KR20030095030A - a method for calculating fuel economy of hybrid electric vehicle - Google Patents

Abstract

PURPOSE: A method is provided to evaluate the actual fuel efficiency of hybrid vehicle through a single test by calculating the total fuel efficiency in consideration of fuel consumption of engine and energy consumption of electrical system. CONSTITUTION: A method comprises a step(S100 to S130) of taking, as an input, a hybrid structure, engine efficiency and a motor efficiency, and dividing operation sections in accordance with the rate of engine operation and motor operation; a step(S170 to S200) of repeatedly calculating equivalence factors for converting an electrical energy into a fuel in each operating section; a step(S240) of calculating an average of equivalence factors by obtaining the representative value of the equivalent factors, and calculating a fuel consumption of the vehicle from the calculated average; and a step(S250) of calculating a fuel efficiency by dividing the fuel consumption by the travel distance.

Description

{A method for calculating fuel economy of hybrid electric vehicle}

The present invention relates to an electric vehicle, and more particularly, to a method of calculating the actual fuel efficiency of a hybrid vehicle for calculating the actual fuel efficiency of a hybrid electric vehicle running according to the selective driving of a gasoline engine and an electric motor. will be.

A conventional vehicle is a vehicle that is driven by driving a gasoline or diesel engine as shown in FIG. 1, and the electric vehicle is driven by the operation of an electric motor by electricity due to an increase in environmental pollution caused by an automobile using an internal combustion engine. Cars are being developed.

Internal combustion engine cars have a disadvantage in that a lot of exhaust gas to increase the environmental pollution, electric vehicles have the advantage of preventing environmental pollution, but there is a disadvantage that can not run for a long time because it is driven by a battery.

In order to solve the disadvantages of the internal combustion engine car and the electric vehicle, a hybrid electric vehicle is a vehicle that combines the functions of the internal combustion engine vehicle and the electric vehicle.

The hybrid electric vehicle is a vehicle in which a general internal combustion engine (hereinafter referred to as an engine) driving function and an electric motor driving function are inherent. In other words, a hybrid electric vehicle refers to a vehicle that can be driven by a general engine vehicle or an electric vehicle as needed.

Since a hybrid electric vehicle is composed of components different from existing engine vehicles and electric vehicles such as engines, batteries, and electric motors, various driving methods such as engine and motor control according to battery power conditions are required when driving a vehicle.

The driving method of the hybrid electric vehicle requires proper control of the engine and the electric system according to the motor driving power, the regenerative power, the state over charge (SOC), the voltage and current of the DC link, the speed of the vehicle, and the like.

The hybrid vehicle has a hybrid emission vehicle (HEV) mode and a Zero Emission Vechicle (ZEV) mode. The HEV mode is a mode in which a vehicle is driven by driving an engine and an electric motor. In this state, the vehicle runs under power supply by the battery.

As described above, the method for evaluating fuel efficiency in a hybrid vehicle that is driven in the HEV mode and the ZEV mode has conventionally used a method of dividing the driving distance by the consumption of fuel of the engine.

2 shows the energy flow in the hybrid vehicle at the time of charging / discharging.

During charging, the power output from the engine is used to drive some of the vehicle and to charge the electric motor. When discharging, the vehicle is driven by adding electric power to the electric motor and the engine.

However, conventionally, only the amount of fuel consumed in the engine is considered, and the energy charged or discharged in the battery is not considered.

In addition, the Zero Delta SOC calibration method, which is proposed to consider the consumption of electrical energy, involves the problem that numerous iterative calculations and tests are required to find the starting SOC point for the SOC calibration.

Accordingly, an object of the present invention is to solve the above problems, the electric energy consumed while driving in a hybrid vehicle must be replenished by using the power of the engine, and thus the amount of electric energy consumed in the engine consumed when recharging it. As can be defined as the fuel consumption of the, to provide a fuel consumption calculation method of the hybrid vehicle that can calculate the fuel economy of the entire vehicle considering both the engine fuel consumption and the energy consumption of the electrical system.

1 is a flow chart of fuel consumption of a gasoline vehicle,

2 is a flow chart of fuel and energy consumption of a hybrid vehicle,

3 is a block diagram of an apparatus for calculating fuel economy of a hybrid vehicle according to the present invention;

4 is a flowchart illustrating a method for calculating fuel economy of a hybrid vehicle according to the present invention.

