An engine control method and related device

Abstract

The present invention discloses an engine control method and related device, relating to the field of engines. The engine has two EGR branches, which are respectively connected to the large flow channel and the small flow channel of the turbine. The engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine, controls the opening of the small flow channel EGR valve. If only opening the small flow channel EGR valve can reach the target EGR rate, the corresponding first target opening of the small flow channel EGR valve is output. 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, the large flow channel EGR valve is controlled to open to reach the target EGR rate, and the corresponding second target opening of the small flow channel EGR valve and the target opening of the large flow channel EGR valve are output. This application realizes dual-path EGR gas intake by controlling the opening of the dual-path EGR valve, achieving the reduction of pumping loss and turbocharger speed while increasing the EGR rate, thereby reducing fuel consumption and NOx emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and more specifically, to an engine control method and related device. Background Art

[0002] When an 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 adopted. The asymmetric turbocharger designs the turbine flow passage into two flow passages, a large flow passage and a small flow passage. The two flow passages are set with an appropriate degree of asymmetry according to the engine requirements. The large flow passage has a large flow capacity and a low pressure in front of the turbine, which can reduce the high-speed pumping loss; the small flow passage has a small flow capacity and a high pressure in front of the turbine, realizing introducing a sufficient EGR (Exhaust Gas Recycling) flow into the engine intake manifold at low speeds.

[0003] The selection of the degree of asymmetry of the asymmetric turbocharger has a great influence on the EGR rate, turbocharger speed, NOx emissions, and fuel consumption of the entire engine operating conditions. If the degree of asymmetry increases, the corresponding EGR rate decreases, resulting in the opposite of the original purpose of selecting the asymmetric turbocharger; if the degree of asymmetry is too small, the flow capacity of the small flow passage will be too small, resulting in a decrease in the operating efficiency of the asymmetric turbocharger, an increase in pumping loss and turbocharger speed, serious deterioration of fuel consumption, and an increase in NOx (nitrogen oxides) emissions.

[0004] Therefore, how to provide an engine control method that, in cooperation with an asymmetric turbocharger, realizes increasing the EGR rate while reducing pumping loss 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 device to realize increasing the EGR rate while reducing pumping loss and turbocharger speed, 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 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 collection device. The engine control method includes:

[0007] Determining a corresponding target EGR rate based on the target performance parameters of the engine;

[0008] Controlling the small flow passage EGR valve to open;

[0009] If only opening the small-channel EGR valve can achieve the target EGR rate, output the corresponding first target opening of the small-channel EGR valve.

[0010] 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 opening of the small-channel EGR valve and the target opening of the large-channel EGR valve.

[0011] Optionally, the step of if only opening the small-channel EGR valve can achieve the target EGR rate, output the corresponding first target opening of the small-channel EGR valve, includes:

[0012] Control the small-channel EGR valve to gradually increase the opening from the initial opening at a first preset amplitude, and obtain the corresponding first EGR rate after each increase in the opening.

[0013] 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, output the corresponding first target opening of the small-channel EGR valve.

[0014] Optionally, the step of 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 opening of the small-channel EGR valve and the target opening of the large-channel EGR valve, includes:

[0015] 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, control the opening of the small-channel EGR valve to maintain the first set maximum opening.

[0016] Control the large-channel EGR valve to open.

[0017] Control the large-channel EGR valve to gradually increase the opening from the initial opening at a second preset amplitude, and obtain the corresponding second EGR rate after each increase in the opening, where the second EGR rate is determined based on the total EGR flow output by the first EGR branch and the second EGR branch.

[0018] When 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, output the corresponding second target opening of the small-channel EGR valve and the target opening of the large-channel EGR valve.

[0019] Optionally, it further includes:

[0020] When the opening degree of the small-flow EGR valve reaches the first set maximum opening degree, the opening degree of the large-flow EGR valve reaches the second set maximum opening degree, and the corresponding EGR rate does not reach the target EGR rate, control the engine to limit the torque to meet the gas emission requirements of the engine.

[0021] Optionally, it further includes:

[0022] Determine the corresponding target intake pressure based on the target performance parameters of the engine;

[0023] Adjust the opening degree of the bleed valve until the intake pressure of the engine reaches the target intake pressure.

[0024] Optionally, the determining the corresponding target EGR rate based on the target performance parameters of the engine includes:

[0025] Obtain the target performance parameters of the engine;

[0026] Determine the target EGR rate corresponding to the target performance parameters from the corresponding relationship between the preset engine performance parameters and the EGR rate.

