JPS6257529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an economical fuel consumption driving instruction device for driving a vehicle.

In general, a vehicle internal combustion engine is designed so that it can operate with sufficient margin even if its load changes considerably, with the gear ratio of the gear transmission remaining the same. Therefore, especially when driving a vehicle such as a truck that has a gear type transmission with a large number of gears, the driver can select the gear ratio of the transmission appropriately to some extent and still be able to drive the vehicle without any problem.

However, such internal combustion engines for vehicles can be operated at a good fuel consumption rate, that is, at economical fuel efficiency, by appropriately setting the operating conditions at the same output power. and therefore,
In the recent energy-saving era, it is desirable to always set the gear ratio of the transmission appropriately or to keep the amount of depression of the accelerator pedal appropriate.

However, conventional economical and fuel efficient driving instruction devices that enable the realization of economical and fuel efficient driving as described above, for example, apply engine braking when driving downhill,
Operate the brake pedal and accelerate in an emergency.
When the amount of pedal depression becomes almost zero, an instruction is given to the driver to operate the accelerator pedal or to change gears, which may cause psychological turmoil to the driver.

Therefore, in view of the above-mentioned points, the present invention provides an accelerator pedal, which determines the state of output power of an internal combustion engine, among objects operated by a driver in a vehicle, in order to realize economical and fuel-efficient driving of a vehicle. An object of the present invention is to provide an improved economical and fuel efficient driving instruction device that instructs the combination of the amount of depression of the engine and the rotational speed of the internal combustion engine by selecting the gear ratio of the transmission to be always appropriate.

Furthermore, the present invention provides a versatile vehicle with an adjustable characteristic setting function so that it can be applied to various high fuel efficiency ranges determined by the purpose and type of vehicle or the type of internal combustion engine installed in the vehicle. The purpose is to provide an economical and fuel efficient driving instruction device.

First, before explaining the present invention, reference is made to FIG. 1 in order to explain the economical fuel efficiency of an internal combustion engine.

FIG. 1 illustrates general characteristics of a vehicle diesel engine, where the vertical axis T shows the output torque of the diesel engine, and the horizontal axis N shows its rotational speed. A loop-shaped broken line e indicates a constant fuel efficiency curve (gr/ps-h), and indicates that the fuel consumption rate (fuel efficiency rate) increases as the loop moves outward. Characteristic a1 indicated by a dot-dashed line is a characteristic when the amount of depression of the accelerator pedal is an arbitrary constant value, and the characteristic remains approximately in the shape of characteristic a1 depending on the amount of depression of the accelerator pedal. Move in the direction of the vertical axis in FIG.

Suppose now that a freight vehicle equipped with a diesel engine having the characteristics shown in Figure 1 is in an overtop transmission state (6-speed transmission, differential gear ratio x overtop gear ratio = 4.25), and is under 100% load. In a steady running state with a load and a running gradient of 0%, the running resistance characteristic of this freight vehicle is as shown by the broken line i.

When such a car runs on a highway at a speed of about 90 km/h, the engine speed of the diesel engine becomes No, c indicates the constant boundary of No, and the output torque T at this time becomes the operating point f. .

When a freight vehicle traveling with the above-mentioned running resistance travels on an expressway, as is clear from Figure 1, it must travel at an engine speed as close as possible to the loop center of the equal fuel efficiency curve e. Desirably, for this purpose, the
It is best to drive by keeping the vehicle speed below ＝No.

In addition, when driving a car, not only when driving in a city, but also when driving outside the vehicle, the car repeatedly accelerates and decelerates, and during acceleration, the operating state of the engine is as shown in Figure 1. Therefore, the operating range is above the running resistance characteristic i.

As mentioned above, when considering the high vehicle speed required on expressways and the power required to accelerate the car, and trying to drive with less fuel consumption, the boundaries a, b, c It is desirable to drive a car within the range enclosed by .

Note that boundary a indicates the characteristic of constant depression of the accelerator pedal while maintaining a state close to the minimum fuel efficiency. It is something to do. In addition, boundary b is, due to the above-mentioned high traction force,
While approaching the state as close to minimum fuel consumption as possible,
It means a state where the vehicle speed is accelerating, and for that purpose,
This indicates that it is better to reduce the depression amount a1 of the accelerator pedal as the engine rotational speed N increases. Furthermore, the boundary c is
As mentioned above, it shows the limit of the maximum speed that can be suppressed, and in cases where the maximum vehicle speed can be further reduced compared to driving on a highway, such as when driving in a city, the rotation speed number can be further reduced to the minimum fuel efficiency. It becomes possible to approach the area of Also, the boundary k indicates an additional range that provides a reference value when using the engine brake or when using the brake pedal.

