KR101405745B1 - Engine Torque Control Method in Vehicle - Google Patents

Abstract

The engine torque control method for a vehicle of the present invention uses the generator power calculated from the load change of the generator 1 to calculate the DELTA engine torque which is changed in the engine 5, and the DELTA engine torque is added to the engine torque, And the ECU 3 controls the engine 5 with the target engine torque to utilize the detected power load accurately as feedback duty of the generator at a point of time when the power generation amount change (load change) And the engine control is performed by the ECU under the condition that the target torque required for the engine control is calculated by the precisely sensed power generation load, so that the safety of the engine control can be greatly improved and the NVH (Noise, Vibration, Harshness) .

Description

TECHNICAL FIELD [0001] The present invention relates to an engine torque control method,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to engine control of a vehicle, and more particularly, to a method of controlling an engine torque of a vehicle that can significantly contribute to stabilization of engine control by utilizing a change in power generation load of a generator in engine torque control.

In general, batteries, which are the most important components in electric vehicles and hybrid vehicles, store and discharge energy while charging and discharging.

Generally, the amount of charge of the battery is performed in a power generation controllable range. To this end, the generator charges the battery by a generator voltage variation control method by an engine control unit (ECU).

As an example of a generator voltage fluctuation control method of an ECU (Engine Control Unit), there is a method in which a battery is charged while controlling a generator to a fixed voltage at the beginning of running of the vehicle, or the generator is mainly controlled to discharge- Is controlled by acceleration, constant speed, idle or deceleration of the vehicle while maintaining the charged state of the battery at a constant level.

Particularly, when the load of the generator is controlled during the running of the vehicle, it can greatly contribute to the improvement of the fuel efficiency, and such a control method is inevitably required in accordance with the high oil price era.

As an example of load control of a generator, an engine control unit (ECU) increases the load of a generator during a decelerating operation in which fuel is consumed less, thereby increasing the production of electric energy charged in the battery, There is a way to significantly reduce the production of electric energy by using the stored energy of the battery.

As described above, the degree of power generation of the generator is controlled according to the traveling pattern of the vehicle, so that the fuel consumption of the engine can be reduced and the fuel consumption can be further improved.

Feedback duty control is generally applied to the feedback control system of the vehicle by controlling the duty value of the feedback solenoid valve.

Therefore, when the ECU performs the generator control with the feedback duty of the generator, the load of the generator can be detected according to the level of the duty, so that the ECU can utilize the feedback duty of the generator for engine control.

Domestic patent registration 10-0792892 (January 02, 2008)

The patent document shows an example of a technique capable of satisfying the optimum required torque of the engine required by the vehicle by allowing the hybrid vehicle to recognize and enter the full load state of the engine.

However, the above-mentioned patent document requires a control method that utilizes the feedback duty of the generator in an engine control unit (ECU) at the time of engine control by requiring a main controller (HCU) and an engine controller (EMS) And there is no difference in the difficulty of ensuring the safety of the engine control when utilizing the feedback duty of the generator.

This is a fundamental limitation in using a simple feedback duty at the point of time when the change in generator power generation increases when the ECU controls the engine, and this tendency is inevitably exacerbated in a vehicle with improved performance.

For example, a change in power generation leads to a torque change in which the torque of the engine is increased on the engine side, but inaccurate recognition of the point of time when the change in the power generation amount of the generator increases in such a state has an adverse effect on the relief of the engine.

Therefore, there is a fundamental limitation in ensuring the safety of the engine control in a system in which the ECU simply uses the feedback duty of the generator in engine control.

In view of the above, it is an object of the present invention to provide a power generation apparatus and a power generation method that utilize a power generation load precisely sensed at a point of time when a change in a power generation amount of the power generator (load change) increases as a feedback duty of the power generator, The safety of the engine control can be greatly enhanced by the ECU performing the engine control under the condition that the target torque necessary for the engine control with the load is calculated. In particular, since the sensor is not used for detecting the generation load of the generator, And to provide a method of controlling an engine torque of a vehicle that can greatly increase the engine torque.

