JP2012031824A - Device for evaluating fuel consumption rate of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To objectively evaluate a fuel cost of a vehicle by the absolute standard irrespective of a gross vehicle weight or engine displacement.SOLUTION: A fuel consumption rate calculation unit 24 divides a fuel consumption amount mthat is an integrated value of a fuel injection amount Ti during travel distance calculation calculated by a fuel consumption amount calculation unit 22 by a travel distance L calculated by a travel distance calculation unit 21 to calculate a fuel consumption rate Mf per unit travel distance. A required work amount calculation unit 25 calculates a required work amount We based on a square root of a product of a gross vehicle weight M calculated by a gross vehicle weight calculation unit 23 and an engine displacement Vd. A fuel consumption rate evaluation value calculation unit 26 divides the fuel consumption rate Mf by the required work amount We to calculate a fuel consumption rate evaluation value f. The fuel consumption rate evaluation value f is an inclination of a straight line connecting a coordinate point (Mf, We) specified by the fuel consumption rate Mf of ordinate and the required work amount We of abscissa and the origin, and indicates the required fuel cost per unit work.

Description

  The present invention relates to a vehicle fuel consumption rate evaluation apparatus that can objectively evaluate the fuel consumption of any vehicle on an absolute basis.

  Ascertaining the distance traveled per unit fuel (usually 1 [L (liter))], that is, the fuel consumption rate (hereinafter abbreviated as “fuel consumption”), is a means to reduce vehicle running costs. Not only important, but also extremely important from the viewpoint of environmental protection.

  In particular, in the case of vehicles such as route buses that regularly travel in a certain fixed section and trucks that deliver and operate between bases, the fuel efficiency greatly affects the overall fare and logistics costs. The major issue is whether to drive the vehicle.

  However, since fuel efficiency depends on the weight (total vehicle weight) and displacement, it is not preferable to evaluate the fuel efficiency based on the driver's driving skill alone. It is objective after considering various driving conditions. It is desirable to evaluate to.

  For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2001-349774), the fuel consumption rate of a vehicle, various fixed data relating to the vehicle, and flow data such as the total vehicle weight are digitized, and a part or all of them is added A technique is disclosed in which an evaluation value related to the vehicle is calculated based on the added numerical value, and the evaluation value is displayed on a display device.

  According to the technique disclosed in this document, since the value taking into account different fixed data and flow data for each vehicle is calculated, the fuel efficiency calculated for each vehicle can be rationally evaluated.

Japanese Patent Laid-Open No. 2001-349774

  However, in the technique disclosed in the above-described literature, since different evaluation values are calculated depending on the total vehicle weight and the displacement, it may be possible to optimize the evaluation between the same vehicles.

  However, a route bus operating company and a trucking company often have a plurality of kitchens with different vehicle types and displacements, and they are always operated. In the technique disclosed in the cited document 1, these various types are used. Regardless of the total weight or displacement of the vehicle, the fuel efficiency of the vehicle cannot be objectively evaluated on an absolute basis, which is inconvenient.

  In view of the above circumstances, the present invention is a vehicle fuel consumption rate evaluation apparatus that can objectively evaluate the fuel consumption of various vehicles based on absolute standards regardless of the total vehicle weight and displacement, and is easy to use. The purpose is to provide.

  In order to achieve the above object, a fuel consumption rate evaluation apparatus for a vehicle according to the present invention includes a travel distance calculating means for measuring a predetermined section travel distance of the vehicle, and measuring the section travel distance with the travel distance calculating means. A fuel consumption amount calculating means for calculating the fuel consumption amount by integrating the fuel injection amount supplied from the injector to the engine, a vehicle total weight calculating means for determining the total weight of the vehicle, and the fuel consumption amount by the section travel distance. Fuel consumption rate calculating means for calculating a fuel consumption rate by dividing, and required work amount calculating means for obtaining a required work amount of the engine required for traveling from a square root of a product of the total vehicle weight and the engine displacement A fuel consumption rate evaluation value calculating means for obtaining a fuel consumption rate evaluation value by dividing the fuel consumption rate by the required work amount, and a display means for displaying the fuel consumption rate evaluation value. That.

