A method for adjusting the performance of an engine with an ice zone exhaust gas bypass

Abstract

A method for adjusting the performance of an engine with ice-cold exhaust bypass is disclosed. The engine includes a supercharger, an exhaust manifold, a scavenging manifold, an exhaust bypass valve, a throttle orifice, and an engine control system. The method comprises: first, performing conventional engine configuration using a standard throttle orifice with a standard aperture in accordance with a conventional load control mode; then, replacing the standard throttle orifice with an ice-cold exhaust bypass orifice; adjusting the opening of the exhaust bypass valve to ensure that the engine's performance under various loads is consistent with that of a conventional configuration; and finally, completing the engine submission approval process. The engine's control mode is then changed to a non-load control mode, activating the ice-cold exhaust bypass control mode. The present invention enables the engine's performance to simultaneously meet the requirements of both conventional and ice-cold routes, effectively reducing fuel consumption and ensuring safe operation of the engine.

Description

Technical Field

[0001] The invention relates to main engine performance adjustment of a marine diesel engine, in particular to a main engine performance adjustment method with an ice zone exhaust gas bypass, and belongs to the technical field of marine diesel engines. Background Art

[0002] Currently, ship designs often use derated diesel engines, so engine performance optimization focuses on partial load or low load conditions. However, this often leads to excessively high scavenging pressure and overall nitrogen oxide emissions when marine diesel engines operate at high loads. For this reason, marine diesel engines are equipped with exhaust gas bypass devices, which allow a certain proportion of exhaust gas to be discharged directly without passing through the turbocharger, thereby reducing scavenging pressure and nitrogen oxide emissions under high loads. Figure 1 Schematic diagram of the exhaust bypass system for a low-speed marine diesel engine. Exhaust gas generated during operation is collected by an exhaust manifold 4, which then flows to a supercharger 1. This exhaust gas drives the supercharger's exhaust turbine, compressing the scavenging air and increasing the main engine's scavenging pressure and intake volume. The exhaust gas then passes through the supercharger 1 and enters the ship's exhaust piping. A wastegate valve 5 is located on the exhaust manifold 4, followed by a throttle orifice 6. A portion of the exhaust gas passes through this valve and orifice 6 and is discharged directly into the ship's exhaust pipe after the supercharger 1. The wastegate valve 5 comprises an actuator, control air, and a solenoid valve. It is connected to the main engine control system via a 4-20 mA current signal, which controls the opening of the wastegate valve 5.

[0003] The exhaust gas bypass ratio of the exhaust gas bypass device is generally fixed and is only opened under high load conditions. As global warming and glaciers melt, the number of ships operating on polar routes is increasing. Therefore, some ships use outboard air intake technology to achieve lower scavenging air temperatures and fuel consumption.

[0004] Under normal circumstances, the main engine draws air directly from the engine room, with scavenging air coming from the engine room, typically at a temperature of 0 to 45°C. However, switching to outboard intake allows for lower intake temperatures when operating in ice-covered areas, with temperatures reaching as low as -40°C. Generally, lower scavenging air temperatures also reduce diesel engine fuel consumption. Using outboard intake can significantly reduce diesel engine fuel consumption.

[0005] The conventional performance adjustment method for diesel engines with wastegate bypass is to control wastegate bypass according to load. At low load, the main engine control system closes wastegate valve 5. At high load, the control system opens wastegate valve 5 proportionally to the preset load, allowing a certain amount of exhaust gas to bypass through wastegate valve 5 and the throttle plate 6 behind the valve to prevent overspeed of the supercharger 1 and excessive scavenging pressure. During diesel engine factory testing, when the diesel engine is operating at its maximum load point, wastegate valve 5 is fully open. The actual measured scavenging pressure is compared with the expected value to determine the aperture size of throttle plate 6 behind wastegate valve 5. The characteristic of this performance adjustment method is that the wastegate bypass ratio is relatively fixed and is not affected by the opening degree of wastegate valve 5. This allows the performance evaluation of the supercharger 1 at the maximum load point to be unaffected during factory testing, thereby improving the accuracy of the performance evaluation of the supercharger 1.

[0006] However, the conventional method of adjusting the performance of marine diesel engines using exhaust gas bypass has the following disadvantages: first, the scavenging pressure adjustment range is limited. If the intake temperature is too low (reaching -40°C in extreme cases), even if the exhaust gas bypass valve 5 is fully opened, the scavenging pressure cannot be further reduced due to the limitation of the aperture of the throttle orifice 6, resulting in the risk of overspeed of the supercharger 1 when the main engine is running at high load; secondly, due to the limitations of the main engine's shaft system and combustion chamber, the cylinder pressure has a maximum limit value. If the main engine's intake temperature is too low, when it is running under partial load conditions, the exhaust gas bypass valve 5 using a load control strategy cannot effectively reduce the scavenging pressure at this time, which will cause the cylinder pressure to be too high and reach the maximum limit value. At this time, the main engine control system will reduce the cylinder pressure value to protect the mechanical components, but increase the fuel consumption rate of the main engine.

