Method, device and system for controlling low oil consumption of diesel engine

Abstract

The invention discloses a control method, device and system for low fuel consumption of a diesel engine. The control method comprises the following steps that the current engine rotating speed and fuel injection quantity of the diesel engine are obtained; a look-up table MAP is searched according to the engine rotating speed and the fuel injection quantity so as to determine the main injection advance angle, the EGR valve opening degree and the air demand quantity, and the main injection advance angle, the EGR valve opening degree and the air demand quantity corresponding to different engine rotating speeds and fuel injection quantities are stored in the look-up table; and a control instruction of the engine is generated according to the main injection advance angle, the EGR valve opening degree and the air demand quantity. According to the method, the current engine rotating speed and the current fuel injection quantity of the diesel engine are obtained, the pumping loss work of the engine is reduced by opening the EGR valve, the maximum main injection advance angle under the working condition point is obtained when the EGR valve is opened, and the fuel consumption level of the diesel engine under the working condition is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine control technology, and specifically relates to a control method, device and system for low fuel consumption of diesel engines. Background Technology

[0002] Diesel engines, due to their high power output and good fuel economy, remain the primary power source for commercial trucks and are widely used in various commercial vehicles. Furthermore, diesel engines excel in heavy-duty transportation, balancing power and economy, making them the preferred power source for long-distance transport and heavy-haul freight.

[0003] To meet the emission limits of the China VI emission standards, current diesel engines primarily utilize cold-end exhaust gas recirculation (EGR) to control in-engine nitrogen oxide emissions. As market competition intensifies, OEMs are continuously enhancing engine rated power through turbocharging and intercooling technologies, but to control engine costs, they still employ exhaust gas turbochargers. To increase intake air volume, the boost pressure ratio must be continuously increased, ultimately leading to high-boost or even ultra-high-pressure turbocharging technologies. However, while high or ultra-high pressure ratios increase system intake pressure and increase intake air volume, further boosting engine power, they also lead to a significant increase in pumping power losses under partial load conditions in the mid-to-high engine speed range, resulting in worsened fuel consumption. Furthermore, a reasonable main injection advance angle ensures more complete combustion and the lowest specific fuel consumption, but an excessively high boost pressure ratio causes the maximum in-cylinder pressure to exceed the engine's design limits, thus preventing optimal fuel consumption. Summary of the Invention

[0004] To address the problem of fuel consumption deterioration caused by the use of high pressure ratios or ultra-high pressure ratios in existing methods, this invention provides a method, device, and system for controlling low fuel consumption in diesel engines, effectively improving fuel consumption levels.

[0005] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a method for controlling low fuel consumption in a diesel engine, comprising the following steps: Obtain the current engine speed and fuel injection quantity of the diesel engine; The main injection advance angle, EGR valve opening, and air demand are determined by consulting the lookup table MAP based on the engine speed and fuel injection quantity. The lookup table stores the main injection advance angle, EGR valve opening, and air demand corresponding to different engine speeds and fuel injection quantities. The main injection advance angle, EGR valve opening, and air demand are determined by testing at the engine speed and fuel injection quantity, and are the main injection advance angle, EGR valve opening, and air demand corresponding to the condition where the in-cylinder explosion pressure is less than or equal to the maximum design allowable explosion pressure and the fuel consumption no longer decreases. Engine control commands are generated based on the main injection advance angle, EGR valve opening, and air demand.

[0006] A second aspect of the present invention provides a control device for low fuel consumption of a diesel engine, comprising a memory and a controller connected in sequence, wherein the memory stores a computer program, and the controller is used to read the computer program and execute a control method for low fuel consumption of a diesel engine as described in the first aspect and any of its possibilities.

[0007] The third aspect of the present invention provides a control system for low fuel consumption of a diesel engine, comprising a control device for low fuel consumption of a diesel engine as described in the second aspect, a data acquisition unit connected to the control device for low fuel consumption of the diesel engine, and an engine. The data acquisition unit includes an engine speed acquisition unit and a fuel injection quantity acquisition unit.

[0008] Compared with the prior art, the present invention has at least the following advantages and beneficial effects: This invention reduces the pumping power loss of the diesel engine by obtaining the current engine speed and fuel injection quantity and opening the EGR valve. Furthermore, by opening the EGR valve, the maximum main injection advance angle at this operating point is obtained, which effectively improves the fuel consumption level of the diesel engine under this operating condition. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0012] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0013] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0014] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0015] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0016] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0017] The first aspect of this invention discloses a method for controlling low fuel consumption in a diesel engine, such as... Figure 1As shown, the method includes steps S01 to S03. This method can be, but is not limited to, executed by a diesel engine low-fuel-consumption control device, namely the diesel engine's ECU.

