KR20010020823A - Control apparatus for direct injection type internal combustion engine - Google Patents

Abstract

PURPOSE: A control device of an internal-cylinder injection type engine are provided to maximize the performance of an internal combustion engine by suppressing the knocking of the engine under particular conditions. CONSTITUTION: The control device injectors(11), an air flow sensor(2), a crank angle sensor(5), a throttle valve opening sensor(4), a cylinder discriminator, a knock sensor(15), and an operation controller(8). The injector(11) directly injects fuel to respective cylinders of an internal combustion engine(1). The operation controller(8) calculates the fuel injection amount of the internal combustion engine(1) in accordance with the detection signals of the air flow sensor, the crank angle sensor and the throttle valve opening sensor as well as transmits the fuel injection amount to the injector as an electric signal and controls the fuel injection of the engine.

Description

CONTROL APPARATUS FOR DIRECT INJECTION TYPE INTERNAL COMBUSTION ENGINE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fuel injection control of an internal combustion engine (engine) for automobiles in a cylinder injection type that directly injects fuel into a cylinder (in a cylinder).

FIG. 5 is a diagram schematically showing the configuration of an internal combustion engine and a control device provided with a cylinder injection system. FIG.

In Fig. 5, the internal combustion engine 1 of the in-vehicle injection type for automobiles operates with an air flow sensor 2 for measuring the intake air amount of the internal combustion engine. The throttle valve 3 for detecting the position of the throttle valve 3, the throttle opening degree sensor 4 for detecting the position of the throttle valve 3, the crank angle sensor 5 for detecting the speed of the internal combustion engine and the position of the crankshaft, and the warming state of the internal combustion engine. Water temperature sensor (6) for detecting cooling water temperature, O2 sensor (7) for detecting oxygen concentration of exhaust gas discharged from internal combustion engine, operation control device (8), ignition plug (9), air bypass Valve 10, an injector 11 for supplying fuel into the cylinder, a cylinder identification sensor 14 mounted on the camshaft for identifying the combustion cylinder, and a rust sensor 15 for detecting the knocking state of the internal combustion engine. Doing.

In addition, in the control of the fuel injection amount, the fuel injection amount may be controlled in accordance with the intake pressure, the throttle opening volumetric efficiency, or the filling efficiency.

The operation control device 8 judges the operation state of the internal combustion engine according to the detection signals from the airflow sensor 2, the throttle opening sensor, and the crank angle sensor 5, calculates various control quantities according to the operation state, and calculates the internal combustion engine. It is a control unit (ECU) for burning at a constant air-fuel ratio. The air bypass valve 10 controls the amount of air that bypasses the throttle valve 3, and controls the internal combustion engine speed during the idling operation when the throttle is fully closed. The indexer 11 is driven by an electrical command signal transmitted from the indexer driver 13. The EGR valve 12 is a valve for controlling the amount of EGR for returning (EGR) the combustion gas of the internal combustion engine back to the combustion chamber (EGR) for the purpose of reducing NO x. In addition, the spark plug 9, the air bypass valve 10, the EGR valve 12, and the injector 11 are all controlled by the operation control device 8, and the injector 11 is controlled by the injector 11. It is driven by the driver (13).

The internal combustion engine equipped with the control system of the internal injection type internal combustion engine having such a configuration is attracting attention as an ideal internal combustion engine in which the following four effects are expected.

(1) Reduction of emissions of exhaust gas

In the conventional method of injecting fuel from outside of the cylinder, a part of the injected fuel is attached to the intake valve intake pipe wall before being sucked into the cylinder, which requires a relatively quick supply fuel change response during a low temperature start-up movement that is difficult to vaporize. In transient operation, it is necessary to consider attached fuel. On the other hand, the internal combustion engine of in-cylinder injection type can reduce the air-fuel ratio without considering fuel transportation delay, thereby reducing the emission of HC.CO.

(2) fuel economy

When the fuel is injected into the barrel, the fuel is injected at the ignition timing immediately before ignition, and the combustion state, that is, the stratified combustion, becomes uneven in the mixture of the combustible fuel formed around the ignition plug at the ignition plug. As a result, it is possible to significantly reduce the apparent air-fuel ratio of the amount of air sucked into the barrel and the amount of fuel, and to realize stratified combustion, even if the ERG is introduced in a large amount, the impact on combustion deterioration is reduced and the pumping loss is also reduced. In addition, the fuel efficiency can be improved.

