JP4636175B2 - Vehicle diagnostic device - Google Patents

Description

  The present invention relates to a diagnosis device for a vehicle driven by an internal combustion engine, and more particularly to a device for diagnosing the fuel consumption of a vehicle.

Various methods have been proposed for calculating the fuel consumption of a vehicle, particularly a vehicle driven by an internal combustion engine. For example, Japanese Patent Application Laid-Open No. 2006-183506 discloses a method for calculating fuel consumption based on a fuel injection amount and torque. According to this method, the output of the internal combustion engine is calculated from the torque and the rotational speed in a predetermined period, the total fuel supply amount in the predetermined period is calculated, and the fuel consumption is calculated from the relationship between the engine output and the total fuel supply amount. Is done.
JP 2006-183506 A JP 2006-118480 A

  By the way, the factors that affect the fuel consumption of the vehicle include the use conditions of the vehicle, the driving state of the driver, and the state of the vehicle itself. A conventionally proposed method for calculating fuel consumption is a method for calculating total fuel consumption including all these factors, as is the method disclosed in Japanese Patent Application Laid-Open No. 2006-183506.

  However, when an attempt is made to improve the fuel consumption based on the calculation result, whether the use conditions of the vehicle and the driving state of the driver have an effect on the fuel consumption, or the state of the vehicle itself (for example, an internal combustion engine due to changes over time) The content of the improvement measures will differ depending on whether the deterioration of the fuel is affecting fuel efficiency. For example, when the deterioration in fuel consumption is caused by the former factor, it can be improved by reviewing the use conditions or changing the way of driving. On the other hand, when the deterioration in fuel consumption is caused by the latter factor, it is necessary to inspect and maintain the vehicle in order to improve it, and there is a possibility that it cannot be improved so much depending on the progress of deterioration of the vehicle. Conventionally proposed fuel consumption calculation methods cannot determine whether the deterioration of fuel consumption is due to the former factor or the latter factor.

  The present invention has been made in order to solve the above-described problems, and is a vehicle diagnosis capable of calculating the fuel consumption determined by the state of the vehicle itself by eliminating the influence of the driving state and use conditions on the fuel consumption. An object is to provide an apparatus.

In order to achieve the above object, a first invention is a diagnostic apparatus for a vehicle driven by an internal combustion engine,
Drive system model storage means for storing a drive system model for calculating back the torque and rotation speed of the internal combustion engine from the vehicle speed and acceleration;
Map data storage means for storing map data in which fuel consumption is associated with torque and rotation speed of the internal combustion engine;
Map data updating means for updating the map data based on an actual control result of the internal combustion engine;
Driving pattern acquisition means for acquiring a driving pattern for diagnosis defined by vehicle speed;
Changes in torque and rotational speed of the internal combustion engine when the vehicle is driven in the driving pattern are calculated by the drive system model, and the vehicle is driven in the driving pattern using the calculation result and the map data. Fuel consumption calculation means for calculating the fuel consumption of the case,
It is characterized by having.

According to a second invention, in the first invention,
The drive system model storage means can rewrite coefficients or constants relating to the specifications of the vehicle among the coefficients or constants constituting the drive system model.

According to a third invention, in the first or second invention,
The map data updating means updates the map data using actual values of fuel consumption, rotation speed, and torque.

4th invention is 1st or 2nd invention,
The map data updating means updates the map data using actual values of fuel consumption and rotation speed and required torque.

According to a fifth invention, in the first or second invention,
The map data updating means updates the map data by using actual values of fuel consumption and rotation speed and estimated torque estimated from the operating state of the internal combustion engine.

According to a sixth invention, in the fifth invention,
The map data update means calculates the estimated torque from the in-cylinder pressure measured by the in-cylinder pressure sensor.

A seventh invention is the invention according to any one of the first to sixth inventions,
The apparatus further comprises warning means for comparing the calculation result by the fuel consumption calculation means with a predetermined reference value and issuing a warning when the calculation result is worse than the reference value.

