阅读说明：本技术 一种增压汽油机及其调节管路和调节方法 (Supercharged gasoline engine and adjusting pipeline and adjusting method thereof ) 是由 于冠军 梁艳军 王绍明 曾斌 闫岩 王镇 杨芾 杨�嘉 于 2019-09-24 设计创作，主要内容包括：本发明涉及一种增压汽油机及其调节管路和调节方法,其中,增压汽油机的调节管路包括引气管路和设于引气管路的第一调节阀,述第一调节阀与ECU连接,引气管路的一端与三元催化器的催前端连通；当三元催化器的催前端的气体的过量空气系数小于预设值时,ECU控制第一调节阀的开度并通过引气管路向催前端通入空气。在不影响增压器保护以及发动机功率指标的同时,能够保证增压汽油机的三元催化器的处理效率,进而保证该增压汽油机的排放符合标准。(The invention relates to a supercharged gasoline engine and an adjusting pipeline and an adjusting method thereof, wherein the adjusting pipeline of the supercharged gasoline engine comprises an air bleed pipeline and a first adjusting valve arranged on the air bleed pipeline, the first adjusting valve is connected with an ECU, and one end of the air bleed pipeline is communicated with the front end of a three-way catalyst; when the excess air coefficient of the gas at the front end of the three-way catalyst is smaller than a preset value, the ECU controls the opening of the first adjusting valve and introduces air to the front end of the catalyst through the air introducing pipeline. The treatment efficiency of the three-way catalyst of the supercharged gasoline engine can be ensured while the protection of the supercharger and the power index of the engine are not influenced, and the emission of the supercharged gasoline engine is ensured to meet the standard.)

1. The adjusting pipeline of the supercharged gasoline engine is characterized by comprising an air bleed pipeline and a first adjusting valve arranged on the air bleed pipeline, wherein the first adjusting valve is connected with an ECU (40), and one end of the air bleed pipeline is communicated with a catalytic front end (11) of a three-way catalyst (10);

when the excess air coefficient of the gas at the front end (11) of the three-way catalyst (10) is smaller than a preset value, the ECU (40) controls the opening of the first regulating valve and leads the air into the front end (11) through the air-leading pipeline.

2. The regulating circuit according to claim 1, characterized in that the bleed line communicates between the catalytic front end (11) and the post-compression end (23) of the pressure booster (20).

3. The regulating circuit according to claim 2, characterized by further comprising an exhaust line and a second regulating valve provided in said exhaust line, said second regulating valve being connected to said ECU (40), one end of said exhaust line being in communication with said post-compression end (23);

when the excess air ratio is not less than the preset value and a throttle valve (30) of a supercharged gasoline engine is not fully opened, the ECU (40) controls the opening degree of the second regulating valve and exhausts the air of the rear end (23) through the exhaust line.

4. The regulating circuit according to claim 3, characterized in that the exhaust line communicates with the after-pressure end (23) and the after-catalyst end (12) of the three-way catalyst (10).

5. The regulating circuit according to claim 4, characterized in that it comprises a three-way valve (4), a first branch (1) communicating with the pressure rear end (23), a second branch (2) communicating with the pressure front end (11) and a third branch (3) communicating with the pressure rear end (12);

the first branch (1) and the second branch (2) are connected in series through the three-way valve (4) to form the gas guiding pipeline, and the first branch (1) and the third branch (3) are connected in series through the three-way valve (4) to form the gas exhaust pipeline;

the first branch (1) is provided with a regulating valve (5), and the regulating valve (5) forms the first regulating valve and the second regulating valve.

6. The regulating circuit according to claim 5, characterized in that the first branch (1) is provided with a flow detection unit communicating with the ECU (40) for detecting the ventilation of the bleed line and the exhaust line.

7. The regulating circuit according to claim 6, characterized in that the flow detection unit is a differential pressure sensor (6) provided at both ends of the regulating valve (5).

