JP2003262147A - Start control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quicken starting of an internal combustion engine by quickening supply of fuel after a cylinder is discriminated upon starting the internal combustion engine. <P>SOLUTION: This start control device of the internal combustion engine discriminates the cylinder from a turning angle position when an engine is rotated from a suspension condition, and controls the supply of the fuel of each cylinder based on discrimination results. This device comprises a predicting means (step S4) for predicting an operating condition when the engine is rotated from the suspended turning angle position to the turning angle position for supplying the fuel to a predetermined cylinder; and a calculation means (step S5) for calculating a control volume for supplying the fuel to the cylinder based on the results predicted by the prediction means. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for starting an internal combustion engine such as a diesel engine.

[0002]

2. Description of the Related Art There is known an internal combustion engine configured to supply fuel to each cylinder for the purpose of improving power performance, improving fuel efficiency, and purifying exhaust gas. In this type of internal combustion engine, fuel is injected into the cylinder, the intake port, etc. based on the timing at which the piston reaches the compression top dead center in each cylinder, the timing of the intake stroke, and the like.

Such fuel injection control is similarly performed even when the internal combustion engine is started, and reaches compression top dead center when the internal combustion engine is cranked (motored) by a starter motor or the like. Fuel is injected into a cylinder, and combustion energy based on the fuel is used to cause the internal combustion engine to rotate independently. When the internal combustion engine is stopped, it is not possible to determine the state of each cylinder, so
Cylinder discrimination, that is, the cylinder reaching the compression top dead center is discriminated by a signal output based on the rotation when the internal combustion engine is motorized for starting.

For example, in a four-cycle engine, the camshaft makes one revolution while the crankshaft makes two revolutions.
Therefore, if a signal is output each time each shaft makes one rotation, whichever one of them becomes the compression top dead center even in a four cylinder engine in which the pistons reach the top dead center in two cylinders at the same time. It is possible to determine whether the position is the rotational angle position. However, if the cylinders at the time of starting are discriminated in this way, the crankshaft needs to rotate twice, and the time until the complete explosion is reached may be delayed, which may cause a delay in starting. .

In order to eliminate such inconvenience, there is disclosed a device configured to control the engine stop position so that the cylinder can be identified immediately after motoring.
891. The invention described in this publication determines the cylinder at the compression top dead center from the crank angle of the engine, and when the engine is stopped by operating the ignition switch, a predetermined cylinder based on the determined compression top dead center is determined. It is configured to stop the fuel from the cylinder. In the invention described in this publication, the cylinder that starts stopping the fuel can be specified, so that the crank angle region when the engine is stopped can be specified, and as a result, the crank angle region closest to the rotation direction of the engine from the stopped crank angle range can be specified. It is said that the cylinder discrimination can be accelerated by marking the position for the cylinder discrimination.

[0006]

According to the invention described in the above publication, it is possible to quickly determine the cylinder. However, in order to inject the fuel into the determined cylinder and surely start the fuel, it is necessary to optimize the parameters for the fuel injection control such as the injection timing and the injection amount. For example, if the injection timing differs by about 10 degrees or more in crank angle, there is a high possibility that the engine will fail to start, and if the fuel injection amount is increased in order to ensure a reliable start, fuel consumption will deteriorate. In particular,
The demand for quick and reliable start is strong in so-called eco-run control that automatically stops and automatically starts the internal combustion engine in order to avoid unnecessary idling and improve fuel efficiency, giving priority to startability and increasing the fuel injection amount. Therefore, the original purpose of controlling automatic stop and automatic start cannot be achieved.

Therefore, even if the stop position of the engine can be specified as described in the above publication, at the time of restarting after stop, the timing of fuel injection and the engine speed for determining the timing, and further The control amount such as the fuel injection amount is calculated and obtained. Since the calculation also involves transmission of data, there is an unavoidable time delay until the fuel is actually injected, and in the end,
Even if the cylinder can be quickly identified at the time of starting after the stop, the fuel cannot be injected immediately after the identification of the cylinder, which may delay the start.

