Engine control method and related device

Abstract

The invention discloses an engine control method and a related device, and relates to the field of engines, an engine is provided with two EGR branches which are respectively connected with a large turbine runner and a small turbine runner, an engine controller determines a corresponding target EGR rate based on target performance parameters of the engine, a small runner EGR valve is controlled to be opened, and the small runner EGR valve is controlled to be closed. If the target EGR rate can be reached by only opening the small-flow-channel EGR valve, outputting a corresponding first target small-flow-channel EGR valve opening degree, and if the opening degree of the small-flow-channel EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, controlling the large-flow-channel EGR valve to be opened to reach the target EGR rate, and outputting a corresponding second target small-flow-channel EGR valve opening degree and a target large-flow-channel EGR valve opening degree. Two-way EGR gas taking is achieved by controlling the opening degree of the two-way EGR valve, the EGR rate is improved, meanwhile, the pumping loss and the rotating speed of the supercharger are reduced, and therefore oil consumption and NOx emission are reduced.

Description

Technical Field

[0001] The present invention relates to the field of engine technology, and more particularly to an engine control method and related devices. Background Art

[0002] When the engine needs to balance performance and fuel consumption, increase output power, and adapt to specific operating conditions (such as medium and high speed operation and high altitude areas), an asymmetric turbocharger is usually used. An asymmetric turbocharger is a turbine flow channel designed as a large flow channel and a small flow channel. The two flow channels are set with appropriate asymmetry according to the engine requirements. The large flow channel has a large flow capacity and low pre-turbine pressure, which can reduce high-speed pumping losses; the small flow channel has a small flow capacity and a high pre-turbine pressure, which can achieve the introduction of sufficient EGR (Exhaust Gas Recycling) flow into the engine intake manifold at low speeds.

[0003] The selection of asymmetry of an asymmetric turbocharger has a great impact on the EGR rate, turbocharger speed, NOx emissions and fuel consumption of the entire engine operating condition. If the asymmetry increases, the corresponding EGR rate decreases, which is contrary to the original purpose of selecting an asymmetric turbocharger; if the asymmetry is too small, the flow capacity of the small flow channel will be too small, which will lead to a decrease in the operating efficiency of the asymmetric turbocharger, increase pumping loss and turbocharger speed, seriously worsen fuel consumption, and increase NOx (nitrogen oxide) emissions.

[0004] Therefore, how to provide an engine control method that cooperates with an asymmetric turbocharger to achieve increasing the EGR rate while reducing pumping losses and turbocharger speed, thereby reducing fuel consumption and NOx emissions. Summary of the invention

[0005] In view of this, the present invention discloses an engine control method and related devices, so as to achieve the goal of reducing pumping loss and supercharger speed while increasing EGR rate, thereby reducing fuel consumption and NOx emissions.

[0006] An engine control method is applied to an engine controller. The engine has two exhaust gas recirculation (EGR) branches. The first EGR branch is connected to a large flow passage of a turbine and is provided with a large flow passage EGR valve. The second EGR branch is connected to a small flow passage of a turbine and is provided with a small flow passage EGR valve. The first EGR branch and the second EGR branch are connected to the same EGR flow collection device. The engine control method includes: Determining a corresponding target EGR rate based on a target performance parameter of the engine; Controlling the small flow channel EGR valve to open; If the target EGR rate can be achieved by opening only the small-channel EGR valve, outputting a corresponding first target small-channel EGR valve opening; If the opening of the small-channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-channel EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-channel EGR valve opening and target large-channel EGR valve opening.

[0007] Optionally, if the target EGR rate can be achieved by opening only the small-channel EGR valve, outputting a corresponding first target small-channel EGR valve opening includes: Controlling the small-channel EGR valve to gradually increase the opening degree from an initial opening degree according to a first preset amplitude, and obtaining a first EGR rate corresponding to each increase in the opening degree; When the first EGR rate reaches the target EGR rate and the opening of the small-channel EGR valve is less than the first set maximum opening, the corresponding first target small-channel EGR valve opening is output.

[0008] Optionally, if the opening of the small-channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-channel EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-channel EGR valve opening and target large-channel EGR valve opening, including: If the opening of the small-channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, controlling the opening of the small-channel EGR valve to maintain the first set maximum opening; Controlling the large-flow-channel EGR valve to open; Controlling the large-flow EGR valve to gradually increase the opening degree from an initial opening degree according to a second preset amplitude, and obtaining a second EGR rate corresponding to each increase in the opening degree, wherein the second EGR rate is determined based on a total EGR flow rate output by the first EGR branch and the second EGR branch; When the second EGR rate reaches the target EGR rate and the opening of the large-flow-channel EGR valve is less than the second set maximum opening, the corresponding second target small-flow-channel EGR valve opening and the target large-flow-channel EGR valve opening are output.

