JP3985621B2 - ENGINE START DEVICE, START CONTROL DEVICE, START SYSTEM, AND START METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine starter, a start control device, a start system, and a start method that are excellent in durability, quietness, and the like, and in particular, excellent in engine startability after idling stop.
[0002]
[Prior art]
With the recent increase in awareness of environmental issues, a major theme for research and development is to reduce emissions by improving the fuel efficiency of automobiles. As part of this, it has come to stop an engine of a car or the like during idling (so-called idling stop). In particular, such idling stops are frequently performed when driving in urban areas where go-stops are repeated.
The problem here is starting after idling stop.
Conventionally, the start of an automobile engine or the like has been performed by a gear type starter assuming only the start at the beginning of traveling. In general gear type starters, a pinion gear is temporarily meshed with a driven gear (ring gear, etc.) connected to an engine output shaft (crankshaft, etc.), and the pinion gear is driven by a motor to rotate the crankshaft etc. Is.
[0003]
If such a gear starter is also used for starting after the idling stop described above, unpleasant noise such as gear ringing can frequently occur every time. In addition, since the number of start-ups (frequency of use) increases rapidly, it is difficult to guarantee sufficient durability, reliability, etc. in the conventional gear type starter.
Therefore, in an automobile or the like that stops idling, the engine is often started after idling is stopped by a belt type starter that is excellent in quietness and reliability. In this belt type starter, for example, a driven pulley (crank pulley or the like) provided separately from the ring gear or the like is driven by a motor via a belt and a starter pulley to rotate a crankshaft or the like.
[0004]
By the way, in the case of a belt type starter, the reduction ratio is determined by the pulley diameter ratio with which the belt is linked, but it is usually difficult to obtain a large reduction ratio. Of course, it is also difficult to increase the size of the belt type starter because it is against the demand for overall light weight and size. The situation is the same even when a motor generator (motor generator: MG) used in an electric vehicle, a hybrid vehicle or the like is used instead of the belt type starter. For this reason, it is difficult to obtain a sufficient starting torque with only a belt type starter or MG. In addition, the torque required for starting the engine differs depending on the state of the engine. For example, a larger starting torque is required at a cold time or a high temperature than at a warm time. In order to ensure the startability in such a case, a gear type starter having a high reduction ratio is usually added to the belt type starter.
For example, Japanese Patent Application Laid-Open No. 10-68374 and Japanese Patent Application Laid-Open No. 2001-2001 include a method of using both starters according to the starting torque required for starting the engine, or using both together or cooperating to start the engine. No. 152901, JP 2001-159384 A, JP 2001-107763 A, JP 2002-48036 A, and the like.
[0005]
[Problems to be solved by the invention]
However, in the conventional cases where both starters are used together to start the engine, the gear starter having a large output torque can be started alone.
For this reason, the gear type starter is naturally limited in size from the viewpoint of securing its output. Also, considering the use of a gear type starter at the start after idling stop, there is a difference in frequency due to the difference in control method, and the gear type starter requires higher reliability than before. The Rukoto.
[0006]
The present invention has been made in view of such circumstances. In other words, when starting the engine mainly with a starter where it is difficult to achieve both a high reduction ratio and downsizing, such as a belt-type starter, the overall downsizing and quietness are ensured while ensuring startability. An object of the present invention is to provide an engine starting device, a starting control device, a starting system, and a starting method that can ensure reliability and the like.
[0007]
[Means for Solving the Problems and Effects of the Invention]
The present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, the inventor has come up with the idea that the starter attached to the belt-type starter etc. is used only as an auxiliary for the belt-type starter, etc., with little rotation The present invention has been completed.
(Engine starter: Claim 1)
That is, the engine starter according to the present invention includes a main starter capable of rotating the engine output shaft to at least the necessary rotational speed necessary for starting the engine, and a low rotational speed lower than the initial rotational speed of the engine output shaft or the required rotational speed. An assist starter that substantially functions only in several regions and assists the main starter, and the assist starter has a rotational torque within a range in which the output shaft is not substantially rotated at the beginning of the rotation of the engine output shaft. Is applied to the output shaft to reduce the rotational load of the main starter .
[0008]
In the engine starter according to the present invention, the main starter is mainly responsible for starting the engine. However, with only the main starter, there is a case where the torque is insufficient when the engine output shaft is rotated. At this time, the assist starter assists the main starter to ensure smooth engine startability by the main starter.
