An engine control method, device and engine system

Abstract

The application discloses an engine control method, device and system, comprising the following steps: obtaining a target rotating speed and a target torque of an engine during the operation of the engine according to a current cylinder deactivation mode vector; determining a target cylinder deactivation working condition area according to the target rotating speed and the target torque after determining a switching cylinder deactivation working condition area according to the target rotating speed and / or the target torque; judging whether the current first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix to be switched are the same; if not, obtaining a transition matrix and a cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix according to the current cylinder deactivation mode vector; and controlling the engine to operate according to the transition matrix first and then operate according to the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix after the operation of the engine according to the current cylinder deactivation mode vector is completed, so that the switching of the working condition of the engine can be ensured to be stable, the negative pressure of the cylinder can be prevented from being sucked back, and the service life of the engine can be effectively ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine control technology, and in particular to an engine control method, device and engine system. BACKGROUND

[0002] The adaptation of an engine in a power system (a vehicle, a ship or a power generation equipment) is calculated and designed according to the actual use and working condition of the power system and the maximum power demand, so as to ensure that the engine can meet the maximum power demand of the power system when all cylinders are working.

[0003] However, most of the power systems are not always in the high load working condition area in the actual working process. Thus, when these power systems work in the low load working condition area, the engine selected according to the high load output requirement has the problem of excessive displacement. The oil consumption and emission performance of these large-displacement engines is usually poor when working at low load. In order to improve their performance in the low load working condition area, the technology of changing displacement by stopping cylinders is developed. The stopping cylinder technology is a variable displacement technology of a multi-cylinder engine. It changes the actual working displacement of the engine by stopping part or all of the cylinders of the multi-cylinder engine.

[0004] The stopping cylinder technology can be roughly divided into two categories: fixed stopping cylinder and dynamic stopping cylinder. The fixed stopping cylinder stops the same one or several cylinders of the multi-cylinder engine each time. It is relatively easy to realize in control and mechanism, but it is equivalent to directly reducing the number of cylinders of the multi-cylinder engine, reduces the frequency of firing excitation of the engine, and usually causes uneven firing excitation in time, which makes the NVH (Noise, Vibration, Harshness) performance of the engine very poor. The dynamic stopping cylinder can make up for some shortcomings of the fixed stopping cylinder. In each working cycle of the engine, the cylinders stopped by the dynamic stopping cylinder can be different. Through the development of a carefully designed stopping cylinder strategy, the NVH and reliability problems caused by stopping cylinders can be reduced as much as possible while ensuring the oil / gas consumption and emission benefits of the stopping cylinder engine, but the control and mechanism implementation of the dynamic stopping cylinder is more difficult.

[0005] The dynamic skip fire (DSF) technology can realize dynamic stopping cylinder and improve the oil consumption and emission performance of the engine in the low load working condition area by making the engine work according to the corresponding firing fraction mode in each working condition area.

[0006] However, the dynamic skip fire technology has the following problems:

[0007] 1) In some DSF firing fraction modes, the firing times of each cylinder are not all equal, and the loads of each cylinder are not balanced, which is not conducive to the overall life of the engine;

[0008] 2) In some DSF firing fraction mode, some cylinders are not fired all the time. In order to ensure the in-cylinder pressure of these cylinders, recharging operation is needed after several small cycles;

[0009] 3) In some DSF firing fraction mode, the number of firing cylinders in each small cycle is not equal, which is not conducive to achieving a relatively stable working state, and is not conducive to the structural reliability and NVH of the engine;

[0010] 4) The firing fraction mode of the DSF is not optimized for specific models;

[0011] 5) The control strategy of the DSF is relatively complex, and it is difficult to realize electric control. SUMMARY

[0012] The application provides an engine control method, device and engine system, which can solve many problems existing in dynamic skip fire technology, and can realize smooth switching of engine working conditions.

[0013] According to one aspect of the application, an engine control method is provided, comprising:

[0014] During the operation of the engine according to the current cylinder deactivation mode vector, the target speed and target torque of the engine are obtained;

[0015] It is determined whether to switch the cylinder deactivation working condition area according to the target speed and / or the target torque;

[0016] If yes, the target cylinder deactivation working condition area is determined according to the target speed and target torque;

[0017] The cylinder deactivation mode matrix in which the current cylinder deactivation mode vector is located is obtained and determined as a first cylinder deactivation mode matrix, and the cylinder deactivation mode matrix corresponding to the target working condition area is obtained and determined as a second cylinder deactivation mode matrix;

[0018] It is determined whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same;

[0019] If not, a transition matrix and a cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix are obtained according to the current cylinder deactivation mode vector;

[0020] After the operation of the engine according to the current cylinder deactivation mode vector is completed, the engine is first controlled to operate according to the transition matrix, and then controlled to operate according to the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix;

[0021] The step of obtaining the target speed and the target torque of the engine is performed in a process in which the engine is running according to the current deactivation mode vector.

[0022] Optionally, if it is determined that the first deactivation mode matrix is the same as the second deactivation mode matrix, a deactivation mode vector for initial running after switching to the second deactivation mode matrix is directly obtained.

[0023] After the engine runs according to the current deactivation mode vector, the engine is controlled to run according to the deactivation mode vector for initial running after switching to the second deactivation mode matrix.

[0024] The step of obtaining the target speed and the target torque of the engine is performed in a process in which the engine is running according to the current deactivation mode vector.

[0025] Optionally, the engine control method further comprises: if it is determined that the deactivation working condition area is not switched according to the speed and / or the torque, the actual number of cycles in which the engine runs according to the current deactivation mode vector is obtained.

[0026] It is determined whether the actual number of cycles is equal to a preset number of cycles corresponding to the current deactivation mode vector.

[0027] If yes, a next deactivation mode vector located after the current deactivation mode vector in the current deactivation mode matrix is obtained.