[0009] Optionally, it also includes: If the opening of the small-channel EGR valve reaches a first set maximum opening, the opening of the large-channel EGR valve reaches a second set maximum opening, and the corresponding EGR rate does not reach the target EGR rate, the engine is controlled to limit torque to meet the gas emission requirements of the engine.

[0010] Optionally, it also includes: determining a corresponding target intake pressure based on the target performance parameter of the engine; The opening of the purge valve is adjusted until the intake pressure of the engine reaches the target intake pressure.

[0011] Optionally, determining a corresponding target EGR rate based on a target performance parameter of the engine includes: acquiring the target performance parameter of the engine; The target EGR rate corresponding to the target performance parameter is determined from the corresponding relationship between the preset engine performance parameter and the EGR rate.

[0012] An engine control device is applied to an engine controller. The engine has two exhaust gas recirculation (EGR) branches. The first EGR branch is connected to a large flow passage of a turbine and is provided with a large flow passage EGR valve. The second EGR branch is connected to a small flow passage of a turbine and is provided with a small flow passage EGR valve. The first EGR branch and the second EGR branch are connected to the same EGR flow collection device. The engine control device includes: a target EGR rate determination unit, configured to determine a corresponding target EGR rate based on a target performance parameter of the engine; An opening control unit, used for controlling the opening of the small flow channel EGR valve; a first output unit, configured to output a corresponding first target small-channel EGR valve opening if the target EGR rate can be achieved by opening only the small-channel EGR valve; The second output unit is used to continue controlling the large channel EGR valve to open if the opening of the small channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, until the target EGR rate is reached, and output the corresponding second target small channel EGR valve opening and target large channel EGR valve opening.

[0013] An engine controller, the engine controller comprising: a memory and a processor; The memory is used to store at least one instruction; The processor is used to execute the at least one instruction to implement the engine control method described above.

[0014] A computer storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, the engine control method described above is implemented.

[0015] An engine, comprising: a first engine cylinder set, a second engine cylinder set, a first exhaust pipe, a second exhaust pipe, an intake pipe, a first EGR branch, a second EGR branch, an EGR flow collection device, an asymmetric turbocharger, a purge valve, an intercooler, and the engine controller described above; The input end of the first engine cylinder set is connected to the intake pipe, and the output end is connected to the first exhaust pipe. A large flow channel of the turbine is between the first exhaust pipe and the turbine of the asymmetric turbocharger. The large flow channel of the turbine is connected to the EGR flow collection device through the first EGR branch. The first EGR branch is provided with a large flow channel EGR valve. The input end of the second engine cylinder set is connected to the intake pipe, and the output end is connected to the second exhaust pipe. A small turbine flow passage is formed between the second exhaust pipe and the compressor of the asymmetric turbocharger. The small turbine flow passage is connected to the EGR flow collection device through the second EGR branch. The second EGR branch is provided with a small flow passage EGR valve. The EGR flow collection device is connected to the intake pipe; The intercooler is arranged between the compressor and the intake pipe; The air release valve is arranged at the exhaust end of the turbine small flow passage and the asymmetric turbocharger; The engine controller is respectively connected to the EGR flow collection device, the large-channel EGR valve, the small-channel EGR valve and the air release valve, and is used to control the opening of the large-channel EGR valve, the opening of the small-channel EGR valve and the air release valve.

[0016] It can be seen from the above technical scheme that the present invention discloses an engine control method and related devices, wherein the engine has two EGR branches, the first EGR branch is connected to the large flow channel of the turbine and is provided with a large flow channel EGR valve, the second EGR branch is connected to the small flow channel of the turbine and is provided with a small flow channel EGR valve, the first EGR branch and the second EGR branch are connected to the same EGR flow acquisition device, the engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine, first controls the small flow channel EGR valve to open, if only opening the small flow channel EGR valve can achieve the target EGR rate, outputs the corresponding first target small flow channel EGR valve opening, if the opening of the small flow channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continues to control the large flow channel EGR valve to open until the target EGR rate is reached, and outputs the corresponding second target small flow channel EGR valve opening and the target large flow channel EGR valve opening. In the present application, the small-flow EGR valve and the large-flow EGR valve are independently controlled by the engine controller, and dual-path EGR air intake is achieved by controlling the opening of the dual-path EGR valve to fully utilize the pressure difference between the pre-turbines pressure and the intake pressure, drive the EGR to obtain a higher EGR rate, achieve the target EGR rate, and avoid selecting too small asymmetry, which causes low operating efficiency of the small flow path. At the same time, dual-path EGR air intake can also reduce pumping loss and supercharger speed, so as to reduce the supercharger bleed area, thereby reducing fuel consumption and NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a dual-path EGR air intake structure in an engine with an asymmetric turbocharger disclosed in an embodiment of the present invention; Figure 2 A flow chart of an engine control method disclosed in an embodiment of the present invention; Figure 3 A schematic diagram of the structure of an engine control device disclosed in an embodiment of the present invention; Figure 4 The present invention is a schematic diagram of the structure of an engine controller disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The relevant terms are explained as follows: EGR (Exhaust Gas Recirculation) refers to the technology of introducing a part of the exhaust gas into the intake air for re-burning after combustion in the internal combustion engine of an automobile. It can reduce nitrogen oxides (NOx) in the exhaust gas and improve fuel economy.