The invention will be explained below with reference to illustrated embodiments.

FIG. 2 is a schematic electrical circuit diagram of an economical and fuel efficient driving instruction device that instructs the vehicle to drive within the range defined by boundaries a, b, c, and k in FIG. As shown in the figure, the first input terminal 1 is connected through a pulse voltage converter 2 and a characteristic converter 3, respectively.
It is connected to a first input of the comparator 4, and a second input terminal 5 is connected directly to the second input of the comparator 4. The pulse voltage converter 2 outputs a signal with a voltage level proportional to the number of pulses of the input AC pulse signal. The characteristic converter 3 has an input voltage V ₁ and an output voltage V ₂
The signal conversion is performed so that the relationship between the two gives a characteristic curve as shown in FIG. The output of the comparator 4 is connected to a green lamp 7 via a first amplifier 6a, and to a red lamp 9 via an inverter 8 and a second amplifier 6b, respectively.

In the above configuration, the first input terminal 1 has
The neutral section voltage of an alternator installed in a diesel engine such as a freight vehicle and driven by the diesel engine is supplied, while the second input terminal 5 is supplied with the neutral section voltage of an alternator that is mounted on a diesel engine such as a freight vehicle and driven by the diesel engine.
A voltage proportional to the amount of depression of the accelerator pedal in the engine is supplied. The above-mentioned neutral part voltage of the first input terminal 1 is an AC pulse proportional to the rotational speed of the engine, and the pulse is converted into a voltage level signal proportional to the number of pulses in the pulse/voltage converter 2. be done. The conversion characteristics of the characteristic converter 3 are preset to give an economical fuel consumption operating area surrounded by boundaries a, b, c, k in FIG. 1, and therefore boundaries a2, b2, c2 in FIG. ,k
2 correspond to boundaries a, b, c, and k in FIG. 1, respectively. Comparator 4 converts the converted output voltage of characteristic converter 3
V ₂ is compared with a voltage V ₃ corresponding to the amount of depression of the accelerator pedal supplied to the second input terminal 5, and when the former voltage V ₂ is greater than the latter voltage V ₃ , the voltage is output. give.

In the range where the input voltage V ₁ of the characteristic converter 3 corresponds to the low rotational speed of the engine, that is, in the range of characteristic a2 in FIG. 3, the converted output voltage V 3 of the characteristic converter ₃
indicates a constant value, and the comparator 4 gives a voltage output when the voltage V ₃ corresponding to the amount of depression of the accelerator pedal is smaller than the converted output voltage V ₂ in this range,
This state indicates that the engine is operating below the boundary a in FIG. 1, that is, in the economical and fuel efficient operating region. Also, the characteristic b2 in Fig. 3
In the range of , the converted output voltage V ₃ is accelerator
The comparator 4 also provides a voltage output when the voltage V ₂ corresponding to the amount of pedal depression is greater, and this condition indicates that the engine operation is at the boundary b in FIG.
It shows that it exists below the .

The characteristics c2 and k2 in Fig. 3 are the converted output voltage V ₂
However, when the engine speed N is greater than or equal to No,
This shows that the voltage value is always finite and close to zero. This finite voltage value close to zero is the reference value when using the engine brake or the brake pedal, and its magnitude is the same as the accelerator pedal.
When the brake is used as described above when the amount of pedal depression is zero, the comparator 4 determines that the voltage is greater than the zero voltage value corresponding to the amount of depression of the accelerator pedal supplied to the input terminal 5, and provides an output. It is a value of degree.
Due to the existence of such a boundary k2, when using the brakes when the driver has almost released the accelerator pedal, the engine operation is below the boundary k shown in FIG. Lighting is guaranteed. As a result, when the engine brake or the brake pedal is used in an emergency, the red lamp 9 will not light up even if the engine operation deviates from the economic and fuel efficiency operation area surrounded by boundaries a, b, and c. Therefore, there is no psychological turmoil caused to the driver, such as giving the driver the illusion that he or she must operate the accelerator pedal or change gears.

