JP2009215961A - Engine start control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent working efficiency from being lowered and a defective starting from occurring due to insufficient scavenging time by securing sufficient cranking time when an engine is started or the engine is started while scavenging during the inspection and maintenance of a vehicle. <P>SOLUTION: When a starter relay has been already turned ON, a second start completion determination rotational speed which is higher than a first start completion determination rotational speed is set (S106), and it is determined whether a throttle is fully opened and an engine hood is opened (S109, S110). When the engine hood is closed and the engine rotational speed is higher than the second start completion determination rotational speed or higher, the starter relay is turned OFF (S112). When the hood is opened and a start signal is turned OFF by operating a start switch, the starter relay is turned OFF (S112). Consequently, the working efficiency of the inspection and maintenance is prevented from being lowered and the defective starting due to insufficient scavenging time is prevented from occurring by securing sufficient cranking time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine start control device for driving a starter to start cranking of an engine and stopping the starter when cranking is finished when it is determined that the start is completed.

  Engines mounted on automobiles are required to have as short a time as possible until completion of starting from the viewpoint of improving fuel efficiency. In particular, in an idling stop vehicle that performs idling stop / automatic restart under a predetermined condition, if the engine cannot be started during the driver's start operation (for example, the foot is switched from the brake to the accelerator), the feeling is impaired. In addition to causing traffic jams, there is a need to shorten the starting time.

  One way to shorten the engine start time is to increase the cranking speed. In order to increase the cranking speed, it is necessary to increase the output of the starter and improve the power supply performance. For example, it is possible to pass a large current through the starter by combining a large capacity battery. Or a method of improving power supply characteristics by providing a capacitor in parallel with the battery.

  When cranking speed is increased by such a method, in order to ensure the durability of the starter, it is controlled so that the power supply to the starter is as short as possible, and the shortest ON time that can be reliably started and It is necessary to control to become. In this case, the starter is generally controlled by determining the start completion based on the engine speed and turning off the starter. The determination speed for determining the start completion is reached only by the drive torque of the starter. The rotational speed is set higher than the possible rotational speed and lower than the idling rotational speed.

  However, combining a high-power starter with a high-performance power source increases the number of revolutions that can be reached only with the starter drive torque, while the idling number of revolutions is often set as low as possible to reduce fuel consumption. . For this reason, in the conventional start control, it may be difficult to determine the completion of the start at a high rotation speed having a sufficient margin with respect to the rotation speed that can be reached only by the starter driving torque.

  Under such circumstances, various inconveniences occur even when the vehicle is inspected and maintained. For example, when measuring the compression of the engine, pull out all spark plugs, fully open the throttle, perform cranking, and measure the compression of each cylinder. Since the rotation speed reaches a higher speed than usual in a short time, the start is completed before the measurement is completed in the case of the determined rotation speed that does not allow sufficient margin for the rotation speed that can be reached only by the starter drive torque as described above. This causes a problem that the starter automatically stops.

  As a technique related to such an engine start, for example, there are techniques disclosed in Patent Document 1 and Patent Document 2. In the technology of Patent Document 1, by prohibiting eco-run control when the engine hood is open with respect to a vehicle that performs eco-run control (idle stop control), electric power is supplied from a vehicle other than the host vehicle at the start of engine operation. The jumper start determination that is started upon supply is performed accurately and reliably to take advantage of battery protection and eco-run control.

Further, in the technique of Patent Document 2, when an engine hood is opened in an engine that suspends operation of some cylinders during idling, the engine is switched to a maintenance-permitted state, and the suspending of some cylinders is canceled. This makes it possible to perform maintenance such as checking for the presence of a misfire cylinder and adjusting the air-fuel ratio.
JP 2001-107768 A JP 2003-176747 A

  In general, when measuring engine compression during vehicle inspection / maintenance, the throttle is fully open because the pumping loss is reduced and the engine speed is increased, and the fuel mixture is cut when the throttle is fully opened. This is to prevent the fuel from being ejected from the plug hole, and the fuel cut at the time of starting all the throttles is a technique that has been generally adopted.