The present invention has been made by paying attention to the above technical problems, and it is possible to quickly start the internal combustion engine with the cylinder discrimination and the fuel supply control based on the result of the cylinder discrimination. An object is to provide a control device.

[0009]

In order to achieve the above-mentioned object, the invention of claim 1 discriminates the cylinder from the rotational angle position when the cylinder is rotated from the stopped state, and the discrimination result In a start control device for an internal combustion engine that controls fuel supply for each cylinder based on the following, predicts an operating state when rotating from a stopped rotation angle position to a rotation angle position for supplying fuel to a predetermined cylinder The starting control device is characterized by comprising: a predicting means for performing a calculation and a calculating means for calculating a control amount for supplying fuel to the cylinder based on a prediction result by the predicting means.

As described in claim 2, the predicting means predicts the rotational speed when the engine is rotated for starting from the rotational angle position at which it is stopped to the rotational angle position at which cylinder discrimination is performed. It can be a means.

Therefore, in the invention of claim 1 or the invention of claim 2, when the internal combustion engine is rotated for starting and fuel is supplied, the control amount related to the supply of the fuel is the rotational speed of the internal combustion engine. It is calculated during the stop based on the result of predicting the operating state such as. As a result, the fuel can be immediately supplied at the time when the fuel should be supplied after the start. In other words, it is possible to prevent a substantial delay in starting due to the inability to obtain the control amount related to the fuel supply, and to quickly start the internal combustion engine.

The invention according to claim 3 is the invention according to claim 1 or 2, further comprising an electric motor for rotating the internal combustion engine for starting, and a power supply for supplying electric power to the electric motor. Is a starting control device characterized by being configured to make a prediction based on the voltage of the power source or a detection value related to the voltage.

Therefore, in the third aspect of the present invention, since the data affecting the behavior of the internal combustion engine, such as the torque of the electric motor that rotates the internal combustion engine for starting, is reflected in the prediction, the accuracy of the prediction is improved.

According to the invention of claim 4, in the invention of claims 1 to 3, the detected value used for the prediction includes the temperature of the internal combustion engine or a detected value related to the temperature. The starting control device is characterized in that

Therefore, in the invention of claim 4, the temperature of the internal combustion engine is reflected in the prediction. That is, when the temperature of the internal combustion engine is low, the friction is large, and conversely, when the temperature is high, the friction is small.Therefore, after the internal combustion engine is rotated for starting, the time of cylinder discrimination or the time of fuel supply. Since the rotational speed of No. 1 varies depending on the temperature of the internal combustion engine, the operating conditions such as the rotational speed of the internal combustion engine at the time of cylinder discrimination or fuel supply can be accurately predicted in the invention of claim 4.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described based on specific examples. First, the internal combustion engine to which the present invention is applied will be described. The internal combustion engine according to the present invention is an internal combustion engine that can be automatically stopped and automatically restarted by supplying or stopping fuel or air, or turning on or off ignition. Examples of the engine include a diesel engine, a gasoline engine, and a gas-fueled engine. FIG. 3 shows a diesel engine as an example of the internal combustion engine (engine) 1. The example shown here is a so-called direct injection engine in which fuel is directly injected into the cylinders 2, 3, 4, and 5. , An exhaust gas recirculation mechanism (EGR) for purifying exhaust gas. Note that, from the left of FIG. 3, the cylinders are # 1 cylinder 2, # 2 cylinder 3, # 3 cylinder 4, and # 4 cylinder 5, and the order of reaching compression top dead center is #
1 cylinder 2, # 3 cylinder 4, # 4 cylinder 5, # 2
The cylinder 3.

That is, injectors 6, 7, for injecting fuel at high pressure into the cylinders 2, 3, 4, 5 respectively.
8 and 9 are provided for these injectors 6,
7, 8 and 9 are connected to a common rail 10 which temporarily stores the fuel pressurized to a high pressure. Further, the glows 11, 12, 1 are respectively provided in the cylinders 2, 3, 4, 5.
3, 14 are provided.

