CN111878214A - Method and system for adaptive control of piston cooling nozzle - Google Patents

Abstract

The application relates to a self-adaptive control method and a system for a piston cooling nozzle, wherein the method comprises the following steps: when the engine is powered on, running or stopped, the piston cooling nozzle is closed by default; judging whether the engine oil temperature is lower than a closing temperature limit value in real time; when the engine oil temperature is less than the shutdown temperature limit, it is determined whether to open the piston cooling nozzle based on engine speed, load, knock, and pre-ignition. The application provides a piston cooling nozzle self-adaptation control method, the frequent opening and closing of the piston cooling nozzle that single factor triggered when having avoided the engine operating mode to change is avoided overheating risk's emergence, is favorable to prolonging the life-span of piston cooling nozzle and electronic control valve simultaneously.

Description

Method and system for adaptive control of piston cooling nozzle

technical field

The present application relates to the field of engine control, and in particular, to a method and system for adaptive control of a piston cooling nozzle.

Background technique

The engine lubricating system plays the role of providing lubrication and protection for the oilers of various engine systems. Piston cooling nozzles are installed on the engine to reduce the thermal load of the piston and strengthen the lubrication of the piston pin connecting rod bearing.

In the prior art, the opening and closing of the piston cooling nozzle is controlled according to the calibration relationship curve between the opening and closing of the cooling nozzle and the parameters of rotational speed, torque (load) and oil temperature; and the opening and closing of the piston cooling nozzle is controlled when knocking and pre-ignition occur. .

However, in fact, the changes of engine speed and load are sudden changes, and the frequency of opening and closing of the piston cooling nozzle is too frequent, which leads to frequent intermittent cooling of the piston, which leads to the risk of overheating and affects the life of the piston cooling nozzle and electronic control valve.

SUMMARY OF THE INVENTION

Embodiments of the present application provide an adaptive control method and system for a piston cooling nozzle, so as to solve the problem in the related art that the frequency of opening and closing of the piston cooling nozzle is too frequent, which causes the risk of overheating and reduces the life of the piston cooling nozzle and the electronic control valve. .

On the one hand, an embodiment of the present application provides an adaptive control method for a piston cooling nozzle, which includes the following steps:

When the engine is powered on, running or stopped, the piston cooling nozzle is closed by default;

Get the engine oil temperature;

Determine whether the engine oil temperature is lower than the shutdown temperature limit;

When the engine oil temperature is lower than the shutdown temperature limit, it is determined whether to open the piston cooling nozzle according to the engine speed, load, knocking and pre-ignition conditions.

In some embodiments, after judging whether the engine oil temperature is lower than the shutdown temperature limit, the following steps are further included:

When the engine oil temperature exceeds the opening temperature limit, the piston cooling nozzle is opened;

When the engine oil temperature is between the closing temperature limit and the opening temperature limit, the current opening and closing state of the piston cooling nozzle is maintained unchanged.

In some embodiments, when the engine oil temperature is lower than the shutdown temperature limit, determining whether to open the piston cooling nozzle according to the engine speed, load, knocking and pre-ignition conditions specifically includes the following steps:

Perform first-order low-pass filtering on the engine speed at the current moment to obtain the filtered engine speed;

Perform first-order low-pass filtering on the engine load at the current moment to obtain the filtered engine load;

Determine whether to open the piston cooling nozzle according to the filtered engine speed, the filtered engine load and the corresponding mapping table;

Real-time judgment of whether the engine has knocking or pre-ignition;

In the event of knocking or pre-ignition, the piston cooling jets are turned on.