Here, the assist starter does not need to ensure engine startability by itself, and the assist starter can be downsized accordingly.
Since this assist starter substantially functions only at the beginning of rotation of the engine output shaft or in a low rotation speed range lower than the necessary rotation speed required for engine start, a sliding portion or the like (for example, a motor brush) There is almost no wear in the commutator and the like, and excellent durability is ensured.
[0009]
Further, even when the assist starter is constituted by a gear type starter, for example, the gear type starter hardly rotates, so that the generation of abnormal noise such as gear ringing is suppressed and prevented. In particular, if the main starter is a belt-type starter, a motor generator (MG), or the like, the starter as a whole is further excellent in quietness (Claim 2 ).
The starting device of the present invention is suitable not only for starting the engine at the start of operation (or starting the engine when cold) but also for starting the engine after idling stop .
[0010]
By the way, the assist starter is more specifically as follows.
The assist starter is, for example, torque reducing means for applying a rotational torque in a range in which the output shaft is not substantially rotated at the beginning of rotation of the engine output shaft to reduce the rotational load of the main starter. There is .
When the engine output shaft is rotated to start the engine, a large torque (rotation start torque) is required at the beginning of the rotation. This is due to the fact that when each sliding part starts moving, a large static frictional force acts on each part and the initial carryover torque is large. Conversely, after the beginning of this rotation, the frictional force of each sliding part is replaced by a dynamic frictional force that is considerably smaller than the static frictional force, and inertia also acts. Therefore, the torque (rotation required for continued rotation of the engine output shaft) (Continuation torque) can be small. Therefore, even when the engine output shaft starts to rotate, if the assist starter (torque mitigation means) acts and the rotational load on the main starter is reduced, the main starter is assumed to have a low output torque with a reduced speed ratio. However, the engine can be started only with the main starter. Here, the overpass torque is a rotation start torque necessary for starting rotation of the engine output shaft. Strictly speaking, it is a torque that not only overcomes the static frictional force but also allows the engine output shaft to continue rotating against the compression force and the like. The overpass torque includes a low temperature overpass torque and a high temperature overpass torque. Usually, the low temperature overpass torque is larger than the high temperature overpass torque.
[0011]
By the way, the above-mentioned torque reducing means is specifically various actuators, gear type starters, and the like. The actuator is not limited to rotating, but may be linear. This is because it is sufficient if the rotational torque can be applied in a small region at the beginning of the rotation of the engine output shaft.
In the case of a gear type starter, a conventionally used gear type starter may be used, or a dedicated gear type starter may be used. In any case, since it is not substantially rotated, there is no problem with the durability and reliability of the gear type starter. In order to prevent the starter from being substantially rotated while using the conventional gear type starter, for example, the voltage applied to the starter may be controlled. The drive source of the gear type starter may be a direct current motor or an alternating current motor. However, if a battery is used as a power source, the direct current motor is easier to handle. At this time, as described above, since it does not substantially rotate, it is not necessary to consider brush wear or the like.
Further, since such a torque reducing means does not need to directly rotate the engine output shaft, it can be very downsized whether it is an actuator or a gear starter. In particular, if a motor is used, a large output torque can be obtained while reducing the size by flowing a lock current at the beginning of rotation of the engine output shaft.
[0012]
Next, the assist starter may be an angular displacement means for angularly displacing the output shaft from a stop position to a predetermined position at which the engine can be started by the main starter .
The rotation starting torque varies depending on the stop position of the engine output shaft. For example, if the engine is in the compression stroke, a larger torque is required to rotate the engine output shaft. Therefore, the assist starter (angular displacement means) temporarily rotates (angular displacement) the engine output shaft to a position where the rotation of the engine output shaft by the main starter becomes easy.
As a result, the main starter can reduce the rotational load required at the beginning of rotation of the engine output shaft and facilitate rotation of the engine output shaft. At this time, the assist starter may rotate the engine output shaft forward or backward depending on the stop position of the engine output shaft.
However, not only when the engine output shaft is rotated to a position where the rotation start torque is reduced, but conversely, the engine output shaft is rotated with an assist starter to advance the compression stroke of the engine, where temporary ignition and explosion occur. It is also possible to cause the engine to start. The main starter in this case is composed of a fuel injection device, an ignition device, and their control devices.
