JP6579852B2 - Start control device and start control method for internal combustion engine - Google Patents

Description

  The present invention relates to a start control device and a start control method for an internal combustion engine, and is particularly suitable for application to a start control device and a start control method for controlling the start timing of an internal combustion engine.

  Conventionally, when starting an internal combustion engine (engine), the driver turns on an ignition switch to operate the starter. At this time, an ECU (Electronic Control Unit) that controls the operation of the engine performs cranking by a starter and performs cylinder discrimination. Cylinder discrimination means that each cylinder is in any one of an intake process, a compression process, an expansion process, and an exhaust process, and which cylinder injects fuel at an appropriate timing.

  After discriminating the cylinder, the ECU immediately injects fuel into the cylinder in a process in which fuel can be injected (a compression process in the case of a gasoline engine and an expansion process in the case of a diesel engine) to cause an initial explosion. Thus, the ECU can start the engine early after determining the cylinder. Techniques for starting the engine at an early stage are described in Patent Documents 1 and 2, for example.

  In Patent Document 1, in addition to the cam pulse generated in synchronization with the cylinder discrimination period, another cam pulse is also generated during the period from the cylinder discrimination period until a specific part (missing tooth portion) of the next crank rotor is detected. Thus, a configuration in which three protrusions are installed on the cam rotor is disclosed. These three protrusions are installed so as to generate cam pulses at a timing at which fuel can be injected into all the cylinders.

  According to this Patent Document 1, when a cam pulse is detected before a missing tooth portion is detected (before cylinder discrimination), fuel injection is performed on all cylinders, and then the missing tooth portion is detected. After (after cylinder discrimination), fuel is immediately injected into the cylinder that first becomes the compression top dead center, thereby shortening the time from cranking to the first ignition and starting the engine well.

  Further, in Patent Document 2, the crank pulse in which pulses of equal intervals are formed except for the missing tooth portion and the eight pulses are all different in interval, and three pulses are formed every 90 °. A configuration for discriminating a cylinder using a cam pulse is disclosed. Specifically, the interval between two consecutive cam pulses is determined based on the number of crank pulses formed therebetween, and the cylinder is determined based on the determined cam pulse interval.

  According to Patent Document 2, the time required for cylinder discrimination can be shortened by discriminating a cylinder by detecting two cam pulses.

Japanese Patent Laid-Open No. 2000-240489 JP 2013-133721 A

  However, both of the techniques described in Patent Documents 1 and 2 attempt to start the engine early by reducing the time required for cylinder discrimination, and noise generated by starting the engine early. No consideration is given to noise and vibration (NV). That is, as a result of starting the engine early, there is a problem that a larger NV is generated.

  NV depends on the difference in engine speed before and after the first explosion. For example, the engine speed by the starter before the first explosion is 150 rpm, the engine speed after the first explosion is 800 rpm, and the engine speed before the first explosion is 300 rpm. In the case of 800 rpm, the difference is smaller and the NV is smaller when changing from 300 rpm to 800 rpm.

  For this reason, the initial explosion is performed in a state where the engine speed by the starter is stable (for example, the speed increased from 150 rpm to 300 rpm), thereby reducing the difference from the engine speed (for example, 800 rpm) after the first explosion. NV can be suppressed.

  In order to simply eliminate NV, it is only necessary to delay the initial explosion by injecting fuel after a certain period of time has elapsed since the cylinder was identified. In this case, however, there is another problem that engine startup is always delayed. Arise. In addition, if the period for delaying the first explosion is fixed, NV may not be suppressed as expected depending on the state of the vehicle, such as the engine speed of the starter before the first explosion is difficult to increase.

  The present invention has been made in consideration of the above points, and proposes a start control device and a start control method capable of appropriately controlling the start timing of an engine in consideration of noise and vibration.

  In order to solve such a problem, according to the present invention, in a start control device that controls the operation at the start of an internal combustion engine, the rotation angle of the crank detected by the crank position sensor and the cam rotation detected by the cam position sensor. An interface for inputting a rotation angle, a processor for determining the state of each cylinder based on the rotation angle input by the interface, and determining for each cylinder the timing at which fuel should be injected based on the determined state of each cylinder; And the processor counts the number of times that it is determined that it is time to inject fuel for each cylinder, and injects fuel into the cylinder whose count value has become larger than a predetermined value for the first time. The engine is controlled to start.