In some embodiments, performing first-order low-pass filtering processing on the engine speed at the current moment to obtain the filtered engine speed specifically includes the following steps:

When the current engine speed is greater than the filtered engine speed at the previous moment, according to n(N)=C1×[n _Act -n(N-1)]+n(N-1), the engine speed at time N is calculated by one Order low-pass filtering processing, where N=1, 2, 3..., n(N-1) is the engine speed after filtering at time N-1; n(N) is the engine speed after filtering at time N; at this time, The first-order low-pass filter coefficient is the engine speed filter coefficient C1, the time difference between time N-1 and time N is the fixed update period ΔT; n _Act is the actual engine speed at time N;

When the current engine speed is not greater than the filtered engine speed at the previous moment, filter the engine speed at time N according to n(N)=C2×[n _Act -n(N-1)]+n(N-1) processing, where N=1, 2, 3..., n(N-1) is the filtered engine speed at time N-1; n(N) is the filtered engine speed at time N; at this time, the first-order low The pass filter coefficient is the engine speed filter coefficient C2, the time difference between time N-1 and time N is the fixed update period ΔT; n _Act is the actual engine speed at time N, C1>C2, 0<C1<1, 0<C2<1 .

In some embodiments, performing first-order low-pass filtering processing on the engine load at the current moment to obtain the filtered engine load specifically includes the following steps:

When the current engine load is greater than the filtered engine load at the previous moment, the first-order low-pass filtering process is performed on the engine load at the N moment according to the following formula:

rho(N)=C3×[rho _Act -rho(N-1)]+rho(N-1), where N=1,2,3..., rho(N-1) is the time at the time of N-1 Filtered engine load; rho(N) is the filtered engine load at time N; at this time, the first-order low-pass filter coefficient is the engine speed filter coefficient C3, and the time difference between time N-1 and time N is the fixed update period ΔT; rho _Act is the actual engine load at time N;

If the current engine load is not greater than the filtered engine load at the previous moment, the first-order low-pass filtering process is performed on the engine load at the N moment according to the following formula:

rho(N)=C4×[rho _Act -rho(N-1)]+rho(N-1), where N=1,2,3..., rho(N-1) is the time at the time of N-1 Filtered engine load; rho(N) is the filtered engine load at time N; at this time, the first-order low-pass filter coefficient is the engine load filter coefficient C4, and the time difference between time N-1 and time N is the fixed update period ΔT; rho _Act is the actual engine load at time N, where C3>C4, 0<C3<1, and 0<C4<1.

In some embodiments, the determining whether to open the piston cooling nozzle according to the filtered engine speed, the filtered engine load and the corresponding mapping table specifically includes the following steps:

Establish engine speed and engine load mapping table;

Look up the above mapping table according to the filtered engine speed to determine the upper limit value of the engine load for opening the piston cooling nozzle, and look up the mapping table according to the filtered engine speed to determine the lower limit value of the engine load for closing the piston cooling nozzle;

When the filtered engine load is greater than the upper limit of the engine load, the piston cooling nozzle is opened;

When the filtered engine load is between the lower limit value of the engine load and the upper limit value of the engine load, the open and closed state of the piston cooling nozzle remains unchanged at the current state;

When the filtered engine load is less than the lower limit of the engine load, the piston cooling nozzle is turned on or off according to the knock and pre-ignition conditions.

In some embodiments, once knocking or pre-ignition occurs, after the piston cooling nozzle is opened, the following steps are further included:

Determine whether the engine has high-intensity knocking;

When high-intensity knocking occurs, open the piston cooling nozzle and update the upper limit of the engine load at the current filter speed, subtract a load correction value from the upper limit of the engine load, and at the current filter speed due to high-intensity knocking The upper limit value of the engine load is updated one or more times, and the initial value is restored after the engine is powered off.

In some embodiments, once knocking or pre-ignition occurs, after the piston cooling nozzle is opened, the following steps are further included:

Accumulate the number of engine pre-ignitions under different filtered engine speeds and different filtered engine loads;

When the number of pre-ignitions under a certain filter speed and filter load exceeds the limit value of the number of times, the upper limit value of the engine load at the current filter speed is updated while the piston cooling nozzle is opened, and a load correction value is subtracted from the upper limit value of the load. And the load upper limit value at the current filter speed is updated one or more times due to pre-ignition, and the initial value is restored after the engine is powered off;

If the number limit is not exceeded, the upper load limit is not updated and only the piston cooling jets are turned on.

In some embodiments, when the piston cooling nozzle is turned on to off, the PWM duty cycle control is set to 0 after delaying a preset value for a period of time.