The fuel pump 15 for pressurizing the fuel is a so-called plunger type pump, and as shown in FIG. 4, it is pressed by an elliptical cam 17 which rotates integrally with the cam shaft 16 and by a return spring 18. It is designed to move back. Therefore, the camshaft 16 makes one rotation of two rotations of the crankshaft (not shown), and the elliptical cam 17 presses the plunger at both ends in the long axis direction. ), The fuel is sucked and pumped once every 360 ° CA.

An intake manifold 19 for distributing and supplying intake air to each of the cylinders 2, 3, 4, 5 is connected to a compressor 21 in an exhaust type supercharger 20.
From this compressor 21 to intake manifold 1
An intercooler 22 that cools intake air that has been pressurized and has an increased temperature, and an intake throttle valve 23 that controls the amount of intake air are provided in the intake pipe line reaching 9. The intake throttle valve 23
Are configured to be electrically controlled by an actuator (not shown) such as a motor.

On the other hand, the exhaust manifold 24 connected to the exhaust ports of the cylinders 2, 3, 4, 5 is connected to the exhaust turbine 25 of the supercharger 20. Further, the exhaust turbine 25 is communicated with a catalytic converter 26 having an exhaust purification catalyst.

An exhaust gas recirculation pipe line 27 for guiding a part of the combustion exhaust gas generated in each of the cylinders 2, 3, 4, 5 to the intake manifold 19 is provided. An EGR cooler 28 for cooling and an EGR valve 29 for controlling the flow rate of exhaust gas are provided in this order from the side of the exhaust manifold 24.

Further, like the normal engine, the engine 1 must be forcibly rotated to the complete explosion rotation speed by an external force at the time of starting, and a starter 30 is attached as a rotation drive mechanism for that purpose. This starter 30
May have an appropriate configuration. For example, a pinion gear (not shown) may be moved forward by a start signal to mesh (that is, engage) with a ring gear (not shown) in the engine 1, and in that state. A configuration in which the engine 1 is rotated can be adopted.

A capacitor 31 is provided as a power source for the starter 30. The capacitor 31 stores electric charge and supplies electric power to the starter 30 as needed, and has the same function as a storage battery. A generator 32 is provided as a device for supplying charges to the capacitor 31.

The generator 32 is always connected to a predetermined output member of the engine 1 or an output member of a transmission (not shown) that rotates when the vehicle equipped with the engine 1 is running. Therefore, this generator 32
Not only receives the torque from the engine 1 to rotate, but is also rotated by the inertial force of the vehicle when the vehicle decelerates to regenerate energy.

The generator 32 is connected to the capacitor 3 via an appropriate control device (not shown) such as an inverter.
Connected to 1. Therefore, the energy regenerated when the vehicle is decelerated is stored in the capacitor 31. Therefore, if the amount of regenerated energy is sufficient, the voltage of the capacitor 31 will be high, but if the amount of regenerated energy is small, the voltage of the capacitor 31 will be relatively low.

The engine 1 is automatically stopped when a predetermined condition such as a condition that the engine 1 is stopped and a braking operation is established, and then the stopping condition such that the braking operation is released is not established. Thus, so-called eco-run control that is automatically restarted is possible. Electronic control unit for engine (EE)
CU) 33 and an electronic control unit for eco-run (ECO-EC
U) 34 are provided.

The electronic control units 33 and 34 are mainly composed of a microcomputer,
The engine electronic control unit 33 is configured to perform an operation based on the input data and control the operating state of the engine 1. Specifically, when a start request is made, the starter 30 is driven to change the gear to the engine 1
Side gear and cranking the engine 1 and performing cylinder discrimination at the time of starting, controlling the fuel injection timing and injection amount, and further, during running, based on the acceleration / deceleration request based on the fuel injection amount. Of the intake throttle valve 23 and EGR
It is configured to control the opening degree of the valve 29 and further control the supercharging pressure by the supercharger 20 based on the acceleration / deceleration request.