[0007] Therefore, the conventional exhaust gas bypass main engine performance adjustment method can neither meet the high-load safety requirements nor the economic requirements of partial-load operation for marine diesel engines with outboard air intake currently operating in ice areas. Summary of the Invention

[0008] In order to overcome the deficiencies of the above-mentioned prior art, the present invention proposes a method for adjusting the performance of an engine with an ice-area exhaust gas bypass, which completes the performance adjustment of the exhaust gas bypass engine under conventional environmental conditions, so that the engine performance can simultaneously meet the requirements of two different operating modes: conventional routes and ice-area routes. Under the premise of effectively reducing fuel consumption, the safe operation of the engine is ensured, so that marine diesel engines can play a more important role in polar shipping.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A method for adjusting the performance of an engine with an ice zone exhaust gas bypass, wherein the engine includes a turbocharger, an exhaust manifold, and a scavenging air manifold, and is equipped with an exhaust gas bypass device. The turbocharger is connected to an onboard exhaust pipe. The exhaust gas bypass device includes an exhaust gas bypass valve and a throttle orifice plate. The exhaust gas bypass valve is connected to the exhaust manifold and is controlled by the engine control system. The throttle orifice plate is connected after the exhaust gas bypass valve and is connected to the onboard exhaust pipe. The method for adjusting the performance of the engine includes:

[0011] First, use a standard throttle orifice with a standard aperture to perform conventional engine configuration in accordance with the conventional load control mode. Then replace the standard throttle orifice with an ice zone throttle orifice. By adjusting the opening of the exhaust gas bypass valve, the performance of the main engine under various loads is made consistent with the performance of the conventional engine configuration. After the main engine is submitted for approval, the control mode of the main engine is changed to the non-load control mode, and the ice zone exhaust gas bypass control mode of the main engine is activated.

[0012] Furthermore, the specific steps of the host performance adjustment method are as follows:

[0013] 1) Install a standard throttle orifice plate at the throttle orifice plate, set the host control mode to the conventional load control mode, complete conventional machine configuration, and record the host performance parameters;

[0014] 2) replacing the standard throttle orifice with an ice zone throttle orifice, changing the control mode of the main engine to another operating mode, adjusting the opening of the waste gas bypass valve so that the performance parameters of the main engine at various loads are consistent with the performance parameters of the conventional configuration in step 1), and writing the set values ​​of the scavenging air pressure range allowed at various loads into the main engine control system, thereby completing the ice zone configuration;

[0015] 3) Maintain the ice zone throttle orifice configuration status, submit the host in the load control mode, and after submission and approval, change the host control mode from load control mode to non-load control mode in the host control system, thereby activating the ice zone exhaust gas bypass function of the host.

[0016] Furthermore, compared with a standard throttle orifice plate, the ice region throttle orifice plate has a larger throttle aperture and a larger scavenging pressure adjustment range.

[0017] Furthermore, in the step 2), the other operating mode is a scavenging pressure control mode.

[0018] Furthermore, in the step 2), the performance parameter of the main engine under various loads refers to the scavenging pressure of the main engine.

[0019] Furthermore, in the step 3), the non-load control mode is a scavenging pressure closed-loop control mode.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1) The main engine performance adjustment method can complete the performance adjustment of the main engine with ice zone exhaust gas bypass under normal environmental conditions.

[0022] 2) The performance of the main engine after adjustment by the present invention takes into account two different operating modes: conventional routes and ice area routes, achieving the effect of effectively reducing fuel consumption and ensuring the safe operation of the main engine.

[0023] 3) The main engine adjusted by the present invention can simultaneously meet the performance requirements of operating under different routes, meeting the future demand of the polar shipping industry for ship diesel engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Layout diagram of the bypass device of the present invention.

[0025] Figure 2 Flowchart of the host performance adjustment method of the present invention.

[0026] In the figure,

[0027] 1 is the supercharger, 2 is the scavenging manifold, 4 is the exhaust manifold, 5 is the wastegate valve, and 6 is the throttle orifice. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, this does not limit the scope of protection of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0029] The present invention is used for adjusting the performance of the main engine of the exhaust gas bypass, so that the performance of the marine diesel engine after adjustment can adapt not only to the working conditions of conventional environmental routes, but also to the working conditions of icy environmental routes, thereby achieving the effect of reducing fuel consumption and nitrogen oxide emissions.

[0030] The method for adjusting the performance of the main engine with ice zone exhaust gas bypass of the present invention includes: first, according to the conventional load control mode, using a throttle plate with a standard throttle aperture to adjust the engine according to the conventional mode, and the throttle plate used at this time is a standard throttle plate with a smaller aperture Φ match In this conventional load control mode, complete the conventional turbocharger configuration and record the relevant performance parameters; then replace the throttle orifice with a larger ice zone throttle orifice with a larger aperture suitable for ice zone temperature with a larger scavenging pressure adjustment range. arctic By adjusting the opening of the wastegate valve, it can be aligned with the standard throttle orifice plate Φ matchThe scavenging pressure under each load is consistent, and the set value of the scavenging pressure range allowed for each load of the main engine is written into the main engine control system, and the factory test approval is completed; after the factory test approval, the control mode of the exhaust gas bypass valve is changed from the load control mode to the scavenging pressure closed-loop control mode in the main engine control system, and the ice area exhaust gas bypass control mode is activated.