8. The regulating circuit according to claim 5, characterized in that the first branch (1) is provided with a non-return valve (7), the non-return valve (7) having a flow direction from the first branch (1) to the second branch (2) and to the third branch (3).

9. A supercharged gasoline engine, characterized by comprising a three-way catalyst (10), a supercharger (20) and an adjusting pipeline according to any one of claims 1 to 8, wherein the catalytic front end (11) of the three-way catalyst (10) is provided with an oxygen sensor (50).

10. A method for regulating a supercharged gasoline engine is characterized by comprising the following steps:

s1: detecting the oxygen content of the gas at the catalytic front end (11) of the three-way catalyst (10);

s2: calculating an excess air factor from the oxygen content;

s3: when the excess air coefficient is smaller than a preset value, air is supplemented to the front end (11) through an air introducing pipeline, and the supplementary air amount is gradually increased until the excess air coefficient reaches the preset value.

11. The method according to claim 10, characterized in that in step S3, the supply of air to the catalyst front end (11) via a bleed air line means that air from the post-pressure end (23) of the supercharger (20) is introduced into the catalyst front end (11) via the bleed air line.

12. The adjusting method according to claim 10, further comprising, after the step S2, a step S4: when the excess air ratio is not less than a preset value and a throttle valve (30) of the supercharged gasoline engine is not fully opened, air at a rear end (23) of the supercharger is exhausted through an exhaust pipeline, the exhaust air amount is gradually increased, and meanwhile, the opening degree of the throttle valve (30) is increased until the throttle valve (30) is fully opened.

Technical Field

The invention relates to the technical field of vehicles, in particular to a supercharged gasoline engine and an adjusting pipeline and an adjusting method thereof.

Background

At present, the emission and oil consumption regulations of internal combustion engines are getting tighter and tighter, and energy conservation and emission reduction are the mainstream directions for the development of the internal combustion engines.

The mainstream aftertreatment device of the current gasoline engine for the vehicle is a three-way catalyst, but the three-way catalyst can only treat the exhaust gas with lambda (excess air ratio) of which the value is close to 1, and if the lambda deviates from 1 to be too large (such as excessive fuel and enrichment), the treatment efficiency of the three-way catalyst is greatly reduced. Generally, because of the protection of a supercharger, the supercharged gasoline engine generally needs to be enriched at a high speed and under a large load to reduce the exhaust temperature, so that the treatment efficiency of the three-way catalyst is reduced, and the gaseous emission is deteriorated.

The GB6b regulation adds the RDE (actual driving condition) cycle requirement, and under the RDE cycle, the gasoline engine always runs to the enrichment region, and the emission is easy to exceed the standard. A common countermeasure is to reduce the engine external characteristics and to discard the enrichment region, but this also means a reduction in the engine power index.

Therefore, how to ensure the treatment efficiency of the three-way catalyst of the supercharged gasoline engine without influencing the supercharger protection and the engine power index and further ensure that the emission of the supercharged gasoline engine meets the standard is a technical problem to be solved by the technical personnel in the field.

Disclosure of Invention

The invention aims to provide a supercharged gasoline engine, an adjusting pipeline and an adjusting method thereof, which can ensure the treatment efficiency of a three-way catalyst of the supercharged gasoline engine and further ensure that the emission of the supercharged gasoline engine meets the standard while not influencing the protection of a supercharger and the power index of an engine.

In order to solve the technical problem, the invention provides a regulating pipeline of a supercharged gasoline engine, which comprises an air bleed pipeline and a first regulating valve arranged on the air bleed pipeline, wherein the first regulating valve is connected with an ECU (electronic control unit), and one end of the air bleed pipeline is communicated with the front catalytic end of a three-way catalyst; and when the excess air coefficient of the gas at the front end of the three-way catalyst is smaller than a preset value, the ECU controls the opening of the first regulating valve and leads air to the front end of the catalyst through the air-entraining pipeline.

