阅读说明：本技术 活塞内冷油道冷却效率的检测装置和检测方法 (Detection device and detection method for cooling efficiency of cold oil duct in piston ) 是由 汤海威 魏涛 许成 刘建华 宋建正 刘志超 李磊 王凝露 于 2021-09-14 设计创作，主要内容包括：本发明提供一种活塞内冷油道冷却效率的检测装置和检测方法,检测装置包括曲柄连杆机构、加热机构、进油机构、回油机构；曲柄连杆机构用于与活塞的底部连接,用于驱动活塞上下往复运动；加热机构用于设置在活塞顶部,用于对活塞顶部加热；进油机构用于与活塞底部连接,进油机构用于给活塞内部喷射机油,进油机构的进油管路上设有进油温度传感器；回油机构用于与活塞的内冷油道连通,用于收集从内冷油道中流出的机油,回油机构的回油管路上还设有回油温度传感器和流量计。本发明提供的活塞内冷油道冷却效率的检测装置和检测方法,用于解决仅通过检测活塞冷却喷嘴的打靶效率不能真实地获得内冷油道冷却效率的问题。(The invention provides a detection device and a detection method for cooling efficiency of a cold oil duct in a piston, wherein the detection device comprises a crank connecting rod mechanism, a heating mechanism, an oil inlet mechanism and an oil return mechanism; the crank connecting rod mechanism is connected with the bottom of the piston and used for driving the piston to reciprocate up and down; the heating mechanism is arranged at the top of the piston and used for heating the top of the piston; the oil inlet mechanism is used for being connected with the bottom of the piston and used for injecting engine oil into the piston, and an oil inlet temperature sensor is arranged on an oil inlet pipeline of the oil inlet mechanism; the oil return mechanism is communicated with the inner cooling oil duct of the piston and used for collecting engine oil flowing out of the inner cooling oil duct, and an oil return temperature sensor and a flowmeter are further arranged on an oil return pipeline of the oil return mechanism. The invention provides a detection device and a detection method for cooling efficiency of an inner cooling oil duct of a piston, which are used for solving the problem that the cooling efficiency of the inner cooling oil duct cannot be really obtained only by detecting the targeting efficiency of a cooling nozzle of the piston.)

1. A detection device for the cooling efficiency of a piston inner cooling oil duct is used for detecting the piston inner cooling oil duct and is characterized by comprising a crank connecting rod mechanism, a heating mechanism, an oil inlet mechanism and an oil return mechanism;

the crank connecting rod mechanism is connected with the bottom of the piston and used for driving the piston to reciprocate up and down;

the heating mechanism is arranged at the top of the piston and used for heating the top of the piston;

the oil inlet mechanism is used for being connected with the bottom of the piston and used for injecting engine oil into the piston, and an oil inlet temperature sensor is arranged on an oil inlet pipeline of the oil inlet mechanism;

the oil return mechanism is used for being communicated with the inner cooling oil duct of the piston, the oil return mechanism is used for collecting engine oil flowing out of the inner cooling oil duct, and an oil return temperature sensor and a flowmeter are further arranged on an oil return pipeline of the oil return mechanism.

2. The apparatus for detecting cooling efficiency of an oil cooling passage in a piston according to claim 1, wherein the crank-link mechanism includes a motor, a crankshaft, a connecting rod, a bearing;

the motor is connected to one end of the crankshaft through the bearing, the connecting rod is connected to the crankshaft in the radial direction, and power of the motor is converted into vertical reciprocating motion of the connecting rod;

the other end of the connecting rod is connected with the bottom of the piston and drives the piston to reciprocate up and down.

3. The apparatus for detecting cooling efficiency of an oil cooling passage in a piston according to claim 2, wherein said crank mechanism further comprises: a guide rail;

the piston is at least connected with two sliding blocks, through holes are formed in the sliding blocks, and the sliding blocks penetrate through the through holes and are arranged on the guide rail.

4. The apparatus for detecting cooling efficiency of an oil cooling passage in a piston according to claim 3, wherein said heating mechanism includes: the device comprises a heater, an insulating thermal baffle and a limiting sleeve;

the heater is arranged at the upper part of the piston, and the periphery of the heater is connected with the insulating heat-insulating plate;

the insulation heat insulation plate is provided with at least two limiting sleeves, through holes are formed in the limiting sleeves, and the limiting sleeves are arranged on the guide rails in a sliding mode.

5. The apparatus for detecting cooling efficiency of the cooling oil passage in the piston as claimed in claim 4, wherein the heating mechanism further comprises a heat transfer module, the heat transfer module is used for being arranged between the piston and the heater;

the upper surface and the lower surface of the heat transfer module are respectively attached to the lower surface of the heater and the upper surface of the piston.

6. The device for detecting the cooling efficiency of the cold oil passage in the piston as claimed in claim 4, wherein the heating mechanism further comprises at least one limiting block, the limiting block is arranged below the insulated heat insulation board, and when the limiting sleeve drives the heater to move downwards, the lower surface of the insulated heat insulation board abuts against the limiting block and stops moving.

7. The device for detecting the cooling efficiency of the cold oil passage in the piston as claimed in any one of claims 4 to 6, wherein a return spring is further arranged on the limiting sleeve, and the return spring is arranged on the guide rail in a penetrating manner and used for returning the heater when the heater operates downwards.

8. The device for detecting the cooling efficiency of the cold oil passage in the piston as claimed in any one of claims 1 to 6, wherein the device further comprises a base, and an oil tank and a radiator are arranged on the base;

the oil tank is used for conveying and collecting the engine oil entering and exiting from the oil inlet mechanism and the oil return mechanism;

the radiator set up in around the oil tank, the oil tank bottom still is equipped with the heater.

9. A method for detecting the cooling efficiency of an internal cooling oil passage of a piston, which is used for detecting the cooling effect of the internal cooling oil passage of the piston, and is characterized in that the method is detected by any one of the devices for detecting the cooling efficiency of the internal cooling oil passage of the piston 1 to 8, and the method comprises the following steps:

a crank connecting rod mechanism is adopted to drive the piston to reciprocate up and down;

heating the top of the piston by a heating mechanism;

an oil inlet temperature sensor and an oil return temperature sensor are respectively arranged on the oil inlet pipeline and the oil return pipeline, and the temperature difference of engine oil entering and exiting the piston is measured;

a flowmeter is arranged on the oil return pipeline to detect the flow of the return oil;

the heat Q taken away by the engine oil from the inner cooling oil duct is obtained according to the following heat calculation formula by the engine oil temperature and the oil return flow: and Q is c m Δ t, c is the specific heat capacity of the engine oil, m is the return oil flow measured by the flowmeter, and Δ t is the temperature difference of the engine oil.

