Diesel engine air inlet bypass structure based on two-stage pressurization system and control method
By designing an intake bypass structure for low-speed operation of the diesel engine, the problem of intake resistance at low speeds is solved, which bypasses the low-pressure stage compressor, improves the low-speed performance and fuel economy of the diesel engine, and maintains normal operation at high speeds.
Patent Information
- Application Number
- CN202610120426.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-28
- Publication Date
- 2026-03-03
AI Technical Summary
In existing two-stage turbocharging systems, under low-speed diesel engine conditions, the low-pressure stage compressor suffers from insufficient exhaust energy, leading to intake resistance, which affects intake volume and efficiency, resulting in low low-speed torque, sluggish power response, and poor fuel economy.
Design an intake bypass structure that, through pressure valve control, bypasses the low-pressure stage compressor and directly enters the high-pressure stage compressor under low-speed conditions. By utilizing the bypass pipeline and pressure valve, the airflow is short-circuited at low speeds, preventing the low-pressure stage compressor from becoming an intake resistance.
It significantly improves intake volume and efficiency at low speeds, enhances low-speed torque and power response of diesel engines, while maintaining normal coordinated operation at high speeds, thereby improving overall performance and fuel economy.
Smart Images
Figure CN121593891A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of diesel engine technology, and in particular relates to the intake bypass structure and control method of a diesel engine based on a two-stage turbocharging system. Background Technology
[0002] Two-stage turbocharging systems are widely used in the design of high-power diesel engines because they can meet the power requirements of both high and low speed conditions. Existing two-stage turbocharging systems typically employ a series structure of a low-pressure stage turbocharger and a high-pressure stage turbocharger. To meet the boost demands under high speed and heavy load, the compressor size of the low-pressure stage turbocharger is often larger than that of the high-pressure stage turbocharger. However, when the diesel engine is running at low speeds, the exhaust energy is low and insufficient to drive the low-pressure stage turbocharger to operate normally. At this time, the compressor of the low-pressure stage turbocharger is in a state of "passive rotation" or "stationary". Due to the large size of the low-pressure stage compressor, its internal flow resistance is significant, which creates additional obstacles to the intake system, leading to insufficient intake volume and reduced intake efficiency. This, in turn, causes problems such as low low-speed torque, sluggish power response, and poor fuel economy, limiting the performance of the two-stage turbocharging system under low-speed conditions. Currently, there is no effective solution to this problem. Existing technologies mostly focus on optimizing the turbocharger's structure or adjusting control strategies, failing to fundamentally eliminate the intake resistance of the low-pressure stage compressor at low speeds. Therefore, to address the issue of the low-pressure stage compressor becoming an intake drag in existing two-stage turbocharged systems under low-speed conditions, this invention designs an intake bypass structure. When the diesel engine is running at low speed, a pressure valve controls the intake airflow to bypass the low-pressure stage compressor and directly enter the high-pressure stage compressor, thereby reducing intake resistance and improving low-speed performance. Summary of the Invention
[0003] In view of this, the present invention aims to propose a diesel engine intake bypass structure and control method based on a two-stage turbocharging system to solve the intake resistance problem of the low-pressure stage compressor at low speeds in a two-stage turbocharged diesel engine.
[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows: In a first aspect, the present invention provides a diesel engine intake bypass structure based on a two-stage turbocharging system, characterized in that it includes a bypass pipeline and a pressure valve; One end of the bypass line is connected to the main intake pipe at the inlet of the low-pressure stage compressor; the other end of the bypass line is connected to the main intake pipe. The pressure valve is used to control the opening and closing of the bypass pipeline; The pressure valve is located inside the bypass pipeline; The pressure valve is set to the normally open state.
[0005] Furthermore, the pressure valve is configured as a spring pressure valve, which is connected to the outlet of the high-pressure stage compressor via the air intake pipe after the high-pressure stage compressor.