As for the stop position of the engine output shaft, for example, a bar code or a magnetic resistance that is detected differently for each angular position is arranged in a ring on a member that rotates together with the engine output shaft. This can be done by detecting with a detector. Further, the actuator, the gear type starter, etc. can be used as the angular displacement means as in the case of the torque reduction means.
[0013]
Further, the assist starter may be a low speed starter that rotates the engine output shaft only in the low rotation speed range .
As described above, when starting the engine, a large torque is required at the beginning of the rotation of the engine output shaft. Therefore, if the assist starter rotates the engine output shaft only in the low rotation speed range, it becomes easy to continue the engine output shaft starting rotation by the main starter thereafter. At this time, since the assist starter is used only in the low rotation speed region at the beginning of the rotation of the engine output shaft, durability and the like are not so much a problem and can be reduced in size. In order to obtain high torque while further downsizing, the assist starter in this case is preferably a gear type starter capable of increasing the reduction ratio. The motor itself used for the low speed starter may be a high speed type.
[0014]
(Engine start control device )
The present invention can be grasped not only as the engine starting device but also as an engine starting control device.
That is, the present invention controls the energization to the assist starter that assists the main starter that can rotate the engine output shaft to at least the necessary rotational speed necessary for starting the engine, and starts the rotation of the engine output shaft or the necessary rotation. The engine start control device may be characterized in that the assist starter is substantially operated only in a low rotational speed range lower than the number.
[0015]
(Engine starting system )
In addition to the above, the present invention can be grasped as an engine starting system.
That is, the present invention provides a main starter capable of rotating the engine output shaft to at least a necessary rotational speed necessary for starting the engine, an assist starter for assisting the main starter, and energization to the assist starter to control the engine output. An engine start system comprising: a start control device that substantially operates the assist starter only at the beginning of shaft rotation or in a low speed range lower than the required speed.
[0016]
(How to start the engine )
In addition to the above, the present invention can be grasped as an engine starting method.
That is, the present invention controls the energization to the assist starter that assists the main starter that can rotate the engine output shaft to at least the necessary rotational speed necessary for starting the engine, and starts the rotation of the engine output shaft or the necessary rotation. The engine start method may be characterized in that the assist starter is substantially operated only in a low rotational speed range lower than the number.
[0017]
It should be noted that the description of the “engine starter” is applicable as appropriate to any of the engine start control device, the start system, and the start method.
As long as the engine as used in this invention requires a starter for the start-up, the kind of engines, such as a gasoline engine, a diesel engine, a rotary engine, is not ask | required. Further, the vehicle or the like on which the engine is mounted is not limited to an automobile but may be a two-wheeled vehicle, a special vehicle, or the like.
The arrangement of the main starter and assist starter is not limited. For example, when the main starter is a belt type starter, it is provided in front of the engine, and when the assist starter is a gear type starter, it is provided behind the engine. The belt-type starter may be driven by a starter-dedicated belt, may be driven by a belt that is also used as another auxiliary machine, or may be driven by a timing belt or the like.
[0018]
The gear type starter may have the same structure as a conventional gear type starter, but may also have a structure dedicated to an assist starter. For example, since a gear type starter used only at the beginning of rotation of the engine output shaft does not substantially rotate, there is no need for a normally provided one-way clutch or the like. In addition, since the gear type starter does not necessarily need to continuously rotate the engine output shaft, the number of teeth of the pinion gear is only a few that are initially engaged, and the other teeth may be missing. In this case, the pinion gear does not necessarily have to be a fly-out type.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to embodiments.
(First embodiment)
FIG. 1 shows an overall schematic diagram of an engine start system according to a first embodiment of the present invention.
The starting system includes a main starter Sm disposed in front of a four-cylinder reciprocating gasoline engine E (hereinafter simply referred to as “engine E”), an assist starter Sa disposed behind the main starter Sa, and a power source for these. The operation of the battery (DC power supply), the main side relay Rm for switching energization from the battery to the main starter Sm, the assist side relay Ra for switching energization to the assist starter Sa, the main side relay Rm and the assist side relay Ra It consists of a start controller C (start control device) to be controlled and wiring for connecting them.
