Ammonia gas engine system and injection control method thereof

Abstract

The invention discloses an ammonia gas engine system and an injection control method thereof, belongs to the technical field of ammonia gas engines, and solves the technical problem that the ammonia gas suction volumes of all air cylinders are different due to the structural difference between nozzles. The system comprises an engine body, an ammonia gas cylinder set, an ammonia gas distributor and a control unit, the ammonia gas distributor comprises a gas track chamber, a plurality of injection valves and a common rail chamber, the ammonia gas cylinder set is connected with the gas track chamber through a first ammonia gas pipe, the gas track chamber is connected with the common rail chamber through the injection valves, and a mixer and a throttle valve are arranged on a gas inlet pipe of the engine body. The common rail chamber is connected with the mixer through a second ammonia gas pipe, and the control unit is electrically connected with the injection valve. According to the control method, the injection valves are grouped, and the injection valves are alternately used according to the working condition sequence, so that the performance and emission difference of the engine in the using period of different injection valves is reduced, the performance of the whole engine is improved, emission is reduced, the loss difference of all the nozzles is reduced, and the service life of an engine system is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia engines, and more specifically, to an ammonia engine system and an injection control method thereof. Background Art

[0002] At present, motor vehicle exhaust emissions have become an important factor affecting air pollution. NOx is one of the main pollutants in exhaust emissions. Automobile exhaust control and pollution management have become an important part of sustainable development.

[0003] In the context of "carbon neutrality", ammonia, as a 100% renewable zero-carbon fuel, can power ships, trucks and engineering vehicles, and has great potential in the transition from fossil fuels to zero-carbon fuels. Ammonia is an easily liquefied gas. When cooled to -33.4°C at normal pressure or pressurized to 7-8 atmospheres at normal temperature, ammonia will liquefy into a colorless liquid. The easy liquefaction and zero-carbon properties of ammonia make it very suitable as a fuel for internal combustion engines.

[0004] For an ammonia engine with multiple cylinders, ammonia from an ammonia bottle delivers fuel gas to the engine through multiple injection valves in the distributor. Usually, when the engine is working smoothly, the opening time of each injection valve is the same. Due to structural differences between the nozzles (production tolerance, part tolerance, installation tolerance, etc.), there will be differences in the amount of ammonia inhaled by each cylinder, resulting in different working performance of each cylinder, which in turn affects the performance and emissions of the entire engine. Summary of the invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. One purpose of the present invention is to provide an ammonia engine system to reduce the differences in engine performance and emissions during use of different nozzles.

[0006] A second objective of the present invention is to provide an injection control method for an ammonia engine system.

[0007] In order to achieve the above-mentioned purpose one, the present invention provides an ammonia engine system, including an engine body, and also including an ammonia bottle group, an ammonia distributor, and a control unit. The ammonia distributor includes an air rail chamber, multiple injection valves, and a common rail chamber. The ammonia bottle group is connected to the air rail chamber through a first ammonia pipe, and the air rail chamber is connected to the common rail chamber through multiple injection valves. A mixer and a throttle are sequentially provided on the intake pipe of the engine body, and the common rail chamber is connected to the mixer through a second ammonia pipe, and the control unit is electrically connected to the injection valve.

[0008] As a further improvement, the first ammonia pipe is provided with a main valve, a liquid ammonia filter, and a pressure regulating valve in sequence.

[0009] Further, a first pressure gauge is provided on the first ammonia pipe at the input end of the master valve.

[0010] Further, a second pressure gauge is provided on the first ammonia pipe at the output end of the pressure stabilizing valve.

[0011] Further, a flowmeter is also provided on the first ammonia pipe at the output end of the pressure stabilizing valve.

[0012] Further, the number of the injection valves is a multiple of 6.

[0013] To achieve the above-mentioned second object, the present invention provides an injection control method for an ammonia engine system, setting the opening sequence of each injection valve, and keeping the injection pulse width length for each injection valve to be opened consistent;

[0014] The injection valves are evenly divided into N groups, where N≥3;

[0015] Determine the basic ammonia injection amount according to the current operating condition of the ammonia engine, and then determine the number of groups M of injection valves that need to be put into operation according to the basic ammonia injection amount;

[0016] When M<N, arrange the N groups of injection valves in a circular permutation; starting from the first group, sequentially select M groups of injection valves in the circular permutation to supply ammonia. After using the cycle time T; then sequentially start from the next group and sequentially select M groups of injection valves in the circular permutation to supply ammonia; in this way, sequentially and circularly select M groups of injection valves to supply ammonia to ensure that each injection valve is used alternately;

[0017] When M = N, all injection valves supply ammonia according to the opening sequence.