  According to the present invention, it is possible to appropriately control the engine start timing in consideration of noise and vibration.

It is a block diagram of an engine. It is a flowchart of a start control process.

(1) Overall Configuration FIG. 1 shows a block diagram of the engine 1 in the present embodiment. The engine 1 includes various sensors 11 to 13, an ignition switch 14, an ECU (Electronic Control Unit) 15, an actuator 16, and the like. Here, the various sensors are a crank position sensor 11, a cam position sensor 12, and a water temperature sensor 13.

  The crank position sensor 11 is disposed opposite to the outer periphery of a crank rotor that is integrally fixed to the crankshaft and rotates. On the outer periphery of the crank rotor, a plurality of teeth are formed for each predetermined angle (for example, 6 ° CA: Crank Angle). Further, a missing tooth portion (for example, 18 ° CA) in which some teeth are not formed is formed. The missing tooth portion is provided to determine the reference position of the crank rotor.

  The crank position sensor 11 detects the presence / absence of a tooth each time the crank rotor rotates 6 ° CA, and generates a pulse that rises when the tooth is detected. Further, a pulse that falls when a tooth passes or a missing tooth portion is detected is generated, and a pulse train composed of these high and low rectangular waves is output to the ECU 15 as a crank pulse. The ECU 15 calculates the rotation speed of the engine 1 based on the crank pulse.

  The cam position sensor 12 is disposed opposite to the outer periphery of a cam rotor that is integrally fixed to the camshaft and rotates. Concavities and convexities or teeth are formed on the outer periphery of the cam rotor. Like the crank position sensor 11, the cam position sensor 12 detects the presence or absence of concavities and convexities or teeth every time the cam rotor rotates, and generates a pulse train composed of rectangular waves. This is output to the ECU 15 as a cam pulse. The ECU 15 determines the cylinder based on the cam pulse and the crank pulse described above.

The water temperature sensor 13 is installed in the vicinity of the cylinder, detects the cooling water temperature of the engine 1, and outputs it to the ECU 15. Based on this coolant temperature, the ECU 15 determines whether or not the engine 1 should be started early as will be described later. The engine 1 includes, in addition to these sensors 11 to 13, for example, an accelerator opening sensor, an air flow sensor, an O ₂ sensor, and the like, but description thereof is omitted here.

  The ignition switch 14 is provided on a power supply line for supplying power to the ECU 15. When the ignition switch 14 is turned on, predetermined power is supplied to the ECU 15. The ignition switch 14 is turned on / off by, for example, inserting a key into a keyhole and rotating the ignition switch 14 by a predetermined angle or pressing a predetermined button.

  The ignition switch 14 generates a signal indicating a request for starting the engine 1 and outputs the signal to the ECU 15 when, for example, the key is further rotated or a predetermined button is pressed. When the ECU 15 inputs a start request from the ignition switch 14, the ECU 15 rotates the starter. The ECU 15 starts the engine 1 by injecting fuel at an appropriate timing after determining the cylinder.

  The ECU 15 includes a processor 151, a storage unit 152, an interface 153, and the like. When the ignition switch 14 is turned on and power is supplied, the processor 151 performs overall control of the operation of the engine 1 in cooperation with various programs stored in the storage unit 152. At this time, the processor 151 generates a control signal based on various signals input through the interface 153, and outputs the generated control signal through the interface 153.

  As described above, the ECU 15 in the present embodiment calculates the rotation of the engine 1 based on the crank pulse from the crank position sensor 11, and determines the cylinder based on the crank pulse and the cam pulse from the cam position sensor 12. Determine. Further, based on the water temperature from the water temperature sensor 13, it is determined whether or not to start the engine 1 at an early stage. Details of the processing will be described later (FIG. 2).

  The actuator 16 includes an injector 161, an igniter 162, and the like. The injector 161 is a fuel injection device that is installed corresponding to each cylinder and injects fuel into a combustion chamber formed inside each cylinder. The injector 161 injects an appropriate injection amount into the combustion chamber at an appropriate injection timing based on a control signal from the ECU 15.

  The igniter 162 determines an appropriate ignition timing based on a control signal from the ECU 15 for the ignition plug installed corresponding to each cylinder. The spark plug ignites the fuel / air mixture supplied to the combustion chamber at the ignition timing determined by the igniter 162, and starts the engine 1 by burning the mixture.

