JP4895138B2 - Engine starting performance judgment device - Google Patents

Description

    The present invention relates to an engine start performance determination device, and more particularly to an apparatus for measuring a battery output voltage and an engine speed when starting a vehicle engine and determining the engine start performance based on these measurement results.

  In recent years, in vehicles equipped with an engine as an internal combustion engine, for example, when waiting for a signal at an intersection, the number of vehicles that perform so-called idle stop tends to increase when the vehicle is temporarily stopped. In such a case, if the engine cannot be restarted after performing idle stop, a so-called engine stall state occurs, and even if the signal changes, the vehicle cannot be started, causing a traffic jam or the like. Not only that, but also incurs the risk of traffic accidents to the passengers. Therefore, it is required to perform the idling stop described above only when the engine can be restarted reliably later. For this reason, it is necessary to accurately determine the starting performance of the engine.

  2. Description of the Related Art Conventionally, there has been proposed an apparatus that measures battery output voltage and cranking rotation speed when starting a vehicle engine and determines engine start performance based on these measurement results (see, for example, Patent Document 1).

That is, the device described in Patent Document 1 measures the battery output voltage and the cranking rotation speed when starting the engine of the vehicle, and determines the engine starting performance and the battery state based on these measurement results.
JP 2006-240541 A

  In the apparatus described in Patent Document 1, it is not considered at all to determine future engine starting performance in consideration of changes in engine temperature and changes in battery state. However, in an actual vehicle, the engine temperature may change greatly due to the influence of the place where the vehicle is used and the ambient temperature, and the internal state of the battery changes as the vehicle usage period and travel distance increase. There are many things. Therefore, the apparatus described in Patent Document 1 cannot accurately determine the engine start performance in consideration of future engine temperature changes and battery state changes. From this point of view, the development of technology that makes it possible to determine the engine starting performance with high accuracy regardless of the influence of the place of use of the vehicle and the ambient temperature, and even if the vehicle usage period and mileage become long. It is desired.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of determining engine start performance with high accuracy in consideration of changes in engine temperature and battery state.

  Hereinafter, each means suitable for solving the above-described problems will be described with additional effects and the like as necessary.

1. An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
Engine temperature detection means for detecting the temperature of the engine;
Storage means for storing a data set at the time of engine start including the intersection of VN calculated by the intersection calculation means and the engine temperature detected by the engine temperature detection means each time the engine is started;
Based on the engine temperature at the later time detected by the engine temperature detecting means and the data set at the time of starting the engine stored in the storage means at a later time than when the engine was started. Intersection prediction means for predicting the intersection of VN;
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means.

  According to the means 1, it is possible to determine the engine start performance with high accuracy in consideration of future engine temperature change.

2. An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
A power storage device internal state quantity detecting means for detecting an internal state quantity of the power storage device;
A memory for storing a data set at the time of engine start including the intersection of VN calculated by the intersection calculation means and the internal state quantity detected by the power storage device internal state quantity detection means each time the engine is started Means,
Based on the internal state quantity at the later time point detected by the power storage device internal state quantity detection means and the data set at the time of engine startup stored in the storage means at a time point after the engine start time. Intersection prediction means for predicting the intersection of VN at the time of
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means.

  According to the means 2, it is possible to determine the engine start performance with high accuracy in consideration of the change in the internal state quantity of the power storage device in the future.

  3. 3. The engine start performance judging device according to claim 2, wherein the internal state quantity is an internal resistance R or ΔR of the power storage device.

  According to the means 3, it is possible to determine the engine start performance with high accuracy in consideration of the change in the internal resistance R or ΔR of the future power storage device.

  4). The engine start performance determining device according to claim 2, wherein the internal state quantity is an SOC or ΔSOC of the power storage device.

  According to the means 4, it is possible to determine the engine start performance with high accuracy in consideration of the change in the SOC or ΔSOC of the future power storage device.

  5. 3. The engine start performance judging device according to claim 2, wherein the internal state quantity is a remaining capacity Ah or ΔAh of the power storage device.

  According to the means 5, it is possible to determine the engine start performance with high accuracy in consideration of a change in the remaining capacity Ah or ΔAh of the future power storage device.

  6). The intersection predicting means uses the predetermined number of data sets when the storage means stores the data set at the time of starting the engine at least twice, and uses the predetermined number of data sets to determine the intersection of VN at the later time point. The engine start performance judging device according to any one of means 1 to 5, wherein

  According to the means 6, since the engine starting performance is determined based on a data set (actually measured value) for a predetermined number of times at least twice before the later time point in the engine of the vehicle, This self-learning makes it possible to determine the engine starting performance corresponding to the change over time in the engine temperature or the electrical characteristics of the power storage device. In addition, since the intersection of VN at a later time is predicted from the data set (actual measurement value) for at least two times, it is possible to ensure the accuracy of the intersection prediction.

  7). The engine start performance judging device according to any one of means 1 to 6, wherein only the data set obtained during a predetermined period before the later time point is used as the data set at the time of engine start.

  Here, the predetermined period before the later time point refers to a period in which the engine or the power storage device has not deteriorated over time. Since both the engine and the power storage device deteriorate over time, a reliable data set at the time of starting the engine can be acquired before such deterioration over time occurs, so the predetermined period may be longer. After aged deterioration, a period having the same degree as the degree of aging deterioration at that time can be set as the predetermined period.

  According to the means 7, since the engine starting performance is determined based on a data set (actually measured value) within a predetermined period before the later time point in the engine of the vehicle, the engine temperature or the electrical characteristics of the power storage device change over time. The engine starting performance corresponding to the above can be determined.