To achieve the above object, there is provided a method for controlling engine torque of a vehicle, comprising the steps of: when there is a checked generator load change in a vehicle under running, the engine torque is changed by the engine using the generator power calculated from the generator load change The DELTA engine torque is added to the engine torque to be converted into the target engine torque, and the engine is controlled to the target engine torque;

Is included.

The generator rotational speed RPM is determined by the generator rotational speed RPM, the specific rotational speed a, the generator rotational speed RPM, the generator rotational speed RPM, RPM), and the generator duty is a condition of the generator duty> specific duty (b,%).

The generator power is calculated from the final current and voltage of the generator.

The final current of the generator is obtained by correcting the current of the generator calculated at the time when the generator load is changed to the temperature of the generator.

Wherein an application factor for calculating the generator current is an engine speed (RPM) of the engine and a duty value (%) of the generator, and an application condition for temperature correction of the generator is an engine speed Cooling water temperature, intake air temperature supplied to the engine, and outdoor temperature supplied from the atmosphere to the engine.

The generator voltage is a battery voltage.

The application factor for calculating the DELTA engine torque is the generator power and efficiency (?) And the engine speed (RPM).

If there is no change in the generator load, the target engine torque is the engine torque.

The target engine torque control is continued according to the generator load change if the engine is not turned off.

According to another aspect of the present invention, there is provided a method for controlling engine torque of a vehicle, the method comprising the steps of: determining a generator load change through a generator rotation speed (RPM) or a generator duty ;

The generator current is calculated using the engine speed (RPM) and the generator duty at a time point when the generator load is changed, and the generator current is calculated using the engine coolant temperature and the intake air supplied to the engine Calculating a generator final current by correcting the generator current to a temperature of the generator calculated using an outside temperature supplied from the atmospheric air to the engine, calculating a generator power from the voltage of the generator together with the generator final current, An engine torque calculating step of calculating a DELTA engine torque to be varied in the engine using the efficiency (?) And the engine speed (RPM);

The engine torque is calculated as the target engine torque of the engine in addition to the engine torque, or the engine torque is calculated as the target engine torque of the engine in the absence of the generator load change, A generator-linked engine control step of controlling the generator-connected engine;

Is further included.

In the present invention, the power generation load is precisely sensed at the point of time when the change in the power generation amount of the generator increases, and is utilized as the feedback duty of the generator. Thus, the target torque necessary for the engine control is controlled, The safety of the control is greatly increased.

In addition, the present invention greatly improves the NVH (Noise, Vibration, Harshness) of the engine by accurately detecting the power generation load of the generator and greatly improving the safety of the engine control with the target torque of the engine calculated therefrom.

Further, according to the present invention, the power generation load of the generator is precisely detected without using a separate sensor, and the safety of the engine control can be greatly improved together with the generator load control without increasing the cost.

2 is a configuration diagram of a vehicle to which a generator control method according to the present invention is applied. FIG. 3 is a flowchart illustrating a method of controlling an engine torque of a vehicle according to the present invention. It is a characteristic diagram of applied generators and engines.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which illustrate exemplary embodiments of the present invention. The present invention is not limited to these embodiments.

1 shows a flow of a method for controlling engine torque of a vehicle according to the present embodiment.

As shown, the control logic for the engine torque control starts with the engine ON of S10 and ends with the engine OFF of S100, and the control process of S20 to S90 is performed at this stage, The safety of the engine control can be greatly improved by the power generation load accurately detected at the time when the change of the power generation amount of the engine is increased.

Fig. 2 shows an example of the configuration of a vehicle in which the above-described control logic is implemented.

As shown in the figure, the vehicle includes a generator 1, a battery 2 in which the SOC is charged by the generator 1, and a battery 2 through the sensor 7, together with vehicle information via the engine 5. [ And an ECU 3 (Engine Control Unit) for controlling the generator 1 as status information.

