JP2005020795A - Apparatus and method for start control of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for start control of an internal combustion engine which can improve starting characteristics of the internal combustion engine when a capacity of a battery falls at a cryotemperature time or due to a deterioration of the battery. <P>SOLUTION: The apparatus for start control of the internal combustion engine includes a starter 4, and number-of-revolutions detecting means for detecting a number of revolutions of the internal combustion engine or the starter; and controls the starter in response to engine average number-of-revolutions (Ne) detected by the number-of-revolutions detecting means. The apparatus for start control of the internal combustion engine further includes variable means 43 for forming a plurality of circuit configurations having different torque characteristics of the starter 4 with a necessary voltage being constant to drive the starter 4, and circuit configuration switching means 1 for switching the circuit configuration in response to the average number of revolutions (Ne) of the engine; switches to the circuit configuration for generating the highest torque at the engine average number of revolutions (Ne) detected at the internal combustion engine starting time; and cranks in a wide rotating range from the start of the internal combustion engine to a complete explosion. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a start control device and a start control method for an internal combustion engine, and more particularly to a start control device and a start control method for an internal combustion engine that starts the internal combustion engine by switching a starter to a plurality of torque characteristics with a constant voltage. .
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an internal combustion engine such as a gasoline engine or a diesel engine mounted on a vehicle is provided with a starter for starting the internal combustion engine, that is, for maintaining a constant rotational speed. The starter includes a pinion that is movable in the axial direction of a starter that meshes with a gear provided on the internal combustion engine side, a shaft that is supported so as to be movable in the axial direction, and a shaft that is provided with an armature coil on the outer periphery. The field coil is provided on the inner surface of the housing so as to cover the outer periphery of the armature coil. The starter generates a magnetic flux in the field coil by electric power supplied from a battery mounted on the vehicle, and causes a current to flow in the armature coil, rotates the armature coil, and rotates the shaft. When the pinion provided on the shaft meshes with the gear on the internal combustion engine side, the rotation of the starter is transmitted to the internal combustion engine, and the internal combustion engine is rotated to a constant rotational speed.
[0003]
The conventional starter has a constant torque, that is, a torque characteristic generated according to the rotation speed of the starter. Here, at an extremely low temperature, for example, at −25 ° C., the startability of the internal combustion engine deteriorates due to an increase in the viscous resistance of the lubricating oil used in the internal combustion engine. This is because a necessary torque increases when the internal combustion engine is rotated. Therefore, the starter needs to generate a large torque in order to start the internal combustion engine, particularly a large torque when the rotation of the internal combustion engine is in a low rotation range at a very low temperature. Thus, conventionally, an engine starter has been proposed in which the voltage supplied to the starter is increased at low temperatures and the torque generated by the starter is increased when the rotation of the internal combustion engine is in a low rotation range (see Patent Document 1). In this engine starting device, electric power of a starter supplied from a battery is stored in a capacitor in advance, and electric power stored in the capacitor is supplied to the starter at a low temperature.
[0004]
[Patent Document 1]
JP-A-8-93608
[0005]
[Problems to be solved by the invention]
Here, the capacity of the battery varies depending on the outside air temperature. That is, compared with the capacity of the battery at room temperature, for example, 20 ° C., the capacity of the battery at extremely low temperature, for example, −25 ° C. decreases. Therefore, at an extremely low temperature, the power supplied to the starter decreases, and the torque generated by the starter decreases. In the conventional engine starting device, there is a possibility that sufficient electric power stored in the capacitor cannot be secured at an extremely low temperature. Furthermore, the capacity of the battery may be reduced not only at extremely low temperatures but also due to aging of the battery. That is, with the deteriorated battery, there is a possibility that the electric power that needs to be stored in the capacitor at an extremely low temperature cannot be further secured. For these reasons, there is a possibility that the conventional engine starter cannot start the internal combustion engine.
[0006]
As described above, since the torque characteristics of the conventional starter are constant, the torque of the conventional starter becomes zero when the rotation speed reaches a certain value. When the rotational speed required for starting the internal combustion engine, that is, complete explosion, is higher than the rotational speed at which the torque of the starter becomes zero, the starting time becomes longer. In particular, a diesel engine at a very low temperature has a tendency that the starter torque tends to fluctuate even near the rotational speed where the torque of the starter becomes zero, and there is a problem that the starting time becomes longer. As described above, since the capacity of the battery is reduced at extremely low temperatures or deteriorated over time, the starter cannot generate the torque necessary to rotate the internal combustion engine when the start time becomes long. There was a possibility that it could not be started.
[0007]
Therefore, the present invention has been made in view of the above, and it is possible to start an internal combustion engine that can improve the startability of the internal combustion engine when the capacity of the battery is reduced at least at a very low temperature or due to battery deterioration. It is an object to provide a control device and a start control method.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a starter that performs cranking when the internal combustion engine is started, and a rotational speed detection means that detects the rotational speed of the internal combustion engine or the starter, and is detected by the rotational speed detection means. In a start control device for an internal combustion engine controlled by a starter according to the number of revolutions, a plurality of circuit configurations having different voltage characteristics required for driving the starter and different starter torque characteristics, and circuit configurations according to the number of revolutions are provided. Circuit configuration switching means for switching, and the circuit configuration switching means switches to a circuit configuration that generates the highest torque at the rotational speed detected by the rotational speed detection means.
[0009]
According to the present invention, in the low rotation range where the torque required for rotating the internal combustion engine is large, the torque generated by the starter is switched to the circuit configuration of the torque characteristic (torque priority) to rotate the internal combustion engine. In a high rotation range where the required torque is small, the circuit configuration can be switched to a torque characteristic (rotation speed priority) in which the torque generated by the starter is small. Thereby, cranking can be performed in a wide rotation range from when the internal combustion engine is rotated to when the internal combustion engine is started, and even if the torque required to rotate the internal combustion engine at extremely low temperatures increases, The startability of the internal combustion engine can be improved. In addition, since the circuit configuration switching means switches the circuit configuration having a plurality of torque characteristics up to the number of revolutions required to start the internal combustion engine, the startup time of the internal combustion engine, particularly at a very low temperature, can be shortened. it can. As a result, the total electric power required for starting one internal combustion engine can be reduced, and the battery life can be extended or the battery can be downsized (use of a battery with a small capacity).
[0010]
According to the present invention, the start control device for an internal combustion engine further includes temperature detection means for detecting the temperature of the internal combustion engine, and the circuit is provided when the temperature of the internal combustion engine detected by the temperature detection means is higher than a predetermined temperature. The configuration switching means switches to a circuit configuration having a torque characteristic that reduces the generated torque in a low rotation range of the starter.
[0011]
According to the present invention, since the internal combustion engine can be rotated at a low rotation speed even when the starter torque is small except at extremely low temperatures, the torque characteristic (rotation speed priority) circuit reduces the torque generated by the starter. The internal combustion engine is started with the configuration. As a result, when starting the internal combustion engine at times other than extremely low temperatures, in addition to the operational effects of the start control device for the internal combustion engine, it is possible to suppress a decrease in riding comfort when starting the internal combustion engine.
[0012]
In the present invention, the start control device for an internal combustion engine further includes battery voltage detection means for detecting a voltage of a battery that supplies power to the starter, and the battery voltage detected by the battery voltage detection means is greater than a predetermined voltage. Is lower, the circuit configuration switching means switches to a circuit configuration in which the torque generated in the low rotation region of the starter is higher.
[0013]
According to the present invention, even when the power of the battery supplied to the starter is reduced due to extremely low temperatures or due to deterioration of the battery, a circuit having torque characteristics (torque priority) necessary for rotating the internal combustion engine in the low rotation range. The configuration can be switched and the internal combustion engine can be rotated. Thereby, even if the voltage of a battery falls, an internal combustion engine can be rotated and the startability of the internal combustion engine when the capacity | capacitance of a battery falls at the time of extremely low temperature or deterioration of a battery can be improved.
[0014]
According to the present invention, the internal combustion engine start control device further includes a correction means for correcting the temperature of the internal combustion engine detected by the temperature detection means or the voltage of the battery detected by the battery voltage detection means, and the circuit configuration switching The means is characterized in that the circuit configuration is switched based on the temperature of the internal combustion engine or the voltage of the battery corrected by the correction means.