[0028] After the engine runs according to the current deactivation mode vector, the engine is controlled to run according to the next deactivation mode vector.

[0029] The step of obtaining the target speed and the target torque of the engine is performed in a process in which the engine is running according to the current deactivation mode vector.

[0030] Optionally, after it is determined that the first deactivation mode matrix is different from the second deactivation mode matrix, and before the transition matrix and the deactivation mode vector for initial running after switching to the second deactivation mode matrix are obtained according to the current deactivation mode vector, the method further comprises:

[0031] It is determined whether the state of each cylinder in each deactivation mode vector in the second deactivation mode matrix is a firing state.

[0032] If no, the step of obtaining the transition matrix and the deactivation mode vector for initial running after switching to the second deactivation mode matrix according to the current deactivation mode vector is performed.

[0033] Optionally, if it is determined that the state of each cylinder in each cylinder deactivation mode vector in the second cylinder deactivation mode matrix is a firing state, after the engine runs according to the current cylinder deactivation mode vector, the engine is controlled to run according to any cylinder deactivation mode vector in the second cylinder deactivation mode matrix.

[0034] Optionally, the transition matrix includes a cylinder deactivation mode vector.

[0035] After the engine runs according to the current cylinder deactivation mode vector, the engine is controlled to first run according to the transition matrix, and then run according to the cylinder deactivation mode vector initially run after switching to the second cylinder deactivation mode matrix, including:

[0036] After the engine runs according to the current cylinder deactivation mode vector, the engine is controlled to run according to the transition matrix.

[0037] After the engine runs according to the transition matrix for one cycle, the engine is controlled to run according to the cylinder deactivation mode vector initially run after switching to the second cylinder deactivation mode matrix.

[0038] Optionally, during the process in which the engine runs according to the current sub-cycle, before the engine speed and torque are obtained, the method further includes:

[0039] After the engine is started, cylinder deactivation working condition areas of the engine under different numbers of cylinders are obtained; each cylinder deactivation working condition area includes a one-to-one corresponding cylinder deactivation mode matrix.

[0040] An initial target engine speed and an initial target engine torque are obtained.

[0041] According to the initial target engine speed and / or the initial target engine torque, a corresponding initial target cylinder deactivation working condition area is determined.

[0042] An initial target cylinder deactivation mode matrix corresponding to the initial target cylinder deactivation working condition area is obtained.

[0043] An initial target cylinder deactivation mode vector initially run after switching to the initial target cylinder deactivation mode matrix is obtained.

[0044] The engine is controlled to run according to the initial target cylinder deactivation mode vector initially run after switching to the initial target cylinder deactivation mode matrix.

[0045] Optionally, obtaining the cylinder deactivation working condition areas of the engine under different numbers of cylinders includes:

[0046] An advantage working condition area corresponding to each number of cylinders is obtained.

[0047] The advantage working condition areas are equally spaced in the rotation speed dimension to obtain each of the cylinder deactivation working condition areas included in the advantage working condition areas.

[0048] According to another aspect of the present application, an engine control device is provided, comprising:

[0049] a rotation speed-torque obtaining module, configured to obtain a target rotation speed and a target torque of the engine during operation of the engine according to a current cylinder deactivation mode vector;

[0050] a first judging module, configured to judge whether to switch a cylinder deactivation working condition area according to the target rotation speed and / or the target torque;

[0051] a target cylinder deactivation working condition area determining module, configured to determine a target cylinder deactivation working condition area according to the target rotation speed and the target torque after the first judging module determines to switch a cylinder deactivation working condition area according to the target rotation speed and / or the target torque;

[0052] a matrix determining module, configured to obtain a cylinder deactivation mode matrix in which the current cylinder deactivation mode vector is located and determine the cylinder deactivation mode matrix as a first cylinder deactivation mode matrix, and obtain a cylinder deactivation mode matrix corresponding to the target working condition area and determine the cylinder deactivation mode matrix as a second cylinder deactivation mode matrix;

[0053] a second judging module, configured to judge whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same;

[0054] a first switching information obtaining module, configured to obtain a transition matrix and a cylinder deactivation mode vector initially operated after switching to the second cylinder deactivation mode matrix according to the current cylinder deactivation mode vector when the second judging module determines that the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are not the same;

[0055] a first control module, configured to control the engine to first operate according to the transition matrix and then operate according to the cylinder deactivation mode vector initially operated after switching to the second cylinder deactivation mode matrix after the engine operation according to the current cylinder deactivation mode vector is completed;

[0056] a first cycle module, configured to return to execute the step of obtaining the target rotation speed and the target torque of the engine during operation of the engine according to the current cylinder deactivation mode vector after the first control module controls the engine to first operate according to the transition matrix and then operate according to the cylinder deactivation mode vector initially operated after switching to the second cylinder deactivation mode matrix.

[0057] According to another aspect of the present application, an engine system is provided, comprising a controller and a plurality of cylinders;

[0058] The controller is configured to execute the above-mentioned engine control method.

[0059] The engine control method provided by the embodiment of the present application can determine whether to switch the deactivation working condition area when the target speed and / or the target torque changes, and can determine the target deactivation working condition area according to the target speed and the target torque when the deactivation working condition area needs to be switched. The deactivation mode matrix in which the current deactivation mode vector is located is determined as a first deactivation mode matrix, and the deactivation mode matrix corresponding to the target working condition area is determined as a second deactivation mode matrix. The first deactivation mode matrix and the second deactivation mode matrix are compared, and when the first deactivation mode matrix and the second deactivation mode matrix are different, the transition matrix and the deactivation mode vector for initial operation after switching to the second deactivation mode matrix are obtained according to the current deactivation mode vector. Therefore, after the engine runs according to the current deactivation mode vector, the engine is first controlled to run according to the transition matrix, and then is controlled to run according to the deactivation mode vector for initial operation after switching to the second deactivation mode matrix. When the first deactivation mode matrix and the second deactivation mode matrix are different, the engine can be smoothly switched between working conditions under the connection of the transition matrix, without large amplitude jitter. In addition, when the current deactivation mode vector and the deactivation mode vector for initial operation after switching to the second deactivation mode matrix are both in the state of deactivation of the same cylinder, the connection of the transition matrix can avoid the situation that the cylinder deactivation time is too long to cause oil backflow due to negative pressure in the cylinder, and can effectively ensure the service life of the engine.

