Cylinder deactivation control method and system for engine and vehicle

文档序号：94372 发布日期：2021-10-12 浏览：44次中文

阅读说明：本技术 一种发动机的停缸控制方法、系统及车辆 (Cylinder deactivation control method and system for engine and vehicle ) 是由崔亚彬宋东先袁中营郭峰张秀珍于 2020-04-01 设计创作，主要内容包括：本发明提供了一种发动机的停缸控制方法、系统及车辆,其中,所述方法包括：发动机以随机停缸工作状态进行工作时,获取处于停缸状态的第一气缸的当前温度；若所述第一气缸的当前温度低于预设阈值,则控制所述第一气缸恢复至非停缸状态。本发明能够对处于停缸状态的气缸进行温度监测,并在停缸状态的气缸温度低于预设阈值时,控制对应气缸恢复至工作状态,使得对应气缸的温度可以提升,避免因为长时间的停缸导致停缸状态的气缸温度过低,造成气缸再次工作时燃烧效率过低、碳氢排放量过高的问题。(The invention provides a cylinder deactivation control method and system for an engine and a vehicle, wherein the method comprises the following steps: when the engine works in a random cylinder deactivation working state, acquiring the current temperature of a first cylinder in the cylinder deactivation state; and if the current temperature of the first cylinder is lower than a preset threshold value, controlling the first cylinder to recover to a non-cylinder deactivation state. The invention can monitor the temperature of the cylinder in the cylinder deactivation state, and control the corresponding cylinder to recover to the working state when the temperature of the cylinder in the cylinder deactivation state is lower than the preset threshold value, so that the temperature of the corresponding cylinder can be increased, and the problems of low combustion efficiency and high hydrocarbon emission when the cylinder works again due to the fact that the temperature of the cylinder in the cylinder deactivation state is too low caused by long-time cylinder deactivation are avoided.)

1. A cylinder deactivation control method of an engine, the method comprising:

when the engine works in a random cylinder deactivation working state, acquiring the current temperature of a first cylinder in the cylinder deactivation state;

and if the current temperature of the first cylinder is lower than a preset threshold value, controlling the first cylinder to recover to a non-cylinder deactivation state.

2. The method of claim 1, wherein obtaining the current temperature of the first cylinder in the deactivated state while the engine is operating in the random deactivated state comprises:

when the engine works in a random cylinder deactivation working state, acquiring the in-cylinder temperature of the first cylinder when the first cylinder starts to deactivate;

updating the in-cylinder temperature by using a first preset algorithm when the crankshaft of the engine rotates once;

and taking the updated in-cylinder temperature as the current temperature of the first cylinder.

3. The method of claim 2, wherein said updating said in-cylinder temperature with a first predetermined algorithm for each rotation of an engine crankshaft comprises:

when an engine crankshaft rotates once, acquiring the temperature in a cylinder after the previous rotation, the temperature of a cooling liquid during the current rotation and the circulating heat transfer time;

determining a temperature reduction value of the current rotation according to the temperature in the cylinder after the last rotation, the temperature of the cooling liquid and the circulating heat transfer time;

and subtracting the temperature reduction value from the cylinder temperature after the last rotation to obtain the updated cylinder temperature.

4. The method according to claim 3, wherein the determining the temperature decrease value for the current rotation from the in-cylinder temperature, the coolant temperature, and the cyclic heat transfer time after the previous rotation includes:

calculating the temperature difference of heat transfer according to the temperature in the cylinder and the temperature of the cooling liquid after the last rotation;

inquiring a preset heat transfer coefficient table according to the difference between the circulating heat transfer time and the heat transfer temperature to obtain a heat transfer coefficient; wherein, the heat transfer coefficient table is used for describing the corresponding relation between the cycle heat transfer time and the heat transfer temperature difference and the heat transfer coefficient;

and multiplying the temperature in the cylinder after the last rotation by the heat transfer coefficient to obtain a temperature reduction value.

5. The method of claim 2, wherein said obtaining an in-cylinder temperature at which said first cylinder begins to deactivate comprises:

acquiring the in-cylinder temperature of the first cylinder when the engine is started;

updating the temperature in the cylinder by using a second preset algorithm when the first cylinder does work once;

and taking the updated in-cylinder temperature as the in-cylinder temperature when the first cylinder starts to stop.

6. The method of claim 5, wherein said updating the in-cylinder temperature with a second predetermined algorithm for each work done by the first cylinder comprises:

when the first cylinder does work once, determining the temperature increment of the work, the temperature in the cylinder after the last work, the air inlet temperature and the dissipation temperature;

obtaining the engine speed and the torque of the first cylinder when doing work, and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work to obtain an experience coefficient, wherein the experience coefficient table is used for describing the corresponding relation between the engine speed and the torque and the experience coefficient;

and determining the temperature in the cylinder after the work is done this time according to the temperature increment, the temperature in the cylinder after the work is done last time, the air inlet temperature, the dissipation temperature and the empirical coefficient, and taking the temperature in the cylinder after the work is done this time as the updated temperature in the cylinder.