The eco-run electronic control unit 34 performs a calculation based on the input data, determines whether the stop condition or the start condition of the engine 1 is satisfied, and the electronic control unit 33 for the engine determines based on the result of the determination. On the other hand, a stop request or a start request for the engine 1 is output. The stop condition is, for example, that the vehicle speed is determined to be zero and that the brake operation is performed. Further, the starting condition is that any one of the contents of the stopping condition is not satisfied such as when the brake operation is released. If there is a stop request or a start request, the electronic control unit for engine 33 executes control of stopping or starting the engine 1 in accordance with the request, and if there is no such request, the accelerator opening degree is set. It is configured to control the output of the engine 1 (more specifically, the fuel injection amount) according to a representative drive request amount.

In order to perform these controls, a detection signal from a voltage sensor 35 for detecting the voltage of the capacitor 31 is input to the engine electronic control unit 33, and a signal from a crank angle sensor 36 and a crank angle reference position are also input. Each signal from the sensor 37 is input. Further, although not shown in particular, another appropriate signal such as a vehicle speed signal is input to one of the electronic control units 31 and 34.

The crank angle sensor 36 is a sensor for detecting a rotation angle of a crank shaft (not shown) in the engine 1 and for detecting a rotation speed (rotation speed) of the engine 1 using the detection signal. As shown in FIG. 5, the timing rotor 38 is rotated by one rotation of the crankshaft, and the pickup 39 is arranged at a predetermined position on the outer peripheral side of the timing rotor 38. The timing rotor 38 has a predetermined angle (for example, 10 degrees) on the outer peripheral edge.
It is a disk-shaped or gear-shaped member in which protrusions or teeth are formed for each of them, and the protrusions or teeth are partly missing, and that part is a so-called tooth-missing portion 40. The pickup 39 is a so-called electromagnetic pickup, and is configured to output a pulse signal each time the protrusions or teeth of the timing rotor 38 approach and then move away.

Therefore, the crank angle sensor 36 is
The rotation angle of the crankshaft can be detected as the angle from the toothless portion 40. More specifically, in the example of the 4-cylinder 4-cycle engine, the pistons in the two cylinders (for example, the first burning # 1 cylinder 2 and the third burning # 4 cylinder 5) simultaneously reach the top dead center. Since one of them reaches the top dead center in the compression stroke and the other becomes the top dead center in the exhaust stroke, #
In order that the compression top dead center of one cylinder 2 is at a predetermined angle (for example, 120 degrees) from the toothless portion 40, the toothless portion 40
The relative position between the pickup 39 and the pickup 39 is set.

On the other hand, the crank angle reference position sensor 3
Reference numeral 7 denotes a sensor for giving a reference position of an angle during which the crankshaft makes two revolutions as the crankshaft makes two revolutions and completes one cycle. As shown in FIG. A rotating member that makes one revolution while the crankshaft makes two revolutions (for example, a camshaft timing pulley)
One protrusion 42 is formed on the outer peripheral portion of 41, and the protrusion 4
A pickup 43 that outputs a pulse signal in response to 2 is arranged on the outer peripheral side of the rotating member 41. The relative position between the protrusion 42 and the pickup 43 is set at a position where the pickup 43 detects the protrusion 42 at a crank angle (CA) of 25 degrees before the compression top dead center of the # 1 cylinder 2. Has been done.

Therefore, these sensors 36 and 37 can detect the angular position of the crankshaft during two revolutions and the stroke of each cylinder. In the above example, the output signals of the sensors 36 and 37 are detected almost at the same time to determine that the state is 90 ° CA before the compression top dead center of the # 1 cylinder 2, and the crank angle sensor When only the output signal of 36 is detected, the compression top dead center of the # 4 cylinder 5 is 90 ° CA.
The previous state is determined.

As described above, the engine 1 targeted by the present invention uses the signal (Ne signal) of the crank angle sensor 36.
And crank angle reference position sensor 37 signal (G1 signal)
Since the cylinder discrimination is performed based on the above, it is possible to discriminate the cylinder without fail if the crankshaft makes two revolutions from the stopped state, but depending on the stop angle position of the crankshaft, the cylinder can be discriminated immediately after starting to rotate. . Specifically, if the engine 1 is stopped in a state in which the compression top dead center of the # 1 cylinder 2 has passed by about 90 ° CA, when the engine 1 rotates by approximately 180 ° CA, that is, the # 4 cylinder 5
Cylinder can be discriminated at a time point 90 ° CA before the compression top dead center of No. 4 or the compression top dead center of the # 4 cylinder 5 is 90 ° CA.
If the engine 1 is stopped in a state where it has passed a certain degree, it is possible to determine the cylinder at the time when the engine has rotated by approximately 180 ° CA, that is, at the time 90 ° CA before the compression top dead center of the # 1 cylinder 2.