(3) Improvement of output of internal combustion engine

By realizing stratified combustion, by mixing the mixer around the spark plug, the end gas, which is the cause of knocking, can be reduced, thereby improving rust resistance and increasing the compression ratio of the internal combustion engine. In addition, since the fuel vaporizes in the cylinder, the heat of vaporization of the intake air is taken out of the cylinder, thereby increasing the intake air density and increasing the volumetric efficiency, thereby improving the output of the internal combustion engine.

(4) Improvement of driver ability

By directly injecting the fuel into the cylinder, it is possible to realize an internal combustion engine that has a shorter delay between the fuel supply and the output after the fuel is supplied compared to the conventional internal combustion engine and responds to the needs of the driver. As a conventional technique related to rust control with respect to a conventional in-cylinder injection type internal combustion engine having the above-described effects, there is an invention described in Japanese Patent Laid-Open No. 4-183951. In the invention described in the publication, the timing of ignition at the time of rust generation and the timing of injection of the compression stroke are advanced to suppress the knocking.

Knocking occurs when the end gas in the cylinder self-ignites and burns at a timing different from the original ignition timing by the spark plug. Therefore, when fuel is present only in the vicinity of the spark plug, such as compression stroke injection, it is hard to cause knocking, but the compression ratio of the internal combustion engine itself is set high, the ignition timing is set on the true side, and the intake temperature itself is high, and the volatile fuel is high. There is a possibility that knocking occurs due to self ignition in special situations where the fuel is used and the lamination of the fuel is not complete.

In the cylinder injection control system, as described above, the fuel is supplied at the time of compression type, the ultra thin layer is burned to improve the emission and fuel efficiency, and the fuel is supplied at the time of the intake stroke. There is a normal operation mode of operation.

In the compression stroke injection mode (lean mode), as shown in (2), the fuel consumption is greatly reduced, and as shown in (3), knocking is difficult in principle. . For this reason, in setting the compression ratio and ignition timing of an internal combustion engine, it can be set as the setting which gives priority to the improvement of an internal combustion engine output.

However, assuming a special situation, such as driving a vehicle with high volatility under a very high temperature and dry environment in which a vehicle can operate, the compression ratio and the ignition timing that sacrifice some fuel economy or internal combustion engine power cannot be avoided.

As a result, even the situation that most users do not use is set to the characteristics of the internal combustion engine, which is assumed, and at the expense of fuel economy of the vehicle in the overnight situation. Since the combustion in the compression stroke injection mode is established by the fuel injection timing and the subtle timing of the ignition timing, a large change in the timing of either or both of the fuel injection ignitions is likely to cause combustibility. If knocking occurs, it is due to the inability to perceive the ignition timing like conventional rust control.

Fig. 6 is a view showing the operation contents of the internal combustion engine by the operation control apparatus of the conventional in-cylinder injection type internal combustion engine. The characteristic shown in Fig. 6 is the combustion stroke state of each cylinder detected according to the output signal SGT, the output signal SGC and the SGT of the output signal SGC crank angle sensor 5 of the cylinder identification sensor 14 in order from the top. Timing Each time of knocking is displayed. In addition, from left to right in the figure, the output signal of each sensor and the shape of the time change of the combustion process are shown.

As shown in FIG. 6, in the conventional apparatus, when knocking occurs at time T9 in the combustion of the third cylinder # 3, the operation control device reads the output signal of the rust sensor at time T4 (output degree of crank angle sensor). However, since it is a compression stroke injection, the fuel injection amount and the ignition timing of the injector of the fourth cylinder (# 4) are controlled at time T14 without rust control. Therefore, at the time T10, the fourth cylinder (# 4) is continuously controlled. Since knocking occurred and the control amount of fuel injection amount and ignition timing did not change without knock control afterwards, knocking occurred continuously at times T11 and T12.

Accordingly, the present invention is to enable the suppression of knocking even if knocking has occurred during the compression stroke injection operation in the above-described cylinder injection internal combustion engine. Therefore, the present invention aims to fully exhibit the potential of the internal injection type internal combustion engine by setting the characteristics of the output priority internal combustion engine for the purpose of improving fuel economy in such a configuration.