[0031] Example

[0032] See also Figure 1 The marine diesel engine includes a supercharger 1, an exhaust manifold 4 and a scavenging manifold 2, the exhaust manifold 4 and the scavenging manifold 2 are connected to the supercharger 1, and the supercharger 1 is connected to the ship's exhaust pipe; the exhaust gas bypass device configured for the marine diesel engine includes an exhaust gas bypass valve 5 and a throttle orifice 6, the exhaust gas bypass valve 5 is connected to the exhaust manifold 4 and is controlled by the main engine control system, the throttle orifice 6 is connected after the exhaust gas bypass valve 5 and is connected to the ship's exhaust pipe, and part of the exhaust gas is directly discharged into the ship's exhaust pipe after the supercharger 1 through the exhaust gas bypass valve 5 and the throttle orifice 6.

[0033] See also Figure 2 The specific implementation steps of the host performance adjustment method of the present invention are as follows:

[0034] 1) First install the standard throttle orifice plate Φ at the throttle orifice plate 6 match , change the EGB control mode of the host to load control mode, and perform machine matching.

[0035] 2) After the machine is equipped, replace the throttle orifice plate 6 with the ice zone throttle orifice plate Φ arctic , change the EGB control mode to the scavenging pressure control mode, and match the machine according to the ice zone throttling orifice plate, and adjust the performance to the same as Φ match The performance parameters are consistent.

[0036] 3) Keep the ice zone throttle orifice installed and submit the test run in load control mode. After submission, turn off the load control mode and the ice zone exhaust gas bypass function will be activated.

[0037] When the marine diesel engine is running after adjustment, refer to Figure 1 The low-temperature air outside the ship during ice navigation or the ambient temperature air during normal navigation enters the supercharger 1 from the outboard air intake device, and the exhaust gas flows from the exhaust manifold 4 through the exhaust bypass valve 5 and the throttle orifice plate 6 into the turbine end of the supercharger 1, driving the supercharger 1 to operate and compress the fresh air input by the outboard air intake device.

Claims

1. A method for adjusting the performance of an engine with an ice zone exhaust gas bypass, wherein the engine comprises a turbocharger, an exhaust manifold, and a scavenging air manifold, and is equipped with an exhaust gas bypass device, wherein the turbocharger is connected to an onboard exhaust pipe, and the exhaust gas bypass device comprises an exhaust gas bypass valve and a throttle orifice plate, wherein the exhaust gas bypass valve is connected to the exhaust manifold and is controlled by the engine control system, and the throttle orifice plate is connected after the exhaust gas bypass valve and is connected to the onboard exhaust pipe, characterized in that: The host performance adjustment method includes: First, use a standard throttle orifice with a standard aperture to perform conventional engine configuration in accordance with the conventional load control mode. Then replace the standard throttle orifice with an ice zone throttle orifice. By adjusting the opening of the exhaust gas bypass valve, the performance of the main engine under various loads is made consistent with the performance of the conventional engine configuration. After the main engine is submitted for approval, the control mode of the main engine is changed to the non-load control mode, and the ice zone exhaust gas bypass control mode of the main engine is activated.

2. The method for adjusting the performance of an engine with an ice zone exhaust gas bypass according to claim 1, characterized in that: The specific steps of the host performance adjustment method are as follows: 1) Install a standard throttle orifice plate at the throttle orifice plate, set the host control mode to the conventional load control mode, complete conventional machine configuration, and record the host performance parameters; 2) replacing the standard throttle orifice with an ice zone throttle orifice, changing the control mode of the main engine to another operating mode, adjusting the opening of the waste gas bypass valve so that the performance parameters of the main engine at various loads are consistent with the performance parameters of the conventional configuration in step 1), and writing the set values ​​of the scavenging air pressure range allowed at various loads into the main engine control system, thereby completing the ice zone configuration; 3) Maintain the ice zone throttle orifice configuration status, submit the host in the load control mode, and after submission and approval, change the host control mode from load control mode to non-load control mode in the host control system, thereby activating the ice zone exhaust gas bypass function of the host.

3. The method for adjusting the performance of an engine with an ice zone exhaust gas bypass according to claim 1 or 2, characterized in that: Compared with a standard throttle orifice plate, the ice region throttle orifice plate has a larger throttle aperture and a larger scavenging pressure adjustment range.

4. The method for adjusting the performance of an engine with an ice zone exhaust gas bypass according to claim 2, characterized in that: In the step 2), the other operating mode is a scavenging pressure control mode.

5. The method for adjusting the performance of an engine with an ice zone exhaust gas bypass according to claim 2, characterized in that: In the step 2), the performance parameter of the main engine under various loads refers to the scavenging pressure of the main engine.

6. The method for adjusting the performance of an engine with an ice zone exhaust gas bypass according to claim 2, characterized in that: In the step 3), the non-load control mode is a scavenging pressure closed-loop control mode.

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