[0006] Furthermore, the pressure valve is configured as a solenoid valve, which is connected to the ECU. The ECU is connected to the AD converter, which is connected to the amplification and shaping circuit module. The amplification and shaping circuit module is connected to the intake pressure sensor, which is located at the outlet of the high-pressure stage compressor.
[0007] Furthermore, the main intake pipe is the pipeline between the outlet of the low-pressure stage compressor and the inlet of the high-pressure stage compressor.
[0008] Secondly, based on the same concept and considering that the pressure valve is a spring-loaded pressure valve, the present invention also provides a control method for a diesel engine intake bypass structure based on a two-stage turbocharging system, comprising the following steps: A1. Set the closing threshold of the spring pressure valve, set the diameter of the bypass pipe, and optimize the connection position of the bypass pipe. A2. Before starting the diesel engine, the spring pressure valve is in the normally open position and the bypass line is open; A3. After the diesel engine starts, when it is in the low-speed operation stage, the exhaust energy is insufficient, the turbine of the low-pressure stage turbocharger cannot drive the compressor impeller normally, the outlet pressure after the high-pressure stage compressor is lower than the closing threshold of the spring pressure valve, the spring pressure valve opens, the bypass line opens, and part or all of the air enters the high-pressure stage compressor directly through the bypass line. A4. When in the high-speed operation stage, the exhaust energy increases, and the outlet pressure after the high-pressure stage compressor gradually rises to a level higher than the closing threshold of the spring pressure valve. The spring pressure valve closes, the bypass pipeline is disconnected, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
[0009] Furthermore, in step A1, the closing threshold of the spring pressure valve is set, the diameter of the bypass pipe is set, and the connection position of the bypass pipe is optimized, including: Based on the diesel engine model and turbocharger system parameters, the closing threshold of the spring pressure valve is set, and the diameter of the bypass pipe is set; based on the engine compartment layout, the connection position of the bypass pipe is adjusted and optimized.
[0010] For cases where the pressure valve is a solenoid valve, a control method for a diesel engine intake bypass structure based on a two-stage turbocharging system is also provided, including the following steps: B1. Set the closing threshold of the solenoid valve, set the diameter of the bypass pipe, and optimize the connection position of the bypass pipe. B2. Before the diesel engine starts, the ECU is powered on, and the intake pressure sensor detects the outlet pressure after the high-pressure stage compressor. If the pressure is 0, which is less than the closing threshold P of the solenoid valve, the ECU controls the solenoid valve to open, the bypass line is opened, and part or all of the air enters the high-pressure stage compressor directly through the short-circuit line. B3. After the diesel engine starts, when it is in the low-speed operation stage, the intake pressure sensor detects the outlet pressure P1 after the high-pressure stage compressor. If P1≤P, the ECU controls the solenoid valve to remain open and the bypass line remains open. B4. As the diesel engine speed and load increase, the intake pressure sensor detects the outlet pressure P2 after the high-pressure stage compressor. If P2 > P, the ECU controls the pressure valve to close, the bypass line to disconnect, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
[0011] Furthermore, in step B1, the closing threshold of the solenoid valve is set, the diameter of the bypass pipe is set, and the connection position of the bypass pipe is optimized, including: Based on the diesel engine model and turbocharger system parameters, the closing threshold of the solenoid valve is set and stored in the ECU, and the diameter of the bypass pipe is set; based on the engine compartment layout, the connection position of the bypass pipe is adjusted and optimized.
[0012] Compared with the prior art, the diesel engine intake bypass structure and control method based on a two-stage turbocharging system described in this invention has the following advantages: (1) It solves the problem of intake resistance of the low-pressure stage compressor in a two-stage turbocharged diesel engine at low speed, significantly improves the intake volume and intake efficiency at low speed, and thus improves the low-speed torque and power response speed of the diesel engine.
[0013] (2) The structure is simple. The function can be realized by simply adding a bypass pipeline and a pressure valve. There is no need to make significant changes to the core structure of the original two-stage booster system. The modification cost is low and the compatibility is strong.
