Method and system for adjusting temperature of plateau low-temperature environment bin under strong transient working condition of engine

Abstract

The invention discloses a method and system for adjusting the temperature of a plateau low-temperature environment bin under the strong transient working condition of an engine, and relates to the technical field of engine bench test low-temperature bin control. The system comprises an active regulation module, a passive regulation module and an altitude correction module of the comprehensive regulation system for the temperature in the low-temperature cabin of the engine; the heat radiation to the environment is estimated through the energy conversion efficiency of the actual operation condition of the engine, that is, the engine power change rate is taken as the reference, the influence of the altitude on the heat efficiency of the engine and a feedback system of the temperature in the bin are combined, the temperature in the bin is adjusted in real time, and high-stability control over the temperature in the bin under the strong transient condition is obtained. Based on the energy conversion of the actual operation condition of the engine, the influence of the altitude on the heat efficiency of the engine is considered, and the stable control of the temperature in the low-temperature bin under the strong transient condition of the engine can be realized by combining a feedback mechanism in the bin.

Description

Technical Field

[0001] The present invention relates to an engine environment chamber, and in particular to a temperature regulation method and system for a plateau low-temperature environment chamber under a strong transient engine operating condition. Background Art

[0002] With the special environmental demands of national defense construction, the application of power equipment and equipment in high-altitude, cold environments requires high reliability and stability, which is essential for strong border defense. Therefore, the development of high-altitude, cold-weather performance for power equipment is particularly important. The high-altitude, cold-weather chamber can meet the requirements for engine performance development in extreme conditions such as high altitudes (0-5000m) and temperatures of -50-60°C. A heat exchanger provides ventilation within the chamber for real-time temperature control. During steady-state engine operation, the chamber can maintain a temperature control within ±5°C, meeting the ambient temperature requirements for engine performance development. However, under severe transient engine conditions, the deviation between the actual chamber temperature and the preset temperature can increase significantly. A feedback control system is implemented within the chamber, but the engine's outward heat radiation always precedes the feedback signal, causing the feedback signal to be prolonged and increased. This can cause a sudden change in the chamber temperature during the next low-heat radiation event. Therefore, under severe transient engine conditions, the chamber temperature control must adapt to the engine operating conditions to address overheating or underheating.

[0003] At present, the temperature inside the warehouse is often monitored by the warehouse temperature sensor and fed back to the temperature control terminal. The control terminal issues temperature adjustment instructions after calculation. This method can meet the needs of stable heat source, stable heat dissipation and heating, but it is not suitable for stable control of the temperature inside the warehouse with strong transient heat source (the engine frequently changes its operating conditions). Summary of the Invention

[0004] The present invention aims to provide a method and system for regulating the temperature of a cabin in a high-altitude, low-temperature environment under severe engine transient conditions. The system comprises an active regulation module, a passive regulation module, an altitude correction module, and a temperature regulation module. The active regulation module, the passive regulation module, and the altitude correction module are all independent and do not interfere with each other. Based on the power conversion of the actual engine operating conditions, combined with the effect of altitude on engine thermal efficiency and the in-cabin feedback system, the present invention can achieve in-cabin temperature control under severe engine transient conditions.

[0005] The technical solution of the present invention is:

[0006] A method for regulating temperature in a high-altitude low-temperature environment chamber under a strong transient engine operating condition, comprising:

[0007] (1) Active regulation

[0008] The engine's actual operating conditions are used as a trigger mechanism to calculate the engine's power output and the engine power adjustment coefficient for adjacent operating conditions. The air flow rate is adjusted based on this coefficient:

[0009]

[0010] Where: n i is the instantaneous engine speed; T tq,i is the instantaneous torque of the engine; p i is the instantaneous power of the engine; α i is the engine power adjustment coefficient; i is a natural number; air flow rate is the air mass per unit time, kg / h;

[0011] (2) Passive regulation

[0012] The air flow rate is adjusted in real time based on the temperature feedback from the temperature sensor in the low-temperature chamber, and the ratio of the actual temperature to the expected temperature is used as the temperature adjustment factor, including:

[0013]

[0014] λ i is the temperature adjustment factor of the low-temperature chamber;

[0015] (3) Altitude correction

[0016] Determine the thermal efficiency as a function of altitude using random steady-state conditions, including:

[0017] η h =η0+a·h 2 +b·h (4)

[0018] Where η0 is the thermal efficiency when h = 0m, h is the altitude, a and b are constants, and η h is the thermal efficiency at altitude h;

[0019] When the engine thermal efficiency increases or decreases, the engine's external heat radiation will change accordingly. The derivative of formula (4) is used as the altitude correction coefficient τ of the air flow rate at the inlet and outlet of the low-temperature warehouse. h =2a·h+b.