Detecting the oxygen content in the gas at the front end of the catalyst by the oxygen sensor, feeding the detection result of the oxygen content back to the ECU, calculating a numerical value (lambda) of an excess air coefficient according to the oxygen content by the ECU, comparing the calculated result lambda with a preset value, if the lambda is smaller than the preset value, indicating that the air content (oxygen content) in the gas at the front end of the catalyst is insufficient and the fuel is excessive (enriched), opening and adjusting the opening degree of a first adjusting valve by the ECU, supplementing air to the front end of the catalyst through a bleed air pipeline, calculating the lambda according to the oxygen content in the gas at the front end of the catalyst after air is supplemented, comparing the lambda with the preset value, if the lambda reaches the preset value, ending the adjustment, and if the lambda is still smaller than the preset value, increasing the opening degree of the first adjusting valve, calculating the lambda again and comparing the lambda with the preset value until the lambda of the gas at the front end of the catalyst reaches the preset value.

That is to say, when the supercharged gasoline engine is under high speed and heavy load, the lambda of the raw gas at the front end (the waste gas after the turbine of the supercharged gasoline engine is pushed to work) is smaller than the preset value due to the reasons of reducing exhaust temperature by enrichment and the like, namely when the air content of the raw gas is insufficient, air is supplemented into the front end of the supercharged gasoline engine through the air introducing pipeline, the supplemented air and the raw gas are introduced into the three-way catalyst together from the front end of the supercharged gasoline engine, the air content in the gas introduced into the three-way catalyst can be improved, the oxygen sensor detects the oxygen content of the front end in real time, the ECU calculates the lambda of the front end in real time and gradually increases the opening of the first regulating valve until the lambda of the gas at the front end meets the preset value, and then the treatment efficiency of the three-way catalyst can be effectively ensured.

On the basis of the structure of an original supercharged gasoline engine, the adjusting pipeline of the supercharged gasoline engine is simple in structure and convenient to achieve, and can adjust the gas lambda led into the three-way catalyst from the front end to reach the preset value when the gas lambda of the front end is smaller than the preset value by additionally arranging the gas guiding pipeline and the first adjusting valve, so that the treatment efficiency of the three-way catalyst is guaranteed.

Optionally, the bleed air pipeline is communicated with the pressure front end and the pressure rear end of the supercharger.

Optionally, the system further comprises an exhaust pipeline and a second regulating valve arranged on the exhaust pipeline, the second regulating valve is connected with the ECU, and one end of the exhaust pipeline is communicated with the rear end of the pressure sensor; and when the excess air coefficient is not less than the preset value and a throttle valve of the supercharged gasoline engine is not fully opened, the ECU controls the opening degree of the second regulating valve and exhausts air at the rear end of the compressor through the exhaust pipeline.

Optionally, the exhaust pipeline is communicated with the rear end and the rear end of the three-way catalyst.

Optionally, the adjusting pipeline comprises a three-way valve, a first branch communicated with the rear end of the pressure device, a second branch communicated with the front end of the pressure device, and a third branch communicated with the rear end of the pressure device; the first branch and the second branch are connected in series through the three-way valve to form the bleed pipeline, and the first branch and the third branch are connected in series through the three-way valve to form the exhaust pipeline; the first branch is provided with a regulating valve, and the regulating valve forms the first regulating valve and the second regulating valve.

Optionally, the first branch is provided with a flow detection unit in communication with the ECU for detecting the ventilation of the bleed air line and the exhaust line.

Optionally, the flow detection unit is a differential pressure sensor disposed at two ends of the regulating valve.

Optionally, the first branch is provided with a check valve, and the flow direction of the check valve is from the first branch to the second branch and the third branch.

The invention also provides a supercharged gasoline engine which comprises a three-way catalyst, a supercharger and the adjusting pipeline, wherein an oxygen sensor is arranged at the front end of the three-way catalyst.

The technical effect of the supercharged gasoline engine with the adjusting pipeline is similar to that of the adjusting pipeline, and is not repeated herein for saving space.