  8). The engine speed (N) is obtained by detecting a change in the output voltage (V) of the power storage device at the time of starting the engine and calculating the period of the change into a predetermined calculation formula. The engine starting performance determination apparatus in any one of thru | or 7.

  According to the means 8, since the engine speed (N) can be calculated by detecting the fluctuation of the output voltage (V) of the battery being started, V and N are stored in calculating the intersection of V-N. It can be determined from the output voltage of the device. Therefore, it is possible to realize an engine start performance determination device having a simpler configuration.

9. An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
Engine temperature detection means for detecting the temperature of the engine;
A power storage device internal state quantity detecting means for detecting an internal state quantity of the power storage device;
Each time the engine is started, the VN intersection calculated by the intersection calculation unit, the engine temperature detected by the engine temperature detection unit, and the internal state detected by the power storage device internal state amount detection unit Storage means for storing a data set at the time of engine start including a quantity;
VN map construction means for constructing a VN map for each engine temperature and power storage device internal state quantity based on the stored data set, and storing it in the storage means;
The engine temperature at the later time point detected by the engine temperature detecting means at the time point after the engine start, the internal state quantity at the later time point detected by the power storage device internal state quantity detecting means, and the Intersection prediction means for predicting the intersection of VN at the later time point based on the VN map stored in the storage means;
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means.

  According to the means 9, since both the engine temperature change and the internal state change of the battery are taken into account for determination, the engine start performance can be determined with higher accuracy.

  Further, since the intersection of VN at a later time is predicted based on the VN map constructed for each engine temperature and power storage device internal state quantity, the engine start performance can be determined with higher accuracy.

[1. Engine start performance judgment factor]
First, the inventors analyzed what factors are considered when it is determined that the engine starting performance is poor, that is, when the engine cannot be started. FIG. 1 is a graph showing a relationship (VN characteristic) between a voltage [Vecu] applied to an ECU / relay (see FIG. 5) described later in a vehicle and an engine speed n. In the figure, symbol Vrno represents a voltage at which the relay of the power line to the starter (starting motor) is not turned off, and symbol Venr represents a voltage at which the ignition ECU (ignition unit in the engine ECU [see FIG. 5]) is not reset. ing. The symbol nIa is the engine speed at which the engine can be ignited. That is, in a vehicle, when the capacity of a power storage device (battery), which will be described later, decreases and the output voltage value becomes a predetermined threshold value or less, the ignition ECU (ignition unit in the engine ECU) is reset to ignite the engine. become unable. In addition, when the capacity of the power storage device (battery) is further reduced and the output voltage value falls below another predetermined threshold value, the power line connecting the power storage device and a load including a starter (starting motor) or the like By turning off the provided relay, the power storage device is disconnected from the load to prevent further discharge and prevent deterioration. When the voltage [Vecu] applied to the ECU / relay on the vertical axis of the graph shown in FIG. 1 falls below the other predetermined threshold, the relay connecting the power storage device and the starter (starting motor) is turned off. Therefore, even if the ignition key is turned, the starter (starting motor) is not started and the engine cannot be started. When starting the engine, the rotation of the starter motor (starter) is transmitted to the crankshaft to give the crankshaft initial rotation, and the engine is ignited by the ignition device during the initial rotation of the crankshaft. There is a number of revolutions that can be ignited, and the engine cannot be started if the number falls below this number.

As a result of the analysis by the present inventors, it was found that in the actual vehicle, the starting performance is poor when one of the following conditions is satisfied in FIG. That is,
(1) The predicted voltage Vp1 when the voltage drop due to the inrush current of the starter (starting motor) is maximum at the rotation speed n = 0 obtained from the rotation speed-one voltage relational expression (VN characteristic) is the relay described above. It is below the voltage Vrno that does not turn off.
(2) The rotational speed n obtained from the rotational speed-one voltage relational expression (VN characteristic) = the rotational speed nIa that can be ignited, and the predicted voltage Vp2 due to the cranking current is lower than the above-described voltage Venr that does not reset the ECU. .
(3) The predicted rotation speed Vp3 of the starter (starting motor) at a voltage that becomes the ECU reset obtained from the rotation speed-one voltage relational expression (VN characteristic) is lower than the ignition speed nIa.

  Accordingly, it has been clarified that the quality determination of the engine starting performance can be achieved by having all or one or more of the determination conditions (1), (2), and (3).

[2. Verification by experiment]
The principle of engine start performance determination in the present invention is largely related to the above-described VN characteristic at the time of engine start. Without taking into account changes in the future engine temperature or changes in the state of the power storage device (battery), the present inventors can start the engine at a certain point in the future with high accuracy from the VN characteristic data at the time of past engine startup. We gained the basic recognition that performance cannot be judged. Therefore, an experiment was conducted to examine the relationship between the engine temperature change and the battery state change and the VN characteristics described above. FIG. 2A is a graph showing conditions and results of an experiment conducted on the relationship between engine temperature change and the VN characteristic, and FIG. 2B is a graph showing battery state change and the VN characteristic. It is a graph which shows the conditions and the result of the experiment conducted about the relationship.