The operation control apparatus of the in-cylinder injection type internal combustion engine of the present invention includes an injector installed to directly inject fuel into each cylinder of the internal combustion engine, an intake amount detecting means for detecting an intake amount of the internal combustion engine, a crank angle detection means for detecting a crank angle of the internal combustion engine, and a throttle According to the detection signal of the throttle valve detecting means for detecting the valve opening, the cylinder identifying means for identifying the cylinder to be burned, the rust detecting means for detecting the knocking of the internal combustion engine, the intake air amount detecting means, the crank angle detecting means or the throttle valve opening detecting means. When the fuel injection amount of the internal combustion engine is calculated, and the fuel injection amount is transmitted to the indexer as an electric signal and the fuel injection control of the internal combustion engine is provided, and the knocking occurs in the operation state where the fuel injection is performed in the compression stroke. When inknock occurs, fuel is injected into the cylinder in the intake type. The.

In addition, it is characterized in that the amount of fuel injected into the cylinder in the intake stroke is variably controlled according to the knocking state.

In addition, the amount of fuel injected into the cylinder by the intake stroke is set so as to have an air-fuel ratio which does not ignite in the cylinder.

The amount of fuel injected into the cylinder at the intake stroke is the amount of fuel injected from the compression stroke when the output torque obtained by burning the sum of the fuel amount and the amount of fuel injected into the cylinder at the compression stroke following the intake stroke is not knocked. It is characterized in that it is set to be approximately equal to the output torque.

1 is a view showing the operation of the internal combustion engine by the operation control device of the internal injection internal combustion engine of the present invention;

FIG. 2 is a flowchart showing the processing contents of the control apparatus at the time TDC (loading timing of SGT times) in FIG.

FIG. 3 is a flow chart showing the processing contents of the control device at time 70 ° B in FIG.

Fig. 4 is a flowchart showing the contents of the control amount calculation processing of the control device performed at a predetermined time;

FIG. 5 is a diagram schematically showing the configuration of an internal combustion engine and a control device having an in-cylinder injection system; FIG.

6 is a view showing the operation content of the internal combustion engine for the operation control device of the internal combustion internal combustion engine

<Description of the symbols for the main parts of the drawings>

1: internal combustion engine, 2: airflow sensor (air intake detection means),

4: throttle opening degree sensor (throttle valve opening degree detecting means),

5: crank angle sensor (crank angle detection means), 8: operation control device,

11: detector, 14: cylinder identification sensor (cylinder identification means),

15: Rust sensor (rust detection means).

Embodiment 1

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing the operation contents of an internal combustion engine by an operation control apparatus of an internal injection type internal combustion engine of the present invention. Moreover, the output signal of each sensor and the time change of a combustion process are shown from left to right in the figure. The configuration of the internal combustion engine according to the first embodiment is the same as that of the conventional apparatus shown in Fig. 5, and the operation control apparatus of the internal injection type internal combustion engine according to the present invention is characterized by the processing contents of the operation control apparatus 8. The air flow sensor 2 is an intake air amount detecting means, the throttle opening degree sensor 4 is a throttle valve opening degree detecting means, the crank angle sensor 5 is a crank angle detecting means, and the cylinder identification sensor 14 is a rust sensor. 15 each function as a rust detection means. In the control of the fuel injection amount, not only the intake amount but also the intake pressure throttle dog may control the fuel injection amount according to the volumetric efficiency or the filling efficiency.

Specifically, the level of the SGC signal is detected when the level of the SGT changes (times T1 to T8) (H: Higl, L: Low, H, H, L, L, L, H), and the SGT rise timing (Fig. Last SGT at 70`B)

The SGC level detected by the falling timing (TDC) and two groupings (HL) (HH) (LL) (LH) are used to identify four types of cylinders, the fuel supply cylinder (compression stroke or intake stroke) and the ignition timing cylinder ( Compression stroke cylinder) is recognized and the injector controls the cylinder in this timing.

As shown in Fig. 1, in the control apparatus of the present invention, when knocking occurs in the combustion of the third cylinder # 3 at time T21, the output signal of the rust sensor is operated at time T4 (see the output signal of the crank angle sensor). After the control device 8 reads out, the intake stroke injection is added, but since the compression stroke is already performed in the fourth cylinder # 4, the second cylinder continues the compression stroke injection as it is at time T22 and at the same time the intake stroke is in progress. Intake stroke control is performed at (# 2).