[0060] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0062] Figure 1 is a flowchart of an engine control method provided by the embodiment of the present application;

[0063] Figure 2 is a schematic diagram of a deactivation mode vector provided by the embodiment of the present application;

[0064] Figure 3 is a schematic diagram of a deactivation mode matrix of the deactivation working condition area "3".

[0065] Figure 4 is a schematic diagram of the deactivation mode matrix of the deactivation operating region "6"

[0066] Figure 5 is a schematic diagram of the deactivation mode matrix of the deactivation operating region "7";

[0067] Figure 6 is a schematic diagram of an engine operating region according to an embodiment of the application

[0068] Figure 7 is a flow chart of another engine control method according to an embodiment of the application

[0069] Figure 8 is a flow chart of another engine control method according to an embodiment of the application

[0070] Figure 9 is a schematic diagram of an engine operating region according to an embodiment of the application

[0071] Figure 10 is a schematic diagram of an engine control device according to an embodiment of the application DETAILED DESCRIPTION

[0072] In order to enable persons skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative work should fall within the scope of protection of the present application.

[0073] It should be noted that the terms "first", "second", and the like in the description and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to include only those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to the process, method, product or device.

[0074] The engine control method provided by the embodiment of the present application can ensure the NVH, reliability and timeliness of power response of the engine in the cylinder deactivation mode, and the engine control method can be executed by the engine control device provided by the embodiment of the present application, the engine control device can be realized in the form of software and / or hardware, and the engine control device can be configured in the controller of the engine control system.

[0075] Figure 1 A flowchart of the engine control method provided by the embodiment of the present application is shown in Figure 1 , and the method comprises the following steps.

[0076] In S110, the target speed and the target torque of the engine are obtained during the operation of the engine according to the current cylinder deactivation mode vector.

[0077] Specifically, for a four-stroke piston reciprocating engine, the crankshaft completes one working cycle for every 720 degrees of rotation, so the working period corresponding to the 720 degrees of rotation of the crankshaft is referred to as one cycle. In one cycle, the state combination of each cylinder in the engine is the cylinder deactivation mode vector of the engine in this cycle. Figure 2 is a schematic diagram of a cylinder deactivation mode vector provided by the embodiment of the present application, as shown in Figure 2 , the length of the cylinder deactivation mode vector is equal to the number of cylinders of the engine, each element in the vector corresponds to a cylinder, and the value of the element represents the state of the cylinder, for example, the value of the element is "1" which means the state of the cylinder is normal ignition, the value of the element is "0" which means the state of the cylinder is cylinder deactivation, and the cylinder number is the digital identifier of each cylinder. When the engine starts to operate, the cylinder deactivation mode vector to be operated by the engine can be obtained first, and the states of each cylinder in the engine are controlled according to the cylinder deactivation mode vector, so as to reduce the displacement of the engine and at the same time make the power output of the engine meet the demand. During the operation of the engine according to the current cylinder deactivation mode vector, the target speed and the target torque of the engine can be obtained in real time, and the target speed and the target torque are the required demand speed and the required demand torque of the engine.

[0078] In S120, it is judged whether to switch the cylinder deactivation working condition area according to the target speed and / or the target torque, and if yes, S130 is executed.

[0079] Specifically, according to the different speeds and different torques, the engine can include multiple cylinder deactivation working condition areas, and different cylinder deactivation working condition areas correspond to different cylinder deactivation mode matrices. In each cylinder deactivation mode matrix, each row of the matrix corresponds to one cycle of the engine, that is, one cylinder deactivation mode vector, each column of the matrix corresponds to one cylinder of the engine, and the value of each element in the matrix can be 1 or 0, which respectively represents whether the corresponding cylinder normally ignites in the corresponding cycle, that is, it can be understood that the cylinder deactivation mode matrix is composed of cylinder deactivation mode vectors arranged by rows.Figures 3-5 Fig. 1 shows a schematic diagram of a cylinder deactivation mode matrix of several cylinder deactivation operating zones, wherein, Figure 3 Fig. 2 shows a schematic diagram of a cylinder deactivation mode matrix of a cylinder deactivation operating zone "3", Figure 4 Fig. 3 shows a schematic diagram of a cylinder deactivation mode matrix of a cylinder deactivation operating zone "6", Figure 5 Fig. 4 shows a schematic diagram of a cylinder deactivation mode matrix of a cylinder deactivation operating zone "7", wherein, the cycle number represents the row order number of each cycle in the cylinder deactivation mode matrix, and the cylinder number represents the number of each cylinder in the engine, which can correspond to the corresponding cylinder. For example, Figure 3 For example, the cylinder deactivation operating zone "3" is one of the cylinder deactivation operating zones in the first dominant operating zone A1, and the cylinder deactivation mode matrix of the cylinder deactivation operating zone includes 30 cycles arranged in rows, wherein the cylinder deactivation mode vectors of the first row to the fifteenth row are the same and are (1, 1, 1, 0, 0, 0). The cylinder deactivation mode vectors of the sixteenth row to the thirtieth row are the same and are (0, 0, 0, 1, 1, 1), that is, when the engine is operated according to the first row cylinder mode vector, a maximum of 15 cycles can be operated, and when the engine is operated according to the second row cylinder mode vector, a maximum of 15 cycles can be operated.