  First, in the experiment shown in FIG. 2A, VN characteristics (intersections of VN) when the engine temperature changes (decreases) to high temperature, 0 ° C., low temperature 1 and low temperature 2 are calculated, and from these, The VN characteristic (VN intersection) when the engine temperature changed (decreased) to an extremely low temperature was extrapolated. In the figure, the threshold value of the voltage at which the engine can be started and the threshold value of the engine speed are indicated by a thick line drawn perpendicularly to the vertical axis and a thick line drawn perpendicularly to the horizontal axis, respectively. As shown in FIG. 2A, it was found that both V and N at the time of start-up decrease as the engine temperature decreases. In the example shown in FIG. 2 (a), while the engine temperature is high, 0 ° C., low temperature 1, and low temperature 2, both V and N at the start time exceed the threshold at which the engine can be started. It has been found that the engine starting performance can be determined to be good. However, when the engine temperature is changed (decreased) to an extremely low temperature, V and N at the time of start-up predicted to be extrapolated are above the threshold at which the engine can be started, but N can start the engine. It has been found that the engine speed can be determined to be poor because the engine speed is below the threshold value, i.e., the startable engine speed is not obtained. As described above, unless the temperature change of the future engine is taken into consideration, it is impossible to determine (predict the future) the engine starting performance at a future time point with high accuracy.

  Next, in the experiment shown in FIG. 2B, as the internal state quantity of the battery, the internal resistance R of the battery and the charge rate SOC (State Of Charge) are low until the internal resistance is low, and the SOC is high. VN characteristics (VN intersection) when changing to 7 levels until low, VN characteristics (VN) when the internal resistance R of the battery changes to a higher amount are calculated from them. Extrapolated). Also in this figure, the threshold value of the voltage at which the engine can be started and the threshold value of the rotational speed are indicated by a thick line drawn perpendicularly to the vertical axis and a thick line drawn perpendicularly to the horizontal axis, respectively. As shown in FIG. 2B, it was found that both V and N at the time of start-up decrease as the internal resistance R of the battery increases and the SOC decreases. In the example shown in FIG. 2B, when the internal resistance R and SOC of the battery change in seven stages as described above, both the V and N at the time of start exceed the threshold at which the engine can be started. Therefore, it has been found that the engine starting performance can be determined to be good. And, when the internal resistance R of the battery changes to a higher amount, the V and N values at the time of start that are extrapolated are slightly above the thresholds at which both the V and N can start the engine. It has been found that a high voltage and speed can be obtained, and therefore it can be determined that the engine starting performance is good. As described above, unless the change in the internal state of the battery in the future is taken into consideration, the engine start performance at a future time cannot be determined (predicted in the future) with high accuracy.

  Furthermore, the present inventors conducted an experiment to compare the VN characteristics in the same vehicle type. In other words, as shown in FIG. For 1 to 14, as shown in FIG. 3B, the engine speed [rpm] when the output voltage [V] of the battery was changed was measured and plotted. As is apparent from FIG. 3, it was found that the VN characteristics are different for each vehicle. Therefore, even if the data relating to the VN characteristics is data obtained for the vehicle type, the engine start performance cannot be determined (predicted in the future) with high accuracy using the data stored in advance.

[3. Characteristic]
As described above, also from the experimental results shown in FIG. 2 and FIG. 3, the present inventors consider the engine temperature change or the internal state change of the battery in order to determine the engine start performance with high accuracy (future prediction). It is necessary to determine (predict) the engine start performance using the data regarding the VN characteristic constructed based on the value actually measured in the vehicle, not the data stored in advance. It came to obtain the knowledge that. The characteristics of the engine start performance determination according to the present invention will be described with reference to FIG. FIG. 4 is a diagram for explaining a method for determining engine start performance based on VN characteristic data constructed from actual measurement values in the vehicle. In the graph of FIG. 4, the horizontal axis represents the rotation speed [rpm], and the vertical axis represents the battery output voltage [V]. In FIG. 4, nth represents a startable rotation speed threshold value, and Vth represents a startable voltage threshold value.

  In the figure, an arrow connecting the current value Cp and the future predicted value Cf indicates the prediction when the engine temperature changes. That is, the graph of FIG. 4 is obtained by interpolating and calculating the future VN intersection based on (1) the VN intersection at the time of engine startup and (2) the engine temperature data set obtained at each engine startup. It shows that extrapolation is predicted.

  As shown in the figure, the future predicted value Cf can be obtained by taking into account the influence of the engine temperature change based on the current value Cp, that is, the data on the intersection of VN actually measured this time. As shown in the figure, when the predicted future value Cf exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it is determined that the engine start performance at the future time point is good. it can. On the contrary, unlike the case shown in the figure, if the future predicted value Cf is lower than the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it is determined that the engine start performance at the future time point is poor. be able to.

  The case where the engine start performance is determined in consideration of the temperature change of the engine has been described above. However, the engine start performance may be determined in consideration of the change in the internal state of the battery. In this case, an arrow connecting the current value Cp and the future predicted value Cf in FIG. 4 indicates the prediction when the battery state changes. The graph of FIG. 4 interpolates the future VN intersection based on (1) the VN intersection at the time of engine startup and (3) the battery state quantity data set obtained at each engine startup. -Indicates extrapolation prediction. Then, as in the case of taking into account the temperature change of the engine, the future predicted value Cf is obtained in consideration of the influence of the battery state change based on the current value Cp, that is, the data on the intersection of VN actually measured this time. Can do. As shown in the figure, when the predicted future value Cf exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it is determined that the engine start performance at the future time point is good. On the contrary, unlike the case shown in the figure, if the future predicted value Cf is lower than the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it means that the engine start performance at the future time point is poor. The determination can be made in the same manner as when the temperature change of the engine is taken into account.

  By using such an engine start performance determination method of the present invention, that is, a determination method of engine start performance based on VN characteristic data constructed by actual measurement values in the vehicle, as a first effect, engine temperature change, Alternatively, it is possible to determine the future engine starting performance in consideration of the battery state change. Further, as a second effect, the VN characteristic data is constructed (self-learning) based on the actual measurement value in the vehicle, thereby responding to changes in the characteristics of electric systems such as an engine starter motor and a battery in the vehicle over time. The engine start performance can be determined.