[0015]
According to the present invention, a factor that changes the torque required to rotate the internal combustion engine, such as a heat storage system that operates according to the outside air temperature, a glow plug in a diesel engine, or a lubricating oil of the internal combustion engine whose viscosity resistance changes according to the outside air temperature. The internal combustion engine temperature or battery voltage is corrected in consideration. As a result, the torque generated by the starter can be switched to a circuit mechanism having a torque characteristic that is at least equal to or greater than the minimum torque required to rotate the internal combustion engine, and the total electric power required for starting the internal combustion engine can be further reduced. Thus, the battery life can be extended or the battery can be further downsized.
[0016]
In addition, the present invention includes a starter that performs cranking when the internal combustion engine is started, and a rotational speed detection means that detects the rotational speed of the internal combustion engine or the starter at every predetermined crank angle, and is detected by the rotational speed detection means. In an internal combustion engine start control device that controls a starter according to the number of revolutions, a plurality of circuit configurations in which the voltage required for driving the starter is constant and the torque characteristics of the starter are different, and for each crank angle smaller than a constant crank angle A rotation speed estimation means for estimating the rotation speed, and a circuit configuration switching means for switching the circuit configuration in accordance with the rotation speed estimated by the rotation speed estimation means, the highest rotation speed estimated by the rotation speed detection means. Switching to a circuit configuration that generates high torque is performed by circuit configuration switching means.
[0017]
According to this invention, the rotation speed estimation means estimates a rotation speed that is finer than the rotation speed for each constant crank angle detected by the rotation speed detection means. As a result, it is possible to accurately switch to a circuit configuration that generates the highest torque according to the actual engine speed, and the engine actually rotates at a speed lower than the speed detected by the speed detecting means. Even during this period, it is possible to switch to a circuit configuration that generates the highest torque, and to shorten the engine start time.
[0018]
The present invention further includes a starter that performs cranking at the start of the internal combustion engine, a crank angle detection means, and a rotation speed detection means that detects the rotation speed of the internal combustion engine or the starter at every constant crank angle. In a start control device for an internal combustion engine that controls a starter according to the number of revolutions detected by a detecting means, a plurality of circuit configurations having different voltages required for driving the starter and different torque characteristics of the starter, and number of revolutions detection Circuit configuration switching means for switching the circuit configuration in accordance with the rotation speed detected by the means and the crank angle detected by the crank angle detection means, and the rotation speed and crank angle detection means detected by the rotation speed detection means. Switching to the circuit configuration that generates the highest torque at the detected crank angle by the circuit configuration switching means And it features.
[0019]
According to this invention, the actual engine speed is predicted from the engine speed detected by the engine speed detecting means, and the torque characteristic of the starter is changed. Thereby, after detecting the number of revolutions for each constant crank angle by the number of revolutions detection means, it is possible to follow the timing of changing the torque characteristic as compared with the case where the torque characteristic of the starter is changed. Can be further improved.
[0020]
According to the present invention, in the start control method of the internal combustion engine, a step of determining ON / OFF of a starter that performs cranking when starting the internal combustion engine, and a step of detecting the rotational speed of the internal combustion engine or the starter when the starter is ON And a step of switching the starter at a constant voltage to a torque characteristic that generates the highest torque at the detected number of revolutions, and a step of determining the complete explosion of the internal combustion engine.
[0021]
According to the present invention, in the low rotation range where the torque required for rotating the internal combustion engine is large, the torque generated by the starter is switched to the circuit configuration of the torque characteristic (torque priority) to rotate the internal combustion engine. In a high rotation range where the required torque is small, the circuit configuration can be switched to a torque characteristic (rotation speed priority) in which the torque generated by the starter is small. Thereby, cranking can be performed in a wide rotation range from when the internal combustion engine is rotated to when the internal combustion engine is started, and even if the torque required to rotate the internal combustion engine at extremely low temperatures increases, The startability of the internal combustion engine can be improved.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.
[0023]
FIG. 1 is a diagram showing a schematic configuration example of an internal combustion engine start control device according to the present invention. As shown in FIG. 1, the internal combustion engine start control apparatus according to the present invention includes a circuit configuration switching unit 1 and a starter 4 including a variable unit 43 that forms a plurality of circuit configurations. The circuit configuration switching unit 1 includes a processing unit 11 and a storage unit 12 having various maps 13. Various signals are input to the circuit configuration switching means 1 through an ECU (Engine Control Unit) 2 and an interface unit 3 that control a gasoline engine or a diesel engine (hereinafter simply referred to as an “engine”) that is an internal combustion engine. Is done.
[0024]
Here, the various signals include the average engine speed (Ne), the engine coolant temperature (Thw), the battery voltage (Vb), the crank angle (CA), the ON / OFF (SW1) of the starter switch 6 described later, and the like. . The engine average rotation speed (Ne) is detected by a rotation speed detection means (not shown). This rotational speed detection means includes, for example, a position sensor that provides a detection target on the crankshaft of the engine at a predetermined interval (for example, every 60 degrees), and detects the rotational speed for each constant crank angle of the crankshaft by this detection target. . The crank angle (CA) is detected by a crank angle detecting means (not shown). This crank angle detection means includes, for example, a position sensor that provides detection targets at a plurality of positions (every degree) of the crankshaft and detects the plurality of detection targets. That is, since the number of rotations for each crank angle smaller than the above-mentioned constant crank angle is detected, the current angle of the crankshaft can be detected in detail. The engine coolant temperature (Thw) is detected by temperature detection means (not shown). The temperature detection means includes a temperature sensor that detects the temperature of cooling water circulating at least between the inside of the engine and the radiator. The battery voltage (Vb) is detected by voltage detection means (not shown) provided in the battery 5.
[0025]
Based on the various signals input from the interface unit 3 and the various maps 13 stored in the storage unit 12, the processing unit 11 generates a switching signal SW2 for switching a plurality of circuit configurations of the variable means 43 described later. Output to starter 4. In the figure, various signals are input to the circuit configuration switching means 1 via the ECU 2, but the present invention is not limited to this, and these various signals are directly input to the circuit configuration switching means 1. You may enter. The circuit configuration switching means 1 is provided separately from the ECU 2, but may be configured in the ECU 2 as one of the functions of the ECU 2.
[0026]
As shown in the figure, the starter 4 includes a field coil 41, an armature coil 42, and variable means 43 that forms a plurality of circuit configurations. The field coil 41 is connected to one end of a plurality of branch wires 44 for allowing the current from the battery 5 to flow from the middle, and the other end of the branch wires 44 is connected to the variable means 43. Yes. The armature coil 42 is provided on a shaft (not shown) of the starter 4. The shaft (not shown) supports a pinion that meshes with a gear provided on a flywheel or the like of the crankshaft so that it can move in the axial direction of the shaft. Is transmitted to the crankshaft of the engine. The variable means 43 performs connection / disconnection between the wiring 45b and the branch wiring 44 and connection / disconnection between the branch wirings 44 by the switching signal SW2. Here, the current from the battery 5 is first supplied to the armature coil 42 via the starter switch 6 and the wiring 45a. Next, it is supplied from the armature coil 42 to the field coil 41 via the wiring 45 b and the variable means 43. Then, it is returned from the field coil 41 to the battery 5 via the wiring 45c.
[0027]
FIG. 2 is a diagram for explaining the operation of variable means for forming a plurality of circuit configurations. As shown in FIG. 2A, when the wiring 45b and the branch wiring 44a of the variable means 43 are connected, the power of the battery 5 passes through the starter switch 6, the wiring 45a, the armature coil 42, the wiring 45b, and the branch wiring 44a. The circuit configuration is supplied to the entire field coil 41 (total number of turns). In the case of this circuit configuration, the magnetic flux of the field coil 41 is maximized, and the starter 4 has the maximum torque generated in the low rotation range and the maximum rotation speed as shown in FIG. It becomes. On the other hand, as shown in FIG. 5B, when the wiring 45b is connected to the branch wiring 44b of the variable means 43, the power of the battery 5 is supplied to a part 41a (of the field coil 41 via the wiring 45b and the branch wiring 44b). The number of turns is less than the total number of turns). In the case of this circuit configuration, the magnetic flux of the field coil 41 is reduced, and the starter 4 has a torque characteristic in which the maximum torque generated in the low rotation range is low and the maximum rotation speed is high, as shown in FIG. . Furthermore, as shown in FIG. 5C, when the wiring 45b is connected to the branch wiring 44c of the variable means 43, the power of the battery 5 is further connected to the portion 41b of the field coil 41 via the wiring 45b and the branch wiring 44c. The circuit configuration is supplied to (the smallest number of turns). In the case of this circuit configuration, the magnetic flux of the field coil 41 is minimized, and the starter 4 has a torque characteristic that minimizes the maximum torque generated in the low rotation range and maximizes the maximum rotation speed, as shown in FIG. Become. That is, by connecting / disconnecting the wiring 45b and the branch wiring 44 with the variable means 43, the number of turns of the field coil 41 to which the power from the battery 5 is supplied changes, and the voltage required to drive the starter 4 is reduced. A plurality of circuit configurations having different torque characteristics of the starter 4 can be formed.