The invention also provides an adjusting method of the supercharged gasoline engine, which comprises the following steps:

s1: detecting the oxygen content of gas at the front end of the three-way catalyst;

s2: calculating an excess air factor from the oxygen content;

s3: and when the excess air coefficient is smaller than a preset value, supplementing air to the front end of the catalyst through an air entraining pipeline, and gradually increasing the supplemented air quantity until the excess air coefficient reaches the preset value.

When the supercharged gasoline engine is in high speed and heavy load, the lambda of the raw gas (waste gas after the turbine of the supercharged gasoline engine is pushed to work) at the front end is smaller than the preset value due to the reasons of enrichment, reduction of exhaust temperature and the like, namely when the air content of the raw gas is insufficient, air is supplemented into the front end of the supercharged gasoline engine through the air introducing pipeline, the supplemented air and the raw gas are introduced into the three-way catalyst together from the front end of the supercharged gasoline engine, and the air content of the gas introduced into the three-way catalyst can be improved.

Specifically, the oxygen sensor detects the oxygen content of the catalytic front end in real time, calculates the lambda of the gas at the catalytic front end in real time, and gradually increases the supplemented air amount until the lambda of the gas at the catalytic front end meets a preset value, so that the treatment efficiency of the three-way catalyst can be effectively ensured.

Alternatively, in step S3, the supplementing of air to the front end of the catalyst through the bleed air line means introducing air at the rear end of the supercharger into the front end of the catalyst through the bleed air line.

Optionally, step S4 is further included after step S2: when the excess air coefficient is not less than the preset value and the throttle valve of the supercharged gasoline engine is not fully opened, the air at the rear end of the supercharger is discharged through the exhaust pipeline, the discharged air quantity is gradually increased, and meanwhile, the opening degree of the throttle valve is increased until the throttle valve is fully opened.

Drawings

FIG. 1 is a schematic structural diagram of a supercharged gasoline engine provided by an embodiment of the invention;

FIG. 2 is a block flow diagram of a method of regulating a supercharged gasoline engine provided by an embodiment of the present invention;

fig. 3 is a schematic diagram of a regulation of a supercharged gasoline engine according to an embodiment of the present invention.

In the accompanying fig. 1-3, the reference numerals are illustrated as follows:

1-a first branch; 2-a second branch; 3-a third branch; 4-three-way valves; 5-adjusting the valve; 6-differential pressure sensor; 7-a one-way valve; 10-three-way catalyst, 11-catalytic front end, 12-catalytic rear end; 20-supercharger, 21-pressure wheel, 22-turbine, 23-rear end of pressure; 30-a throttle valve; 40-ECU; 50-oxygen sensor.

Detailed Description

In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1-3, fig. 1 is a schematic structural diagram of a supercharged gasoline engine according to an embodiment of the present invention; FIG. 2 is a block flow diagram of a method of regulating a supercharged gasoline engine provided by an embodiment of the present invention; fig. 3 is a schematic diagram of a regulation of a supercharged gasoline engine according to an embodiment of the present invention.

The embodiment of the invention provides a supercharged gasoline engine and an adjusting pipeline thereof, wherein the supercharged gasoline engine comprises a supercharger 20, a three-way catalyst 10 and the adjusting pipeline as shown in figure 1, and an oxygen sensor 50 is arranged at the front end 11 of the three-way catalyst 10.

Specifically, the regulating pipeline of the supercharged gasoline engine comprises an air bleed pipeline and a first regulating valve arranged on the air bleed pipeline, one end of the air bleed pipeline is communicated with the front end 11 of the three-way catalyst 10 and used for supplementing air to the front end 11, and the first regulating valve is connected with the ECU 40.

Herein, the rear end 23 of the supercharger 20 refers to the end of the supercharger 20 facing the pressure wheel 21, i.e., the end after supercharging; the catalyst front end 11 of the three-way catalyst 10 refers to an end before catalyst, that is, an air intake end of the three-way catalyst 10; the catalyst rear end 12 of the three-way catalyst 10 is the catalyzed end, namely the air outlet end of the three-way catalyst 10; the preset value of the excess air factor can be adjusted according to the specific structure, parameters and the like of the supercharged gasoline engine, and the preset value can be a specific numerical value (such as 1) or a numerical range (such as 0.95-1.05), and is not limited specifically herein.