10. A method for evaluating the cooling efficiency of a cooling oil passage in a piston, which is detected by the device for detecting the cooling efficiency of a cooling oil passage in a piston according to any one of the above items 1 to 8, the method comprising:

a crank connecting rod mechanism is adopted to drive the piston to reciprocate up and down;

heating the top of the piston by a heating mechanism;

installing temperature sensors on the piston top and the piston skirt, and measuring the temperature of the piston top and the piston skirt;

and evaluating the cooling effect of the inner cooling oil channel on the piston according to the difference value between the temperature of the top of the piston and the temperature of the skirt part of the piston.

Technical Field

The invention relates to the technical field of internal combustion engines, in particular to a device and a method for detecting cooling efficiency of a cooling oil duct in a piston.

Background

The piston reciprocates at a high speed in the cylinder body and is in a high-temperature combustion gas environment, so that the temperature of the piston is higher, the top of the piston needs to be cooled by arranging the internal cooling oil duct inside the piston, engine oil is sprayed into the internal cooling oil duct by arranging the internal cooling oil duct inside the piston, the engine oil violently vibrates under the high-speed reciprocating motion of the piston after entering the internal cooling oil duct, most heat of the piston can be taken away in the vibrating process of the engine oil in the internal cooling oil duct, and the temperature of the top of the piston is reduced.

In the related art, in order to detect the cooling efficiency of the internal cooling oil duct on the piston, flowmeters are usually arranged in front of a piston cooling nozzle and at an oil return position of an internal cooling oil cavity of the piston, or a weighing mode is adopted, when the piston and the cooling nozzle are in static positions, the flow rates of engine oil when the piston enters and exits are measured, and the targeting efficiency of the piston cooling nozzle is obtained through the ratio of the oil quantity sprayed into the internal cooling oil duct of the piston by the piston cooling nozzle to the total oil quantity sprayed out by the piston cooling nozzle in unit time.

And calculating the target shooting efficiency of the piston cooling nozzle through detection, and judging the cooling effect of the piston according to the target shooting efficiency. However, the above method can only measure the flow rate before and after passing through the piston, and cannot really obtain the cooling efficiency of the inner cooling oil passage on the piston.

Disclosure of Invention

The invention provides a device and a method for detecting the cooling efficiency of an internal cooling oil duct of a piston, which are used for solving the problem that the cooling efficiency of the piston by the internal cooling oil duct cannot be really obtained by detecting and calculating the targeting efficiency of a cooling nozzle of the piston and reflecting the cooling effect of the piston in the prior art.

In order to achieve the purpose, the invention provides a device for detecting the cooling efficiency of a piston inner cooling oil duct, which is used for detecting the piston inner cooling oil duct and comprises a crank connecting rod mechanism, a heating mechanism, an oil inlet mechanism and an oil return mechanism;

the crank connecting rod mechanism is connected with the bottom of the piston and used for driving the piston to reciprocate up and down;

the heating mechanism is arranged at the top of the piston and used for heating the top of the piston;

the oil inlet mechanism is used for being connected with the bottom of the piston and used for injecting engine oil into the piston, and an oil inlet temperature sensor is arranged on an oil inlet pipeline of the oil inlet mechanism;

the oil return mechanism is used for being communicated with the inner cooling oil duct of the piston, the oil return mechanism is used for collecting engine oil flowing out of the inner cooling oil duct, and an oil return temperature sensor and a flowmeter are further arranged on an oil return pipeline of the oil return mechanism.

The detection device for the cooling efficiency of the cold oil duct in the piston comprises a crank connecting rod mechanism, a heating mechanism, an oil inlet mechanism and an oil return mechanism. The crank-connecting rod mechanism is used for providing power for the piston, converting the power of the motor into the up-and-down reciprocating motion of the piston, and simulating the up-and-down reciprocating motion of the piston in the actual use process to form the vibration cooling of engine oil in the inner cooling oil duct. The heating mechanism is used for intermittently heating the top of the piston, and when the piston reciprocates up and down under the drive of the crank connecting rod mechanism, the heating mechanism heats the top of the piston in a floating electromagnetic induction heating mode, so that the heating state of the piston in real work can be simulated. The oil inlet mechanism is used for conveying engine oil from the oil tank to spray the engine oil to the interior of the piston, the oil return mechanism is used for collecting the engine oil flowing out of the inner cooling oil duct and storing the engine oil into the oil tank of the base to form the circulating work of the oil inlet mechanism and the oil return mechanism, and the base is used for collecting and storing the engine oil and ensuring the oil temperature of the engine oil to be constant through the heater and the radiator.

In one possible implementation, the crank-link mechanism includes an electric motor, a crankshaft, a connecting rod, a bearing;

the motor is connected to one end of the crankshaft through the bearing, the connecting rod is connected to the crankshaft in the radial direction, and power of the motor is converted into vertical reciprocating motion of the connecting rod;

the other end of the connecting rod is connected with the bottom of the piston and drives the piston to reciprocate up and down.

In one possible implementation, the crank-link mechanism further includes: a guide rail;

the piston is at least connected with two sliding blocks, through holes are formed in the sliding blocks, and the sliding blocks penetrate through the through holes and are arranged on the guide rail.

In one possible implementation, the heating mechanism includes: the device comprises a heater, an insulating thermal baffle and a limiting sleeve;

the heater is arranged at the upper part of the piston, and the periphery of the heater is connected with the insulating heat-insulating plate;

the insulation heat insulation plate is provided with at least two limiting sleeves, through holes are formed in the limiting sleeves, and the limiting sleeves are arranged on the guide rails in a sliding mode.

In a possible embodiment, the heating mechanism further comprises a heat transfer module for being arranged between the piston and the heater;

the upper surface and the lower surface of the heat transfer module are respectively attached to the lower surface of the heater and the upper surface of the piston.

In a possible implementation mode, the heating mechanism further comprises at least one limiting block, the limiting block is arranged below the insulated heat insulation board, and when the limiting sleeve drives the heater to move downwards, the lower surface of the insulated heat insulation board abuts against the limiting block to stop moving.

In a possible implementation mode, a return spring is further arranged on the limiting sleeve, and the return spring is arranged on the guide rail in a penetrating mode and used for returning when the heater runs downwards.

In a possible implementation manner, the detection device further comprises a base, and an oil tank and a radiator are arranged on the base;

the oil tank is used for conveying and collecting the engine oil entering and exiting from the oil inlet mechanism and the oil return mechanism;

the radiator set up in around the oil tank, the oil tank bottom still is equipped with the heater.