[0020] Furthermore, according to the actual operating conditions of the engine, the real-time air flow rate adjustment coefficient of the low-temperature chamber includes:

[0021] Coefficient α i ,λ i and τ h Independent of each other, the final low-temperature chamber real-time air flow rate adjustment coefficient δ i :

[0022] δ i =αi ·λ i ·τ h .

[0023] Furthermore, the real-time air flow rate v i for:

[0024] v i =v i-1 ·δ i

[0025] Among them, v0 is the reference air flow rate, and i is a natural number.

[0026] Furthermore, determining the functional relationship between thermal efficiency and altitude through random steady-state operating conditions includes:

[0027] Taking 500m as an altitude point and full throttle at rated speed as the test condition, thermal efficiency tests were carried out at altitudes of 0-5000m. Then, data fitting was performed to obtain a mathematical model of thermal efficiency and altitude.

[0028] A temperature control system for a high-altitude low-temperature environment chamber under strong transient engine operating conditions includes an active control module, a passive control module, an altitude correction module, and a temperature control module, wherein:

[0029] 1. Active adjustment module

[0030] The engine's actual operating conditions are used as a trigger mechanism to calculate the engine's power output and the engine power adjustment coefficient for adjacent operating conditions. The air flow rate is adjusted based on this coefficient:

[0031]

[0032] n i is the instantaneous engine speed, r / min; T tq,i is the instantaneous torque of the engine, Nm; p i is the instantaneous power of the engine, kW; α i is the engine power adjustment coefficient; i is a natural number.

[0033] 2. Passive adjustment module

[0034] The air flow rate is adjusted in real time based on the temperature feedback from the temperature sensor in the low-temperature chamber, and the ratio of the actual temperature to the expected temperature is used as the temperature adjustment factor, including:

[0035]

[0036] Among them, λ i is the temperature adjustment factor of the low-temperature chamber.

[0037] 3. Altitude correction module

[0038] Because altitude only affects the engine's combustion process, which converts chemical energy into thermal energy, thermal efficiency is the primary indicator for evaluating engine thermal conversion. It's necessary to determine how the engine's thermal efficiency changes at different altitudes. This can be done through random steady-state operating conditions to determine the functional relationship between thermal efficiency and altitude. For example, using 500m as an altitude point and full throttle at rated speed as the test condition, thermal efficiency tests are conducted at altitudes of 0-5000m. Data fitting is then performed to obtain a mathematical model for the relationship between thermal efficiency and altitude. This includes:

[0039] η h =η0+a·h 2 +b·h

[0040] η0 is the thermal efficiency when h = 0m; h is the altitude, m; a, b are constants; η h is the thermal efficiency at altitude h.

[0041] When the engine thermal efficiency increases or decreases, the engine's external heat radiation will change accordingly. The above formula is derived and the derivative is used as the altitude correction coefficient for the inlet and outlet air flow rate of the low-temperature chamber:

[0042] τ h =2a·h+b

[0043] τ h The altitude correction coefficient for the inlet and outlet air velocity of the cryogenic chamber at altitude h. The recommended value is 1.

[0044] 4. Temperature regulation module:

[0045] The above three coefficients (α i ;λ i ; τ h ) are independent of each other and are processed by the multiplication principle to obtain the final low-temperature warehouse real-time air flow rate adjustment coefficient δ i

[0046] δ i =α i ·λ i ·τ h

[0047] v i =v i-1 ·δ i

[0048] v0 is the reference air flow rate (design value, related to the capacity of the low-temperature chamber), kg / h; v i is the real-time air flow rate, kg / h.