As is clear from the above description, when the comparator 4 provides a voltage output, the output is amplified by the amplifier 6a and the green lamp 7 is turned on. At this time,
The red lamp 9 is prevented from being lit by the inverter 8. Conversely, when the comparator 4 does not provide a voltage output, the green lamp 7 remains off, but the red lamp 9 is turned on as the output of the inverter 8 is amplified by the amplifier 6b. do. In other words, the economic fuel efficiency driving indicator shown in FIG. 2 displays a green light when the engine operation is in the range defined by the boundaries a, b, c, and k in FIG. Lamp 7 lights up, and in response,
When the engine is operating on or outside the boundaries a, b, c, k of FIG. 1, the red lamp 9 lights up.

FIG. 4 shows the characteristic converter 3 shown in FIG.
This is an example of a specific circuit configuration, and as described later, it is designed to correspond to various economic and fuel consumption characteristics determined by the purpose and type of the vehicle, or the type of internal combustion engine mounted on the vehicle. A characteristic converter is shown in which the boundaries can be set in various ways.

In the characteristic converter configured as shown in Fig. 4,
If the value of the resistor R ₁ is chosen to be large compared to the values of the resistors r ₁ , r ₂ , r ₃ , r ₄ , then the resistors r ₁ , r ₂ and the resistors r ₃ ,
The voltages E ₂ and E ₃ respectively related to r ₄ are operational amplifiers
Regardless of the output value of OP ₁ , it becomes a substantially constant value determined by the values of resistors r ₁ , r ₂ , r ₃ , and r ₄ . Voltage E ₃ is resistance
By adjusting the values of r ₃ and r ₄ by moving the slider, the voltage E ₂ can be changed by E ₂ = (r ₁ /r ₁ +r
₂ )・Given by E ₃ . Incidentally, in FIG. 4, Vcc indicates a constant voltage source.

The operational amplifier OP ₁ operates as a non-inverting amplifier with the diode D ₁ in a non-conducting state in the range E ₁ <E ₂ , and its amplification degree A ₁ is A ₁ =Eo/V ₁ =(1+R ₁ / R ₂ ). In addition, in the range of E ₁ ≧ E ₂ , diode D ₁ is in a conductive state,
Since the negative terminal input of the amplifier OP ₁ is a constant value E ₂ , the value of the output voltage Eo is practically infinite. Therefore,
The V ₁ -Eo characteristic of the operational amplifier OP ₁ is as shown in FIG. However, voltage Es ₁ is operational amplifier OP ₁
saturation voltage, and in the range of E ₁ <E ₂ , E ₁ ≈V ₁ .

The operational amplifier OP ₂ constitutes an inverting amplifier together with the resistors R ₃ and R ₄ , and its input/output characteristic, that is, the Eo-V ₂ ' characteristic is as shown in Fig. 6, in the range of Eo < E4, the output is The voltage V ₂ ′ becomes one value Es ₂ (saturation voltage of the operational amplifier OP ₂ ), and in the range Eo≧E4, the points E ₃ and E ₃
It becomes a straight line with a slope of (-R ₄ /R ₃ ). Note that the value of voltage E ₄ is given by the following equation.

E ₄ =E ₃ −R ₄ /R ₃ (Es ₂ −E ₃ ) of the first operational amplifier OP ₁ obtained in this way.
V ₁ −Eo characteristics and Eo− of the second operational amplifier OP ₂
V ₂ ′ characteristic and the seventh
It is possible to obtain the V ₁ −V ₂ ' characteristics shown in Figure (c). However, E _A and E _B are given by the following equations.

E _A =R ₂ /R ₁ +R ₂ {E ₃ −R ₄ /R ₃ (Es ₂ −E ₃
)} E _B = E ₃ + (E ₃ - E ₂ ) R ₄ /R ₃ - R ₄ R ₁ /R ₂
R ₃ E ₂ Furthermore, as shown in FIG. 4, the output voltage V ₂ ' of the second operational amplifier OP ₂ is combined with the tap voltage E ₄ of the voltage divider formed by resistors r ₅ and r ₆ . be done. At this time, the voltage E ₄ is set to a value close to zero as described above by adjusting the resistors r ₅ and r ₆ .