<Description of Symbols for Main Parts of Drawings>

10 electric system 11 battery 12 electric motor

20 engine system 21 gasoline fuel 22 engine

30: transmission 100: data input unit

110: hybrid structure input unit 120: engine efficiency data input unit

130: motor efficiency data input unit 140: battery efficiency data input unit

150: engine torque input unit 160: engine speed input unit

200: HVC

The present invention for achieving the above object,

A fuel economy calculation method for a hybrid vehicle, comprising: dividing an operation section according to a ratio of engine driving and motor driving by receiving a hybrid structure, engine efficiency, and motor efficiency;

Iteratively calculating an equivalent coefficient for converting electrical energy in each operation section divided in the step into fuel;

Calculating an average of the equivalent coefficients by calculating representative values of the equivalent coefficients repeatedly calculated in the above steps, and calculating fuel consumption of the vehicle using the averages of the equivalent coefficients;

The fuel consumption is calculated by dividing the fuel consumption calculated in the above step by the mileage.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a block diagram of the fuel economy calculation device configuration of a hybrid vehicle according to the present invention, Figure 4 is a flow chart of the fuel economy calculation method operation of the hybrid vehicle applied to the present invention.

As shown in FIG. 3, the fuel efficiency calculator of a hybrid vehicle includes data for inputting data such as engine torque and engine speed that vary according to a change in operating state of a vehicle, a structure of an hybrid vehicle, engine efficiency, electric motor efficiency, and battery efficiency. An input unit 100;

The engine input and engine speed and the structure of the hybrid vehicle, the engine efficiency, the motor efficiency and the battery efficiency are input from the data input unit 100, and the electrical energy consumed in the electrical system is converted into fuel consumption, and then the engine is calculated. The fuel consumption of the system and the value calculated after the calculation is divided by the mileage is composed of the HVC (200) for calculating the fuel economy of the hybrid vehicle.

The data input unit 100 includes a hybrid input unit 110 for inputting a current hybrid structure;

An engine efficiency data input unit 120 for inputting engine efficiency data of the vehicle engine;

A motor efficiency data input unit 130 for inputting motor efficiency data of the vehicle electrical system;

A battery efficiency data input unit 140 for inputting efficiency data of a current vehicle battery;

An engine torque input unit 150 for inputting a change region of the torque of the engine that varies according to a change in the vehicle operating state;

It consists of an engine speed input unit 160 for inputting a change region of the engine speed that is variable according to the change in the driving state of the vehicle.

The fuel consumption calculation method of the hybrid vehicle having the above-described configuration will be described with reference to FIGS. 2, 3, and 4.

FIG. 2 is a diagram illustrating an energy consumption state of a hybrid vehicle, wherein the electric system 10 driving the vehicle shaft 30 by the force of the electric motor 12 driven by using the battery 11 energy, and gasoline It consists of the engine system 20 which burns the fuel 21 and drives the drive shaft 30 by the rotational force of the engine 22.

In the energy consumption of the hybrid vehicle, the electric energy consumed while driving must eventually be replenished using the power of the engine, and thus the electric energy consumption can be defined as the fuel consumption in the engine consumed when recharging it.

When the amount of fuel consumed in the engine 22 is defined as fc_e and the equivalent fuel consumed by converting the electrical energy consumed in the electric motor 12 into fuel is fc_m, the equivalent fuel consumption fc_m consumed in the electric motor 12 is consumed as electrical energy. It can be defined as the fuel consumption of the engine used when replenishing (ec_m).

Accordingly, as shown in FIG. 3, the HVC 200 receives a hybrid structure, an engine efficiency, and an electric motor efficiency for a current vehicle stored in a memory, and the efficiency of a battery used in an electric motor. The engine torque and the engine speed according to the output of the engine are input, and the power distribution ratio PSR is calculated by dividing the operating sections of the engine and the motor, respectively (S100, S110, S120, and S130).

The maximum power distribution ratio max PSR, which is the maximum value of the power distribution ratio which means the output ratio between the engine and the motor, is the maximum torque (engine_max_torque) of the engine determined according to the engine speed XVEL. The minimum power distribution ratio (min PSR) has a minimum value of 0 when the output power of the engine is 0 (S140).