  According to the present invention, since the fuel consumption rate is divided by the required work amount calculated from the square root of the product of the total vehicle weight and the engine displacement, the fuel consumption rate evaluation value is obtained. By using the evaluation value, the fuel consumption of various vehicles can be objectively evaluated based on absolute standards regardless of the total vehicle weight and the displacement.

Schematic configuration diagram of main parts of a vehicle control system including a fuel consumption rate evaluation device Functional block diagram of the fuel consumption rate evaluation device Chart showing fuel consumption rate evaluation coefficient

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a main configuration of a vehicle control system mounted on a vehicle such as a passenger car, a truck, or a bus. The vehicle control system includes a control device that controls a vehicle represented by an engine control device (E / G_ECU) 1, a fuel consumption rate evaluation device (evaluation_ECU) 2, and a display device 3 as a display means. These are connected so as to be able to communicate with each other through an in-vehicle communication line 4 such as CAN (Controller Area Network) communication. The evaluation_ECU 2 is a processing device that is not directly related to the vehicle control but is necessary for grasping the traveling state of the vehicle. Further, in the figure, for the sake of convenience, only a processing device that acquires parameters relating to the fuel consumption rate evaluation employed in the present embodiment is shown.

  Each of the ECUs 1 and 2 is mainly composed of a microcomputer, and has a known non-volatile storage means such as a CPU, ROM, RAM, and EEPROM. In this embodiment, a monitor of a car navigation device is adopted as the display device 3, but this display device 3 can display evaluation contents such as a 7-segment display and a dot matrix LED display composed of a plurality of digits. Anything is acceptable.

  The E / G_ECU 1 controls the entire operating state of the engine, and sensors for detecting engine operating state parameters such as a rotational speed sensor 7 for detecting the engine rotational speed are connected to the input side. Further, an actuator for controlling engine driving such as an injector (not shown) for supplying a predetermined amount of fuel to the combustion chamber is connected to the output side of the E / G_ECU 1. The E / G_ECU 1 sets a fuel injection timing for the injector and a fuel injection amount (fuel injection pulse width) Ti to be supplied from the injector to each cylinder based on a parameter indicating the engine operating state detected by each sensor.

  The evaluation_ECU 2 sets an evaluation value for evaluating the fuel consumption of the vehicle based on an absolute reference, and a vehicle speed sensor 5 for detecting the vehicle speed and a vehicle weight sensor 6 for detecting the vehicle weight are connected to the input side. ing. The basic concept of the evaluation value of the fuel consumption obtained by this evaluation_ECU 2 is shown below.

If the net average effective pressure of the engine is bmep [kg / m ² ] and the displacement is Vd [m ³ ],
The work Wb ([kg / m ² · m ³ ] = [kgm]) for one engine cycle is
Wb = bmep ・ Vd
It becomes.

If the engine speed is N [rev / sec] and nR (constant: 2 for 4 cycles, 1 for 2 cycles), the net work (output) Pb [kgm / sec] per unit time of the engine is
Pb = Wb · N / nR
= N / nR ・ bmep ・ Vd (1)
Thus, it can be seen that the net work Pb per engine unit time is proportional to the displacement Vd (Pb∝Vd (2)).

On the other hand, when the vehicle speed is not so high, the work required for running the vehicle can be expressed as the sum of the constant speed running resistance work and the acceleration work, omitting the work against the air resistance during running. In this case, if the total vehicle weight is M, the rolling resistance coefficient is CR, the gravitational acceleration is g, the vehicle acceleration is α, and the travel distance per unit time is L [m / sec], the travel work Pr [kgm / sec]
Pr = (M · CR · g) · L + (M · α) · L
= ((CR · g) + α) · L · M
It becomes. Accordingly, it can be seen that the driving work Pr per unit time of the vehicle is proportional to the total weight M of the vehicle (Pr∝M).