[0080] Since the engine can include multiple cylinder deactivation operating zones according to different speeds and different torques, Figure 6 Fig. 5 shows a schematic diagram of an operating condition of an engine according to an embodiment of the present application, as Figure 6 As shown in Fig. 5, when the target speed and / or the target torque of the engine change, the cylinder deactivation operating zone can correspondingly change, so that the target speed can be detected in real time whether it is still within the speed range corresponding to the current cylinder deactivation operating zone, or the target torque can be detected in real time whether it is still within the torque range corresponding to the current cylinder deactivation operating zone, or both the target speed and the target torque can be detected in real time whether they are still within the speed range and the torque range corresponding to the current cylinder deactivation operating zone. When the target speed is not within the speed range corresponding to the current cylinder deactivation operating zone, and / or the target torque is not within the torque range corresponding to the current cylinder deactivation operating zone, it is determined to switch the cylinder deactivation operating zone.

[0081] S130, determining a target cylinder deactivation operating zone according to the target speed and / or the target torque.

[0082] Specifically, after it is determined that the cylinder deactivation operating zone needs to be switched, the target cylinder deactivation operating zone to be switched can be determined according to the current target speed and the target torque based on the look-up table method, that is, in combination with reference Figure 6 to Fig. 5, the region where the coordinate point of the current target speed and the target torque is located is determined, and the cylinder deactivation operating zone where the coordinate point is located is the target cylinder deactivation operating zone.

[0083] S140, obtain the current cylinder deactivation mode matrix in which the cylinder deactivation mode vector is located and determine it as a first cylinder deactivation mode matrix, and obtain the cylinder deactivation mode matrix corresponding to the target working condition area and determine it as a second cylinder deactivation mode matrix.

[0084] S150, judge whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same; if not, execute step S160.

[0085] Specifically, for the cylinder deactivation working condition area with the same number of cylinders, the corresponding cylinder deactivation mode matrix may be the same or different, so the current cylinder deactivation mode matrix and the cylinder deactivation mode matrix of the target working condition area can be compared to determine whether they are the same. At this time, the cylinder deactivation mode matrix in which the current cylinder deactivation mode vector is located can be first determined as the first cylinder deactivation mode matrix, and the cylinder deactivation mode matrix corresponding to the target working condition area can be determined as the second cylinder deactivation mode matrix, and whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same can be judged.

[0086] For example, each cylinder deactivation mode matrix can have a one-to-one matrix number, and whether the matrix number of the first cylinder deactivation mode matrix and the matrix number of the second cylinder deactivation mode matrix are the same can be directly judged. If the matrix number of the first cylinder deactivation mode matrix and the matrix number of the second cylinder deactivation mode matrix are the same, it can be determined that the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same; and if the matrix number of the first cylinder deactivation mode matrix and the matrix number of the second cylinder deactivation mode matrix are different, it can be determined that the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are different. In this way, the process can be simplified.

[0087] S160, obtain the transition matrix and the cylinder deactivation mode vector initially running after switching to the second cylinder deactivation mode matrix according to the current cylinder deactivation mode vector.

[0088] Specifically, if it is determined that the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are different, the transition matrix and the cylinder deactivation mode vector initially running after switching to the second cylinder deactivation mode matrix can be obtained according to the current cylinder deactivation mode vector based on a dynamics algorithm. The possible forms of the transition matrix and the cylinder deactivation mode vectors in the second cylinder deactivation mode matrix can be sequentially calculated with the current cylinder deactivation mode vector in a traversal manner, and the transition matrix and the cylinder deactivation mode matrix that make the engine performance optimal are determined as the final transition matrix and the cylinder deactivation mode vector initially running after switching to the second cylinder deactivation mode matrix, respectively.

[0089] Exemplarily, the transition matrix can only include one row vector, i.e., one deactivation mode vector. After the engine runs according to the current deactivation mode vector, the engine is controlled to run according to the transition matrix first, and then run according to the deactivation mode vector initially running after switching to the second deactivation mode matrix. After the engine runs according to the current deactivation mode vector, the engine is controlled to run according to the transition matrix; and after the engine runs according to the transition matrix for one cycle, the engine is controlled to run according to the deactivation mode vector initially running after switching to the second deactivation mode matrix. In this way, the response speed of the engine can be improved, so as to quickly meet the power demand of the engine.

[0090] S170、After the engine runs according to the current deactivation mode vector, the engine is controlled to run according to the transition matrix first, and then run according to the deactivation mode vector initially running after switching to the second deactivation mode matrix. Return to step S110.

[0091] Specifically, when the engine is controlled to switch the deactivation mode matrix, the engine is controlled to run according to the transition matrix first after the engine runs according to the current deactivation mode vector, and then run according to the deactivation mode vector initially running after switching to the second deactivation mode matrix after the transition matrix runs. Thus, in subsequent operation, each row deactivation mode vector in the deactivation mode matrix corresponding to the target deactivation working condition area can be run. In this way, when the first deactivation mode matrix and the second deactivation mode matrix are different, the engine can be smoothly switched under the connection of the transition matrix, and the case of large amplitude jitter can be avoided. Moreover, for the current deactivation mode vector and the deactivation mode vector initially running after switching to the second deactivation mode matrix, when the state of the same cylinder in the two deactivation mode vectors is deactivation, the connection through the transition matrix can avoid the case that the deactivation time of the cylinder is too long to cause oil backflow due to negative pressure in the cylinder, and can effectively ensure the service life of the engine.

[0092] It can be understood that the engine is controlled to run according to the deactivation mode vector, i.e., each cylinder in the engine is controlled to run according to the corresponding state in the deactivation mode vector.