[0028]
In the above description, the torque characteristic of the starter 4 is switched by changing the number of turns of the field coil 41. However, depending on the connection of the branch wiring 44, a plurality of torque characteristics can be obtained. In FIG. 3, the number of turns of the field coil 41 to which power from the battery 5 is supplied is the same, and the position with respect to the armature coil 42 is changed. In FIG. 6A, a circuit configuration for connecting the wiring 45b and the branch wiring 44d of the variable means 43 is shown. In FIG. 5B, a circuit for connecting the wiring 45b to the branch wiring 44b of the variable means 43 and the branch wirings 44e and 44f. In the configuration, FIG. 2C shows a circuit configuration in which the wiring 45b is connected to the branch wiring 44a of the variable means 43 and the branch wirings 44f and 44g. In any of the circuit configurations, the power from the battery 5 is supplied to a part 41c (the same number of turns) of the field coil 41, but the distance from the armature coil 42 is different. As shown in FIG. 4D, in the case of a circuit configuration in which the distance between a portion 41c of the field coil 41 to which power from the battery 5 is supplied and the armature coil 42 is the shortest (FIG. 5A), The starter 4 has a torque characteristic that increases the maximum torque generated in the low rotation range. On the other hand, in the case of a circuit configuration in which the distance between the part 41c of the field coil 41 supplied with power from the battery 5 and the armature coil is the longest ((c) in the figure), the starter 4 has a maximum rotational speed. Torque characteristics. In the case of a circuit configuration in which the distance between the part 41c of the field coil 41 and the armature coil 42 is intermediate (FIG. 5B), the starter 4 has intermediate torque characteristics.
[0029]
Next, an internal combustion engine start control method using the internal combustion engine start control device will be described.
[0030]
[First embodiment]
First, starting control of the internal combustion engine based on the engine average rotational speed (Ne) detected by the rotational speed detection means and the engine coolant temperature (Thw) detected by the temperature detection means. A method will be described. FIG. 4 is an operation flow of the start control device for the internal combustion engine according to the first embodiment. FIG. 5 is a graph showing the relationship among the engine average speed (Ne), the engine coolant temperature (Thw), and the torque characteristics of the starter. First, as shown in FIG. 4, the ignition (I / G) is turned on, and the vehicle on which the engine is mounted is turned on (step ST101). Next, the processing unit 11 of the circuit configuration switching unit 1 reads the engine coolant temperature (Thw) input to the ECU 2 via the interface unit 3 (step ST102). The engine coolant temperature (Thw) read by the processing unit 11 is appropriately stored in the storage unit 12.
[0031]
Next, the processing unit 11 reads a map 13 that is a relationship between the engine coolant temperature (Thw) and the engine average rotational speed (Ne) shown in FIG. 5A from the storage unit 12, and the engine coolant temperature (Thw) is It is determined whether or not the temperature is lower than a predetermined water temperature (Thw1) on the map 13 (step ST103). Here, the predetermined water temperature (Thw1) in the map 13 is set to a temperature at which the engine can be started without changing the torque characteristics of the starter 4 (for example, at a normal temperature of about 20 ° C.). When the engine cooling water temperature (Thw) is lower than the predetermined water temperature (Thw1), for example, when the outside air temperature is extremely low, the variable torque control execution flag is turned ON (step ST104). Next, initial torque characteristics (Ne = 0) are set (step ST105). That is, based on the engine coolant temperature (Thw), the processing unit 11 determines the torque characteristic (A1 or B1) when the engine average rotational speed (Ne) is Ne = 0 from the map 13 shown in FIG. To do. Then, the processing unit 11 outputs a switching signal SW2 that causes the variable unit 43 to switch to a circuit configuration corresponding to the torque characteristic (A1 or B1). The variable unit 43 performs wiring 45b based on the switching signal SW2. Are connected / disconnected to / from the branch wiring 44 or connected / disconnected between the branch wirings 44.
[0032]
Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 input to the ECU 2 via the interface unit 3, and determines whether or not the starter 4 is ON (step ST106). If the starter 4 is ON, the processing unit 11 reads the average engine speed (Ne) input to the ECU 2 via the interface unit 3 (step ST107). On the other hand, if starter 4 is OFF, it will return to step ST102 and will repeat the operation | movement to this step ST102-106. Next, torque characteristics corresponding to the average engine speed (Ne) are set (step ST108). That is, the processing unit 11 determines, based on the engine coolant temperature (Thw) and the average engine speed (Ne), the torque characteristics (A1, B1, C1) of the starter 4 from the map 13 shown in FIG. One). Then, the processing unit 11 outputs a switching signal SW2 to the variable means 43, and the variable means 43 switches the circuit configuration based on the switching signal SW2. Here, when the engine cooling water temperature (Thw) is lower than the predetermined water temperature (Thw1), the torque characteristic of the starter 4 decreases as the average engine speed (Ne) increases, as shown in FIG. The map 13 is formed so that the maximum torque in the rotation region decreases, that is, from the characteristics A1 to C1.
[0033]
Then, the processing unit 11 determines whether or not the complete explosion determination flag of the engine of the ECU 2 is turned on via the interface unit 3 (step ST109). If the complete explosion determination flag for the engine is not ON, the process returns to step ST106, and the operations from step ST106 to step ST109 are repeated. That is, the average engine speed (Ne) is read again, the torque characteristics of the starter 4 are determined from the map 13 shown in FIG. 5B, and the circuit configuration of the torque characteristics determined by the variable means 43 is switched. On the other hand, when the complete explosion determination flag of the engine is ON, the engine has started, and the start control of the internal combustion engine is terminated.
[0034]
As described above, in the low rotation range where the torque required to rotate the engine is large, the circuit configuration is switched to the torque characteristic A1 or B1 in which the torque generated by the starter 4 increases. On the other hand, in the high rotation range where the torque required for rotating the engine is small, it is possible to switch to the circuit configuration of the torque characteristic C1 where the torque generated by the starter 4 becomes small. As a result, cranking can be performed in a wide rotation range from when the engine is rotated to when the engine is started, and the engine is rotated at an extremely low temperature (the engine cooling water temperature (Thw) is equal to or lower than the predetermined water temperature (Thw1)). Even if the torque required for the increase is increased, the engine startability can be improved. Further, since the variable means 43 changes the torque characteristic of the starter 4 by changing the circuit configuration by the switching signal SW2 of the circuit configuration switching means 1 up to the number of revolutions necessary for starting the engine, the engine start time, in particular, The starting time at extremely low temperatures can be shortened. Thereby, the total electric power required for starting the internal combustion engine once can be reduced, and the life of the battery 5 can be extended or the battery 5 can be downsized (use of a battery having a small capacity).
[0035]
When the engine coolant temperature (Thw) is higher than the predetermined coolant temperature (Thw1) in step ST103, the torque characteristic (C1 or D1) corresponding to the engine coolant temperature (Thw) is set (step ST110). That is, the processing unit 11 determines the torque characteristic (C1 or D1) at which the maximum rotation speed of the starter 4 is increased from the map 13 shown in FIG. . Then, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST111). If the starter 4 is ON, the engine of the ECU 2 is completed. It is determined whether or not the explosion determination flag is turned on (step ST112). If the engine complete explosion determination flag is not ON, the process returns to step ST111, and the operations up to steps ST111 and ST112 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0036]
As described above, since the engine can be rotated in a low rotation range even when the torque of the starter 4 is small except when the temperature is extremely low (the engine cooling water temperature (Thw) is equal to or higher than the predetermined water temperature (Thw1)), the starter 4 The engine is started with a circuit configuration of torque characteristics (C1 or D1) where the generated torque is reduced. Thereby, when starting an engine except at the time of very low temperature, the fall of the riding comfort at the time of engine starting can be suppressed.