[0018] As a further improvement, the number of the injection valves is 6. The opening sequence of the 6 injection valves is 1-5-3-6-2-4, and the opening interval time is t / 6, where t is the pulse period of the injection valve working. The 6 injection valves are evenly divided into 3 adjacent groups.

[0019] Further, when the ammonia engine is in an idle running or low load condition, the number of groups of injection valves that need to be put into operation is 1 group;

[0020] When the ammonia engine is in a medium speed and medium-high load condition, the number of groups of injection valves that need to be put into operation is 2 groups;

[0021] When the ammonia intake demand of the operating condition of the ammonia engine requires 3 groups of injection valves to provide, then all injection valves are fully enabled and supply ammonia according to the opening sequence.

[0022] Furthermore, the injection pulse width MAP table is pre-calibrated based on the engine speed and intake pressure as independent variables; in actual work, the injection pulse width MAP table is queried according to the actual speed and intake pressure to obtain the injection pulse width, and the operation of each injection valve is controlled according to the injection pulse width.

[0023] Beneficial Effects

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The present invention divides the injection valves into groups, determines the number of injection valve groups that need to be put into operation according to the working conditions, and uses the injection valves in sequence and in rotation, so as to reduce the differences in engine performance and emissions during the use of different injection valves, improve the performance of the entire engine and reduce emissions, reduce the loss differences of each nozzle, and increase the life of the engine system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural principle diagram of the present invention;

[0027] Figure 2 It is a schematic diagram of the injection strategy for the first cycle time T under idle and low speed conditions;

[0028] Figure 3 It is a schematic diagram of the injection strategy for the second cycle time T under idle and low speed conditions;

[0029] Figure 4 Schematic diagram of the injection strategy for the first cycle time T under medium speed and medium to high load conditions;

[0030] Figure 5 Schematic diagram of the injection strategy for the second cycle time T under medium speed and medium to high load conditions;

[0031] Figure 6 Schematic diagram of the injection strategy for the cycle time T under high-speed and high-load conditions.

[0032] Among them: 1-engine body, 2-ammonia cylinder group, 3-ammonia distributor, 4-control unit, 5-air rail chamber, 6-injection valve, 7-common rail chamber, 8-first ammonia pipe, 9-intake pipe, 10-mixer, 11-throttle, 12-second ammonia pipe, 13-main valve, 14-liquid ammonia filter, 15-pressure regulating valve, 16-first pressure gauge, 17-second pressure gauge, 18-flow meter. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.

[0034] See also Figure 1 to Figure 6An ammonia engine system includes an engine body 1, an ammonia cylinder group 2, an ammonia distributor 3, and a control unit 4. The ammonia distributor 3 includes a rail chamber 5, a plurality of injection valves 6, and a common rail chamber 7. The ammonia cylinder group 2 is connected to the rail chamber 5 through a first ammonia pipe 8, and the rail chamber 5 is connected to the common rail chamber 7 through a plurality of injection valves 6. A mixer 10 and a throttle valve 11 are sequentially arranged on the intake pipe 9 of the engine body 1. The common rail chamber 7 is connected to the mixer 10 through a second ammonia pipe 12. The control unit 4 is electrically connected to the injection valve 6. Each injection valve 6 is in the form of a solenoid valve, which is opened when powered on and closed when powered off. The control unit 4 is used to control the operation of the entire ammonia engine system.

[0035] Furthermore, the first ammonia pipe 8 is provided with a main valve 13 , a liquid ammonia filter 14 , and a pressure regulating valve 15 in sequence.

[0036] The ammonia cylinder group 2 stores liquefied ammonia. When the main valve 13 is opened, the ammonia is reduced in pressure to the required low pressure through the liquid ammonia filter 14 and the pressure regulating valve 15, and then supplied to the engine through the ammonia distributor 3. After the ammonia is mixed with fresh air in the mixer 10, it flows into the engine cylinder for combustion.