7. The method of claim 5, wherein said updating the in-cylinder temperature with a second predetermined algorithm for each work done by the first cylinder comprises:

acquiring the engine speed of the first cylinder when doing work this time and the oil injection quantity of the corresponding cylinder, and inquiring a preset temperature increment table according to the engine speed and the oil injection quantity to obtain a temperature increment; the temperature increment table is used for describing the corresponding relation between the engine speed and the fuel injection quantity and the temperature increment;

obtaining the temperature of a cooling liquid when the first cylinder does work at this time, the thermal resistance coefficient from a combustion chamber to a heat dissipation system and the final temperature in the cylinder 50 degrees before the top dead center when the first cylinder does work at the last time;

acquiring the temperature in the cylinder after the last work is done;

subtracting the temperature of the cooling liquid of the first cylinder when doing work at this time from the final temperature in the cylinder 50 degrees before the top dead center when doing work at the last time, and multiplying the temperature by a thermal resistance coefficient to obtain the dissipation temperature of the combustion chamber;

summing the temperature increment, the intake temperature and the temperature in the cylinder after the last work, and subtracting the dissipation temperature to obtain the final temperature in the cylinder at 50 degrees before the top dead center; and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work to obtain an experience coefficient, and multiplying the final in-cylinder temperature by the experience coefficient to obtain the in-cylinder temperature after doing work to serve as the updated in-cylinder temperature, wherein the experience coefficient table is used for describing the corresponding relation between the engine speed and the torque and the experience coefficient.

8. A cylinder deactivation control system of an engine, applied to a vehicle, characterized by comprising:

the temperature acquisition module is used for acquiring the current temperature of the first cylinder in the cylinder deactivation state when the engine works in the random cylinder deactivation working state;

and the control module is used for controlling the first cylinder to recover to a non-cylinder deactivation state if the current temperature of the first cylinder is lower than a preset threshold value.

9. The system of claim 8, wherein the temperature acquisition module comprises:

the first temperature submodule is used for acquiring the in-cylinder temperature of the first cylinder when the cylinder of the engine is stopped randomly when the engine works in the random cylinder stopping working state;

the updating submodule is used for updating the temperature in the cylinder by utilizing a first preset algorithm when the crankshaft of the engine rotates once;

and the second temperature submodule is used for taking the updated in-cylinder temperature as the current temperature of the first cylinder.

10. The system of claim 9, wherein the update submodule comprises:

the first temperature unit is used for acquiring the temperature in the cylinder after the previous rotation and the temperature of the cooling liquid during the current rotation when the crankshaft of the engine rotates once;

a second temperature unit for determining a temperature decrease value of the current rotation from the in-cylinder temperature after the previous rotation, the coolant temperature, and the cyclic heat transfer time;

and the first updating unit is used for subtracting the temperature reduction value from the cylinder temperature after the last rotation to obtain an updated cylinder temperature.

11. The system of claim 10, wherein the second temperature unit comprises:

the heat transfer temperature difference subunit is used for calculating the heat transfer temperature difference according to the temperature in the cylinder and the temperature of the cooling liquid after the last rotation;

the circulating heat transfer time subunit is used for acquiring the current rotating speed of the engine and calculating to obtain the circulating heat transfer time;

the heat transfer coefficient subunit is used for inquiring a preset heat transfer coefficient table according to the circulating heat transfer time and the heat transfer temperature difference to obtain a heat transfer coefficient; wherein, the heat transfer coefficient table is used for describing the corresponding relation between the cycle heat transfer time and the heat transfer temperature difference and the heat transfer coefficient;

and the temperature reduction value subunit is used for multiplying the temperature in the cylinder after the last rotation by the heat transfer coefficient to obtain a temperature reduction value.

12. The system of claim 9, wherein the first temperature sub-module comprises:

the third temperature unit is used for acquiring the in-cylinder temperature of the first cylinder when the engine is started;

the second updating unit is used for updating the temperature in the cylinder by using a second preset algorithm when the first cylinder does work once;

and the fourth temperature unit is used for taking the updated in-cylinder temperature as the in-cylinder temperature when the first cylinder starts to stop.

13. The system of claim 12, wherein the second updating unit comprises:

the temperature increment subunit is used for determining the temperature increment of the work when the first cylinder works once;

the air inlet temperature subunit is used for determining the air inlet temperature of the work when the first air cylinder does work every time;

the in-cylinder temperature unit is used for acquiring the in-cylinder temperature after the first cylinder applies work for each time;

the temperature loss subunit is used for determining the temperature loss of the work at this time when the first cylinder works once;

the experience coefficient subunit is used for acquiring the engine speed and the torque of the first cylinder when doing work, and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work to obtain an experience coefficient, wherein the experience coefficient table is used for describing the corresponding relation between the engine speed and the torque and the experience coefficient;

and the updating subunit is used for determining the temperature in the cylinder after the work is done this time according to the temperature increment, the temperature in the cylinder after the work is done last time, the air inlet temperature, the dissipation temperature and the experience coefficient, and taking the temperature in the cylinder after the work is done this time as the updated temperature in the cylinder.

14. The system of claim 13,

the temperature increment subunit is configured to obtain an engine speed of the first cylinder when doing work this time and an oil injection amount of the corresponding cylinder, and query a preset temperature increment table according to the engine speed and the oil injection amount to obtain a temperature increment; the temperature increment table is used for describing the corresponding relation between the engine speed and the fuel injection quantity and the temperature increment;

the temperature loss subunit is used for acquiring the temperature of the cooling liquid when the first cylinder does work this time, the thermal resistance coefficient from the combustion chamber to the heat dissipation system and the final temperature in the cylinder 50 degrees before the top dead center when the first cylinder does work last time; subtracting the temperature of the cooling liquid of the first cylinder when doing work at this time from the final temperature in the cylinder 50 degrees before the top dead center when doing work at the last time, and multiplying the temperature by a thermal resistance coefficient to obtain the dissipation temperature of the combustion chamber;

the updating subunit is used for summing the temperature increment, the intake temperature and the temperature in the cylinder after the last work, and subtracting the dissipation temperature to obtain the final temperature in the cylinder at 50 degrees before the top dead center; and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work to obtain an experience coefficient, and multiplying the final in-cylinder temperature by the experience coefficient to obtain the in-cylinder temperature after doing work to serve as the updated in-cylinder temperature.