[0037]
[Modification 1]
FIG. 6 is a diagram illustrating an operation flow of the start control device for the internal combustion engine according to the modification of the first embodiment. The difference between the operation flow shown in FIG. 4 and the operation flow shown in FIG. 4 is that the predicted water temperature (Thw2) is calculated from the engine cooling water temperature (Thw) and the water temperature in the heat storage tank (Thth), and this predicted water temperature (Thw2) is calculated. It is a point replaced with engine cooling water temperature (Thw). Some vehicles have a heat storage system that supplies hot water stored in the heat storage tank in advance to the engine cooling water when the engine is started, that is, heat storage preheating, in order to prevent engine cooling water from freezing at extremely low temperatures. There is.
[0038]
Here, if this heat storage preheating is performed at the time of starting, the engine cooling water temperature (Thw) may change suddenly, and the engine starting control may not be performed accurately. That is, the engine coolant temperature (Thw) read by the processing unit 11 and the actual engine coolant temperature are significantly different, and the position of the engine coolant temperature (Thw) in the map 13 shown in FIG. The timing at which the torque characteristic 4 is changed may be significantly different from the timing based on the actual engine coolant temperature. Therefore, it is necessary to have correction means for correcting the engine coolant temperature (Thw) read by the processing unit 11 based on the water temperature (Thth) in the heat storage tank. Hereinafter, an operation flow when this correction unit is used will be described. The torque characteristics of the map 13 and the starter 4 stored in the storage unit 12 of the circuit configuration switching unit 1 are the same as those in the first embodiment.
[0039]
First, as shown in FIG. 6, the ignition (I / G) is turned on, the vehicle on which the engine is mounted is turned on (step ST101), and the processing unit 11 of the circuit configuration switching means 1 (Thw) and the heat storage tank water temperature (Thth) are read (step ST121). Next, the processing unit 11 determines whether or not a heat storage system (not shown) is performing heat storage preheating (step ST122). When the heat storage preheat is being executed, a predicted water temperature (Thw2) that is an actual engine cooling water temperature is calculated from the read engine cooling water temperature (Thw) and the heat storage tank water temperature (Thth) (step ST123). Next, the processing unit 11 replaces the calculated predicted water temperature (Thw2) with the engine cooling water temperature (Thw) (step ST124). Next, the processing unit 11 reads the map 13 which is a relationship between the engine coolant temperature (Thw) and the engine average rotation speed (Ne) shown in FIG. 5A from the storage unit 12 and replaces the replaced engine coolant temperature ( It is determined whether or not (Thw) is lower than a predetermined water temperature (Thw1) on the map 13 (step ST103). If the heat storage preheat is not executed, it is determined whether or not the read engine cooling water temperature (Thw) is lower than a predetermined water temperature (Thw1) (step ST103). When the engine cooling water temperature (Thw) is higher than the predetermined water temperature (Thw1), the torque characteristic corresponding to the engine cooling water temperature (Thw) is set (step ST110), and it is determined whether the starter 4 is ON (step) If the starter 4 is ON, it is determined whether the complete explosion determination flag for the engine of the ECU 2 is ON (step ST112). If the engine complete explosion determination flag is not ON, the process returns to step ST111, and the operations up to steps ST111 and ST112 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0040]
On the other hand, when the engine cooling water temperature (Thw) is lower than the predetermined water temperature (Thw1), the variable torque control execution flag is turned on (step ST104), and the initial torque characteristic (Ne = 0) is set (step ST105). Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST106). If the starter 4 is ON, the processing unit 11 reads the average engine speed (Ne) (step ST107). If the starter 4 is OFF, the processing unit 11 returns to step ST121 and repeats the operations from step ST121 to step ST106. . Next, the torque characteristic is set according to the average engine speed (Ne) (step ST108), and it is determined whether or not the complete explosion determination flag of the engine is turned on (step ST109). If the engine complete explosion determination flag is not ON, the process returns to step ST106, and the operations of steps ST106 to ST109 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0041]
As described above, when the torque required to rotate the engine is changed by the heat storage system that operates according to the outside air temperature, the engine cooling water temperature (Thw) is corrected, and the variable means is changed by the switching signal SW2 of the circuit configuration switching means 1. No. 43 is switched to a circuit configuration having a torque characteristic such that the torque generated by the starter 4 is at least equal to or greater than the minimum torque required to rotate the engine. As a result, the startability of the engine can be improved, and the total power required for starting the engine once can be further reduced, so that the battery life can be extended or the battery can be further downsized. .
[0042]
[Modification 2]
FIG. 7 is a diagram illustrating an operation flow of the start control device for the internal combustion engine according to the modification of the first embodiment. The difference between the operation flow shown in FIG. 4 and the operation flow shown in FIG. 4 is that the correction coefficient (K1) is calculated from the battery voltage (Vb) and the glow preheat elapsed time (Tgp), and the engine cooling water temperature (Thw) The predicted water temperature (Thw3) is calculated from the correction coefficient (K1), and the predicted water temperature (Thw3) is replaced with the engine cooling water temperature (Thw). Some diesel engines mounted on vehicles have a glow plug and perform preheating inside the diesel engine at an extremely low temperature, that is, glow preheating.
[0043]
Here, normally, the diesel engine is started after glow preheating for a predetermined time (for example, 10 seconds) is performed, but depending on the driver, the diesel engine may be started before the predetermined time elapses. In this case, preheating inside the diesel engine is insufficient, and the startability of the engine may be deteriorated. That is, since the torque generated by the diesel engine due to combustion decreases, the torque characteristic of the starter 4 is changed by the map 13 shown in FIG. 5A based on the engine coolant temperature (Thw) read by the processing unit 11. However, the diesel engine may not start. Therefore, the processing unit 11 needs to have correction means for correcting the engine cooling water temperature (Thw) read based on the correction coefficient (K1) calculated from the battery voltage (Vb) and the glow preheat elapsed time (Tgp). is there. Hereinafter, an operation flow when this correction unit is used will be described. The torque characteristics of the map 13 and the starter 4 stored in the storage unit 12 of the circuit configuration switching unit 1 are the same as those in the first embodiment.
[0044]
First, as shown in FIG. 7, the ignition (I / G) is turned on, the vehicle on which the engine is mounted is turned on (step ST101), and the processing unit 11 of the circuit configuration switching means 1 (Thw) is read (step ST102). Next, the processing unit 11 determines whether or not a glow plug (not shown) is performing glow preheating (step ST131). When the glow preheat is being executed, the battery voltage (Vb) and the glow preheat elapsed time (Tgp) are read (step ST132). Next, the processing unit 11 determines whether or not the starter 4 is ON (step ST133). If the starter 4 is ON, the processing unit 11 uses the read battery voltage (Vb) and the glow preheat elapsed time (Tgp). A correction coefficient (K1) is calculated (step ST134). On the other hand, if the starter 4 is OFF, the processing unit 11 returns to step ST132 and repeats reading of the battery voltage (Vb) and the glow preheat elapsed time (Tgp). Next, the processing unit 11 calculates a predicted water temperature (Thw3) from the read engine cooling water temperature (Thw) and the calculated correction coefficient (K1) (step ST135). That is, when the preheating inside the diesel engine is insufficient, the temperature decrease due to the difference between the predetermined time and the glow preheat time is replaced with the temperature decrease of the engine cooling water for correction. Next, the processing unit 11 replaces the calculated predicted water temperature (Thw3) with the engine cooling water temperature (Thw) (step ST136).