[0020] Asymmetry refers to the ratio of the flow area of ​​the small turbine flow channel to the flow area of ​​the large turbine flow channel. This parameter directly affects the flow distribution of the turbine flow channel and has a significant impact on parameters such as EGR rate, pumping loss and fuel consumption.

[0021] In order to meet the requirements of the ever-increasing engine emission regulations, the NOx emissions of the internal combustion engine in the engine are required to be low. To achieve this requirement, EGR technology is often used. EGR technology requires a sufficient pressure difference between the turbine inlet and the intake pipe, especially under low engine speed conditions, to ensure sufficient EGR flow, which requires the use of a smaller turbine, but it will lead to excessive pre-turbine pressure at medium and high speeds, increased pumping losses, and worse fuel consumption. The use of an asymmetric supercharger can effectively solve the problems of high-speed pumping losses and supercharger overspeed, but if the asymmetry is too small, it will lead to too small flow capacity of the small flow channel, resulting in a decrease in the operating efficiency of the asymmetric turbocharger, increased pumping losses and supercharger speed, serious deterioration of fuel consumption, and increased NOx emissions.

[0022] To solve this problem, the present application provides an engine control method, which uses a dual-path EGR air intake method for an engine with an asymmetric turbocharger, and cooperates with the engine with an asymmetric turbocharger to achieve the goal of increasing the EGR rate while reducing pumping losses and turbocharger speed, thereby reducing fuel consumption and NOx emissions.

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1 , a schematic diagram of a dual-path EGR air intake structure in an engine with an asymmetric turbocharger disclosed in an embodiment of the present application, the engine comprises: a first engine cylinder set, a second engine cylinder set, a first exhaust pipe 11, a second exhaust pipe 12, an intake pipe 13, a first EGR branch 14, a second EGR branch 15, an EGR flow collection device 16, an asymmetric turbocharger 17, a purge valve 18, an intercooler 19 and an engine controller ( Figure 1 not shown).

[0025] In practical applications, the first engine cylinder set and the second engine cylinder set both include multiple engine cylinders, for example, Figure 1 In the embodiment, the first engine cylinder set includes: engine cylinder 1, engine cylinder 2 and engine cylinder 3. The second engine cylinder set includes: engine cylinder 4, engine cylinder 5 and engine cylinder 6.

[0026] Specifically, the input end of the first engine cylinder set is connected to the intake pipe 13, and the output end is connected to the first exhaust pipe 11. A large flow channel of the turbine is between the first exhaust pipe 11 and the turbine of the asymmetric turbocharger 17. The large flow channel of the turbine is connected to the EGR flow collection device 16 through the first EGR branch 14, wherein the first EGR branch 14 is provided with a large flow channel EGR valve 141.

[0027] In the present application, a first EGR cooler is also provided on the first EGR branch 14 .

[0028] Preferably, the EGR flow collection device 16 can be an EGR flow meter.

[0029] The input end of the second engine cylinder set is connected to the intake pipe 13, and the output end is connected to the second exhaust pipe 12. A small turbine flow channel is between the second exhaust pipe 12 and the compressor of the asymmetric turbocharger 17. The small turbine flow channel is connected to the EGR flow collection device 16 through the second EGR branch 15. The second EGR branch 15 is provided with a small flow channel EGR valve 151.

[0030] In the present application, a second EGR cooler is also provided on the second EGR branch 15 .

[0031] It should be particularly noted that, when only the large-channel EGR valve 141 provided on the first EGR branch 14 is opened and the small-channel EGR valve 151 provided on the second EGR branch 15 is not opened, the EGR flow value collected by the EGR flow collection device 16 is the EGR flow value on the first EGR branch 14 .

[0032] When the large-channel EGR valve 141 provided on the first EGR branch 14 and the small-channel EGR valve 151 provided on the second EGR branch 15 are both opened, the EGR flow value collected by the EGR flow collection device 16 is the sum of the EGR flow value on the first EGR branch 14 and the EGR flow value on the second EGR branch 15 .

[0033] In the present application, the input end of the EGR flow collection device 16 is connected to the first EGR branch 14 and the second EGR branch 15 respectively, and the output end of the EGR flow collection device 16 is connected to the intake pipe 13 .

[0034] The intercooler 19 is disposed between the compressor of the asymmetric turbocharger 17 and the intake pipe 13 .

[0035] The purge valve 18 is disposed at the exhaust end of the turbine small flow passage and the asymmetric turbocharger 17 .

[0036] The engine controller is respectively connected to the EGR flow collection device 16, the large-channel EGR valve, the small-channel EGR valve and the air release valve, and is used to control the opening of the large-channel EGR valve, the opening of the small-channel EGR valve and the air release valve.