The control device of the present invention is configured to perform the start control as follows by utilizing the cylinder discrimination function when starting from the above specific stop position.
FIG. 1 is a flowchart for explaining the control example. First, it is determined whether or not the engine 1 is stopped by so-called eco-run control (step S1).
As described above, the eco-run control automatically stops the engine 1 when a predetermined condition is satisfied while the vehicle is stopped, and the stop condition of the engine 1 is not satisfied in that condition. This is the control for automatically starting the engine 1.

If a positive determination is made in step S1, the voltage applied to the starter 30, that is, the output voltage of the capacitor 31, is read, and the engine water temperature is read (step S2). These capacitors 31
The output voltage and the engine water temperature are detected values used for predicting the operating state of the engine 1 at the time of cylinder discrimination or at the time of first fuel injection after starting.

Next, when the engine 1 is cranked by the starter 31, the time from the position where the engine 1 is stopped until the cylinder discrimination is performed is calculated (step S3). This can be obtained based on the engine water temperature related to the friction of the engine 1 and the output voltage (power supply voltage) of the capacitor 31 related to the torque for cranking.

Further, the engine speed (engine speed) at the time of cylinder discrimination is predicted (step S4). This can be performed by, for example, previously obtaining the rising state of the engine speed when the starter 31 is driven with a predetermined voltage and then determining the engine speed that will be reached after the time calculated in step S3. Then, the fuel injection amount and injection timing (injection timing) are determined based on the predicted engine speed (step S5).

The calculations and predictions of steps S2 to S5 described above are executed while the engine 1 is stopped, and the fuel injection amount and injection timing obtained in step S5 are held (stored). When there is a request for restarting the engine 1 based on the eco-run control (step S6), the cylinder is discriminated when the engine 1 is cranked by the starter 31 and rotated by a predetermined angle, and the fuel is immediately fueled based on the discrimination result. Is ejected (step S7). The control amount related to the fuel injection, that is, the injection amount and injection timing,
Since it is already required before the engine 1 is started, when the cylinder is discriminated, the fuel is injected at a predetermined timing immediately after that. That is, there is no delay in fuel injection.

This will be described with reference to the drawings. In FIG. 2, the engine 1 is stopped in a state where the compression top dead center of the # 1 cylinder 2 has passed by about 90 ° CA, and cranking is performed from that state. , # 4 The cylinder is discriminated at an angular position 90 ° CA before the compression top dead center of the cylinder 5. Immediately after 90 ° CA, the # 4 cylinder 5 reaches the compression top dead center. Therefore, according to the control device of the present invention, the fuel injection to the # 4 cylinder 5 can be started. This is because the control amount related to fuel injection has already been obtained.

On the other hand, in the conventional apparatus which calculates the control amount related to the fuel injection after the cylinder discrimination, the control amount related to the fuel injection is calculated within a short period of 90 ° CA after the cylinder discrimination. , The injectors 6, 7, 8 and 9 cannot be controlled, and as a result, even if the fuel is injected earliest, it waits until the compression top dead center of the # 2 cylinder 3 after further rotating by 180 ° CA. Must-have. That is, there is a time delay in fuel injection.

If a negative determination is made in step S1, the ignition switch (not shown)
The normal engine start control based on the turning on of is performed (step S8).

The relationship between the above embodiment and the present invention will be briefly described. The functional means of step S4 shown in FIG. 1 corresponds to the predicting means of the present invention, and step S5.
The functional means of is equivalent to the arithmetic means of the present invention.