The invention also provides a detection method of the cooling efficiency of the internal cooling oil duct of the piston, which is used for detecting the cooling effect of the internal cooling oil duct of the piston, and the method is detected by the detection device of the cooling efficiency of the internal cooling oil duct of the piston, and the method comprises the following steps:

a crank connecting rod mechanism is adopted to drive the piston to reciprocate up and down;

heating the top of the piston by a heating mechanism;

an oil inlet temperature sensor and an oil return temperature sensor are respectively arranged on the oil inlet pipeline and the oil return pipeline, and the temperature difference of engine oil entering and exiting the piston is measured;

a flowmeter is arranged on the oil return pipeline to detect the flow of the return oil;

the heat Q taken away by the engine oil from the inner cooling oil duct is obtained according to the following heat calculation formula by the engine oil temperature and the oil return flow: and Q is c m Δ t, c is the specific heat capacity of the engine oil, m is the return oil flow measured by the flowmeter, and Δ t is the temperature difference of the engine oil.

The invention provides a method for detecting the cooling efficiency of an inner cooling oil duct in a piston, which is used for detecting the cooling efficiency of the inner cooling oil duct on the top of the piston. The crank connecting rod mechanism is adopted to drive the piston to reciprocate up and down, the floating electromagnetic induction heating device is adopted to heat the top of the piston, and the real motion process and the heating process of the piston are simulated. An oil inlet temperature sensor and an oil return temperature sensor are respectively arranged on the oil inlet pipeline and the oil return pipeline, the temperature difference of engine oil entering and exiting the piston is measured, and a flowmeter is arranged on the oil return pipeline to detect the oil return flow. According to the measured engine oil temperature difference before and after the inner cooling oil duct absorbs heat and the engine oil flow taking heat away from the top of the piston, the heat quantity taken away by the engine oil from the inner cooling oil duct, namely the cooling efficiency of the inner cooling oil duct on the piston, can be calculated by adopting a heat quantity calculation formula.

The invention also provides an evaluation method of the cooling efficiency of the cooling oil duct in the piston, which is detected by the detection device of the cooling efficiency of the cooling oil duct in the piston, and the method comprises the following steps:

a crank connecting rod mechanism is adopted to drive the piston to reciprocate up and down;

heating the top of the piston by a heating mechanism;

installing temperature sensors on the piston top and the piston skirt, and measuring the temperature of the piston top and the piston skirt;

and evaluating the cooling effect of the inner cooling oil channel on the piston according to the difference value between the temperature of the top of the piston and the temperature of the skirt part of the piston.

The invention also provides an evaluation method of the cooling efficiency of the internal cooling oil duct of the piston, which adopts a crank connecting rod mechanism to drive the piston to reciprocate up and down, adopts a floating electromagnetic induction heating device to heat the top of the piston, and is used for simulating the real motion process and the heating process of the piston.

In addition to the technical problems, technical features constituting technical solutions, and advantages brought by the technical features of the technical solutions described above, other technical problems, other technical features included in the technical solutions, and advantages brought by the technical features that are solved by the detection device and the detection method for cooling efficiency of the cooling oil passage in the piston according to the embodiments of the present invention will be described in further detail in the detailed description.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a perspective view of a detection apparatus according to an embodiment of the present invention;

FIG. 2 is a front view of a detecting device according to an embodiment of the present invention;

FIG. 3 is a rear view of a testing device according to an embodiment of the present invention;

FIG. 4 is a top perspective view of a detection device according to an embodiment of the present invention;

FIG. 5 is a top plan view of a testing device according to an embodiment of the present invention;

FIG. 6 is a plan exploded view of a detection device according to an embodiment of the present invention;

fig. 7 is a perspective exploded view of a detection device according to an embodiment of the present invention;

fig. 8 is a schematic diagram of a detection method according to an embodiment of the present invention.

Description of reference numerals:

10: a detection device;

11: a base;

111: an oil tank;

112: a heat sink;

12: an oil inlet mechanism;

121: an electric oil pump;

122: an oil suction pipe;

123: an oil supply pipe;

124: a nozzle base;

125: cooling the nozzle;

126: an oil inlet temperature sensor;

13: an oil return mechanism;

131: an oil return pipe;

132: connecting an oil pipe;

133: an oil return temperature sensor;

134: a flow meter;

135: an oil drain pipe;

14: a crank link mechanism;

141: an electric motor;

142: a crankshaft;

143: a connecting rod;

144: a bearing;

145: a guide rail;

15: a heating mechanism;

151: a heater;

152: insulating and heat insulating boards;

153: a limiting sleeve;

154: a return spring;

155: a limiting block;

16: a piston;

161: a heat transfer module;

162: a slide block.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The piston is used as a core component on the engine, the top of the piston and an engine cylinder body are combined to form a combustion chamber, the combustion chamber is often in an environment of high-temperature combustion gas, so that the temperature of the top of the piston is high, in order to ensure the reliability of the use process of the piston, an inner cooling oil duct is often arranged in the piston, engine oil is sprayed into the inner cooling oil duct by a piston cooling nozzle, the engine oil is violently vibrated under the high-speed reciprocating motion of the piston, flows out from an oil duct outlet and takes away heat generated in the motion of the piston, and therefore the top of the piston is cooled. In the related art, in order to detect the cooling efficiency of the internal cooling oil duct on the piston, flowmeters are usually arranged in front of a piston cooling nozzle and at an oil return position of an internal cooling oil cavity of the piston, or a weighing mode is adopted, when the piston and the cooling nozzle are in static positions, the flow rates of engine oil when the piston enters and exits are measured, and the targeting efficiency of the piston cooling nozzle is obtained through the ratio of the oil quantity sprayed into the internal cooling oil duct of the piston by the piston cooling nozzle to the total oil quantity sprayed out by the piston cooling nozzle in unit time.

The inner cooling oil duct is called as a vibration oil cavity, the lubricating oil sprayed in the up-and-down motion of the piston splashes in the piston and collides, the lubricating oil is contacted with the inner wall of the piston through vibration to transfer the heat of the piston to the engine oil, if the piston is in a static state, most of the engine oil is on the lower half side of the piston, the upper half of the piston is heated, and the detection process is carried out in a normal temperature state and lacks a piston heating device.