[0045]
Next, the processing unit 11 reads the map 13 which is a relationship between the engine coolant temperature (Thw) and the engine average rotation speed (Ne) shown in FIG. 5A from the storage unit 12 and replaces the replaced engine coolant temperature ( It is determined whether or not (Thw) is lower than a predetermined water temperature (Thw1) on the map 13 (step ST103). When glow preheat is not executed, it is determined whether or not the read engine cooling water temperature (Thw) is lower than a predetermined water temperature (Thw1) (step ST103). When the engine cooling water temperature (Thw) is higher than the predetermined water temperature (Thw1), the torque characteristic corresponding to the engine cooling water temperature (Thw) is set (step ST110), and it is determined whether the starter 4 is ON (step) If the starter 4 is ON, it is determined whether the complete explosion determination flag for the engine of the ECU 2 is ON (step ST112). If the engine complete explosion determination flag is not ON, the process returns to step ST111, and the operations up to steps ST111 and ST112 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0046]
On the other hand, when the engine cooling water temperature (Thw) is lower than the predetermined water temperature (Thw1), the variable torque control execution flag is turned on (step ST104), and the initial torque characteristic (Ne = 0) is set (step ST105). Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST106). If the starter 4 is ON, the processing unit 11 reads the average engine speed (Ne) (step ST107). If the starter 4 is OFF, the processing unit 11 returns to step ST102 and repeats the operations from step ST102 to step ST106. . Next, the torque characteristic is set according to the average engine speed (Ne) (step ST108), and it is determined whether or not the complete explosion determination flag of the engine is turned on (step ST109). If the engine complete explosion determination flag is not ON, the process returns to step ST106, and the operations of steps ST106 to ST109 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0047]
As described above, when the torque required to rotate the engine is changed by the glow plug that operates according to the outside air temperature, the engine cooling water temperature (Thw) is based on the battery voltage (Vb) and the glow preheat elapsed time (Tgp). The variable means 43 is corrected by the correction coefficient (K1), and the variable means 43 uses the switching signal SW2 of the circuit configuration switching means 1 so that the torque generated by the starter 4 is at least equal to or higher than the torque necessary for rotating the engine. Switch to the circuit configuration. As a result, the startability of the engine can be improved, and the total power required for starting the engine once can be further reduced, so that the battery life can be extended or the battery can be further downsized. .
[0048]
[Modification 3]
FIG. 8 is a diagram illustrating an operation flow of the start control device for the internal combustion engine according to the modification of the first embodiment. The difference between the operation flow shown in FIG. 4 and the operation flow shown in FIG. 4 is that the correction coefficient (K2) is calculated from the engine coolant temperature (Thw) and the lubricating oil viscosity (W1), and the engine coolant temperature (Thw) The predicted water temperature (Thw4) is calculated from the correction coefficient (K2), and the predicted water temperature (Thw4) is replaced with the engine cooling water temperature (Thw). The engine mounted on the vehicle is injected with lubricating oil, and the sliding resistance is reduced and protected by this lubricating oil.
[0049]
Here, as a lubricating oil for an engine, a lubricating oil having a viscosity determined at the time of shipment of the vehicle is usually injected. However, the driver may inject a lubricating oil having a viscosity different from that of the lubricating oil at the time of shipment. In this case, the friction of the engine is greatly different from that at the time of shipment, and the engine start control may not be performed accurately. Therefore, it is necessary to have correction means for correcting the engine coolant temperature (Thw) read by the processing unit 11 based on the correction coefficient (K2) calculated from the lubricating oil viscosity (W1). Hereinafter, an operation flow when this correction unit is used will be described. The torque characteristics of the map 13 and the starter 4 stored in the storage unit 12 of the circuit configuration switching unit 1 are the same as those in the first embodiment.
[0050]
First, as shown in FIG. 8, the ignition (I / G) is turned on, the vehicle in which the engine is mounted is turned on (step ST101), and the processing unit 11 of the circuit configuration switching means 1 (Thw) and lubricating oil viscosity (W1) are read (step ST141). Next, the processing unit 11 calculates a correction coefficient (K2) from the read engine cooling water temperature (Thw) and the lubricating oil viscosity (W1) (step ST142). Here, the reason why the correction coefficient (K2) is calculated from the engine coolant temperature (Thw) and the lubricant viscosity (W1) is that the viscosity resistance of the lubricant viscosity (W1) varies depending on the engine temperature. Next, the processing unit 11 calculates a predicted water temperature (Thw4) from the read engine cooling water temperature (Thw) and the calculated correction coefficient (K2) (step ST143). That is, the change in the viscosity resistance of the lubricating oil, which changes depending on the outside air temperature, is replaced with the change in the temperature of the engine cooling water for correction. Next, the processing unit 11 replaces the calculated predicted water temperature (Thw4) with the engine cooling water temperature (Thw) (step ST144).
[0051]
Next, the processing unit 11 reads the map 13 which is a relationship between the engine coolant temperature (Thw) and the engine average rotation speed (Ne) shown in FIG. 5A from the storage unit 12 and replaces the replaced engine coolant temperature ( It is determined whether or not (Thw) is lower than a predetermined water temperature (Thw1) on the map 13 (step ST103). When the engine cooling water temperature (Thw) is higher than the predetermined water temperature (Thw1), the torque characteristic corresponding to the engine cooling water temperature (Thw) is set (step ST110), and it is determined whether the starter 4 is ON (step) If the starter 4 is ON, it is determined whether the complete explosion determination flag for the engine of the ECU 2 is ON (step ST112). If the engine complete explosion determination flag is not ON, the process returns to step ST111, and the operations up to steps ST111 and ST112 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0052]
On the other hand, when the engine cooling water temperature (Thw) is lower than the predetermined water temperature (Thw1), the variable torque control execution flag is turned on (step ST104), and the initial torque characteristic (Ne = 0) is set (step ST105). Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST106). If the starter 4 is ON, the processing unit 11 reads the average engine speed (Ne) (step ST107). If the starter 4 is OFF, the processing unit 11 returns to step ST141 and repeats the operations of steps ST141 to ST106. . Next, the torque characteristic is set according to the average engine speed (Ne) (step ST108), and it is determined whether or not the complete explosion determination flag of the engine is turned on (step ST109). If the engine complete explosion determination flag is not ON, the process returns to step ST106, and the operations of steps ST106 to ST109 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control.
[0053]
As described above, if the torque required to rotate the engine changes due to the change in the viscous resistance of the lubricating oil injected into the engine due to the outside air temperature, the engine cooling water temperature (Thw) is changed to the engine cooling temperature. The variable means 43 is corrected by a correction signal (K2) based on the water temperature (Thw) and the lubricating oil viscosity (W1), and the torque generated by the starter 4 causes at least the engine to rotate by the switching signal SW2 of the circuit configuration switching means 1. Therefore, the circuit configuration is changed to a torque characteristic that is more than the minimum required torque. As a result, the startability of the engine can be improved, and the total power required for starting the engine once can be further reduced, so that the battery life can be extended or the battery can be further downsized. .
[0054]
[Second Embodiment]
Next, starting control of the internal combustion engine based on the average engine speed (Ne) which is the rotational speed detected by the rotational speed detection means and the battery voltage (Vb) which is the battery voltage detected by the battery voltage detection means. A method will be described. FIG. 9 is an operation flow of the start control device for the internal combustion engine according to the second embodiment. FIG. 10 is a diagram showing the relationship among the engine average speed (Ne), the battery voltage (Vb), and the torque characteristics of the starter. First, as shown in FIG. 9, the ignition (I / G) is turned on, and the vehicle on which the engine is mounted is turned on (step ST201). Next, the processing unit 11 of the circuit configuration switching unit 1 reads the battery voltage (Vb) input to the ECU 2 via the interface unit 3 (step ST202). The battery voltage (Vb) read by the processing unit 11 is appropriately stored in the storage unit 12.
[0055]
Next, the processing unit 11 reads a map 13 that is a relationship between the battery voltage (Vb) and the engine average speed (Ne) shown in FIG. 10A from the storage unit 12, and the battery voltage (Vb) is the map 13. It is determined whether it is lower than the predetermined voltage (Vb1) (step ST203). Here, the predetermined voltage (Vb1) in the map 13 is set to a voltage at which the engine can be started without changing the torque characteristics of the starter 4. When the battery voltage (Vb) is lower than the predetermined voltage (Vb1), for example, when the outside temperature is extremely low or when the battery 5 is deteriorated due to aging deterioration and the capacity of the battery 5 is reduced, the variable torque control is executed. The flag is turned on (step ST204). Next, an initial torque characteristic (Ne = 0) is set (step ST205). That is, based on the battery voltage (Vb), the processing unit 11 determines the torque characteristic (A2) when the engine average speed (Ne) is Ne = 0 from the map 13 shown in FIG. Then, the processing unit 11 outputs a switching signal SW2 that causes the variable unit 43 to switch to a circuit configuration corresponding to the torque characteristic (A2). The variable unit 43 branches from the wiring 45b based on the switching signal SW2. Connection / disconnection with the wiring 44 or connection / disconnection between the branch wirings 44 is performed.
