Preheating control system and method for intake air of electrically controlled diesel engine for special vehicle

Abstract

This invention relates to an intake air preheating control system for electronically controlled diesel engines used in special vehicles, comprising an engine controller (ECU), a liquid heater, a battery, a liquid heater switch, a relay, and a grille heater. The invention also relates to a control method, comprising the steps of: acquiring coolant temperature, intake air temperature, and atmospheric pressure; calculating a weighted temperature and preheating time; comparing the weighted temperature with a coolant temperature threshold at the end of boiler heating; checking the liquid heater switch closure signal; determining whether the liquid heater should exit the heating process; allowing intake air preheating; setting the preheating time; performing intake air preheating; and ending preheating. This invention effectively improves the cold-start performance of electronically controlled diesel engines in low-temperature environments below -35°C and saves battery power.

Description

Technical Field

[0001] This invention relates to the field of electronic engine control technology, and more specifically to an intake air preheating control system and method for electronic diesel engines used in special vehicles. Background Technology

[0002] like Figures 1-2 As shown, when the existing electronically controlled diesel engine is cold-started in a low temperature environment of 0℃ to -35℃, the intake air temperature entering the combustion chamber is increased by controlling the grille preheater installed in the intake manifold to preheat for 10s to 45s during cold start, which can effectively improve the cold start performance of the diesel engine. However, when the ambient temperature is below -35℃, relying solely on intake grille heating, the cold start of the electronically controlled diesel engine becomes very difficult.

[0003] Some special vehicles have a minimum cold start requirement of -43°C. Before starting an electronically controlled diesel engine at low temperatures, a liquid heater (commonly known as a "boiler") is needed to heat the coolant in the engine cylinder block. It usually takes 20 to 30 minutes of heating to raise the coolant temperature to above 30°C, thereby increasing the temperature in the diesel engine combustion chamber and improving the combustibility of diesel fuel at low temperatures to meet the cold start requirements.

[0004] The shortcomings of existing technology are:

[0005] Because the temperature rise of the coolant in the boiler is very slow in low-temperature environments, the existing intake preheating control strategy cannot work in coordination with the boiler heating. As a result, the grille heater will complete the intake preheating in advance and cannot wait for the boiler to finish heating. On the other hand, if the power must be turned off and on again after the preparation is complete, the intake preheating will be restarted. Repeated preheating will waste the battery power. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a special vehicle electronically controlled diesel engine intake preheating control system and method, the purpose of which is to effectively improve the cold start performance of the electronically controlled diesel engine in low-temperature environments below -35℃ and save battery power.

[0007] To solve the above problems, the technical solution provided by the present invention is as follows:

[0008] A special vehicle electronically controlled diesel engine intake air preheating control system includes an engine controller (ECU), a liquid heater, a battery, a liquid heater switch, a first relay, a second relay, and a grille heater; wherein:

[0009] The two liquid heater switch control terminals of the engine controller ECU are electrically coupled to the two control signal input terminals of the liquid heater switch, respectively; the first relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the first relay; the second relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the second relay.

[0010] One end of the switch of the first relay is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the grid heater.

[0011] One end of the second relay switch is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the liquid heater.

[0012] The other end of the heating module of the liquid heater is connected to the negative terminal of the battery.

[0013] The other end of the heating module of the grille heater is grounded.

[0014] A method for controlling the intake air preheating of a special vehicle electronically controlled diesel engine, utilizing a special vehicle electronically controlled diesel engine intake air preheating control system, includes the following steps:

[0015] S100. Collect coolant temperature, intake air temperature, and atmospheric pressure; then calculate the weighted temperature and preheating time based on the coolant temperature, intake air temperature, and atmospheric pressure;

[0016] S200. Compare the weighted temperature with a pre-set threshold value for the coolant temperature at the end of boiler heating; then, based on the comparison result, perform the following operations:

[0017] If the weighted temperature is lower than the boiler heating end coolant temperature threshold, then execute S300;

[0018] If the weighted temperature is not lower than the boiler heating end coolant temperature threshold, then intake preheating is allowed, and the preheating time is set to the preheating duration; then S700 is executed.

