2540results about "Exhaust gas recirculation" patented technology

The invention discloses a mixing valve opening degree control method, device and equipment and a medium, and the method comprises the steps that when a mixing valve is in a transition working condition from full opening to non-full opening, the current mixing valve opening degree and the mixing valve opening degree change rate are obtained; determining the maximum boost pressure, the minimum boost pressure, the current target boost pressure and the current actual boost pressure, and determining a mixing valve opening change rate correction coefficient and locking time based on the maximum boost pressure, the minimum boost pressure, the current target boost pressure and the current actual boost pressure; wherein the locking time refers to the time for keeping the current opening degree of the mixing valve unchanged; after the locking time is over, the mixing valve opening degree change rate is corrected based on the mixing valve opening degree change rate correction coefficient, and the final mixing valve opening degree change rate is obtained; and based on the current mixing valve opening and the final mixing valve opening change rate, the mixing valve control opening is determined. According to the method, the change rate of the opening degree of the mixing valve is controlled and optimized from the angle of improving the boost pressure control precision.

A cooling system for vehicles and a control method thereof improves indoor heating performance and fuel efficiency by controlling a flow rate of a coolant passing through a heater core together with an EGR cooler. A coolant having an increased temperature is first supplied to the heater core side through a flow stagnancy control to rapidly increase the temperature of the coolant flowing in the heater core, thereby improving heating performance. A warm-up feature is improved through an exhaust heat recovery function by a heat exchange between the exhaust gas and the coolant in the EGR cooler, thereby improving efficiency of fuel.

The invention belongs to the technical field of vehicles, and discloses an EGR cooler and a vehicle power system.The EGR cooler comprises a pre-cooler and a main cooler, before waste gas enters the main cooler, the waste gas firstly passes through a pre-cooling pipeline in the pre-cooler and exchanges heat with a cooling medium in a pre-cooling flow channel to be pre-cooled, then the waste gas enters the main cooling pipeline to be cooled, and then the waste gas enters the main cooling pipeline to be cooled; when high-temperature waste gas enters the pre-cooling pipeline, the pre-cooling pipeline is heated, due to the fact that the pre-cooler shell and the pre-cooling pipeline are integrally cast and formed, the structural strength between the pre-cooler shell and the pre-cooling pipeline is high, the pre-cooler shell and the pre-cooling pipeline cannot crack due to stress, in addition, the waste gas entering the main cooling pipeline is pre-cooled, stress generated at the connecting position of the main cooling pipeline is small, and the pre-cooling pipeline is not prone to cracking. And the joint of the main cooling pipeline can be prevented from cracking.

The invention relates to the technical field of exhaust gas recirculation of engines, in particular to an engine, a vehicle and an EGR exhaust gas flow control method. The engine comprises an air cylinder, at least two exhaust manifold branches, an EGR system and a control system, the air cylinder comprises an air inlet and at least two exhaust ports, the air inlet is communicated with an air inlet manifold, the number of the exhaust manifold branches is the same as that of the exhaust ports, inlets of the exhaust manifold branches are communicated with the exhaust ports in a one-to-one correspondence mode, the EGR system comprises at least two EGR channels, and the EGR channels are communicated with the exhaust ports in a one-to-one correspondence mode. Inlets of the EGR channels communicate with the exhaust manifold branches in a one-to-one correspondence mode, an outlet of each EGR channel communicates with the intake manifold, each EGR channel is connected with the control system, and the control system is used for controlling the waste gas flow of the at least two EGR channels. According to the implementation mode, due to the fact that the opening degree of each EGR channel can be accurately controlled, the engine can achieve optimal EGR rate control under the small exhaust gas flow and the large exhaust gas flow, and therefore the fuel economy and emission consistency of the engine are improved.

