Control method for low-speed dynamic response of engine

Abstract

The invention discloses a control method for low-speed power response of an engine, which comprises the following steps of: calibrating a low-speed state of a vehicle by acquiring a vehicle speed, a gear and an engine rotating speed signal, judging that a driver has a strong power demand according to a current accelerator change rate, a current fuel quantity change rate and a current fuel injection quantity signal, and controlling the engine to respond to the strong power in a low-vehicle-speed state and a high-power-demand state. And the engine ECU controller controls the compressed air bottle to supply air to the engine combustion chamber. According to the invention, a series of problems in the prior art that changes of vehicle speed and power demand are not considered and the dynamic demand of power cannot be responded well are solved, and the low-speed dynamic property and responsiveness of the engine can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of engine control, and in particular to a method for controlling low-speed power response of an engine. Background Art

[0002] Traditional internal combustion engines are often limited by the low-speed intake volume at low speeds, resulting in limited maximum fuel injection volume, less fuel, and small torque output from combustion, which in turn leads to slow response to the driver's power. During driving, the impacts are generally stalling at start, lack of ability to climb at low speed, and slow acceleration. Even after adding a turbocharger, this problem is still not well improved, because the turbocharger intervention speed is usually above 1100r / min engine speed. Before it is lower than the supercharger intervention speed, the supercharger cannot increase the intake volume well, and the power and responsiveness problems still exist.

[0003] Patent publication number "CN106194403A" discloses a method and device for improving the low-speed power and acceleration responsiveness of a turbocharged engine, wherein the engine is supplied with air by a turbocharger; it also includes an auxiliary air supply device for supplying air to the engine when the turbocharger does not supply enough air to the engine, and the electronic controller of the engine detects the air supply condition of the turbocharger to the engine in real time and determines whether the air supply condition meets the preset air demand of the engine; if the electronic controller detects that the air supply condition of the turbocharger does not meet the preset air demand of the engine, the electronic controller sends a notification signal to the auxiliary air supply device to notify the auxiliary air supply device to work, thereby realizing auxiliary air supply to the engine. The auxiliary air supply device includes an air compressor, an air filter device, an air storage device, and an air management device.

[0004] The defects of the above prior art are:

[0005] 1. The engine's electronic controller detects the turbocharger's air supply to the engine in real time. It only detects the turbocharger's air supply value, but does not take into account a series of problems such as changes in vehicle speed and power demand, and cannot respond well to dynamic power demand;

[0006] 2. Failure to consider filtering signals leads to incorrect judgment of gas supply demand, frequent opening of the solenoid valve to supply gas and excessive consumption of gas;

[0007] 3. Since gas is easily consumed, the air supply is carried out by using an air compressor, which causes the air supply device to occupy a large space and have a complex structure.

[0008] The information disclosed in the above background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as admitting or suggesting in any form that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0009] In view of the above-mentioned existing defects, the purpose of the present invention is to provide a control method for the low-speed power response of the engine, which combines the ECU software control logic and the compressed air bottle that comes with the vehicle. When the driver has a strong power demand, the engine intake air is supplemented from the compressed air bottle, thereby improving the low-speed power and responsiveness of the engine.

[0010] The technical solution of the present invention is as follows:

[0011] A control method for low-speed power response of an engine comprises the following steps: S1: obtaining current vehicle speed, gear position, and engine speed signals; if the current vehicle speed is less than a preset vehicle speed, the current gear position is less than a preset gear position, and the current engine speed is less than a preset engine speed, when all three conditions are satisfied, it is calibrated to a low vehicle speed state; S2: obtaining current throttle change rate, fuel quantity change rate, and fuel injection quantity signals; if the current vehicle throttle change rate is greater than a calibrated change rate, the fuel injection quantity change rate is greater than a calibrated change rate, and the current fuel injection quantity plus a calibrated deviation fuel quantity is greater than the smoke limit fuel quantity under an air-fuel ratio state, when one of the three conditions is satisfied, it is calibrated to a high power demand state; S3: in the low vehicle speed state and the high power demand state, the engine ECU controller controls a compressed air bottle to replenish air to an engine combustion chamber.

[0012] Specifically, step S3 also includes: setting the activation delay time, including setting the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, and comparing with the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is longer than the longest excitation electronic valve opening time Tl, the gas is compensated according to the longest excitation electronic valve opening time Tl; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is between the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, the gas is compensated according to the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is shorter than the shortest excitation electronic valve opening time Ts, the gas is compensated according to the shortest excitation electronic valve opening time Ts.