[4. Constitution]
DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying an engine start performance determination device of the present invention will be specifically described with reference to the drawings.

  FIG. 5 shows a configuration of main parts related to the engine and the power storage device (battery) in a vehicle to which the engine start performance determination device according to the present embodiment is applied. In FIG. 5, an engine 10 as an internal combustion engine is a port injection type gasoline engine. The engine 10 is a power generation device for a vehicle (not shown), and its output shaft (crankshaft 12) is mechanically connected to drive wheels (not shown) of the vehicle. On the other hand, the power generation apparatus 20 includes an alternator 22 as a generator and a regulator 24 as a control circuit that controls the output of the alternator 22. Here, the rotor of the alternator 22 is mechanically connected to the crankshaft 12 of the engine 10 and is rotated by the rotational force of the crankshaft 12.

  A battery 30 as a lead storage battery is connected to the battery terminal TB of the power generation device 20. An electric load 44 is connected to the battery 30 via the switch 42 in parallel. Furthermore, a starter motor (starter) 40 that applies initial rotation to the crankshaft 12 of the engine 10 is connected to the battery 30 as an electrical load. On the other hand, the power supply line between the battery terminal TB and the battery 30 and the ignition terminal TIG of the power generation apparatus 20 are connected via an ignition switch 46.

  The engine ECU 50 and the battery ECU 60 as the electric loads of the battery 30 are mainly configured by a microcomputer, and also include a CPU as a central processing unit, a ROM, a RAM as a storage device, and the like. Here, the battery ECU 60 monitors the internal state of the battery 30 based on the detection value of the battery temperature sensor 54 that detects the temperature of the battery 30 and the detection value of the voltage sensor 56 that detects the output voltage of the battery 30. When the capacity of the battery 30 is reduced and the output voltage value of the battery 30 detected by the voltage sensor 56 becomes a predetermined threshold value or less, the battery 30 is connected to a load including a starter motor (starter) 40 and the like. The relay R provided in the power line to be controlled is turned off to disconnect the battery 30 from the load and eliminate further discharge to prevent deterioration.

  On the other hand, the engine ECU 50 controls the engine 10 and the power generation device 20. The engine ECU 50 monitors the temperature change of the engine 10 based on the detection value of the engine temperature sensor 14 that detects the temperature of the engine 10. The engine ECU 50 determines the voltage (power generation) applied to the battery terminal TB of the power generation device 20 based on information (for example, SOC: State of charge) indicating the internal state (battery state) of the battery 30 output from the battery ECU 60. The output voltage of the device 20 is controlled. Specifically, the engine ECU 50 outputs a command value (command voltage) of the output voltage of the power generation device 20 to the command terminal TR of the power generation device 20. Thereby, the regulator 24 controls the output voltage of the power generator 20 to the command voltage. Further, the engine ECU 50 takes in a power generation state signal indicating the power generation capability of the power generation device 20 via the monitor terminal TF of the power generation device 20. Here, the power generation capacity is quantified by the ON / OFF time ratio of the switching element in the regulator 24 (specifically, the ratio of the ON time to the ON / OFF cycle: Duty).

  Further, the engine ECU 50 automatically stops the engine 10 from the idle stop control (automatic stop process) that stops the engine 10 idle rotation speed control and automatically stops the engine 10 when the vehicle is stopped. An automatic start process is performed to start automatically. Here, the automatic start process is executed by performing combustion control such as starting the starter 40 to apply the initial rotation to the crankshaft 12 of the engine 10 and then igniting the ignition device 41 described above. Note that such control as ignition by the ignition device 41 is performed by an ignition unit (not shown) in the engine ECU (50) described with reference to FIG.

  Now, in the present embodiment, in the configuration shown in FIG. 5, the engine ECU 50 and the battery ECU 60 include an engine start performance determination unit 70 inside. The engine start performance determination device according to the present embodiment is a device that determines the start performance of the engine 10 in the vehicle in which the engine 10 and the battery 30 as a power storage device are mounted. The engine start performance determination device mainly includes an engine ECU 50 and a battery ECU 60. The engine starting performance determination unit 70, the engine temperature sensor 14 as engine temperature detection means for detecting the temperature of the engine 10, and a voltage sensor 56 for detecting the output voltage of the battery 30 are configured. The engine speed (N) can be obtained by a known method that is obtained by detecting the cranking speed.

The engine start performance determination unit 70 in the engine ECU 50 and the battery ECU 60 is a characteristic part of the present embodiment. As an intersection calculation unit, the output voltage (V) of the battery 30 at the start and the engine every time the engine 10 is started. of 10 rpm to the intersection of the coordinates (N) (the intersection of the _{V-N) C V-N} ( see FIG. 1, 2, 4) is calculated. Further, the calculated VN intersection data and the engine temperature data detected by the engine temperature sensor 14 are used as a data set at the time of engine start, and an EEPROM (not shown) in the engine start performance determination unit 70 as a storage means To remember. Now, the engine start performance determination unit 70 serves as an intersection prediction means at a time after the engine start, and the temperature of the engine 10 detected by the engine temperature sensor 14 and the stored past engine start data. Based on the set, the intersection of VN at the subsequent time point is predicted to be interpolated / extrapolated. Then, based on the predicted intersection of V-N (corresponding to the future predicted value Cf shown in FIG. 4), the starting performance of the engine 10 at the subsequent time is determined as a determining means. The determination is made based on whether the predicted intersection of VN (corresponding to the future predicted value Cf) exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth shown in FIG. When the predicted intersection of V-N (corresponding to the future predicted value Cf) exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth, the engine start performance at the subsequent time point is good. Is determined. On the other hand, if the predicted intersection of VN (corresponding to the future predicted value Cf) falls below either the startable rotation speed threshold value nth or the startable voltage threshold value Vth, the engine at the subsequent time point It is determined that the starting performance is poor.