15. A vehicle characterized by comprising the cylinder deactivation control system of an engine according to any one of claims 8 to 14.

Technical Field

The invention relates to the technical field of automobiles, in particular to a cylinder deactivation control method and system of an engine and a vehicle.

Background

At present, environmental problems and energy crisis are getting more and more serious, and the internal combustion engine is a large energy consumption household and a large pollution waste gas manufacturing household, so that the problem of energy conservation and emission reduction of the internal combustion engine is not slow enough.

Based on the purpose of reducing oil consumption, an engine cylinder deactivation technology is available at present, and a part of cylinders of an engine are closed when the engine works at low load so as to reduce pumping loss and friction, so that the engine is in a more economic oil consumption interval when the engine works at low load. For example, the conventional EA211 four-cylinder engine can control two cylinders to stop at low load, and the conventional 3.0 engine can control three cylinders or two symmetrical cylinders to stop at low load, so that the purpose of reducing oil consumption is achieved.

However, the current fixed cylinder deactivation technology of the engine can only select the cylinder deactivation function to be started or not to be started mechanically, after the cylinder deactivation is selected to be started, only the preset cylinders are stopped fixedly when the load of the engine is smaller than a certain preset value, and the engine is in a full-cylinder working state when the load of the engine is not smaller than the preset value, and the cylinder deactivation mode is too mechanical and rough, so that the full working condition of the engine cannot be in an optimal oil consumption area.

In order to solve the problem that the fixed cylinder deactivation is implemented too mechanically and roughly, so that the engine cannot be in the optimal oil consumption area under all working conditions, the engine capable of randomly deactivating the cylinder is provided, when the engine works under a small load, part of working cylinders can be randomly closed, the torque output by the working cylinders which continuously work can meet the target torque requirement of the engine, and because part of the working cylinders are closed, the displacement of the engine is reduced, so that the pumping loss and the friction loss can be reduced, and the engine can realize the optimal working condition oil consumption as much as possible.

However, in the random cylinder deactivation engine, after the working cylinder receives the operation stop command, the intake and exhaust valves are closed, the fuel injection ignition is stopped, the pressure in the cylinder is negative at the moment, and only part of the combusted waste gas remains. The in-cylinder heat atmosphere is lower and lower as the coolant gradually takes away the in-cylinder heat. When the cylinder which stops working recovers oil injection to work, because the heat in the cylinder is low, the fuel oil which is combusted for the first time can not be well atomized, the combustion efficiency is low, and the THC (total hydrocarbon) which is discharged is high; and the longer the time that the cylinder is stopped, the lower the combustion efficiency of the first combustion at the time of resuming the operation, and the higher the THC emission.

Disclosure of Invention

In view of the above, the present invention aims to provide a cylinder deactivation control method and system for an engine, and a vehicle, so as to solve the problems of low first combustion efficiency and high total amount of discharged hydrocarbon when a cylinder which is easy to stop working in the conventional random cylinder deactivation engine resumes working.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a cylinder deactivation control method of an engine, applied to a vehicle, wherein the method comprises:

when the engine works in a random cylinder deactivation working state, acquiring the current temperature of a first cylinder in the cylinder deactivation state;

and if the current temperature of the first cylinder is lower than a preset threshold value, controlling the first cylinder to recover to a working state.

Optionally, the method, when the engine is operated in the random cylinder deactivation operating state, acquiring a current temperature of the first cylinder in the shutdown state, includes:

when the engine works in a random cylinder deactivation working state, acquiring the in-cylinder temperature of the first cylinder when the first cylinder starts to deactivate;

updating the in-cylinder temperature by using a first preset algorithm when the crankshaft of the engine rotates once;

and taking the updated in-cylinder temperature as the current temperature of the first cylinder.

Optionally, the method, wherein the updating the in-cylinder temperature with a first preset algorithm every revolution of an engine crankshaft, comprises:

determining the temperature reduction value of the current rotation according to the temperature in the cylinder, the temperature of the cooling liquid and the circulating heat transfer time after the previous rotation;

and subtracting the temperature reduction value from the cylinder temperature after the last rotation to obtain the updated cylinder temperature.

Optionally, in the method, the determining a temperature decrease value of the current rotation from the in-cylinder temperature, the coolant temperature, and the cyclic heat transfer time after the previous rotation includes:

calculating the temperature difference of heat transfer according to the temperature in the cylinder and the temperature of the cooling liquid after the last rotation;

and multiplying the temperature in the cylinder after the last rotation by the heat transfer coefficient to obtain a temperature reduction value.

Optionally, in the method, the obtaining the in-cylinder temperature of the first cylinder at the time of starting cylinder deactivation includes:

acquiring the in-cylinder temperature of the first cylinder when the engine is started;

updating the temperature in the cylinder by using a second preset algorithm when the first cylinder does work once;

and taking the updated in-cylinder temperature as the in-cylinder temperature when the first cylinder starts to stop.

Optionally, in the method, the updating the in-cylinder temperature by using a second preset algorithm every time the first cylinder performs work includes:

determining the temperature increment, the inlet air temperature and the dissipation temperature of the work when the first cylinder does work every time;

and determining the updated in-cylinder temperature according to the temperature increment, the intake air temperature, the dissipation temperature and the empirical coefficient.