[0014] (3) It does not affect the normal coordinated operation of the two-stage turbocharger under high-speed conditions of the diesel engine, takes into account the performance requirements of high and low speed conditions, and improves the overall operating performance and fuel economy of the diesel engine. Attached Figure Description
[0015] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a connection diagram of the diesel engine intake bypass structure based on a two-stage turbocharging system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the connection of the diesel engine intake bypass structure when the spring pressure valve is open, as described in an embodiment of the present invention. Figure 3 This is a schematic diagram of the connection of the diesel engine intake bypass structure when the spring pressure valve is closed, as described in an embodiment of the present invention. Figure 4 This is a schematic diagram of the connection of the diesel engine intake bypass structure when the pressure valve is a solenoid valve according to an embodiment of the present invention.
[0016] Explanation of reference numerals in the attached figures: 1. High-pressure stage compressor rear air intake pipe; 2. Support housing; 3. Sealing ring; 4. Spring; 5. Valve; 6. Bypass pipeline. Detailed Implementation
[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.
[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0021] like Figures 1 to 4 As shown, the intake bypass structure and control method of a diesel engine based on a two-stage turbocharging system improves the intake efficiency and power performance of the diesel engine at low speeds by "short-circuiting" the compressor of the low-pressure stage turbocharger under specific operating conditions, thus preventing it from becoming an intake resistance.
[0022] Specifically as follows: The low-pressure stage turbocharger and the high-pressure stage turbocharger are connected in series along the intake direction. The compressor outlet of the low-pressure stage turbocharger is connected to the compressor inlet of the high-pressure stage turbocharger through the main intake pipeline. The turbine of the low-pressure stage turbocharger and the turbine of the high-pressure stage turbocharger are connected in series along the exhaust direction.
[0023] One end of the bypass line 6 is connected to the intake manifold at the front end of the compressor inlet of the low-pressure stage turbocharger, and the other end is connected to the main intake line, that is, the line between the outlet of the low-pressure stage compressor and the inlet of the high-pressure stage compressor, forming a bypass channel across the low-pressure stage compressor.
[0024] The pressure valve is fixedly installed inside the bypass line 6 and is used to control the opening and closing of the bypass line 6. The pressure valve is normally open and its closing pressure threshold is set according to the exhaust pressure after the high-pressure stage compressor of the diesel engine under low-speed conditions, and is calibrated according to the specific model of the diesel engine.
[0025] When the diesel engine is running at low speed, the outlet pressure after the compressor of the high-pressure stage turbocharger is lower than the pressure valve threshold, the pressure valve opens, and the bypass line 6 is open. Part or all of the air enters the high-pressure stage compressor directly through the bypass line 6, effectively "short-circuiting" the low-pressure stage compressor. When the diesel engine speed increases, the outlet pressure after the high-pressure stage compressor reaches or exceeds the pressure valve's closing threshold, which is the critical speed at which the low-pressure stage turbocharger begins normal pressure build-up. The pressure valve automatically closes, and all the air enters the high-pressure stage compressor after the low-pressure stage compressor.
[0026] Example 1: The pressure valve is a spring pressure valve The spring pressure valve includes a spring 4, a support housing 2, a sealing ring 3, and a valve 5. The spring pressure valve is connected to the outlet of the high-pressure stage compressor through the air intake pipe 1 after the high-pressure stage compressor. When the spring 4 is in a free state, the spring pressure valve is in a normally open state. When the diesel engine speed is lower than 1300 r / min (low-speed condition), the exhaust energy is insufficient, and the turbine of the low-pressure stage turbocharger cannot drive the compressor impeller normally. At this time, the outlet pressure after the high-pressure stage compressor is lower than the closing threshold of the pressure valve, the pressure valve remains open, the bypass pipe 6 is opened, and part or all of the air enters the high-pressure stage compressor directly through the short-circuit pipe, realizing the "short circuit" of the low-pressure stage compressor.