[0020]
The main starter Sm is a belt type starter. That is, the starter pulley Ps is attached to the output shaft of the reduction gear provided on the front end side of the DC motor as a drive source. A V belt is suspended between the starter pulley Ps and a crank pulley Pc attached to a front end portion of a crankshaft CR (engine output shaft) of the engine E. As a result, the crankshaft CR of the engine E is started and rotated.
[0021]
The assist starter Sa is a normal gear starter. In other words, a pinion gear that is driven by a magnet switch (also serving as an assist-side relay Ra) is connected to the output shaft of a reduction gear provided on the front end side (the rear end side of the engine E) using a DC motor as a drive source. Installed. The pinion gear jumps out to the rear end side of the engine E at the time of starting and meshes with a ring gear attached to the rear end portion of the crankshaft CR of the engine E. At least rotational torque is applied to the crankshaft CR by the pinion gear and the ring gear.
[0022]
The start controller C performs not only start control of the engine E at the start of vehicle operation, but also start control (eco-run control) after the arid ring stop during vehicle operation. Furthermore, the start controller C of this embodiment controls not only the switching control of each relay described above, but also the voltage applied to the assist starter Sa.
Next, start control by the start controller C in the start system will be described with reference to the flowchart of FIG.
When a signal for turning on a start switch such as an ignition switch is input (step S1), the start controller C first turns on the assist side relay Ra (step S2). At this time, the start controller C controls the applied voltage to the assist starter Sa to be lower (step S3) and starts energizing the assist starter Sa (step S4).
[0023]
Incidentally, since the assist starter Sa is a starter similar to the conventional one, the assist-side relay Ra is built in the magnet switch, and the magnet switch itself is also turned on when the assist-side relay Ra is turned on. Then, the above-described pinion gear is pushed out by the electromagnetically driven lever and is ejected and meshed with the ring gear.
Here, when a normal battery voltage (for example, 12 V) is applied to the assist starter Sa, the engine E can be started alone. However, here, a voltage is applied by voltage control so that the assist starter Sa does not start rotating. For this reason, a lock current flows through the assist starter Sa for a very short time (usually several ms), and the assist starter Sa outputs a torque proportional to the applied voltage to the ring gear, and thus the crankshaft CR.
[0024]
Next, the start controller C turns on the main relay Rm (step S5) and starts energizing the main starter Sm (step S6). At this time, the voltage applied to the main starter Sm is a battery voltage. Then, when the crankshaft CR starts rotating and exceeds the initial carryover torque and the rotational speed becomes equal to or higher than the predetermined rotational speed (N ₀ ) (step S7), the assist side relay Ra is turned off (step S8). Then, the energization to the assist starter Sa is stopped (step S9). Thereafter, when the crankshaft CR is started and rotated (cranked) only by the main starter Sm, and the engine E is considered to have started when the engine speed reaches or exceeds a predetermined engine speed (N ₁ ) (step S10), The side relay Rm is turned off (step S11), and the energization to the main starter Sm is stopped (step S12). Thus, the start of the engine E is completed.
FIG. 3 shows a time chart of ON / OFF of each relay during start control, applied voltage to each starter, combined torque applied to the crankshaft CR, engine speed, and the like.
[0025]
In the case of the present embodiment, the conventional gear type starter is used as an assist starter Sa, which is also used auxiliary for starting after idling stop. However, since the gear type starter hardly rotates, there is no problem regarding durability such as brush wear. Since this gear type starter only provides torque assist at the start of the engine E, there is almost no unpleasant noise such as gear noise. Since the engine E is started mainly by the main starter Sm composed of a belt type starter, the engine can be started very quietly.
[0026]
(Second Embodiment)
A wiring diagram and a time chart of the engine starting system according to the second embodiment of the present invention are shown in FIGS. 4 and 5, respectively.
In the present embodiment, the assist starter Sa is changed from the conventional gear starter used in the first embodiment to a small gear starter having a small output torque. For this reason, even if the entire voltage of the battery is applied to the assist starter Sa, the engine E cannot be started alone. In other words, it is not necessary to control the voltage applied to the assist starter Sa by the start controller C as in the first embodiment. Therefore, in this embodiment, as is apparent from FIG. 4, the wiring is applied directly from the battery to the assist starter Sa.
As described above, by using a small gear starter as the assist starter Sa, the starter controller C and the wiring structure can be simplified while the starter system can be reduced in weight and size.