[0056]
Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST206). If the starter 4 is ON, the processing unit 11 reads the average engine speed (Ne) (step ST207). On the other hand, if starter 4 is OFF, it will return to step ST202 and will repeat the operation | movement to this step ST202-206. Next, torque characteristics corresponding to the average engine speed (Ne) are set (step ST208). That is, the processing unit 11 determines the torque characteristic (A2 or B2) of the starter 4 from the map 13 shown in FIG. 10A based on the battery voltage (Vb) and the engine average speed (Ne). Then, the processing unit 11 outputs a switching signal SW2 to the variable means 43, and the variable means 43 switches the circuit configuration based on the switching signal SW2. Here, when the battery voltage (Vb) is lower than the predetermined voltage (Vb1), the torque characteristic of the starter 4 decreases as the engine average speed (Ne) increases, as shown in FIG. The map 13 is formed so that the maximum torque in the region decreases, that is, from the characteristics A2 to B2.
[0057]
Then, processing unit 11 determines whether or not the complete explosion determination flag of the engine has been turned ON (step ST209). If the complete explosion determination flag of the engine is not ON, the process returns to step ST206, and the operations from step ST206 to step 209 are repeated. That is, the average engine speed (Ne) is read again, the torque characteristics of the starter 4 are determined from the map 13 shown in FIG. 5B, and the circuit configuration of the torque characteristics determined by the variable means 43 is switched. On the other hand, when the complete explosion determination flag of the engine is ON, the engine has started, and the start control of the internal combustion engine is terminated.
[0058]
As described above, when the power of the battery 5 supplied to the starter 4 decreases due to extremely low temperature or due to deterioration of the battery 5, the torque characteristic of the starter 4 becomes a curve like E in FIG. The engine can be rotated by switching to the circuit configuration of the torque characteristic A2 that generates the torque necessary to rotate the engine in the low rotation range. Further, as shown in FIG. 5C, when the engine is started by the torque characteristic E of the starter 4 when the capacity of the battery 5 is reduced, the relationship between the start time and the battery voltage (Vb) is indicated by an arrow F It becomes the curve. On the other hand, when the torque characteristic of the starter 4 is changed when the capacity of the battery 5 is reduced and the engine is started, the relationship between the start time and the battery voltage (Vb) is a curve indicated by an arrow G. When the curves F and G are compared, in the battery 5 having a reduced capacity, the time during which the engine can be started is longer in the curve G that changes the torque characteristics of the starter 4. From these, even if the voltage of the battery 5 decreases, the engine can be rotated, and the startability of the engine when the capacity of the battery 5 decreases due to extremely low temperature or due to the deterioration of the battery 5 can be improved. .
[0059]
In step ST203, when the battery voltage (Vb) is higher than the predetermined voltage (Vb1), that is, when the battery 5 is close to a new state, the torque characteristic (C2) corresponding to the battery voltage (Vb) is set. (Step ST210). That is, the processing unit 11 determines the torque characteristic (C2) at which the maximum rotational speed of the starter 4 is increased from the map 13 shown in FIG. ON / OFF (SW1) of the switch 6 is read to determine whether or not the starter 4 is ON (step ST211). If starter 4 is ON, processing unit 11 determines whether or not the complete explosion determination flag for the engine of ECU 2 has been turned ON (step ST212). If the engine complete explosion determination flag is not ON, the process returns to step ST211, and the operations up to steps ST211 and 212 are repeated. If the engine complete explosion determination flag is ON, the engine has started and the internal combustion engine is started. End control. Thereby, when starting an engine except at the time of very low temperature, the fall of the riding comfort at the time of engine starting can be suppressed.
[0060]
In the first and second embodiments, the rotational speed detection means detects the engine average rotational speed (Ne) for each constant crank angle. For example, in the case where the detection target detected by the rotation speed detection means is provided on the crankshaft at predetermined intervals of 60 degrees, the engine average rotation speed is determined by the ECU 2 based on the time until the crankshaft rotates at a crank angle of 60 °. (Ne) is calculated. Here, a normal engine is in one cycle, and its operation includes a compression stroke and an expansion stroke. In the compression stroke, the rotational speed when the piston rises is minimum, and in the expansion stroke, the rotational speed when the piston descends is maximum. Therefore, if the interval at which the detection target is provided on the crankshaft is wide, that is, if the constant crank angle is large, even if the torque characteristic of the starter 4 is changed by the average engine speed (Ne), There are cases where it is not possible to switch to a circuit configuration having the highest torque characteristics based on the rotational speed.
[0061]
Therefore, in the first and second embodiments, the interval at which the detection target is provided on the crankshaft may be narrowed (for example, every time). That is, the average engine speed (Ne) detected by the rotational speed detection means may be set to a fine rotational speed by narrowing the interval at which the detection target is provided on the crankshaft, that is, reducing the constant crank angle. Thereby, it is possible to accurately switch to a circuit configuration that generates the highest torque according to the actual engine speed, and in actuality even during a period in which the engine is rotating at a speed slower than the average speed, It is possible to switch to a circuit configuration that generates the highest torque, and to shorten the engine start time.
[0062]
[Third embodiment]
Next, an internal combustion engine start control method based on the rotational speed estimated by the rotational speed estimation means will be described. FIG. 11 is a diagram illustrating an operation flow of the start control device for the internal combustion engine according to the third embodiment. FIG. 12 is a diagram showing the relationship between the starter current value (Ist) and the torque characteristics of the starter. In this internal combustion engine start control method, the actual engine speed is replaced with a starter current value (Ist). The starter current value (Ist) varies in detail depending on the engine speed and crank angle. The starter current value (Ist) decreases as the actual engine speed decreases, and increases as the engine speed increases. That is, the engine speed can be estimated for each crank angle that is smaller than the engine average speed (Ne) for each constant crank angle detected by the speed detection means from the starter current value (Ist). An operation flow when the actual engine speed is replaced with the starter current value (Ist) will be described. In FIG. 1, the starter current value detection means is not shown as an example of the rotation speed estimation means for detecting the starter current value (Ist), but either the field coil 41 or the armature coil 42 constituting the starter 4 is not shown. A starter current value (Ist) can be detected by providing an ammeter.
[0063]
First, as shown in FIG. 11, when the ignition (I / G) is turned on (step ST301) and the engine startability deteriorates at a very low temperature or the like, the processing unit 11 of the circuit configuration switching means 1 The control execution flag is turned on (step ST302). Next, an initial torque characteristic is set based on the rotational speed detection means (step ST303), it is determined whether the starter 4 is ON (step ST304). If the starter 4 is ON, the starter current value is determined. (Ist) is read (step ST305), and if the starter 4 is OFF, the process returns to step ST302, and the operations of steps ST302 to 304 are repeated. Next, the processing unit 11 sets torque characteristics corresponding to the read starter current value (Ist) (step ST306). That is, based on the starter current value (Ist), the processing unit 11 calculates the torque characteristic (any one of A3, B3, and C3) of the starter 4 from the threshold value (Ist1, Ist2) of the map 13 shown in FIG. decide. Then, the processing unit 11 outputs a switching signal SW2 to the variable means 43, and the variable means 43 switches the circuit configuration based on the switching signal SW2.
[0064]
For example, as shown in FIG. 4A, when the starter current value (Ist) is higher than the threshold value Ist1, the circuit configuration is switched to the torque characteristic A3 that maximizes the maximum torque generated by the starter 4 in the low rotation range ( (See (b) in the figure). In addition, when the starter current value (Ist) is lower than the threshold value Ist1 and the starter current value (Ist) is higher than the threshold value Ist2, the torque characteristic that the maximum torque generated by the starter 4 is low and the maximum rotation speed is high in the low rotation range. Switch to the circuit configuration of B3. Further, when the starter current value (Ist) is higher than the threshold value Ist2, the circuit configuration is switched to the torque characteristic C3 in which the maximum torque generated by the starter 4 is minimum and the maximum rotation speed is high in the low rotation range. As a result, the starter current value (Ist) between the threshold value Ist1 and the threshold value Ist2 increases and the torque generated by the starter 4 increases as compared with the torque characteristic A3, as indicated by the curve H shown in FIG. To do. Further, the starter current value (Ist) below the threshold value Ist2 increases, and the torque generated by the starter 4 increases compared to the torque characteristics A3 and B3.