[0027] When the diesel engine speed increases to above 1300 r / min, the exhaust energy increases, the outlet pressure after the high-pressure stage compressor gradually increases, the pressure valve automatically closes, the bypass line 6 is disconnected, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
[0028] Example 2: The pressure valve is a solenoid valve The solenoid valve is connected to the ECU, the ECU is connected to the AD converter, the AD converter is connected to the amplification and shaping circuit module, the amplification and shaping circuit module is connected to the intake pressure sensor, and the intake pressure sensor is located at the outlet of the high-pressure stage compressor.
[0029] The intake pressure sensor is used to detect diesel engine operating parameter signals; the amplification and shaping circuit module is used to process the sensor's operating parameter signals into digital signals, or to process the sensor's operating parameter signals and output them to the AD converter; the AD converter is used to receive the analog operating parameter signals output by the amplification and shaping circuit and convert them into digital signals; the ECU is used to receive the digital signals output by the amplification and shaping circuit or the AD converter, compare and calculate them with the set diesel engine operating parameters, and then output control signals; the solenoid valve is used to receive the control signals output by the ECU and control the opening and closing of the solenoid valve; the intake pressure sensor, the amplification and shaping circuit module, the AD converter, the ECU, and the ECU are integrated into the diesel engine electronic control system.
[0030] Step 1: Before starting the diesel engine, the ECU is powered on. The intake pressure sensor detects the outlet pressure after the high-pressure stage compressor. The pressure is 0, which is less than the solenoid valve pressure threshold P (this value can be calibrated). The ECU controls the solenoid valve to open, and the bypass line 6 is opened. Part or all of the air enters the high-pressure stage compressor directly through the short-circuit line, realizing the "short circuit" of the low-pressure stage compressor.
[0031] Step 2: After the diesel engine starts and reaches low-speed operation, the intake pressure sensor detects the pressure P1 after the high-pressure stage. If P1≤P, the ECU controls the solenoid valve to remain open, and the bypass line 6 remains open.
[0032] Step 3: As the diesel engine speed and load increase, the intake pressure sensor detects the high-pressure stage compressor outlet pressure P2. If P2 > P, the ECU controls the pressure valve to close, the bypass line 6 is disconnected, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
[0033] It should be noted that the opening pressure of the pressure valve and the diameter of the short-circuit pipe can be adjusted according to the specific model of the diesel engine and the parameters of the turbocharging system. The connection position of the short-circuit pipe can also be adapted and optimized according to the engine compartment layout.
[0034] The beneficial effects of this invention are: (1) It solves the problem of intake resistance of the low-pressure stage compressor in a two-stage turbocharged diesel engine at low speed, significantly improves the intake volume and intake efficiency at low speed, and thus improves the low-speed torque and power response speed of the diesel engine.
[0035] (2) The structure is simple. The function can be realized by simply adding a bypass pipeline and a pressure valve. There is no need to make significant changes to the core structure of the original two-stage booster system. The modification cost is low and the compatibility is strong.
[0036] (3) It does not affect the normal coordinated operation of the two-stage turbocharger under high-speed conditions of the diesel engine, takes into account the performance requirements of high and low speed conditions, and improves the overall operating performance and fuel economy of the diesel engine.
[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A diesel engine intake bypass structure based on a two-stage turbocharging system, characterized in that: Includes bypass piping (6) and pressure valves; One end of the bypass pipe (6) is connected to the main intake pipe at the inlet front end of the low-pressure stage compressor; the other end of the bypass pipe (6) is connected to the main intake pipe. The pressure valve is used to control the opening and closing of the bypass line (6); The pressure valve is located inside the bypass pipeline (6); The pressure valve is set to the normally open state.
2. The diesel engine intake bypass structure based on a two-stage turbocharging system according to claim 1, characterized in that: The pressure valve is a spring pressure valve, which is connected to the outlet of the high-pressure compressor through the air intake pipe (1) of the high-pressure compressor.