[0018] Step S01: Obtain the current engine speed and fuel injection quantity of the diesel engine.

[0019] Specifically, this step first acquires the current engine speed of the diesel engine collected by the engine speed sensor and the throttle position data collected by the throttle position sensor; then, the fuel injection quantity is calculated based on the throttle position data.

[0020] Step S02: Based on the engine speed and fuel injection quantity, look up the lookup table MAP to determine the main injection advance angle, EGR valve opening, and air demand. The lookup table stores the main injection advance angle, EGR valve opening, and air demand corresponding to different engine speeds and fuel injection quantities. The main injection advance angle, EGR valve opening, and air demand are determined by testing at the engine speed and fuel injection quantity, and are the main injection advance angle, EGR valve opening, and air demand corresponding to the condition where the in-cylinder combustion pressure is less than or equal to the maximum design allowable combustion pressure and the fuel consumption no longer decreases.

[0021] EGR valve is the exhaust gas recirculation valve.

[0022] The lookup table in this step is generated based on the results of the diesel engine's universal characteristic test on a bench. During the bench test, the diesel engine is operated under different conditions within the medium-to-high speed range, i.e., tested at different engine speeds and fuel injection quantities. At a given engine speed and fuel injection quantity, the air demand is continuously adjusted, and the EGR opening is gradually increased. Opening the EGR valve reduces the engine's pumping power loss. After the EGR is open, the main injection advance angle is continuously increased, and the in-cylinder combustion pressure and specific fuel consumption are monitored. When the in-cylinder combustion pressure is less than or equal to the maximum design-allowed combustion pressure, and the specific fuel consumption no longer decreases, the optimal main injection advance angle, EGR valve opening, and air demand corresponding to that engine speed and fuel injection quantity can be obtained. This main injection advance angle, EGR valve opening, and air demand can control the diesel engine to achieve the lowest fuel consumption. Thus, the maximum main injection advance angle at that engine speed and fuel injection quantity can be obtained, effectively improving the fuel consumption level of the diesel engine under that operating condition.

[0023] By employing the aforementioned bench test procedure, the optimal main injection advance angle, EGR valve opening, and air demand corresponding to different engine speeds and injection quantities can be obtained. The obtained test data is then written into the engine control unit, allowing the optimal main injection advance angle, EGR valve opening, and air demand for different engine speeds and injection quantities to be determined by looking up a table.

[0024] Step S03: Generate engine control commands based on the main injection advance angle, EGR valve opening, and air demand.

[0025] By employing the above method, the pumping loss under partial load conditions in the medium-to-high speed range of the engine is reduced by opening the EGR valve, thereby improving the engine's thermal efficiency and achieving the goal of reducing diesel engine fuel consumption. By opening the EGR, the maximum combustion pressure in the engine cylinder can be effectively reduced, thereby adjusting the main injection angle and making the engine combustion more complete, thus achieving the optimal specific fuel consumption under this operating condition.

[0026] For example: For a certain model of diesel engine, the rated power point speed is 3000 rpm, the rated power is 125 kW, and the design maximum allowable explosion pressure is 175 MPa. Universal characteristic tests were conducted on the engine on a bench. At the mid-to-high speed operating point one: engine speed was 2600 rpm, power was 34 kW, throttle opening was 52%, current EGR opening was 0%, the cycle injection quantity was 27 mg / hub, the required intake air volume was 1485 mg / hub, the actual intake air volume was 1485.6 mg / hub, the main injection advance angle was 11.2 deg CrS, and the specific fuel consumption was 257.3 g / kW∙h. At this point, the air demand was continuously reduced, the opening was continuously increased until the specific fuel consumption no longer decreased. Then, the main injection advance angle was increased and the EGR valve opening was increased. Because the load was relatively small at this operating point, when the actual EGR opening was 55% and the main injection advance angle was 11.5 deg CrS, the maximum burst pressure in the engine cylinder was still lower than the design maximum allowable burst pressure of 175MPa, but the specific fuel consumption no longer decreased and stabilized at 237.5 g / kW∙h. The test was then ended, and the current engine cycle injection quantity was recorded as 24.8 mg / hub, and the actual intake air quantity was 842.6 mg / hub.