[0013] Specifically, step S3 also includes: setting a calibration filter time T0, and comparing it with the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state. If the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is less than the calibration filter time T0, S3 is not executed.

[0014] Beneficial effects of the present invention:

[0015] (1) The present invention obtains vehicle speed, gear position, and engine speed signals to calibrate the low-speed state of the vehicle, and then determines whether the driver has a strong power demand through the current throttle change rate, oil volume change rate, and fuel injection volume signals, thereby controlling the compressed gas cylinder to supplement the engine intake air, thereby improving the low-speed power and responsiveness of the engine, solving a series of problems in the prior art that the changes in vehicle speed and power demand are not taken into account and the dynamic demand for power cannot be well responded to;

[0016] (2) Through the filtering setting and activation delay setting of this solution, the air intake of the air bottle is intelligently judged and compressed, and the air intake volume is accurately controlled. The demand is met with less air intake, thereby saving air intake and reducing the volume of the air intake device, without the need for a complex air compressor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of the steps of a method for controlling low-speed power response of an engine.

[0018] Figure 2 The figure is a schematic diagram of the structure of a method for controlling low-speed dynamic response of an engine according to the present invention.

[0019] Figure 3 The present invention is a control logic block diagram of a method for controlling low-speed power response of an engine. DETAILED DESCRIPTION

[0020] In order to explain the technical content, purpose and effect of the present invention in detail, the following is an explanation in combination with embodiments and accompanying drawings. In the description of the embodiments, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0021] like Figure 1-3 As shown, according to a specific implementation method of the present invention, a control method for low-speed power response of an engine is provided, and its framework structure basically adopts a turbocharger system of the prior art, such as Figure 2 As shown, a turbocharger is used to supply air to the engine. A compressed air bottle is also included, and the compressed air bottle is controlled to open or close ventilation through an electronic control valve to assist in supplying air to the engine combustion chamber.

[0022] In this embodiment, the control method of the engine low speed power response includes the following steps:

[0023] S1: In this embodiment, the current vehicle speed, gear position, and engine speed signals are obtained through the vehicle VCU controller, and the engine ECU controller compares the obtained signals. When the gear position is less than the set gear position, the output state is TRUE, otherwise it is FALSE; when the vehicle speed is less than the set vehicle speed, the output state is TRUE, otherwise it is FALSE; when the engine speed is less than the set engine speed value, the output state is TRUE, otherwise it is FALSE; when all three output states are TRUE, it is calibrated as a low vehicle speed state; by adding the low vehicle speed state as one of the conditions in the logic program, the solenoid valve can be activated and opened.

[0024] S2: Get the current throttle change rate, fuel quantity change rate, and fuel injection quantity signal. If the current vehicle throttle change rate is greater than the calibrated change rate, the fuel injection quantity change rate is greater than the calibrated change rate, and the current fuel injection quantity plus the calibrated deviation fuel quantity is greater than the smoke limit fuel quantity under the air-fuel ratio state, and the state outputted by one of the three is TURE, it is calibrated as a high power demand state;

[0025] Throttle change rate: The rate of change of the accelerator pedal opening. The faster you step on the accelerator, the greater the throttle change rate, which represents the driver's urgent need for power. For example, within 100ms, the throttle opening increases from 0% to 30%, and the throttle change rate is 300% / s.

[0026] Oil volume change rate: the growth rate of the injection volume. When strong power is needed, the growth rate of the oil volume will be large. For example, when the injection volume is 100ms, the injection volume increases from 20mg per stroke to 40mg per stroke, and the oil volume change rate is 200mg / hub / s.

[0027] Smoke limit fuel quantity: It is calculated to get the maximum fuel quantity that can be injected under the current intake volume. The actual injection quantity is always less than or equal to the smoke limit fuel quantity. The three judgments are used to determine whether the driver currently has a strong demand for power.

[0028] S3: Under low vehicle speed and high power demand conditions, the engine ECU controller controls the solenoid valve to open, and the compressed air bottle replenishes air to the engine combustion chamber to increase the intake boost pressure and improve the problem of insufficient low-speed intake.