[0027]
(Third embodiment)
A wiring diagram and a time chart of the engine starting system according to the third embodiment of the present invention are shown in FIGS. 6 and 7, respectively.
In the present embodiment, the assist starter Sa is the same as that of the first embodiment, but the wiring is changed so that a voltage is directly applied to the assist starter Sa from the battery. Further, a crank angle sensor D for detecting the crank angle of the crankshaft CR is attached to the engine E. The detection signal from the crank angle sensor D is taken into the start controller C. The crank angle sensor D can be constituted by a magnetic pickup, for example.
The start controller C first turns on the assist relay Ra to slightly activate the assist starter Sa. As a result, the crankshaft CR starts to rotate. However, when the crankshaft CR rotates to a predetermined position set in advance and receives a detection signal from the crank angle sensor D, the start controller C turns on the main side relay Rm and immediately after that turns on the assist side relay Ra. Turn off. Then, the engine E is started only by the main starter Sm.
[0028]
The position detected by the crank angle sensor D is a position at which the torque (rotation start torque) necessary to rotate the crankshaft CR is substantially minimized. Even if it is a belt type starter (main starter Sm) having a smaller reduction ratio and output torque than the gear type starter, the engine can be easily started from that position. Further, at this time, since the assist starter Sa (angular displacement means) only rotates the crankshaft CR at most several times, its durability and quietness do not become a problem.
In the present embodiment, the case where the main starter Sm is a belt type starter has been described. However, the main starter Sm can be replaced by temporarily igniting and exploding the engine E. At this time, the electronic control unit (ECU) of the engine E cooperates with the start controller C to adjust the injection timing of the fuel injection valve of the engine E and the ignition timing of the spark plug according to the rotation of the assist starter Sa.
[0029]
(Fourth embodiment)
The wiring diagram and time chart of the engine starting system according to the fourth embodiment of the present invention are shown in FIGS. 8 and 9, respectively.
In the present embodiment, the assist starter Sa is replaced with an electromagnetic actuator from the conventional gear starter used in the first embodiment or the like. This electromagnetic actuator does not rotate and output like a conventional gear starter, but outputs linearly like a linear motor. By disposing this electromagnetic actuator on the outer periphery of the crankshaft CR, rotational torque can be applied to the crankshaft CR (torque reducing means). Of course, it goes without saying that the crankshaft CR cannot be substantially rotated except for a very small amount.
If such an electromagnetic actuator is used, it is easy to adjust the rotational torque applied at the beginning of the start. As an example, FIG. 9 illustrates a case where the initial voltage applied thereto is increased linearly.
[0030]
(Other)
Although the case where the assist starter Sa is hardly rotated has been described in the first embodiment, the assist starter Sa may be rotated at a low speed by voltage control by the start controller C. Because of the low speed rotation, the durability and quietness of the gear type starter are not substantially a problem. The assist starter Sa at this time corresponds to the low speed starter referred to in the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an outline of an engine start system according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing start control by the start controller.
FIG. 3 is a timing chart at that time.
FIG. 4 is a wiring diagram of an engine start system according to a second embodiment of the present invention. FIG. 5 is a timing chart at that time.
6 is a wiring diagram of an engine start system according to a third embodiment of the present invention. FIG. 7 is a timing chart at that time.
FIG. 8 is a wiring diagram of an engine start system according to a fourth embodiment of the present invention. FIG. 9 is a timing chart at that time.
[Explanation of symbols]
Sm Main starter Sa Assist starter Rm Main side relay Ra Assist side relay C Start controller E Engine CR Crankshaft (engine output shaft)
Ps Starter pulley Pc Crank pulley B Belt

Claims (2)

A main starter capable of rotating the engine output shaft to at least the necessary number of revolutions necessary for engine startup;
An assist starter that substantially functions only at the beginning of rotation of the engine output shaft or in a low rotational speed range lower than the required rotational speed and assists the main starter ,
The assist starter is torque reducing means for reducing a rotational load of the main starter by applying a rotational torque in a range in which the output shaft is not substantially rotated at the beginning of rotation of the engine output shaft to the output shaft. An engine starting device. The main starter is a belt type starter or a motor generator,
The engine starter according to claim 1, wherein the assist starter is a gear type starter.

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