[0049] A computer-readable storage medium having a computer program stored thereon, characterized in that the computer program can be executed by a processor to implement the steps of a method for controlling the temperature of a high-altitude low-temperature environment chamber under a strong transient engine operating condition described in the present invention.

[0050] The beneficial effects of the present invention include:

[0051] The present invention realizes real-time regulation of the temperature inside the low-temperature warehouse of the engine through an active regulation module, a passive regulation module and an altitude correction module. The active regulation module obtains the power coefficient based on the energy conversion of the actual operating conditions of the engine; the passive regulation module obtains the target temperature regulation factor based on the monitoring value of the temperature sensor inside the warehouse; the altitude correction module obtains the altitude correction factor based on the influence of altitude on the thermal efficiency of the engine; the real-time air flow rate regulation coefficient of the temperature inside the low-temperature warehouse of the engine is the product of the power adjustment coefficient, the temperature adjustment factor and the altitude correction coefficient. Compared with the prior art, which only sets a feedback regulation system to adjust the temperature and is not suitable for the temperature control inside the engine under strong transient conditions, the present application is based on the energy conversion of the actual operating conditions of the engine, while taking into account the influence of altitude on the thermal efficiency of the engine, and combined with the feedback mechanism inside the warehouse, it can achieve stable control of the temperature inside the low-temperature warehouse under strong transient conditions of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The present invention is a flow chart of a method for regulating the temperature of a high-altitude low-temperature environment chamber under a strong transient engine operating condition. DETAILED DESCRIPTION

[0053] A temperature control system for a high-altitude low-temperature environment chamber under strong transient engine operating conditions includes an active control module, a passive control module, an altitude correction module and a temperature control module. The active control module, the passive control module, the altitude correction unit, etc. are independent of each other and do not interfere with each other.

[0054] 1. Active adjustment module

[0055] The engine's actual operating conditions are used as a trigger mechanism to calculate the engine's power output and the engine power adjustment coefficient for adjacent operating conditions. The air flow rate is adjusted based on this coefficient:

[0056]

[0057] n i is the instantaneous engine speed, r / min; T tq,i is the instantaneous torque of the engine, Nm; p i is the instantaneous power of the engine, kW; α i is the engine power adjustment coefficient; i is a natural number.

[0058] 2. Passive adjustment module

[0059] The air flow rate is adjusted in real time based on the temperature feedback from the temperature sensor in the low-temperature chamber, and the ratio of the actual temperature to the expected temperature is used as the temperature adjustment factor, including:

[0060]

[0061] λ i is the temperature adjustment factor of the low temperature chamber

[0062] 3. Altitude correction module

[0063] Because altitude only affects the engine's combustion process, which converts chemical energy into thermal energy, thermal efficiency is the primary indicator for evaluating engine thermal conversion. It's necessary to determine how the engine's thermal efficiency changes at different altitudes. This can be done through random steady-state operating conditions to determine the functional relationship between thermal efficiency and altitude. For example, using 500m as an altitude point and full throttle at rated speed as the test condition, thermal efficiency tests are conducted at altitudes of 0-5000m. Data fitting is then performed to obtain a mathematical model for the relationship between thermal efficiency and altitude. This includes:

[0064] η h =η0+a·h 2 +b·h

[0065] η0 is the thermal efficiency when h = 0m; h is the altitude, m; a, b are constants; η h is the thermal efficiency at altitude h.

[0066] When the engine thermal efficiency increases or decreases, the engine's external heat radiation will change accordingly. The above formula is derived and the derivative is used as the altitude correction coefficient for the inlet and outlet air flow rate of the low-temperature chamber:

[0067] τ h =2a·h+b

[0068] τ h The altitude correction coefficient for the air flow rate at the inlet and outlet of the cryogenic warehouse at an altitude of h.

[0069] 4. Temperature regulation module: the above three coefficients (α i ;λ i ; τ h ) are independent of each other and are processed by the multiplication principle to obtain the final low-temperature warehouse real-time air flow rate adjustment coefficient δ i

[0070] δ i =α i ·λ i ·τ h

[0071] v i =v i-1 ·δi

[0072] v0 is the reference air flow rate (design value, related to the capacity of the low-temperature chamber), kg / h; v i is the real-time air flow rate, kg / h.