The invention discloses an engine control method and a related device, and relates to the field of engines, an engine is provided with two EGR branches which are respectively connected with a large turbine runner and a small turbine runner, an engine controller determines a corresponding target EGR rate based on target performance parameters of the engine, a small runner EGR valve is controlled to be opened, and the small runner EGR valve is controlled to be closed. If the target EGR rate can be reached by only opening the small-flow-channel EGR valve, outputting a corresponding first target small-flow-channel EGR valve opening degree, and if the opening degree of the small-flow-channel EGR valve reaches the first set maximum opening degree and the corresponding EGR rate does not reach the target EGR rate, controlling the large-flow-channel EGR valve to be opened to reach the target EGR rate, and outputting a corresponding second target small-flow-channel EGR valve opening degree and a target large-flow-channel EGR valve opening degree. Two-way EGR gas taking is achieved by controlling the opening degree of the two-way EGR valve, the EGR rate is improved, meanwhile, the pumping loss and the rotating speed of the supercharger are reduced, and therefore oil consumption and NOx emission are reduced.

An exhaust gas recirculation mixer according to certain embodiments is operable to receive a first fluid via a first fluid intake and to receive a second fluid via a second fluid intake. One of the first fluid or the second fluid comprises air, and the other of the first fluid or the second fluid comprises exhaust gas. The exhaust gas recirculation mixer generally includes a plurality of mixing passages and a plurality of multi-path nozzles. Each mixing passage includes a corresponding and respective throat. Each multi-path nozzle generally includes an outer nozzle fluidically connected to the first fluid intake, and an inner nozzle fluidically connected to the second fluid intake. The inner nozzle is nested within the outer nozzle and projects into the throat of a corresponding and respective mixing passage.

The invention relates to an EGR control method, a vehicle-mounted terminal and a vehicle. The method comprises the steps that the vehicle is powered on, and whether EGR enabling conditions are met or not is judged; if yes, the opening degree of an EGR valve is controlled according to the first calibration data, and the cooling liquid flow of an EGR cooler is controlled according to the second calibration data; if not, the EGR valve is kept closed; when the EGR enabling condition is met, a first difference value between the gas outlet temperature of an EGR cooler under the current engine working condition and the target EGR gas temperature corresponding to the working condition in third calibration data is calculated; and if the first difference value is larger than 0, the cooling liquid flow of the EGR cooler is increased till the first difference value falls into the first temperature difference range. According to the EGR control method, generation of condensate water in the EGR valve can be reduced.

The invention provides a control device for an intercooling bypass and an EGR cooler bypass in an engine, and belongs to the technical field of engines, the control device comprises a multi-way butterfly valve provided with at least three airflow channels, and the input end of the multi-way butterfly valve is communicated with a supercharger; the EGR cooler is arranged on the EGR cooling branch, one end of the EGR cooling branch communicates with the EGR loop, and the other end of the EGR cooling branch communicates with the intake manifold; one end of the EGR bypass branch communicates with the EGR loop through a first airflow channel of the multi-way butterfly valve, and the other end of the EGR bypass branch communicates with the EGR cooling branch and is located between the EGR cooler and the intake manifold; one end of the inter-cooling bypass branch is communicated with the intake manifold, and the other end of the inter-cooling bypass branch is communicated with a second airflow channel of the multi-way butterfly valve; and one end of the intercooler communicates with the intake manifold, and the other end of the intercooler communicates with the third airflow channel of the multi-way butterfly valve. By additionally arranging the multi-way butterfly valve, the purpose of adjusting the cooling strategies of the EGR system and the intercooling system at the same time is achieved.

The invention belongs to the technical field of engine gas supply, and discloses an engine gas supply system and an EGR rate determining method.The engine gas supply system comprises an engine, a gas inlet pipe, an exhaust pipe and an EGR assembly, the engine is provided with multiple cylinders, the gas inlet pipe communicates with the gas inlet ends of the multiple cylinders, and the exhaust pipe communicates with the exhaust ends of the multiple cylinders; the EGR assembly comprises a gas storage tank, a main control valve, an EGR main pipe and a plurality of EGR branch pipes, the first end of the EGR main pipe is communicated with the exhaust pipe through the main control valve, the second end of the EGR main pipe is communicated with the gas storage tank, the gas storage tank is communicated with the gas inlet ends of the cylinders through the EGR branch pipes, and each EGR branch pipe is provided with an EGR control valve; the EGR rate determination method is applied to the engine gas supply system. According to the air supply system of the engine, it is ensured that the pressure of waste gas supplied to the air cylinders of the engine subsequently does not fluctuate, and the uniformity of the EGR rate of each air cylinder is ensured.