In view of the above problems, the present invention provides a device and a method for detecting cooling efficiency of a cooling oil passage in a piston, which are used to solve the problem that in the prior art, the target efficiency of a cooling nozzle of the piston is detected and calculated to reflect the cooling effect of the piston, and the detection method can only measure the flow rate before and after the piston and cannot really obtain the cooling efficiency of the cooling oil passage to the piston. The following further describes the detection device and the detection method for the cooling efficiency of the cold oil passage in the piston according to the embodiment of the present invention.

The embodiment provides a device and a method for detecting the cooling efficiency of a cooling oil passage in a piston. Fig. 1 is a perspective view of a detection device according to an embodiment of the present invention, fig. 2 is a front view of the detection device according to the embodiment of the present invention, fig. 3 is a rear view of the detection device according to the embodiment of the present invention, fig. 4 is a perspective view of an upper portion of the detection device according to the embodiment of the present invention, fig. 5 is a plan view of the detection device according to the embodiment of the present invention, fig. 6 is a plan exploded view of the detection device according to the embodiment of the present invention, fig. 7 is a perspective exploded view of the detection device according to the embodiment of the present invention, and fig. 8 is a schematic view of a detection method according to the embodiment of the present invention.

Referring to fig. 1, a device 10 for detecting cooling efficiency of an internal cooling oil passage of a piston according to an embodiment of the present invention is provided, which is used for detecting the internal cooling oil passage of the piston 16. The detection device 10 comprises a heating mechanism 15, a crank link mechanism 14, an oil inlet mechanism 12 and an oil return mechanism 13. The heating mechanism 15 is arranged at the top of the piston 16 and used for heating the top of the piston 16; the crank connecting rod mechanism 14 is connected with the bottom of the piston 16 and used for driving the piston 16 to reciprocate up and down; the oil inlet mechanism 12 is arranged at the bottom of the piston 16, the oil inlet mechanism 12 is used for injecting engine oil into the piston 16, and an oil inlet temperature sensor 126 is arranged on an oil inlet pipeline of the oil inlet mechanism 12; the oil return mechanism 13 is communicated with the inner cooling oil channel of the piston 16, the oil return mechanism 13 is used for collecting engine oil flowing out of the inner cooling oil channel, and an oil return temperature sensor 133 and a flowmeter 134 are arranged on an oil return pipeline of the oil return mechanism 13.

Referring to fig. 2, the oil feed mechanism 12 is provided on one side of the bottom of the piston 16 for injecting oil into the interior of the piston 16. The oil inlet mechanism 12 is provided with an electric oil pump 121 as a power source, and pressurizes and conveys the engine oil in the oil tank 111 to the cooling nozzle 125 along an oil inlet pipeline, and the cooling nozzle 125 injects the engine oil into the piston 16 for cooling the interior of the piston 16.

The oil feed mechanism 12 may include: electric oil pump 121, oil inlet pipeline, cooling nozzle 125. The oil inlet pipeline can be divided into an oil suction pipe 122 and an oil supply pipe 123, one end of the oil suction pipe 122 is connected to the oil tank 111, the other end of the oil suction pipe 122 is connected to one end of the oil supply pipe 123 through an electric oil pump 121, and the electric oil pump 121 is disposed on the oil suction pipe 122 as a power source for pressurizing and delivering the oil to the piston 16.

The cooling nozzle 125 may be provided at the bottom thereof with a nozzle base 124, the other end of the oil supply pipe 123 is connected to the nozzle base 124, and the electric oil pump 121 serves as a power source to pressurize the oil in the oil tank 111, to supply the oil to the cooling nozzle 125 through the oil suction pipe 122, the oil supply pipe 123, and the internal oil passages of the nozzle base 124, and to spray the oil from the cooling nozzle 125 into the piston 16. An oil inlet temperature sensor 126 is arranged on an oil inlet pipeline of the oil inlet mechanism 12 and used for detecting the temperature of oil inlet, it should be noted that the oil inlet temperature sensor 126 may be arranged in the nozzle base 124, on the cooling nozzle 125, or on the oil suction pipe 122, and the specific position of the oil inlet temperature sensor 126 is not limited, and certainly, the closer the position of the oil inlet temperature sensor 126 is to the cooling nozzle 125, the more accurate the temperature before entering the piston 16 is detected, and the more accurate the cooling efficiency of the inner cooling oil passage on the piston 16 is detected by detecting the temperature of the engine oil entering and exiting the piston 16.

Referring to fig. 3, an oil return mechanism 13 is disposed on the other side of the bottom of the piston 16 and is communicated with the internal cooling oil passage of the piston 16 for collecting and storing the oil flowing out through the internal cooling oil passage of the piston 16. The piston 16 is used as a core component on an engine, the top of the piston 16 is often in an environment of high-temperature combustion gas, so that the temperature of the top of the piston 16 is high, in order to ensure the reliability of the use process of the piston 16, an inner cooling oil channel is often arranged inside the piston 16, engine oil is sprayed into the inner cooling oil channel through a cooling nozzle 125, the engine oil violently vibrates under the high-speed reciprocating motion of the piston 16, splashes in the piston 16 to generate collision motion, the engine oil contacts with the inner wall of the piston 16 through vibration to transfer the heat of the piston 16 to the engine oil, and the engine oil flows out from an outlet of the inner cooling oil channel and takes away the heat generated in the motion of the piston 16, so that the top of the piston 16 is cooled.

When the detection device 10 detects the cooling efficiency of the internal cooling oil channel of the piston 16, the piston 16 is in the up-and-down reciprocating motion, so that the oil return mechanism 13 and the piston 16 are mounted together to reciprocate together, the engine oil flows out from the outlet of the internal cooling oil channel, flows into the oil tank 111 through the oil return pipeline, and the engine oil flowing out from the internal cooling oil channel is completely collected in the oil tank 111. In this embodiment, the oil return line may include: oil return pipe 131, oil receiving pipe 132 and oil drain pipe 135.

In this embodiment, after the engine oil flows out through the outlet of the internal cooling oil passage, the engine oil may be collected through the oil return pipe 131, it should be noted that one end of the oil return pipe 131 is connected to the outlet of the internal cooling oil passage, so that the piston 16 and the oil return pipe 131 are mounted together to reciprocate together, the other end of the oil return pipe 131 is inserted into the oil receiving pipe 132, when the piston 16 drives the oil return pipe 131 to reciprocate up and down, the oil return pipe 131 reciprocates in the oil receiving pipe 132, and when the oil return pipe 131 and the piston 16 move to the top dead center, the lower end of the oil return pipe 131 still can extend into the oil receiving pipe 132, so as to ensure that the engine oil does not splash and can be completely collected in the oil receiving pipe 132 during the reciprocating motion of the piston 16.