[0019] S300. Within the manually preset power-on handshake waiting time, check whether the engine controller ECU has received the liquid heater switch closing signal; then, based on the check result, perform the following operations:

[0020] If the engine controller ECU receives the liquid heater switch closing signal during the power-on handshake waiting time, then execute S400;

[0021] If the engine controller ECU does not receive the liquid heater switch closing signal during the power-on handshake waiting time, intake air preheating is allowed, and the preheating time is set to the preheating duration; then S700 is executed.

[0022] S400. Preheating of intake air is prohibited; then the liquid heater starts heating; at the same time, the ECU starts timing, and the timing result is written to the boiler heating time in real time.

[0023] S500. Determine whether the liquid heater should exit the heating process; then, based on the determination result, perform the following operations:

[0024] If the determination result is that the liquid heater should exit the heating process, then execute S600;

[0025] If the determination result is that the liquid heater should not exit the heating process, then return and execute S400 again;

[0026] S600. Allows intake air preheating; sets the preheating time.

[0027] S700. Intake preheating begins, grille heater operates;

[0028] S800. Finish warm-up and then start the engine.

[0029] Preferably, the weighted temperature in S100 is expressed by the following formula:

[0030] T0 = ​​[k×T1 + (1-k)T2]

[0031] Where: T0 is the weighted temperature; k is a preset weighting coefficient, and k∈(0,1); T1 is the coolant temperature; T2 is the intake air temperature.

[0032] Preferably, the preheating time in S100 is expressed by the following formula:

[0033] t1 = f(T0, P)

[0034] Wherein: t1 is the preheating time, and the value of t1 is in the range of [0s, 60s]; P is the atmospheric pressure.

[0035] Preferably, determining whether the liquid heater should exit the heating process in step S500 specifically includes the following steps:

[0036] S510. Compare the value of the boiler heating time with a manually preset boiler heating end time threshold, and then perform the following operations based on the comparison result:

[0037] If the value of the boiler heating time is not lower than the boiler heating end time threshold, it is determined that the liquid heater should exit the heating process; then the current judgment process is exited.

[0038] If the value of the boiler heating time is lower than the boiler heating end time threshold, then execute S520;

[0039] S520. Compare the coolant temperature with a manually preset threshold for the coolant temperature at the end of boiler heating; then, based on the comparison result, perform the following operations:

[0040] If the coolant temperature is not lower than the boiler heating end coolant temperature threshold, then it is determined that the liquid heater should exit the heating process; then the current judgment process is exited.

[0041] If the coolant temperature is lower than the boiler heating end coolant temperature threshold, it is determined that the liquid heater should not exit the heating process; then the current judgment process is exited.

[0042] Preferably, setting the preheating time in S600 specifically includes the following steps:

[0043] S610. Compare the preheating time with the manually preset minimum preheating time; then, based on the comparison result, perform the following operations:

[0044] If the preheating time is greater than the minimum preheating time, then the preheating time is set to the preheating time.

[0045] If the preheating time is less than the minimum preheating time, then the preheating time is set to the minimum preheating time.

[0046] Preferably, the range of the power-on handshake waiting time is expressed by the following formula:

[0047] t on ∈[3s,10s]

[0048] Where: t on The power-on handshake waiting time.

[0049] Preferably, the range of the boiler heating end time threshold is expressed by the following formula:

[0050] t x ∈[10min, 30min]

[0051] Where: t x The threshold for the end time of boiler heating.

[0052] Preferably, the range of the boiler heating end cooling liquid temperature threshold is expressed by the following formula:

[0053] T max ∈[20℃, 30℃]

[0054] Wherein: T max The threshold temperature of the cooling liquid at the end of boiler heating.

[0055] Preferably, the range of the minimum preheating time is expressed by the following formula:

[0056] t0∈[30s,50s]

[0057] Where: t0 is the minimum preheating time.