Therefore, the input/output characteristics of the characteristic converter shown in FIG. 4, that is, the V ₁ -V ₂ characteristics, become as shown in FIG. 8, which is the same as the conversion characteristic shown in FIG. 3. can be made to correspond to Therefore, E _A , E _B , E ₂ ,
Desired conversion characteristics can be obtained by appropriately setting the values of Es ₂ and E ₄ .

Next, the adjustable function of the characteristic converter shown in FIG. 4 will be explained.

In general, in the high fuel efficiency range shown in Figure 1, boundary b, for example, is determined by the shape of the isofuel consumption curve unique to tower-mounted engines, and it is also determined by the shape of the isofuel consumption curve unique to tower-mounted engines, and which is often accelerated and decelerated like a city bus. For vehicles that run at high speeds, it is preferable to set the boundary c to the left because the traveling speed is relatively low.On the other hand, for vehicles such as express buses, it is preferable to set the boundary c to the right as it is suitable for high-speed driving. . Therefore, it is extremely useful to configure a characteristic converter so that it can be applied to various types of vehicles through simple adjustment operations. According to the characteristic converter shown in FIG.
Of these, boundaries b and c can be made variable.

Specifically, as shown in FIG. 9, the voltage E ₃
By changing the voltage E 2 , we can move the boundary b to the boundary b′, while by changing the voltage E ₂ we can move the boundary b to the boundary c
can be moved to the boundary c′. If the amounts of change △E ₃ and △E ₂ in voltage E ₃ and voltage E ₂ are changed at a constant ratio, that is, △E ₂ /△E ₃ = r ₁ / r ₂ + r ₁ The resistance r at ₁ and r ₂ to appropriate values, the boundaries b and c can be moved in the horizontal axis direction by adjusting the resistances r ₃ and r ₄ with sliders, as shown in Figure 10. It can be moved.

The circuit configuration in Figure 11 consists of resistors r ₁ , r ₂ and resistors
This is an embodiment in which the voltages E ₂ and E ₃ can be adjusted separately and independently using two sliders associated with r ₃ and r ₄ respectively. In any case, whether to use one or two adjusting sliders is merely a matter of choice determined by manufacturing cost, difficulty of adjustment, shape of high fuel efficiency range, etc.

Note that the boundary a of the high fuel efficiency range shown in FIG.
It is also possible to make it variable, but this can be equivalently made variable by the load sensor side or the amount of depression of the accelerator pedal, so it is especially important to provide a characteristic converter with a variable function for boundary a. Not as good as that.

The driving operation of a vehicle equipped with the economic fuel efficiency driving instruction device described above in detail is as follows.

As mentioned above, a car generally detects danger ahead and constantly decelerates and accelerates repeatedly, and the state in which it accelerates from a decelerated state is explained in Figure 1. After deceleration, when the vehicle speed is in a steady state, the operating position of the engine is at point h on the running resistance characteristic i. When you step on the accelerator pedal from this state, the engine accelerates as shown by arrow d1,
At the same time, the vehicle is also accelerated. However, when the amount of depression of the accelerator pedal reaches the limit a, the red lamp 9 lights up to alert the driver, as explained in connection with FIG. As a result, when the driver slightly releases the pedal pedal, the red lamp 9 goes out and the green lamp 7 turns on. If the position of the pedal is maintained as it is, the engine rotational speed N will reach the boundary a
, and newly crosses the boundary b. As a result, the red lamp 9 lights up again, and the driver releases the accelerator pedal again until the red lamp 9 goes out. Such a state continues until the engine operation reaches the steady state operating point j on the running resistance characteristic i through the path shown by the arrow d1 to the arrow d.

In the above explanation, since the freight vehicle has a large cargo and a large body weight, the arrows d1 and d
The change in speed is gradual compared to that of a passenger car, and the driver has sufficient leeway to adjust the amount of depression of the accelerator pedal while paying attention to lamps 7 and 9.
Further, it goes without saying that the above explanation is applicable not only to freight cars but also to vehicles such as buses that transport a large number of passengers, and is also essentially applicable to general passenger cars.

In contrast to the above-mentioned acceleration driving operation, in the case of climbing a hill, the running resistance characteristic i in Fig. 1 moves upward, and acceleration when climbing a hill requires shifting from an over-top gear shift to an even lower gear ratio. The operating range of the engine also differs depending on the selection of the gear ratio. However, since the operating range can be indicated by blinking the lamps 7 and 9, the driver can select an appropriate gear ratio.

