Patent ID: 12211321

DESCRIPTION OF EMBODIMENTS

Embodiments of a vehicle diagnosis method, a vehicle diagnosis system, and an external diagnosis device according to the present invention will be described in detail below with reference to the accompanying drawings.

[Configuration]

FIG.1is a block diagram showing an example of a configuration of a vehicle diagnosis system10that includes an external diagnosis device14according to an embodiment of the present invention and that performs a vehicle diagnosis method according to the embodiment.

The vehicle diagnosis system10includes a vehicle12as a diagnosis target, the external diagnosis device14that executes various diagnoses of the vehicle12from the outside of the vehicle12, and a host computer16that provides a parameter file necessary for various diagnoses to the external diagnosis device14.

The vehicle12and the external diagnosis device14are connected to each other by a communication cable22via connectors18and20. The external diagnosis device14can wirelessly communicate with the host computer16.

In this embodiment, the vehicle12is assumed to be a four-wheeled gasoline vehicle having a gasoline engine (not shown). However, the vehicle12may be any vehicle having an internal combustion engine, and may be, for example, a hybrid vehicle having a gasoline engine and an electric motor, a diesel engine vehicle using light oil as fuel, or a liquefied petroleum gas (LPG) vehicle using LPG as fuel. The number of wheels of the vehicle12is not limited to four, and the vehicle12may be a two-wheeled vehicle, a three-wheeled vehicle, a six-wheeled vehicle, or the like.

As shown inFIG.1, the vehicle12includes an engine electronic control unit24(hereinafter referred to as the “engine ECU24”) that controls an engine (not shown), an ignition switch26(hereinafter referred to as the “IGSW26”), an injector28, and various sensors30.

The engine ECU24is a computer including a microcomputer, and includes a central processing unit (CPU)32, a ROM as a memory (an EEPROM34in this embodiment), a random access memory (RAM)36, a communication interface38, input/output devices such as an A/D converter and a D/A converter, a timer serving as a timer unit, and the like.

By reading and executing programs recorded in the ROM, the CPU32functions as various function realizing units (function realizing means), such as, for example, a control unit, an arithmetic unit, and a processing unit. The ROM stores an ECU identification code (ECU ID) of the engine ECU24, in addition to various programs.

The IGSW26is a rotary switch. In the IGSW26, from the left side toward an instrument panel (not shown), an “OFF” position, an “ACC” (accessory) position, and an “ON” position can be selected. When the IGSW26is further rotated to the right (in the clockwise direction) from the “ON” position, it reaches the “ST” (engine start) position. As a result, the engine is started.

When the vehicle12has a so-called smart start function, the IGSW26may be a push switch used for the so-called smart start function.

In the present embodiment, when the IGSW26is in the “ACC” position or the “ON” position, electric power is supplied from a battery (not shown) to the engine ECU24. When the IGSW26is in the “OFF” position, the supply of electric power from the battery to the engine ECU24is basically stopped.

The injector28injects fuel into air that has passed through a throttle valve (not shown), based on an instruction from the engine ECU24.

The various sensors30include an engine speed sensor (NE sensor)40, a throttle opening sensor42, a water temperature sensor44, an02sensor46, an air flow meter48, and the like. The engine ECU24controls the fuel injection of the injector28based on the detection signals from the various sensors30.

The external diagnosis device14includes a central processing unit (CPU)50, a ROM52, a RAM54, a communication interface56, input/output devices such as an A/D converter and a D/A converter, a timer serving as a timer unit, and the like.

By reading and executing programs recorded in the ROM52, the CPU50functions as various function realizing units (function realizing means), such as, for example, a control unit, an arithmetic unit, and a processing unit. In the present embodiment, the CPU50functions as: a fuel consumption amount acquisition unit58that acquires a fuel consumption amount Afp described later from the engine ECU24; and a fuel consumption amount determination unit60that determines whether or not the fuel consumption amount Afp is equal to or less than a threshold value Th.

The external diagnosis device14is a dedicated terminal called, for example, a Line End Tester (LET) or the like, and is portable by the operator. Therefore, the external diagnosis device14is provided with: an input unit62constituted by a keyboard, a numeric keypad, a fuel consumption amount erasing button described later, and the like; a display unit64that displays the result of processing performed by the CPU50; and a speaker66that outputs sound such as an alarm.