[0058] Compared with the prior art, the present invention has the following advantages:

[0059] 1. Because the present invention achieves the coordinated heating operation of the engine intake grille heater and the liquid heater, it can effectively improve the cold start performance of the electronically controlled diesel engine in low temperature environments below -35℃;

[0060] 2. Since the intake preheating is only started after the present invention and other components are ready, there is no need for repeated preheating, thereby saving battery power. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the system structure of the prior art in the background section;

[0062] Figure 2 This is a schematic diagram of the method flow of the prior art in the background technology;

[0063] Figure 3 This is a schematic diagram of the system structure according to a specific embodiment of the present invention;

[0064] Figure 4 This is a schematic diagram of the method flow of a specific embodiment of the present invention;

[0065] Figure 5 A schematic diagram of the engine speed and intake preheating time during a cold start test at -41℃, as a specific embodiment of the present invention.

[0066] Figure 6 This is a schematic diagram of the coolant temperature and intake air temperature at -41℃ during a verification test of a specific embodiment of the present invention. Detailed Implementation

[0067] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0068] like Figure 3 As shown,

[0069] A special vehicle electronically controlled diesel engine intake preheating control system, characterized in that it comprises an engine controller (ECU), a liquid heater, a battery, a liquid heater switch, a first relay, a second relay, and a grille heater; wherein:

[0070] The two liquid heater switch control terminals of the engine controller ECU are electrically coupled to the two control signal input terminals of the liquid heater switch, respectively; the first relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the first relay; the second relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the second relay.

[0071] One end of the switch of the first relay is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the grid heater.

[0072] One end of the second relay switch is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the liquid heater.

[0073] The other end of the heating module of the liquid heater is connected to the negative terminal of the battery.

[0074] In this specific embodiment, the liquid heater is commonly referred to as a "boiler".

[0075] The other end of the heating module of the grille heater is grounded.

[0076] like Figure 4 As shown, a method for controlling the intake air preheating of a special vehicle electronically controlled diesel engine using a special vehicle electronically controlled diesel engine intake air preheating control system includes the following steps:

[0077] S100. Collect coolant temperature, intake air temperature, and atmospheric pressure; then calculate the weighted temperature and preheating time based on the coolant temperature, intake air temperature, and atmospheric pressure.

[0078] In this specific embodiment, the weighted temperature in S100 is expressed according to equation (1):

[0079] T0=k×T1+(1-k)T2 (1)

[0080] Where: T0 is the weighted temperature; k is a manually preset weighting coefficient, and k∈(0,1); T1 is the coolant temperature; T2 is the intake air temperature.

[0081] In this specific embodiment, the preheating time in S100 is expressed according to formula (2):

[0082] t1=f(T0,P) (2)

[0083] Where: t1 is the preheating time, and the value of t1 is in the range of [0s, 60s]; P is the atmospheric pressure.

[0084] S200. Compare the weighted temperature with the manually preset boiler heating end coolant temperature threshold; then perform the following operations based on the comparison result:

[0085] If the weighted temperature is lower than the boiler heating end coolant temperature threshold, i.e., T0 <T max If so, then S300 will be executed.

[0086] If the weighted temperature is not lower than the boiler heating end coolant temperature threshold, i.e., T0 ≥ T max If so, intake preheating is allowed, and the preheating time is set to preheating duration t1; then execute S700.

[0087] S300. During the manually preset power-on handshake waiting time t on Inside, check if the engine control unit (ECU) receives a signal indicating that the liquid heater switch is closed; then, based on the check results, perform the following operations:

[0088] If the power-on handshake waiting time t on Inside, when the engine controller ECU receives the liquid heater switch closing signal, it executes S400.

[0089] If the power-on handshake waiting time t on If the engine controller ECU does not receive a signal indicating that the liquid heater switch is closed, then intake air preheating is allowed, and the preheating time is set to preheating duration t1; then S700 is executed.

[0090] In this specific embodiment, the range of the power-on handshake waiting time is expressed by formula (3):

[0091] t on ∈[3s,10s] (3)

[0092] Where: t on This is the power-on handshake waiting time.

[0093] S400. Intake preheating is prohibited; then the liquid heater begins heating; simultaneously, the ECU starts timing, and the timing result is written to the boiler heating time t in real time. m .

[0094] It should be noted that in t m The intermediate coolant temperature T1 begins to rise.

[0095] S500. Determine whether the current liquid heater should exit the heating process; then, based on the determination result, perform the following operations:

[0096] If the determination result is that the current liquid heater should exit the heating process, then execute S600.