Furthermore, regarding the above-mentioned driving operation, when using the engine brake or operating the brake pedal,
The driver always releases the accelerator pedal almost all the time, in other words, the amount of accelerator pedal depression is almost zero, and the engine operation in this condition is below the boundary k in Figure 1. , and the green lamp 7 (FIG. 2) is lit.
Therefore, even if the engine operation is out of the economical and fuel efficiency operation area surrounded by the boundaries a, b, and c when the brakes are operated in a state of emergency, the red lamp 9 will not light up, and the driver will be informed. The system is designed to avoid psychological turmoil, such as creating the illusion that one must operate the accelerator pedal or shift gears while operating the brakes.

The characteristic conversion of the characteristic converter 3 shown in FIG.
As shown in Fig. 3, the input voltage V ₁ corresponding to the engine rotational speed is converted into the output voltage V ₂ , and this is converted into the voltage corresponding to the amount of depression of the accelerator pedal by the comparator 4. I'm comparing. This is done by giving the boundaries a, b, c, and k in FIG. 1 as a function of the rotational speed N, and considering the reference output signal thus given as a dimension of the amount of depression of the accelerator pedal. However, on the contrary, boundaries a, b,
It is also possible to give c and k as functions of the amount of accelerator pedal depression, consider the resulting reference output voltage as a dimension of engine rotational speed, and compare it with the voltage corresponding to the actual rotational speed N.

That is, if the conversion characteristics shown in Fig. 3 are expressed by the actual rotational speed N of the engine (corresponding to V ₁ ) and the reference value θi (corresponding to V ₂ ) for the amount of depression of the accelerator pedal, then the relationship θi= f(N) has a characteristic shown in FIG. 12, which is similar to FIG.
The boundaries a, b, c, k in the figure are given as a function of the accelerator pedal depression amount θi and the actual rotation speed N,
It is shown that the depression amount θi is given by a function f(N) of the rotational speed N.

Conversely, this means that the boundaries a, b,
The rotational speed Ni (reference value) on c and k is the accelerator
It becomes possible to give the function f(θ) of the pedal depression amount θ, and its conversion characteristic becomes as shown in FIG. Boundaries A ₁ , B1, C1 in Fig. 12,
K1 and boundaries A2, B2, C2, K2 in Figure 13
correspond to boundaries a, bc, and k in FIG. 1, respectively.

In this way, to actually perform the characteristic conversion shown in FIG. 13, input the detection signal of the accelerator pedal depression amount θ to the input terminal amount 1 in FIG.
The detection signal of the rotational speed N may be inputted to the input terminal 5, and the characteristic converter 3 may be given the conversion characteristic shown in FIG. 13, that is, the characteristic in which the output becomes Ni for the input θ.

To explain the operation in this case, in the characteristics K2 and C2 in the range where the accelerator pedal depression amount θ is small, the reference output of the characteristic converter 3 is a relatively high constant voltage, and the input terminal 5 is When the supplied rotational speed N detection signal is higher than the output voltage, the red lamp 9 lights up. The fact that the red lamp 9 lights up in the range of boundary K2 means that the engine rotational speed N has entered the critical speed from the engine's permissible rotational speed.・In addition to using the brake, it is also necessary to perform brake operation using the brake pedal in combination to reduce the engine speed. In the depressed state), the rotational speed N in FIG. 1 is greater than the preset maximum rotational speed No suitable for economical and fuel-efficient driving. accelerator·
When the pedal depression amount θ is within the range of characteristic B2, the output voltage of the characteristic converter 3 decreases as θ increases, and when the detection signal of the rotational speed N is higher than the output voltage, the red lamp 9 lights up. Furthermore, when the accelerator pedal depression amount θ exceeds the range of characteristic A2, the output of the characteristic converter 3 corresponding to the reference rotational speed Ni always becomes zero, and as a result, the output of the characteristic converter 3 corresponding to the reference rotation speed Ni becomes zero.
The finite voltage value supplied to the output will always be higher than the output and the red lamp 9 will light up.

As is clear from the above explanation, the comparison by the comparator 4 in FIG. It is easy to understand that it is sufficient if the amount of depression is compared with the other one.

According to the economic fuel efficiency driving instruction device of the present invention as described above, when the operating state of the engine deviates from the economic fuel efficiency operating range, a warning lamp is lit to call the driver's attention. The engine is operated within the above-mentioned range, and as a result, the vehicle can repeatedly accelerate while approaching the minimum fuel efficiency operation. Therefore, fuel consumption can be reduced to the extent possible while effectively enabling high-speed running and repeated acceleration and deceleration required of the vehicle.

