Control device for vehicle

Abstract

To make it possible to easily estimate the cause of fluctuations in engine rotation speed and take measures against the fluctuations.SOLUTION: A controller for monitoring the fluctuation range of a rotation speed of an internal combustion engine comprises: a rotation fluctuation detection unit for detecting that the fluctuation range of the rotation speed of the internal combustion engine exceeds a reference range (step S3); a maintenance action detection unit for detecting that a maintenance action including either the supply of fuel to the internal combustion engine or the supply of lubrication oil to the internal combustion engine or a transmission mechanism is performed and information on the execution time of the maintenance action (steps S5, S7); and a memory unit that, when the rotation fluctuation detection unit detects that the fluctuation range of the rotation speed of the internal combustion engine exceeds the reference range, stores the content of the maintenance action performed immediately before the detection and information on the execution time of the maintenance action, and can output the stored contents to the outside (steps S6, S8).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a device for detecting fluctuations in the rotation speed of an internal combustion engine (hereinafter referred to as an engine) mounted on a vehicle as a driving force source, and for taking measures against the detected rotation speed fluctuations. [Background technology]

[0002] Since an engine outputs power by intermittently burning a mixture of fuel and air, the output torque and rotation speed inevitably change intermittently. For this reason, a damper is provided on the output side of the engine to suppress the fluctuations in the output torque and rotation speed. On the other hand, if a spring damper is provided, the engine and the spring damper form a vibration system, and if the spring characteristics are inappropriate, the fluctuations in the engine rotation speed may increase due to resonance. As a device for solving such inconvenience, Patent Document 1 describes a device that forms a dynamic damper by connecting a motor via a spring to a rotating element to which the engine power is transmitted, and is configured to switch the embodiment of the gear rattle suppression control that suppresses the gear rattle caused by the engine rotation fluctuation based on the spring characteristics of the dynamic damper.

[0003] The rattle suppression control is a control for reducing abnormal noise (rattle or rattle) caused by separation and contact of tooth surfaces in a gear-type transmission mechanism such as a transmission connected to the output side of the engine, and is a control for changing an operating point determined by the engine speed and output torque so that the rattle caused by fluctuations in the speed falls within an acceptable range. The device described in Patent Document 1 acquires changes in spring characteristics and spring characteristics based on the temperature of the dynamic damper, the rotational behavior of the output side member, or changes over time of the dynamic damper, and determines an embodiment of the rattle suppression control based on the spring characteristics. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-51708 A Summary of the Invention [Problem to be solved by the invention]

[0005] The device described in Patent Document 1 can be said to be a device configured to adapt the embodiment of the rattle suppression control to the spring characteristics of the dynamic damper. A device configured in this way is effective when a change in the spring characteristics is detected, but it is not possible to know the cause or factor that causes such a change. Therefore, the device described in Patent Document 1 may not be able to fundamentally eliminate the cause of the engine speed fluctuation, and there is still room for improvement in this respect.

[0006] The present invention has been made in consideration of the above-mentioned technical problems, and aims to provide a vehicle control device that makes it possible to easily estimate the cause of engine speed fluctuations and take measures to address the cause. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a control device for a vehicle equipped with an internal combustion engine and a gear-type transmission mechanism that transmits the power output by the internal combustion engine, and that changes an operating point of the internal combustion engine when the fluctuation range of the rotation speed of the internal combustion engine exceeds a predetermined standard range, the control device comprising a controller that monitors the fluctuation range of the rotation speed of the internal combustion engine, the controller comprising a rotation fluctuation detection unit that detects that the fluctuation range of the rotation speed of the internal combustion engine has exceeded the standard range, a maintenance measure detection unit that detects that a maintenance measure has been performed, including either the supply of fuel to the internal combustion engine or the supply of lubricating oil to the internal combustion engine or the transmission mechanism, and information on the timing of the maintenance measure, and a memory unit that, when the rotation fluctuation detection unit detects that the fluctuation range of the rotation speed of the internal combustion engine has exceeded the standard range, stores the content of the maintenance measure performed immediately before the detection and information on the timing of the execution of the maintenance measure, and is capable of outputting the stored content to the outside. Effect of the Invention