It should be noted that the present invention is not limited to the above specific examples, and the starter for starting the internal combustion engine may also serve as a generator, and the power source is a secondary battery instead of the above capacitor. You may use. Further, the sensor for detecting the engine rotation angle position and for performing the cylinder discrimination is not limited to the crank angle sensor and the crank angle reference position sensor described above. It may be configured to detect the angular position and determine the cylinder.

Further, in the above-mentioned specific example, an example in which the operating state of the engine at the time of cylinder discrimination is predicted is given, but the point of the present invention is that the fuel supply control is properly performed immediately after the cylinder discrimination. Thus, the present invention predicts the operating state of the engine. Therefore, the operating state of the internal combustion engine at the time when the compression top dead center is reached in any of the cylinders immediately after the cylinder determination may be performed. Furthermore, in the above example,
Although the power supply voltage and the engine water temperature were mentioned as the data for prediction, data other than these may be used, and the values related to these data may be used to indirectly determine the power supply voltage and the engine water temperature. It may be incorporated into the control. Further, the control amount related to the fuel supply may include a control amount other than the fuel injection amount and the fuel injection timing.

[0046]

As described above, according to the invention of claim 1 or the invention of claim 2, when the internal combustion engine is rotated for starting and fuel is supplied, it relates to the supply of fuel. Since the control amount is calculated during the stop based on the result of predicting the operating state such as the rotation speed of the internal combustion engine,
After the start, when it is time to supply fuel, fuel can be supplied immediately. In other words, it is possible to prevent a substantial delay in starting due to the inability to obtain the control amount related to the fuel supply, and it is possible to quickly start the internal combustion engine.

According to the invention of claim 3, claim 1
Alternatively, in addition to the effect obtained by the invention of 2, the prediction accuracy is improved because the data that affects the behavior of the internal combustion engine, such as the torque of the electric motor that rotates the internal combustion engine for starting, is reflected in the prediction. As a result, the internal combustion engine can be started quickly and reliably.

According to the invention of claim 4, since the temperature of the internal combustion engine is reflected in the prediction, the accuracy of prediction of the operating state of the internal combustion engine at the time of cylinder discrimination or fuel injection is improved, and the internal combustion engine is improved. The engine can be started quickly and reliably.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining a control example executed by a control device of the present invention.

FIG. 2 is a time chart showing an example of the fuel injection timing after starting according to the present invention and a conventional example.

FIG. 3 is a block diagram schematically showing a control system of an internal combustion engine targeted by the present invention.

FIG. 4 is a diagram schematically showing an example of a fuel pump.

FIG. 5 is a schematic diagram showing an example of a crank angle sensor.

FIG. 6 is a schematic diagram showing an example of a crank angle reference position sensor.

[Explanation of symbols]

1 ... Engine, 2, 3, 4, 5 ... Cylinder, 30 ...
Starter, 31 ... Capacitor, 33 ... Engine electronic control unit (E-ECU), 34 ... Eco-run electronic control unit (ECO-ECU), 36 ... Crank angle sensor, 37 ... Crank angle reference position sensor.

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Claims (4)

[Claims] 1. A start control device for an internal combustion engine, which determines a cylinder based on a rotational angle position when the cylinder is rotated from a stopped state, and controls fuel supply for each cylinder based on the determination result. Prediction means for predicting an operating state when rotating from a rotation angle position to a rotation angle position for supplying fuel to a predetermined cylinder, and for supplying fuel to the cylinder based on the prediction result by the prediction means. A starting control device for an internal combustion engine, comprising: a calculation unit that calculates a control amount. 2. The predicting means is means for predicting a rotational speed when rotating for starting from a stopped rotational angle position to a rotational angle position where cylinder discrimination is performed. Item 1. A start control device for an internal combustion engine according to Item 1. 3. An electric motor for rotating the internal combustion engine for starting, and a power source for supplying electric power to the electric motor, wherein the predicting means is based on a voltage of the power source or a detection value related to the voltage. The starting control device for an internal combustion engine according to claim 1 or 2, wherein the starting control device is configured to make a prediction. 4. The detection value used for the prediction includes
4. The start control device for an internal combustion engine according to claim 1, wherein a temperature of the internal combustion engine or a detected value related to the temperature is included.