[0029] When the engine is at low speed, the supercharger cannot intervene, the boost pressure is low, the intake volume is small, the air is small, the maximum fuel injection volume that can support combustion will be limited, and the torque generated by combustion will also be small, which in turn affects the engine's power and responsiveness at low speed. Through this embodiment, combined with the ECU software control logic and the vehicle's own compressed air bottle that can be appropriately expanded, the calibrated vehicle speed state is directly judged. When the driver has a strong demand for power, the engine intake is supplemented from the compressed air bottle, thereby improving the engine's low-speed power and responsiveness. The above procedures are implemented through the software and logic chip control in the engine ECU controller. For example, the current National VI engine uses a Bosch electronic control system or a Delphi electronic control system.

[0030] like Figure 3 As shown, as the preferred technical solution of this embodiment, step S3 also includes: setting the activation delay time through the engine ECU controller, including setting the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, and comparing with the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state. If the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is longer than the longest excitation electronic valve opening time Tl, the gas is compensated according to the longest excitation electronic valve opening time Tl; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is between the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, the gas is compensated according to the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is shorter than the shortest excitation electronic valve opening time Ts, the gas is compensated according to the shortest excitation electronic valve opening time Ts.

[0031] Taking into account the time efficiency of acceleration responsiveness or the smoke limit time of the engine during acceleration, which is usually 3 to 4 seconds, it is recommended to set the maximum effective opening time of the electronic valve to 3 seconds and the minimum effective opening time to 2 seconds.

[0032] As the preferred technical solution of this embodiment, step S3 also includes: setting a calibration filter time T0, and comparing it with the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state; if the duration signal T that simultaneously satisfies the low vehicle speed state and the high power demand state is less than the calibration filter time T0, S3 is not executed.

[0033] The filter setting is to remove signals where all conditions are met but the time to meet the conditions is extremely short, so as to prevent the program from misjudging the driver's power demand. For example, if the time to meet the conditions is only 0.1s, if such signals are not filtered out, the solenoid valve will be opened to supplement compressed air, which will misjudge the driver's power demand. Frequent opening of the solenoid valve to supply air will also consume the compressed air in the cylinder too quickly.

[0034] In summary, the present invention improves the low-speed power and responsiveness of the engine by coordinating the ECU software control logic and adding some devices to the whole vehicle. Through the filtering setting and activation delay setting of this scheme, the air intake of the air bottle is intelligently judged and compressed, and the intake volume is accurately controlled. The demand is met with less air intake, thereby saving the intake volume, reducing the volume of the intake device, and eliminating the need for a complex air compressor device, thereby achieving the purpose of this embodiment.

[0035] Although the present invention has been described in detail above with specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A method for controlling low-speed dynamic response of an engine, characterized in that: The steps include: S1: Obtain the current vehicle speed, gear position, and engine speed signal. If the current vehicle speed is less than the preset vehicle speed, the current gear position is less than the preset gear position, and the current engine speed is less than the preset engine speed, when all three conditions are met, it is marked as a low speed state; S2: Get the current throttle change rate, fuel quantity change rate, and fuel injection quantity signal. If the current vehicle throttle change rate is greater than the calibrated change rate, the fuel injection quantity change rate is greater than the calibrated change rate, and the current fuel injection quantity plus the calibrated deviation fuel quantity is greater than the smoke limit fuel quantity under the air-fuel ratio state, when one of the three states is met, it is calibrated as a high power demand state; S3: Under low vehicle speed and high power demand conditions, the engine ECU controller controls the compressed air bottle to replenish air to the engine combustion chamber.

2. The method for controlling the low-speed dynamic response of an engine according to claim 1, characterized in that: Step S3 also includes: The activation delay time is set, including setting the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, and compared with the duration signal T that satisfies both the low vehicle speed state and the high power demand state. If the duration signal T that satisfies both the low vehicle speed state and the high power demand state is longer than the longest excitation electronic valve opening time Tl, the gas is compensated according to the longest excitation electronic valve opening time Tl; if the duration signal T that satisfies both the low vehicle speed state and the high power demand state is between the shortest excitation electronic valve opening time Ts and the longest excitation electronic valve opening time Tl, the gas is compensated according to the duration signal T that satisfies both the low vehicle speed state and the high power demand state; if the duration signal T that satisfies both the low vehicle speed state and the high power demand state is shorter than the shortest excitation electronic valve opening time Ts, the gas is compensated according to the shortest excitation electronic valve opening time Ts.

3. The method for controlling the low-speed dynamic response of an engine according to claim 1, characterized in that: Step S3 also includes: A calibration filter time T0 is set and compared with the duration signal T that satisfies both the low vehicle speed state and the high power demand state. If the duration signal T that satisfies both the low vehicle speed state and the high power demand state is less than the calibration filter time T0, S3 is not executed.

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