[0093] The engine control method provided by the embodiment of the present application can obtain the target rotating speed and the target torque of the engine during the operation of the engine according to the current stop-cylinder mode vector, so that whether to switch the stop-cylinder working condition area can be determined in time when the target rotating speed and / or the target torque changes. When it is necessary to switch the stop-cylinder working condition area, the target stop-cylinder working condition area can be determined according to the target rotating speed and the target torque, the stop-cylinder mode matrix in which the current stop-cylinder mode vector is located is obtained and determined as the first stop-cylinder mode matrix, and the stop-cylinder mode matrix corresponding to the target working condition area is obtained and determined as the second stop-cylinder mode matrix, so as to compare the first stop-cylinder mode matrix currently operated with the second stop-cylinder mode matrix to be switched. When it is determined that the first stop-cylinder mode matrix is different from the second stop-cylinder mode matrix, the transition matrix and the stop-cylinder mode vector initially operated after switching to the second stop-cylinder mode matrix can be obtained according to the current stop-cylinder mode vector, so that after the operation of the engine according to the current stop-cylinder mode vector is completed, the engine is controlled to first operate according to the transition matrix and then operate according to the stop-cylinder mode vector initially operated after switching to the second stop-cylinder mode matrix. When the first stop-cylinder mode matrix is different from the second stop-cylinder mode matrix, the engine can be smoothly switched between working conditions under the connection of the transition matrix, without large amplitude of shaking. In addition, when the current stop-cylinder mode vector and the stop-cylinder mode vector initially operated after switching to the second stop-cylinder mode matrix are both in the state of stopping the same cylinder, the connection through the transition matrix can avoid the situation that the stop-cylinder time of the cylinder is too long to cause the negative pressure in the cylinder and the oil backflow, so that the service life of the engine can be effectively ensured.

[0094] Optionally, Figure 7 is a flowchart of another engine control method provided by the embodiment of the present application, as shown in the figure, the engine control method comprises the following steps. Figure 7

[0095] S211, obtaining the target rotating speed and the target torque of the engine during the operation of the engine according to the current stop-cylinder mode vector.

[0096] S212, determining whether to switch the stop-cylinder working condition area according to the target rotating speed and / or the target torque; if yes, performing step S217; if no, performing step S213.

[0097] S213, obtaining the actual cycle number of the engine operated according to the current stop-cylinder mode vector.

[0098] Specifically, during the operation of the engine, a counter can be used to record the actual cycle number of the engine operated according to the current stop-cylinder mode vector, and the counter is reset to zero when the stop-cylinder mode vector is switched, so that the actual cycle number of each stop-cylinder mode vector can be counted, and thus the actual cycle number of the current stop-cylinder mode vector can be directly obtained when necessary. ​

[0099] S214, determine whether the actual number of cycles is equal to the preset number of cycles corresponding to the current cylinder deactivation mode vector; if yes, execute step S215; if no, return to execute step S211.

[0100] Specifically, in each cylinder deactivation mode matrix, each row of cylinder deactivation mode vectors can be respectively set with a preset number of cycles, which can be calibrated through experiments based on the criterion of avoiding the situation of oil sucking due to excessively low in-cylinder pressure. After obtaining the actual number of cycles of the current cylinder deactivation mode vector, the preset number of cycles corresponding to the current cylinder deactivation mode vector can be compared with the actual number of cycles. If the actual number of cycles is equal to the preset number of cycles, it indicates that the engine has run for a limited time according to the current cylinder deactivation mode vector. If the engine continues to run according to the current cylinder deactivation mode vector in the next cycle, the cylinders in the cylinder deactivation state will have the situation of oil sucking due to excessively low in-cylinder pressure. If the actual number of cycles is less than the preset number of cycles, it indicates that the cylinders in the cylinder deactivation state will not have the situation of oil sucking due to excessively low in-cylinder pressure, and the engine can be controlled to continue to run according to the current cylinder deactivation mode vector in the next cycle.

[0101] S215, obtain the next cylinder deactivation mode vector located after the current cylinder deactivation mode vector in the current cylinder deactivation mode matrix.

[0102] S216, after the engine finishes running according to the current cylinder deactivation mode vector, control the engine to run according to the next cylinder deactivation mode vector; return to execute step S211.

[0103] Specifically, after determining that the actual number of continuous running times is equal to the preset number of continuous running times corresponding to the current cylinder deactivation mode vector, the next cylinder deactivation mode vector located after the current cylinder deactivation mode vector in the current cylinder deactivation mode matrix can be obtained. After the engine finishes running according to the current cylinder deactivation mode vector, the engine is controlled to run according to the obtained next cylinder deactivation mode vector. In this way, the cylinders can be effectively prevented from being in the cylinder deactivation state for a long time, thereby avoiding the situation of oil sucking due to excessively low in-cylinder pressure.

[0104] S217, determine a target cylinder deactivation working condition area according to the target speed and the target torque.

[0105] S218, obtain the cylinder deactivation mode matrix in which the current cylinder deactivation mode vector is located and determine it as a first cylinder deactivation mode matrix, and obtain the cylinder deactivation mode matrix corresponding to the target working condition area and determine it as a second cylinder deactivation mode matrix.

[0106] S219, determine whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same; if yes, execute step S222; if no, execute step S220.

[0107] S220, obtaining a transition matrix and a cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix according to the current cylinder deactivation mode vector.

[0108] S221, after the engine completes operation according to the current cylinder deactivation mode vector, controlling the engine to first operate according to the transition matrix, and then operate according to the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix; returning to step S211.

[0109] S222, directly obtaining the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix.

[0110] S223, after the engine completes operation according to the current cylinder deactivation mode vector, controlling the engine to operate according to the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix; returning to step S211.

[0111] Specifically, if it is determined that the currently operating cylinder deactivation mode matrix (i.e., the first cylinder deactivation mode matrix) is the same as the target cylinder deactivation mode matrix to be switched (i.e., the second cylinder deactivation mode matrix), the transition matrix can not be obtained, and the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix can be directly obtained. After the engine completes operation according to the current cylinder deactivation mode vector, the engine can be directly switched to the second cylinder deactivation mode matrix and operated according to the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix. This can improve the response speed of the engine when switching between cylinder deactivation operating regions and quickly meet the power demand of the engine. The cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix can be determined based on a dynamic algorithm according to the current cylinder deactivation mode vector. Alternatively, since the first cylinder deactivation mode matrix is the same as the second cylinder deactivation mode matrix, the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix can be mapped to each other. The cylinder deactivation mode vector located in the next row of the current cylinder deactivation mode vector can be mapped to the second cylinder deactivation mode matrix. The cylinder deactivation mode vector located in the same position is the cylinder deactivation mode vector for initial operation after switching to the second cylinder deactivation mode matrix. This can simplify the calculation process when switching between cylinder deactivation mode matrices.