  In addition, the full throttle opening at the time of start-up may be performed in order to perform scavenging, for example, when the plug becomes foggy, during the user's use process. The aim is to perform scavenging in the same procedure as when using a conventional carburetor by cutting the fuel when the throttle is fully started. Depending on how, the cranking rotation speed exceeds the start completion determination rotation speed as in the compression measurement, and the starter automatically stops, and there is a possibility that the startability deteriorates because sufficient scavenging cannot be performed.

  With respect to such a problem, the technique disclosed in Patent Document 1 uniformly prohibits idle stop control while the engine hood is open, which may cause inconvenience during maintenance. Further, the technique disclosed in Patent Document 2 only discloses that the maintenance mode is set when the engine hood is opened, and is specifically difficult to apply to an idle stop vehicle or the like.

  The present invention has been made in view of the above circumstances, and ensures sufficient cranking time when starting the engine at the time of inspection and maintenance of the vehicle and starting the engine while scavenging, reducing workability and reducing the scavenging time. It is an object of the present invention to provide an engine start control device that can prevent a start failure due to a shortage.

  In order to achieve the above object, the first engine start control device according to the present invention drives the starter to start cranking when the engine start condition is satisfied, and when the engine start completion is determined, In the engine start control device that stops the starter and terminates cranking, the start completion determination rotation that is higher than the rotation speed balanced with the driving force of the starter and lower than the idle rotation speed is determined as the determination rotation speed for determining completion of the engine start. When the engine hood is closed with the start completion determination rotation speed setting unit that sets the number, the start completion determination rotation speed is compared with the engine rotation speed to determine the start completion, and the engine hood is opened. And a start completion determination unit that determines start completion based on an operation of the driver when detected.

  The second engine start control device according to the present invention drives the starter to start cranking when the engine start condition is satisfied, and stops the starter when the start of the engine is determined to be complete. In the engine start control device for terminating cranking, a start completion determination rotation speed that is higher than the rotation speed that balances the drive force of the starter and lower than the idle rotation speed is set as the determination rotation speed for determining completion of engine start. When the completion determination rotation speed setting unit and the engine hood are closed, the start completion determination rotation speed is compared with the engine rotation speed to determine the start completion, and when the engine hood is opened, A start completion determination is made by comparing a second start completion determination rotation speed higher than the start completion determination rotation speed with the engine rotation speed. Characterized in that a part.

  According to the present invention, when starting the engine at the time of inspection and maintenance of the vehicle or starting the engine while scavenging, sufficient cranking time can be secured, and start-up failure due to poor workability or lack of scavenging time. Can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 relate to an embodiment of the present invention, FIG. 1 is a configuration diagram of an engine start system, FIG. 2 is a functional block diagram of start control, and FIG. 3 is a flowchart of a start control routine.

  In FIG. 1, reference numeral 1 denotes an engine, and a starter 2 that cranks and starts the engine 1 is connected to the engine 1. In FIG. 1, the starter 2 exemplifies a gear type starter using a DC motor, and includes a magnet switch circuit for connecting / disconnecting the motor to / from the output shaft of the engine 1 by meshing / releasing the gear. A circuit terminal is connected to the battery 4 via the starter relay 3. The battery 4 is, for example, a lead battery, and a capacitor 5 is connected in parallel to improve the characteristics of the lead battery.

  The starter 2 is not limited to a gear type starter, and may be a motor generator that is directly connected to the output shaft of the engine 1 and has both a starter function at the start and a power generation function after the start.

  The starter relay 3 is ON / OFF controlled by an engine control unit (ECU) 50 that electronically controls the engine 1. The ECU 50 includes a peripheral circuit such as an input / output circuit centered on a microcomputer, and is connected to various sensors / switches for detecting the operating state of the engine on the input side, and various actuators for engine control on the output side. Is connected. Further, the ECU 50 is connected to an in-vehicle network (not shown) constituted by a not-shown CAN (Controller Area Network), etc., and communicates with other control devices for controlling automatic transmissions, brakes, suspensions, etc. Exchange.