[0037] In the present application, the small flow channel of the turbine and the large flow channel of the turbine are each connected to an EGR branch, that is, the large flow channel of the turbine is connected to the first EGR branch 14, and the small flow channel of the turbine is connected to the second EGR branch 15. The small flow channel establishes a high expansion ratio and has a strong EGR driving ability. The EGR rate driving ability of the large flow channel of the turbine is relatively weak, and is mainly used to provide sufficient air flow. The large flow channel EGR valve 141 on the first EGR branch 14 and the small flow channel EGR valve 151 on the second EGR branch 15 are controlled separately by the engine controller. The two-way EGR can make full use of the difference between the pre-vortex pressure of the large and small flow channels and the intake pressure to drive EGR, meet higher NOx emission requirements, and reduce the speed of the supercharger at the same time.

[0038] Among them, high expansion ratio means that the ratio of the pressure before the turbine to the pressure after the turbine in the small flow passage of the turbine is large.

[0039] The bleed valve 18 is on the small flow channel of the turbine. When the bleed valve 18 is opened, the exhaust gas in the small flow channel of the turbine can be directly discharged to the rear of the turbine, thereby reducing the speed of the supercharger. The bleed valve is an electronically controlled actuator, and the opening degree is controlled by the engine controller.

[0040] In order to achieve better performance of engines with asymmetric turbochargers, Figure 1 The dual-path EGR air intake structure in the engine with an asymmetric turbocharger is shown in the figure. The present application provides an engine control method for realizing the dual-path EGR air intake coordinated control of the asymmetric turbocharger.

[0041] See also Figure 2 , a flow chart of an engine control method disclosed in an embodiment of the present application, the method is applied to the engine controller in the above embodiment, the control method includes: Step S101: Determine a corresponding target EGR rate based on a target performance parameter of the engine.

[0042] Among them, the target performance parameters of the engine include but are not limited to engine speed, engine torque, NOx emission target, etc.

[0043] Specifically, the target performance parameter of the engine is obtained, and the target EGR rate corresponding to the target performance parameter is determined from the corresponding relationship between the preset engine performance parameter and the EGR rate.

[0044] In practical applications, the correspondence between engine performance parameters and EGR rate can be determined through bench tests based on the engine performance requirements to confirm the corresponding EGR rate and intake pressure under different engine performance parameters.

[0045] Step S102: Control the small-channel EGR valve to open.

[0046] In the present application, the small flow channel EGR valve is first controlled to open to ensure that the asymmetric turbocharger has a certain degree of asymmetry, thereby avoiding the asymmetry being too small, resulting in low operating efficiency of the small flow channel.

[0047] In actual application, the engine controller controls the opening of the small-channel EGR valve by sending an opening instruction to the small-channel EGR valve, thereby controlling the conduction of the second EGR branch where the small-channel EGR valve is located, so that the EGR flow in the second EGR branch flows to the EGR flow collection device.

[0048] Step S103: If the target EGR rate can be achieved by opening only the small-channel EGR valve, output a corresponding first target small-channel EGR valve opening.

[0049] Specifically, when only the small-channel EGR valve is opened, the EGR flow acquisition device can directly obtain the EGR flow value flowing into the second EGR branch, and send the EGR flow value to the engine controller. The engine controller can obtain the EGR rate at this time based on the EGR flow value and the engine intake flow value.

[0050] The calculation formula of EGR rate is as follows: EGR rate = EGR flow value / (EGR flow value + engine intake flow value).

[0051] The engine compares the EGR rate with the target EGR rate. If the EGR rate is equal to the target EGR rate, the engine directly outputs the corresponding target small-channel EGR valve opening.

[0052] In actual applications, the engine controller can adjust the EGR flow value in the second EGR branch by adjusting the opening of the small-channel EGR valve until the opening of the small-channel EGR valve is less than the first set maximum opening and the calculated EGR rate reaches the target EGR rate.

[0053] Step S104: If the opening of the small-channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-channel EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-channel EGR valve opening and target large-channel EGR valve opening.

[0054] Among them, the value of the first set maximum opening is determined according to actual needs and is not limited in this application.

[0055] Each time the opening of the small channel EGR valve is adjusted in the present application, it is necessary to ensure that the opening of the small channel EGR valve after adjustment is not greater than the first set maximum opening. If the opening of the small channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, it is necessary to continue to control the opening of the large channel EGR valve to increase the EGR flow value collected by the EGR flow collection device. When the engine controller determines that the large channel EGR valve is opened and reaches the target EGR rate requirement, the corresponding second target small channel EGR valve opening and target large channel EGR valve opening are output.