The oxygen sensor 50 is used for detecting the oxygen content of the gas of the front end 11, the oxygen content in the gas of the front end 11 is detected by the oxygen sensor 50, the detection result of the oxygen content is fed back to the ECU40, the ECU40 calculates a value (lambda) of an excess air coefficient according to the oxygen content, the calculated result lambda is compared with a preset value, if the lambda is smaller than the preset value, the air content (oxygen content) in the gas of the front end 11 is insufficient, the fuel is excessive (enriched), at the moment, the ECU40 opens and adjusts the opening degree of the first adjusting valve, air is supplemented into the front end 11 through the air introducing pipe, then the lambda is calculated according to the oxygen content in the gas of the front end 11 after the air is supplemented, the adjustment is finished if the lambda reaches the preset value, if the lambda is still smaller than the preset value, the opening degree of the first adjusting valve is increased, the lambda is calculated again and compared with the preset value, until the lambda of the gas in the catalyst front end 11 reaches a preset value.

That is to say, when the lambda of the raw gas (the exhaust gas after pushing the turbine 22 of the supercharged gasoline engine to do work) of the catalyst front end 11 is smaller than the preset value due to the reasons of enrichment and temperature reduction of the supercharged gasoline engine under high speed and heavy load, that is, when the air content of the raw gas is insufficient, air is supplied to the catalyst front end 11 through the bleed air pipeline, the supplied air and the raw gas are introduced into the three-way catalyst 10 from the catalyst front end 11 together, so that the air content of the gas introduced into the three-way catalyst 10 can be increased, the oxygen sensor 50 detects the oxygen content of the catalyst front end 11 in real time, the ECU40 calculates the lambda of the catalyst front end 11 in real time and gradually increases the opening of the first regulating valve until the lambda of the gas of the catalyst front end 11 meets the preset value, so as to effectively ensure the treatment efficiency of the three-way catalyst 10.

The adjusting pipeline of the supercharged gasoline engine provided by the embodiment is based on the structure of the original supercharged gasoline engine, and can adjust the gas lambda introduced into the three-way catalyst 10 from the front end 11 to reach the preset value only by additionally arranging the gas guiding pipeline and the first adjusting valve when the gas lambda of the front end 11 is smaller than the preset value, so that the treatment efficiency of the three-way catalyst 10 is ensured, and the adjusting pipeline is simple in structure and convenient to realize.

In the above embodiment, the bleed air pipeline is connected to the front end 11 and the rear end 23 of the supercharger 20, that is, the bleed air pipeline is used to introduce the supercharged air into the front end 11, or in this embodiment, the bleed air pipeline may also be used to supplement the external air into the front end 11, and the lambda of the gas in the front end 11 may also be realized.

And when communicating the bleed air pipeline in the pressure rear end 23 of urging front end 11 and booster 20, because the air pressure increase after the pressure boost for the bleed air pipeline is greater than the pressure towards the pressure of urging one side of front end 11 towards the pressure of one side of pressure rear end 23, press rear end 23 promptly and urge front end 11 to have pressure differential, consequently, ECU40 only needs the aperture of adjusting first governing valve, the air after the pressure boost can urge front end 11 one side to flow under the effect of pressure differential, need not to establish driving part such as pump in addition, can simplify overall structure.

When the pressurized gas is introduced into the catalyst tip 11 through the bleed air line, the opening degree of the throttle valve 30 of the supercharged steam turbine needs to be increased appropriately, which reduces the throttle loss and reduces the fuel consumption.

