An over-temperature protection structure for a cylinder head

Abstract

The present invention relates to the technical field of engines, and particularly to an over-temperature protection structure for a cylinder head, which includes a cylinder head, an exhaust passage, and a cooling water jacket. The exhaust passage includes an upper exhaust passage and a lower exhaust passage, which are respectively arranged in the middle and below the front wall of the cylinder head and communicate with the inner cavity of the cylinder head. Cooling water jackets are provided on both sides of the cylinder head, and a metal temperature sensor hole is provided between the cooling water jacket and the lower exhaust passage, and a cylinder head metal temperature sensor is fixed in the metal temperature sensor hole. By designing a special temperature sensor in the water jacket on the exhaust side of the cylinder head, the present invention detects the metal temperature on the exhaust side of the cylinder head and monitors the operation of the cylinder head, ensures that the cylinder head operates within a reasonable temperature range, guarantees the operation reliability of the engine and the cylinder head, and avoids over-temperature damage to the engine and the cylinder head.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly to an over-temperature protection structure for a cylinder head. Background Art

[0002] During the normal operation of an engine, the thermal energy generated by the combustion of fossil fuels is converted into mechanical energy to drive the engine to run at high speed. In this process, the interior of the engine needs to withstand the erosion of high-temperature combustion gases from the combustion of fossil fuels and the high mechanical loads generated by the combustion explosion pressure. The cylinder head is a main component of the engine and simultaneously bears the high thermal load of combustion and the high mechanical load of explosion pressure. Therefore, in the design of the cylinder head, a special cooling water jacket is often designed for cooling to ensure that the operating temperature of the cylinder head is within the allowable range of the material.

[0003] As an important component of the engine, once the cylinder head is damaged, it will cause serious failures such as the scrapping of the engine. To avoid the damage of the cylinder head caused by the failure of the cooling system and the resulting loss of the entire engine, an over-temperature protection structure and strategy for the cylinder head have been designed and developed, which can effectively avoid the serious failures of the cylinder head and the engine even when the cooling system fails.

[0004] Based on the above considerations, the present invention designs an over-temperature protection structure for a cylinder head. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an over-temperature protection structure for a cylinder head. By designing a special temperature sensor in the water jacket on the exhaust side of the cylinder head, the metal temperature on the exhaust side of the cylinder head is detected to monitor the operating condition of the cylinder head; ensuring that the cylinder head operates within a reasonable temperature range, guaranteeing the operating reliability of the engine and the cylinder head, and avoiding over-temperature damage to the engine and the cylinder head.

[0006] To achieve the purpose of the present invention, the technical solution adopted by the present invention is as follows:

[0007] The present invention discloses an over-temperature protection structure for a cylinder head, including a cylinder head, an exhaust passage, and a cooling water jacket. The exhaust passage includes an upper exhaust passage and a lower exhaust passage, which are respectively arranged in the middle and below the front wall of the cylinder head and communicate with the inner cavity of the cylinder head. Cooling water jackets are provided on both sides of the cylinder head. A metal temperature sensor hole is provided between the cooling water jacket and the lower exhaust passage, and a cylinder head metal temperature sensor is fixed in the metal temperature sensor hole.

[0008] The metal temperature sensor hole is inclined, and its closed end is located in the high-temperature area below the upper exhaust passage, and its open end obliquely penetrates downward through the outer wall of the cylinder head.

[0009] The closed end of the metal temperature sensor hole is located between the upper exhaust passage and the lower exhaust passage.

[0010] The distance between the closed end of the metal temperature sensor hole and the upper exhaust passage and the lower exhaust passage is equal.

[0011] The metal temperature sensor of the cylinder head is electrically connected to the ECU for transmitting metal temperature data. The ECU is electrically connected to the parallel fuel injectors and throttle valves through a bus, and the bus is connected to the display fault lamp. If the ECU determines that the cylinder head is within the appropriate operating temperature range, the engine operates normally. If it determines that the cylinder head is in an over-temperature state, the ECU controls the display fault lamp to light up, and at the same time controls the throttle valve to limit the intake air volume and controls the fuel injector to limit the fuel injection volume.

[0012] The beneficial effects of the present invention are as follows:

[0013] 1. Through the design of the engine cylinder head cooling water jacket, it is ensured that the engine and the cylinder head are fully and efficiently cooled under normal cooling conditions, ensuring the reliability of the engine and the cylinder head;

[0014] 2. By designing a special temperature sensor in the water jacket on the exhaust side of the cylinder head to detect the metal temperature on the exhaust side of the cylinder head and monitor the operation of the cylinder head; ensuring that the cylinder head operates within a reasonable temperature range and guaranteeing the operation reliability of the engine and the cylinder head;

[0015] 3. When the metal temperature sensor of the cylinder head monitors that the temperature on the exhaust side of the cylinder head is abnormal, adjust the engine control strategy, and reduce the engine heat load through measures such as torque limitation / power limitation to ensure that the engine and the cylinder head do not overheat and are damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the present invention;

[0017] Figure 2 is a sectional view of the present invention;

[0018] Figure 3 is a circuit control schematic diagram of the present invention.