The host computer16has a parameter file necessary for vehicle diagnosis performed by the external diagnosis device14. The parameter file includes various parameters necessary for vehicle diagnosis, such as an ECU identification code for identifying the engine ECU24, and the threshold value Th used for determining the fuel consumption amount Afp. The parameter file is installed in the external diagnosis device14in advance from the host computer16before the vehicle diagnosis is executed.

FIG.2shows an example of processes from a production line of the vehicle12to a dealer (delivery destination). As shown inFIG.2, the production line of a production plant of the vehicle12mainly includes a manufacturing process and an inspection process. Hereinafter, the entire production plant including the building and the site may be referred to as a “factory”. The manufacturing process includes a press process, a welding process, a painting process, and an assembly process. After a predetermined assembling operation is completed in the assembly process, a fuel tank of the vehicle12is supplied with fuel necessary, for example, for the vehicle12to travel in subsequent processes after the assembly process. When the fuel is supplied to the vehicle12, the vehicle12proceeds to the inspection process. The vehicle12that has passed the inspection is moved out of the factory, and is delivered to a dealer (delivery destination) through a logistics process.

The threshold value Th used for determining the fuel consumption amount Afp is a predetermined value equal to or greater than a value calculated, for example, by adding a minimum amount of fuel required for traveling and idling of the vehicle12in the inspection process, and a minimum amount of fuel required for traveling and idling of the vehicle12in the factory other than in the inspection process, after the fuel has been supplied to the vehicle12after the assembly process of the production line. The threshold value Th is set in advance for each vehicle type.

[Operation]

The operation of the vehicle diagnosis system10including the external diagnosis device14basically configured as described above will be described in detail with reference to flowcharts shown inFIGS.3and4. Unless otherwise specified, the CPU32and the CPU50execute the processing shown in the flowchart. However, since it is redundant to refer to the CPU32and the CPU50each time, they are referred to as necessary.

[Acquisition of Fuel Consumption Amount Afp]

A flow in which the CPU32acquires the fuel consumption amount Afp of the vehicle12and stores it in the RAM36will be described with reference toFIG.3.

Here, the initial state is a state immediately after fuel required for traveling or the like of the vehicle12is supplied to the fuel tank (not shown) of the vehicle12after a predetermined assembling operation is completed in the assembly process of the production line. In other words, the initial state is a state immediately before the vehicle12is inspected in the inspection process.

In this initial state, the external diagnosis device14is connected to the vehicle12via the connectors18and20and is supplied with power from a battery (not shown) of the vehicle12. The parameter file necessary for the vehicle diagnosis is installed in the ROM52of the external diagnosis device14.

As shown inFIG.3, in step S1, it is confirmed whether or not the position of the IGSW26is changed to “ON”. Here, it is assumed that the position of the IGSW26changes from “ON” to “ST” and returns to “ON”, and the engine of the vehicle12starts.

Next, the process proceeds from step S1to step S2, and the CPU32reads a previous fuel consumption amount Afb from the EEPROM34, and writes it into the RAM36as the fuel consumption amount Afp (Afp<−Afb).

Here, since the state where the IGSW26is turned “ON” for the first time after the fuel has been supplied to the fuel tank of the vehicle12is assumed, the previous fuel consumption amount Afb read from the EEPROM34is initialized to 0.

In step S3, the CPU32acquires a fuel injection amount ΔAfi for each minute time from the injector28.

In step S4, the CPU32calculates a new fuel consumption amount Afp as an integrated value by adding the fuel injection amount ΔAfi for each minute time acquired in step S3to the fuel consumption amount Afp after rounding up the fraction of the fuel injection amount ΔAfi in units of 10 cubic centimeters, for example. The CPU32stores the new fuel consumption amount Afp in the RAM36(Afp<−Afp+ΔAfi).

Next, the process proceeds to step S5, and it is confirmed whether or not the IGSW26is “OFF”. While the IGSW26is “ON” (step S5: NO), step S3and step S4are repeatedly executed at a predetermined interval (for example, a cycle of several milliseconds to several hundred milliseconds).

On the other hand, when it is confirmed that the IGSW26is turned “OFF” in step S5(step S5: YES), the CPU32reads the fuel consumption amount Afp stored in the RAM36, and records it in the EEPROM34as the previous fuel consumption amount Afb (Afb<−Afp).