It should be noted that, an oil return temperature sensor 133 and a flow meter 134 are further provided on the oil return line, and the oil return temperature sensor 133 is used to detect the temperature of the oil flowing out from the inner cooling oil passage, but it is needless to say that the closer the position of the oil return temperature sensor 133 is to the inner cooling oil passage of the piston 16, the more accurate the detection of the oil return temperature flowing out from the inner cooling oil passage is. The flow meter 134 disposed on the oil return line is used for detecting the flow rate of the engine oil injected into the top of the piston 16 by the cooling nozzle 125, when the engine oil is injected into the skirt portion of the piston 16 by the cooling nozzle 125, a part of the engine oil cannot be injected into the piston 16, and meanwhile, the direct cooling effect on the top of the piston 16 cannot be achieved, when the engine oil is injected into the piston 16, the engine oil flowing out from the inner cooling oil passage can only cool the top of the piston 16, that is, the flow rate of the engine oil flowing out from the inner cooling oil passage is the flow rate at which the heat can be taken away by the actual engine oil.

The flow meter 134 may be disposed on the lower line of the oil receiving pipe 132 for measuring the oil flow rate of the oil injected into the top of the piston 16 by the cooling nozzle 125, that is, the effective cooling flow rate of the oil to the inner cooling oil passage, and when the piston 16 reciprocates, the oil flowing out of the inner cooling oil passage flows into the flow meter 134 through the oil returning pipe 131 and the oil receiving pipe 132, so as to measure the oil flow rate of the oil taking heat away from the top of the piston 16. An oil drain pipe 135 may be provided between the flow meter 134 and the oil tank 111, and the oil drain pipe 135 is used to collect the oil tested in the flow meter 134 into the oil tank 111.

The oil return temperature sensor 133 is disposed on the oil return line and configured to detect a temperature of the engine oil flowing out from the inner cooling oil duct, and specifically, the oil return temperature sensor 133 may be disposed on the oil return pipe 131 of the oil return line, may be disposed on the oil receiving pipe 132, and may also be disposed on the oil drain pipe 135, where it should be noted that an installation position of the oil return temperature sensor 133 is not limited, and of course, the closer the installation position of the oil return temperature sensor 133 is to the inner cooling oil duct of the piston 16, the more accurately the oil return temperature flowing out from the inner cooling oil duct is detected.

With continued reference to fig. 2, the detecting device 10 is provided with a crank-link mechanism 14 for driving the piston 16 to reciprocate up and down, so as to simulate the up and down reciprocating motion of the piston 16 in actual operation, so as to form the oscillating cooling of the engine oil in the internal cooling oil passage, and when the motion state of the piston 16 is closer to actual, the measured cooling efficiency of the internal cooling oil passage is more accurate.

In the present embodiment, the crank mechanism 14 is disposed at the bottom of the piston 16, and may include: motor 141, crankshaft 142, connecting rod 143, and bearing 144. The motor 141 is coupled to one end of the crankshaft 142 through a bearing 144, and the bearing 144 provides a rotational support for the shaft for converting the power of the motor 141 into a rotational motion of the crankshaft 142. A connecting rod 143 is further disposed in the radial direction of the crankshaft 142, and the other end of the connecting rod 143 is in supporting connection with the bottom of the piston 16, that is, the crankshaft 142 rotates to drive the connecting rod 143 to reciprocate up and down under the driving of the motor 141, so as to drive the piston 16 to reciprocate up and down.

Therefore, the crank-connecting rod mechanism 14 is arranged on the detection device 10, so that the motor 141 drives the crankshaft 142 and the connecting rod 143 to move, the piston 16 can reciprocate up and down repeatedly under the driving of the connecting rod 143, the up-and-down reciprocating motion in the working process of the piston 16 and the oscillating cooling in the inner cooling oil channel can be simulated really, the actual working state of the piston 16 is restored really, and the cooling effect of the inner cooling oil channel detected by the detection device 10 is more accurate.

The crank linkage 14 may further include a guide rail 145, and the guide rail 145 is fixedly disposed on the detecting device 10. At least two sliding blocks 162 are arranged on the periphery of the piston 16, through holes are arranged on the sliding blocks 162, and the sliding blocks 162 penetrate through the guide rail 145 through the through holes arranged on the sliding blocks 162. During the up-and-down reciprocating motion of the piston 16 driven by the motor 141, the slider 162 passes through the guide rail 145 to reciprocate up and down under the driving of the piston 16, so as to provide a guiding function for the reciprocating motion of the piston 16. It should be noted that the motor 141 provided in this embodiment is an adjustable motor, and different rotation speeds can be set according to the test requirements.

In the present embodiment, the piston 16 can reciprocate up and down by the driving of the connecting rod 143, and moves up and down in a cycle along the direction of the guide rail 145 with the guide rail 145 as a guide. The periphery of the guide rail 145 can be provided with a protective frame, the upper part of the guide rail 145 can be installed and abutted against the protective frame to serve as a top dead center for the up-and-down movement of the slider 162, the height of the guide rail 145 is not limited, and the guide rail can be arranged according to actual detection requirements. Because the types of the pistons 16 are different and the matched sliding blocks 162 are different, when the cooling efficiency of the internal cooling oil passages of the pistons 16 of different specifications needs to be detected, only the sliding blocks 162 of the corresponding specifications need to be replaced, so that the detection device 10 can be generalized to achieve the purpose of saving the cost.

Referring to fig. 4 and 5, the heating mechanism 15 is used for simulating a heating state of a top portion of the piston 16, which is combined with the engine block to form a combustion chamber, in a high-temperature gas combustion environment, and the heating mechanism 15 includes: a heater 151, an insulating heat-insulating plate 152 and a limiting sleeve 153; the heater 151 is heated by electromagnetic induction, the heater 151 is arranged on the upper part of the piston 16, the periphery of the heater 151 is connected with the insulating and heat insulating plate 152, at least two limiting sleeves 153 are arranged on the insulating and heat insulating plate 152, through holes are formed in the limiting sleeves 153, and the limiting sleeves 153 are arranged on the guide rail 145 in a sliding mode, that is, the limiting sleeves 153 can move up and down in a reciprocating mode after penetrating through the guide rail 145.

Because the heater 151 is heated by electromagnetic induction, heat can be dissipated and transferred during operation, for the sake of safety and to ensure the accuracy of the detection result, the insulating board 152 disposed at the periphery of the heater 151 is made of an insulating material and can block a certain amount of heat, the insulating board 152 may be made of ceramic, glass, or other materials, and it should be noted that the specific material of the insulating board 152 is not limited. When the motor 141 drives the piston 16 to reciprocate up and down, the slider 162 on the piston 16 pushes the limiting sleeve 153 to drive the heater 151 to move up and down under the guidance of the guide rail 145.