[0056] In summary, the present application discloses an engine control method, in which the engine has two EGR branches, the first EGR branch is connected to the large flow passage of the turbine and is provided with a large flow passage EGR valve, the second EGR branch is connected to the small flow passage of the turbine and is provided with a small flow passage EGR valve, the first EGR branch and the second EGR branch are connected to the same EGR flow acquisition device, the engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine, first controls the small flow passage EGR valve to open, if only opening the small flow passage EGR valve can achieve the target EGR rate, outputs the corresponding first target small flow passage EGR valve opening, if the opening of the small flow passage EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continues to control the large flow passage EGR valve to open until the target EGR rate is reached, and outputs the corresponding second target small flow passage EGR valve opening and the target large flow passage EGR valve opening. In the present application, the small-flow EGR valve and the large-flow EGR valve are independently controlled by the engine controller, and dual-path EGR air intake is achieved by controlling the opening of the dual-path EGR valve to fully utilize the pressure difference between the pre-turbines pressure and the intake pressure, drive the EGR to obtain a higher EGR rate, achieve the target EGR rate, and avoid selecting too small asymmetry, which causes low operating efficiency of the small flow path. At the same time, dual-path EGR air intake can also reduce pumping loss and supercharger speed, so as to reduce the supercharger bleed area, thereby reducing fuel consumption and NOx emissions.

[0057] In one embodiment, step S103 may specifically include: Controlling the small-channel EGR valve to gradually increase the opening degree from an initial opening degree according to a first preset amplitude, and obtaining a first EGR rate corresponding to each increase in the opening degree; When the first EGR rate reaches the target EGR rate and the opening of the small-channel EGR valve is less than the first set maximum opening, the corresponding first target small-channel EGR valve opening is output.

[0058] In actual application, the engine controller first controls the small-channel EGR valve to open a preset initial opening, and then gradually increases the opening according to a first preset amplitude. Each time the opening of the small-channel EGR valve increases, the EGR flow collection device sends the collected EGR flow value to the engine controller, and the engine calculates the first EGR rate corresponding to the increase in the opening. When it is determined that the first EGR rate reaches the target EGR rate and the opening of the small-channel EGR valve is less than the first set maximum opening, the corresponding first target small-channel EGR valve opening is output.

[0059] In one embodiment, step S104 may specifically include: If the opening of the small-channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, controlling the opening of the small-channel EGR valve to maintain the first set maximum opening; Controlling the large-flow-channel EGR valve to open; Controlling the large-flow EGR valve to gradually increase the opening degree from an initial opening degree according to a second preset amplitude, and obtaining a second EGR rate corresponding to each increase in the opening degree, wherein the second EGR rate is determined based on a total EGR flow rate output by the first EGR branch and the second EGR branch; When the second EGR rate reaches the target EGR rate and the opening of the large-flow-channel EGR valve is less than the second set maximum opening, the corresponding second target small-flow-channel EGR valve opening and the target large-flow-channel EGR valve opening are output.

[0060] In actual application, when the engine controller controls the opening of the small channel EGR valve to reach the first set maximum opening, and determines that the corresponding EGR rate has not reached the target EGR rate, the engine controller controls the opening of the small channel EGR valve to maintain the first set maximum opening unchanged, and continues to control the large channel EGR valve to open. The engine controller first controls the large channel EGR valve to open the preset initial opening, and then gradually increases the opening according to the second preset amplitude. Each time the opening of the large channel EGR valve increases, the EGR flow acquisition device sends the total EGR flow value of the first EGR branch and the second EGR branch collected to the engine controller, and the engine controller calculates the corresponding second EGR rate. When the engine determines that the second EGR rate reaches the target EGR rate and the opening of the large channel EGR valve is less than the second set maximum opening, the corresponding second target small channel EGR valve opening and target large channel EGR valve opening are output.

[0061] Among them, the values ​​of the first preset amplitude when regulating the small-channel EGR valve and the second preset amplitude when regulating the large-channel EGR valve are determined according to actual needs, and this application does not limit them here.

[0062] In one embodiment, the engine control method may further include: If the opening of the small-channel EGR valve reaches a first set maximum opening, the opening of the large-channel EGR valve reaches a second set maximum opening, and the corresponding EGR rate does not reach the target EGR rate, the engine is controlled to limit torque to meet the gas emission requirements of the engine.

[0063] Among them, the values ​​of the first set maximum opening and the second set maximum opening are determined according to actual needs, and this application does not limit them here.

[0064] In the present application, when the opening of the small-channel EGR valve reaches the first set maximum opening and the opening of the large-channel EGR valve reaches the second set maximum opening, when the EGR rate determined by the engine controller based on the EGR flow value collected by the EGR flow collection device still does not reach the target EGR rate, the present application directly controls the engine to execute torque limiting measures to meet the engine's gas emission requirements.

[0065] In practical applications, controlling the engine to execute torque limiting measures can reduce the amount of engine oil for controlling the engine.

[0066] In one embodiment, the engine control method may further include: Determining a corresponding target intake pressure based on a target performance parameter of the engine; The opening of the purge valve is adjusted until the intake pressure of the engine reaches the target intake pressure.