  Sensors and switches connected to the input side of the ECU 50 include a crank angle sensor 6 that detects a crank angle, a throttle sensor 7 that detects a throttle opening, a start switch 8 that outputs a start signal by manual operation of a driver, There is a hood switch 9 that is turned off when the engine hood is closed and turned on when the engine hood is opened. The actuators connected to the output side of the ECU 50 include the above-described starter relay 3, an injector (not shown), various control valves, and the like.

  The ECU 50 detects the crank angle of the engine 1 from the pulse interval of the pulse signal output from the crank angle sensor 6, calculates the engine speed, and controls the start of the engine 1 using the crank angle and the engine speed as basic parameters. Various controls such as fuel injection control and ignition timing control are performed.

  Normally, the start control of the engine 1 by the ECU 50 is performed by turning on the starter relay 3 to drive the starter 2 when the starter ON operation of the start switch 8 by manual operation or the start condition establishment at the time of idle stop control is determined. When the cranking rotational speed reaches the determination rotational speed (first start completion determination rotational speed) for determining start completion, the starter 2 is automatically stopped.

  The first start completion determination rotation speed is a determination rotation speed for determining start completion by cranking in normal engine start, is higher than the engine rotation speed that can be reached only by the driving force of the starter 2, and is higher than the idle rotation speed. It is set as a low speed. However, in a system with a high-power starter and a high-performance power supply, the engine speed that can be reached only by the driving force of the starter increases, while the idle speed for reducing fuel consumption is set as low as possible. Therefore, if the start completion determination is performed based on the first start completion determination rotation speed, there is a possibility that inconvenience as described below may occur.

  For this reason, the ECU 50 stops the automatic stop of the starter 2 at the normal first start completion determination rotation speed under a specific condition, and determines a determination rotation speed (second start completion determination determination) higher than the first start completion determination rotation speed. The automatic stop of the starter 2 based on a comparison between the engine speed at the time of cranking and the engine speed at the time of cranking and the drive stop of the starter 2 in response to the OFF operation of the start switch 8 are selectively executed.

  That is, when the engine opens and opens the engine hood, the throttle (accelerator) is fully opened and the engine is cranked by operating the start switch 8 for the compression measurement, the first start completion determination rotational speed In some cases, the cranking automatically stops before the completion of the compression measurement after the start completion determination is performed, which causes inconvenience in inspection and maintenance.

  Here, when the compression is measured, the throttle is fully opened to reduce the pumping loss and increase the engine speed, and at the start with the throttle fully open, the fuel is cut to prevent the air-fuel mixture from being ejected from the plug hole. Therefore, even if the engine is cranked by manually operating the start switch 8 in such a state, the cranking rotation speed easily exceeds the normal first start completion determination rotation speed, and the start completion is determined. It is judged and cranking stops automatically, and it interferes with compression measurement.

  Therefore, in the case of starting with the engine hood open and the throttle fully open, the cranking of the engine is controlled by ON / OFF control of the starter relay 3 according to the manual operation of the start switch 8. It is desirable to start / end.

  On the other hand, during operations other than compression measurement, the engine hood may be closed and the throttle may be fully opened to start. In such a case, the starter relay 3 is turned on in response to manual operation of the start switch 8 to crank the engine, and the second start completion determination speed is higher than the normal first start completion determination speed. When the number is exceeded, it is desirable to turn off the starter relay 3 to end the cranking.

  The start under the condition that the engine hood is closed and the throttle is fully open may occur not only during the start of measurement other than the compression measurement at the time of inspection and maintenance of the vehicle, but also in the process of use by the user. For example, when the plug becomes foggy, the user may try to start the engine while scavenging the combustion chamber with the throttle fully open.

  In such a scavenging operation with the throttle fully open, depending on the setting of the first start completion determination rotational speed, the cranking rotational speed exceeds the first start completion determination rotational speed as in the compression measurement, and the starter automatically stops. Therefore, there is a possibility that sufficient scavenging cannot be performed.