Note that the heater 151 in this embodiment employs electromagnetic induction heating. Compared with open fire heating, electromagnetic induction heating has the following advantages: firstly, the heat quantity of electromagnetic induction heating is artificially controllable, the heat quantity can be kept in a stable and constant state, and the heat quantity received by the piston 16 tends to be in a stable state in the actual working process, so that the real heating process of the piston 16 can be simulated even if the heat source is constant; second, electromagnetic induction heating is safer relatively, simultaneously because the heat is controllable for 16 tops of pistons are heated more stably, evenly, and the data that the experiment was surveyed are also more accurate.

Since most of the piston 16 is made of aluminum, the electromagnetic heating effect is not good, in this embodiment, a heat transfer module 161 may be further disposed between the heater 151 and the piston 16, it should be noted that the heat transfer module 161 is made of ferromagnetic material, such as iron, cobalt, or others, and the specific material of the heat transfer module 161 is not limited.

The heat transfer module 161 is disposed on the upper portion of the piston 16 and is fixedly connected to the piston 16, and the connection manner is not limited. The upper surface of the heat transfer module 161 is attached to the heater 151, the lower surface of the heat transfer module 161 is in the same shape as the top of the piston 16, and the surfaces of the heat transfer module 161 are attached to each other, so that the heat transfer effect of the heater 151 to the piston 16 is better. Heater 151 during operation, the mode through electromagnetic induction can heat transfer module 161 earlier, heat transfer module 161 is heated the back and gives piston 16 top with heat transfer, because the heat of electromagnetic induction heating is artificial controllable, the heat can remain stable state, and the heating method is safer relatively, heat transfer module 161 through the setting can give piston 16 top with heater 151's heat transfer, make piston 16 top be heated more stably, even, the data that the experiment was surveyed are also more accurate.

Referring to fig. 6 and 7, the heater 151 is driven to move up and down along the guide rail 145 by a stopper sleeve 153 provided on the insulated board 152. In this embodiment, the heating mechanism 15 further includes at least one limiting block 155, the limiting block 155 is disposed below the insulated board 152, and when the limiting sleeve 153 drives the heater 151 to move downward, the lower surface of the insulated board 152 abuts against the limiting block 155 to stop the operation.

It should be noted that the limiting block 155 can be disposed on the base of the detection device 10 in a vertically sliding manner, or can be disposed on the protection frame of the detection device 10 in a sliding manner, and of course, the specific position of the limiting block 155 is not limited. For example, as shown in fig. 4 and 5, the limiting block 155 is disposed on the protection frame of the detection device 10 and can slide up and down. The upper surface of the limiting block 155 is the bottom dead center of the operation of the heater 151, that is, when the insulating board 152 drives the heater 151 to move up and down along the guide rail 145, the insulating board 152 contacts and interferes with the limiting block 155 when moving down to a certain position, so that the limiting block 155 can perform a limiting function.

In this embodiment, the limiting block 155 is adjustable up and down. Specifically, the height of the limiting block 155 can be adjusted according to the heating duration requirement of the piston 16, when the position of the limiting block 155 is higher, the heating duration of the piston 16 is shorter, and conversely, the position of the limiting block 155 is lower, the heating duration of the piston 16 is longer.

The up-down adjustable setting of the limiting block 155, that is, the heating mechanism 15 is floating heating, and can adopt periodic intermittent heating, and the heating mode has the following advantages: the oil-injection combustion process of the engine can be truly simulated, the oil-injection combustion process is carried out when the piston 16 rises to be close to the upper dead center, the heating is stopped when the piston runs downwards, and the temperature is also reduced when the piston runs to the lower dead center. This also has the advantage that the heating means is not integral with the piston 16, reducing the inertia of the reciprocating piston 16 during its reciprocating motion and reducing the stress on the system.

In this embodiment, a return spring 154 is further disposed on the upper portion of the limiting sleeve 153, and the return spring 154 is sleeved on the guide rail 145 for returning the heater 151 to the initial position when the heater 151 moves downward. When the motor 141 drives the piston 16 to move upwards from the bottom dead center, the sliding block 162 gradually contacts with the limiting sleeve 153, at this time, the high-frequency current in the heater 151 starts to heat the heat transfer module 161, the heat is stable and constant, the heat of the heat transfer module 161 is transferred to the top of the piston 16, the piston 16 continuously moves upwards under the driving of the motor 141, the sliding block 162 can push the limiting sleeve 153 to continuously move upwards, further push the heating mechanism 15 to move to the top dead center position, and at this time, the extrusion of the return spring 154 is the largest.

Under the driving of the motor 141, the crankshaft 142 rotates to drive the connecting rod 143 to reciprocate up and down, and further drive the piston 16 to reciprocate up and down, so that when the piston 16 pushes the heater 151 to move up to the top dead center, the piston 16 moves down under the driving of the connecting rod 143, and the return spring 154 is squeezed to drive the heating mechanism 15 to move down. When the insulated board 152 of the heating mechanism 15 abuts against the upper surface of the stopper 155, the heater 151 stops moving, the return spring 154 returns to the initial state, but the piston 16 is driven by the connecting rod 143 to move downward to the bottom dead center position, so that the heater 151 starts to be separated from the heat transfer module 161, and the piston 16 stops heating.

Along with the up-and-down reciprocating motion of the connecting rod 143, the piston 16 moves to the bottom dead center position under the driving of the connecting rod 143, and then moves upward from the bottom dead center position until the upper surface of the sliding block 162 starts to contact with the limiting sleeve 153, and at this stage, the piston 16 stops heating, and the temperature also slowly drops. When the sliding block 162 starts to push the limiting sleeve 153 to move upwards, the piston 16 starts to be subjected to heat transfer by the heat transfer module 161, and in cycles, the piston 16 reciprocates up and down and is subjected to intermittent heating by the heater 151. Therefore, the heating mechanism 15 adopts the floating electromagnetic induction heating, and can be used for simulating the heating state of the piston 16 in real work, and the cooling efficiency of the inner cooling oil duct obtained by testing is more accurate.