(2) Flowchart FIG. 2 shows a flowchart of the start control process in the present embodiment. The start control process is executed in cooperation with the processor 151 of the ECU 15 and various programs stored in the storage unit 152 when a request for starting the engine 1 is input to the ECU 15. For convenience of explanation, in the following explanation, the processing subject will be explained as the ECU 15.

  First, the ECU 15 inputs a start request for the engine 1 (SP1), and determines whether or not the input start request is a start request from an idle stop (SP2).

  For example, when the engine 1 start request input in step SP1 is a start request from another device such as an idle stop ECU, the ECU 15 determines that the start request is from an idle stop (SP2: Y). In this case, the ECU 15 performs control so as to perform normal engine start (SP3), and ends this process.

  The normal engine start refers to a start in which fuel is injected for the first explosion immediately after the cylinder is determined without considering noise and vibration (NV). When starting the engine 1 from an idle stop, the driver usually wants to start the engine 1 early. Therefore, in this case, the engine 1 is started early by a normal engine start.

  On the other hand, when the start request of the engine 1 input in step SP1 is a start request from the ignition switch 14, for example, the ECU 15 determines that it is not a start request from an idle stop (SP2: N). In this case, the ECU 15 proceeds to step SP4.

  In step SP4, the ECU 15 inputs a signal indicating the water temperature from the water temperature sensor 13, and determines whether or not the current water temperature is higher than a predetermined temperature T1 (SP4). If a negative result is obtained in this determination (SP4: N), the ECU 15 performs control so as to perform normal engine start (SP3), and the process is terminated.

  When the water temperature is low, that is, when the outside air temperature is low, the driver usually desires to start the engine 1 early. Therefore, in this case, the engine 1 is started early by a normal engine start.

  On the other hand, if a positive result is obtained in the determination at step SP4 (SP4: Y), the ECU 15 determines whether or not the cranking is currently being performed (SP5). When a negative result is obtained in this determination (SP5: N), that is, when cranking is not being performed, the ECU 15 operates the starter to perform cranking.

  On the other hand, when an affirmative result is obtained in the determination of step SP5 (SP5: Y), that is, when cranking is being performed, the ECU 15 causes the count value S1 of the fuel injection timing in each cylinder to be greater than a predetermined value C1. It is determined whether it is larger (SP6).

  The fuel injection timing is a timing at which the ECU 15 determines that the fuel should be injected after determining the cylinder based on the crank pulse and the cam pulse, and is different for each cylinder. The count value S1 of the fuel injection timing is a value obtained by counting the number of times that it is determined that the fuel should be injected for each cylinder. The count is counted by an internal counter of the ECU 15.

  For example, in the case of a four-cylinder engine, when the fuel injection timing comes to the second cylinder after the first cylinder, the fuel injection timing of the second cylinder is the compression top dead center (TDC) in the first cylinder. : Top Dead Center) is set after the arrival timing and before the compression top dead center arrival timing in the second cylinder.

  The ECU 15 in the present embodiment, for example, even when the count value S1 is incremented by “+1” from “0” to “1”, that is, even when the appropriate timing for injecting fuel after cylinder discrimination is counted for the first time, When the predetermined value C1 is “1”, S1> C1 is not satisfied, so that fuel injection is not performed on the cylinder that can inject fuel most recently. This can delay the timing of the first explosion.

  Note that the value of the predetermined value C1 can be arbitrarily set. For example, by setting C1 to “0”, it is possible to inject fuel into the cylinders counted for the first time at an appropriate timing for injecting fuel after cylinder discrimination. Conversely, if C1 is set to a large value such as “5”, the time until S1> C1 is satisfied can be lengthened.

  The predetermined value C1 may be set within a predetermined range by the driver, or may be set only by a specific person such as a mechanic. When the driver can arbitrarily set, giving priority to early start of the engine 1 or conversely delaying the start to sufficiently suppress NV can be flexibly handled according to the driver's preference. it can.

  Next, the ECU 15 determines whether or not the rotational speed Ne1 of the engine 1 is greater than a predetermined rotational speed C2 (SP7). The engine speed Ne1 is specifically the engine speed of the crankshaft per unit time.

  If a positive result is obtained in the determination of step SP7 (SP7: Y), the ECU 15 determines that the rotation speed Ne1 of the engine 1 by the starter has increased to a predetermined rotation speed C2 and is in a stable state. That is, it is determined that NV can be sufficiently suppressed, and the process proceeds to step SP9.