[0008] According to the present invention, when the fluctuation range of the rotation speed of the internal combustion engine exceeds a predetermined reference range, the content of the maintenance measure performed immediately before that and the execution time information are stored. The detection of the fluctuation range of the rotation speed of the internal combustion engine is performed when a predetermined stable operation condition is established, such as during idling operation after warming up is completed. The fluctuation range of the rotation speed can be obtained as the difference between the maximum value (local maximum value) and the minimum value (local minimum value) of the rotation speed of the internal combustion engine during a predetermined time period. When it is detected that the fluctuation range of the rotation speed of the internal combustion engine exceeds the predetermined reference range, the content of the maintenance measure performed immediately before the detection and the execution time information are stored, so that the stored maintenance measure is considered to be the cause of the increase in the fluctuation range of the rotation speed of the internal combustion engine. Then, the stored content of the maintenance measure and the execution time information can be output to the outside, so that it is possible to take measures against the cause of the increase in the fluctuation range of the rotation speed of the internal combustion engine, such as removing the cause. As a result, it becomes possible to avoid or suppress a re-increase in the fluctuation range of the rotation speed of the internal combustion engine, as well as a breakdown or a decrease in the durability of the internal combustion engine or the power transmission mechanism. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing an engine and a transmission as a power transmission mechanism according to an embodiment of the present invention. [Diagram 2] 4 is a diagram showing equal power lines, optimal fuel consumption lines, and gear rattle suppression operation lines; FIG. [Diagram 3] FIG. 2 is a block diagram showing a functional configuration of a controller according to the embodiment of the present invention. [Figure 4] 4 is a flowchart illustrating a control executed in the embodiment of the present invention. [Diagram 5] 10 is a diagram showing a schematic diagram of a predetermined range defined as a judgment criterion for a warm-up time; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Next, the present invention will be described based on the embodiment shown in the drawings. Note that the embodiment described below is merely one example of a specific embodiment of the present invention, and is not intended to limit the present invention.

[0011] The vehicle targeted by the present invention is a vehicle equipped with an internal combustion engine and a gear-type transmission mechanism that transmits the power output by the internal combustion engine. The internal combustion engine is a power engine that outputs mechanical power by burning a mixture of fuel and air, and examples of the internal combustion engine include a gasoline engine and a diesel engine. Hereinafter, the internal combustion engine will be referred to as an engine. The vehicle may use only this type of engine as a driving power source, but is not limited to this, and may be a so-called hybrid vehicle (HEV, PHV) in which the driving power source is configured together with an electric motor (motor). The transmission mechanism is a mechanism in which at least a part of the members that transmit torque is configured by gears, and a typical example is a stepped transmission, or a power split mechanism consisting of a planetary gear mechanism that splits the power output by the engine.

[0012] 1 shows a schematic diagram of an engine (ENG) 1 and a transmission (T / M) 2 connected to its output side, and the engine 1 is configured to mix fuel (e.g., gasoline) pumped from a fuel tank 3 with air and supply the fuel to a cylinder (not shown), or to spray the fuel directly into the cylinder. A fuel sensor 4 is provided to detect the remaining amount of fuel in the fuel tank 3 in order to inform the driver that the fuel in the fuel tank 3 is low or that refueling is required. This fuel sensor 4 may be a sensor similar to that employed in conventional vehicles.

[0013] The mixture of fuel and air burns properly within a specified temperature range, and since an excessively high temperature of the engine 1 can cause problems with strength and durability, the engine 1 is water-cooled. A water temperature sensor 5 is provided to detect the temperature of the cooling water used for the engine 1 as the engine temperature.

[0014] The output torque and output speed (engine speed), which change according to the intake air amount (or throttle opening), are determined for the operating point of the engine 1. In order to operate the engine 1 at an operating point according to a request, a speed sensor 6 is provided to detect the engine speed.

[0015] Engine 1 has many points that require lubrication, such as the contact points between pistons (not shown) and cylinders, the bearings of the crankshaft (not shown), the intake and exhaust valves, and the shafts that drive these (not shown), and is configured to supply lubricating oil (not shown) stored in an oil pan 7 to each of these lubricating parts as needed. Since the lubricating oil is gradually consumed by operating engine 1, an oil sensor 8 is provided to issue a warning when the amount of lubricating oil is insufficient. Note that lubricating oil gradually deteriorates, so it is generally necessary to replace it periodically or after a specified mileage.