In the above embodiment, the regulating circuit further includes an exhaust line and a second regulating valve provided in the exhaust line, wherein the second regulating valve is connected to the ECU40, and one end of the exhaust line is communicated with the rear end 23 of the supercharger 20 for discharging the supercharged air. Specifically, when the above lambda is not less than the preset value and the throttle valve 30 of the supercharged gasoline engine is not fully opened, the ECU40 controls the opening degree of the second regulator valve and exhausts the gas of the pressure rear end 23 of the supercharger 20 through the exhaust line.

In detail, when the above lambda is not less than the preset value, the processing efficiency of the three-way catalyst 10 can be ensured, at this time, the bleed air line does not need to be operated, and if the throttle valve 30 of the supercharged gasoline engine is fully opened at this time, the exhaust line does not need to be operated, if the throttle valve 30 of the supercharged gasoline engine is not fully opened at this time, the ECU40 can gradually increase the opening degree of the second regulating valve and the opening degree of the throttle valve 30 at the same time, the opening degree of the throttle valve 30 is increased, the intake air amount into the supercharger 20 is increased, and the supercharged air is discharged through the exhaust line, the opening degree of the second regulating valve is increased, the exhaust amount is increased, and the required amount of the supercharged air before the start of exhaust (before the opening degree of the second regulating valve and the opening degree of the throttle valve 30 are increased) and after the start of exhaust (after the opening degree of the second regulating valve and the opening degree of the throttle valve, the increase in the intake air amount and the exhaust gas amount are kept balanced, and the engine can be maintained at the original speed/load until the throttle valve 30 is fully opened. If the rotation speed/load of the engine changes midway, the engine stops, and the working condition of the supercharged gasoline engine is further guaranteed not to be affected.

That is to say, on the structural basis of original pressure boost gasoline engine, only through addding exhaust pipe and second governing valve, can be on the basis of guaranteeing normal work, increase this pressure boost gasoline engine's throttle valve 30's aperture, reduce the throttle loss, reduce the oil consumption, its simple structure, be convenient for realize.

Further, the exhaust pipeline is communicated with the rear pressing end 23 and the rear pressing end 12 of the three-way catalyst 10, namely, the exhaust pipeline discharges the pressurized air and the gas processed by the three-way catalyst 10 together and enters the muffler, so that the gas outlet of the pressurized gasoline engine can be reduced, the change of the original structure is reduced, and the overall structure is simplified.

In the above embodiment, the adjusting line includes a three-way valve 4 and a first branch 1, a second branch 2 and a third branch 3 respectively connected to the three-way valve 4, wherein the first branch 1 and the second branch 2 are connected in series to form the gas guiding line, and the first branch 1 and the third branch 3 are connected in series to form the gas discharging line. That is, the first branch 1 communicates with the transition end 23, the second branch 2 communicates with the catalyst front end 11, and the third branch 3 communicates with the catalyst rear end 12.

Moreover, the first branch 1 is provided with a regulating valve 5, when the first branch 1 is communicated with the second branch 2, the regulating valve 5 is the first regulating valve, when the first branch 1 is communicated with the third branch 3, the regulating valve 5 is the second regulating valve, namely, the air guide pipeline and the exhaust pipeline share the same regulating valve 5 and the first branch 1, so that the whole structure can be simplified, and the regulating pipeline can be conveniently arranged in the supercharged gasoline engine.

In the above embodiment, the first branch 1 is provided with the flow rate monitoring unit for detecting the ventilation amount of the bleed air line and the exhaust line, the flow rate monitoring unit is communicated with the ECU40 and feeds back the detection result thereof to the ECU40, so that the air drawn from the rear end 23 is known, and the assist ECU40 monitors the adjustment of lambda and the adjustment of the opening degree of the throttle valve 30. And the setting of this flow detection unit still is convenient for monitor this regulating circuit, avoids leading the gas system unusual because situations such as oxygen sensor 50 became invalid.

Specifically, when the bleed air pipeline and the exhaust pipeline are two mutually independent pipelines, the bleed air pipeline and the exhaust pipeline can be respectively provided with the flow detection unit, and when the bleed air pipeline and the exhaust pipeline share the first branch 1, the flow detection unit can be arranged on the first branch 1, so that the overall structure is simplified.