On the other hand, an embodiment of the present application also provides a system applying the above-mentioned adaptive control method for a piston cooling nozzle, which includes an oil pump, a temperature sensor, a piston cooling nozzle, an electronic control valve and a controller, the oil pump is configured to oil is supplied to the engine; a temperature sensor is configured to detect the temperature of the engine oil, piston cooling nozzles are configured to direct a jet of oil from the engine to a piston of the engine; an electronic control valve is configured to control the piston oil flow to the cooling jets; the controller is configured to control the electronically controlled valve to provide a flow rate to the piston cooling jets at a flow rate above a threshold flow rate when the temperature sensor measures an engine oil temperature exceeding an opening temperature limit oil to achieve opening of the piston cooling nozzle;

maintaining a constant flow rate of oil from the electronically controlled valve to the piston cooling jets when the temperature sensor measures the temperature of the engine oil between the opening temperature limit and the closing temperature limit; and

When the temperature sensor measures the temperature of the engine oil below the shut-off temperature limit, the controller determines whether it is necessary to control the electronic control valve to provide flow to the piston cooling nozzle based on engine speed, load, knock and pre-ignition conditions A flow rate of oil above a threshold flow rate to achieve opening of the piston cooling jets.

In some embodiments, the system further includes a rotational speed detection unit, a load detection unit, a knock detection unit, a pre-ignition detection unit and a counter, the rotational speed detection unit is configured to detect the rotational speed of the engine; the load detection unit is configured to detect The load of the engine; the knock detection unit is configured to detect the knock condition of the engine; the pre-ignition detection unit is configured to detect the pre-ignition condition of the engine; the counter is configured to count the number of pre-ignitions; the controller receives the rotational speed detection unit, the load detection unit unit, the knock detection unit, the pre-ignition detection unit and the counter's rotational speed information, load information, knock information, pre-ignition information, and pre-ignition times, which are used according to the rotational speed information, load information, knock information, pre-ignition information and The number of pre-ignitions controls whether the electronic control valve provides oil with a flow rate higher than a threshold flow rate to the piston cooling nozzle, so as to realize the opening of the piston cooling nozzle.

The beneficial effects brought by the technical solution provided by this application include:

Embodiments of the present application provide an adaptive control method and system for a piston cooling nozzle. By detecting engine oil in real time, when it is lower than a shutdown temperature limit, it is determined whether to Open the piston cooling nozzle, therefore, avoid the frequent opening and closing of the piston cooling nozzle triggered by a single factor when the engine operating conditions change, avoid the risk of overheating caused by intermittent and frequent operation of the piston cooling nozzle, and is conducive to extending the piston cooling nozzle and electronic Control valve life.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 is a flowchart of an adaptive control method for a piston cooling nozzle provided by an embodiment of the present application;

FIG. 2 is a functional block diagram of a piston cooling nozzle adaptive control system provided by an embodiment of the present application.

In the figure: 1, oil pump; 2, engine; 31, rotational speed detection unit; 32, load detection unit; 33, knock detection unit; 34, pre-ignition detection unit; 35, counter; 4, controller; 5, electronic control valve; 6. Piston cooling nozzle.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, 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 It is a part of the embodiments of this application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present application.

The embodiments of the present application provide an adaptive control method and system for the piston cooling nozzle 6, which can solve the problem that the frequency of opening and closing of the piston cooling nozzle 6 in the related art is too frequent, which causes the risk of overheating and reduces the electronic pressure of the piston cooling nozzle 6. The problem of the life of the control valve 5.

On the one hand, an embodiment of the present application provides an adaptive control method for the piston cooling nozzle 6, which includes the following steps:

When the engine 2 is powered on, running or stopped, the piston cooling nozzle 6 is closed by default;

Get engine 2 oil temperature;

Determine whether the oil temperature of engine 2 is lower than the shutdown temperature limit;

When the engine oil temperature of the engine 2 is lower than the shutdown temperature limit, it is determined whether to open the piston cooling nozzle 6 according to the engine speed, load, knocking and pre-ignition conditions.