[0037] The first ammonia pipe 8 at the input end of the main valve 13 is provided with a first pressure gauge 16 for detecting the air pressure of the ammonia cylinder group 2. The first ammonia pipe 8 at the output end of the pressure regulating valve 15 is provided with a second pressure gauge 17 for detecting the air pressure after the pressure regulating valve 15 is decompressed. Preferably, the first pressure gauge 16 and the second pressure gauge 17 are both electronic pressure gauges, which are electrically connected to the control unit 4. When the control unit 4 detects that the air pressure of the ammonia cylinder group 2 or the air pressure after decompression is abnormal, an alarm message is issued.

[0038] The first ammonia pipe 8 at the output end of the pressure regulating valve 15 is also provided with a flow meter 18 for detecting the flow of ammonia and sending it to the control unit 4 .

[0039] Preferably, the number of injection valves 6 is a multiple of 6, such as 6 or 12.

[0040] An injection control method for an ammonia engine system is specifically as follows: setting the opening order of each injection valve 6, and each injection valve 6 is kept open with a consistent injection pulse width;

[0041] The injection valves 6 are evenly divided into N groups, where N ≥ 3;

[0042] Determine the basic ammonia injection amount according to the current operating condition of the ammonia engine, and then determine the number of injection valve groups M that need to be put into operation according to the basic ammonia injection amount;

[0043] When M < N, the N groups of injection valves 6 are arranged in a circular permutation; starting from the first group, M groups of injection valves 6 are sequentially selected in the circular permutation for supplying ammonia gas. After using the cycle time T; then starting from the next group in sequence, M groups of injection valves 6 are sequentially selected in the circular permutation for supplying ammonia gas; thus, M groups of injection valves 6 are sequentially and circularly selected for supplying ammonia gas to ensure that each injection valve 6 is used alternately.

[0044] When M = N, all the injection valves 6 supply ammonia gas in the opening order.

[0045] In this embodiment, the number of injection valves 6 is 6. The opening order of the 6 injection valves 6 is 1 - 5 - 3 - 6 - 2 - 4, and the opening interval time is t / 6, where t is the pulse period of the operation of the injection valve 6. The 6 injection valves 6 are evenly divided into 3 adjacent groups.

[0046] If the 6 injection valves are sequentially labeled as I1, I2, I3, I4, I5, I6, that is, the injection valves I1 and I2 are set as the first group, the injection valves I3 and I4 are set as the second group, and the injection valves I5 and I6 are set as the third group.

[0047] When the ammonia engine is in the idle running or low - load working condition, the number of groups of injection valves that need to be put into operation is 1 group. Only control one group of injection valves to sequentially supply ammonia gas to the engine. As Figure 2 shown, in the first cycle time T of the engine, the control unit controls the injection valves (I1, I2) to supply ammonia gas to the engine. Figure 2 The figure shows the process of the injection valve opening, remaining open, and closing in the cycle time T in a stepped - shaped curve.

[0048] After the first group of injection valves has been used for the cycle time T, the control unit will switch to the second group of injection valves (I3, I4) to inject ammonia gas, as Figure 3 shown.

[0049] After the second group of injection valves has been used for a cycle time T, the control unit will switch to the third group of injection valves (I5, I6), and then the control unit will switch back to the first group of injection valves, by rotating the use of the nozzles in this way.

[0050] When the ammonia engine is in the medium - speed and medium - high - load working condition, the ammonia intake requirement needs 2 groups of injection valves to provide, and the number of groups of injection valves that need to be put into operation is 2 groups. As Figure 4 shown, in the first cycle time T of the engine, the control unit controls the first group of injection valves (I1, I2) and the second group of injection valves (I3, I4) to sequentially inject ammonia gas into the common - rail chamber.待到第二循环时间T时,关闭第一组喷射阀,启用第三组喷射阀(I5、I6)并入喷射,如 Figure 5When the third cycle time T comes, the second group of injection valves is closed, and the first group of injection valves is enabled to supply ammonia, and so on.

[0051] The three groups of injection valves work in rotation, which can ensure the uniformity of the use of each nozzle, thereby reducing the differences in engine performance and emissions during the use of different nozzles, and reducing the wear differences of each nozzle, thereby increasing the life of the engine system.

[0052] When the ammonia intake demand of the ammonia engine operating condition requires three groups of injection valves to provide, such as high-speed and high-load conditions, all injection valves 6 are enabled and supply ammonia in the order of opening, such as Figure 6 shown.