On the other hand, if the fuel consumption of one engine cycle is m _f [g], this fuel consumption m _f can be expressed using the net fuel consumption rate bsfc [g / kWs].
m _f = bsfc · Wb
The fuel consumption rate Mf [g / s] per unit time is
_{Mf = m f · N / nR} = N / nR · bsfc · (bmep · Vd)
It becomes. Therefore, it can be seen that the fuel consumption rate Mf per unit time is proportional to the displacement Vd (Mf∝Vd (3)).

From equation (1),
Mf = bsfc · Pb (4)
It becomes. Here, since the driving work Pr per unit time of the vehicle is supplied from the engine output and is Pr∝Pb, the fuel consumption rate Mf per unit time is
Mf = bsfc ・ Pb∝bsfc ・ Pr∝M
Thus, it can be seen that the fuel consumption rate Mf is proportional to the total weight M of the vehicle (Mf∝M (5)).

And taking the square root of the product of both sides of (3) and (5),
Mf∝ (Vd ・ M) ^1/2 (6)
Thus, it can be seen that the fuel consumption rate Mf per unit time is proportional to the square root of the product of the engine displacement Vd and the total vehicle weight M.

  In other words, the work W necessary for traveling is roughly proportional to the total weight M of the vehicle, and the net work (output) of the engine that generates the work W necessary for traveling is proportional to the displacement Vd. From this, it can be said that the work W required for traveling is proportional to the square root of the product of the total vehicle weight M and the displacement Vd. On the other hand, the ratio between the work W necessary for traveling and the fuel consumption rate Mf necessary for traveling can be referred to as the fuel consumption rate per unit work.

  Therefore, in the present embodiment, the fuel consumption rate is obtained from the fuel consumption amount at the predetermined travel distance L, and this fuel consumption rate is divided by the required work amount obtained by the square root of the product of the exhaust amount Vd and the total vehicle weight M. Thus, the fuel consumption rate per unit work is calculated, and this is set as the fuel consumption rate evaluation value (fuel consumption evaluation value). Since this fuel efficiency evaluation value is a value per unit work, the fuel efficiency (conversion efficiency from fuel supplied to the engine to work) possessed by the vehicle is absolute regardless of the total vehicle weight M and the displacement Vd. Can be set as any value.

  In the evaluation_ECU 2, based on the above-described idea, from the fuel injection amount Ti obtained by the E / G_ECU 1, the vehicle speed S [m / sec] detected by the vehicle speed sensor 5, and the vehicle weight Mt [Kg] detected by the vehicle weight sensor 6, A fuel efficiency evaluation value is set and stored in the non-volatile storage means and displayed on the display device 3.

  FIG. 2 represents the arithmetic program executed by the evaluation_ECU 2 as a functional block. As a function for calculating a fuel efficiency evaluation value executed by the evaluation_ECU 2, the present embodiment is a travel distance calculation unit 21 as a travel distance calculation unit, a fuel consumption calculation unit 22 as a fuel consumption calculation unit, and a vehicle total weight calculation. Vehicle total weight calculation unit 23 as means, fuel consumption rate calculation unit 24 as fuel consumption rate calculation means, required work amount calculation unit 25 as required work amount calculation means, fuel consumption rate as fuel consumption rate evaluation value calculation means An evaluation value calculation unit 26, a fixed data storage unit 27, and a data storage unit 28 are included. The fixed data storage unit 27 stores net weight (NET) data and displacement data of the vehicle, and the data storage unit 28 includes various types of IC memory such as a hard disk and flash memory that can be updated and stored. In this storage medium, the history of various data obtained by the evaluation_ECU 2 such as the fuel consumption rate Mf, the required work amount We described later, and the fuel consumption rate evaluation value f described later is stored together with date information. Has been.