It can be known that the electronic control valve 5 of the piston cooling nozzle 6 controls the opening and closing of the piston cooling nozzle 6 . The electronic control valve 5 is controlled by PWM. The larger the PWM duty ratio is, the longer the control piston cooling nozzle 6 is opened per unit time; the smaller the PWM duty ratio is, the shorter the control piston cooling nozzle 6 is opened per unit time. When the PWM is 100%, the piston cooling nozzle 6 is always on; when the PWM is 0%, the piston cooling nozzle 6 is always off.

As described above, according to the present application, when the piston cooling nozzle 6 is turned on, the PWM is a fixed duty cycle PWM _Max , and PWM _Max is less than or equal to 100%.

In some embodiments, after judging whether the oil temperature of the engine 2 is lower than the shutdown temperature limit, the following steps are further included:

When the oil temperature of the engine 2 exceeds the opening temperature limit, the piston cooling nozzle 6 is opened;

When the oil temperature of the engine 2 is between the closing temperature limit and the opening temperature limit, the current open and closed state of the piston cooling nozzle 6 is maintained.

In some embodiments, when the engine oil temperature of the engine 2 is lower than the shutdown temperature limit, determining whether to open the piston cooling nozzle 6 according to the engine speed, load, knocking and pre-ignition conditions specifically includes the following steps:

The first-order low-pass filtering process is performed on the engine speed at the current moment to obtain the filtered engine speed, which is used to suppress the sudden change of the engine speed and the frequent intermittent cooling of the piston, which leads to the risk of overheating and reduces the life of the electronic control valve 5 of the piston cooling nozzle 6;

First-order low-pass filtering is performed on the engine load at the current moment to obtain the filtered engine load, which is used to suppress the sudden change of the engine load condition and cause frequent intermittent cooling of the piston, resulting in the risk of overheating and reducing the life of the piston cooling nozzle 6 and the electronic control valve 5;

Determine whether to open the piston cooling nozzle 6 according to the filtered engine speed, the filtered engine load and the corresponding mapping table;

Determine in real time whether the engine 2 has knocking or pre-ignition;

In the event of knocking or pre-ignition, the piston cooling jets 6 are opened.

In some embodiments, performing first-order low-pass filtering processing on the engine speed at the current moment to obtain the filtered engine speed specifically includes the following steps:

When the current engine speed is greater than the filtered engine speed at the previous moment, according to n(N)=C1×[n _Act -n(N-1)]+n(N-1), the engine speed at time N is calculated by one Order low-pass filtering processing, where N=1, 2, 3..., n(N-1) is the engine speed after filtering at time N-1; n(N) is the engine speed after filtering at time N; at this time, The first-order low-pass filter coefficient is the engine speed filter coefficient C1, the time difference between time N-1 and time N is the fixed update period ΔT; n _Act is the actual engine speed at time N;

When the current engine speed is not greater than the filtered engine speed at the previous moment, filter the engine speed at time N according to n(N)=C2×[n _Act -n(N-1)]+n(N-1) processing, where N=1, 2, 3..., n(N-1) is the filtered engine speed at time N-1; n(N) is the filtered engine speed at time N; at this time, the first-order low The pass filter coefficient is the engine speed filter coefficient C2, the time difference between time N-1 and time N is a fixed update period ΔT; n _Act is the actual engine speed at time N, where the smaller the filter coefficient C1 or C2, the smoother the engine speed, And C1>C2, that is, when the engine speed decreases, it can more truly reflect its changes, 0<C1<1, 0<C2<1.

In some embodiments, performing first-order low-pass filtering processing on the engine load at the current moment to obtain the filtered engine load specifically includes the following steps:

When the current engine load is greater than the filtered engine load at the previous moment, the first-order low-pass filtering process is performed on the engine load at the N moment according to the following formula:

rho(N)=C3×[rho _Act -rho(N-1)]+rho(N-1), where N=1,2,3..., rho(N-1) is the time at the time of N-1 Filtered engine load; rho(N) is the filtered engine load at time N; at this time, the first-order low-pass filter coefficient is the engine speed filter coefficient C3, and the time difference between time N-1 and time N is the fixed update period ΔT; rho _Act is the actual engine load at time N;