[0112] Optionally, Figure 8 is a flowchart of another engine control method provided by an embodiment of the present application, as shown in Figure 8 The engine control method comprises the following steps:

[0113] S311, after the engine is started, obtaining cylinder deactivation operating regions of the engine under different cylinder deactivation quantities.

[0114] Each cylinder deactivation operating region comprises a one-to-one corresponding cylinder deactivation mode matrix.

[0115] Exemplarily, the advantageous working condition zones corresponding to respective numbers of cylinder deactivation are first acquired, each advantageous working condition zone is equally spaced in the dimension of rotation speed, and each cylinder deactivation working condition zone included in the advantageous working condition zone is acquired.

[0116] Specifically, different numbers of cylinder deactivation correspond to different advantageous working condition zones. The advantageous working condition zone refers to a rotation speed-torque region corresponding to an optimal working state of the engine under different numbers of cylinder deactivation. For the same number of cylinder deactivation, different advantageous working condition zones corresponding to different rotation speeds and different torques can include multiple cylinder deactivation working condition zones. Figure 9 is another working condition diagram of an engine provided by an embodiment of the present application, Figure 9 shown is a diagrammatic representation of the rotation speed-torque region of the engine under different numbers of cylinder deactivation corresponding to an optimal working state calculated through a simulation experiment, taking a six-cylinder engine as an example. Exemplarily, four advantageous working condition zones are shown in the diagram, namely, a first advantageous working condition zone A1 of the number of cylinder deactivation being 3 (i.e., 3 cylinders firing), a second advantageous working condition zone A2 of the number of cylinder deactivation being 2 (i.e., 4 cylinders firing), a third advantageous working condition zone A3 of the number of cylinder deactivation being 1 (i.e., 5 cylinders firing), and a fourth advantageous working condition zone A4 of the number of cylinder deactivation being 0 (i.e., 6 cylinders firing). Figure 3 is a diagrammatic representation of a cylinder deactivation working condition zone provided by an embodiment of the present application. On the basis of the advantageous working condition zone being determined, the advantageous working condition zone can be divided in the dimension of rotation speed or torque, and the cylinder deactivation working condition zone in each advantageous working condition zone is determined. Figure 6 is a case of dividing the advantageous working condition zone in the dimension of rotation speed, and as Figure 6 shown, in the rotation speed interval of 700 rpm-1700 rpm, the first advantageous working condition zone A1, the second advantageous working condition zone A2, and the third advantageous working condition zone A3 are divided into 24 cylinder deactivation working condition zones at equal intervals of 100 rpm, and each cylinder deactivation working condition zone is numbered. In other feasible embodiments, the lengths of the rotation speed intervals corresponding to the cylinder deactivation working condition zones can also be different.

[0117] S312, acquiring an initial target rotation speed and an initial target torque of the engine.

[0118] S313, determining a corresponding initial target cylinder deactivation working condition zone according to the initial target rotation speed and / or the initial target torque of the engine.

[0119] S314, acquiring an initial target cylinder deactivation mode matrix corresponding to the initial target cylinder deactivation working condition zone.

[0120] S315, acquiring a cylinder deactivation mode vector of initial operation after cutting into the initial target cylinder deactivation mode matrix.

[0121] S316, controlling the engine to operate according to the cylinder deactivation mode vector of initial operation after cutting into the initial target cylinder deactivation mode matrix.

[0122] Specifically, the way of determining the initial target deactivation mode region according to the initial target speed and / or the initial target torque is the same as the way of determining the target deactivation mode region according to the target speed and / or the target torque introduced in the above embodiments, which will not be repeated here. When the deactivation mode vector for initial running after cutting into the initial target deactivation mode matrix is obtained, the deactivation mode vector for initial running after cutting into the initial target deactivation mode matrix can be determined according to the current target speed and target torque based on the dynamics algorithm, or the engine can be directly controlled to run according to the first row deactivation mode vector in the initial target deactivation mode matrix.

[0123] S317, obtaining the target speed and target torque of the engine during the running of the engine according to the current deactivation mode vector.

[0124] S318, determining whether to switch the deactivation mode region according to the target speed and / or the target torque; if yes, executing step S319; if no, executing step S319.

[0125] S319, obtaining the actual cycle number of the engine running according to the current deactivation mode vector.

[0126] S320, determining whether the actual cycle number is equal to the preset cycle number corresponding to the current deactivation mode vector; if yes, executing step S321; if no, returning to execute step S317.

[0127] S321, obtaining the next deactivation mode vector located after the current deactivation mode vector in the current deactivation mode matrix.

[0128] S322, after the running of the engine according to the current deactivation mode vector is completed, controlling the engine to run according to the next deactivation mode vector; returning to execute step S317.

[0129] S323, determining the target deactivation mode region according to the target speed and target torque.

[0130] S324, obtaining the deactivation mode matrix in which the current deactivation mode vector is located and determining it as the first deactivation mode matrix, and obtaining the deactivation mode matrix corresponding to the target deactivation mode region and determining it as the second deactivation mode matrix.

[0131] S325, determining whether the first deactivation mode matrix and the second deactivation mode matrix are the same; if yes, executing step S330; if no, executing step S326.

[0132] S326, determining whether the state of each cylinder in each deactivation mode vector in the second deactivation mode matrix is the firing state; if yes, executing step S327, if no, executing step S328.