When the IGSW26is turned “OFF”, the power supply to the engine ECU24is stopped. Therefore, the fuel consumption amount Afp in the RAM36, which is a volatile memory, is erased (reset). On the other hand, the previous fuel consumption amount Afb in the EEPROM34, which is a nonvolatile memory, is not erased (not reset) and is held in the EEPROM34.

When the IGSW26is turned “ON” next time, the processing shown inFIG.3is restarted (from step S1). In step S2, the previous fuel consumption amount Afb is read from the EEPROM34, and is written into the RAM36as the fuel consumption amount Afp (Afp<−Afb). After step S3, the fuel injection amount ΔAfi for each minute time is added to the fuel consumption amount Afp in the RAM36, whereby a new fuel consumption amount Afp as an integrated value is calculated (Afp<−Afp+ΔAfi).

[Fuel Consumption Amount Determination Processing]

Next, the flow of fuel consumption amount determination processing performed by the external diagnosis device14will be described with reference toFIG.4.

The external diagnosis device14according to the embodiment of the present invention can be used for vehicle diagnosis in various environments such as vehicle diagnosis in a repair plant as well as vehicle diagnosis in a production plant (factory) of the vehicle12. Hereinafter, the operation of the external diagnosis device14will be described by taking, as an example, vehicle diagnosis performed in an “inspection process (pre-shipment inspection)” or the like in the production plant (factory) of the vehicle12.

As shown inFIG.4, in step S11, the CPU50of the external diagnosis device14checks various parameters and establishes a communication connection with the engine ECU24.

When the communication connection between the external diagnosis device14and the engine ECU24is established, the process proceeds to step S12, and the fuel consumption amount acquisition unit58of the CPU50requests the engine ECU24to transmit the fuel consumption amount Afp. (The CPU50transmits a request command to the engine ECU24.)

The engine ECU24that has received the request command reads the fuel consumption amount Afp from the RAM36and transmits it to the external diagnosis device14. In step S13, the fuel consumption amount acquisition unit58of the external diagnosis device14receives the fuel consumption amount Afp from the engine ECU24.

When the fuel consumption amount acquisition unit58receives the fuel consumption amount Afp from the engine ECU24, then in step S14, the fuel consumption amount determination unit60of the external diagnosis device14compares the fuel consumption amount Afp with the threshold value Th set in the parameter file in advance.

In step S14, when the fuel consumption amount Afp is equal to or less than the threshold value Th (Afp≤Th, step S14: YES), it is determined that the amount of fuel (fuel consumption amount Afp) consumed by the vehicle12during traveling and idling in the factory is within an appropriate range. The determination result by the fuel consumption amount determination unit60is “pass (OK)”.

When the result of the fuel consumption amount determination is “pass (OK)”, the process proceeds to step S15. The CPU50causes both the value of the fuel consumption amount Afp and the determination result to be simultaneously displayed on the display unit64. For example, the CPU50causes “Gas Consumption: 1.0 L/Shipment: “OK” to be displayed on the display unit64. The display of the determination result of “pass (OK)” also serves as permission (work instruction) for transferring the vehicle12to the next process. The operator who has confirmed the determination result transfers the vehicle12to the logistics process, which is the next process.

On the other hand, when the fuel consumption amount Afp is greater than the threshold value Th (Afp>Th, step S14: NO), it is determined that the amount of fuel (fuel consumption amount Afp) consumed by the vehicle12during traveling and idling in the factory exceeds the appropriate range and is in the inappropriate range. The determination result by the fuel consumption amount determination unit60is “fail (NG)”.

When the result of the fuel consumption amount determination is “fail (NG)”, the process proceeds to step S16. The external diagnosis device14causes both the value of the fuel consumption amount Afp and the determination result to be simultaneously displayed on the display unit64. For example, the CPU50causes “Gas Consumption: 3.0 L/Shipment: NG” to be displayed on the display unit64.

Further, in step S17, the external diagnosis device14displays, on the display unit64, a notification (additional fuel supply instruction) to prompt the operator to supply additional fuel. For example, the CPU50causes characters “Please supply additional fuel” to be displayed on the display unit64. In order to attract the attention of the operator, it is preferable that the characters are displayed on the display unit64in a blinking manner, or a warning sound is emitted from the speaker66. The operator who has confirmed the display of the characters can supply necessary fuel according to the value of the fuel consumption amount Afp.