In the above, as the power distribution ratio (PSR) is calculated according to the operating section of the hybrid vehicle, the HVC 200 may determine an ordered pair of driving powers distributed to the engine and the motor in each operating section, The engine fuel consumption amount fc_e according to the output power Pe is calculated by Equation 1 below (S150 and S160).

In the above, bsfc is an abbreviation of Brake Specific Fuel Consumption and is a value representing the amount of fuel consumed by the engine per unit output power.

Subsequently, the HVC 200 receives the efficiency eta_m of the motor and the efficiency eta_b of the battery and calculates the equivalent fuel consumption fc_m consumed by the motor by Equation 2 below (S170, S180, and S190).

Ec_m is the consumed electrical energy.

Since the efficiency of the motor (eta_m), the efficiency of the battery (eta_b) and the bsfc value of the engine vary depending on the conditions under which the battery is charged, the equivalent fuel consumption (fc_m) consumed by the motor is defined as a constant value. Rather, it is expressed probabilisticly.

Therefore, the HVC 200 converts the electric energy ec_m consumed by the electric motor into the equivalent fuel consumption fc_m using the equivalent coefficient e_bsfc (S200).

That is, the equivalent coefficient e_bsfc for converting the electric motor energy into fuel may be expressed as ec_m / (eta_m × eta_b) × bsfc. Therefore, when the value is substituted into Equation 2, Equation 3 may be expressed.

In Equation 3, e_bsfc is a function determined according to the operating points of the engine and the motor. Therefore, in order to obtain the e_bsfc, the operation intervals of the engine and the motor are divided at regular intervals, and the value of e_bsfc in each operation interval should be evaluated using Equation 3 above.

Subsequently, the HVC 200 multiplies the respective values of the equivalent coefficients e_bfsc of the electric motor energy fuel converted by the probability to calculate a representative value as shown in Equation 4 below (S210).

Subsequently, the HVC 200 obtains an average value for the representative value of the e_bsfc calculated above, and then calculates a factor for converting the motor energy fuel consumption to calculate the battery energy consumption (calculated in SOC drop) in the calculated factor. Multiply the energy consumption of the electric motor by the fuel consumption (fc_m) (S220, S221, S230).

Subsequently, the HVC 200 calculates the actual fuel consumption amount fc_total of the hybrid electric vehicle by adding the energy consumption fc_m of the electric motor converted above to the fuel consumption amount fc_e of the engine (S240).

fc_total = fc_e + fc_m

In addition, the fuel consumption of the hybrid electric vehicle is calculated by dividing the fuel consumption amount fc_total of the hybrid electric vehicle calculated above by the vehicle's driving distance (S241 and S250).

Thus, in the hybrid electric vehicle, it is possible to calculate the fuel economy of the entire vehicle taking into account both the fuel consumption of the engine and the energy consumption of the electrical system, and thus it is possible to evaluate the actual fuel efficiency of the hybrid vehicle in one test.

As described above, according to the present invention, the electric energy consumed while driving in a hybrid vehicle must be replenished by using the power of the engine, and thus the electric energy consumption can be defined as the fuel consumption in the engine consumed when recharging it. Accordingly, by calculating the fuel economy of the entire vehicle taking into account both the fuel consumption of the engine and the energy consumption of the electrical system, the actual fuel economy of the hybrid vehicle can be evaluated in one test.

Claims (2)

A fuel economy calculation method for a hybrid vehicle, comprising: dividing an operation section according to a ratio of engine driving and motor driving by receiving a hybrid structure, engine efficiency, and motor efficiency; Iteratively calculating an equivalent coefficient for converting electrical energy in each operation section divided in the step into fuel; Calculating an average of the equivalent coefficients by calculating representative values of the equivalent coefficients repeatedly calculated in the above steps, and calculating fuel consumption of the vehicle using the averages of the equivalent coefficients; And calculating fuel efficiency by dividing the fuel consumption calculated in the step by a mileage. The method of claim 1, further comprising: calculating a battery energy consumption to an average value of the equivalent coefficient of the electrical energy and converting the battery energy consumption factor into an electric energy fuel consumption factor; And calculating the fuel consumption of the vehicle by adding the engine fuel consumption to the electric energy fuel consumption factor converted in the step.