[0133] S327. After the engine has finished running according to the current cylinder deactivation mode vector, control the engine to run according to any cylinder deactivation mode vector in the second cylinder deactivation mode matrix.

[0134] Specifically, if in the second cylinder deactivation mode matrix, the state of each cylinder in each cylinder deactivation mode vector is the firing state, then it means that the cylinder deactivation operating condition region corresponding to the second cylinder deactivation mode matrix is ​​the operating condition region where all cylinders are firing, that is, the cylinder deactivation operating condition region belongs to 9 or 1 in the figure. Figure 6 The fourth advantageous operating condition zone A4. Since the state of each cylinder in each cylinder deactivation mode vector is the firing state, the cylinder in the cylinder deactivation state in the current cylinder deactivation mode vector will definitely switch to the firing state. There will be no situation where the cylinder deactivates again and there is a possibility of negative pressure backflow. Therefore, at this time, after the engine has finished running according to the current cylinder deactivation mode vector, the engine can be controlled to run directly according to any cylinder deactivation mode vector in the second cylinder deactivation mode matrix.

[0135] S328. Obtain the transition matrix and the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix based on the current cylinder deactivation mode vector.

[0136] S329. After the engine has completed its operation according to the current cylinder deactivation mode vector, control the engine to first operate according to the transition matrix, and then operate according to the cylinder deactivation mode vector that was initially operated after switching to the second cylinder deactivation mode matrix; return to step S311.

[0137] S330, directly obtain the cylinder deactivation mode vector of the initial operation after switching to the second cylinder deactivation mode matrix.

[0138] S331. After the engine completes the current cylinder deactivation mode vector, control the engine to run according to the cylinder deactivation mode vector that was initially run after switching to the second cylinder deactivation mode matrix; return to step S311.

[0139] Based on the same inventive concept, embodiments of the present invention also provide an engine control device. This engine control device is used to execute the engine control method provided in any embodiment of the present invention. The engine control device can be implemented by software and / or hardware. Therefore, the engine control device provided in the embodiments of the present invention includes the technical features of the engine control method provided in any embodiment of the present invention, and can achieve the beneficial effects of the engine control method provided in any embodiment of the present invention. The similarities can be referred to the above description of the engine control method provided in the embodiments of the present invention, and will not be repeated here.

[0140] Figure 10 This is a schematic diagram of the structure of an engine control device provided in an embodiment of the present invention, as shown below. Figure 10As shown, the engine control device comprises a speed-torque acquisition module 100, configured to acquire a target speed and a target torque of the engine during operation of the engine according to a current deactivation mode vector; a first judgment module 200, configured to judge whether to switch a deactivation working condition area according to the target speed and / or the target torque; a target deactivation working condition area determination module 300, configured to determine a target deactivation working condition area according to the target speed and the target torque after the first judgment module 200 determines to switch the deactivation working condition area according to the target speed and / or the target torque; a matrix determination module 400, configured to acquire a deactivation mode matrix in which the current deactivation mode vector is located and determine the deactivation mode matrix as a first deactivation mode matrix, and acquire a deactivation mode matrix corresponding to the target working condition area and determine the deactivation mode matrix as a second deactivation mode matrix; a second judgment module 500, configured to judge whether the first deactivation mode matrix and the second deactivation mode matrix are the same; a first switching information acquisition module 600, configured to acquire a transition matrix and a deactivation mode vector initially operated after switching to the second deactivation mode matrix according to the current deactivation mode vector when the second judgment module 500 determines that the first deactivation mode matrix and the second deactivation mode matrix are not the same; a first control module 700, configured to control the engine to first operate according to the transition matrix and then operate according to the deactivation mode vector initially operated after switching to the second deactivation mode matrix after the operation of the engine according to the current deactivation mode vector is completed; and a first cycle module 800, configured to return to execute the step of acquiring the target speed and the target torque of the engine during the operation of the engine according to the current deactivation mode vector after the first control module 700 controls the engine to first operate according to the transition matrix and then operate according to the deactivation mode vector initially operated after switching to the second deactivation mode matrix.

[0141] The engine control device provided by the embodiment of the application can ensure smooth switching of working conditions of the engine under the transition of the transition matrix when the first deactivation mode matrix and the second deactivation mode matrix are different, and the situation that the state of the same cylinder in the current deactivation mode vector and the deactivation mode vector initially operated after switching to the second deactivation mode matrix is deactivation, and can avoid the situation that the deactivation time of the cylinder is too long to cause oil backflow caused by negative pressure in the cylinder, and can effectively ensure the service life of the engine.

[0142] Based on the same inventive concept, the embodiment of the application further provides an engine system comprising a controller and a plurality of cylinders, wherein the controller is configured to execute the engine control method provided by any of the embodiments of the application, and thus the engine system provided by the embodiment of the application comprises the technical features of the engine control method provided by any of the embodiments of the application, and can achieve the beneficial effects of the engine control method provided by any of the embodiments of the application, and the same parts can be referred to the description of the engine control method provided by the embodiment of the application, which will not be described herein again.

[0143] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps described in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which are not limited herein.

[0144] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An engine control method, characterized in that, include: During the operation of the engine according to the current cylinder deactivation mode vector, the target speed and target torque of the engine are obtained; Determine whether to switch to the cylinder deactivation mode based on the target speed and / or the target torque; If so, then the target cylinder deactivation zone is determined based on the target speed and target torque; Obtain the cylinder deactivation mode matrix where the current cylinder deactivation mode vector is located and determine it as the first cylinder deactivation mode matrix; and obtain the cylinder deactivation mode matrix corresponding to the target cylinder deactivation condition zone and determine it as the second cylinder deactivation mode matrix. Determine whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same; If not, then obtain the transition matrix and the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix based on the current cylinder deactivation mode vector; After the engine has completed its operation according to the current cylinder deactivation mode vector, the engine is controlled to first operate according to the transition matrix, and then operate according to the cylinder deactivation mode vector initially operated after switching to the second cylinder deactivation mode matrix. Return to the step of obtaining the target speed and target torque of the engine during the process of the engine operating according to the current cylinder deactivation mode vector.