[0065]
Next, the processing unit 11 determines whether or not the complete explosion determination flag of the engine has been turned ON (step ST307). If the complete explosion determination flag of the engine is not ON, the processing unit 11 returns to step ST304 and again starts the current value. (Ist) is read, the torque characteristic of the starter 4 is determined from the map 13 shown in FIG. 5A, and the circuit configuration of the torque characteristic determined by the variable means 43 is switched. On the other hand, when the complete explosion determination flag of the engine is ON, the engine has started, and the start control of the internal combustion engine is terminated.
[0066]
As described above, the torque characteristic of the starter 4 can be changed based on the rotational speed finer than the engine average rotational speed (Ne) for each constant crank angle by the rotational speed estimation means. Thereby, it is possible to accurately switch to a circuit configuration that generates the highest torque according to the actual engine speed, and in actuality even during a period in which the engine is rotating at a speed slower than the average speed, It is possible to switch to a circuit configuration that generates the highest torque, and to shorten the engine start time.
[0067]
[Fourth embodiment]
Next, an internal combustion engine start control method based on the average engine speed (Ne), which is the rotational speed detected by the rotational speed detection means, and the crank angle detected by the crank angle detection means will be described. FIG. 13 is a diagram showing an operation flow of the start control device for the internal combustion engine according to the fourth embodiment. FIG. 14 is a graph showing the relationship between the average engine speed (Ne) and the torque characteristics of the starter. This internal combustion engine start control method predicts the actual engine speed from the average engine speed (Ne). In the first and second embodiments, it has been described that the interval at which the detection target is provided on the crankshaft is narrowed and the average engine speed (Ne) may be a fine engine speed. In this case, the engine average engine speed ( After calculating (Ne), the torque characteristic of the starter 4 is changed, and therefore there is a possibility that it will be delayed from the timing of changing the actual torque characteristic. Therefore, it is necessary to store a map 13 as shown in FIG. 14A in the storage unit 12 of the circuit configuration switching means 1 in advance, and to predict the actual engine speed from the engine average speed (Ne). . Hereinafter, an operation flow when this predicting means is used will be described.
[0068]
First, as shown in FIG. 13, the ignition (I / G) is turned on, and the vehicle on which the engine is mounted is turned on (step ST401). Next, when the startability of the engine is reduced, such as at an extremely low temperature, the processing unit 11 of the circuit configuration switching unit 1 turns on the variable torque control execution flag (step ST402). Next, an initial torque characteristic (Ne = 0) is set (step ST403). That is, the processing unit 11 determines a torque characteristic (any one of A4, B4, and C4) from the map 13 shown in FIG. 14A based on the average engine speed (Ne), and variable means by the switching signal SW2. 43 is switched to a circuit configuration corresponding to the torque characteristic (any one of A4, B4, and C4).
[0069]
Next, the processing unit 11 reads ON / OFF (SW1) of the starter switch 6 and determines whether or not the starter 4 is ON (step ST404). If the starter 4 is ON, the average engine speed is determined. (Ne) is read (step ST405). If the starter 4 is OFF, the process returns to step ST402, and the operations of steps ST402 to 404 are repeated. Next, the processing unit 11 reads a map 13 that is a relationship between the crank angle (CA) and the engine average speed (Ne) shown in FIG. 14A from the storage unit 12 and determines whether there is a torque characteristic switching angle. Is determined (step ST406). For example, if the average engine speed (Ne) is Ne1, there is no torque characteristic switching angle, and if the average engine speed (Ne) is Ne2, it is determined that there is a torque characteristic switching angle. Next, processing unit 11 calculates torque characteristic switching angles (CA1 to CA8) from engine average speed (Ne) and map 13 and stores them in storage unit 12 (step ST407). Next, the processing unit 11 reads the crank angle (CA) detected by the crank angle detection means (step ST408), and the read crank angle (CA) is the torque characteristic switching angle (CA1 to 8). Whether or not (step ST409). Note that the torque characteristic switching angles (CA1 to CA8) are calculated values and therefore rarely completely coincide with the read crank angle (CA). In this case, it is preferable to determine whether or not the torque characteristic switching angle (CA1 to 8) is approximate to the read crank angle (CA).
[0070]
Next, if the read crank angle (CA) is the torque characteristic switching angle (CA1-8), the counter counts (n = 1-8) (step ST410), and the engine average speed (Ne). And torque characteristics corresponding to the torque characteristic switching angles (CA1 to CA8) are set (step ST411). That is, the processing unit 11 determines the torque characteristic (any one of A4, B4, and C4) of the starter 4 from the map 13 shown in FIG. 14A based on the average engine speed (Ne). Then, the processing unit 11 outputs a switching signal SW2 to the variable means 43, and the variable means 43 switches the circuit configuration based on the switching signal SW2. For example, when the average engine speed (Ne) is Ne2, the maximum torque generated by the starter 4 in the low rotation range as shown in FIG. The circuit configuration of the torque characteristic A4 is switched to the circuit configuration of the torque characteristic B4 in which the maximum torque generated by the starter 4 is low and the maximum rotation speed is high in the low rotation range. If the read crank angle (CA) is not the torque characteristic switching angle (CA1-8), the process returns to step ST408, and the operations up to steps ST408 and 409 are repeated.
[0071]
Next, it is determined whether or not the counter count is n = 8 (step ST412). If the count is n = 8, the processing unit 11 determines whether or not the complete explosion determination flag of the engine is turned on. Is determined (step ST413). On the other hand, if the count is not n = 8, the process returns to step ST408, and the operations of steps ST408 to 412 are repeated until the count reaches n = 8. If the complete explosion determination flag for the engine is not ON, the process returns to step ST404, and the operations of steps ST404 to 413 are repeated. That is, the engine average speed (Ne) is read again, the torque characteristic switching angle is determined from the map 13 shown in FIG. 10A, the torque characteristic of the starter 4 is determined, and the torque characteristic circuit determined by the variable means 43 is determined. Switch to configuration. On the other hand, when the complete explosion determination flag of the engine is ON, the engine has started, and the start control of the internal combustion engine is terminated.
[0072]
As described above, the map 13 shown in FIG. 14A is stored in the storage unit 12 of the circuit configuration switching unit 1 in advance, and the actual engine speed is predicted from the engine speed (Ne) to start the starter. 4 is changed. Thereby, after detecting the engine average rotation speed (Ne) for each constant crank angle by the rotation speed detection means, it is possible to follow the timing of changing the torque characteristic as compared with the case of changing the torque characteristic of the starter 4. Thus, the startability of the engine can be further improved. In the above embodiment, the case where the variable unit 43 switches the circuit configuration eight times has been described. However, the variable unit 43 has a circuit configuration depending on the type of engine (for example, the number of cylinders) that is an internal combustion engine started by the starter 4. The number of times of switching may be different.
[0073]
In all the embodiments described above, a plurality of circuit configurations are formed in the variable means 43 in order to change the torque characteristics of the starter 4, but the present invention is not limited to this. For example, the armature coil 42 is disposed between the field coil 41 and a separately provided shunt coil, and the starter 4 is controlled by a plurality of torques by controlling the shunt coil magnetic field in the same or opposite direction as the magnetic field of the field coil 41. You may make it change to a characteristic.
[0074]
Further, in the first and second embodiments, the interval at which the detection target is provided on the crankshaft is narrowed (for example, every 1 degree), and the average engine speed (Ne) is detected with a fine engine speed. Although described, the present invention is not limited to this. For example, as the engine average rotational speed (Ne), a rotational speed for each crank angle smaller than a certain crank angle estimated by the rotational speed estimation means may be used as in the third embodiment.