[0027] Mid-to-high speed operating condition 2: Engine speed is 2600 rpm, power is 68.1 kW, throttle opening is 76%, current EGR opening is 0%, cyclic fuel injection quantity is 46.5 mg / hub, required intake air volume is 1557.2 mg / hub, actual intake air volume is 1557.8 mg / hub, main injection advance angle is 13.93 degrees, and specific fuel consumption is 215.1 g / kW∙h; By continuously reducing the air demand, opening and increasing the EGR valve opening until the specific fuel consumption no longer decreased, the main injection advance angle was increased and the EGR valve opening was further increased. Because the load was high at this operating point, when the actual EGR opening was 45% and the main injection advance angle was 14.9 degCrS, the maximum in-cylinder combustion pressure stabilized at the design-allowed maximum combustion pressure of 175 MPa, but the specific fuel consumption no longer decreased, stabilizing at 210.8 g / kW∙h. The test was then concluded, and the current engine cycle injection quantity was recorded as 45.4 mg / hub, and the actual intake air quantity as 1117.9 mg / hub.

[0028] As can be seen from the above embodiments, the control method for reducing fuel consumption in the high-speed range of a turbocharged diesel engine using EGR provided in this application can effectively reduce the engine's specific fuel consumption.

[0029] A second aspect of the present invention provides a control device for low fuel consumption of a diesel engine, comprising a memory and a controller connected in sequence via communication. The memory stores a computer program, and the controller is used to read the computer program and execute a control method for low fuel consumption of a diesel engine as described in the first aspect and any possible thereof. Specifically, the memory may include, but is not limited to, random-access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or first-in-last-out (FILO) memory, etc.; the controller may not be limited to using a microcontroller of the STM32F105 series. Furthermore, the computer device may also include, but is not limited to, a power supply unit, a display screen, and other necessary components.

[0030] The third aspect of the present invention provides a control system for low fuel consumption of a diesel engine, comprising a control device for low fuel consumption of a diesel engine as described in the second aspect, a data acquisition unit connected to the control device for low fuel consumption of the diesel engine, and an engine. The data acquisition unit includes an engine speed acquisition unit and a fuel injection quantity acquisition unit.

[0031] Specifically, the fuel injection quantity acquisition unit is a throttle position sensor.

[0032] The operating principles of the apparatus and system disclosed in the second and third aspects of this invention are detailed in the first aspect and will not be repeated here.

[0033] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling low fuel consumption in a diesel engine, characterized in that, Includes the following steps: Obtain the current engine speed and fuel injection quantity of the diesel engine; The main injection advance angle, EGR valve opening, and air demand are determined by consulting the lookup table MAP based on the engine speed and fuel injection quantity. The lookup table stores the main injection advance angle, EGR valve opening, and air demand corresponding to different engine speeds and fuel injection quantities. The main injection advance angle, EGR valve opening, and air demand are determined by testing at the engine speed and fuel injection quantity, and are the main injection advance angle, EGR valve opening, and air demand corresponding to the condition where the in-cylinder explosion pressure is less than or equal to the maximum design allowable explosion pressure and the fuel consumption no longer decreases. Engine control commands are generated based on the main injection advance angle, EGR valve opening, and air demand.

2. The method for controlling low fuel consumption of a diesel engine according to claim 1, characterized in that: The process of obtaining the current engine speed and fuel injection quantity of the diesel engine includes: Acquire the current engine speed of the diesel engine from the engine speed sensor and the throttle position data from the throttle position sensor; The fuel injection quantity is calculated based on the throttle position data.

3. A control device for low fuel consumption of a diesel engine, comprising a memory and a controller connected in sequence via communication, wherein the memory stores a computer program, characterized in that: The controller is used to read the computer program and execute the control method for low fuel consumption of a diesel engine as described in any one of claims 1 to 2.

4. A control system for low fuel consumption in a diesel engine, characterized in that, Includes a diesel engine low fuel consumption control device as described in claim 3, a data acquisition unit with signals connected to the diesel engine low fuel consumption control device, and an engine; The data acquisition unit includes an engine speed acquisition unit and a fuel injection quantity acquisition unit.

5. The control system for low fuel consumption of a diesel engine according to claim 4, characterized in that: The fuel injection quantity acquisition unit is a throttle position sensor.

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