[0016] The transmission 2 may be either a stepped or a continuously variable transmission, but at least a part of the transmission is provided with gears, which transmit torque. If torque is constantly transmitted from the driving gear to the driven gear, the tooth surfaces maintain contact with each other, but if the rotation speed of the driving gear fluctuates for some reason, the teeth that were in contact with each other will momentarily separate, and immediately after that, the teeth will contact each other again. When such separation and contact between the teeth occurs, the impact of the contact generates a sound, which is an abnormal sound known as a teeth rattle or rattle. In the transmission 2, such contact between the teeth of the gears and the associated sliding occurs, and there are many other parts, such as rotating parts, that require lubrication. For this reason, the transmission 2 is lubricated by lubricating oil, just like the engine 1. A sensor is provided to detect whether the amount of lubricating oil is within an appropriate range. The sensor may be shared with the oil sensor 8 of the engine 1 described above.

[0017] Furthermore, the viscosity of the lubricating oil in the engine 1 and the transmission 2 decreases when the temperature rises to a certain level (i.e., when the engine and the transmission are warmed up), and the lubricating oil can perform its original lubricating function. Also, if the temperature is too high, not only will the lubricating function decrease, but the durability will also decrease. For this reason, an oil temperature sensor 9 is provided to detect the temperature of the lubricating oil.

[0018] The engine 1 is controlled to have good fuel economy within a range that satisfies the drive demand represented by the accelerator opening degree and the like. For example, in a two-motor hybrid vehicle or a vehicle equipped with a continuously variable transmission, the throttle opening degree and the gear ratio are automatically controlled to satisfy the drive demand. That is, when the accelerator opening degree increases, the throttle opening degree is increased and the gear ratio of the transmission mechanism is decreased according to the increase in the engine speed to suppress the increase in the engine speed. FIG. 2 shows the equal power line Pi and the optimal fuel economy line Ofc with the engine torque Te on the vertical axis and the engine speed Ne on the horizontal axis. When the vehicle is running steadily, the engine 1 is operated at the operating point (output torque and engine speed) represented by the intersection of the equal power line Pi and the optimal fuel economy line Ofc, which are determined based on the drive demand.

[0019] Such engine control is executed by an engine controller (hereinafter, simply referred to as the controller) mainly composed of a microcomputer. The controller is input with data indicating the vehicle's running state, such as the accelerator opening and vehicle speed, and also stores control data, such as the optimum fuel consumption line shown in Fig. 2, in advance. The controller is configured to perform calculations based on these data to control the throttle opening (output torque) and the gear ratio (engine speed).

[0020] On the other hand, since the engine 1 generates power by intermittently burning a mixture of fuel and air, the output torque and rotation speed of the engine 1 inevitably fluctuate. For this reason, a damper (not shown) is provided to suppress the fluctuation of the output torque and rotation speed within an allowable range. However, due to some factor such as unstable combustion or increased friction, the fluctuation range of the rotation speed may exceed the reference range. In such a case, rattle noise may occur in the gears constituting the transmission mechanism such as the transmission 2, so rattle noise suppression control is executed to avoid or suppress the rattle noise. This control is a control to reduce the engine torque Te and increase the engine speed Ne, and the larger the engine speed fluctuation, the greater the amount of reduction in the engine torque Te and the greater the amount of increase in the engine speed Ne. FIG. 2 also shows a schematic diagram of the rattle noise suppression operation line Li used in the rattle noise suppression control. Here, the fluctuation range (amount of fluctuation) of the engine speed may be the difference ΔNepre between the maximum value (maximum value) and the minimum value (minimum value) of the engine speed within a predetermined time. In the example shown in FIG. 2, the rattle noise suppression operation line Li is set to the lower torque / higher rotation speed side as the fluctuation range of the engine speed becomes larger. This can be obtained in advance based on experiments, simulations, etc. Also, the rattle noise suppression control can be executed by the above-mentioned controller.