[0027] 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 the large flow path of the turbine and is provided with a large-flow EGR valve. The second EGR branch is connected to the small flow path of the turbine and is provided with a small-flow 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:

[0028] A target EGR rate determination unit for determining the corresponding target EGR rate based on the target performance parameters of the engine;

[0029] An opening control unit for controlling the opening of the small-flow EGR valve;

[0030] A first output unit for outputting the corresponding first target small-flow EGR valve opening degree if only opening the small-flow EGR valve can reach the target EGR rate;

[0031] A second output unit for, if the opening degree of the small-flow EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, continue to control the opening of the large-flow EGR valve until the target EGR rate is reached, and output the corresponding second target small-flow EGR valve opening degree and target large-flow EGR valve opening degree.

[0032] An engine controller, the engine controller includes: a memory and a processor;

[0033] The memory is used to store at least one instruction;

[0034] The processor is used to execute the at least one instruction to implement the engine control method described above.

[0035] 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.

[0036] An engine includes: 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 acquisition device, an asymmetric turbocharger, a bleed valve, an intercooler, and the engine controller described above;

[0037] 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. Between the first exhaust pipe and the turbine of the asymmetric turbocharger is a large turbine flow passage, and the large turbine flow passage is connected to the EGR flow acquisition device through the first EGR branch, and a large flow passage EGR valve is arranged on the first EGR branch;

[0038] 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. Between the second exhaust pipe and the compressor of the asymmetric turbocharger is a small turbine flow passage, and the small turbine flow passage is connected to the EGR flow acquisition device through the second EGR branch, and a small flow passage EGR valve is arranged on the second EGR branch;

[0039] The EGR flow acquisition device is connected to the intake pipe;

[0040] The intercooler is arranged between the compressor and the intake pipe;

[0041] The bleed valve is arranged at the exhaust end of the small turbine flow passage and the asymmetric turbocharger;

[0042] The engine controller is respectively connected to the EGR flow acquisition device, the large flow passage EGR valve, the small flow passage EGR valve, and the bleed valve, and is used to control the opening degrees of the large flow passage EGR valve, the small flow passage EGR valve, and the bleed valve.

[0043] As can be seen from the above technical solutions, the present invention discloses an engine control method and related devices. 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 rate acquisition device. The engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine. First, it controls the small flow channel EGR valve to open. If only opening the small flow channel EGR valve can reach the target EGR rate, it 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, it 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 target large flow channel EGR valve opening. In this application, the small flow channel EGR valve and the large flow channel EGR valve are separately controlled by the engine controller. By controlling the opening of the dual EGR valves, dual EGR air intake is achieved, so as to make full use of the pressure difference between the pressure in front of the turbine and the intake pressure, drive the EGR to obtain a higher EGR rate, reach the target EGR rate, and avoid choosing too small an asymmetry degree, resulting in low operating efficiency of the small flow channel. At the same time, dual EGR air intake can also reduce the pumping loss and the speed of the supercharger, so as to reduce the supercharger bleed area, thereby reducing fuel consumption and NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the disclosed drawings.

[0045] Figure 1 It is a schematic diagram of a dual EGR air intake structure in an engine with an asymmetric turbocharger disclosed in an embodiment of the present invention;

[0046] Figure 2 It is a flowchart of an engine control method disclosed in an embodiment of the present invention;

[0047] Figure 3 It is a schematic diagram of the structure of an engine control device disclosed in an embodiment of the present invention;

[0048] Figure 4 It is a schematic diagram of the structure of an engine controller disclosed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] Explanations of related terms are as follows:

[0050] EGR (Exhaust Gas Recirculation) refers to the technology that, after combustion in an automotive internal combustion engine, introduces a portion of the exhaust gas into the intake for re-combustion, which can reduce nitrogen oxides (NOx) in the exhaust gas and improve fuel economy.

[0051] The asymmetry refers to the ratio of the flow area of the small turbine passage to that of the large turbine passage. This parameter directly affects the flow distribution in the turbine passage and has a significant impact on parameters such as the EGR rate, pumping loss, and fuel consumption.

[0052] To meet the requirements of continuously upgraded engine emission regulations, the NOx emissions of the internal combustion engine in the engine are required to be low. To achieve this requirement, the EGR technology is often adopted. The 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, a smaller turbine is required, but this will result in excessive pressure before the turbine at medium and high engine speeds, increased pumping loss, and deteriorated fuel consumption. Using an asymmetric turbocharger can effectively solve the pumping loss at high engine speeds and the problem of turbocharger overspeed. However, if the asymmetry is too small, the flow capacity of the small passage will be too small, resulting in a decrease in the operating efficiency of the asymmetric turbocharger, an increase in pumping loss and turbocharger speed, serious deterioration of fuel consumption, and an increase in NOx emissions.

[0053] To solve this problem, the present application provides an engine control method. By using a dual-path EGR gas intake method for an engine with an asymmetric turbocharger and matching the engine with the asymmetric turbocharger, while increasing the EGR rate, the pumping loss and turbocharger speed are reduced, thereby reducing fuel consumption and NOx emissions.