  On the other hand, if a negative result is obtained (SP7: N), the engine 1 is started when the rotational speed Ne1 of the engine 1 by the starter does not increase to the predetermined rotational speed C2 due to a decrease in the capacity of the battery or the like. In this case, the ECU 15 proceeds to step SP8 so that the engine 1 can be started.

  That is, the ECU 15 determines whether or not the difference in the rotational speed Ne1 of the engine 1 at the fuel injection timing of the adjacent cylinder or the same cylinder is larger than a predetermined difference value C3 (SP8). The adjacent cylinders refer to two cylinders in which the fuel injection timing comes continuously. For example, when the fuel injection timing comes in the second cylinder after the first cylinder, the two cylinders are adjacent cylinders.

  Specifically, when the rotation speed Ne1 of the engine 1 at the fuel injection timing of the adjacent cylinder is 190 rpm and 200 rpm, respectively, the difference between the rotation speed Ne1 of the adjacent cylinder is 10. When the predetermined difference value C3 is 100, the difference (10) is smaller than the predetermined difference value C3 (100). In this case, the ECU 15 determines that the rotation speed of the engine 1 by the starter is in a stable state with little fluctuation, and proceeds to step SP9.

  Further, the difference in the rotational speed Ne1 of the engine 1 at the fuel injection timing of the same cylinder is the difference in the rotational speed Ne1 of the engine 1 at the timing that comes after the multiple fuel injection timings for one cylinder. Say. Specifically, when the rotational speed Ne1 at the fuel injection timing that has subsequently arrived in the first cylinder is 190 rpm and 200 rpm, as described above, the difference (10) is smaller than the predetermined difference value C3, and the ECU 15 proceeds to step SP9. Transition.

  Then, the ECU 15 performs control so as to start the engine for which NV countermeasures have been completed via steps SP6 to SP8 (SP9), and ends this process.

(3) Effects according to this embodiment As described above, according to this embodiment, when the engine 1 is started, the fuel is produced at the time of the first fuel injection timing after the cylinder discrimination after the cranking by the starter is executed. The fuel is injected at the time of the next fuel injection timing. Furthermore, the fuel is injected while the rotational speed of the engine 1 by the starter is stable. Thereby, the difference of the rotation speed of the engine 1 before and after the first explosion can be reduced, and NV at the start of the engine 1 can be suppressed.

  On the other hand, when the engine 1 is started from an idle stop or when the outside air temperature is low, control is performed so that normal engine start is performed, and fuel is injected at the time of the first fuel injection timing after cylinder discrimination. . Therefore, if the priority is given to starting the engine 1 earlier than suppressing NV at the time of the first explosion, the first explosion can be prevented from being delayed. That is, it is possible to optimize the early start of the engine 1 and the suppression of NV.

  In particular, NV can be more sufficiently suppressed by mounting the ECU 15 according to the present embodiment on a small vehicle having a small space for soundproofing, a low-priced vehicle having poor soundproofing material, or a vehicle having poor rigidity.

1 Engine 11 Crank position sensor 12 Cam position sensor 13 Water temperature sensor 14 Ignition switch 15 ECU
16 Actuator

Claims (6)