  The travel distance calculation unit 21 calculates a travel distance (section travel distance) L [m] of a preset section based on the vehicle speed S [m / sec] detected by the vehicle speed sensor 5. The vehicle speed sensor 5 detects the vehicle speed based on the average value of the wheel speeds detected by the wheel speed sensors disposed on the four wheels, for example, in addition to the vehicle speed obtained by detecting the rotation speed of the transmission output shaft. It may be a thing.

  Further, the section in which the section travel distance L is measured may be a continuous section in which preset operation conditions are satisfied, or one trip (period from one engine start to stop). ) May be set as the travel section. Or you may set the area until fuel is supplied to a fuel tank as a driving | running | working area. Furthermore, as will be described later, an instantaneous section travel distance (for example, 0.5 to 1 [m]) close to 0 [m] may be used as the section travel distance L. In this case, the section travel distance may be sequentially updated from when the driver turns on the ignition switch until the ignition switch is turned off. By sequentially updating the section travel distance, the driver can be notified of a fuel efficiency evaluation value f described later in real time.

The fuel consumption amount calculation unit 22 calculates the fuel consumption amount m _f [g] by integrating the fuel injection amount Ti calculated by the E / G_ECU 1 while the travel distance calculation unit 21 measures the section travel distance L. .

  The vehicle gross weight calculation unit 23 calculates the vehicle gross weight M by adding the vehicle weight Mt detected by the vehicle weight sensor 6 and the net weight (NET) Mn of the vehicle stored in the fixed data storage unit 27. (M ← Mn + Mt). As the in-vehicle weight sensor 6, for example, a sensor that detects the load weight of the vehicle by detecting the stroke amount of the left and right rear suspensions is known.

The fuel consumption rate calculation unit 24 divides the fuel consumption amount m _f [g] obtained by the fuel consumption amount calculation unit 22 by the section travel distance L [m] calculated by the travel distance calculation unit 21 to obtain a unit travel distance. It calculates fuel consumption rate per the (fuel) Mf [g / m] ( Mf ← m f / L). In this case, the section travel distance L is a combination of a relatively long section travel distance set in advance and an instantaneous section travel distance (for example, 0.5 to 1 [m]) close to 0 [m]. The fuel consumption [g / m] of both may be calculated at all times.

  By the way, the fuel consumption rate Mf can be expressed by the amount of fuel consumed by the engine when moving in a predetermined distance (mode running) over a predetermined distance. In cruise traveling, the distance traveled by the vehicle is approximately proportional to the travel time, so the fuel consumption per unit time and the fuel consumption per unit distance are approximately proportional. Therefore, the fuel efficiency Mf [g / m] may be divided by the time when the section travel distance L is measured to obtain the fuel efficiency Mf [g / sec] per unit time.

The necessary work amount calculation unit 25 is based on the total vehicle weight M obtained by the total vehicle weight calculation unit 23 and the engine displacement Vd stored in the fixed data storage unit 27 and mounted on the vehicle. The required work amount We is obtained from the square root of the product of (We ← (M · Vd) ^1/2 ).

  As described above, the work W necessary for traveling is proportional to the total weight M of the vehicle, and the net work (output) of the engine that generates the work W necessary for traveling is proportional to the displacement Vd. The work amount (required work amount) We of the engine is proportional to the square root of the product of the total vehicle weight M and the displacement Vd.

  The fuel consumption rate evaluation value calculation unit 26 calculates the fuel consumption evaluation value f by dividing the fuel consumption Mf obtained by the fuel consumption rate calculation unit 24 by the required work amount We obtained by the required work amount calculation unit 25. Therefore, as shown in FIG. 3, the fuel efficiency evaluation value f is a linear slope connecting the coordinate point (Mf, We) and the origin in the graph where the vertical axis represents the fuel efficiency Mf and the horizontal axis represents the required work amount We. (Mf = f · We).