  Thus, according to the engine start performance determination device of the present embodiment, the start performance of the engine 10 can be determined with high accuracy in consideration of the future temperature change of the engine 10.

  In the example described above, the case where the engine start performance is determined in consideration of the temperature change of the engine has been described. However, the engine start performance may be determined in consideration of the internal state change of the battery. That is, in the present embodiment, the engine start performance determination unit 70 described above further serves as an intersection calculation means every time the engine 10 is started, and the output voltage (V) of the battery 30 at the time of start-up and the rotation speed ( The intersection point (V-N intersection point) on the coordinates of N) is calculated. Further, the internal state quantity of the battery 30 as the power storage device is detected as a power storage device internal state quantity detection means. Further, the calculated intersection data of VN and the detected internal state quantity data of the battery 30 are stored as a data set at the time of engine start in an EEPROM (not shown) or the like in the engine start performance determination unit 70 as storage means. To do. Now, the engine start performance determination unit 70, as the intersection prediction means, at a time point after the engine start time, the internal state quantity of the battery 30 at the later time point detected as the power storage device internal state quantity detection means and the stored past Based on the data set at the time of engine start, the intersection of VN at the subsequent time point is predicted to be interpolated / extrapolated. Then, based on the predicted intersection of V-N (corresponding to the future predicted value Cf shown in FIG. 4), the starting performance of the engine 10 at the subsequent time is determined as a determining means. The determination is made based on whether the predicted intersection of VN (corresponding to the future predicted value Cf) exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth shown in FIG. When the predicted intersection of V-N (corresponding to the future predicted value Cf) exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth, the engine start performance at the subsequent time point is good. Is determined. On the other hand, if the predicted intersection of VN (corresponding to the future predicted value Cf) falls below either the startable rotation speed threshold value nth or the startable voltage threshold value Vth, the engine at the subsequent time point It is determined that the starting performance is poor.

  As described above, according to the engine start performance determination device of the present embodiment, the start performance of the engine 10 can be determined with high accuracy in consideration of the future change in the internal state quantity of the battery 30.

  In the above example, the engine start performance determination unit 70 as the power storage device internal quantity state detection means detects the internal resistance R or ΔR of the battery 30 as the internal state quantity of the battery 30. By detecting the internal resistance R or ΔR of the battery 30, it is possible to determine the starting performance of the engine 10 with high accuracy in consideration of a future change in the internal resistance R of the battery 30. Further, the SOC or ΔSOC of the battery 30 or the remaining capacity Ah or ΔAh of the battery 30 may be detected. By detecting the SOC or ΔSOC of the battery 30, it is possible to determine the starting performance of the engine 10 with high accuracy in consideration of the future change in the SOC of the battery 30. Further, by detecting the remaining capacity Ah or ΔAh of the battery 30, it is possible to determine the starting performance of the engine 10 with high accuracy in consideration of a future change in the remaining capacity Ah of the battery 30.

  The internal state quantity of the battery 30 described above is not one of the internal resistance R or ΔR, the SOC or ΔSOC, and the remaining capacity Ah or ΔAh, but two or more of these internal state quantities. The state quantity may be detected. Thereby, the change in the internal state of the battery 30 is grasped from various directions, and the start performance of the engine 10 can be determined with higher accuracy by taking these plural internal state changes into consideration.

  Furthermore, in the present embodiment, the engine start performance determination unit 70 as the intersection prediction unit stores at least two or more times when the data set at the time of engine start is stored as the storage unit at least twice. It is desirable to interpolate and extrapolate VN intersections at a later time using a data set. In this desirable mode, the engine start performance determination unit 70 described above determines the start performance of the engine 10 based on data (actually measured values) at least twice before the later time point in the engine of the vehicle. The self-learning inherent to the engine 10 or the battery 30 can determine the starting performance of the engine 10 corresponding to the temporal change of the engine temperature or the electrical characteristics of the battery 30. In order to ensure the accuracy of intersection prediction, the predetermined number of times is preferably about 10 times, for example.

  Further, it is preferable to use only the data set obtained at the time of starting the engine within a predetermined period before a later time point. Here, the predetermined period before the later time point refers to a period in which the engine or the power storage device has not deteriorated over time. Since both the engine and the power storage device deteriorate over time, a reliable data set at the time of starting the engine can be acquired before such deterioration over time occurs, so the predetermined period may be longer. After aged deterioration, a period having the same degree as the degree of aging deterioration at that time can be set as the predetermined period.

  As a result, the starting performance of the engine 10 is determined based on a data set (actually measured value) within a predetermined period before the later time point in the engine 10 of the vehicle, so that the temperature of the engine 10 or the electrical characteristics of the battery 30 over time is determined. The starting performance of the engine 10 corresponding to the change can be determined.