  In addition, when the throttle is fully opened, the engine is not normally started due to fuel cut. However, depending on the engine condition, the engine may start with the fuel adhering to the wall of the port. In such a case, the throttle As the engine is open, the engine speed increases to a high speed. Normally, a starter has a built-in one-way clutch for the purpose of protecting the starter when it is turned from the engine side, but this one-way clutch is designed to assume an OFF delay at the normal start. In a state where the rotation is suddenly increased to a high speed, such as when the throttle is fully opened, the one-way clutch may be damaged.

  Therefore, for example, in starting under the condition where the engine hood is closed and the throttle is fully open, the ECU 50 sets the start completion determination rotational speed to be higher than the normal first start completion determination rotational speed. To the second start completion determination rotational speed. This allows normal starting control to be performed by not stepping on the accelerator during inspection and maintenance, making it easier to check the starting system, and ensuring sufficient scavenging even during starting by the user's scavenging operation. Even when the engine is started due to fuel adhering to the wall of the port, the starter can be automatically stopped to avoid damage to the starter.

  The functions related to the start control of the ECU 50 are shown in the block diagram of FIG. As representative functions of the start control, the ECU 50 includes a start determination unit 51 that determines engine start, a first start completion determination rotation number setting unit 52 that sets a first start completion determination rotation number, and a second start completion determination rotation number. The engine is started by the second start completion determination rotation speed setting unit 53 for setting the engine, the cranking end condition determination unit 54 for determining the cranking end condition based on the signals from the throttle sensor 7 and the hood switch 9, and the start determination unit 51. When it is determined, the starter relay 3 is turned on to start cranking, and a start completion determination unit 55 that determines start completion according to the condition determined by the cranking end condition determination unit 54 is provided.

  The start determination unit 51 starts the engine when the start signal from the start operation of the start switch 8 changes from OFF to ON, or when a restart condition based on information input via CAN is satisfied in the idle stop vehicle. The starter relay 3 is turned on to drive the starter 2, and engine cranking is started.

  The first start completion determination rotation speed setting unit 52 sets a rotation speed higher than the engine rotation speed that can be reached only by the driving force of the starter 2 and lower than the idle rotation speed as the first start completion determination rotation speed. The first start completion determination rotational speed is set based on, for example, the engine water temperature in consideration of engine friction.

  The second start completion determination rotation speed setting unit 53 sets the second start completion determination rotation speed as a rotation speed higher than the first start completion determination rotation speed. This second start completion determination rotational speed is based on the assumption that the fuel is cut when the throttle (accelerator) is fully started, and that sufficient scavenging time is secured by cranking and the engine starts due to fuel adhering to the wall of the port. Thus, the number of revolutions that can protect the starter 2 is set based on, for example, the engine water temperature.

  The cranking end condition determination unit 54 determines whether the throttle is fully open based on a signal from the throttle sensor 7 (for example, determines that the throttle is fully open when the signal voltage from the throttle sensor 7 is higher than a preset voltage). When the hood switch 9 is ON, it is determined that the engine hood is open, and the cranking end condition is determined according to the combination of the throttle fully open condition and the engine hood open condition.

  For example, if the throttle is not fully opened at the start of cranking of the engine, a start completion determination is instructed by comparing the engine speed (cranking rotation speed) with the first start completion determination rotation speed, and the throttle is fully open. When only the above is established, a start completion determination is instructed by comparing the engine speed (cranking speed) with the second start completion determination speed. When the throttle fully open condition is satisfied and the engine hood open condition is satisfied, the start completion based on the start signal from the start switch 8 is performed without using any of the first and second start completion determination rotation speeds. Instruct the judgment.

  According to the cranking end condition determined by the cranking end condition determining unit 54, the start completion determining unit 55 has an engine speed (cranking speed) equal to or higher than the first start completion determining speed or the second start completion determining speed. When the start signal is raised, the start is determined to be complete, or when the start signal from the start switch 8 is switched from ON to OFF, the start is determined to be complete. When it is determined that the start has been completed, the starter relay 3 is turned off to stop the starter 2 and finish cranking.

  Specifically, the engine start control by the ECU 50 is realized by a program process executed in the ECU. The flowchart in FIG. 3 is an example of a start control routine executed in the ECU 50. Hereinafter, engine start control will be described with reference to the flowchart in FIG.