  In the graph shown in FIG. 3 described above, the horizontal axis represents the required work amount We, the vertical axis represents the fuel consumption Mf during 100 [Km] traveling, and a certain setting is made for each driving method (engine vehicle and hybrid vehicle in the figure). The relationship between the fuel efficiency Mf and the required work amount We in mode travel (for example, 10.15 mode travel) is examined and plotted. As a result, it can be seen that the plotted coordinate points are arranged on a substantially straight line for each driving method. Therefore, the slope of a straight line (solid line for engine vehicles, wavy line for hybrid vehicles) represented by a linear approximation equation obtained by the least square method or the like for each driving method based on each blotted coordinate point is an average for each driving method. Expressed as evaluation values (average evaluation values) Af1 and Af2. The average evaluation values Af1 and Af2 may be calculated from the average value of the linear gradient f connecting the plotted coordinate points (Mf, We) and the origin.

  As can be seen from this graph, the slope of the straight line connecting the plotted coordinate points and the origin, which is the fuel consumption rate evaluation value f, indicates the fuel consumption required per unit work, and the total vehicle weight M and engine displacement Vd. It is an absolute evaluation value that does not affect From this, by examining the relationship between the required work amount We and the fuel consumption Mf in a vehicle (for example, a commuter vehicle), a truck (for example, a truck for delivery between bases), and a route bus that travels in a certain fixed section. The fuel efficiency Mf can be analyzed more accurately. In other words, the fuel efficiency evaluation value f, which is a slope of the linear expression connecting the plotted coordinate points (We, Mf) and the origin, indicates that the smaller the value, in other words, the smaller the slope, the better the fuel efficiency.

  In this case, the fuel efficiency Mf measured in the mode driving and the fuel efficiency Mf in the actual road driving are different even in the same vehicle type, so the comparison conditions are not exactly the same. By adding various flow data such as / OFF and road surface gradient as correction terms as appropriate, it is possible to objectively determine whether the fuel efficiency Mf is good or bad based on data detected during actual road travel, which is easy to use. Also, for example, the coordinate points plotted at the time of the current run and the origin are connected with reference to the slope of the average linear expression (average evaluation values Af1, Af2) for each driving method indicated by a solid line or a wavy line in FIG. Comparing the slopes of the linear formulas (fuel efficiency evaluation value f) makes it possible to more reasonably judge whether the fuel efficiency is good or bad.

  The fuel consumption evaluation value f obtained by the fuel consumption rate evaluation value calculation unit 26 is output to the display device. Further, the required work amount We, the fuel consumption Mf, and the fuel consumption evaluation value f calculated this time are data together with the measurement date information. It is stored in the storage unit 28.

  When the display device uses a monitor such as a car navigation device, for example, a graph showing the fuel consumption Mf on the vertical axis and the required work amount We on the horizontal axis is displayed on the monitor. Then, on this monitor, the least squares method or the plotted coordinate points (for example, the latest 10 past history points in the same travel section) from the history of a plurality of coordinate points (We, Mf) plotted in the past on the vehicle type. (We, Mf) and an approximate straight line passing through the origin obtained by an average value of the inclination of the straight line connecting the origin and the like are displayed. Furthermore, a straight line connecting the coordinate point plotted this time and the origin is displayed with respect to the approximate straight line. Then, the driver compares the slopes (fuel efficiency evaluation values) of both straight lines to determine whether the fuel efficiency of the current driving is good or bad.

  If the display device is a 7-segment display or a dot matrix LED display consisting of a plurality of digits, the fuel efficiency evaluation value f and the average evaluation value Af1 or Af2 are alternately displayed at a certain time. Display in two rows. Then, the driver compares the fuel efficiency evaluation value f displayed on the display and the average evaluation value Af1 or Af2 to determine whether the fuel efficiency is good or bad. In this case, the difference between the fuel efficiency evaluation value f and the average evaluation value Af1 or Af2 may be displayed on the display, and the fuel efficiency may be recognized from the difference.