[5. Operation]
Next, start performance determination data acquisition processing of the engine start performance determination device according to the present embodiment will be described. FIG. 6 is a flowchart of start performance determination data acquisition processing in the engine start performance determination unit 70. This process is realized by the CPU in the engine start performance determination unit 70 executing a program stored in the ROM while using the RAM area as a variable storage area. First, when the start performance determination data acquisition process is started (step S1), it is determined whether or not the engine has been started (step S2). If the engine is started (yes in step S2), the number of engine start times Is counted (step S3). That is, the engine start this time is counted, and one is added to the number of start up so far. Next, processing for detecting and storing the data sets in steps S4 to S6 is performed. That is, the engine speed N during cranking is detected and stored (step S4), the battery output voltage V during cranking is detected and stored (step S5), and the engine temperature T is detected and stored (step S6). . These parameters are stored in the variable storage area of the RAM in the engine start performance determination unit 70 described above. Then, it is determined whether or not the above data set has been stored a predetermined number of times, and in particular, it is determined whether or not the number of times is greater than a predetermined value, for example, 10 (step S7). When the data set is stored a plurality of times larger than the specified value (yes in step S7), it is determined whether or not the data set acquisition flag is OFF (step S8), and the data set acquisition flag is turned OFF. If yes (Yes in step S8), the data set is updated, that is, the oldest data and the latest data are exchanged (step S9), and the process returns to the start. If the data set acquisition flag is not OFF (no in step S8), the data set acquisition is completed, the data set acquisition flag is turned ON (step S10), and the process returns to the start. As described above, according to the present embodiment, for example, the data set at the time of starting the engine more than the specified number of times of 10 is stored, and the accumulated data set is updated to the latest one. Therefore, it is possible to determine the starting performance with high accuracy based on the latest data.

  Further, in the present embodiment, the engine ECU 50 controls the idle stop when the engine start performance determination unit 70 determines the engine start performance. FIG. 7 is a flowchart showing an idle stop control process by the engine ECU 50 including the engine start performance determination unit 70. This process is realized by the CPU in the engine ECU 50 executing a program stored in the ROM while using the RAM area as a variable storage area. First, when the idle stop control process is started (step S1), it is determined whether or not the vehicle has stopped (step S2). If the vehicle has not stopped (no in step S2), the idle stop is determined. Since there is no need for this, the process returns to the start.

  When the vehicle stops (yes in step S2), it is determined whether or not the data set acquisition flag is ON (step S3). That is, in the process described in FIG. 6, it is for determining whether or not the engine can be restarted only when the latest data for the specified number of times has been acquired. When the data set acquisition flag is ON (yes in step S3), in order to determine whether the engine can be restarted, the intersection of VN is predicted to be interpolated / extrapolated (step S4). Then, based on the result of the interpolated / extrapolated prediction, it is determined whether or not the engine can be restarted after idling stop (step S5). If it is determined that the engine can be restarted (yes in step S5), idle stop is performed, that is, the engine is stopped (step S6), and the process returns to the start. On the contrary, when it is determined that the engine cannot be restarted (no in step S5), the idle stop is not performed, that is, the engine is not stopped (step S7), and the process returns to the start. As described above, according to the present embodiment, in the process described in FIG. 6, it is determined whether or not the engine can be restarted only when the latest data for the specified number of times has been acquired. In consideration of the engine temperature, the V-N intersection point is interpolated and extrapolated, and based on the result, it is determined whether the engine can be restarted after idling stop. It is possible to determine the starting performance with high accuracy. And since it is determined whether idle stop is possible based on this highly accurate determination (preliminary prediction), it is possible to perform idle stop only when it can be reliably restarted. Therefore, it is possible to effectively prevent a situation where the engine cannot be restarted after idling stop and a so-called engine stall state occurs. As a result, it is possible to reliably start the vehicle even when waiting for a traffic signal at an intersection, etc., leading to prevention of traffic jams and dangers of passenger traffic accidents.

[6. Modified example]
In the above-described example, the engine speed (N) data is obtained by a known method for detecting and detecting the cranking speed. However, the engine speed (N) is calculated based on the battery output voltage (V). It is also possible to calculate from

  In such a configuration, it is not necessary to detect the cranking rotation speed. Accordingly, since only the voltage sensor 56 that detects the output voltage of the battery 30 has to be used, the engine start performance determination device of the present embodiment can be configured more simply.

  Hereinafter, a method for calculating the engine speed (N) by detecting the fluctuation of the output voltage (V) of the battery during the start will be described with reference to FIG. FIG. 8 shows a voltage waveform of the output voltage (V) of the battery when the engine is started. That is, in the figure, the voltage waveform of the output voltage (V) of the battery when the starter motor (starter) is started and the crankshaft to which the rotation is transmitted starts rotating (cranking) when the engine is started. It is shown. During cranking at the time of engine start, the motor torque required for the starter motor (starter) fluctuates periodically due to the difference in engine friction between the upper fulcrum and lower fulcrum of the cylinder. The voltage (V) also varies periodically.

  Here, (a) the time (?) From the timing when the voltage fluctuation changes from rising to falling to (i) the timing when the next voltage fluctuation changes from rising to falling is measured. Similarly, the time from (i) to (u) is measured as (ki), and the time from (u) to (e) is measured as (ku). The fluctuation time (）) to (く) of the output voltage (V) of the battery indicates the change time of the position of the top dead center and the bottom dead center of the cylinder as described above. Therefore, the engine speed (N) can be calculated by performing a predetermined calculation according to the number of cylinders of the engine and the cylinder arrangement of each cylinder.

  For example, in the case of a V8 engine, the number of cylinder friction changes per one rotation of the engine crank is 4, that is, the time of fluctuation of the battery output voltage (V) accompanying the movement from the top dead center to the top dead center. However, when the period is measured as 120 ms, the engine speed (N) (rpm) is expressed by 60 (seconds) / (period (seconds) * number of cylinder friction changes per engine crank rotation). Therefore, the engine speed (N) (rpm) is 125 (rpm) from the following formula 1.