[Comparison Between Comparative Example and Example of Embodiment]

An initial fuel supply amount for the vehicle12in the production line will be described by comparing a comparative example and an example according to an embodiment of the present invention with reference toFIG.5.

In the upper row ofFIG.5, a “comparative example” is illustrated. The “comparative example” is a hypothetical example for explaining the initial fuel supply amount for the vehicle12. In the “comparative example”, for example, a total of 10.0 liters of fuel is supplied to the vehicle12as the initial fuel supply amount in the production line.

As shown inFIG.5, the breakdown of the initial fuel supply amount of the “comparative example” is as follows: the amount of fuel required for the first explosion of the engine is 2.25 liters; the amount of fuel required for traveling and idling in the inspection process is 1.0 liter; the amount of fuel required for traveling in the factory, excluding in the inspection process and adjustment work, is 0.25 liters; when it is determined in the inspection process that adjustment work is necessary and the vehicle12is returned to the subsequent process, the amount of fuel required for the adjustment work is 3.0 liters; the amount of fuel required for idling in the factory, excluding in the inspection process and adjustment work, is 3.0 liters; and the amount of fuel required for traveling and idling in the logistics process after the vehicle12is shipped from the factory is 0.5 liters.

In general, it is known that the amount of fuel consumed in the factory after the fuel is supplied to the vehicle12in the production line varies greatly from vehicle to vehicle. This is because, after the inspection process, depending on whether or not the adjustment work is performed, the travel distance of the vehicle in the factory varies from vehicle to vehicle, and depending on the operating conditions of the production line, the length of the idle time varies from vehicle to vehicle.

From the viewpoint of prevention of fuel shortage, when the vehicle12is shipped from the factory, it is necessary for the fuel tank to store a larger amount of fuel than the minimum amount required in the logistics process or the like after shipment.

In the “comparative example”, the operator does not confirm the amount of fuel consumed by the vehicle12in the factory after the fuel is supplied to the vehicle12in the production line. Therefore, the initial fuel supply amount in the “comparative example” is set to an amount with a margin, assuming a case where the travel distance in the factory is the longest and the idle time in the factory is the longest.

On the other hand, in the “example”, the operator can confirm the fuel consumption amount Afp actually consumed in the factory, by using the external diagnosis device14(step S15and step S16inFIG.4). Therefore, additional fuel can be supplied to the vehicle12for which the fuel consumption amount Afp exceeds the threshold value Th. On the other hand, the vehicle12, for which the fuel consumption amount Afp is equal to or less than the threshold value Th, can be shipped from the factory without being supplied with additional fuel.

Therefore, in the “example” illustrated in the lower row ofFIG.5, the amount of fuel required for the adjustment work is 0 liters, and the amount of fuel required for idling is 1.0 liter. Thus, the initial fuel supply amount in the “example” is 5.0 liters in total, which is half the amount in the “comparative example”. Further, in the “example”, additional fuel may be supplied only to some vehicles12for which the fuel consumption amount Afp exceeds the threshold value Th. In this way, in the “example”, the initial fuel supply amount for the vehicle12can be reduced to the minimum necessary amount. Since the operator can know the fuel consumption amount Afp in the factory as necessary and can supply the fuel in an amount required for each vehicle without excess or deficiency, it is possible to optimize the amount of fuel supplied to the vehicles12in the factory (the entire production plant of the vehicle12).

In this “example”, the threshold value Th set in the external diagnosis device14is a predetermined value equal to or greater than 2.25 liters obtained, for example, by adding together: the amount of fuel (1.0 liter) required for traveling and idling in the inspection process; the amount of fuel (0.25 liters) required for traveling in the factory, excluding in the inspection process and adjustment work; and the amount of fuel (1.0 liter) required for idling in the factory, excluding in the inspection process and adjustment work.

Modified Example

A modified example will be described with reference to a flowchart ofFIG.6.

In the above-described example, in step S17ofFIG.4, when the notification prompting the supply of additional fuel is displayed on the display unit64, the processing related to the fuel consumption amount determination ends. The modified example illustrated inFIG.6is different from the above-described example in that steps S18to S20are added after step S17.