  The start control routine is a routine that is executed at regular intervals (for example, 10 msec). First, in the first step S101, it is determined whether start determination is established. As will be described later, this start determination is cleared when cranking is completed, and based on the condition that the start signal from the start switch 8 is switched from OFF to ON, an idle stop vehicle equipped with a manual transmission is used. , Restart from the idle stop state, that is, a predetermined condition based on information input via CAN, for example, the condition that the transmission gear is in the neutral position and the clutch pedal is depressed from the idle stop state is an OR condition To be added.

  If it is determined in step S101 that the start determination is not established, nothing is done and the routine is exited. When the start determination is established, the process proceeds to step S102 to check whether the starter relay 3 has already been turned on. As a result, if the starter relay 3 is not turned on, the process proceeds to step S103, where the starter relay 3 is turned on. In step S104, the cranking time timer for measuring the elapsed time (cranking time) after the start of cranking is cleared. The timer is initialized.

  On the other hand, if the starter relay 3 is already ON in step S102, the first start completion determination rotation speed and the second start completion determination rotation speed are set in steps S105 and S106, respectively. These first and second start completion determination rotation speeds are respectively calculated by referring to a map created by an experiment or simulation in advance with the water temperature as an axis, with interpolation calculation.

  As described above, the first start completion determination rotation speed is a determination rotation speed for determining start completion in a normal operation state under use by the user and automatically stopping the starter 2, and the second start rotation The engine speed is determined when the engine is started while the throttle is fully opened and the combustion chamber is scavenged, such as when the plug becomes fogged under user use, or when the engine hood is used for vehicle inspection and maintenance. When the engine is started for the purpose other than the compression measurement in a state where is opened, it is a determination rotational speed for determining start completion and automatically stopping the starter 2. The second start completion determination rotation speed is stored in the map as data of a rotation speed higher than the first start completion determination rotation speed.

  After the first and second start completion determination rotational speeds are set in steps S105 and S106, the process proceeds to step S107, and it is determined whether or not the cranking time measured by the cranking timer exceeds the set time. If the cranking time exceeds the set time, the process jumps from step S107 to step S112 to turn off the starter relay 3, clears the start determination in step S113, and ends the process. This is a process for protecting the starter by preventing burning of the starter by stopping the cranking within a set time when the engine cannot be started due to some abnormality of the engine.

  If the cranking time is within the set time in step S107, the process proceeds from step S107 to step S108 to increment the cranking time timer. Next, in step S109, whether the throttle is fully opened from the signal of the throttle sensor 7 or not. Determine whether. If the throttle is not fully opened, the process proceeds from step S109 to step S114, and the engine speed at that time is compared with the first start completion determination speed.

  If the engine speed is lower than the first start completion determination speed, the routine exits from step S114 and the starter relay 3 is maintained in the ON state. If the engine speed is higher than the first start completion determination speed, Proceeding from step S114 to step S112, the starter relay 3 is turned off to complete the cranking, and the start determination is cleared in step S113, whereby the substantial processing of this routine is completed and the start is completed.

  On the other hand, if it is determined in step S109 that the throttle is fully open, the process proceeds from step S109 to step S110, and the ON / OFF state of the hood switch 9 is checked to determine whether the engine hood is open. When the engine hood is closed as in the normal state, the process proceeds from step S110 to step S115, and the engine speed is compared with the second start completion determination speed. When the engine speed is less than the second start completion determination speed, the routine exits while the starter relay 3 is kept on, and when the engine speed becomes equal to or higher than the second start completion determination speed, step S112, After the starter relay 3 is turned off in S113 and the start determination is cleared, the start is completed.

  On the other hand, if it is determined in step S110 that the hood is open, the process proceeds from step S110 to step S111, and it is checked whether or not the start signal is ON by operating the start switch 8. If the start signal is ON, the starter relay 3 is continuously turned on to exit the routine. If the start signal is OFF, the starter relay 3 is turned off in step S112, and the start determination clear process in step S113 is performed. Then, this process is terminated.