Further, the flow rate detecting unit is a differential pressure sensor 6 disposed at both ends of the regulating valve 5, and is configured to detect a differential pressure at both ends of the regulating valve 5, and calculate an air flow rate flowing through the first branch 1 according to the differential pressure. Alternatively, in the present embodiment, the flow rate detection means may be provided so that the differential pressure sensor 6 is more economical than other measurement components such as an air flow meter.

In the above embodiment, the first branch 1 is provided with the check valve 7, and the flow direction of the check valve 7 is from the first branch 1 to the second branch 2 and the third branch 3, so as to prevent the gas urging the front end 11 and the gas urging the rear end 12 from flowing back to the rear end 23.

In addition, an embodiment of the present invention further provides a method for adjusting a supercharged gasoline engine, specifically, as shown in fig. 2, the method for adjusting a supercharged gasoline engine includes the following steps:

s1: the oxygen content of the gas at the catalyst tip 11 of the three-way catalyst 10 is detected.

An oxygen sensor 50 is provided at the catalyst tip 11 of the three-way catalyst 10 for detecting the oxygen content of the gas at the catalyst tip 11, that is, the oxygen content of the gas introduced into the three-way catalyst 10.

S2: the excess air factor is calculated from the above oxygen content.

The oxygen sensor 50 feeds back the oxygen content detected in step S1 to the ECU40, and the ECU40 calculates the current excess air coefficient (lambda) from the oxygen content.

S3: when the excess air factor is smaller than the preset value, air is supplemented to the catalyst front end 11 through the bleed air pipe, and the supplementary air amount is gradually increased until the excess air factor reaches the preset value.

Comparing the lambda obtained in the step S2 with a preset value, if the lambda is smaller than the preset value, it indicates that the air content (oxygen content) in the gas is insufficient and the fuel is excessive (enriched), at this time, air is supplemented to the front end 11, then the lambda is calculated according to the oxygen content in the gas of the front end 11 after the air is supplemented and compared with the preset value, if the lambda reaches the preset value, the adjustment is finished, if the lambda is still smaller than the preset value, the opening of the first regulating valve (i.e., the regulating valve 5) of the bleed air pipeline is increased, and the lambda is calculated again and compared with the preset value until the lambda of the gas of the front end 11 reaches the preset value.

That is, when the boost gasoline engine is in high speed and heavy load, the lambda of the raw gas (the exhaust gas after the turbine 22 of the boost gasoline engine is pushed to do work) in the catalyst front end 11 is smaller than the preset value due to the reasons of enrichment, reduction of exhaust temperature, and the like, that is, when the air content of the raw gas is insufficient, air is supplied to the catalyst front end 11 through the air introducing pipe, and the supplied air and the raw gas are introduced into the three-way catalyst 10 together through the catalyst front end 11, so that the air content in the gas introduced into the three-way catalyst 10 can be increased.

Specifically, the oxygen sensor 50 detects the oxygen content of the catalytic front end 11 in real time, calculates the lambda of the gas of the catalytic front end 11 in real time, and gradually increases the amount of the supplemented air until the lambda of the gas of the catalytic front end 11 meets a preset value, thereby effectively ensuring the treatment efficiency of the three-way catalyst 10.

In the above embodiment, the air supply to the catalyst tip 11 in step S3 means that air at the post-compression end 23 of the supercharger 20 is introduced into the catalyst tip 11 through the bleed air line, that is, the bleed air line is connected to the post-compression end 23 and the catalyst tip 11, and pressurized air can be supplied to the catalyst tip 11. Alternatively, in this embodiment, the air-introducing pipeline may also supplement external air to the catalyst tip 11, and similarly, lambda of the gas in the catalyst tip 11 may be adjusted.