Optionally, in the method, the updating the in-cylinder temperature by using a second preset algorithm every time the first cylinder performs work includes:

acquiring the temperature in the cylinder after the last work is done;

and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work to obtain an experience coefficient, and multiplying the final in-cylinder temperature by the experience coefficient to obtain the in-cylinder temperature after doing work to serve as the updated in-cylinder temperature, wherein the experience coefficient table is used for describing the corresponding relation between the engine speed and the torque and the experience coefficient.

The invention provides a cylinder deactivation control system of an engine, which is applied to a vehicle, wherein the system comprises:

Optionally, in the system, the temperature obtaining module includes:

the updating submodule is used for updating the temperature in the cylinder by utilizing a first preset algorithm when the crankshaft of the engine rotates once;

and the second temperature submodule is used for taking the updated in-cylinder temperature as the current temperature of the first cylinder.

Optionally, in the system, the update sub-module includes:

and the first updating unit is used for subtracting the temperature reduction value from the cylinder temperature after the last rotation to obtain an updated cylinder temperature.

Optionally, in the system, the second temperature unit includes:

the heat transfer temperature difference subunit is used for calculating the heat transfer temperature difference according to the temperature in the cylinder after the last rotation and the temperature of the cooling liquid;

the circulating heat transfer time subunit is used for acquiring the current rotating speed of the engine and calculating to obtain the circulating heat transfer time;

and the temperature reduction value subunit is used for multiplying the temperature in the cylinder after the last rotation by the heat transfer coefficient to obtain a temperature reduction value.

Optionally, in the system, the first temperature sub-module includes:

the third temperature unit is used for acquiring the in-cylinder temperature of the first cylinder when the engine is started;

the second updating unit is used for updating the temperature in the cylinder by using a second preset algorithm when the first cylinder does work once;

and the fourth temperature unit is used for taking the updated in-cylinder temperature as the in-cylinder temperature when the first cylinder starts to stop.

Optionally, in the system, the second updating unit includes:

the temperature increment subunit is used for determining the temperature increment of the work when the first cylinder works once;

the air inlet temperature subunit is used for determining the air inlet temperature of the work when the first air cylinder does work every time;

the temperature loss subunit is used for determining the temperature loss of the work at this time when the first cylinder works once;

and the updating subunit is used for determining the updated in-cylinder temperature according to the temperature increment, the intake air temperature, the dissipation temperature and the empirical coefficient.

Optionally, in the system as described,

the updating subunit is used for summing the temperature increment, the intake temperature and the temperature in the cylinder after the last work, and subtracting the dissipation temperature to obtain the final temperature in the cylinder at 50 degrees before the top dead center; and inquiring a preset experience coefficient table according to the engine speed and the torque of the first cylinder when doing work so to obtain an experience coefficient, and multiplying the final in-cylinder temperature by the experience coefficient to obtain an updated in-cylinder temperature.

Compared with the prior art, the cylinder deactivation control method and system of the engine have the following advantages:

when the engine is in a random cylinder deactivation working state, the current temperature of the first cylinder in a shutdown state is acquired, and when the current temperature of the first cylinder is lower than a preset threshold value, the first cylinder is controlled to be recovered to a non-cylinder deactivation state. Because can carry out temperature monitoring to the first cylinder that is in the jar state of stopping to when the first cylinder temperature of jar state of stopping is less than preset threshold value, the control corresponds first cylinder and resumes to non-jar-stopping state, makes the temperature of first cylinder can promote, avoids leading to the cylinder temperature of jar state of stopping excessively because long-time jar of stopping, and the combustion efficiency is low excessively when causing the cylinder to work once more, problem that hydrocarbon emission is too high.

The invention also provides a vehicle, wherein the vehicle comprises the cylinder deactivation control system of the engine.

The vehicle and the engine cylinder deactivation control method have the same advantages compared with the prior art, and the detailed description is omitted.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a flowchart of a method for controlling cylinder deactivation of an engine according to an embodiment of the present invention;

FIG. 2 is a schematic view of a combustion temperature increase process of a cylinder in the embodiment of the invention;

FIG. 3 is a schematic diagram illustrating a cylinder cooling process in cylinder deactivation in an embodiment of the present invention;

FIG. 4 is a functional block diagram of a cylinder deactivation control system for an engine in accordance with an embodiment of the present invention.

Detailed Description

Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While embodiments of the present application are illustrated in the accompanying drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In this embodiment, the operating state of the engine is divided into a full-cylinder operating state and a random cylinder deactivation operating state. The all-cylinder working state is a state that all cylinders of the engine work; the random cylinder deactivation working state means that when a driver accelerates or decelerates to switch torques, the vehicle can control the engine to work at different cylinder deactivation rates and cylinder deactivation sequences according to different torques, namely the vehicle can randomly control part of cylinders to stop working according to different torque requirements so as to work with the fewest cylinders on the premise of meeting the torque requirements, and the engine can achieve the best working condition oil consumption as much as possible.

The random cylinder deactivation working state can save the energy consumption of the engine, and the principle thereof is as follows:

in the working process of the engine, the piston is pushed to rotate by consuming fuel oil, but the energy generated by the consumed fuel oil is used for pushing the piston to rotate the crankshaft, part of the energy is taken away by high-temperature tail gas and cooling water, part of the energy is used for overcoming the friction resistance to work, and part of the energy is used for overcoming the pumping loss. Further, the larger the engine displacement, the greater the capacity loss due to friction and pumping loss, and therefore, the same torque is output and the smaller the energy loss of the small displacement engine to overcome friction and pumping loss is than that of the large displacement engine. Therefore, if the engine is controlled to operate at a low load, that is, when the target torque is small, the torque output by the cylinders which are partially closed and are ensured to continue operating can meet the target torque demand of the engine, and since the partial cylinders are closed, which corresponds to the reduction of the displacement of the engine, the pumping loss and the friction loss can be reduced.