Further, according to the present invention, the driving operation is merely to judge the simple alternating flashing of the green lamp 7 and the red lamp 9 and simply change the amount of depression of the accelerator pedal, especially in normal driving operations. It does not require any new driving skills in addition to the previous driving skills.

Furthermore, since the configuration of the present invention is an extremely simple circuit configuration in which the characteristics of the first detection signal of the two types of detection signals are converted and compared with the second detection signal, the manufacturing cost is low. Since it is inexpensive and the characteristic converter has an adjustable function, it can be applied to various vehicles.

Further, according to the present invention, since the red lamp is prevented from turning on when the brake is used, safe driving can be ensured without causing psychological upset to the driver.

Furthermore, according to the present invention, the voltage of the neutral part of the alternator is used to detect the rotational speed of the internal combustion engine, so expensive parts such as an electromagnetic pickup are not required. This reduces the installation cost of the entire device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the equal fuel consumption curve of a typical diesel engine and its operating characteristics. FIG. 2 is an electrical circuit diagram showing an embodiment of the economic fuel consumption driving instruction device of the present invention. FIG. 3 is a diagram showing the conversion characteristics of the characteristic converter shown in FIG. 2. FIG. 4 is a detailed electrical circuit diagram of the characteristic converter shown in FIG. 5, 6, 7, and 8 are diagrams showing the operating characteristics of the characteristic converter shown in FIG. 4. 9 and 10 are diagrams showing variable characteristics based on the adjustable function of the characteristic converter shown in FIG. 4. FIG. 11 is an electrical circuit diagram showing another embodiment of the adjustable section of the characteristic converter shown in FIG. 4. FIG. 12 shows the boundaries a, b, and
When c and k are given as the amount of depression of the accelerator pedal, this is a diagram showing a conversion characteristic given as a function of the actual rotational speed of the engine. FIG. 13 is a diagram showing a conversion characteristic in which boundaries a, b, c, and k are similarly given as rotational speeds and are given as a function of the actual amount of depression of the accelerator pedal. (Description of symbols) 1, 5: Input terminal, 2: Pulse terminal
Voltage converter, 3: Characteristics converter, 4: Comparator, 6
a, 6b: amplifier, 7, 9: lamp, 8: inverter.

Claims (1)

[Claims] 1. (a) A detection signal corresponding to the rotational speed of the internal combustion engine is input, and the output torque of the internal combustion engine is in a functional relationship with the detection signal and indicates an economical and fuel consumption operating region of the internal combustion engine. The characteristic converter outputs an output signal corresponding to (a) the input, and the functional relationship is based on a predetermined equal fuel efficiency curve in a coordinate system given by the input and the output. When is smaller than the first predetermined value, the output is given at a constant value; (b)
When the input is a value greater than the first predetermined value and smaller than the second predetermined value which is greater than the first predetermined value, the output increases to the constant value as the input increases. (c) when the input is at the second expected value, the output is given as a value close to zero that decreases from the gradually decreasing value; (d) the input is a value greater than the second predetermined value and smaller than a third predetermined value larger than the second predetermined value, the output is given at a value close to the zero, A value close to defines a reference value with the accelerator pedal released and the brake applied; , a second boundary given by the gradually decreasing value, and a third boundary given by a decrease from the gradually decreasing value to the value close to zero,
a fourth boundary given by a value close to zero; and (b) the output signal and a detection signal corresponding to the amount of depression of the accelerator pedal. An economic fuel efficiency driving instruction device comprising: a comparator for comparing the values of the fuel and the fuel; and (c) a display that is activated by an output signal of the comparator. 2. A patent claim characterized in that at least one of the first, second, and third boundaries provided by the characteristic converter is adjustable so as to move parallel to the coordinate axis of the coordinate system. The economical fuel consumption driving instruction device according to item 1. 3. The economic fuel consumption driving instruction according to claim 1 or 2, wherein the detection signal corresponding to the rotational speed is a neutral voltage of an alternator driven by the internal combustion engine. Device. 4. The economic fuel efficiency driving instruction device according to any one of claims 1 to 3, wherein the internal combustion engine is a diesel engine installed in a freight vehicle.