[0075]
【The invention's effect】
As described above, according to the start control device for an internal combustion engine (Claim 1) or the start control method for the internal combustion engine (Claim 7) according to the present invention, the torque required for rotating the internal combustion engine is low. Switch to a circuit configuration with torque characteristics (torque priority) that increases the torque generated by the starter in the rotation range, and torque that reduces the torque generated by the starter in the high rotation range where the torque required to rotate the internal combustion engine is small It is possible to switch to a circuit configuration of characteristics (rotational speed priority). Thereby, cranking can be performed in a wide rotation range from when the internal combustion engine is rotated to when the internal combustion engine is started, and even if the torque required to rotate the internal combustion engine at extremely low temperatures increases, The startability of the internal combustion engine can be improved. In addition, since the circuit configuration switching means switches the circuit configuration having a plurality of torque characteristics up to the number of revolutions required to start the internal combustion engine, the startup time of the internal combustion engine, particularly at a very low temperature, can be shortened. it can. As a result, the total electric power required for starting one internal combustion engine can be reduced, and the battery life can be extended or the battery can be downsized (use of a battery with a small capacity).
[0076]
Further, according to the start control device for an internal combustion engine according to the present invention (claim 2), the starter can be rotated at a low rotational speed even when the torque of the starter is small except at extremely low temperatures. The internal combustion engine is started with a circuit configuration having a torque characteristic (rotational speed priority) that reduces the generated torque. As a result, when starting the internal combustion engine at times other than extremely low temperatures, in addition to the operational effects of the start control device for the internal combustion engine, it is possible to suppress a decrease in riding comfort when starting the internal combustion engine.
[0077]
Further, according to the start control device for an internal combustion engine according to the present invention (claim 3), even if the power of the battery supplied to the starter is reduced at a very low temperature or due to deterioration of the battery, the internal combustion engine in a low rotation range. The internal combustion engine can be rotated by switching to a circuit configuration having torque characteristics (torque priority) necessary for rotating the engine. Thereby, even if the voltage of a battery falls, an internal combustion engine can be rotated and the startability of the internal combustion engine when the capacity | capacitance of a battery falls at the time of extremely low temperature or deterioration of a battery can be improved.
[0078]
Further, according to the start control device for an internal combustion engine according to the present invention (Claim 4), a heat storage system that operates according to an outside air temperature, a glow plug in a diesel engine, or a lubricating oil of an internal combustion engine whose viscosity resistance changes according to the outside air temperature, etc. The temperature of the internal combustion engine or the voltage of the battery is corrected in consideration of the factor that changes the torque required to rotate the internal combustion engine. As a result, the torque generated by the starter can be switched to a circuit mechanism having a torque characteristic that is at least equal to or greater than the minimum torque required to rotate the internal combustion engine, and the total electric power required for starting the internal combustion engine can be further reduced. Thus, the battery life can be extended or the battery can be further downsized.
[0079]
According to the start control device for an internal combustion engine according to the present invention (claim 5), the rotation speed estimation means estimates a rotation speed that is finer than the rotation speed for each constant crank angle detected by the rotation speed detection means. Thereby, it is possible to accurately switch to a circuit configuration that generates the highest torque according to the actual engine speed, and in actuality even during a period in which the engine is rotating at a speed slower than the average speed, It is possible to switch to a circuit configuration that generates the highest torque, and to shorten the engine start time.
[0080]
According to the internal combustion engine start control apparatus of the present invention (Claim 6), the actual engine speed is predicted from the engine speed detected by the engine speed detecting means, and the torque characteristic of the starter 4 is changed. . Thereby, after detecting the number of revolutions for each constant crank angle by the number of revolutions detection means, it is possible to follow the timing of changing the torque characteristic as compared with the case where the torque characteristic of the starter is changed. Can be further improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration example of a start control device for an internal combustion engine according to the present invention.
FIG. 2 is an operation explanatory diagram of variable means for forming a plurality of circuit configurations.
FIG. 3 is an operation explanatory diagram of variable means for forming a plurality of circuit configurations.
FIG. 4 is a diagram showing an operation flow of the start control device for the internal combustion engine according to the first embodiment.
FIG. 5 is a graph showing the relationship among engine average speed (Ne), engine cooling water temperature (Thw), and starter torque characteristics;
FIG. 6 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a modification of the first embodiment.
FIG. 7 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a modification of the first embodiment.
FIG. 8 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a modification of the first embodiment.
FIG. 9 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a second embodiment.
FIG. 10 is a graph showing a relationship among engine average speed (Ne), battery voltage (Vb), and torque characteristics of the starter.
FIG. 11 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a third embodiment.
FIG. 12 is a diagram showing a relationship between a starter current value (Ist) and a torque characteristic of the starter.
FIG. 13 is a diagram showing an operation flow of a start control device for an internal combustion engine according to a fourth embodiment.
FIG. 14 is a graph showing the relationship between the average engine speed (Ne) and the torque characteristics of the starter.
[Explanation of symbols]
1 Circuit configuration switching means
11 Processing unit
12 Storage unit
13 maps
2 ECU
3 Interface section
4 Starter
41 Field coil
42 Armature coil
43 Variable means
44 Branch wiring
45a-45c wiring
5 battery
6 Starter switch

Claims (7)

A starter that performs cranking at the start of the internal combustion engine; and a rotational speed detection unit that detects a rotational speed of the internal combustion engine or the starter, and controls the starter according to the rotational speed detected by the rotational speed detection unit. In an internal combustion engine start control device,
A plurality of circuit configurations in which the voltage required to drive the starter is constant and the torque characteristics of the starter are different;
Circuit configuration switching means for switching the circuit configuration according to the rotational speed;
An internal combustion engine start control device, wherein the circuit configuration switching means switches to a circuit configuration that generates the highest torque at the rotation speed detected by the rotation speed detection means. Temperature detecting means for detecting the temperature of the internal combustion engine,
When the temperature of the internal combustion engine detected by the temperature detection unit is higher than a predetermined temperature, the circuit configuration switching unit switches to a circuit configuration having a torque characteristic that reduces the generated torque in a low rotation range of the starter. The start control device for an internal combustion engine according to claim 1, wherein the start control device is an internal combustion engine. Battery voltage detecting means for detecting a voltage of a battery that supplies power to the starter;
The circuit configuration switching unit switches to a circuit configuration in which generated torque in a low rotation range of the starter is high when the voltage of the battery detected by the battery voltage detection unit is lower than a predetermined voltage. Item 3. The start control device for an internal combustion engine according to Item 1 or 2. A correction means for correcting the temperature of the internal combustion engine detected by the temperature detection means or the battery voltage detected by the battery voltage detection means;
The start control of the internal combustion engine according to claim 2 or 3, wherein the circuit configuration switching unit switches the circuit configuration based on the temperature of the internal combustion engine or the voltage of the battery corrected by the correction unit. apparatus. A starter that performs cranking at the start of the internal combustion engine, and a rotational speed detection means that detects the rotational speed of the internal combustion engine or the starter at every constant crank angle, according to the rotational speed detected by the rotational speed detection means In the internal combustion engine start control device for controlling the starter,
A plurality of circuit configurations in which the voltage required to drive the starter is constant and the torque characteristics of the starter are different;
A rotational speed estimating means for estimating the rotational speed for each crank angle smaller than the constant crank angle;
Circuit configuration switching means for switching the circuit configuration according to the rotational speed estimated by the rotational speed estimation means;
An internal combustion engine start control device, wherein the circuit configuration switching means switches to a circuit configuration that generates the highest torque at the rotational speed estimated by the rotational speed detection means. A starter for cranking at the start of the internal combustion engine; crank angle detection means; and a rotation speed detection means for detecting the rotation speed of the internal combustion engine or the starter at every predetermined crank angle. In the internal combustion engine start control device for controlling the starter according to the rotation speed,
A plurality of circuit configurations in which the voltage required to drive the starter is constant and the torque characteristics of the starter are different;
Circuit configuration switching means for switching the circuit configuration according to the rotational speed detected by the rotational speed detection means and the crank angle detected by the crank angle detection means;
The circuit configuration switching means switches to a circuit configuration that generates the highest torque at the rotation speed detected by the rotation speed detection means and the crank angle detected by the crank angle detection means. Engine start control device. A step of determining ON / OFF of a starter that performs cranking at the start of the internal combustion engine;
Detecting the rotational speed of the internal combustion engine or the starter when the starter is ON;
Switching the starter at a constant voltage to a torque characteristic that generates the highest torque at the detected rotational speed;
Determining a complete explosion of the internal combustion engine;
A start control method for an internal combustion engine, comprising:

Images