In the start control device for controlling the operation at the start of the internal combustion engine,
An interface for inputting a rotation angle of the crank detected by the crank position sensor and a rotation angle of the cam detected by the cam position sensor;
A processor that determines the state of each cylinder based on the rotation angle input by the interface, and determines for each cylinder the timing at which fuel should be injected based on the determined state of each cylinder;
The processor is
Count the number of times it was determined that it was time to inject fuel for each cylinder,
Calculate the number of revolutions of the internal combustion engine for each cylinder at the timing when fuel should be injected,
The calculated number of revolutions for a cylinder whose count value becomes larger than a predetermined value for the first time, and the calculated number of revolutions for an adjacent cylinder that has reached the timing at which fuel should be injected immediately before the cylinder. If the difference is less than a predetermined prescribed difference value, and wherein the controller controls so that the value of the count to inject fuel to start the internal combustion engine into the cylinder was first larger than the predetermined value Starting control device. In the start control device for controlling the operation at the start of the internal combustion engine,
An interface for inputting a rotation angle of the crank detected by the crank position sensor and a rotation angle of the cam detected by the cam position sensor;
A processor that determines the state of each cylinder based on the rotation angle input by the interface, and determines for each cylinder the timing at which fuel should be injected based on the determined state of each cylinder;
The processor is
Count the number of times it was determined that it was time to inject fuel for each cylinder,
Calculate the number of revolutions of the internal combustion engine for each cylinder at the timing when fuel should be injected,
The difference between the calculated rotational speed of the cylinder whose count value becomes larger than a predetermined value for the first time and the calculated rotational speed at the time when the previous fuel injection timing has arrived in the cylinder is obtained. If less than a predetermined prescribed difference value, starting, characterized by controlling so that the value of the count to inject fuel to start the internal combustion engine into the cylinder was first larger than the predetermined value Control device. In the start control device for controlling the operation at the start of the internal combustion engine,
An interface for inputting a rotation angle of the crank detected by the crank position sensor and a rotation angle of the cam detected by the cam position sensor;
A processor that determines the state of each cylinder based on the rotation angle input by the interface, and determines for each cylinder the timing at which fuel should be injected based on the determined state of each cylinder;
The processor is
If the outside air temperature is higher than a predetermined temperature,
Count the number of times it was determined that it was time to inject fuel for each cylinder,
The value of the count by injecting fuel control to start the internal combustion engine with respect to the first time increased since the cylinders than a predetermined value,
If the outside air temperature is lower than a predetermined temperature,
A start control apparatus, characterized in that control is performed so as to start an internal combustion engine by injecting fuel into a cylinder which is first determined to be a timing at which fuel should be injected . In a start control method for controlling an operation at the start of an internal combustion engine,
ECU
A first step of inputting a crank rotation angle detected by the crank position sensor and a cam rotation angle detected by the cam position sensor;
A second step of determining a state of each cylinder based on the rotation angle, and determining, for each cylinder, a timing at which fuel should be injected based on the determined state of each cylinder;
A third step of counting, for each cylinder, the number of times it is determined that it is time to inject fuel;
And a fourth step of controlling so as to start the internal combustion engine value of the count by injecting fuel to the first time increased since the cylinders than a predetermined value,
Furthermore, the ECU
Calculate the number of revolutions of the internal combustion engine for each cylinder at the timing when fuel should be injected,
In the fourth step,
The difference between the rotation speed calculated for the cylinder whose count value has become larger than the predetermined value for the first time and the rotation speed calculated for the adjacent cylinder at which the fuel injection timing comes immediately before the cylinder is determined in advance. If the difference is smaller than the predetermined difference value, control is performed to start the internal combustion engine by injecting fuel into the cylinder whose count value becomes larger than the predetermined value for the first time.
A starting control method. In a start control method for controlling an operation at the start of an internal combustion engine,
ECU
A first step of inputting a crank rotation angle detected by the crank position sensor and a cam rotation angle detected by the cam position sensor;
A second step of determining a state of each cylinder based on the rotation angle, and determining, for each cylinder, a timing at which fuel should be injected based on the determined state of each cylinder;
A third step of counting, for each cylinder, the number of times it is determined that it is time to inject fuel;
And a fourth step of controlling so as to start the internal combustion engine value of the count by injecting fuel to the first time increased since the cylinders than a predetermined value,
Furthermore, the ECU
Calculate the number of revolutions of the internal combustion engine for each cylinder at the timing when fuel should be injected,
In the fourth step,
A predetermined difference between a rotation speed calculated for a cylinder whose count value has become larger than the predetermined value for the first time and a rotation speed calculated at the timing when fuel should be injected in the cylinder last time is predetermined. When the difference value is smaller than the difference value, control is performed so that fuel is injected into the cylinder whose count value becomes larger than the predetermined value for the first time to start the internal combustion engine.
A starting control method. In a start control method for controlling an operation at the start of an internal combustion engine,
ECU
When the outside air temperature is higher than a predetermined temperature,
A first step of inputting a crank rotation angle detected by the crank position sensor and a cam rotation angle detected by the cam position sensor;
A second step of determining a state of each cylinder based on the rotation angle, and determining, for each cylinder, a timing at which fuel should be injected based on the determined state of each cylinder;
A third step of counting, for each cylinder, the number of times it is determined that it is time to inject fuel;
A fourth step for controlling to start the internal combustion engine value of the count by injecting fuel to the first time increased since the cylinders than a predetermined value
With
Furthermore, the ECU
When the outside air temperature is lower than the predetermined temperature,
A start control method comprising a step of controlling to start an internal combustion engine by injecting fuel into a cylinder that is initially determined to be a timing for injecting fuel .

Images