[0019] In the figure, 1 is the metal temperature sensor of the cylinder head, 2 is the cylinder head, 3 is the exhaust passage, 31 is the upper exhaust passage, 32 is the lower exhaust passage, 4 is the metal temperature sensor hole, 5 is the cooling water jacket, 6 is the ECU, 7 is the fuel injector, 8 is the throttle valve, and 9 is the display fault lamp. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The present invention will be further described below with reference to the drawings and embodiments:

[0021] See Figures 1-3 .

[0022] Such as Figure 1As shown in the figure, the present invention discloses an over-temperature protection structure for a cylinder head, which includes a cylinder head 2, an exhaust passage 3 and a cooling water jacket 5. The exhaust passage 3 includes an upper exhaust passage 31 and a lower exhaust passage 32, which are respectively arranged in the middle and below the front wall of the cylinder head 2 and communicate with the inner cavity of the cylinder head 2. Cooling water jackets 5 are provided on both sides of the cylinder head 2. A metal temperature sensor hole 4 is provided between the cooling water jacket 5 and the lower exhaust passage 32. A cylinder head metal temperature sensor 1 is fixed in the metal temperature sensor hole 4. The cylinder head metal temperature sensor 1 is arranged on the exhaust side of the cylinder head 2 near the high-temperature area of the cylinder head exhaust passage 3 to monitor the metal temperature of the key area of the cylinder head during the operation of the engine.

[0023] Requirements for the arrangement of the cylinder head metal temperature sensor:

[0024] 1. Overall position requirements: As Figure 2 shown, the cylinder head metal temperature sensor 1 needs to be arranged on the upper or lower side of the cylinder head exhaust passage 3, and it can be flexibly adjusted according to the shape of the sensor and the requirements of the engine arrangement;

[0025] 2. Accurate position: Combining the simulation analysis and calculation results of the temperature field of the engine cylinder head, the metal temperature sensor hole 4 is designed in the area with the highest metal temperature of the exhaust passage. For the cylinder head integrated double-flow exhaust passage structure, this position is generally between the upper exhaust passage 31 and the lower exhaust passage 32. In the corresponding invention, the metal temperature sensor hole 4 is arranged obliquely, and the distance between the closed end of the hole and the upper and lower exhaust passages is 4-5 mm. Purpose: One temperature sensor can synchronously and accurately monitor the temperature changes of the metal walls of the two exhaust passages, providing accurate data for the over-temperature protection of the cylinder head.

[0026] 3. Other requirements: There is no cooling water jacket 5 interval between the metal temperature sensor 1 and the cylinder head exhaust passage 3. The head of the metal temperature sensor 1 can be directly in contact with the bottom of the metal temperature sensor hole, which is convenient for the cylinder head technical temperature sensor to accurately obtain the temperature value of the cylinder head exhaust passage.

[0027] As Figure 3 shown, the cylinder head metal temperature sensor 1 feeds back the metal temperature data of the key area of the cylinder head 2 monitored to the ECU 6 for analysis. The ECU 6 judges whether the engine and the cylinder head 2 are in an over-temperature state according to the control strategy. If it is judged to be in the appropriate operating temperature range, the engine continues to operate normally; if it is judged that the engine and the cylinder head are in an over-temperature state, the ECU 6 controls to light up the fault lamp 9 on the display screen. Synchronously, the ECU 6 controls the throttle valve 8 to limit the intake air volume and controls the fuel injector 9 to limit the fuel injection volume, and limits the engine power and torque through the fuel injection volume and the intake air volume to reduce the engine heat load, thereby achieving the effect of protecting the engine and the cylinder head.

[0028] After the ECU 6 obtains the metal temperature of the key area of the cylinder head 2 monitored by the cylinder head metal temperature sensor 1:

[0029] 1. When the metal temperature in the key area of the cylinder head ≥ T1 (°C) and the time exceeds t1 (s), the ECU controls the engine to turn on the malfunction indicator lamp, but the engine does not perform torque limit / power limit protection; when the metal temperature of the engine cylinder head; when the metal temperature in the key area of the cylinder head ≤ T0 and the time exceeds t0, the malfunction is repaired and the engine malfunction indicator lamp is cancelled;