  According to the first aspect of the present invention, changes in the torque and the rotational speed of the internal combustion engine when the vehicle is driven in the diagnostic traveling pattern are calculated by the drive system model, and the calculated result and the fuel consumption amount are included in the torque and the rotational speed. The fuel efficiency is calculated using the map data associated with. The fuel efficiency calculated in this way is the fuel efficiency when the vehicle is driven in the diagnostic driving pattern under the predetermined conditions defined in the drive system model, and is affected by the use condition of the vehicle and the driving state of the driver. Has not received. Moreover, since the map data is updated based on the actual control result of the internal combustion engine, the state of the vehicle itself, in particular, the state of the internal combustion engine is steadily reflected in the calculation result of the fuel consumption. According to the first invention, it is possible to calculate the fuel consumption determined by the state of the vehicle itself by eliminating the influence of the driving state and use conditions on the fuel consumption, and to diagnose the vehicle fairly based on the calculation result. it can.

  According to the second aspect of the present invention, the fuel consumption determined by the state of the vehicle itself can be calculated more accurately by rewriting the coefficient or constant related to the specifications of the vehicle in accordance with the measured state of the vehicle.

  According to the third aspect of the invention, the actual state of the internal combustion engine can be steadily reflected in the map data by using the actual values of the fuel consumption, the rotational speed, and the torque for updating the map data.

  According to the fourth aspect of the invention, the actual state of the internal combustion engine can be obtained even when there is no means for actually measuring the torque by using the actual values of the fuel consumption and the rotational speed and the required torque for updating the map data. Can be steadily reflected in the map data.

  According to the fifth aspect of the present invention, when the map data is updated, the actual values of the fuel consumption and the rotational speed and the estimated torque estimated from the operating state of the internal combustion engine are used, so that there is no means for actually measuring the torque. Even so, the state of the internal combustion engine can be steadily reflected in the map data.

  According to the sixth invention, the torque can be estimated with high accuracy by using the in-cylinder pressure measured by the in-cylinder pressure sensor.

  According to the seventh aspect of the invention, a warning is issued when the fuel efficiency is deteriorated, so that the vehicle driver or user can be urged to inspect and maintain the vehicle.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  A vehicle to be diagnosed in the present embodiment is a vehicle driven by an internal combustion engine (hereinafter simply referred to as an engine), and a vehicle having a manual transmission or an electromagnetic clutch type automatic transmission in the drive system. . There is no limitation on the type of engine. The diagnostic device of the present embodiment is realized as one function of a control device provided in such a vehicle. FIG. 1 is a block diagram showing the configuration when the vehicle control device functions as a diagnostic device. The configuration shown in FIG. 1 is a configuration that is virtually realized by the CPU of the control device operating according to a program stored in the memory of the control device.

  As shown in FIG. 1, the diagnostic apparatus is composed of five elements 2, 4, 6, 8, and 10. One of the elements constituting the diagnostic device is a travel mode data storage unit 2 that stores travel mode data for diagnosis. The driving mode data is a diagnostic driving pattern defined by the vehicle speed, and is represented by a graph as shown in FIG. Specific examples of the travel pattern include travel patterns defined in the 10.15 mode or the US LA4 mode. The driving mode data stored in the driving mode data storage unit 2 can be rewritten from the outside.

  The fuel consumption calculation unit 4 is included in the components of the diagnostic apparatus. The fuel consumption calculation unit 4 calculates the fuel consumption of the vehicle using a fuel consumption model. The fuel consumption model is a calculation model for calculating the fuel consumption from the driving mode data. Hereinafter, the fuel efficiency X [km / l] calculated by the fuel efficiency model is referred to as mode fuel efficiency. The fuel consumption model is composed of a drive system model and a fuel consumption map. FIG. 3 is a conceptual diagram of a drive system model. As shown in this figure, the drive train model models the torque and rotation transmission characteristics from the engine to the tire. By calculating the drive system model from the reverse direction, the engine speed Ne and the torque Te can be calculated backward from the travel mode data. In the fuel consumption map, the fuel consumption q [g / s] is associated with the engine speed Ne [rpm] and the torque Te [Nm]. A method for calculating the mode fuel consumption X using the drive system model and the fuel consumption map will be described in detail later.