3. The diesel engine intake bypass structure based on a two-stage turbocharging system according to claim 1, characterized in that: The pressure valve is a solenoid valve, which is connected to the ECU. The ECU is connected to the AD converter, which is connected to the amplification and shaping circuit module. The amplification and shaping circuit module is connected to the intake pressure sensor, which is located at the outlet of the high-pressure stage compressor.
4. The diesel engine intake bypass structure based on a two-stage turbocharging system according to claim 1, characterized in that: The main intake pipe is the pipeline between the outlet of the low-pressure stage compressor and the inlet of the high-pressure stage compressor.
5. A control method for a diesel engine intake bypass structure based on a two-stage turbocharging system, applied to the diesel engine intake bypass structure based on a two-stage turbocharging system as described in any one of claims 1, 2, and 4, comprising the following steps: A1. Set the closing threshold of the spring pressure valve, set the diameter of the bypass pipe, and optimize the connection position of the bypass pipe. A2. Before starting the diesel engine, the spring pressure valve is in the normally open position and the bypass line is open; A3. After the diesel engine starts, when it is in the low-speed operation stage, the exhaust energy is insufficient, the turbine of the low-pressure stage turbocharger cannot drive the compressor impeller normally, the outlet pressure after the high-pressure stage compressor is lower than the closing threshold of the spring pressure valve, the spring pressure valve opens, the bypass line opens, and part or all of the air enters the high-pressure stage compressor directly through the bypass line. A4. When in the high-speed operation stage, the exhaust energy increases, and the outlet pressure after the high-pressure stage compressor gradually rises to above the closing threshold of the spring pressure valve. The spring pressure valve closes, the bypass pipeline is disconnected, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
6. The control method for the intake bypass structure of a diesel engine based on a two-stage turbocharging system according to claim 5, characterized in that: In step A1, the closing threshold of the spring pressure valve is set, the diameter of the bypass pipe is set, and the connection position of the bypass pipe is optimized, including: Based on the diesel engine model and turbocharger system parameters, the closing threshold of the spring pressure valve is set, and the diameter of the bypass pipe is set; based on the engine compartment layout, the connection position of the bypass pipe is adjusted and optimized.
7. A control method for a diesel engine intake bypass structure based on a two-stage turbocharging system, applied to the diesel engine intake bypass structure based on a two-stage turbocharging system as described in any one of claims 1, 3, and 4, characterized in that: Includes the following steps: B1. Set the closing threshold of the solenoid valve, set the diameter of the bypass pipe, and optimize the connection position of the bypass pipe. B2. Before the diesel engine starts, the ECU is powered on, and the intake pressure sensor detects the outlet pressure after the high-pressure stage compressor. If the pressure is 0, which is less than the closing threshold P of the solenoid valve, the ECU controls the solenoid valve to open, the bypass line is opened, and part or all of the air enters the high-pressure stage compressor directly through the short-circuit line. B3. After the diesel engine starts, when it is in the low-speed operation stage, the intake pressure sensor detects the outlet pressure P1 after the high-pressure stage compressor. If P1≤P, the ECU controls the solenoid valve to remain open and the bypass line remains open. B4. As the diesel engine speed and load increase, the intake pressure sensor detects the outlet pressure P2 after the high-pressure stage compressor. If P2 > P, the ECU controls the pressure valve to close, the bypass line to disconnect, and all the air enters the high-pressure stage compressor after being pressurized by the low-pressure stage compressor.
8. The control method for the intake bypass structure of a diesel engine based on a two-stage turbocharging system according to claim 7, characterized in that: In step B1, the closing threshold of the solenoid valve is set, the diameter of the bypass pipe is set, and the connection position of the bypass pipe is optimized, including: Based on the diesel engine model and turbocharger system parameters, the closing threshold of the solenoid valve is set and stored in the ECU, and the diameter of the bypass pipe is set; based on the engine compartment layout, the connection position of the bypass pipe is adjusted and optimized.