[0030] 2. When the metal temperature in the key area of the cylinder head ≥ T2 (°C), the ECU controls the engine to turn on the malfunction indicator lamp and simultaneously performs torque limit / power limit on the engine for engine protection. The torque limit process can refer to Figure 3 , control the engine intake air volume and fuel injection volume, or it can also be carried out by other methods of engine calibration. The torque limit coefficient can be controlled with reference to the engine over-temperature protection torque limit matrix (the torque limit matrix is calculated comprehensively based on engine speed, vehicle gear, vehicle speed, etc.). When the metal temperature in the key area of the cylinder head ≤ T4, the engine resumes torque / power and cancels the torque limit / power limit measures;

[0031] 3. When the metal temperature in the key area of the cylinder head ≥ T5 (°C), the ECU controls the engine to turn on the malfunction indicator lamp and simultaneously performs fuel cut-off protection on the engine. Conditions for entering the fuel cut-off protection strategy: ① The engine is in the idle state or the vehicle speed is zero; ② The vehicle is in the low-speed driving process and the output torque is below 50% of the corresponding external characteristic torque.

[0032] 4. Is the relationship between the above temperatures T0 < T1 < T4 < T2 < T5?

[0033] Example:

[0034] After the ECU6 obtains the metal temperature of the cylinder head monitored by the cylinder head metal temperature sensor 1 in the key area of the cylinder head 2:

[0035] 1. When the metal temperature in the key area of the cylinder head ≥ 160 °C and the time exceeds 10 s, the ECU6 controls the engine to turn on the malfunction indicator lamp, but the engine does not perform torque limit / power limit protection; when the metal temperature of the engine cylinder head; when the metal temperature in the key area of the cylinder head ≤ 150 °C and the time exceeds 10 s, the malfunction is repaired and the engine malfunction indicator lamp is cancelled;

[0036] 2. When the metal temperature in the key area of the cylinder head ≥ 190 °C, the ECU controls the engine to turn on the malfunction indicator lamp and simultaneously performs torque limit / power limit on the engine for engine protection. The torque limit process can refer to Figure 3 , control the engine intake air volume and fuel injection volume, or it can also be carried out by other methods of engine calibration. The torque limit coefficient can be controlled with reference to the engine over-temperature protection torque limit matrix (the torque limit matrix is calculated comprehensively based on engine speed, vehicle gear, vehicle speed, etc.). When the metal temperature in the key area of the cylinder head ≤ 170 °C, the engine resumes torque / power and cancels the torque limit / power limit measures;

[0037] 3. When the metal temperature in the key area of the cylinder head ≥ 230°C, the ECU controls the engine to turn on the malfunction indicator lamp, and simultaneously performs fuel cut protection on the engine. Conditions for entering the fuel cut protection strategy: ① The engine is in the idle state or the vehicle speed is zero; ② The vehicle is in the process of low-speed driving, and the output torque is below 50% of the corresponding external characteristic torque.

[0038] The above-described embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; therefore, although the present specification has described the present invention in detail with reference to the above-mentioned respective embodiments, those skilled in the art should understand that the present invention can still be modified or equivalently replaced; and all technical solutions and their improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. An over-temperature protection structure for a cylinder head, characterized in that: It includes a cylinder head (2), an exhaust passage (3) and a cooling water jacket (5). The exhaust passage (3) includes an upper exhaust passage (31) and a lower exhaust passage (32), which are respectively arranged in the middle and below the front wall of the cylinder head (2) and communicate with the inner cavity of the cylinder head (2). Cooling water jackets (5) are provided on both sides of the cylinder head (2). A metal temperature sensor hole (4) is provided between the cooling water jacket (5) and the lower exhaust passage (32), and a cylinder head metal temperature sensor (1) is fixed in the metal temperature sensor hole (4); the metal temperature sensor hole (4) is inclined, its closed end is located in the high-temperature area below the upper exhaust passage (31), and its open end obliquely penetrates downward through the outer wall of the cylinder head (2); the closed end of the metal temperature sensor hole (4) is located between the upper exhaust passage (31) and the lower exhaust passage (32), and the distances between the metal temperature sensor hole (4) and the upper exhaust passage (31) and the lower exhaust passage (32) are both 4-5 mm; the distances between the closed end of the metal temperature sensor hole (4) and the upper exhaust passage (31) and the lower exhaust passage (32) are equal.

2. The over-temperature protection structure of a cylinder head according to claim 1, characterized in that: The cylinder head metal temperature sensor (1) is electrically connected to an ECU (6) for transmitting metal temperature data. The ECU (6) is electrically connected to a parallel-connected fuel injector (7) and a throttle valve (8) through a bus, and the bus is connected to a display fault lamp (9); if the ECU (6) determines that the cylinder head (2) is within a suitable operating temperature range, the engine operates normally; if it determines that the cylinder head (2) is in an over-temperature state, the ECU (6) controls to light up the display fault lamp (9), and at the same time controls the throttle valve (8) to limit the intake air volume and controls the fuel injector (7) to limit the fuel injection volume.

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