Specifically, after step S17, a step of erasing (resetting) the fuel consumption amount Afp and the previous fuel consumption amount Afb that are recorded in the engine ECU24is added.

In this modified example, after step S17, the external diagnosis device14receives an operation, by the operator, of pressing down a fuel consumption amount erase button (not shown) in step S18.

When the operator presses down the fuel consumption amount erase button (step S18: YES), a clear command is transmitted to the engine ECU24in step S19.

The operation of (the CPU32of) the engine ECU24that has received the clear command will be described with reference toFIG.7.

In step S191, the engine ECU24receives the clear command from the external diagnosis device14. In step S192, the engine ECU24erases (resets) the fuel consumption amount Afp held in the RAM36and the previous fuel consumption amount Afb held in the EEPROM34.

In step S193, the engine ECU24saves the erasure history in the EEPROM34. The process proceeds to step S194, and the engine ECU24gives a response indicating that the erasing processing has been completed, to the external diagnosis device14.

In step S192, the engine ECU24may simultaneously erase the fuel consumption amount Afp and the previous fuel consumption amount Afb. Alternatively, the engine ECU24may first erase one of the fuel consumption amount Afp and the previous fuel consumption amount Afb, and then erase the remaining one.

The external diagnosis device14receives the response indicating that the erasing processing has been completed, from the engine ECU24. Returning toFIG.6, in step S20, the display unit64displays completion of the erasing processing. As a result, the processing related to the fuel consumption amount determination ends.

In the case where the operator does not perform the operation of pressing down the fuel consumption amount erase button (step S18: NO), the clear command is not transmitted to the engine ECU24. In this case, after the elapse of a predetermined time, the processing related to the fuel consumption amount determination ends. The case where the operation of pressing down the fuel consumption amount erase button is not performed is, for example, a case where the operator desires to end the processing after confirming only the value of the fuel consumption amount Afp of the vehicle12and the result of the fuel consumption amount determination.

[Operation Flow in which Modified Example is Applied to Production Line]

Next, an operation flow, in which the above-described modified example is applied to an inspection process and an adjustment process in the production line of the vehicle12, will be described with reference toFIG.8.

First, at the end of the assembly process, fuel for traveling or the like in the subsequent processes (an inspection process and a logistics process in this modified example) after the assembly process is supplied to the vehicle12by an automated fuel dispenser or the like (step S21).

Next, the process proceeds to step S22. In the inspection process, the operator inspects whether or not the adjustment work is necessary for the vehicle12. The inspection items are, for example, whether or not adjustment work is necessary for welded portions, and whether or not adjustment work is necessary for assembling components. Here, a case is explained where it is determined that the adjustment work is not necessary (step S22: NO).

Next, in step S23, the operator performs fuel consumption amount determination by using the external diagnosis device14. The fuel consumption amount determination processing corresponds to steps S11to S17inFIGS.4and6. When the result of the fuel consumption amount determination is “pass (OK)” (step S23: OK), the process proceeds to step S24. The vehicle12is shipped from the factory and proceeds to the logistics process. When the result of the fuel consumption amount determination is “fail (NG)” (step S23: NG), the process proceeds to step S26described later.

On the other hand, when it is determined in step S22that the adjustment work is necessary for the vehicle12(step S22: YES), the vehicle12is moved out of the production line, and is then returned to the manufacturing process according to the item for which the adjustment work is necessary. (For example, when the adjustment work is necessary for welded portions, the vehicle12is returned to the welding process, and when the adjustment work is necessary for assembling components, the vehicle12is returned to the assembly process.)

When the adjustment work of the vehicle12is completed in step S25, the process proceeds to step S26. The operator uses the external diagnosis device14to perform fuel consumption amount determination. The fuel consumption amount determination processing corresponds to steps S11to S17inFIGS.4and6.

In step S26, when the result of the fuel consumption amount determination is “pass (OK)” (step S26: OK), the vehicle12is returned to the inspection process, and the process proceeds to step S22.

In step S26, when the result of the fuel consumption amount determination is “fail (NG)” (step S26: NG), the process proceeds to step S27. The operator supplies additional fuel to the vehicle12based on an instruction from the external diagnosis device14.