[0053] The engine's low-load operating conditions, medium-speed medium-high load operating conditions, and high-speed high-load operating conditions are calibrable, that is, the engine speed and torque are divided into zones according to the ammonia demand, so that the number of injection valves working simultaneously can be accurately controlled.

[0054] The injection pulse width MAP table can be calibrated in advance based on the engine speed and intake pressure as independent variables. In actual work, the injection pulse width MAP table is queried according to the actual speed and intake pressure to obtain the injection pulse width, and the operation of each injection valve 6 is controlled according to the injection pulse width.

[0055] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. An ammonia engine system, comprising an engine body (1), characterized in that: It further includes an ammonia gas cylinder group (2), an ammonia gas distributor (3), and a control unit (4). The ammonia gas distributor (3) includes a gas rail chamber (5), a plurality of injection valves (6), and a common rail chamber (7). The ammonia gas cylinder group (2) is connected to the gas rail chamber (5) through a first ammonia gas pipe (8). The gas rail chamber (5) is connected to the common rail chamber (7) through the plurality of injection valves (6). A mixer (10) and a throttle valve (11) are sequentially arranged on the intake pipe (9) of the engine body (1). The common rail chamber (7) is connected to the mixer (10) through a second ammonia gas pipe (12). The control unit (4) is electrically connected to the injection valves (6).

2. The ammonia engine system according to claim 1, characterized in that: A main valve (13), a liquid ammonia filter (14), and a pressure stabilizing valve (15) are sequentially arranged on the first ammonia gas pipe (8).

3. The ammonia engine system according to claim 2, characterized in that: A first pressure gauge (16) is arranged on the first ammonia gas pipe (8) at the input end of the main valve (13).

4. The ammonia engine system according to claim 2, characterized in that: A second pressure gauge (17) is arranged on the first ammonia gas pipe (8) at the output end of the pressure stabilizing valve (15).

5. The ammonia engine system according to claim 2, characterized in that: A flow meter (18) is also arranged on the first ammonia gas pipe (8) at the output end of the pressure stabilizing valve (15).

6. The ammonia engine system according to claim 1, characterized in that: The number of the injection valves (6) is a multiple of 6.

7. An injection control method for an ammonia engine system, characterized in that: Set the opening sequence of each injection valve (6), and the injection pulse width lengths for which each injection valve (6) remains open are the same; The injection valves (6) are evenly divided into N groups, where N≥3; Determine the basic ammonia gas injection amount according to the current operating condition of the ammonia gas engine, and then determine the number of groups of injection valves M that need to be put into operation according to the basic ammonia gas injection amount; When M<N, arrange the N groups of injection valves (6) in a circular permutation; starting from the first group, sequentially select M groups of injection valves (6) in the circular permutation to supply ammonia gas. After using the cycle time T; then sequentially start from the next group and sequentially select M groups of injection valves (6) in the circular permutation to supply ammonia gas; thus sequentially and circularly select M groups of injection valves (6) to supply ammonia gas to ensure that each injection valve (6) is rotated for use; When M = N, all the injection valves (6) supply ammonia gas in accordance with the opening sequence.

8. The injection control method of the ammonia engine system according to claim 7, characterized in that: The number of the injection valves (6) is 6. The opening sequence of the 6 injection valves (6) is 1-5-3-6-2-4, and the opening interval time is t / 6, where t is the pulse period of the work of the injection valve (6). The 6 injection valves (6) are evenly divided into 3 adjacent groups.

9. The injection control method for the ammonia gas engine system according to claim 8, wherein When the ammonia gas engine is in an idle running state or a low load condition, the number of groups of injection valves that need to be put into operation is 1 group; When the ammonia gas engine is in a medium speed and medium to high load condition, the number of groups of injection valves that need to be put into operation is 2 groups; When the ammonia gas intake demand of the operating condition of the ammonia gas engine requires 3 groups of injection valves to provide, then all the injection valves (6) are fully enabled and supply ammonia gas in accordance with the opening sequence.

10. The injection control method of the ammonia engine system according to claim 7, characterized in that: Calibrate the injection pulse width MAP table in advance with the engine speed and intake pressure as independent variables; in actual work, query the injection pulse width MAP table according to the actual speed and intake pressure to obtain the injection pulse width, and control the work of each injection valve (6) according to the injection pulse width.

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