If the current engine load is not greater than the filtered engine load at the previous moment, the first-order low-pass filtering process is performed on the engine load at the N moment according to the following formula:

rho(N)=C4×[rho _Act -rho(N-1)]+rho(N-1), where N=1,2,3..., rho(N-1) is the time at the time of N-1 Filtered engine load; rho(N) is the filtered engine load at time N; at this time, the first-order low-pass filter coefficient is the engine load filter coefficient C4, and the time difference between time N-1 and time N is the fixed update period ΔT; rho _Act is the actual engine load at time N, where C3>C4, 0<C3<1, 0<C4<1, the smaller the filter coefficient C3 or C4, the smoother the engine load, and C3>C4, that is, when the engine load decreases, more realistically reflect its changes.

As mentioned above, according to the present application, the purpose of C1 being greater than C2 is the same as that of C3 being greater than C4, in order to delay the moment when the piston cooling nozzle 6 is switched from opening to closing to reduce the risk of overheating of the piston and C1 is greater than C3 and C2 is greater than C4 Since it has been found through experiments that changes in engine speed relative to changes in load have a more significant effect on the increase in piston temperature, it is necessary to further reduce the risk of overheating of the piston cooling nozzles 6 caused by fluctuations in engine speed. The reason for the smaller filter factor when the engine speed or load is reduced is to delay the moment when the piston cooling jets 6 are switched from opening to closing, reducing the risk of piston overheating.

In some embodiments, the determining whether to open the piston cooling nozzle 6 according to the filtered engine speed, the filtered engine load and the corresponding mapping table specifically includes the following steps:

Establish engine speed and engine load mapping table;

According to the filtered engine speed, the above mapping table is used to determine the upper limit value of the engine load at which the piston cooling nozzle 6 is opened, and the lower limit value of the engine load at which the piston cooling nozzle 6 is closed is determined by referring to the map table according to the filtered engine speed. ;

When the filtered engine load is greater than the upper limit of the engine load, the piston cooling nozzle 6 is opened;

When the filtered engine load is between the lower limit value of the engine load and the upper limit value of the engine load, the open and closed state of the piston cooling nozzle 6 maintains the current state unchanged;

When the filtered engine load is less than the lower limit value of the engine load, the piston cooling nozzle 6 is turned on or off according to the knocking and pre-ignition conditions.

In some embodiments, once knocking or pre-ignition occurs, after the piston cooling nozzle 6 is opened, the following steps are further included:

Determine whether high-intensity knocking occurs in engine 2;

When a high-intensity knock occurs, the piston cooling nozzle 6 is opened and the upper limit of the engine load at the current filter speed is updated, a load correction value is subtracted from the upper limit of the engine load, and the current filter speed caused by the high-intensity knock The lower engine load upper limit value is updated one or more times, and the initial value is restored after the engine 2 is powered off. It is used to increase the opening area of the piston cooling nozzle 6 during high-intensity knocking, and further reduce the risk of knocking and overheating of the piston. In order to overcome the technical defect that only controlling the opening of the piston cooling nozzle 6 can not necessarily reduce the risk of overheating when high-intensity knocking of the supercharged engine 2 occurs.

As described above, according to the present application, judging whether high-intensity knocking occurs in the engine 2 specifically includes the following steps:

Under a certain filter speed and filter load (n _K (N), rho _K (N)), the ignition angle change of the knock retardation is not less than the difference between the ignition angle before the knock retardation and the minimum ignition angle setting value; When knocking occurs under a certain filter speed and filter load (n _K (N), rho _K (N)), the ignition angle change of knock delay reaches the set value of the maximum ignition angle change of knock delay , at least one of the two conditions is satisfied, and the engine has high-intensity knocking.

In some embodiments, once knocking or pre-ignition occurs, after the piston cooling nozzle 6 is opened, the following steps are further included:

Accumulate the number of pre-ignition times of engine 2 under different filtered engine speeds and different filtered engine loads;

When the number of pre-ignitions under a certain filter speed and filter load exceeds the limit value of the number of times, the upper limit value of the engine load at the current filter speed is updated while the piston cooling nozzle 6 is opened, and a load correction value is subtracted from the upper limit value of the load. , and the load upper limit value under the current filter speed is updated one or more times due to pre-ignition, and the initial value is restored after the engine 2 is powered off; when the number of pre-ignitions is large, the area where the piston cooling nozzle 6 is opened is increased, The risk of overheating of the piston due to pre-ignition is further reduced. In order to overcome the technical defect that only controlling the opening of the piston cooling nozzle 6 can not necessarily reduce the risk of overheating when the number of pre-ignition frequently occurs.