It can be seen that the working principle of the random cylinder deactivation working state is equivalent to dynamically adjusting the displacement of the engine according to different working conditions, thereby realizing the reduction of the energy consumption of the engine.

In order to realize the random cylinder deactivation working state, each cylinder of the engine is provided with an intake valve, an exhaust valve, an oil nozzle and an ignition device which can be independently opened and closed, so that the intake and the exhaust of any cylinder can be stopped by closing the intake valve and the exhaust valve at any time, and the ignition and the oil injection are simultaneously stopped, thereby realizing the random cylinder deactivation effect.

Specifically, the control process of the random cylinder deactivation of the embodiment may include: acquiring a target torque of an engine; determining whether a random cylinder deactivation working state needs to be entered; if the random cylinder deactivation working state needs to be entered, determining the running state of the vehicle; when the running state of the vehicle is a steady state, determining a target cylinder deactivation rate corresponding to the target torque according to the target torque; when the running state of the vehicle is transient, determining a target cylinder deactivation rate corresponding to the target torque according to the target torque and the acceleration and deceleration state of the vehicle; the acceleration and deceleration state comprises an acceleration state and a deceleration state, and the target cylinder deactivation rate corresponding to the acceleration state is greater than the target cylinder deactivation rate corresponding to the deceleration state; and controlling the engine to work according to the target cylinder deactivation rate.

The method comprises the following steps that different cylinder deactivation rates correspond to different outer characteristic curve graphs, the outer characteristic curve graphs are determined by torque and engine rotating speed, and a preset optimal oil consumption area is arranged in the outer characteristic curve graphs and is obtained in advance according to actual use. Because the outer characteristic curve chart is determined by the torque and the engine rotating speed, and the preset optimal oil consumption area is arranged in the outer characteristic curve chart, after the condition that the engine needs to enter the random cylinder deactivation working state is determined, the corresponding target cylinder deactivation rate is determined according to the target torque and the current rotating speed, so that the target torque is in the optimal oil consumption area of the outer characteristic curve chart, the target torque can be input into the engine, and the engine can work in the optimal oil consumption state on the premise of outputting the target torque, so that the oil consumption is saved.

In addition, a cylinder deactivation table corresponding to the target cylinder deactivation rate can be obtained according to the preset corresponding relation between the cylinder deactivation rate and the cylinder deactivation table; the cylinder deactivation table is preset with the number of cylinders deactivated in a plurality of working cycles and the cylinder sequence of cylinder deactivation. And controlling the engine to work according to the number of cylinders deactivated in a plurality of working cycles in the cylinder deactivation table and the cylinder sequence of cylinder deactivation. On the basis of meeting the target cylinder deactivation rate, the engine can be controlled to perform cylinder deactivation according to a cylinder deactivation table. The cylinder deactivation table may take into account noise, vibration, and harshness factors to minimize vibration when the engine is operating at the same cylinder deactivation rate.

Referring to FIG. 1, a flowchart illustrating steps of a method for controlling cylinder deactivation of an engine according to the present embodiment is shown. The embodiment takes a vehicle as an execution carrier of the whole scheme.

And S100, when the engine works in the random cylinder deactivation working state, acquiring the current temperature of the first cylinder in the cylinder deactivation state.

After the cylinder stops working, the air inlet and outlet valves of the cylinder are closed, oil injection and ignition are stopped, negative pressure exists in the cylinder at the moment, only part of combusted waste gas is remained, and the cooling liquid continuously cools the cylinder, so that the hot atmosphere in the cylinder is lower and lower, and the hot atmosphere is continuously reduced to gradually reach the temperature balance with the cooling liquid; if the cylinder with cylinder deactivation is controlled to be recovered to a working state, fuel oil can not be well atomized easily during the first fuel injection combustion due to low in-cylinder heat separation, so that the combustion efficiency is low, the THC (total hydrocarbon) discharged is high, and the longer the cylinder deactivation time is, the lower the first combustion efficiency during the combustion recovery is, the higher the THC discharge is.

Therefore, in this step, if it is detected that the engine operates in the random cylinder deactivation operating state, it indicates that some cylinders stop operating in one or more operating cycles of the engine and are in the cylinder deactivation state, and at this time, the temperature of all the first cylinders in the cylinder deactivation state is monitored, and the corresponding current temperature is obtained, so as to determine whether the current temperature reaches a state that affects the first fuel injection and combustion efficiency when the subsequent cylinders resume operating.

And S200, if the current temperature of the first cylinder is lower than a preset threshold value, controlling the first cylinder to recover to a non-cylinder-deactivation state.

In the step, the preset threshold value is a temperature approach value which causes insufficient fuel atomization when the cylinder recovers to work and performs first fuel injection combustion; when the temperature of the cylinder is higher than the preset threshold value for oil injection and combustion, the fuel oil can be sufficiently atomized, the combustion efficiency of the fuel oil is high, and the total amount of carbon and hydrogen in exhaust gas is low; when the temperature of the cylinder is lower than the preset threshold value for fuel injection and combustion, the fuel cannot be completely atomized, the combustion efficiency of the fuel is low, and the total amount of carbon and hydrogen in exhaust gas is high. The preset threshold value can be obtained through experimental verification in advance.