With continued reference to fig. 2, the detection mechanism may further include a base 11, and the base 11 is provided with an oil tank 111 and a radiator 112, where the oil tank 111 is used for storing and collecting the engine oil required in the experiment process, and specifically, the oil tank 111 is used for conveying and collecting the engine oil entering and exiting from the oil inlet mechanism 12 and the oil return mechanism 13. The radiator 112 is disposed around the oil tank 111, specifically, may be disposed around the oil tank 111, or may be disposed at the bottom or the upper portion of the oil tank 111, where the specific location is not limited, the radiator 112 is mainly used for radiating heat of engine oil in the oil tank 111, and when the temperature of the oil tank 111 is too high, the radiator 112 starts to operate.

The bottom of the oil tank 111 is further provided with a heater (not shown in the figure) for heating the engine oil in the oil tank 111, of course, the heater may be arranged at the bottom of the oil tank 111, or may be arranged at the periphery or the top of the oil tank 111, and when the heater is arranged at the bottom of the oil tank 111, the heating effect is better. Because the environmental temperature changes continuously along with the change of seasons, the temperatures of the oil in the oil tank 111 are different before and after the experiment, which causes the temperature of the oil in the oil tank to be too high or too low, and at this time, the heater and the radiator 112 work according to the change of the oil temperature, so as to constantly keep the oil temperature in the oil tank 111 constant.

The detection device 10 for the cooling efficiency of the cooling oil passage in the piston 16 provided by the embodiment comprises a crank link mechanism 14, a heating mechanism 15, an oil inlet mechanism 12 and an oil return mechanism 13. The crank-connecting rod mechanism 14 is used for providing power for the piston 16, converting the power of the motor 141 into the up-and-down reciprocating motion of the piston 16, and simulating the up-and-down reciprocating motion of the piston 16 in the actual use process so as to form the oscillation cooling of the engine oil in the internal cooling oil passage. The heating mechanism 15 is used for intermittently heating the top of the piston 16, and when the piston 16 is driven by the crank connecting rod mechanism 14 to reciprocate up and down, the heating mechanism 15 heats the top of the piston 16 in a floating electromagnetic induction heating mode, so that the heating state of the piston 16 in real work can be simulated. The oil inlet mechanism 12 is used for conveying engine oil from the oil tank 111 to spray the engine oil to the interior of the piston 16, the oil return mechanism 13 is used for collecting the engine oil flowing out of the internal cooling oil passage and collecting and storing the engine oil into the oil tank 111 of the base 11, and is used for forming the circulating work of the oil inlet mechanism 12 and the oil return mechanism 13, and the base 11 is used for collecting and storing the engine oil and ensuring the oil temperature of the engine oil to be constant through the heater and the radiator 112.

Referring to fig. 8, the embodiment of the present invention further provides a method for detecting the cooling efficiency of the internal cooling oil passage of the piston 16, which is used for detecting the cooling effect of the internal cooling oil passage of the piston 16, and the method is detected by the above-mentioned device 10 for detecting the cooling efficiency of the internal cooling oil passage of the piston 16. The specific method comprises the following steps: a crank connecting rod mechanism 14 is adopted to drive a piston 16 to reciprocate up and down; heating the top of the piston 16 by a heating mechanism 15; an oil inlet temperature sensor 126 and an oil return temperature sensor 133 are respectively arranged on the oil inlet pipeline and the oil return pipeline, and the temperature difference of the engine oil entering and exiting the piston 16 is measured; a flowmeter 134 is arranged on the oil return pipeline and used for detecting the oil return flow; and the heat taken away from the inner cooling oil channel is obtained according to the temperature difference of the engine oil and the return oil flow.

And S101, driving the piston 16 to reciprocate up and down by adopting the crank connecting rod mechanism 14. The detection device 10 is provided with a crank connecting rod mechanism 14 for converting the power of the motor 141 into the reciprocating motion of the piston 16, and for simulating the up-and-down reciprocating motion of the piston 16 in the actual use process, so as to form the oscillation cooling of the engine oil in the internal cooling oil passage. In addition, an oil inlet mechanism 12 and an oil return mechanism 13 are arranged on the detection device 10, the oil inlet mechanism 12 is used for conveying engine oil from the oil tank 111 to spray the engine oil to the interior of the piston 16, and the oil return mechanism 13 is used for collecting the engine oil flowing out of the internal cooling oil passage and collecting and storing the engine oil into the oil tank 111 so as to form the cycle work of the oil inlet mechanism 12 and the oil return mechanism 13.

And S102, heating the top of the piston 16 by using the heating mechanism 15. The heating mechanism 15 is arranged on the detection device 10, the heating mechanism 15 is floating electromagnetic induction heating, the heating is safer and controllable compared with open flame heating, the output heat is more stable, in addition, the heating mechanism 15 is periodic intermittent heating, the oil injection combustion process of the engine can be truly simulated, when the piston 16 rises to the position near the top dead center, the oil injection combustion is carried out, the heating is stopped when the piston runs downwards, and the temperature is also reduced when the piston runs to the bottom dead center.

The piston 16 reciprocates up and down under the driving of the crank link mechanism 14, when the piston moves to contact with the heating mechanism 15, the heater 151 adopts electromagnetic induction heating, and the heat transfer module 161 transfers heat to the piston 16 after being heated. During the up and down reciprocating motion of the piston 16, the heater 151 periodically contacts the heat transfer module 161 to transfer heat to the piston 16, thereby ensuring periodic intermittent heating of the top of the piston 16.

S103, an oil inlet temperature sensor 126 and an oil return temperature sensor 133 are respectively arranged on the oil inlet pipeline and the oil return pipeline, and the temperature difference of the engine oil entering and exiting the piston 16 is measured. Specifically, the oil inlet mechanism 12 is provided with an oil inlet temperature sensor 126 for detecting an oil inlet temperature, and it should be noted that the oil inlet temperature sensor 126 may be disposed in the nozzle base 124, on the cooling nozzle 125, or on the oil suction pipe 122, and a specific position of the oil inlet temperature sensor 126 is not limited, and of course, the closer the position of the oil inlet temperature sensor 126 is to the cooling nozzle 125, the more accurate the temperature before entering the piston 16 is detected, and the more accurate the cooling efficiency of the inner cooling oil passage on the piston 16 is detected by detecting the temperature of the engine oil entering and exiting the piston 16.

An oil return temperature sensor 133 is further arranged on the oil return pipeline, the oil return temperature sensor 133 is used for detecting the temperature of the engine oil flowing out of the inner cooling oil channel, the oil return temperature sensor 133 can be arranged on the oil return pipe 131 of the oil return pipeline, can be arranged on the oil receiving pipe 132, and can also be arranged on the oil drain pipe 135, the installation position of the oil return temperature sensor 133 is not limited, and certainly, the closer the position of the oil return temperature sensor 133 is to the inner cooling oil channel of the piston 16, the more accurate the oil return temperature flowing out of the inner cooling oil channel is detected.