If the number of times limit is not exceeded, the load upper limit value is not updated, and only the piston cooling nozzle 6 is turned on.

In some embodiments, when the piston cooling nozzle 6 is turned on to off, the PWM duty cycle of the electronic control valve 5 of the piston cooling nozzle 6 is set to PWM _Medium after a period of time T _Medium , and PWM _Low is set after a period of time T _Low , set The PWM duty cycle is 0; the time T _Medium and the time T _Low are both preset delay time values. When the piston cooling nozzle 6 is opened to close, the duty cycle control delays the preset value for a period of time and is set to 0, is used to delay closing the piston cooling nozzle 6 when the engine speed or load decreases, and the transition control further prevents the risk of overheating from the immediate cooling of the piston cooling.

On the other hand, referring to FIG. 2 , an embodiment of the present application also provides a system applying the above method, which includes an oil pump 1 , a temperature sensor, a piston cooling nozzle 6 , an electronic control valve 5 and a controller 4 , the oil pump 1 is configured to supply oil to the engine 2; a temperature sensor is configured to detect the temperature of the oil of the engine 2, piston cooling nozzles 6 are configured to direct a jet of oil from said engine 2 to the pistons of said engine 2; electronically controlled valve 5 is configured to control the flow of oil to the piston cooling nozzles 6; the controller 4 is configured to control the electronic control valve 5 to control the electronic control valve 5 when the temperature of the oil in the engine 2 measured by the temperature sensor exceeds the opening temperature limit. The piston cooling nozzle 6 provides oil with a flow rate higher than a threshold flow rate to realize opening of the piston cooling nozzle 6; when the temperature sensor measures the temperature of the engine oil 2 between the opening temperature limit and the closing temperature limit When the flow rate of the oil supplied by the electronic control valve 5 to the piston cooling nozzle 6 is kept constant; and when the temperature of the oil in the engine 2 measured by the temperature sensor is lower than the shut-off temperature limit, the controller 4 is based on the engine speed, load, explosion Shock and pre-ignition conditions are used to determine whether the electronic control valve 5 needs to be controlled to supply oil with a flow rate higher than a threshold flow rate to the piston cooling nozzle 6 to realize opening of the piston cooling nozzle 6 .

In some embodiments, please refer to FIG. 2 , the system further includes a rotational speed detection unit 31 , a load detection unit 32 , a knock detection unit 33 , a pre-ignition detection unit 34 and a counter 35 , the rotational speed detection unit 31 is configured to detect The rotational speed of the engine 2; the load detection unit 32 is configured to detect the load of the engine 2; the knock detection unit 33 is configured to detect the knocking condition of the engine 2; the pre-ignition detection unit 34 is configured to detect the pre-ignition condition of the engine 2; The counter 35 is configured to count the number of pre-ignitions; the controller 4 receives the rotational speed information, load information, knocking information, Pre-ignition information and pre-ignition times, used to control whether the electronic control valve 5 provides oil with a flow rate higher than the threshold flow rate to the piston cooling nozzle 6 according to the rotational speed information, load information, knock information, pre-ignition information and pre-ignition times , so as to open the piston cooling nozzle 6 .

Improve the influence of sudden changes in the engine 2 operating conditions on the control of the piston cooling nozzle 6 through engine speed and load, and delay closing the piston cooling nozzle 6 when the engine speed or load decreases, reducing the risk of piston overheating; and when pre-ignition and knocking occur The piston cooling nozzle 6 is opened, and when high-intensity knocking and pre-ignition are many times, the opening area of the piston cooling nozzle 6 is increased to further reduce the risk of piston overheating caused by knocking and pre-ignition.