In this step, if the temperature of the cylinder in the cylinder deactivation state in the engine is lower than the preset threshold, it indicates that the current temperature of the cylinder is about to reach a state that affects the first fuel injection and combustion efficiency when the cylinder subsequently recovers to work, and therefore the corresponding cylinder needs to be controlled to recover to the working state. When the temperature of the cylinder in the cylinder deactivation state is lower than a preset threshold value, the cylinder is required to recover to work no matter whether the cylinder deactivation rate is changed or not, and oil injection and ignition are started. When the temperature of the cylinder in the cylinder deactivation state in the engine is lower than the preset threshold value, if the cylinder deactivation working state is continuously kept, the cooling liquid can continuously take away heat in the cylinder of the cylinder in the cylinder deactivation state, so that the temperature of the cylinder is continuously reduced, the atomization effect of fuel oil during the first fuel injection and combustion when the cylinder recovers to work is further influenced, the combustion efficiency of the fuel oil is also influenced, and the total amount of generated hydrocarbon in exhaust gas is higher; if the cylinder is controlled to be recovered to a non-cylinder-stop working state, namely, the states of air intake, oil injection ignition, working and exhaust according to the working cycle of the engine are recovered, the temperature of the cylinder can be increased before the temperature of the cylinder is reduced to the atomization effect of fuel oil during the first oil injection combustion when the cylinder recovers to work, so that the problems that when the fuel oil is injected again and combusted due to overlong cylinder-stop time, the fuel oil is insufficiently atomized due to too low temperature in the cylinder, the combustion efficiency is too low, and the total amount of carbon and hydrogen in exhaust is too high can be avoided.

Optionally, the embodiment of the present invention further includes the steps of: and if the current temperature of the first cylinder is not lower than a preset threshold value, controlling the first cylinder to keep a cylinder deactivation state.

In the step, because the temperature of the cylinder in the cylinder deactivation state when the cylinder deactivation operation state is operated at random is monitored, if the current temperature is not lower than the preset threshold value, the temperature in the cylinder does not affect the first fuel atomization effect when the cylinder resumes operation, and therefore, the corresponding cylinder can be continuously controlled to maintain the cylinder deactivation state according to the requirement of the random cylinder deactivation operation, and better energy saving and emission reduction effects can be achieved.

In the embodiment of the invention, when the engine is in the random cylinder deactivation working state, if any cylinder of the engine is in the cylinder deactivation state, the current temperature of the corresponding cylinder is acquired, and when the current temperature of the corresponding cylinder is lower than a preset threshold value, the corresponding cylinder is controlled to be recovered to the working state. Because can carry out temperature monitoring to the cylinder that is in the stall state to when the cylinder temperature of stall state is less than preset threshold value, control corresponds the cylinder and resumes to operating condition, make the temperature that corresponds the cylinder can promote, avoid leading to the cylinder temperature of stall state to hang down excessively because long-time stall, cause the cylinder to work once more the problem that combustion efficiency is low excessively, hydrocarbon emission is too high.

Since it is difficult to directly acquire the in-cylinder temperature of the engine cylinder, but it can be acquired indirectly, therefore, in an embodiment, the step S100 includes the steps S110 to S130 to indirectly acquire the in-cylinder temperature after each rotation of the engine, that is, the in-cylinder temperature after each cycle of the cylinder piston in the cylinder deactivation state, and to approximate the current temperature of the cylinder in the cylinder deactivation state with the temperature.

And step S110, acquiring the in-cylinder temperature of the first cylinder when the first cylinder starts to be deactivated when the engine operates in the random cylinder deactivation working state.

In the step, namely when the engine works in the random cylinder deactivation working state, the in-cylinder temperature of any first cylinder in the cylinder deactivation state when starting cylinder deactivation is obtained.

Alternatively, the in-cylinder temperature at the time of starting the cylinder deactivation may be indirectly obtained by the exhaust gas temperature of the cylinder or the like.

Alternatively, the in-cylinder temperature at the time of cylinder deactivation of the first cylinder may be acquired through steps S111 to S113.

And step S111, acquiring the in-cylinder temperature of the first cylinder when the engine is started.

The in-cylinder temperature of the first cylinder at the time of start of the engine, that is, the temperature at which the engine starts operating. If the engine is started after the complete machine is completely cooled, the temperature in the first cylinder at the time of starting the engine can be approximated to the temperature of the coolant at the time of starting the engine because the temperature of the cylinder and the temperature of the coolant reach a balanced state.

And S112, updating the temperature in the cylinder by using a second preset algorithm when the first cylinder does work once.

In the step, because factors influencing the temperature change in the cylinder, such as the temperature of the cooling liquid, the cooling time, the temperature increment during each work, the temperature taken away by exhaust gas and the like, consider that the time of the cylinder during each work is very short, the temperature in the cylinder can be correspondingly updated according to the work frequency, namely the temperature value of the closest real temperature in the cylinder can be obtained, and meanwhile, the calculated amount is greatly reduced.

Optionally, the step S112 includes steps S1121 to S1123.

Step S1121, determining the temperature increment, the intake temperature and the dissipation temperature of the work at this time when the first cylinder performs work every time.

Specifically, in step S1121, by obtaining the engine speed of the first cylinder when doing work this time and the fuel injection quantity of the corresponding cylinder, a preset temperature increment table is queried according to the engine speed and the fuel injection quantity to obtain a temperature increment; the temperature increment table is used for describing the corresponding relation between the engine speed and the fuel injection quantity and the temperature increment.