Usually, the vehicle is also provided with a cooling fan 20 controlled by the ECU 3 together with the electrical equipment 10 consuming the current of the battery 2.

Therefore, when the engine ON is checked in S10, the ECU 3 controls the power generation method of the generator 1 through S20 to S90 in the engine ON state, To be repeated.

Referring to FIG. 1, in step S20, in which the ECU 3 checks engine-on, the generator state is first checked first, which means a generator load.

Generally, the amount of current of the generator increases with the engine speed (RPM) and the feedback duty, which is a signal transmitted from the generator to the ECU, while the amount of current of the generator decreases with the temperature of the generator, And the efficiency varies depending on the power generation area.

Here, the feedback duty expressed in% is different from that of the generator in accordance with the engine speed (RPM) even with the same duty, and the temperature of the generator is estimated by using a separately installed sensor or by cooling water on the engine side and intake air temperature, The power generation efficiency is also increased, so that the power generation efficiency is used to convert the load of the generator to the engine load.

Therefore, the load of the generator can be detected from the above-described principle.

In this embodiment, the check factor for determining the generator load is the generator rotation speed (RPM) or the generator duty (Duty), the generator rotation speed (RPM) is based on the specific rotation speed (a) The duty is based on a specific duty (b). The specific speed (a) is RPM, and the specific duty (b) is%.

For example, generator rotation speed (RPM)> specific rotation (a, RPM) or generator duty (Duty)> specific duty (b,%) can be applied. As can be seen in the example of the feedback duty diagram (A) of the generator current-engine RPM of FIG. 3, the generator current is increased with increasing engine RPM, and the performance of the generator, % (20% or 40% or 60%). Therefore, when the generator is driven, the power generation opportunity number (RPM) can calculate the specific generator duty percentage, and the generator duty percentage can calculate the specific power generation opportunity number (RPM). For example, taking a generator duty of 20% as an example, the number of revolutions at which the generator speed is increased to 20% after the generator is driven by the engine is defined as a specific number of revolutions (a, RPM) , And the point of time when the specific rotation number (a, RPM) of the generator is reached can be defined as a specific duty (b,%). From this, it can be seen that the generator load variation is a specific duty (a, RPM) defined as "generator speed (RPM)> generator duty 20% or less", and "generator duty (Duty)> generator duty 20% (b,%) ", so that a change amount for a condition for determining the change in the generator load can be set.

Accordingly, if the result of the check in S20 is that the generator rotation speed RPM> the specific rotation speed a or RPM or the generator duty Duty> the specific duty b,% is not established, the operation is shifted to S30.

S30 indicates a state in which DELTA engine torque = 0 in which an increase in engine torque is not required, from which there is no change in the load on the generator, and the target engine torque is not changed, so that normal generator control is performed.

On the other hand, if it is determined in step S20 that the generator rotation speed RPM, the specific rotation speed a or RPM or the generator duty Duty> the specific duty b,% is established, the control flow goes to step S40 to calculate the change in engine torque Is performed.

S40 is a process in which the generator current is primarily calculated, and the engine speed (RPM) and the generator duty (%, duty) are used as an application factor for this.

In the present embodiment, the generator current is calculated by setting a specific generator load calculation area. For example, the specific generator load calculation area may include a relatively low engine speed (RPM) or a feedback duty Duty).

Typically, the specific duty (b) of the generator is obtained from the test results for the individual parts of the generator itself. The feedback duty line (A) in FIG. 3 is a relation between the generator current and the engine speed (RPM), from which the duty value (%) of the generator current according to the engine speed (RPM) is judged.

Therefore, in S40, the primarily calculated generator current value can be obtained.

S50 is a process of correcting the temperature of the generator. By doing so, the final current value of the generator, which corrects the current value of the generator to the temperature of the generator as in S50, can be calculated. This relationship can be seen from the temperature diagram (B) of FIG. 3, where the generator duty value (%) is the correlation between the generator temperature and the generator current.

