combustion engine 100, the ignition control unit 83 outputs the preliminary ignition signal Sp before the first explosion to pre-heat the ignition plug 200 and outputs the exhaust ignition signal Se to discharge the ignition plug 200 in the period including at least the exhaust stroke, thereby suppressing the generation of hydrocarbons (HC). Further, after the warming-up (during steady operation) of the internal combustion engine 100, the ignition control unit 83 outputs the exhaust ignition signal Se to discharge the ignition plug 200 in the period including at least the exhaust stroke, thereby suppressing the generation of hydrocarbons (HC). With this configuration, the internal combustion engine control device 1 can be configured to achieve the respective operational effects described in the first embodiment and the second embodiment.
In each of the embodiments described above, each functional configuration of the control device 1 described in
The embodiments and various modifications described above are merely examples, and the present invention is not limited to these contents unless the characteristics of the invention are impaired. Further, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other embodiments considered within the scope of the technical idea of the present invention are also included within the scope of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-099160 | May 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/004960 | 2/13/2019 | WO | 00 |