  In this case, the fuel efficiency evaluation value f may be displayed on the display device from when the driver turns on the ignition switch. At that time, by sequentially updating the section travel distance L in one trip until the ignition switch is turned off, the fuel efficiency evaluation value f can be notified to the driver in real time.

  Further, by reading out and analyzing the data stored in the data storage unit 28, based on this data, the driving skill of the driver is not affected by fluctuations in the weight of the vehicle or the magnitude of the displacement of the vehicle. Can be objectively evaluated based on absolute standards. Therefore, the fuel consumption rate evaluation apparatus 2 according to the present embodiment is incorporated in, for example, a truck owned by a trucking company that delivers between bases or a route bus owned by a route bus operating company, and is stored in the data storage unit 28. The driver's driving skill can be accurately evaluated by reading and analyzing the fuel efficiency evaluation value f that is being used by the in-house management system. Moreover, if the fuel consumption rate evaluation apparatus 2 according to the present embodiment is incorporated in a rental car having a different vehicle type, it can be utilized as information for encouraging the driver to drive economically, and in the same manner as described above, By reading, it is possible to objectively evaluate the fuel consumption between vehicle types. Furthermore, since this fuel consumption rate evaluation apparatus 2 can be incorporated into an existing vehicle as an aftermarket product, high versatility can be obtained.

  Note that the present invention is not limited to the above-described embodiment. For example, the evaluation target classification is not limited to an engine vehicle and a hybrid vehicle. For example, a continuously variable transmission-equipped vehicle, an automatic transmission-equipped vehicle, a manual You may classify | categorize by the fuel to be used, such as the kind of transmission mounted in vehicles, such as a transmission vehicle, a gasoline vehicle, a diesel vehicle, etc., and you may classify | categorize by these combination.

1 ... Engine,
3 ... display device,
21 ... mileage calculation unit,
22 ... Fuel consumption calculation unit,
23 ... Total vehicle weight calculation unit,
24 ... Fuel consumption rate calculation unit,
25 ... Required work calculation unit,
26 ... Fuel consumption rate evaluation value calculation unit,
Af1, Af2 ... average evaluation value,
f ... Fuel consumption rate evaluation value,
L: Section mileage,
M: Gross vehicle weight,
Mf: Fuel consumption rate,
mf ... fuel consumption Ti ... fuel injection amount,
Vd: engine displacement,
We ... Required work,

Claims (4)

Mileage calculating means for measuring a predetermined section mileage of the vehicle;
Fuel consumption calculation means for integrating the fuel injection amount supplied from the injector to the engine while measuring the section travel distance by the travel distance calculation means;
Vehicle total weight calculating means for determining the total weight of the vehicle;
Fuel consumption rate calculating means for calculating the fuel consumption rate by dividing the fuel consumption amount by the section travel distance;
A required work calculating means for determining a required work of the engine required for traveling from the square root of the product of the total vehicle weight and the engine displacement;
A fuel consumption rate evaluation value calculating means for obtaining a fuel consumption rate evaluation value by dividing the fuel consumption rate by the required work amount;
A fuel consumption rate evaluation apparatus for a vehicle, comprising: display means for displaying the fuel consumption rate evaluation value. The fuel consumption rate calculation means sets the travel distance from the time when the ignition switch is turned on to the local point as the section travel distance, and divides the fuel consumption amount in the section travel distance by the section travel distance to thereby calculate the fuel consumption rate. The fuel consumption rate evaluation apparatus for a vehicle according to claim 1, wherein: The fuel consumption rate calculation means sets the travel distance close to 0 meter as the travel distance, divides the fuel consumption amount in the travel distance by the travel distance, and instantaneously consumes the fuel consumption rate. The fuel consumption rate evaluation apparatus for a vehicle according to claim 1, wherein: The display means displays a comparison result between an average value of a plurality of past fuel consumption rate evaluation values and the fuel consumption rate evaluation value obtained this time. The fuel consumption rate evaluation apparatus for vehicles described in 1.

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