[0067] In practical applications, the intake pressure under different engine performance parameters (such as engine speed and engine torque) can be determined through bench tests according to the engine performance requirements, thereby obtaining the corresponding relationship between the engine performance parameters and the intake pressure. After obtaining the target performance parameters of the engine, the target performance parameters are compared with each engine performance parameter in the corresponding relationship between the engine performance parameters and the intake pressure to determine the corresponding target intake pressure.

[0068] like Figure 1 As shown, the bleed valve in the present application is arranged in the small flow passage of the turbine. After the bleed valve is opened, the waste in the small flow passage of the turbine can be directly discharged to the rear of the turbine, thereby reducing the speed of the supercharger.

[0069] It should be noted that the bleed valve is an electronically controlled actuator whose opening is controlled by the engine controller.

[0070] The main function of the bleed valve is to reduce the speed of the supercharger, and the opening of the bleed valve has a greater impact on the intake pressure. Therefore, the adjustment target of the bleed valve opening is to make the intake pressure reach the target intake pressure.

[0071] The control principle of the bleed valve is: the actual value of the intake pressure can be measured by a sensor and fed back to the engine controller in real time. The engine controller controls the opening of the bleed valve to meet the target intake pressure.

[0072] Corresponding to the above method embodiment, the present application also discloses an engine control device.

[0073] See also Figure 3 , a schematic diagram of the structure of an engine control device disclosed in an embodiment of the present application, the device is applied to Figure 1 The engine controller in the illustrated embodiment, the control device may include: The target EGR rate determination unit 201 is used to determine the corresponding target EGR rate based on the target performance parameter of the engine.

[0074] Specifically, the target performance parameter of the engine is obtained, and the target EGR rate corresponding to the target performance parameter is determined from the corresponding relationship between the preset engine performance parameter and the EGR rate.

[0075] In practical applications, the correspondence between engine performance parameters and EGR rate can be determined through bench tests based on the engine performance requirements to confirm the corresponding EGR rate and intake pressure under different engine performance parameters.

[0076] The opening control unit 202 is used to control the opening of the small flow channel EGR valve.

[0077] In the present application, the small flow channel EGR valve is first controlled to open to ensure that the asymmetric turbocharger has a certain degree of asymmetry, thereby avoiding the asymmetry being too small, resulting in low operating efficiency of the small flow channel.

[0078] In actual application, the engine controller controls the opening of the small-channel EGR valve by sending an opening instruction to the small-channel EGR valve, thereby controlling the conduction of the second EGR branch where the small-channel EGR valve is located, so that the EGR flow in the second EGR branch flows to the EGR flow collection device.

[0079] The first output unit 203 is used to output a corresponding first target small-channel EGR valve opening if the target EGR rate can be achieved by opening only the small-channel EGR valve.

[0080] Specifically, when only the small-channel EGR valve is opened, the EGR flow acquisition device can directly obtain the EGR flow value flowing into the second EGR branch, and send the EGR flow value to the engine controller. The engine controller can obtain the EGR rate at this time based on the EGR flow value and the engine intake flow value.

[0081] The calculation formula of EGR rate is as follows: EGR rate = EGR flow value / (EGR flow value + engine intake flow value).

[0082] The engine compares the EGR rate with the target EGR rate. If the EGR rate is equal to the target EGR rate, the engine directly outputs the corresponding target small-channel EGR valve opening.

[0083] In actual applications, the engine controller can adjust the EGR flow value in the second EGR branch by adjusting the opening of the small-channel EGR valve until the opening of the small-channel EGR valve is less than the first set maximum opening and the calculated EGR rate reaches the target EGR rate.

[0084] The second output unit 204 is used to continue controlling the large channel EGR valve to open if the opening of the small channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, until the target EGR rate is reached, and output the corresponding second target small channel EGR valve opening and target large channel EGR valve opening.

[0085] Among them, the value of the first set maximum opening is determined according to actual needs and is not limited in this application.

[0086] Each time the opening of the small channel EGR valve is adjusted in the present application, it is necessary to ensure that the opening of the small channel EGR valve after adjustment is not greater than the first set maximum opening. If the opening of the small channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, it is necessary to continue to control the opening of the large channel EGR valve to increase the EGR flow value collected by the EGR flow collection device. When the engine controller determines that the large channel EGR valve is opened and reaches the target EGR rate requirement, the corresponding second target small channel EGR valve opening and target large channel EGR valve opening are output.