And S104, arranging a flowmeter 134 on the oil return pipeline, and detecting the oil return flow. The heat taken away by the engine oil is calculated according to the temperature difference of the engine oil and the return oil flow meter 134. Specifically, the flow meter 134 is disposed on the oil return mechanism 13 and is configured to detect the flow rate of the engine oil injected into the top of the piston 16 by the cooling nozzle 125, when the engine oil is injected into the skirt portion of the piston 16 by the cooling nozzle 125, a part of the engine oil cannot be injected into the piston 16, and at the same time, the engine oil cannot be cooled, and when the engine oil is injected into the piston 16, the engine oil flowing out from the internal cooling oil passage can cool the top of the piston 16, that is, the flow rate of the engine oil flowing out from the internal cooling oil passage is the flow rate at which the heat can be taken away by the actual engine oil. When the piston 16 reciprocates, the oil flowing out of the inner cooling oil passage flows into the flow meter 134 through the oil return pipe 131 and the oil receiving pipe 132, so as to measure the oil flow rate which takes heat away from the top of the piston 16.

S105, obtaining the heat Q taken away by the engine oil from the internal cooling oil channel according to the following heat calculation formula by the engine oil temperature and the oil return flow: q is c m Δ t, c is the specific heat capacity of the engine oil, m is the return oil flow rate measured by the flow meter 134, and Δ t is the engine oil temperature difference. The temperature difference of the engine oil before and after entering the piston 16 and the oil return flow rate flowing out of the interior of the piston 16 can be obtained through the detection method, wherein the oil return flow rate is the engine oil flow rate of heat brought by the internal cooling oil passage passing through the piston 16. According to a heat calculation formula Q ═ c × m × Δ t, where Q is heat, c is specific heat capacity, m is fuel mass, and Δ t is temperature difference before and after heat absorption, the heat taken away by the engine oil from the internal cooling oil passage can be calculated, specifically, c in the formula is specific heat capacity of the engine oil, and m is mass of return oil flow rate, the flow meter 134 provided in the present embodiment may be a mass flow meter 134 or a volume flow meter 134, when the mass flow meter 134 is used, the mass of the return oil flow rate can be directly measured, when the volume flow meter 134 is used, the measured volume of the engine oil is multiplied by engine oil density to calculate the mass of the return oil flow rate, and Δ t in the formula is temperature difference before and after heat absorption of the engine oil, that is, the temperature difference measured by the oil inlet temperature sensor 126 and the return oil temperature sensor 133. The amount of heat taken away by the engine oil from the inner cooling oil passage, that is, the cooling efficiency of the inner cooling oil passage on the piston 16, can be calculated through the temperature, and the method can be used for detecting the cooling efficiency of the inner cooling oil passages of different pistons 16.

The method for detecting the cooling efficiency of the internal cooling oil passage in the piston 16 is provided by the embodiment and is used for detecting the cooling efficiency of the internal cooling oil passage on the top of the piston 16. The crank connecting rod mechanism 14 is adopted to drive the piston 16 to reciprocate up and down, the floating electromagnetic induction heating device is adopted to heat the top of the piston 16, and the real motion process and the heating process of the piston 16 are simulated. An oil inlet temperature sensor 126 and an oil return temperature sensor 133 are respectively arranged on the oil inlet pipeline and the oil return pipeline to measure the temperature difference of the engine oil entering and exiting the piston 16, and a flowmeter 134 is arranged on the oil return pipeline to detect the oil return flow. According to the measured engine oil temperature difference before and after the inner cooling oil passage absorbs heat and the engine oil flow rate taking heat away from the top of the piston 16, the heat quantity taken away by the engine oil from the inner cooling oil passage, namely the cooling efficiency of the inner cooling oil passage to the piston 16, can be calculated by adopting a heat quantity calculation formula.

The embodiment of the invention also provides a method for detecting the cooling efficiency of the cooling oil passage in the piston 16, which is detected by the device 10 for detecting the cooling efficiency of the cooling oil passage in the piston 16. The crank connecting rod mechanism 14 is adopted to drive the piston 16 to reciprocate up and down, the floating electromagnetic induction heating device is adopted to heat the top of the piston 16, on the basis of simulating the real motion process and the heating process of the piston 16, temperature sensors are respectively arranged on the top of the piston 16 and the skirt portion of the piston 16 and used for detecting the temperatures of the top of the piston 16 and the skirt portion of the piston 16, and the heat taken away by engine oil from the internal cooling oil duct is obtained according to the difference value between the temperatures of the top of the piston 16 and the skirt portion of the piston 16.

The temperature at the top of the piston 16 may also decrease as oil is injected into the piston 16 from the skirt of the piston 16 and exits the internal cooling gallery carrying heat away from the top of the piston 16. The heat quantity taken away by the engine oil from the internal cooling oil channel can be obtained by detecting the temperature difference between the top of the piston 16 and the skirt part of the piston 16, and the smaller the temperature difference between the top of the piston 16 and the skirt part of the piston 16, the better the cooling efficiency of the internal cooling oil channel on the piston 16 is, and conversely, the larger the temperature difference between the top of the piston 16 and the skirt part of the piston 16, the worse the cooling efficiency of the internal cooling oil channel on the piston 16 is. Of course, the method can only roughly judge the cooling efficiency of the inner cooling oil passage of the piston 16, and the cooling efficiency of the inner cooling oil passage of the piston 16 can be indirectly reflected by the temperature difference between the top of the piston 16 and the skirt of the piston 16. The trend of the cooling efficiency obtained by the method is consistent with that obtained by the first detection method, but the method only can roughly judge the cooling efficiency of the inner cooling oil passage of the piston 16, and the specific heat quantity taken away from the inner cooling oil passage is exactly calculated and can be obtained by the first detection method in the embodiment.

In the description of the present invention, it is to be understood that the terms "comprises", "comprising", "includes" and the like, when used, are to be construed as including the stated elements or components, but not excluding other elements or components.

In the description of the present invention, it is to be understood that the terms "center", "length", "width", "thickness", "top", "bottom", "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "inner", "outer", "axial", "circumferential", and the like, are used to indicate an orientation or positional relationship based on that shown in the drawings, merely to facilitate the description of the invention and to simplify the description, and do not indicate or imply that the position or element referred to must have a particular orientation, be of particular construction and operation, and thus, are not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integral; may be mechanically coupled, may be electrically coupled or may be in communication with each other; either directly or indirectly through intervening media, such as through internal communication or through an interaction between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.