As a result, at the time T21, the fourth cylinder (# 4) is knocked out at time T23 only for the compression stroke injection, but in the combustion after the second cylinder (# 2), the intake / compression stroke injection is performed at the times T25 and T26. Knocking is suppressed.

Next, the control processing contents of the operation control apparatus of the internal injection type internal combustion engine according to the present invention will be described with reference to Figs. FIG. 2 is a flowchart showing the processing contents of the control device at the time TDC (falling timing of the SGT signal) in FIG. Fig. 3 is a flowchart showing the processing contents other than the control device at the time of 70 ° before the time of 70 ° B (SGT signal rising timing: TDC to the crank angle of Fig. 1) in Fig. 1. Fig. 4 is a control executed at a predetermined time. A flowchart showing the control amount calculation processing contents of the apparatus.

First, in step 101 shown in Fig. 2, the signal level of the signal SGC1 at the time TDC (SGT signal and falling timing) is read.

Next, in step 102 shown in Fig. 3, the signal level of the signal SGC2 is read out at time 70 ⁰ B (rise timing of the SGT signal). In step 103, however, the cylinder of the current internal combustion engine that is processed by the combination of the signal levels of the signals SGC 1 and SGC 2 is identified.

Subsequent to step 104, it is determined whether or not compression stroke injection is performed in the cylinder identified in step 103.

If it is determined that no compression process injection is made, the flow advances to step 109 to perform intake stroke injection. This is the same as the conventional control process, and it is determined whether or not the operating state of the internal combustion engine is in the state of compression angle injection, and in step 112, which will be described later, it is determined whether the injection process is performed in the compression stroke or the intake stroke. Output constant injection pulse and drive the injector.

On the other hand, if it is determined in step 104 that the compression stroke is being injected, the flow advances to step 105 to determine whether knocking has occurred. If it is determined that knocking has occurred in step 105 even in the extrusion stroke injection mode, the flow advances to step 106 to detect the knocking strength and calculate the amount of fuel injected into the intake stroke cylinder in accordance with the knocking strength.

In subsequent step 107, fuel is injected from the cylinder in the intake stroke in accordance with the intake stroke injection amount calculated in step 106. The flow advances to step 108, where compression stroke injection is carried out for the cylinder in which intake stroke injection is carried out in step 107. The amount of fuel to be injected in this compression stroke is the amount of heat generated by subtracting the amount of fuel in the intake stroke injection in step 107 from the amount of fuel injected in the compression stroke when no knocking has occurred. If it is determined in step 105 that no knocking has occurred, the flow advances to step 108 to perform compression stroke injection.

In the target control amount calculation routine shown in FIG. 4, the control amount controlled by the compression stroke injection process in step 108 and the intake stroke injection process in step 109 is calculated. As shown in FIG. ) Detects the load state of the internal combustion engine by the output of the throttle opening sensor 4 and detects the engine speed of the internal combustion engine 1 by the output signal SGT of the crank angle sensor 5. In the following step 112, the operating state of the internal combustion engine 1 is determined according to the engine speed of the internal combustion engine 1, and the internal combustion engine control mode is determined according to the determination result.

Specifically, injection injection mode (which mode of compression stroke injection or intake stroke injection), A / F control mode (either O₂ feedback mode or open loop control mode), driving mode (idle operation, normal operation) Whether driving or overdriving). Thereafter, in step 113, it is determined whether or not compression stroke injection is performed in accordance with the operation mode determined in step 112. In step 113, it is determined whether or not compression stroke injection is performed. If it is determined in step 113 that the compression stroke injection is performed, the flow advances to step 114 to calculate the various control target values for the use of the compression stroke component. On the other hand, when it is determined in step 113 that no compression stroke injection is performed, the flow advances to step 115 to calculate various control target values for intake stroke injection.

As described above, the present invention provides an intake stroke injection in addition to the compression stroke injection in the case of knocking caused by a special operation situation during a compression stroke injection operation in which a theoretical knocking is hardly generated in an internal combustion engine of a cylinder injection type. Knocking can be suppressed by lowering the internal temperature effectively. Therefore, it is not necessary to take into account the above-mentioned special situation (when the combustion ratio of the internal combustion engine is set high, the ignition timing is set on the advance side, the intake temperature itself is high, the volatile fuel is used, and the fuel layer diffusion is not complete). Compression ratio and ignition timing can be set and can provide a high-power and good driver internal combustion engine.