[0087] In summary, the present application discloses an engine control device, in which the engine has two EGR branches, the first EGR branch is connected to the large flow passage of the turbine and is provided with a large flow passage EGR valve, the second EGR branch is connected to the small flow passage of the turbine and is provided with a small flow passage EGR valve, the first EGR branch and the second EGR branch are connected to the same EGR flow acquisition device, the engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine, first controls the small flow passage EGR valve to open, if only opening the small flow passage EGR valve can achieve the target EGR rate, outputs the corresponding first target small flow passage EGR valve opening, if the opening of the small flow passage EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continues to control the large flow passage EGR valve to open until the target EGR rate is reached, and outputs the corresponding second target small flow passage EGR valve opening and the target large flow passage EGR valve opening. In the present application, the small-flow EGR valve and the large-flow EGR valve are independently controlled by the engine controller, and dual-path EGR air intake is achieved by controlling the opening of the dual-path EGR valve to fully utilize the pressure difference between the pre-turbines pressure and the intake pressure, drive the EGR to obtain a higher EGR rate, achieve the target EGR rate, and avoid selecting too small asymmetry, which causes low operating efficiency of the small flow path. At the same time, dual-path EGR air intake can also reduce pumping loss and supercharger speed, so as to reduce the supercharger bleed area, thereby reducing fuel consumption and NOx emissions.

[0088] In one embodiment, the first output unit 203 may be specifically used for: Controlling the small-channel EGR valve to gradually increase the opening degree from an initial opening degree according to a first preset amplitude, and obtaining a first EGR rate corresponding to each increase in the opening degree; When the first EGR rate reaches the target EGR rate and the opening of the small-channel EGR valve is less than the first set maximum opening, the corresponding first target small-channel EGR valve opening is output.

[0089] In one embodiment, the second output unit 204 can be specifically used to: if the opening of the small-channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, control the opening of the small-channel EGR valve to maintain the first set maximum opening; Controlling the large-flow-channel EGR valve to open; Controlling the large-flow EGR valve to gradually increase the opening degree from an initial opening degree according to a second preset amplitude, and obtaining a second EGR rate corresponding to each increase in the opening degree, wherein the second EGR rate is determined based on a total EGR flow rate output by the first EGR branch and the second EGR branch; When the second EGR rate reaches the target EGR rate and the opening of the large-flow-channel EGR valve is less than the second set maximum opening, the corresponding second target small-flow-channel EGR valve opening and the target large-flow-channel EGR valve opening are output.

[0090] In one embodiment, the engine control device may further include: The torque limiting unit is used to control the engine to limit the torque to meet the gas emission requirements of the engine if the opening of the small-channel EGR valve reaches a first set maximum opening, the opening of the large-channel EGR valve reaches a second set maximum opening, and the corresponding EGR rate does not reach the target EGR rate.

[0091] In one embodiment, the engine control device may further include: a target intake pressure determination unit, configured to determine a corresponding target intake pressure based on the target performance parameter of the engine; The purge valve adjustment unit is used to adjust the opening of the purge valve until the intake pressure of the engine reaches the target intake pressure.

[0092] In one embodiment, the target EGR rate determination unit 201 may be specifically used to: acquiring the target performance parameter of the engine; The target EGR rate corresponding to the target performance parameter is determined from the corresponding relationship between the preset engine performance parameter and the EGR rate.

[0093] It should be noted that, for the specific working principles of each component in the device embodiment, please refer to the corresponding part of the method embodiment, which will not be repeated here.

[0094] Corresponding to the above embodiment, Figure 4 As shown, the present invention also provides an engine controller, which may include: a processor 1 and a memory 2; The processor 1 and the memory 2 communicate with each other via a communication bus 3; Processor 1, configured to execute at least one instruction; Memory 2, used to store at least one instruction; The processor 1 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0095] The memory 2 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0096] Among them, the processor executes at least one instruction to implement the steps shown in the engine control method embodiment.

[0097] Corresponding to the above-mentioned embodiment, the present application further discloses a computer storage medium, which stores at least one instruction, and when the at least one instruction is executed by a processor, the steps shown in the embodiment of the engine control method are implemented.

[0098] Computer storage media may be tangible media that may contain or store programs for use by or in conjunction with an instruction execution system, device, or apparatus. Computer storage media may be machine-readable signal media or machine-readable storage media. Computer storage media may include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media may include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0099] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0100] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0101] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An engine control method, characterized in that: Applied to an engine controller, the engine has two exhaust gas recirculation EGR branches, the first EGR branch is connected to the turbine large flow channel and is provided with a large flow channel EGR valve, the second EGR branch is connected to the turbine small flow channel and is provided with a small flow channel EGR valve, the first EGR branch and the second EGR branch are connected to the same EGR flow collection device, and the engine control method includes: Determining a corresponding target EGR rate based on a target performance parameter of the engine; Controlling the small flow channel EGR valve to open; If the target EGR rate can be achieved by opening only the small-channel EGR valve, outputting a corresponding first target small-channel EGR valve opening; If the opening of the small-channel EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-channel EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-channel EGR valve opening and target large-channel EGR valve opening.