[0097] If the determination result is that the current liquid heater should not exit the heating process, then return and execute S400 again to continue boiler heating.

[0098] In this specific embodiment, determining whether the current liquid heater should exit the heating process in step S500 specifically includes the following steps:

[0099] S510. Compare the value of the boiler heating time with the manually preset boiler heating end time threshold, and then perform the following operations based on the comparison result:

[0100] If the value of the boiler heating time is not less than the boiler heating end time threshold, i.e., t m ≥t x If the current liquid heater fails to exit the heating process, then the current judgment process will be terminated.

[0101] If the value of the boiler heating time is lower than the boiler heating end time threshold, i.e., t m <t x If so, then S520 will be executed.

[0102] In this specific embodiment, the range of the boiler heating end time threshold is expressed by equation (4):

[0103] t x ∈[10min,30min] (4)

[0104] Where: t x This is the threshold for the end of boiler heating.

[0105] S520. Compare the coolant temperature with the manually preset coolant temperature threshold for the end of boiler heating; then, based on the comparison result, perform the following operations:

[0106] If the coolant temperature is not lower than the boiler heating end coolant temperature threshold, i.e., T1 ≥ T max If the current liquid heater fails to exit the heating process, then the current judgment process will be terminated.

[0107] If the coolant temperature is lower than the boiler heating end coolant temperature threshold, i.e., T1 < T max If the current liquid heater fails to exit the heating process, then the current judgment process will be terminated.

[0108] In this specific embodiment, the range of the cooling liquid temperature threshold after boiler heating is completed is expressed by formula (5):

[0109] T max ∈[20℃,30℃] (5)

[0110] Wherein: T max The threshold temperature for the cooling fluid at the end of boiler heating.

[0111] S600. Allows intake preheating; sets the preheating time.

[0112] In this specific embodiment, setting the preheating time in S600 specifically includes the following steps:

[0113] S610. Compare the preheating time t1 with the manually preset minimum preheating time; then perform the following operations based on the comparison results:

[0114] If the preheating time is longer than the minimum preheating time, then the preheating time will be set to the preheating duration.

[0115] If the preheating time is less than the minimum preheating time, then the preheating time will be set to the minimum preheating time.

[0116] It should be noted that the preheating time setting logic is MAX(t0,t1).

[0117] In this specific embodiment, the range of the minimum preheating time is expressed by equation (6):

[0118] t0∈[30s,50s] (6)

[0119] Where: t0 is the minimum preheating time.

[0120] S700. Intake preheating begins, grille heater starts working.

[0121] S800. Finish warm-up and then start the engine.

[0122] To further verify and demonstrate the technical effects of the present invention, this specific embodiment also provides a cold start test of an electronically controlled diesel engine at a low temperature of -41℃ using the method of the present invention. The results are as follows: Figures 5-6 As shown.

[0123] from Figures 5-6 From the curve, we can clearly and intuitively see that the method of the present invention can effectively improve the low-temperature cold start performance of the electronically controlled diesel engine.

[0124] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than those set forth in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the disclosed individual embodiments. Therefore, the appended claims are hereby clearly incorporated into the detailed description, wherein each claim stands alone as a preferred embodiment of the invention.