  The diagnostic apparatus includes a fuel consumption OBD unit 6 as a component. The fuel consumption OBD unit 6 performs fuel consumption diagnosis based on the mode fuel consumption calculated using the fuel consumption model. Based on the result of the fuel consumption diagnosis, a warning to the driver or the user is given using a warning lamp in the vehicle interior (not shown). The detailed flow of fuel consumption diagnosis by the diagnostic device will be described later.

  Moreover, the map data learning part 8 is contained in the component of a diagnostic apparatus. The map data learning unit 8 learns the relationship between the engine speed and torque and the fuel consumption based on the actual control result of the internal combustion engine, and updates the fuel consumption map at a predetermined update period based on the learning result. . However, the learning by the map data learning unit 8 is performed only when the engine is in a normal control state. The normal control state means a state where special control such as catalyst warm-up operation during cold start and rich spike for catalyst regeneration is not performed. The information used for learning is an actual value measured by the crank angle sensor for the engine speed, and an actual value calculated from the fuel injection amount for the fuel consumption. Regarding the torque, an actual value measured by the torque sensor can be used in an engine including a torque sensor. In an engine that does not include a torque sensor, if any cylinder has a cylinder pressure sensor (CPS), an estimated torque calculated based on the cylinder pressure can be used. In an engine that is not provided with a torque sensor or an in-cylinder pressure sensor, use an estimated torque calculated based on the intake air amount, ignition timing, and air-fuel ratio, or use a required torque calculated from the accelerator operation amount, etc. Can do.

  Furthermore, the diagnostic apparatus includes a model data input unit 10 as a component. This model data input section contains various data that make up the drivetrain model, specifically vehicle specifications such as vehicle weight and tire diameter, various loss factors such as rolling friction coefficient, and transmission shift patterns. 10 can be input. For example, when the tire diameter and the rolling friction coefficient change due to the tire replacement, the drive system model can be updated to the latest one according to the actual vehicle by rewriting the data of the drive system model.

  Next, the procedure of the fuel consumption diagnosis by the diagnostic apparatus of this embodiment will be described using the flowchart of FIG. As shown in FIG. 4, in the first step S2 of the fuel consumption diagnosis, the fuel consumption calculation unit 4 calculates the mode fuel consumption X using the fuel consumption model. The processing in this step is executed at a relatively long predetermined cycle or at a predetermined timing such as when the engine is started. A specific fuel consumption calculation procedure based on the fuel consumption model will be described later.

In the next step S4, determination by the fuel consumption OBD unit 6 is performed. The fuel consumption OBD unit 6 determines whether or not the following relationship is satisfied with respect to the mode fuel consumption X calculated by the fuel consumption calculation unit 4. X _ini is a reference value, and a catalog value or a measured value at the time of a new vehicle is used. a is a coefficient having a value smaller than 1. The value of a is set to such a value that it can be determined that there is no problem in fuel consumption in the vehicle itself at least as long as the following relationship holds.
X> a · X _ini

  While the above relationship is established, the process of step S2 and the determination of step S4 are repeated.

  When the above relationship no longer holds, that is, when the mode fuel consumption X has deteriorated beyond the allowable value, the fuel consumption OBD unit 6 executes the process of step S6. The fuel consumption OBD unit 6 issues a warning to the driver by lighting or blinking a warning lamp on the vehicle interior, for example, on the instrument panel.

  As will be described below, the mode fuel efficiency calculated using the fuel efficiency model is a fuel efficiency determined by the state of the vehicle itself, and is a fair fuel efficiency evaluation index that is not affected by the use state of the vehicle or the driving state of the driver. It is. Therefore, when the mode fuel efficiency is deteriorated, there is a possibility that some problem has occurred in the vehicle. According to the diagnostic device of the present embodiment, a warning is issued when it is determined that the mode fuel efficiency is deteriorated as a result of the fuel consumption diagnosis, and thus the driver can be urged to inspect and maintain the vehicle.

  FIG. 5 is a flowchart showing the procedure of fuel consumption calculation executed by the fuel consumption calculation unit 4 in step S2. As shown in FIG. 5, the process of step S <b> 2 includes the processes from step S <b> 202 to step S <b> 214. As described above, the fuel consumption model is composed of the drive system model and the fuel consumption map, but the processing from step S202 to step S210 is the calculation by the drive system model, and the fuel consumption map is used for the processing of step S212. .