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] See Figure 1 , a schematic diagram of a dual-path EGR gas intake structure in an engine with an asymmetric turbocharger disclosed in the embodiments of the present application. The engine includes: the first engine cylinder set, the second engine cylinder set, the first exhaust pipe 11, the second exhaust pipe 12, the intake pipe 13, the first EGR branch 14, the second EGR branch 15, the EGR flow acquisition device 16, the asymmetric turbocharger 17, the wastegate valve 18, the intercooler 19, and the engine controller ( Figure 1 not shown in

[0056] In practical applications, both the first engine cylinder set and the second engine cylinder set include multiple engine cylinders. For example, Figure 1 in Figure 1 , 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.

[0057] 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. Between the first exhaust pipe 11 and the turbine of the asymmetric turbocharger 17 is a large turbine flow passage. The large turbine flow passage is connected to the EGR flow rate acquisition device 16 through the first EGR branch 14. Among them, a large flow passage EGR valve 141 is provided on the first EGR branch 14.

[0058] In this application, a first EGR cooler is also provided on the first EGR branch 14.

[0059] Preferably, the EGR flow rate acquisition device 16 can be an EGR flowmeter.

[0060] 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. Between the second exhaust pipe 12 and the compressor of the asymmetric turbocharger 17 is a small turbine flow passage. The small turbine flow passage is connected to the EGR flow rate acquisition device 16 through the second EGR branch 15. A small flow passage EGR valve 151 is provided on the second EGR branch 15.

[0061] In this application, a second EGR cooler is also provided on the second EGR branch 15.

[0062] It should be particularly noted that when only the large flow passage EGR valve 141 provided on the first EGR branch 14 is opened, and the small flow passage EGR valve 151 provided on the second EGR branch 15 is not opened, the EGR flow rate value collected by the EGR flow rate acquisition device 16 is the EGR flow rate value on the first EGR branch 14.

[0063] When both the large flow passage EGR valve 141 provided on the first EGR branch 14 and the small flow passage EGR valve 151 provided on the second EGR branch 15 are opened, the EGR flow rate value collected by the EGR flow rate acquisition device 16 is the sum of the EGR flow rate value on the first EGR branch 14 and the EGR flow rate value on the second EGR branch 15.

[0064] In this application, the input end of the EGR flow rate acquisition device 16 is respectively connected to the first EGR branch 14 and the second EGR branch 15, and the output end of the EGR flow rate acquisition device 16 is connected to the intake pipe 13.

[0065] The intercooler 19 is arranged between the compressor of the asymmetric turbocharger 17 and the intake pipe 13.

[0066] The bleed valve 18 is arranged at the small flow passage of the turbine and the exhaust end of the asymmetric turbocharger 17.

[0067] The engine controller is respectively connected to the EGR flow acquisition device 16, the large flow passage EGR valve, the small flow passage EGR valve and the bleed valve, and is used to control the opening degrees of the large flow passage EGR valve, the small flow passage EGR valve and the bleed valve.

[0068] In this application, a small flow passage of the turbine and a large flow passage of the turbine are respectively connected to an EGR branch, that is, the large flow passage of the turbine is connected to the first EGR branch 14, and the small flow passage of the turbine is connected to the second EGR branch 15. The small flow passage establishes a high expansion ratio and has strong EGR driving ability. The EGR rate driving ability of the large flow passage of the turbine is relatively weak and is mainly used to provide sufficient air flow. The large flow passage EGR valve 141 on the first EGR branch 14 and the small flow passage EGR valve 151 on the second EGR branch 15 are separately controlled by the engine controller. The two-way EGR can make full use of the pressure difference between the pre-turbine pressure and the intake pressure of the large and small flow passages to drive the EGR, meet the higher NOx emission requirements, and at the same time can reduce the turbocharger speed.

[0069] Among them, the high expansion ratio means that the ratio of the pre-turbine pressure to the post-turbine pressure of the small flow passage of the turbine is large.

[0070] The bleed valve 18 is on the small flow passage of the turbine. After the bleed valve 18 is opened, the exhaust gas of the small flow passage of the turbine can be directly discharged to the post-turbine, thereby reducing the turbocharger speed. The bleed valve is an electronically controlled actuator, and its opening degree is controlled by the engine controller.

[0071] In order to enable an engine with an asymmetric turbocharger to obtain better performance, for Figure 1 the dual-path EGR air intake structure in the engine with an asymmetric turbocharger shown, this application provides an engine control method for realizing the coordinated control of the dual-path EGR air intake of the asymmetric turbocharger.

[0072] See Figure 2 , a flowchart of an engine control method disclosed in an embodiment of this application. This method is applied to the engine controller in the above embodiment, and the control method includes:

[0073] Step S101, determining a corresponding target EGR rate based on the target performance parameters of the engine.