[Formula 1] N = 60 / (120/1000 * 4) = 125 (rpm)
In this way, it is possible to calculate the engine speed (N) by detecting the fluctuation of the output voltage (V) of the battery during startup. As described above, according to this modification, V and N are obtained from the output voltage of the power storage device when calculating the intersection of V-N when the engine is started. Specifically, the output voltage of the battery 30 It is possible to calculate using only the voltage sensor 56 for detecting. Therefore, it is possible to configure the engine start performance determination device of the present embodiment more easily and at low cost.

  As described above, in the present modification, the engine speed (N) is detected by detecting a change in the output voltage (V) of the power storage device at the time of starting the engine, and the period of the change is determined by the predetermined calculation formula described above. So that it can be calculated. As a result, the engine speed (N) can be calculated by detecting a change in the output voltage (V) of the battery during start-up, so that V and N are outputs of the power storage device when calculating the intersection of VN. It can be obtained from the voltage. Therefore, it is possible to realize an engine start performance determination device having a simpler configuration. Specifically, in FIG. 5, the voltage sensor 56 that detects the output voltage of the battery 30 may be used to detect a change in the output voltage (V) of the battery 30 that is being started. An engine start performance determination device can be configured.

[7. Other Embodiments]
In the above-described embodiment, the example in which the engine start performance is determined in consideration of either the engine temperature change or the battery internal state change has been described. However, both the engine temperature change and the battery internal state change are considered. It is also possible to determine the engine start performance. Such a feature of another embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram similar to FIG. 4 described above, and is a conceptual diagram showing the principle of determination of engine start performance in another embodiment of the present invention.

  That is, in order to determine the engine start performance with higher accuracy (predicting the future), it is desirable to determine the engine start performance in consideration of both the engine temperature change and the battery internal state change. Also in this case, it is a matter of course that the engine start performance is determined (predicted) using data relating to the VN characteristics constructed based on values actually measured in the vehicle rather than data stored in advance. The characteristics of the engine start performance determination will be described. FIG. 9 is a diagram for explaining a method for determining engine start performance based on VN characteristic data constructed from actual measurement values in the vehicle. Similar to FIG. 4 described above, in the graph of FIG. 9, the horizontal axis indicates the number of revolutions [rpm], and the vertical axis indicates the output voltage [V] of the battery. Further, nth represents a startable rotation speed threshold value, and Vth represents a startable voltage threshold value.

  In FIG. 9, the alternate long and short dash line indicates the prediction when the engine temperature changes, and the dotted line indicates the prediction when the battery state changes. That is, FIG. 9 shows that a map is constructed based on the data set of (1) V-N intersection at engine start, (2) engine temperature, and (3) battery state quantity acquired at each engine start. Show. Then, as shown in the figure, based on the current value Cp, that is, the data on the intersection of VN actually measured this time, the future predicted value Cf is calculated by considering the influence of the engine temperature change and the influence of the battery state change. Obtainable. As shown in the figure, when the predicted future value Cf exceeds the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it is determined that the engine start performance at the future time point is good. it can. On the contrary, unlike the case shown in the figure, if the future predicted value Cf is lower than the startable rotation speed threshold value nth and the startable voltage threshold value Vth, it is determined that the engine start performance at the future time point is poor. be able to.

  Such determination of engine start performance in another embodiment of the present invention, that is, determination of engine start performance by referring to a map based on VN characteristic data constructed from actual measurement values in the vehicle, As an effect of 1, it is possible to determine the future engine starting performance in consideration of both the engine temperature change and the battery state change. Further, as a second effect, by building (self-learning) a map based on the VN characteristic data based on the actual measurement value in the vehicle, the characteristics of the electric system such as the engine start motor and the battery in the vehicle over time. It is possible to determine the engine start performance corresponding to the change. In another embodiment of the present invention, engine start performance determination unit 70 in engine ECU 50 and battery ECU 60 determines engine start performance in a vehicle in which engine 10 and power storage device 30 are mounted. Each time the engine 10 is started, an intersection (V-N intersection) on the coordinates of the output voltage (V) of the power storage device 30 and the engine speed (N) when the engine 10 is started is calculated. The intersection calculation means, the engine temperature detection means for detecting the temperature of the engine 10, the power storage device internal state quantity detection means for detecting the internal state quantity of the power storage device 30, and the above calculation calculated by the intersection calculation means each time the engine 10 is started The intersection of VN, the engine temperature detected by the engine temperature detection means, and the internal state detected by the power storage device internal state quantity detection means Storage means for storing a data set at the time of starting the engine including the amount, and a VN map for each engine temperature and power storage device internal state quantity based on the stored data set and stored in the storage means The map construction means, the temperature of the engine 10 at the later time point detected by the engine temperature detection means at the time point after the engine start, and the internal state quantity at the later time point detected by the power storage device internal state quantity detection means And based on the VN map stored in the storage means, the intersection prediction means for predicting the intersection of VN at the subsequent time point, and the intersection of the VN predicted by the intersection prediction means, The engine 10 is configured to function as a determination unit that determines the starting performance of the engine 10 at a later time. According to the present embodiment, the determination is made by taking into account both the temperature change of the engine and the internal state change of the battery, and therefore the engine start performance can be determined with higher accuracy. Further, since the intersection of VN at a later time is predicted based on the VN map constructed for each engine temperature and power storage device internal state quantity, the engine start performance can be determined with higher accuracy.

  According to the present embodiment, it is necessary to store and process a relatively large amount of data in order to construct a map, but there is also an advantage that the engine start performance can be determined with higher accuracy.