To this end, the correction factor applied to the temperature correction of the generator is applied to the outside temperature together with the cooling water temperature and the intake temperature which are closely related to the engine temperature, and the generator temperature value for the specific values of the cooling water temperature, Can be obtained from the test results for them, such as in-system.

S70 is a process of calculating the power of the generator, in which the final current and voltage of the generator calculated in S60 are used, and the voltage of the generator is usually replaceable by the battery voltage.

S80 is a process of calculating DELTA engine torque, which is an increase in the engine torque required according to a change in the load of the generator. To this end, the generator power value, efficiency (eta) and engine speed (RPM) of S70 are applied, The engine torque is converted into the DELTA engine torque.

3 shows the relationship between the generator current and the engine speed RPM. From this, it can be seen that the efficiency value (%) of the generator according to the engine speed RPM can be determined.

Meanwhile, S90 is a process in which the target engine torque is calculated, whereby the target engine torque can be accurately given as the target engine torque = engine torque + DELTA engine torque by adding engine torque and DELTA engine torque (increment).

In this case, the DELTA engine torque is equal to the target engine torque = the engine torque since the engine torque is not required to increase when DELTA engine torque = 0 as in S30.

Therefore, the ECU can accurately reflect the change in the power generation amount of the generator, which causes the torque change of the engine, by controlling the generator with the feedback duty while using the target engine torque calculated from the feedback duty.

In step S100, the engine is turned off. When the engine is turned off, all the control is terminated. On the other hand, if the engine is turned on, the system returns to step S20. The load change is checked and the above-described control logic is repeated again.

As described above, in the engine torque control method of the vehicle according to the present embodiment, the DELTA engine torque that is changed in the engine 5 is calculated using the generator power calculated from the load change of the generator 1, The engine 3 is controlled by the target engine torque to increase the power generation amount change (load change) of the generator to increase the power generation load accurately detected at the time of the feedback of the generator The feedback control is performed by the ECU under the condition that the target torque required for the engine control is calculated with the power generation load accurately detected and the safety of the engine control can be greatly increased. ) Can be greatly improved.

1: Generator 2: Battery
3: ECU (Engine Control Unit)
5: Engine 7: Sensor
10: electric device 20: cooling fan

Claims (11)

If there is a checked generator load change in the running vehicle,
The DELTA engine torque that is changed in the engine is calculated using the generator power calculated from the generator load change,
The DELTA engine torque is added to the engine torque to be converted into the target engine torque,
And the engine is controlled by the target engine torque,
Wherein the generator power is calculated from the final current and voltage of the generator and the final current of the generator is corrected to the temperature of the generator and the application factor for temperature correction of the generator is determined by the cooling water temperature of the engine, And an outside air temperature supplied from the atmosphere to the engine.
The method according to claim 1, wherein the check factor for determining the generator load change is a change in generator speed (RPM) or a change in generator duty, and the generator speed (RPM) (A, RPM) defined as duty less than or equal to 20%, and the generator duty is a condition of a specific duty (b,%) defined as a generator duty> 20% Wherein the engine torque control method comprises the steps of:
delete The method according to claim 1, wherein the temperature is obtained by correcting the temperature of the generator, which is calculated at the time when the generator load is changed, to a temperature.
The engine torque control system according to claim 1, wherein the application factor for calculating the generator current is an engine speed (RPM) of the engine and a duty value (%) of the generator, Way.
The method of controlling an engine torque of a vehicle according to claim 1, wherein the cooling water temperature, the intake air temperature, and the outside air temperature are in an end condition.
The method according to claim 1, wherein the generator voltage is a battery voltage.
2. The method according to claim 1, wherein the application factor for calculating the DELTA engine torque is the generator power, the efficiency (?) And the engine speed (RPM).
The method according to claim 1, wherein, when there is no change in the generator load, the target engine torque is the engine torque.
2. The method according to claim 1, wherein the target engine torque control is continued according to the generator load change if the engine is not turned off.
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