2. The engine control method according to claim 1, characterized in that, If it is determined that the first cylinder deactivation mode matrix is ​​the same as the second cylinder deactivation mode matrix, then the cylinder deactivation mode vector of the initial operation after switching to the second cylinder deactivation mode matrix is ​​directly obtained; After the engine has finished running according to the current cylinder deactivation mode vector, control the engine to run according to the cylinder deactivation mode vector that was initially run after switching to the second cylinder deactivation mode matrix; Return to the step of obtaining the target speed and target torque of the engine during the process of the engine operating according to the current cylinder deactivation mode vector.

3. The engine control method according to claim 1, characterized in that, Also includes: If it is determined that the cylinder deactivation mode will not be switched based on the target speed and / or the target torque, then the actual number of cycles the engine runs according to the current cylinder deactivation mode vector is obtained; Determine whether the actual number of cycles is equal to the preset number of cycles corresponding to the current cylinder deactivation mode vector; If so, then obtain the next cylinder deactivation mode vector in the current cylinder deactivation mode matrix that is located after the current cylinder deactivation mode vector; After the engine has finished operating according to the current cylinder deactivation mode vector, control the engine to operate according to the next cylinder deactivation mode vector; Return to the step of obtaining the target speed and target torque of the engine during the process of the engine operating according to the current cylinder deactivation mode vector.

4. The engine control method according to claim 1, characterized in that, After determining that the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are different, and before obtaining the transition matrix and the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix based on the current cylinder deactivation mode vector, the method further includes: Determine whether the state of each cylinder in each cylinder stop mode vector in the second cylinder stop mode matrix is ​​the firing state; If not, then proceed with the steps of obtaining the transition matrix and the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix based on the current cylinder deactivation mode vector.

5. The engine control method according to claim 4, characterized in that, If it is determined that in the second cylinder deactivation mode matrix, the state of each cylinder in each cylinder deactivation mode vector is the firing state, then after the engine has finished running according to the current cylinder deactivation mode vector, the engine is controlled to run according to any cylinder deactivation mode vector in the second cylinder deactivation mode matrix.

6. The engine control method according to claim 1, characterized in that, The transition matrix includes a cylinder deactivation mode vector; After the engine completes operation according to the current cylinder deactivation mode vector, the engine is controlled to first operate according to the transition matrix, and then operate according to the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix, including: After the engine has completed operating according to the current cylinder deactivation mode vector, control the engine to operate according to the transition matrix; After controlling the engine to run one cycle according to the transition matrix, the engine is then controlled to run according to the initial cylinder deactivation mode vector after switching to the second cylinder deactivation mode matrix.

7. The engine control method according to claim 1, characterized in that, Before acquiring the engine speed and torque during the current sub-cycle operation of the engine, the process further includes: After the engine is started, the cylinder deactivation condition zones of the engine under different numbers of cylinder deactivation are obtained; each cylinder deactivation condition zone includes a one-to-one corresponding cylinder deactivation mode matrix. Obtain the initial target speed and initial target torque of the engine; The corresponding initial target cylinder deactivation condition zone is determined based on the initial target speed and / or the initial target torque of the engine; Obtain the initial target cylinder deactivation mode matrix corresponding to the initial target cylinder deactivation condition zone; Obtain the cylinder deactivation mode vector that is initially executed after switching to the initial target cylinder deactivation mode matrix; The engine is controlled to operate according to the cylinder deactivation mode vector that is initially executed after switching to the initial target cylinder deactivation mode matrix.

8. The engine control method according to claim 7, wherein obtaining the cylinder deactivation operating range of the engine under different cylinder deactivation numbers includes: Obtain the advantageous operating conditions corresponding to each number of cylinders shut down; Each advantageous operating condition zone is divided at equal intervals along the speed dimension to obtain each cylinder deactivation operating condition zone included in each advantageous operating condition zone.

9. An engine control device, characterized in that, include: The speed-torque acquisition module is used to acquire the target speed and target torque of the engine during the process of the engine operating according to the current cylinder deactivation mode vector; The first judgment module is used to determine whether to switch the cylinder deactivation mode based on the target speed and / or the target torque. The target cylinder deactivation condition zone determination module is used to determine the target cylinder deactivation condition zone based on the target speed and / or target torque after the first judgment module determines the switching cylinder deactivation condition zone based on the target speed and / or target torque. The matrix determination module is used to obtain the cylinder deactivation mode matrix where the current cylinder deactivation mode vector is located and determine it as the first cylinder deactivation mode matrix, and to obtain the cylinder deactivation mode matrix corresponding to the target cylinder deactivation condition zone and determine it as the second cylinder deactivation mode matrix. The second judgment module is used to determine whether the first cylinder deactivation mode matrix and the second cylinder deactivation mode matrix are the same; The first switching information acquisition module is used to acquire a transition matrix and the initial cylinder stop mode vector after switching to the second cylinder stop mode matrix when the second judgment module determines that the first cylinder stop mode matrix and the second cylinder stop mode matrix are different. The first control module is used to control the engine to first run according to the transition matrix after the engine has finished running according to the current cylinder deactivation mode vector, and then run according to the cylinder deactivation mode vector that was initially run after switching to the second cylinder deactivation mode matrix. The first loop module is used to, after the first control module controls the engine to first run according to the transition matrix, and then run according to the cylinder deactivation mode vector initially running after switching to the second cylinder deactivation mode matrix, return to execute the step of obtaining the target speed and target torque of the engine during the process of the engine running according to the current cylinder deactivation mode vector.

10. An engine system, characterized in that, Includes a controller and multiple cylinders; The controller is used to execute the engine control method according to any one of claims 1 to 8.

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