  Actually, other factors that affect engine starting performance include friction inside the engine. Therefore, it is possible to consider the internal friction of the engine. However, the engine internal friction is a factor that changes over a much longer time than the engine temperature and battery condition, so predicting (estimating) the engine start performance in the near future, such as when applied to the eco-run control mentioned above. If so, it is understood that it is sufficient to consider both engine temperature change and battery state change.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible in the range which does not deviate from the main point of this invention. For example, in the above-described embodiment, an example is shown in which the engine start performance is determined to perform idling stop control, so-called eco-run, but the engine start performance determination is also performed for other control purposes. Of course you can.

  The present invention can be applied to an apparatus that measures a battery output voltage and an engine speed at the time of engine start of a vehicle and determines engine start performance based on these measurement results.

It is a graph which shows the relationship (VN characteristic) between the voltage [Vecu] applied to ECU and a relay, and the engine speed n. (A) is a graph which shows the relationship between engine temperature change and a VN characteristic, (b) is a graph which shows the relationship between a battery state change and a VN characteristic. It is a figure which shows the experimental result which compared the VN characteristic in the same vehicle model, (a) is vehicle No. of the test vehicle (same vehicle type) used for experiment. And (b) is a graph obtained by measuring and plotting the engine speed [rpm] when the voltage [V] is changed. It is a figure for demonstrating the characteristic of the engine starting performance determination method in the engine starting performance determination apparatus which concerns on embodiment of this invention. It is a figure which shows the structure of the engine starting performance determination apparatus which concerns on embodiment of this invention. It is a flowchart which shows the engine starting performance determination data acquisition process which the engine starting performance determination part in the engine starting performance determination apparatus which concerns on embodiment of this invention performs. It is a flowchart which shows the idle stop control process which engine ECU containing the engine starting performance determination part in the engine starting performance determination apparatus which concerns on embodiment of this invention performs. It is a figure for demonstrating the method to detect an engine speed from the voltage fluctuation during the start in the engine starting performance determination apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the characteristic of the engine starting performance determination method in the engine starting performance determination apparatus which concerns on other embodiment of this invention.

Explanation of symbols

10 engine, 30 battery, 50 engine ECU,
60 battery ECU, 70 engine starting performance determination unit, 14 engine temperature sensor,
56 voltage sensor, N engine speed, V battery output voltage,
C Intersection on _V-N coordinates (intersection of V-N), Cp current value, Cf future prediction value

Claims (9)

An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
Engine temperature detection means for detecting the temperature of the engine;
Storage means for storing a data set at the time of engine start including the intersection of VN calculated by the intersection calculation means and the engine temperature detected by the engine temperature detection means each time the engine is started;
Based on the engine temperature at the later time detected by the engine temperature detecting means and the data set at the time of starting the engine stored in the storage means at a later time than when the engine was started. Intersection prediction means for predicting the intersection of VN;
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means. An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
A power storage device internal state quantity detecting means for detecting an internal state quantity of the power storage device;
A memory for storing a data set at the time of engine start including the intersection of VN calculated by the intersection calculation means and the internal state quantity detected by the power storage device internal state quantity detection means each time the engine is started Means,
Based on the internal state quantity at the later time point detected by the power storage device internal state quantity detection means and the data set at the time of engine startup stored in the storage means at a time point after the engine start time. Intersection prediction means for predicting the intersection of VN at the time of
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means.   The engine start performance determination device according to claim 2, wherein the internal state quantity is an internal resistance R or ΔR of the power storage device.   The engine start performance determination device according to claim 2, wherein the internal state quantity is an SOC or ΔSOC of the power storage device.   The engine start performance determination device according to claim 2, wherein the internal state quantity is a remaining capacity Ah or ΔAh of the power storage device.   The intersection predicting means uses the predetermined number of data sets when the storage means stores the data set at the time of starting the engine at least twice, and uses the predetermined number of data sets to determine the intersection of VN at the later time point. The engine start performance judging device according to any one of claims 1 to 5, wherein the engine start performance judging device is predicted.   The engine start performance determination apparatus according to any one of claims 1 to 6, wherein only a data set acquired during a predetermined period before the subsequent time point is used as the data set at the time of engine start.   The engine speed (N) is obtained by detecting a change in the output voltage (V) of the power storage device at the time of starting the engine and calculating a period of the change in a predetermined calculation formula. The engine starting performance determination device according to any one of 1 to 7. An engine start performance determination device for determining start performance of the engine in a vehicle equipped with an engine and a power storage device,
Every time the engine of the vehicle is started, an intersection calculation for calculating an intersection point (VN intersection point) on the coordinates of the output voltage (V) of the power storage device and the engine speed (N) when the engine is started. Means,
Engine temperature detection means for detecting the temperature of the engine;
A power storage device internal state quantity detecting means for detecting an internal state quantity of the power storage device;
Each time the engine is started, the VN intersection calculated by the intersection calculation unit, the engine temperature detected by the engine temperature detection unit, and the internal state detected by the power storage device internal state amount detection unit Storage means for storing a data set at the time of engine start including a quantity;
VN map construction means for constructing a VN map for each engine temperature and power storage device internal state quantity based on the stored data set, and storing it in the storage means;
The engine temperature at the later time point detected by the engine temperature detecting means at the time point after the engine start, the internal state quantity at the later time point detected by the power storage device internal state quantity detecting means, and the Intersection prediction means for predicting the intersection of VN at the later time point based on the VN map stored in the storage means;
An engine start performance determination device comprising: determination means for determining the start performance of the engine at a later time based on the intersection of VN predicted by the intersection prediction means.

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