Next, in step S28, the operator performs an operation of pressing down the fuel consumption amount erase button to erase the fuel consumption amount Afp and the previous fuel consumption amount Afb that are recorded in the engine ECU24. The erasing processing corresponds to steps S18to S20inFIG.6.

In step S29, it is determined whether further adjustment work is necessary for the vehicle12. When it is determined that the adjustment work is not necessary (step S29: NO), the vehicle12is returned to the inspection process, and the process proceeds to step S22.

When it is determined in step S29that the adjustment work is still necessary (step S29: YES), the vehicle12is returned to step S25, and the adjustment work is performed again on the vehicle12.

Hereinafter, the invention that can be grasped from the above-described embodiment and modified example will be described. For convenience of understanding, the components are denoted by the reference numerals used in the above-described embodiment and modified example. However, the components are not limited to those denoted by the reference numerals.

The vehicle diagnosis method according to the present invention is a vehicle diagnosis method for, after fuel is supplied to a vehicle12in a production line of the vehicle12, diagnosing whether or not a fuel consumption amount Afp of the vehicle12is appropriate by using an external diagnosis device14that communicates with an engine ECU (electronic control unit)24mounted on the vehicle12, the vehicle diagnosis method comprising: a step of causing the engine ECU24to calculate and store a fuel consumption amount Afp (step S4); a step of causing the external diagnosis device14to acquire the fuel consumption amount Afp from the engine ECU24(step S13); a step of causing the external diagnosis device14to determine whether the fuel consumption amount Afp is equal to or less than a threshold value Th (step S14); and a step of causing the external diagnosis device14to permit transfer of the vehicle12to a next process (step S15) when determining that the fuel consumption amount Afp is equal to or less than the threshold value Th (step S14: YES), and to give an instruction to supply additional fuel (step S17) when determining that the fuel consumption amount Afp is greater than the threshold value Th (step S14: NO).

According to this feature, after the fuel is supplied to the vehicle12in the production line of the vehicle12, the operator can supply (inject) additional fuel according to an actual fuel consumption amount Afp. Therefore, the fuel required for each vehicle can be supplied thereto without excess or deficiency while reducing the initial fuel supply amount for the vehicle12to the minimum necessary amount. It is possible to optimize the fuel supply amount (including the additional fuel supply amount) for the vehicles12in the entire plant (factory).

The threshold value Th may be set based on an amount of fuel required for the vehicle12to travel in the plant (factory) after the fuel is supplied to the vehicle12in the production line. Thus, the fuel in an amount required in the logistics process or the like after the vehicle12is shipped from the factory can be reliably left in the fuel tank. This can prevent fuel shortage after the vehicle12is shipped from the factory.

Further, the amount of fuel required for the vehicle12to travel in the plant (factory) may include an amount of fuel required for idling. Thus, the fuel in an amount required in the logistics process or the like after the vehicle12is shipped from the factory can be reliably left in the fuel tank. This can prevent fuel shortage after the vehicle12is shipped from the factory

Furthermore, the vehicle diagnosis method may further comprise, after the step of causing the external diagnosis device14to determine whether or not the fuel consumption amount Afp is equal to or less than the threshold value Th (step S14), a step of causing the engine ECU24to erase the fuel consumption amount Afp based on an instruction from the external diagnosis device14(step S19).

According to this feature, for example, in a case where the operator supplies additional fuel to the vehicle12, the engine ECU24can calculate and store the fuel consumption amount Afp after the additional fuel is supplied. Therefore, in the next fuel consumption amount determination, it is possible to determine whether or not the fuel consumption amount Afp after the additional fuel is supplied is appropriate.

Furthermore, the fuel consumption amount Afp may be calculated based on a fuel injection amount ΔAfi of an injector28. According to this feature, it is possible to calculate the fuel consumption amount Afp more accurately than with other fuel consumption amount calculation methods such as a full tank method.

Furthermore, the engine ECU24may include a RAM36(volatile memory) and a nonvolatile memory such as an EEPROM34, and the step of causing the engine ECU24to calculate and store the fuel consumption amount Afp (step S3and step S4) may include a step of causing the engine ECU24to read the fuel consumption amount Afp from the RAM36and store the fuel consumption amount Afp in the EEPROM34as a previous fuel consumption amount Afb, when an ignition switch (IGSW)26is turned off (step S6), and a step of causing the engine ECU24to write the previous fuel consumption amount Afb stored in the EEPROM34, into the RAM36as the fuel consumption amount Afp, when the IGSW26is turned off and then turned on again (step S2).