  With the above processing, when the throttle is not fully open, that is, in the case of normal start, the start completion determination is made based on the first start completion determination rotation speed, and the engine hood is closed but the throttle is fully open The completion of the start is determined based on the second start completion determination rotation speed set to a value higher than the first start completion determination rotation speed. Further, when the throttle is fully open and the engine hood is also open, the operator continues the cranking operation while the start signal is ON by the start operation.

  The above-mentioned start control routine is an example. Depending on the required level at the start of scavenging and inspection / maintenance, it is possible to appropriately combine the method for determining start completion from engine hood open / close information and throttle (accelerator) full open information. is there.

  For example, the second start completion determination rotation speed is set as a high rotation speed value that does not interfere with the compression measurement during inspection and maintenance, and when the engine hood is open, regardless of whether the throttle is fully open or not The cranking may be terminated by the start completion determination based on the second start completion determination rotation speed.

  Further, when the cranking rotation speed by the scavenging operation with the throttle fully opened is sufficiently lower than the first start completion determination rotation speed, the second start as described above is performed even when the engine hood is closed. The cranking may be terminated by turning off the starter relay 3 in conjunction with the turning-off operation of the start switch 8 instead of automatically completing the cranking based on the completion determination rotational speed.

  As a result, even when the engine speed rises in a relatively short time, such as when measuring compression during vehicle inspection and maintenance, it is possible to avoid the end of cranking and making measurement difficult. A sufficient cranking time can be secured to prevent a reduction in work efficiency.

  In addition, when scavenging is started in the process of use by the user, cranking is terminated in the middle of the operation, so that it is possible to prevent a start failure due to insufficient scavenging. Even in the case of a failure, the starter can be automatically turned off to avoid damage to the starter.

  In particular, in a system where the power supply characteristics are improved by paralleling a high-output starter motor or capacitor, etc., and the cranking speed is increased to improve startability, ensuring workability during inspection and maintenance, This is effective for ensuring the scavenging time and safety for the scavenging start.

Configuration diagram of the engine start system, Functional block diagram of start control Start control routine flowchart

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Starter 8 Start switch 9 Hood switch 50 Engine control apparatus 51 Start determination part 52 1st start completion determination rotation speed setting part 53 2nd start completion determination rotation speed setting part 54 Cranking end condition determination part 55 Start completion determination part

Claims (4)

When the engine start condition is satisfied, the starter is driven to start cranking, and when the engine start completion is determined, the starter is stopped and the cranking is ended.
A start completion determination rotation speed setting unit for setting a start completion determination rotation speed that is higher than the rotation speed balanced with the driving force of the starter and lower than the idle rotation speed, as a determination rotation speed for determining the completion of engine start;
When the engine hood is closed, the start completion determination speed is compared with the engine speed to determine the start completion, and when it is detected that the engine hood is opened, the start completion is determined based on the driver's operation. An engine start control device comprising: a start completion determination unit for determining. When the engine start condition is satisfied, the starter is driven to start cranking, and when the engine start completion is determined, the starter is stopped and the cranking is ended.
A start completion determination rotation speed setting unit for setting a start completion determination rotation speed that is higher than the rotation speed balanced with the driving force of the starter and lower than the idle rotation speed, as a determination rotation speed for determining the completion of engine start;
When the engine hood is closed, the start completion determination rotation speed is compared with the engine rotation speed to determine the start completion, and when it is detected that the engine hood is opened, the engine speed is higher than the start completion determination rotation speed. 2. An engine start control device comprising: a start completion determination unit that compares the start completion determination rotation speed of 2 and the engine rotation speed to determine start completion. The start completion determination unit is
When the throttle is fully opened, the completion of the start is determined by comparing the engine speed with a second start completion determination speed higher than the start completion determination speed, regardless of whether the engine hood is open or closed. The engine start control device according to claim 1 or 2, characterized in that The start completion determination unit is
3. The engine start control device according to claim 1, wherein when the throttle is fully opened, the completion of the start is determined based on a driver's operation regardless of whether the engine hood is open or closed.

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