[0074] Among them, the target performance parameters of the engine include but are not limited to engine speed, engine torque, NOx emission target, etc.

[0075] Specifically, obtain the target performance parameters of the engine, and determine the target EGR rate corresponding to the target performance parameters from the corresponding relationship between the preset engine performance parameters and the EGR rate.

[0076] In practical applications, the corresponding relationship between the engine performance parameters and the EGR rate can be confirmed by bench tests according to the performance requirements of the engine, so as to obtain the EGR rate and intake pressure corresponding to different engine performance parameters.

[0077] Step S102: Control the small-channel EGR valve to open.

[0078] In this application, first control the small-channel EGR valve to open to ensure that the asymmetric turbocharger has a certain degree of asymmetry, and avoid too small a selection of the degree of asymmetry, resulting in low operating efficiency of the small channel.

[0079] In practical applications, the engine controller controls the small-channel EGR valve to open by sending an opening command to the small-channel EGR valve, thereby controlling the second EGR branch where the small-channel EGR valve is located to conduct, so that the EGR flow in the second EGR branch flows to the EGR flow collection device.

[0080] Step S103: If only opening the small-channel EGR valve can reach the target EGR rate, output the corresponding first target small-channel EGR valve opening.

[0081] Specifically, when only the small-channel EGR valve is opened, the EGR flow collection device can directly obtain the EGR flow value flowing into the second EGR branch and send the EGR flow value to the engine controller. Based on the EGR flow value and the engine intake air flow value, the engine controller can obtain the EGR rate at this time.

[0082] The calculation formula of the EGR rate is as follows:

[0083] EGR rate = EGR flow value / (EGR flow value + engine intake air flow value).

[0084] The engine compares this 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.

[0085] In practical 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.

[0086] Step S104: If the opening degree of the small-channel EGR valve reaches the first set maximum opening degree 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 opening degree of the small-channel EGR valve and the target opening degree of the large-channel EGR valve.

[0087] Among them, the value of the first set maximum opening degree is determined according to actual needs, and this application does not make any limitations here.

[0088] Each time this application adjusts the opening degree of the small-channel EGR valve, it is necessary to ensure that the adjusted opening degree of the small-channel EGR valve is not greater than the first set maximum opening degree. If the opening degree of the small-channel EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, it is necessary to continue to control the large-channel EGR valve to open 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 the target EGR rate requirement is met, output the corresponding second target opening degree of the small-channel EGR valve and the target opening degree of the large-channel EGR valve at this time.

[0089] In summary, this application discloses an engine control method. The engine in this application has two EGR branches. The first EGR branch is connected to the large channel of the turbine and is provided with a large-channel EGR valve. The second EGR branch is connected to the small channel of the turbine and is provided with a small-channel EGR valve. The first EGR branch and the second EGR branch are connected to the same EGR flow collection device. The engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine. First, control the small-channel EGR valve to open. If only opening the small-channel EGR valve can reach the target EGR rate, output the corresponding first target opening degree of the small-channel EGR valve. If the opening degree of the small-channel EGR valve reaches the first set maximum opening degree 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 opening degree of the small-channel EGR valve and the target opening degree of the large-channel EGR valve. In this application, the small-channel EGR valve and the large-channel EGR valve are independently controlled by the engine controller. By controlling the opening degrees of the dual EGR valves, dual EGR gas intake is realized to make full use of the pressure difference between the pre-turbine pressure and the intake pressure, drive the EGR to obtain a higher EGR rate, reach the target EGR rate, and avoid too small an asymmetry selection, resulting in low operating efficiency of the small channel. At the same time, dual EGR gas intake can also reduce the pumping loss and the turbocharger speed to reduce the turbocharger bleed area, thereby reducing fuel consumption and NOx emissions.

[0090] In one embodiment, step S103 may specifically include:

[0091] Control the small-channel EGR valve to start from the initial opening degree, gradually increase the opening degree according to the first preset amplitude, and obtain the corresponding first EGR rate after each increase in the opening degree;

[0092] When the first EGR rate reaches the target EGR rate and the opening degree of the small-channel EGR valve is less than the first set maximum opening degree, output the corresponding first target small-channel EGR valve opening degree.

[0093] In practical applications, the engine controller first controls the small-channel EGR valve to open to a preset initial opening degree, and then gradually increases the opening degree according to the first preset amplitude. After each increase in the opening degree of the small-channel EGR valve, the EGR flow rate acquisition device sends the collected EGR flow rate value to the engine controller, and the engine calculates the corresponding first EGR rate after the increase in the opening degree. When it is determined that the first EGR rate reaches the target EGR rate and the opening degree of the small-channel EGR valve is less than the first set maximum opening degree, output the corresponding first target small-channel EGR valve opening degree.