In the description of this application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the application and simplifying the description, Rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and controlled in a particular orientation, it should not be construed as a limitation of the present application. Unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, It can also be an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or an internal connection between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

It should be noted that in this application, relational terms such as "first" and "second" etc. are only used to distinguish one entity or control from another entity or control, and do not necessarily require or imply that Any such actual relationship or sequence exists between these entities or controls. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above descriptions are only specific embodiments of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, this application is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims (10)

1. A method for adaptive control of a piston cooling nozzle, comprising the steps of:

when the engine is powered on, running or stopped, the piston cooling nozzle is closed by default;

obtaining the temperature of engine oil of an engine;

judging whether the engine oil temperature is lower than a closing temperature limit value or not;

when the engine oil temperature is less than the shutdown temperature limit, determining whether to open the piston cooling nozzle based on engine speed, load, knock, and pre-ignition.

2. The adaptive piston cooling nozzle control method as recited in claim 1, further comprising the step of, after determining whether the engine oil temperature is below a shutdown temperature limit:

when the temperature of engine oil exceeds the opening temperature limit value, the piston cooling nozzle is opened;

and when the temperature of the engine oil is between the closing temperature limit value and the opening temperature limit value, maintaining the current opening and closing state of the piston cooling nozzle unchanged.

3. The adaptive piston cooling nozzle control method as claimed in claim 1, wherein the step of determining whether to open the piston cooling nozzle based on engine speed, load, knock and pre-ignition when the engine oil temperature is below a shut-off temperature limit comprises the steps of:

performing first-order low-pass filtering processing on the rotating speed of the engine at the current moment to obtain the filtered rotating speed of the engine;

carrying out first-order low-pass filtering processing on the engine load at the current moment to obtain the filtered engine load;

determining whether to open a piston cooling nozzle according to the filtered engine speed, the filtered engine load and a corresponding mapping table;

judging whether the engine knocks or pre-ignites in real time;

upon occurrence of knocking or pre-ignition, the piston cooling nozzle is opened.

4. The adaptive control method for the piston cooling nozzle according to claim 3, wherein the step of performing first-order low-pass filtering on the engine speed at the current moment to obtain the filtered engine speed comprises the following steps:

after filtering when the current engine speed is greater than the last momentAccording to the engine speed of (1), based on n (N) ═ C1 × [ n × [_Act-n(N-1)]+ N (N-1), performing first-order low-pass filtering processing on the engine speed at the time of N, wherein N is 1,2,3, and N (N-1) is the engine speed after filtering at the time of N-1; n (N) is the filtered engine speed at time N; at the moment, the first-order low-pass filter coefficient is an engine speed filter coefficient C1, and the time difference between the time N-1 and the time N is a fixed updating period delta T; n is_ActActual engine speed at time N;

when the current engine speed is not greater than the filtered engine speed at the previous time, according to n (N) ═ C2 × [ n ]_Act-n(N-1)]+ N (N-1) performing filtering processing on the engine speed at the time N, wherein N is 1,2,3, and N (N-1) is the filtered engine speed at the time N-1; n (N) is the filtered engine speed at time N; at the moment, the first-order low-pass filter coefficient is an engine speed filter coefficient C2, and the time difference between the time N-1 and the time N is a fixed updating period delta T; n is_ActActual engine speed at time N, C1 > C2, 0<C1<1，0<C2<1。

5. The adaptive control method for a piston cooling nozzle according to claim 4, wherein the step of performing first-order low-pass filtering on the engine load at the current moment to obtain a filtered engine load comprises the following steps:

when the current engine load is larger than the filtered engine load at the previous moment, performing first-order low-pass filtering processing on the engine load at the N moment according to the following formula:

rho(N)＝C3×[rho_Act-rho(N-1)]+ rho (N-1), where N ═ 1,2,3, rho (N-1) is the filtered engine load at time N-1; rho (N) is the filtered engine load at time N; at the moment, the first-order low-pass filter coefficient is an engine speed filter coefficient C3, and the time difference between the moment N-1 and the moment N is a fixed updating period delta T; rho (rho)_ActActual engine load at time N;

if the current engine load is not greater than the filtered engine load at the previous moment, performing first-order low-pass filtering processing on the engine load at the N moment according to the following formula:

rho(N)＝C4×[rho_Act-rho(N-1)]+ rho (N-1), where N ═ 1,2,3, rho (N-1) is the filtered engine load at time N-1; rho (N) is the filtered engine load at time N; at the moment, the first-order low-pass filter coefficient is an engine load filter coefficient C4, and the time difference between the time N-1 and the time N is a fixed updating period delta T; rho (rho)_ActActual engine load at time N, where C3 > C4, 0<C3<1，0<C4<1。