[0021] The embodiment of the present invention is configured to execute control for estimating the cause when the engine speed fluctuation range becomes large and the above-mentioned rattle suppression control is executed, or when the execution of the rattle suppression control is predicted. The control can be configured to be executed by the above-mentioned controller. The functional configuration of the controller 10 for executing control for detecting or estimating the cause (or factor) of the rattle is shown in a block diagram in FIG. 3. The engine speed of the engine 1 changes due to an acceleration request, warming up, etc., so in that state, it is not possible to detect the fluctuation of the engine speed due to an unintended cause or factor. Therefore, it is necessary to determine whether a so-called stable condition for stabilizing the engine speed of the engine 1 is satisfied, and therefore the controller 10 is provided with a control condition determination unit 10a for determining whether the so-called stable condition is satisfied. Here, the stable condition is, for example, that the engine 1 has finished warming up and is idling.

[0022] The controller 10 includes a rotational fluctuation detection unit 10b that detects the fluctuation width of the rotational speed of the engine 1 when the stable condition is satisfied. The engine speed is constantly input to the controller 10 from the above-mentioned rotational speed sensor 6, and the rotational fluctuation detection unit 10b obtains the difference ΔNepre between the maximum value (local maximum value) and the minimum value (local minimum value) of the engine speed within a predetermined time based on the data, and judges whether the rotational speed difference ΔNepre is equal to or greater than a predetermined value. The predetermined value can be obtained in advance by experiment, simulation, or the like as the rotational speed difference that may cause the above-mentioned teeth rattle noise.

[0023] When the fluctuation range of the engine speed exceeds the above-mentioned predetermined value or is predicted to exceed it, the controller 10 is provided with a maintenance measure detection unit 10c that detects the maintenance measure executed immediately before that. The maintenance measure is a measure performed to enable stable operation of the engine 1, such as additional supply of new fuel to the fuel tank 3, or replacement or additional supply of lubricating oil for the engine 1 or the transmission 2. That is, if the additionally supplied fuel (for example, gasoline) is not suitable for the engine 1, the combustion becomes unstable and the rotation fluctuation worsens. In addition, if the lubricating oil is not genuine, lubrication failure may occur, the rotation fluctuation may worsen, or the warm-up time may become longer or shorter than the expected predetermined time. The execution of these maintenance measures can be detected based on an increase in the remaining amount detected by the fuel sensor 4 or an increase in the amount of oil detected by the oil sensor 8.

[0024] The controller 10 is provided with a storage unit 10d that can store the contents of the detected maintenance measures and information on when the maintenance measures were performed (time stamp) and output the information to the outside. The information on when the maintenance measures were performed may be a date and time, or a date and time, or a date only, or a mileage recorded by an odometer or the like, as appropriate. The date and time may be obtained from a timer or calendar that is generally provided in a vehicle. The storage unit 10d is configured to output the stored contents to the outside by voice, text, image, or the like periodically or when requested.

[0025] An example of the control according to the present invention executed by the controller 10 is shown in a flow chart in Fig. 4. The routine shown in Fig. 4 is executed repeatedly at predetermined short intervals when the engine 1 is started, or when the ready switch is on in a hybrid vehicle. First, it is determined whether the above-mentioned stable conditions are met (step S1). The stable conditions here are that the warm-up is complete and that the engine is idling. The completion of the warm-up can be determined based on the temperatures detected by the water temperature sensor 5 and oil temperature sensor 9, and the idling state can be determined based on the accelerator opening.

[0026] If the determination result in step S1 is "No", the process returns without carrying out any particular control. Conversely, if the determination result in step S1 is "Yes", the engine speed fluctuation ΔNepre is acquired (step S2). It is determined whether the acquired engine speed fluctuation ΔNepre is equal to or greater than a predetermined value (step S3). The engine speed fluctuation ΔNepre is the difference between the maximum value (maximum value) and the minimum value (minimum value) of the engine speed within a predetermined time, and is synonymous with the fluctuation width of the engine speed, and the predetermined value is synonymous with the range of the fluctuation width of the engine speed. Therefore, if the determination result in step S3 is "No", the fluctuation in the speed of the engine 1 is within an expected range or a reference range, and the engine 1 is operating normally, so the process returns without carrying out any particular control.

[0027] On the other hand, if the determination result in step S3 is "Yes", it is estimated that the fluctuation range of the engine speed has become large or will become large, so the operating point of the engine 1 is changed (step S4). That is, the rattle suppression operation line Li shown in Fig. 2 is selected based on the magnitude of the engine speed fluctuation ΔNepre, and the operating point of the engine 1 is changed to the operating point represented by the intersection of the constant power line Pi and the rattle suppression operation line Li at that time. The operating point is changed by changing the engine torque and engine speed along the constant power line Pi, and setting the engine torque and engine speed at the operating point which is the intersection of the constant power line Pi and the rattle suppression operation line Li.