In the first step S202 of the fuel consumption calculation, the travel mode data is read from the travel mode data storage unit 2 into the fuel consumption calculation unit 4. The fuel consumption calculation unit 4 acquires the vehicle speed V [m / s] from the travel mode data, and calculates the acceleration α [m / s ² ] from the vehicle speed V. Specifically, the vehicle speed V is acquired at a predetermined time interval (for example, every 1 second) from the start to the end of the travel pattern defined by the travel mode data. Then, the acceleration α [m / s ² ] is calculated from the acquired vehicle speed V at the time interval.

In the next step S204, the fuel consumption calculation unit 4 calculates a running resistance R _all [N] based on the vehicle speed V and the acceleration α. The running resistance R _all can be calculated as the sum of the air resistance R _air and the rolling resistance R _roll as shown in the following equation.
R _all = R _air + R _roll

Each of the resistance values R _air and R _roll is calculated by a map prepared in advance by an experiment or by using a physical formula. These maps and physical formulas form part of the drive train model. Of the coefficients and constants used in the calculation, those that can change depending on the vehicle state such as the vehicle weight and the rolling friction coefficient of the tire can be rewritten via the model data input unit 10.

In the next step S206, the fuel consumption calculation unit 4 calculates the tire rotation speed Na [rpm] from the vehicle speed V by the following formula, and calculates the tire torque Ta [Nm] from the running resistance R _all . Here, R is the effective radius of the tire, which can also be rewritten via the model data input unit 10.
Na = V / (2 · π · R)
Ta = R _all · R

In the next step S208, the fuel consumption calculation unit 4 calculates the propeller shaft rotation speed Np [rpm] from the tire rotation speed Na by the following formula, and calculates the propeller shaft torque Tp [Nm] from the tire torque Ta. Here, i _D is the differential ratio of the differential gear (D / F), and ΔT _D is the torque loss at D / F. The value of [Delta] T _D physical expression, or is calculated by the map created in advance by experiments.
Np = Na · i _D
Tp = Ta / i _D + ΔT _D

In the next step S210, the fuel consumption calculation unit 4 calculates the engine speed Ne [rpm] from the propeller shaft speed Np by the following formula, and calculates the engine torque Te [Nm] from the propeller shaft torque Tp. Here, i _M is a gear ratio of the transmission (T / M), and _IE is an engine moment of inertia. In this embodiment, the transmission is manual. The value of the gear ratio i _M is determined in accordance with the shift pattern which is set in advance. This shift pattern is a shift pattern that is used for control if the transmission is an electromagnetic clutch type automatic transmission, and is a virtual shift pattern that is considered optimal in terms of fuel consumption if the transmission is a manual transmission. is there. The shift pattern also forms part of the drive train model. ΔT _M is the torque loss at T / M, and ΔT _E is the torque loss at the engine (Eng). Each value of ΔT _E and ΔT _M is calculated by a physical formula or a map created in advance by experiment.
Ne = Np · i _M
Te = Tp / i _M + ΔT _M + ΔT _E + I _E · i _D · i _M · α / R

  Through the processing from step S202 to step S210, the engine torque Te and the engine speed Ne when the vehicle is driven in the driving pattern defined by the driving mode data are calculated at predetermined time intervals. In the next step S212, the fuel consumption calculation unit 2 applies the calculation result of step S210 to the fuel consumption map, and at every predetermined time interval (here, every second) from the start to the end of the travel pattern defined by the travel mode data. The fuel consumption q [g / s] is calculated.

In the last step S214, the fuel consumption calculation unit 2 calculates the mode fuel consumption X using the time integral value of the vehicle speed V and the time integral value of the fuel consumption q as shown in the following equation. The integration interval of each time integration is from the start point to the end point of the driving pattern defined by the driving mode data. Ρ in the following equation is the fuel density.
X = ρ · ∫Vdt / ∫qdt × 10 ³

  As described above, the diagnosis device according to the present embodiment calculates changes in the engine torque and the engine speed when the vehicle is driven with a driving pattern for diagnosis using the drive system model, and the calculation result and the fuel consumption map. And calculate the mode fuel efficiency of the vehicle. The mode fuel efficiency calculated by the diagnostic device of the present embodiment is the fuel efficiency when the vehicle is driven with a driving pattern for diagnosis under a predetermined condition defined in the drive system model. It is not affected by the driving conditions of the driver. In addition, since the fuel consumption map data is updated by the map data learning unit 8 based on the actual control result of the engine, the state of the vehicle itself, in particular, the engine state is steadily reflected in the calculation result of the mode fuel consumption. ing.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention can also be applied to a vehicle equipped with a torque converter type automatic transmission. In that case, the process of step S210 in the flowchart of FIG. 5 may be replaced with the processes of steps S220, S222, S224, and S226 shown in the flowchart of FIG.