When the IGSW26is turned off in the inspection process or the like, the power supply to the RAM36is stopped and the information related to the fuel consumption amount Afp stored in the RAM36is erased. However, when the IGSW26is turned on again, the previous fuel consumption amount Afb at the time when the IGSW26is turned off is written into the RAM36as the fuel consumption amount Afp. Therefore, the engine ECU24can continuously calculate and store the fuel consumption amount Afp regardless of the ON/OFF operation of the IGSW26.

The vehicle diagnosis system according to the present invention is a vehicle diagnosis system10that, after fuel is supplied to a vehicle12in a production line of the vehicle12, diagnoses whether or not a fuel consumption amount Afp of the vehicle12is appropriate by using an external diagnosis device14that communicates with an engine ECU24mounted on the vehicle12, wherein the engine ECU24includes a RAM36(storage unit) configured to store a fuel consumption amount Afp, the external diagnosis device14includes a fuel consumption amount acquisition unit58configured to acquire the fuel consumption amount Afp from the engine ECU24, and a fuel consumption amount determination unit60configured to determine whether or not the fuel consumption amount Afp is equal to or less than a threshold value Th, and the fuel consumption amount determination unit60permits transfer of the vehicle12to a next process when determining that the fuel consumption amount Afp is equal to or less than the threshold value Th, and gives an instruction to supply additional fuel when determining that the fuel consumption amount Afp is greater than the threshold value Th.

According to this feature, after the fuel is supplied to the vehicle12in the production line of the vehicle12, the operator can supply additional fuel according to an actual fuel consumption amount Afp. Therefore, the fuel required for each vehicle can be supplied thereto without excess or deficiency while reducing the initial fuel supply amount for the vehicle12to the minimum necessary amount. It is possible to optimize the fuel supply amount (including the additional fuel supply amount) for the vehicles12in the entire plant (factory).

Further, the external diagnosis device according to the present invention is an external diagnosis device14that, after fuel is supplied to a vehicle12in a production line of the vehicle12, diagnoses whether or not a fuel consumption amount Afp of the vehicle12is appropriate by communicating with an engine ECU24mounted on the vehicle12, the external diagnosis device14comprising a fuel consumption amount acquisition unit58configured to acquire the fuel consumption amount Afp from the engine ECU24, and a fuel consumption amount determination unit60configured to determine whether or not the fuel consumption amount Afp is equal to or less than a threshold value Th, and the fuel consumption amount determination unit60permits transfer of the vehicle12to a next process when determining that the fuel consumption amount Afp is equal to or less than the threshold value Th, and gives an instruction to supply additional fuel when determining that the fuel consumption amount Afp is greater than the threshold value Th.

According to this feature, after the fuel is supplied do the vehicle12in the production line of the vehicle12, the operator can supply additional fuel according to an actual fuel consumption amount Afp. Therefore, the fuel required for each vehicle can be supplied thereto without excess or deficiency while reducing the initial fuel supply amount for the vehicle12to the minimum necessary amount. It is possible to optimize the fuel supply amount (including the additional fuel supply amount) for the vehicles12in the entire plant (factory).

In the above-described embodiment, the determination result is displayed in step S16inFIG.4, and thereafter, the instruction is displayed in step S17inFIG.4. However, the determination result and the instruction may be displayed simultaneously. For example, if “Gas Consumption: 3.0 L/Shipment: NG/Please supply additional fuel” is displayed, the operator can instantly determine whether or not it is necessary to supply additional fuel to the vehicle12. Therefore, it is possible to reduce time loss of work.

In addition, in the above-described embodiment, the determination results are displayed in step S15and step S16inFIG.4and the instruction is displayed in step S17inFIG.4on the display unit64of the external diagnosis device14, however the determination results and the instruction may be displayed on a separate display unit provided in the vehicle12, such as an instrument meter of an instrument panel (not shown) of the vehicle12or a display of a car navigation system of the vehicle12.

It should be noted that the present invention is not limited to the above-described embodiment and can adopt various configurations without departing from the gist of the present invention.