6. The adaptive piston cooling nozzle control method according to claim 5, wherein the determining whether to open the piston cooling nozzle according to the filtered engine speed, the filtered engine load and the corresponding map comprises the steps of:

establishing an engine speed and engine load mapping table;

checking the mapping table according to the filtered engine rotation speed to determine the upper limit value of the engine load for opening the piston cooling nozzle, and checking the mapping table according to the filtered engine rotation speed to determine the lower limit value of the engine load for closing the piston cooling nozzle;

when the engine load after filtering is greater than the engine load upper limit value, the piston cooling nozzle is opened;

when the filtered engine load is between the engine load lower limit value and the engine load upper limit value, the opening and closing state of the piston cooling nozzle is kept unchanged;

and when the filtered engine load is smaller than the lower limit value of the engine load, opening or closing the piston cooling nozzle according to the conditions of knocking and pre-ignition.

7. The adaptive piston cooling nozzle control method as recited in claim 3, further comprising the step of, after the piston cooling nozzle is opened upon occurrence of a detonation or pre-ignition:

judging whether the engine knocks with high intensity;

when high-intensity knocking occurs, the current filtering rotating speed n is updated while a piston cooling nozzle is opened_K(N) belowAn upper limit value of the engine load, which is subtracted by a load correction value and at which the current filtered speed n is due to high intensity knock_SAnd (N) updating the upper limit value of the engine load for one time or more times, and recovering the initial value after the engine is powered off.

8. The adaptive piston cooling nozzle control method as recited in claim 3, further comprising the step of, after the piston cooling nozzle is opened upon occurrence of a detonation or pre-ignition:

accumulating the rotating speed of the engine after different filtering and the pre-ignition times of the engine under different engine loads after different filtering;

when the pre-ignition times under a certain filtering rotating speed and filtering load exceed the times limit value, updating the upper limit value of the engine load under the current filtering rotating speed while opening the piston cooling nozzle, subtracting a load correction value from the upper limit value of the load, updating the upper limit value of the load under the current filtering rotating speed once or for many times due to the pre-ignition, and recovering the initial value after the engine is powered off;

if the number of times limit is not exceeded, the upper load limit is not updated and only the piston cooling nozzles are opened.

9. The adaptive control method for the piston cooling nozzle as claimed in claim 1, wherein the PWM duty control is set to 0 after a delay for a predetermined time from the opening to the closing of the piston cooling nozzle.

10. A system for applying the adaptive control method for a piston cooling nozzle according to any one of claims 1 to 9, comprising:

an oil pump configured to provide oil to an engine;

a temperature sensor configured to detect a temperature of engine oil,

a piston cooling nozzle configured to direct a jet of oil from the engine towards a piston of the engine; and

an electronically controlled valve configured to control oil flow to the piston cooling nozzle; and

a controller configured to:

when the temperature sensor measures that the temperature of engine oil exceeds an opening temperature limit, controlling the electronically controlled valve to provide oil to the piston cooling nozzle at a flow rate above a threshold flow rate to effect opening of the piston cooling nozzle;

maintaining a constant flow rate of oil supplied by the electronically controlled valve to the piston cooling nozzle when the temperature sensor measures a temperature of engine oil between an open temperature limit and a closed temperature limit; and

when the temperature sensor measures that the temperature of engine oil is below a shut-off temperature limit, a controller determines whether it is necessary to control the electronically controlled valve to provide oil to the piston cooling nozzle at a flow rate above a threshold flow rate to effect opening of the piston cooling nozzle based on engine speed, load, knock, and pre-ignition conditions.

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