In this step, the temperature increment is determined by the engine speed and the fuel injection amount when the cylinder does work, that is, the temperature increment has a corresponding relationship with the engine speed and the fuel injection amount when the cylinder does work, and the corresponding relationship is different among different cylinders. Therefore, in the embodiment of the invention, the corresponding relation between the engine speed and the fuel injection quantity and the temperature increment is determined in advance through tests, and a temperature increment table is constructed for different cylinders, wherein the temperature increment table is used for describing the corresponding relation between the temperature increment and the engine speed and the fuel injection quantity; then, in this step, after the engine speed and the fuel injection quantity are obtained, a preset temperature increment table corresponding to the first cylinder is called, and the engine speed and the fuel injection quantity are input, so that the corresponding temperature increment can be obtained.

In the embodiment of the invention, the abscissa of the temperature increment table is the engine speed, the ordinate is the fuel injection quantity, and the content is the temperature increment. The preset temperature increment table can be obtained through a plurality of tests of the engine, and the embodiment of the invention does not limit the preset temperature increment table.

Specifically, in step S1121, the intake air temperature may be directly obtained by monitoring the temperature of the intake air.

Specifically, in step S1121, the dissipation temperature may be obtained in the following manner: obtaining the temperature of a cooling liquid of the first cylinder when doing work at this time, the thermal resistance coefficient from a combustion chamber to a heat dissipation system and the final temperature in the cylinder 50 degrees before the top dead center when doing work at the last time; acquiring the temperature in the cylinder after the last work is done; subtracting the temperature of the cooling liquid of the first cylinder when doing work at this time from the final temperature in the cylinder 50 degrees before the top dead center when doing work at the last time, and multiplying the temperature by a thermal resistance coefficient to obtain the dissipation temperature of the combustion chamber; and simultaneously, summing the temperature increment, the intake temperature and the temperature in the cylinder after the last work application to obtain a theoretical temperature in the cylinder 50 degrees before the top dead center, and subtracting the dissipation temperature from the theoretical temperature in the cylinder 50 degrees before the top dead center to obtain a final temperature in the cylinder 50 degrees before the top dead center.

Step S1122, obtaining the rotating speed and the torque of the engine when the first cylinder does work this time, and inquiring a preset experience coefficient table according to the rotating speed and the torque of the engine when the first cylinder does work this time to obtain an experience coefficient, wherein the experience coefficient table is used for describing the corresponding relation between the rotating speed and the torque of the engine and the experience coefficient.

In the step, because the cylinder needs to do work outwards, overcome friction, exhaust and the like when doing work each time, a part of gas and energy are necessarily taken away, so that the temperature in the cylinder is reduced, and then the temperature in the cylinder after doing work once can be obtained. The current rotation speed and torque of the engine affect the temperature drop proportion in the cylinder, and the relationship can be represented by empirical coefficients, and meanwhile, the empirical coefficients of different cylinders are different, so that an empirical coefficient table representing the corresponding relationship between the rotation speed and torque of the engine and the empirical coefficients needs to be established in advance through experiments. In the step, after the rotating speed and the torque of the engine are obtained, the empirical coefficient table corresponding to the first cylinder is called, and the rotating speed and the torque of the engine are input and obtained, so that the heat transfer coefficient can be obtained.

In the embodiment of the invention, the abscissa of the empirical coefficient table is the rotating speed, the ordinate is the torque, and the content is the empirical coefficient. The preset empirical coefficient table may be obtained through multiple tests of the engine, and the embodiment of the present invention is not limited thereto.

And step S1123, determining the updated in-cylinder temperature according to the temperature increment, the intake air temperature, the dissipation temperature and the empirical coefficient.

Specifically, referring to fig. 2, the dissipated temperature is subtracted from the sum of the temperature increment, the intake air temperature, and the cylinder temperature after the last work, and then multiplied by the empirical coefficient to obtain the cylinder temperature after the work is done this time, and the temperature is determined as the updated cylinder temperature.

And step S113, taking the updated in-cylinder temperature as the in-cylinder temperature when the first cylinder starts to stop.

The cylinder deactivation working state of the engine cylinder is always started after the cylinder performs one complete work, so that the in-cylinder temperature updated in the previous step can be used as the in-cylinder temperature when the first cylinder starts to deactivate.

And step S120, updating the in-cylinder temperature by utilizing a first preset algorithm when the crankshaft of the engine rotates once.

In the step, because the factors influencing the temperature change in the cylinder after the cylinder enters the cylinder deactivation state are only the temperature of the cooling liquid and the cooling time, and the time of the engine crankshaft rotating once is considered to be short, the temperature in the cylinder after the cylinder deactivation can be correspondingly updated according to the rotating frequency of the crankshaft, the temperature value which is closest to the real temperature in the cylinder can be obtained, and meanwhile, the calculated amount is greatly reduced.

Specifically, the step S120 includes steps S210 to S230.

And step S210, when the crankshaft of the engine rotates once, acquiring the temperature in the cylinder after the previous rotation, the temperature of the cooling liquid during the current rotation and the circulating heat transfer time.

In the step, the temperature of the cooling liquid can be directly obtained by detecting the temperature of the cooling liquid through a temperature sensor, and the circulating heat transfer time, namely the time required by the current rotation, can be directly obtained from the current rotating speed of the engine. And the temperature in the cylinder after the last rotation is obtained through updating the temperature in the cylinder after the last rotation until the temperature in the cylinder when the first cylinder starts to stop the cylinder.

And step S220, determining a temperature reduction value of the current rotation according to the temperature in the cylinder after the last rotation, the temperature of the cooling liquid and the circulating heat transfer time.

Because the factors affecting the cylinder temperature in the cylinder deactivation state include the current in-cylinder temperature (i.e., the in-cylinder temperature after the last rotation), the coolant temperature, and the heat transfer cycle time, the temperature decrease value after the current rotation of the crankshaft can be determined from the in-cylinder temperature after the last rotation, the coolant temperature, and the heat transfer cycle time.