[0028] Next, it is determined whether the remaining fuel amount has increased by a predetermined amount or more since the previous trip (step S5). In other words, it is determined whether additional fuel was supplied immediately before the determination that the fluctuation in engine speed had worsened. This is a determination as to whether the above-mentioned maintenance measure was performed. If the result of the determination in step S5 is "yes," information on refueling, which is a maintenance measure, and the timing of its execution are stored (step S6). This is to presume that the cause of the fluctuation in engine speed is the refueling that was performed immediately before, so that measures against the cause of the fluctuation can be taken after the fact.

[0029] If the result of the determination in step S5 is "no" or after the control in step S6 is executed, it is determined whether the warm-up time of the engine 1 or the transmission 2 is within a predetermined range (step S7). The predetermined range that is the basis for this determination is, as shown in FIG. 5 as an example, a time width with an upper limit time and a lower limit time that are preset according to the outside air temperature. The warm-up time is the time until the temperature of the engine 1 (the value detected by the water temperature sensor 5) reaches a predetermined temperature after the engine 1 is started, and since the warm-up progresses more easily as the outside air temperature is higher, the upper limit time and the lower limit time that determine this time width are shorter as the outside air temperature is higher. If the warm-up progresses too early or, conversely, is delayed, it is considered that the cause (factor) is the use of lubricating oil other than genuine, so the determination in step S7 is performed.

[0030] If the result of the determination in step S7 is "no", that is, if the warm-up time is outside the predetermined range, the additional supply of lubricant, which is a maintenance measure, and information on the execution time are stored (step S8), and then the process returns. This is to presume that the cause of the fluctuation in the engine speed is the immediately preceding additional supply or replacement of lubricant, and to enable measures to be taken after the fact to address the cause of the fluctuation.

[0031] On the other hand, if the result of the judgment in step S7 is "yes", that is, if the warm-up time is within the specified range and there is no abnormality in this respect, information on the time when this judgment was made and the fact that the cause (factor of deterioration) of the deterioration of the rotation fluctuation is unknown are stored (step S9), and then the program returns.

[0032] The contents stored in steps S6 and S8 described above can be output to the outside as voice, text, or images, so that when the engine speed fluctuation worsens and rattle noise occurs or the possibility of this occurring is estimated, the cause (or factor) of the deterioration can be known by outputting the stored contents to the outside. As a result, according to the above embodiment, not only is rattle noise suppression control executed every time a fluctuation in the engine speed occurs or is estimated, but it is also possible to take measures such as removing the cause of the occurrence to prevent the engine speed fluctuation from worsening again. [Explanation of symbols]

[0033] 1 Engine 2 Transmission 3. Fuel tank 4 Fuel Sensor 5. Water Temperature Sensor 6. Rotational Speed ​​Sensor 7 Oil pan 8 Oil Sensor 9. Oil Temperature Sensor 10 Controller 10a Control condition determination unit 10b Rotational fluctuation detection section 10c Maintenance Measures Detection Section 10d storage section Li Rattle noise suppression operating line Ne Engine RPM OFC Optimal Fuel Economy Line Pi isopower line Te engine torque

Claims

[Claim 1] A control device for a vehicle equipped with an internal combustion engine and a gear-type transmission mechanism that transmits power output by the internal combustion engine, the control device changing an operating point of the internal combustion engine when a fluctuation range of a rotation speed of the internal combustion engine exceeds a predetermined reference range, a controller for monitoring a fluctuation range of a rotation speed of the internal combustion engine, The controller: a rotational fluctuation detection unit that detects when a fluctuation range of the rotational speed of the internal combustion engine exceeds the reference range; a maintenance action detection unit that detects that a maintenance action including the supply of fuel to the internal combustion engine and the supply of lubricating oil to the internal combustion engine or the transmission mechanism has been performed and information on the execution time of the maintenance action; a storage unit that, when the rotational fluctuation detection unit detects that the fluctuation range of the rotational speed of the internal combustion engine has exceeded the reference range, stores the content of the maintenance action performed immediately before the detection and information on the execution time of the maintenance action, and outputs the stored content to an external device. A vehicle control device comprising:

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