[0125] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0126] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is interpreted in a manner similar to the term "including," as interpreted when used as a conjunction in the claims. Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0127] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for controlling the intake air preheating of a special vehicle electronically controlled diesel engine, characterized in that: A special vehicle electronically controlled diesel engine intake air preheating control system is utilized; the special vehicle electronically controlled diesel engine intake air preheating control system includes an engine controller ECU, a liquid heater, a battery, a liquid heater switch, a first relay, a second relay, and a grille heater; wherein: The two liquid heater switch control terminals of the engine controller ECU are electrically coupled to the two control signal input terminals of the liquid heater switch, respectively; the first relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the first relay; the second relay control terminal of the engine controller ECU is electrically coupled to the control signal input terminal of the second relay. One end of the switch of the first relay is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the grid heater. One end of the second relay switch is connected to the positive terminal of the battery, and the other end is connected to one end of the heating module of the liquid heater. The other end of the heating module of the liquid heater is connected to the negative terminal of the battery. The other end of the heating module of the grille heater is grounded; The method for controlling the intake air preheating of a special vehicle electronically controlled diesel engine includes the following steps: S100. Collect the coolant temperature, intake air temperature, and atmospheric pressure; then calculate the weighted temperature and preheating time based on the coolant temperature, intake air temperature, and atmospheric pressure; S200. Compare the weighted temperature with a pre-set threshold value for the coolant temperature at the end of boiler heating; then, based on the comparison result, perform the following operations: If the weighted temperature is lower than the boiler heating end coolant temperature threshold, then execute S300; If the weighted temperature is not lower than the boiler heating end coolant temperature threshold, then intake preheating is allowed, and the preheating time is set to the preheating duration; then S700 is executed. S300. Within the manually preset power-on handshake waiting time, check whether the engine controller ECU has received the liquid heater switch closing signal; then, based on the check result, perform the following operations: If the engine controller ECU receives the liquid heater switch closing signal during the power-on handshake waiting time, then execute S400; If the engine controller ECU does not receive the liquid heater switch closing signal during the power-on handshake waiting time, intake air preheating is allowed, and the preheating time is set to the preheating duration; then S700 is executed. S400. Preheating of the intake air is prohibited; then the liquid heater starts heating; at the same time, the ECU starts timing, and the timing result is written to the boiler heating time in real time; S500. Determine whether the liquid heater should exit the heating process; then, based on the determination result, perform the following operations: If the determination result is that the liquid heater should exit the heating process, then execute S600; If the determination result is that the liquid heater should not exit the heating process, then return and execute S400 again; S600. Allows intake preheating; sets the preheating time; S700. Intake preheating begins, grille heater operates; S800. End the warm-up, then start the engine.

2. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 1, characterized in that: The weighted temperature described in S100 is expressed by the following formula: in: The weighted temperature; These are manually preset weighting coefficients, and ; The temperature of the coolant; The intake air temperature is [value missing].

3. The intake preheating control method for a special vehicle electronically controlled diesel engine according to claim 2, characterized in that: The preheating time described in S100 is expressed by the following formula: in: The preheating time is, and The range of values ​​is ; The atmospheric pressure is [value].

4. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 3, characterized in that: S500 determines whether the liquid heater should exit the heating process, specifically including the following steps: S510. Compare the value of the boiler heating time with a manually preset boiler heating end time threshold, and then perform the following operations based on the comparison result: If the value of the boiler heating time is not lower than the boiler heating end time threshold, it is determined that the liquid heater should exit the heating process; then the current judgment process is exited. If the value of the boiler heating time is lower than the boiler heating end time threshold, then execute S520; S520. Compare the coolant temperature with a manually preset threshold for the coolant temperature at the end of boiler heating; then, based on the comparison result, perform the following operations: If the coolant temperature is not lower than the boiler heating end coolant temperature threshold, then it is determined that the liquid heater should exit the heating process; then the current judgment process is exited. If the coolant temperature is lower than the boiler heating end coolant temperature threshold, it is determined that the liquid heater should not exit the heating process; then the current judgment process is exited.

5. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 4, characterized in that: Setting the preheating time in S600 specifically includes the following steps: S610. Compare the preheating time with the manually preset minimum preheating time; then, based on the comparison result, perform the following operations: If the preheating time is greater than the minimum preheating time, then the preheating time is set to the preheating time. If the preheating time is less than the minimum preheating time, then the preheating time is set to the minimum preheating time.

6. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 5, characterized in that: The range of values ​​for the power-on handshake waiting time is expressed by the following formula: in: The power-on handshake waiting time.

7. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 6, characterized in that: The range of the boiler heating end time threshold is expressed by the following formula: in: The threshold for the end time of boiler heating.

8. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 7, characterized in that: The range of the boiler heating end cooling liquid temperature threshold value is expressed by the following formula: in: The threshold temperature of the cooling liquid at the end of boiler heating.

9. The intake air preheating control method for a special vehicle electronically controlled diesel engine according to claim 8, characterized in that: The range of the minimum preheating time is expressed by the following formula: in: This refers to the minimum preheating time.

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