[0073] Example

[0074] Assume that the target control temperature of the cryogenic chamber is -10°C, the current actual temperature is -7°C, the current cryogenic chamber air flow rate is 30kg / h, the engine power is 80kW, and the next operating condition is 90kW. Based on each control module, the following can be calculated:

[0075] Active control engine power adjustment coefficient α=90 / 80=1.125

[0076] Passively controlled temperature regulation factor

[0077] The altitude correction coefficient adopts the recommended value τ h =1

[0078] Then, the real-time air flow rate adjustment coefficient δ of the low-temperature chamber is i =1.125×1.43×1=1.61

[0079] Therefore, the next air flow rate of the low temperature chamber is 1.61×30=48.3 kg / h.

Claims

1. A method for regulating the temperature of a high-altitude low-temperature environment chamber under a strong transient engine operating condition, characterized in that: The method includes: (1) Active regulation The engine's actual operating conditions are used as a trigger mechanism to calculate the engine's power output and the engine power adjustment coefficient for adjacent operating conditions. The air flow rate is adjusted based on this coefficient: n i is the instantaneous engine speed; T tq,i is the instantaneous torque of the engine; p i is the instantaneous power of the engine; α i is the engine power adjustment coefficient; i is a natural number; (2) Passive regulation The air flow rate is adjusted in real time based on the temperature feedback from the temperature sensor in the low-temperature chamber. temp实际,i With the expected temperature T temp预期,i The ratio of is used as the temperature adjustment factor λ i : (3) Altitude correction Determine the thermal efficiency as a function of altitude using random steady-state conditions, including: or h =η0+a·h 2 +b·h (4) Where η0 is the thermal efficiency when h = 0m, h is the altitude, a and b are constants, and η h is the thermal efficiency at altitude h; When the engine thermal efficiency increases or decreases, the engine's external heat radiation will change accordingly. The derivative of formula (4) is used as the altitude correction coefficient τ of the air flow rate at the inlet and outlet of the low-temperature warehouse. h =2a·h+b; Coefficient α i ,λ i and τ h Independent of each other, the final low-temperature chamber real-time air flow rate adjustment coefficient δ i : d i =a i ·l i ·t h Real-time air flow rate in low temperature chamber v i for: v i =v i-1 ·δ i Among them, v0 is the reference air flow rate, and i is a natural number.

2. The method according to claim 1, characterized in that The functional relationship between thermal efficiency and altitude determined by random steady-state operating conditions includes: Taking 500m as an altitude point and full throttle at rated speed as the test condition, thermal efficiency tests were carried out at altitudes of 0-5000m. Then, data fitting was performed to obtain a mathematical model of thermal efficiency and altitude.

3. The method according to claim 1, characterized in that Altitude correction factor τ h =1.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program can be executed by a processor to implement the steps of a method for regulating the temperature of a high-altitude low-temperature environment chamber under a strong transient engine operating condition as described in any one of claims 1 to 3.

5. A temperature control system for a high-altitude low-temperature environment chamber under strong transient engine operating conditions, characterized in that: The system includes: An active adjustment module, configured to implement the steps of the active adjustment portion of the method for adjusting the temperature of a high-altitude low-temperature environment chamber under a strong transient engine operating condition as described in any one of claims 1 to 3; A passive adjustment module, configured to implement the passive adjustment steps of the temperature adjustment method for a high-altitude low-temperature environment chamber under a strong transient engine operating condition as described in any one of claims 1 to 3; An altitude correction module, configured to implement the altitude correction step of the temperature adjustment method for a high-altitude low-temperature environment chamber under a strong transient engine operating condition as described in any one of claims 1 to 3; Temperature control module: The product of the altitude correction coefficient, engine power adjustment coefficient, and temperature adjustment factor is used as the real-time air flow rate adjustment coefficient. The current air flow rate is multiplied by the real-time air flow rate adjustment coefficient to obtain the air flow rate required for the next temperature control, and temperature control is achieved with this air flow rate.

6. The system according to claim 5, characterized in that The active adjustment module, the passive adjustment module, and the altitude correction module are all independent of each other.

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