[0094] In one embodiment, step S104 may specifically include:

[0095] If the opening degree of the small-channel EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, control the opening degree of the small-channel EGR valve to maintain the first set maximum opening degree;

[0096] Control the large-channel EGR valve to open;

[0097] Control the large-channel EGR valve to start from the initial opening degree, gradually increase the opening degree according to the second preset amplitude, and obtain the corresponding second EGR rate after each increase in the opening degree, where the second EGR rate is determined based on the total EGR flow rate output by the first EGR branch and the second EGR branch;

[0098] When the second EGR rate reaches the target EGR rate and the opening degree of the large-channel EGR valve is less than the second set maximum opening degree, output the corresponding second target small-channel EGR valve opening degree and the target large-channel EGR valve opening degree.

[0099] In practical applications, when the engine controller controls the opening degree of the small-channel EGR valve to reach the first set maximum opening degree and determines that the corresponding EGR rate does not reach the target EGR rate, the engine controller controls the opening degree of the small-channel EGR valve to remain unchanged at the first set maximum opening degree and continues to control the large-channel EGR valve to open. The engine controller first controls the large-channel EGR valve to open a preset initial opening degree, and then gradually increases the opening degree according to a second preset amplitude. After each increase in the opening degree of the large-channel EGR valve, the EGR flow rate acquisition device sends the total EGR flow rate 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 degree of the large-channel EGR valve is less than the second set maximum opening degree, it outputs the corresponding second target opening degree of the small-channel EGR valve and the target opening degree of the large-channel EGR valve.

[0100] Among them, the value of the first preset amplitude when regulating the small-channel EGR valve and the value of 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.

[0101] In one embodiment, the engine control method may further include:

[0102] If the opening degree of the small-channel EGR valve reaches the first set maximum opening degree, the opening degree of the large-channel EGR valve reaches the second set maximum opening degree, and the corresponding EGR rate does not reach the target EGR rate, control the engine to limit the torque to meet the gas emission requirements of the engine.

[0103] Among them, the values of the first set maximum opening degree and the second set maximum opening degree are determined according to actual needs, and this application does not limit them here.

[0104] In this application, when the opening degree of the small-channel EGR valve reaches the first set maximum opening degree and at the same time the opening degree of the large-channel EGR valve reaches the second set maximum opening degree, and the EGR rate determined by the engine controller according to the EGR flow rate value collected by the EGR flow rate acquisition device still does not reach the target EGR rate, this application directly controls the engine to execute the torque limiting measure to meet the gas emission requirements of the engine.

[0105] In practical applications, controlling the engine to execute the torque limiting measure may be to control the engine to reduce the engine fuel quantity.

[0106] In one embodiment, the engine control method may further include:

[0107] Determine the corresponding target intake pressure based on the target performance parameters of the engine;

[0108] Adjust the opening degree of the bleed valve until the intake pressure of the engine reaches the target intake pressure.

[0109] In practical applications, according to the performance requirements of the engine, the intake pressure at different engine performance parameters (such as engine speed, engine torque) can be determined through bench tests, so as to obtain the corresponding relationship between the engine performance parameters and the intake pressure. After obtaining the target performance parameters of the engine, compare the target performance parameters with each engine performance parameter in the corresponding relationship between the engine performance parameters and the intake pressure, and the corresponding target intake pressure can be determined.

[0110] As Figure 1 shown, the bleed valve in this application is arranged in the small flow channel of the turbine. After the bleed valve is opened, the waste gas in the small flow channel of the turbine can be directly discharged to the rear of the turbine, thereby reducing the supercharger speed.

[0111] It should be noted that, as an electronically controlled actuator, the bleed valve is controlled by the engine controller for its opening degree.

[0112] The main function of the bleed valve is to reduce the supercharger speed, and the opening degree of the bleed valve has a great influence on the intake pressure. Therefore, the adjustment target of the bleed valve opening degree is that the intake pressure reaches the target intake pressure.

[0113] 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, and the engine controller controls the opening degree of the bleed valve to meet the target intake pressure.

[0114] Corresponding to the above method embodiment, the present application also discloses an engine control device.

[0115] See Figure 3 This is a schematic structural diagram 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 embodiment shown, and the control device may include:

[0116] A target EGR rate determination unit 201, configured to determine a corresponding target EGR rate based on the target performance parameters of the engine.

[0117] Specifically, obtain the target performance parameters of the engine, and determine the target EGR rate corresponding to the target performance parameters from the corresponding relationship between the preset engine performance parameters and the EGR rate.

[0118] In practical applications, the corresponding relationship between the engine performance parameters and the EGR rate can be used to confirm the corresponding EGR rate and intake pressure under different engine performance parameters according to the performance requirements of the engine through bench tests.

[0119] An opening control unit 202, configured to control the opening of the small flow channel EGR valve.

[0120] In this application, the small-channel EGR valve is first controlled to open to ensure that the asymmetric turbocharger has a certain degree of asymmetry, avoiding a too small degree of asymmetry, which may result in low operating efficiency of the small channel.