And when communicating the bleed air pipeline in urging the pressure rear end 23 of front end 11 and booster 20, because the air pressure increase after the pressure boost for the bleed air pipeline is greater than the pressure towards urging one side of front end 11 towards the pressure of one side of pressure rear end 23, presses rear end 23 promptly and urges front end 11 to have pressure differential, makes the air after the pressure boost can urge one side of front end 11 to flow under the effect of pressure differential, need not to establish driving part such as pump in addition, can simplify overall structure.

When the pressurized gas is introduced into the catalyst tip 11 through the bleed air line, the opening degree of the throttle valve 30 of the supercharged steam turbine needs to be increased appropriately, which reduces the throttle loss and reduces the fuel consumption.

In the above embodiment, as shown in fig. 2, after step S2, S4 is further included: when the excess air ratio is not less than the preset value and the throttle valve 30 of the supercharged gasoline engine is not fully opened, the air at the rear end 23 of the supercharger is discharged through the exhaust line, the discharged air amount is gradually increased and simultaneously the opening degree of the throttle valve 30 is increased until the throttle valve 30 is fully opened.

In detail, when the lambda is not less than the preset value, the treatment efficiency of the three-way catalyst 10 can be ensured, the bleed air line does not need to work, and at this time, if the throttle valve 30 of the supercharged gasoline engine is fully opened, the exhaust pipeline does not need to work, if the throttle valve 30 of the supercharged gasoline engine is not fully opened at the moment, the amount of exhaust gas of the exhaust line (the opening degree of the second regulating valve 5, that is, the opening degree of the regulating valve 5) and the opening degree of the throttle valve 30 can be gradually increased at the same time, so that the amount of intake air entering the supercharger 20 is increased, while the amount of exhaust gas of the supercharged air is increased through the exhaust line, and the required air amount of the supercharged gasoline engine before and after the start of exhaust is unchanged, therefore, by adjusting the opening of the throttle valve 30 and the opening of the regulating valve 5, the increase of the intake air amount and the balance of the exhaust air amount are maintained, and the engine can be maintained at the original speed/load until the throttle valve 30 is fully opened. If the rotation speed/load of the engine changes midway, the engine stops, and the working condition of the supercharged gasoline engine is further guaranteed not to be affected. And the opening degree of the throttle valve 30 of the supercharged gasoline engine is increased, so that the throttling loss can be reduced, and the oil consumption is reduced.

Referring to fig. 3, under the same condition, lambda of the gas at the catalyst front end 11 is detected and calculated in real time, when lambda is smaller than a preset value, the air quantity of the gas at the catalyst front end 11 of the three-way catalyst 10 in the supercharged gasoline engine is adjusted through the bleed air pipeline (the first branch 1 and the second branch 2 are communicated) so that lambda of the catalyst front end 11 reaches (is not smaller than) the preset value to ensure the treatment efficiency of the three-way catalyst 10, then the adjustment is stopped (the opening degree of the adjusting valve 5 is kept unchanged), when the condition changes, lambda of the gas at the catalyst front end 11 is detected and calculated again, and when lambda is smaller than the preset value, the gas is supplemented to the catalyst front end 11 through the bleed air pipeline again according to the above method.

If lambda is not less than the preset value and the regulating valve 5 is in a closed state (i.e. the make-up air adjustment is not performed on the front end 11), at this time, if the throttle valve 30 is fully opened, the regulating valve 5 is closed without any adjustment, if the throttle valve 30 is not fully opened, the air of the rear end 23 of the supercharger 20 is exhausted through the exhaust pipeline (the first branch 1 and the third branch 3 are communicated), meanwhile, the adjustment is stopped when the opening degree of the throttle valve 30 is increased until the throttle valve 30 is fully opened, the opening degree of the regulating valve 5 is kept unchanged, the opening degree of the throttle valve 30 is increased, the throttling loss can be reduced, the fuel consumption can be reduced, whether the original rotating speed/load of the engine can be maintained or not is observed while the opening degree of the regulating valve 5 and the opening degree of the throttle valve 30 are gradually increased, and if the critical value of the original rotating.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and these modifications and improvements should also be considered as the protection scope of the present invention.