Specifically, in this step, step S220 includes steps S221 to S223.

And step S221, calculating the heat transfer temperature difference according to the temperature in the cylinder and the temperature of the cooling liquid after the last rotation.

In this step, the temperature of the cooling liquid is directly subtracted from the temperature in the cylinder after the previous rotation, and the heat transfer temperature difference of the crankshaft during the current rotation is obtained.

And step S222, inquiring a preset heat transfer coefficient table according to the circulating heat transfer time and the heat transfer temperature difference. Obtaining a heat transfer coefficient; wherein, the heat transfer coefficient table is used for describing the corresponding relation between the cycle heat transfer time and the heat transfer temperature difference and the heat transfer coefficient.

In this step, the heat transfer coefficient represents the temperature drop amplitude of the cylinder in the cylinder deactivation state after the crankshaft rotates once, the heat transfer coefficient is related to both the cycle heat transfer time and the heat transfer temperature difference, and the heat transfer temperature difference and the cycle heat transfer time are different when the crankshaft rotates once, so that a heat transfer coefficient table needs to be constructed in advance according to the corresponding relationship among the cycle heat transfer time, the heat transfer temperature difference and the heat transfer coefficient, and the heat transfer coefficient table is used for describing the corresponding relationship among the heat transfer coefficient, the cycle heat transfer time and the heat transfer temperature difference. Considering that the corresponding relations of different cylinders may be different, corresponding heat transfer coefficient tables can be constructed for different cylinders; then, in this step, after the heat transfer time and the heat transfer temperature difference are obtained, the heat transfer coefficient table corresponding to the first cylinder is called, and the heat transfer temperature difference and the heat transfer time are input, so that the corresponding heat transfer coefficient can be obtained.

In the embodiment of the invention, the abscissa of the heat transfer coefficient table is the heat transfer temperature difference, the ordinate is the circulating heat transfer time, and the content is the heat transfer coefficient. The preset heat transfer coefficient table may be obtained through a plurality of tests on the engine, and the embodiment of the present invention does not limit the same.

For example, the heat transfer coefficient table in step S222 described above may be as shown in table 1:

TABLE 1

In table 1, the abscissa is the heat transfer temperature difference, the ordinate is the cycle heat transfer time, and the content is the heat transfer coefficient.

For example, in practical applications, if the current heat transfer temperature difference is 100 ℃ and the cycle heat transfer time is 0.01s, the heat transfer coefficient is 0.001 as can be found by using table 1; if the current heat transfer temperature difference is 300 deg.c and the cycle heat transfer time is 0.1s, the heat transfer coefficient can be found to be 0.02 using table 1.

And S223, multiplying the temperature in the cylinder after the last rotation by the heat transfer coefficient to obtain a temperature reduction value.

And step S230, subtracting the temperature reduction value from the cylinder temperature after the last rotation to obtain an updated cylinder temperature.

In this step, the temperature decrease value taken away by the coolant is subtracted from the in-cylinder temperature after the previous rotation, and the updated in-cylinder temperature can be obtained.

Referring to fig. 3, in the engine temperature reduction process in the cylinder deactivation state, as shown in fig. 3, due to the cooling liquid circulation cooling, the final in-cylinder temperature of the cylinder in the cylinder deactivation state is continuously reduced, and the temperature reduction value is obtained by multiplying the heat transfer coefficient determined by the heat transfer temperature difference formed by the current in-cylinder temperature and the cooling liquid temperature and the current circulation heat transfer time by the in-cylinder temperature.

And step S130, taking the updated in-cylinder temperature as the current temperature of the first cylinder.

In this step, the updated in-cylinder temperature is used as the current temperature of the corresponding first cylinder to represent the latest in-cylinder temperature state, so as to determine whether the current temperature reaches a preset threshold value, and determine whether to control the corresponding cylinder to resume the working state or continue to maintain the cylinder deactivation state.

In summary, according to the cylinder deactivation control method for the engine provided in the embodiments of the present invention, when the target torque of the engine changes, whether the target state information meets the preset condition is determined by at least one of the current rotation speed, the current gear, the water temperature, the accumulated working time, the water temperature, the current oil pressure, and the accelerator pedal angle of the engine, so as to determine whether the engine enters the random cylinder deactivation working state or the full cylinder working state, rather than being determined by the load of the engine, and therefore, the problems that the driving of the vehicle is affected after the cylinder deactivation and the use requirement cannot be met can be avoided.

On the basis of the embodiment, the embodiment of the invention also provides a cylinder deactivation control system of the engine.

Referring to fig. 4, a block diagram of a cylinder deactivation control system of an engine, which is applied to a vehicle, according to an embodiment of the present invention is shown, wherein the system includes:

the temperature acquisition module 10 is used for acquiring the current temperature of the first cylinder in the cylinder deactivation state when the engine works in the random cylinder deactivation working state;

the control module 20 is configured to control the first cylinder to return to a non-cylinder deactivation state if the current temperature of the first cylinder is lower than a preset threshold.

Optionally, in the system, the temperature obtaining module 10 includes:

the updating submodule is used for updating the temperature in the cylinder by utilizing a first preset algorithm when the crankshaft of the engine rotates once;

and the second temperature submodule is used for taking the updated in-cylinder temperature as the current temperature of the first cylinder.

Optionally, in the system, the update sub-module includes:

the second temperature unit is used for determining a temperature reduction value of the current rotation according to the temperature in the cylinder, the temperature of the cooling liquid and the circulating heat transfer time;