[0121] In practical applications, the engine controller controls the small-channel EGR valve to open by sending an opening command to the small-channel EGR valve, thereby controlling the second EGR branch where the small-channel EGR valve is located to conduct, so that the EGR flow in the second EGR branch flows to the EGR flow acquisition device.

[0122] The first output unit 203 is configured to output the corresponding first target small-channel EGR valve opening degree if only opening the small-channel EGR valve can achieve the target EGR rate.

[0123] Specifically, after 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. Based on the EGR flow value and the engine intake air flow value, the engine controller can obtain the EGR rate at this time.

[0124] The calculation formula of the EGR rate is as follows:

[0125] EGR rate = EGR flow value / (EGR flow value + engine intake air flow value).

[0126] 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 degree.

[0127] In practical applications, the engine controller can adjust the EGR flow value in the second EGR branch by adjusting the opening degree of the small-channel EGR valve until the opening degree of the small-channel EGR valve is less than the first set maximum opening degree and the calculated EGR rate reaches the target EGR rate.

[0128] The second output unit 204 is configured to continue to control the large-channel EGR valve to open if the opening degree of the small-channel EGR valve reaches the first set maximum opening degree 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 degree and target large-channel EGR valve opening degree.

[0129] Among them, the value of the first set maximum opening degree is determined according to actual needs, and this application does not limit it here.

[0130] Each time the opening degree of the small-flow EGR valve is adjusted in this application, it is necessary to ensure that the opening degree of the adjusted small-flow EGR valve is not greater than the first set maximum opening degree. If the opening degree of the small-flow EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, it is necessary to continue to control the large-flow EGR valve to open and increase the EGR flow value collected by the EGR flow collection device. When the engine controller determines that the large-flow EGR valve is opened and the target EGR rate requirement is reached, the corresponding second target small-flow EGR valve opening degree and the target large-flow EGR valve opening degree at this time are output.

[0131] In summary, this application discloses an engine control device. The engine in this application has two EGR branches. The first EGR branch is connected to the large flow path of the turbine and is provided with a large-flow EGR valve. The second EGR branch is connected to the small flow path of the turbine and is provided with a small-flow EGR valve. The first EGR branch and the second EGR branch are connected to the same EGR flow collection device. The engine controller determines the corresponding target EGR rate based on the target performance parameters of the engine. First, it controls the small-flow EGR valve to open. If only opening the small-flow EGR valve can reach the target EGR rate, the corresponding first target small-flow EGR valve opening degree is output. If the opening degree of the small-flow EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, continue to control the large-flow EGR valve to open until the target EGR rate is reached, and output the corresponding second target small-flow EGR valve opening degree and the target large-flow EGR valve opening degree. In this application, the small-flow EGR valve and the large-flow EGR valve are independently controlled by the engine controller. By controlling the opening degrees of the dual EGR valves, dual EGR air intake is realized to make full use of the pressure difference between the pressure in front of the turbine and the intake pressure, drive the EGR to obtain a higher EGR rate, reach the target EGR rate, and avoid too small an asymmetry selection, resulting in low operating efficiency of the small flow path. At the same time, dual EGR air intake can also reduce the pumping loss and the supercharger speed, so as to reduce the supercharger bleed area, thereby reducing fuel consumption and NOx emissions.

[0132] In one embodiment, the first output unit 203 can specifically be used for:

[0133] Control the small-flow EGR valve to start from the initial opening degree and gradually increase the opening degree according to the first preset amplitude, and obtain the corresponding first EGR rate after each increase in the opening degree;

[0134] When the first EGR rate reaches the target EGR rate and the opening degree of the small-flow EGR valve is less than the first set maximum opening degree, output the corresponding first target small-flow EGR valve opening degree.

[0135] In one embodiment, the second output unit 204 may specifically be configured to: if the opening degree of the small flow path EGR valve reaches a first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, control the opening degree of the small flow path EGR valve to maintain the first set maximum opening degree;

[0136] Control the large flow path EGR valve to open;

[0137] Control the large flow path EGR valve to gradually increase the opening degree from the initial opening degree at a second preset amplitude, and obtain the corresponding second EGR rate after each increase in the opening degree, where the second EGR rate is determined based on the total EGR flow output by the first EGR branch and the second EGR branch;

[0138] When the second EGR rate reaches the target EGR rate and the opening degree of the large flow path EGR valve is less than the second set maximum opening degree, output the corresponding second target small flow path EGR valve opening degree and the target large flow path EGR valve opening degree.

[0139] In one embodiment, the engine control device may further include:

[0140] A torque limiting unit, configured to control the engine to limit torque when the opening degree of the small flow path EGR valve reaches the first set maximum opening degree, the opening degree of the large flow path EGR valve reaches the second set maximum opening degree, and the corresponding EGR rate does not reach the target EGR rate, so as to meet the gas emission requirements of the engine.