Specifically, when knocking has occurred, it is possible to suppress the self-ignition of the fuel by lowering the temperature in the barrel by the heat of vaporization by injecting a part of the fuel to be injected in the compression stroke prior to the compression stroke injection into the intake stroke. Originally, except in the above-mentioned special circumstances, knocking does not occur in the compression stroke. However, even if the operation is carried out in the special situation as described above by the change of operating conditions, the fuel is injected in the intake stroke. By suppressing the rise, it is possible to suppress the occurrence of knocking.

The amount of fuel to be injected at the intake stroke is set to an air-fuel ratio that is not burned only by the amount of injection at the intake stroke, and is generated by combustion by the total thermal effective amount of the fuel injected into the same cylinder during the compression stroke immediately after the intake stroke. It is necessary to set the output torque to be about the same as the output torque generated at the time of injection of the compression stroke in another gun just before the occurrence of knocking. Performance can be secured.

The operation control apparatus of the in-cylinder injection type internal combustion engine of the present invention includes an injector arranged to directly inject fuel into each cylinder of the internal combustion engine, an intake amount detecting means for detecting an intake amount of the internal combustion engine, and a crank angle detection means for detecting a crank angle of the internal combustion engine. And a throttle valve opening degree detecting means for detecting the opening degree of the throttle valve, a cylinder identifying means for identifying the cylinder to be burned, a rust detecting means for detecting knocking of the internal combustion engine, an intake air amount detecting means, a crank angle detecting means or a throttle characteristic The fuel injection amount of the internal combustion engine is calculated according to the detection signal of the valve opening detection means, and the fuel injection amount is transmitted as an electric signal to the injector and the fuel injection control of the internal combustion engine is provided. If knocking occurs in the operating state, fuel is injected into the barrel on the intake stroke. In this case, it is possible to suppress the knocking by lowering the temperature in the cylinder by injecting fuel in the intake stroke in front of the compression stroke even when knocking occurs because the operation situation becomes special during the compression stroke injection operation that is hard to knock. have.

Therefore, according to the control device of the present invention, it is possible to assume a special driving situation and to set the performance of the internal combustion engine at a high level without sacrificing the characteristics such as output fuel efficiency in a normal driving state.

In addition, according to the knocking condition, the amount of fuel injected into the cylinder in the intake stroke is variably controlled, so knocking can be effectively suppressed.

In addition, the amount of fuel injected into the cylinder in the intake stroke is set so that the air-fuel ratio does not ignite in the cylinder, so knocking can be effectively suppressed.

In addition, the amount of fuel injected into the cylinder by the intake stroke is the amount of fuel injected by the compression stroke when the output torque obtained by burning the fuel of the sum of the fuel amount injected into the cylinder in the compression stroke following the intake stroke does not occur. It is characterized in that it is set to be approximately equal to the output torque according to, so that the driver belliness of the internal combustion engine can be improved.

Claims (3)

An injector arranged to directly inject fuel into each cylinder of the internal combustion engine, an intake amount detecting means for detecting the intake amount of the internal combustion engine, a crank angle detection means for detecting the crank angle of the internal combustion engine, and a throttle valve opening for detecting the opening degree of the throttle valve. The internal combustion engine in accordance with a detection signal and a cylinder identification means for identifying a cylinder to be burned, a rust detection means for detecting knocking of an internal combustion engine, an intake air amount detecting means, the crank angle detecting means or a throttle valve opening degree detecting means. And an operation control device which calculates the fuel injection amount of the fuel injection and transmits the fuel injection amount to the injector as an electric signal and controls the fuel injection of the internal combustion engine. When knocking occurs in the operation state where fuel injection is performed in the compression stroke, In the cylinder injection type internal combustion engine which injects fuel into the cylinder in the intake stroke at the time of knocking. Operation control device The method of claim 1 Operation control device of the in-cylinder injection type internal combustion engine which variably controls the amount of fuel injected into the canister in the intake stroke according to the state of the knocking. The method of claim 1 Operation control apparatus of the in-cylinder injection type internal combustion engine which is set so that the fuel quantity injected in the inhalation stroke may be an air-fuel ratio which does not ignite in the inside of the cylinder.