2. The engine control method according to claim 1, characterized in that: If the target EGR rate can be achieved by opening only the small-channel EGR valve, outputting a corresponding first target small-channel EGR valve opening degree includes: Controlling the small-channel EGR valve to gradually increase the opening degree from an initial opening degree according to a first preset amplitude, and obtaining a first EGR rate corresponding to each increase in the opening degree; When the first EGR rate reaches the target EGR rate and the opening of the small-channel EGR valve is less than the first set maximum opening, the corresponding first target small-channel EGR valve opening is output.

3. The engine control method according to claim 1 or 2, characterized in that: If the opening of the small-flow passage EGR valve reaches the first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-flow passage EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-flow passage EGR valve opening and target large-flow passage EGR valve opening, including: If the opening of the small-channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, controlling the opening of the small-channel EGR valve to maintain the first set maximum opening; Controlling the large-flow-channel EGR valve to open; Controlling the large-flow EGR valve to gradually increase the opening degree from an initial opening degree according to a second preset amplitude, and obtaining a second EGR rate corresponding to each increase in the opening degree, wherein the second EGR rate is determined based on a total EGR flow rate output by the first EGR branch and the second EGR branch; When the second EGR rate reaches the target EGR rate and the opening of the large-flow-channel EGR valve is less than the second set maximum opening, the corresponding second target small-flow-channel EGR valve opening and the target large-flow-channel EGR valve opening are output.

4. The engine control method according to claim 1, characterized in that: Also includes: If the opening of the small-channel EGR valve reaches a first set maximum opening, the opening of the large-channel EGR valve reaches a second set maximum opening, and the corresponding EGR rate does not reach the target EGR rate, the engine is controlled to limit torque to meet the gas emission requirements of the engine.

5. The engine control method according to claim 1 or 4, characterized in that: Also includes: determining a corresponding target intake pressure based on the target performance parameter of the engine; The opening of the purge valve is adjusted until the intake pressure of the engine reaches the target intake pressure.

6. The engine control method according to claim 1, characterized in that: The determining of the corresponding target EGR rate based on the target performance parameter of the engine includes: acquiring the target performance parameter of the engine; The target EGR rate corresponding to the target performance parameter is determined from the corresponding relationship between the preset engine performance parameter and the EGR rate.

7. An engine control device, characterized in that: Applied to an engine controller, the engine has two exhaust gas recirculation EGR branches, the first EGR branch is connected to the turbine large flow channel and is provided with a large flow channel EGR valve, the second EGR branch is connected to the turbine small flow channel and is provided with a small flow channel EGR valve, the first EGR branch and the second EGR branch are connected to the same EGR flow collection device, and the engine control device includes: a target EGR rate determination unit, configured to determine a corresponding target EGR rate based on a target performance parameter of the engine; An opening control unit, used for controlling the opening of the small flow channel EGR valve; a first output unit, configured to output a corresponding first target small-channel EGR valve opening if the target EGR rate can be achieved by opening only the small-channel EGR valve; The second output unit is used to continue controlling the large channel EGR valve to open if the opening of the small channel EGR valve reaches a first set maximum opening and the corresponding EGR rate does not reach the target EGR rate, until the target EGR rate is reached, and output the corresponding second target small channel EGR valve opening and target large channel EGR valve opening.

8. An engine controller, characterized in that: The engine controller includes: a memory and a processor; The memory is used to store at least one instruction; The processor is used to execute the at least one instruction to implement the engine control method as described in any one of claims 1 to 6.

9. A computer storage medium, characterized in that: The computer storage medium stores at least one instruction, and when the at least one instruction is executed by the processor, the engine control method according to any one of claims 1 to 6 is implemented.

10. An engine, characterized in that: include: A first engine cylinder set, a second engine cylinder set, a first exhaust pipe, a second exhaust pipe, an intake pipe, a first EGR branch, a second EGR branch, an EGR flow collection device, an asymmetric turbocharger, a purge valve, an intercooler, and an engine controller as claimed in claim 8; The input end of the first engine cylinder set is connected to the intake pipe, and the output end is connected to the first exhaust pipe. A large flow channel of the turbine is between the first exhaust pipe and the turbine of the asymmetric turbocharger. The large flow channel of the turbine is connected to the EGR flow collection device through the first EGR branch. The first EGR branch is provided with a large flow channel EGR valve. The input end of the second engine cylinder set is connected to the intake pipe, and the output end is connected to the second exhaust pipe. A small turbine flow passage is formed between the second exhaust pipe and the compressor of the asymmetric turbocharger. The small turbine flow passage is connected to the EGR flow collection device through the second EGR branch. The second EGR branch is provided with a small flow passage EGR valve. The EGR flow collection device is connected to the intake pipe; The intercooler is arranged between the compressor and the intake pipe; The air release valve is arranged at the exhaust end of the turbine small flow passage and the asymmetric turbocharger; The engine controller is respectively connected to the EGR flow collection device, the large-channel EGR valve, the small-channel EGR valve and the air release valve, and is used to control the opening of the large-channel EGR valve, the opening of the small-channel EGR valve and the air release valve.

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