[0141] In one embodiment, the engine control device may further include:

[0142] A target intake pressure determination unit, configured to determine a corresponding target intake pressure based on the target performance parameters of the engine;

[0143] A bleed valve adjustment unit, configured to adjust the opening degree of the bleed valve until the intake pressure of the engine reaches the target intake pressure.

[0144] In one embodiment, the target EGR rate determination unit 201 may specifically be configured to:

[0145] Obtain the target performance parameters of the engine;

[0146] Determine the target EGR rate corresponding to the target performance parameters from the corresponding relationship between the preset engine performance parameters and the EGR rate.

[0147] It should be noted that for the specific working principles of the components in the device embodiment, please refer to the corresponding parts of the method embodiment, which will not be elaborated here.

[0148] Corresponding to the above embodiment, asFigure 4 As shown in Figure 4 , the present invention also provides an engine controller, which may include: a processor 1 and a memory 2;

[0149] Wherein, the processor 1 and the memory 2 communicate with each other through a communication bus 3;

[0150] The processor 1 is configured to execute at least one instruction;

[0151] The memory 2 is configured to store at least one instruction;

[0152] 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.

[0153] The memory 2 may include a high-speed RAM memory, and may also include non-volatile memory, such as at least one disk memory.

[0154] Wherein, the processor executes at least one instruction to implement the steps shown in the embodiments of the engine control method.

[0155] Corresponding to the above embodiments, the present application also 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 embodiments of the engine control method are implemented.

[0156] The computer storage medium may be a tangible medium that may contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer storage medium may be a machine-readable signal medium or a machine-readable storage medium. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0157] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising said element.

[0158] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0159] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can 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 broadest 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 at least includes: a first engine cylinder bank, a second engine cylinder bank, a first exhaust pipe, a second exhaust pipe, a first EGR branch, a second EGR branch, an EGR flow acquisition device, an asymmetric turbocharger, a wastegate valve, and an engine controller; the engine has two exhaust gas recirculation (EGR) branches; The output end of the first engine cylinder bank is connected to the first exhaust pipe. Between the first exhaust pipe and the turbine of the asymmetric turbocharger is a large turbine flow passage. The large turbine flow passage is connected to the EGR flow acquisition device through the first EGR branch. A large flow passage EGR valve is provided on the first EGR branch; a first EGR cooler is provided on the first EGR branch; The output end of the second engine cylinder bank is connected to the second exhaust pipe. Between the second exhaust pipe and the compressor of the asymmetric turbocharger is a small turbine flow passage. The small turbine flow passage is connected to the EGR flow acquisition device through the second EGR branch. A small flow passage EGR valve is provided on the second EGR branch; a second EGR cooler is provided on the second EGR branch; The wastegate valve is provided between the small turbine flow passage and the exhaust end of the asymmetric turbocharger; the engine control method includes: Determine a corresponding target EGR rate based on the target performance parameters of the engine; Control the small flow passage EGR valve to open; Control the small flow passage EGR valve to gradually increase the opening degree from the initial opening degree at a first preset amplitude. After each increase in the opening degree, control the EGR flow acquisition device to collect the EGR flow value flowing into the second EGR branch, and obtain the EGR flow value collected by the EGR flow acquisition device. Based on the EGR flow value and the engine intake air flow value, obtain the corresponding first EGR rate after each increase in the opening degree; When the first EGR rate reaches the target EGR rate and the opening degree of the small flow passage EGR valve is less than the first set maximum opening degree, output the corresponding first target small flow passage EGR valve opening degree; If the opening degree of the small flow passage EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, control the opening degree of the small flow passage EGR valve to maintain the first set maximum opening degree; Control the large flow passage EGR valve to open; Control the large flow passage EGR valve to gradually increase the opening degree from the initial opening degree at a second preset amplitude. After each increase in the opening degree of the large flow passage EGR valve, control the EGR flow acquisition device to collect the total EGR flow value of the first EGR branch and the second EGR branch. Based on the total EGR flow value and the engine intake air flow value, obtain the corresponding second EGR rate after each increase in the opening degree; When the second EGR rate reaches the target EGR rate and the opening degree of the large flow passage EGR valve is less than the second set maximum opening degree, output the corresponding second target small flow passage EGR valve opening degree and the target large flow passage EGR valve opening degree; When the opening degree of the small-flow EGR valve reaches the first set maximum opening degree, the opening degree of the large-flow EGR valve reaches the second set maximum opening degree, and the corresponding EGR rate does not reach the target EGR rate, control the engine to limit the torque to meet the gas emission requirements of the engine.

2. The engine control method according to claim 1, wherein It further includes: Determine the corresponding target intake pressure based on the target performance parameters of the engine; Adjust the opening degree of the bleed valve until the intake pressure of the engine reaches the target intake pressure.