  The flowchart of FIG. 6 will be described. In step S220, the torque converter rotational speed Nc and the torque converter torque Tc are calculated based on the propeller shaft rotational speed Np and the propeller shaft torque Tp. This calculation uses a torque converter model in which the transfer characteristics of torque converter are modeled by physical formulas, empirical formulas or maps. In step S222, the engine speed Ne and the engine torque Te are calculated from the torque converter speed Nc and the torque converter torque Tc.

Although it is necessary to gear ratio i _M of the transmission in the calculation of the torque converter speed Nc and torque converter torque Tc, the decision is made in accordance with the shift position. Selection of the shift position is performed in step S226. In step S226, a shift position is selected from the shift diagram according to the throttle opening θ calculated in step S224. In step S224, the throttle opening degree θ is determined from a map prepared in advance based on the engine speed Ne and the engine torque Te calculated in step S222.

It is the schematic which shows the structure of the diagnostic apparatus of the vehicle as embodiment of this invention. It is a graph which shows an example of the running pattern for diagnosis concerning an embodiment of the invention. It is a conceptual diagram of the drive system model concerning embodiment of this invention. It is a flowchart which shows the procedure of the fuel consumption diagnosis implemented in embodiment of this invention. It is a flowchart which shows the flow of the procedure of the fuel consumption calculation implemented in embodiment of this invention. It is a flowchart which shows a part of procedure of the fuel consumption calculation in the case of applying this invention to the vehicle provided with the torque converter type automatic transmission.

Explanation of symbols

2 Driving mode data storage unit 4 Fuel consumption calculation unit 6 Fuel consumption OBD unit 8 Map data learning unit 10 Model data input unit

Claims (7)

A diagnostic device for a vehicle driven by an internal combustion engine,
Drive system model storage means for storing a drive system model for calculating back the torque and rotation speed of the internal combustion engine from the vehicle speed and acceleration;
Map data storage means for storing map data in which fuel consumption is associated with torque and rotation speed of the internal combustion engine;
Map data updating means for updating the map data based on an actual control result of the internal combustion engine;
Driving pattern acquisition means for acquiring a driving pattern for diagnosis defined by vehicle speed;
Changes in torque and rotational speed of the internal combustion engine when the vehicle is driven in the driving pattern are calculated by the drive system model, and the vehicle is driven in the driving pattern using the calculation result and the map data. Fuel consumption calculation means for calculating the fuel consumption of the case,
A vehicle diagnostic apparatus comprising:   2. The vehicle diagnosis apparatus according to claim 1, wherein the drive system model storage means can rewrite a coefficient or a constant related to the specifications of the vehicle among coefficients or constants constituting the drive system model. .   3. The vehicle diagnosis apparatus according to claim 1, wherein the map data updating unit updates the map data using actual values of fuel consumption, rotation speed, and torque.   3. The vehicle diagnosis apparatus according to claim 1, wherein the map data updating means updates the map data using actual values of fuel consumption and rotation speed and required torque.   3. The map data updating means updates the map data using actual values of fuel consumption and rotational speed and estimated torque estimated from an operating state of the internal combustion engine. The vehicle diagnostic apparatus as described.   6. The vehicle diagnosis apparatus according to claim 5, wherein the map data updating means calculates an estimated torque from an in-cylinder pressure measured by an in-cylinder pressure sensor.   The apparatus further comprises warning means for comparing a calculated value obtained by the fuel consumption calculating means with a predetermined reference value and issuing a warning when the calculated value is worse than the reference value. 7. The vehicle diagnostic apparatus according to any one of items 1 to 6.

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