3. The engine control method according to claim 1, wherein The determining the corresponding target EGR rate based on the target performance parameters of the engine includes: Obtain the target performance parameters of the engine; Determine the target EGR rate corresponding to the target performance parameters from the corresponding relationship between the preset engine performance parameters and the EGR rate.

4. An engine control device, characterized in that, Applied to an engine controller, the engine at least includes: a first engine cylinder set, a second engine cylinder set, a first exhaust pipe, a second exhaust pipe, a first EGR branch, a second EGR branch, an EGR flow acquisition device, an asymmetric turbocharger, a bleed valve, and an engine controller; the engine has two exhaust gas recirculation EGR branches; The output end of the first engine cylinder set is connected to the first exhaust pipe. Between the first exhaust pipe and the turbine of the asymmetric turbocharger is a large-flow path of the turbine. The large-flow path of the turbine is connected to the EGR flow acquisition device through the first EGR branch. A large-flow EGR valve is provided on the first EGR branch; a first EGR cooler is provided on the first EGR branch; The output end of the second engine cylinder set is connected to the second exhaust pipe. Between the second exhaust pipe and the compressor of the asymmetric turbocharger is a small-flow path of the turbine. The small-flow path of the turbine is connected to the EGR flow acquisition device through the second EGR branch. A small-flow EGR valve is provided on the second EGR branch; a second EGR cooler is provided on the second EGR branch; The bleed valve is provided between the small-flow path of the turbine and the exhaust end of the asymmetric turbocharger; the engine control device includes: A target EGR rate determination unit for determining the corresponding target EGR rate based on the target performance parameters of the engine; An opening control unit for controlling the opening of the small-flow EGR valve; A first output unit for controlling the small-flow EGR valve to gradually increase the opening degree from the initial opening degree at a first preset amplitude. After each increase in the opening degree, control the EGR flow acquisition device to collect the EGR flow value flowing into the second EGR branch, and obtain the EGR flow value collected by the EGR flow acquisition device. Based on the EGR flow value and the engine intake flow value, obtain the corresponding first EGR rate after each increase in the opening degree; when the first EGR rate reaches the target EGR rate and the opening degree of the small-flow EGR valve is less than the first set maximum opening degree, output the corresponding first target small-flow EGR valve opening degree; A second output unit, configured to: if the opening degree of the small-channel EGR valve reaches a first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, control the opening degree of the small-channel EGR valve to maintain the first set maximum opening degree; control the large-channel EGR valve to open; control the large-channel EGR valve to gradually increase the opening degree from the initial opening degree at a second preset amplitude. After each increase in the opening degree of the large-channel EGR valve, control the EGR flow rate acquisition device to acquire the total EGR flow rate value of the first EGR branch and the second EGR branch, and based on the total EGR flow rate value and the engine intake air flow rate value, obtain the corresponding second EGR rate after each increase in the opening degree; when the second EGR rate reaches the target EGR rate and the opening degree of the large-channel EGR valve is less than the second set maximum opening degree, output the corresponding second target small-channel EGR valve opening degree and the target large-channel EGR valve opening degree; if the opening degree of the small-channel EGR valve reaches the first set maximum opening degree, the opening degree of the large-channel EGR valve reaches the second set maximum opening degree, and the corresponding EGR rate does not reach the target EGR rate, control the engine to limit the torque to meet the gas emission requirements of the engine.

5. An engine controller, characterized in that, The engine controller includes: a memory and a processor; The memory is used for storing at least one instruction; The processor is used for executing the at least one instruction to implement the engine control method according to any one of claims 1 to 3.

6. 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 3 is implemented.

7. An engine, characterized in that, 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 rate acquisition device, an asymmetric turbocharger, a wastegate valve, an intercooler, and the engine controller according to claim 5; 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. Between the first exhaust pipe and the turbine of the asymmetric turbocharger is a large turbine flow channel, and the large turbine flow channel is connected to the EGR flow rate acquisition device through the first EGR branch. A large-channel EGR valve is provided on the first EGR branch; 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. Between the second exhaust pipe and the compressor of the asymmetric turbocharger is a small turbine flow channel, and the small turbine flow channel is connected to the EGR flow rate acquisition device through the second EGR branch. A small-channel EGR valve is provided on the second EGR branch; The EGR flow rate acquisition device is connected to the intake pipe; The intercooler is arranged between the compressor and the intake pipe; The wastegate valve is arranged at the exhaust end of the small turbine flow channel and the asymmetric turbocharger; The engine controller is respectively connected to the EGR flow rate acquisition device, the large-flow EGR valve, the small-flow EGR valve, and the bleed valve, and is used to control the opening degrees of the large-flow EGR valve, the small-flow EGR valve, and the bleed valve.

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