The invention relates to the technical field of engines, in particular to an EGR cooler and an engine system.The EGR cooler comprises a cooler shell, the cooler shell is provided with a through hollow cavity, and an air inlet, an air outlet, a water inlet and a water outlet are formed in the cooler shell; at least one group of Tesla valves are arranged in the hollow cavity along the extension direction of the cooler shell, the Tesla valves are provided with gas flow channels, the gas flow channels are communicated with the gas inlet and the gas outlet, cooling water flow channels are formed between the Tesla valves and the cooler shell, and the cooling water flow channels are communicated with the gas inlet and the gas outlet. The cooling water flow channel is communicated with the water inlet and the water outlet; and the cooling water circulation assembly is communicated with the water inlet and the water outlet in series. According to the EGR cooler, the integration degree of the EGR cooler can be improved, occupied space is reduced, and therefore arrangement is facilitated; and meanwhile, the waste gas cooling effect can be guaranteed.

An engine system includes: a reformer including a catalyst for decomposing fuel into hydrogen and configured to reform the fuel to generate a reformed gas containing the hydrogen; a temperature detection unit configured to detect a temperature of the reformed gas; a rotation fluctuation detection unit configured to detect an amount of rotation fluctuation of an engine; and a deterioration detection unit configured to detect whether reforming performance of the catalyst of the reformer is deteriorated based on detection values of the temperature detection unit and the rotation fluctuation detection unit, wherein when, in an idling period of the engine, the amount of rotation fluctuation of the engine is equal to or greater than a second threshold in a state where the temperature of the reformed gas is equal to or higher than a first threshold, the deterioration detection unit determines that the reforming performance of the catalyst is deteriorated.

The invention discloses an engine EGR system, a control method and a vehicle. The engine EGR system comprises a turbocharger, a first valve, an electric compressor, an intercooler, an EGR cooler and at least one air cylinder. The exhaust end of the air compression assembly is connected with the first end of the intercooler, and the second end of the intercooler is connected with the air inlet end of the air cylinder. The first end of the first valve is connected with the exhaust end of the air compression assembly, the second end of the first valve is connected with the second end of the EGR cooler, the third end of the first valve is connected with the first end of the electric air compressor, and the second end of the electric air compressor is connected with the intercooler; air enters through the air inlet end of the air compression assembly, and the first valve controls the intervention condition of the electric air compressor by adjusting the opening degree of the first valve. Air passes through the intercooler and the air cylinder to generate waste gas, and at least part of the waste gas flows into the turbine assembly and is exhausted. According to the engine EGR system provided by the invention, the intervention condition of the electric gas compressor is controlled through the action of the first valve, so that the purpose of adapting to multiple working conditions and multiple scenes is achieved.

The utility model provides an automobile exhaust selector valve and a hybrid engine, which comprise a pipe shaped like a Chinese character'bu ', a linkage valve core and a control actuating mechanism, the pipe shaped like the Chinese character'bu' is provided with a main flow channel and an auxiliary flow channel, the auxiliary flow channel is arranged on the side of the main flow channel and is communicated with the main flow channel, and the linkage valve core is arranged on the pipe shaped like the Chinese character'bu '. The linkage valve element is rotatably arranged in the main flow channel and used for adjusting the communication sectional area of the main flow channel and the auxiliary flow channel, the control execution mechanism is used for driving the linkage valve element to rotate and be positioned in the main flow channel, the linkage valve element comprises a main valve plate and an auxiliary valve plate, and the auxiliary valve plate is fixedly arranged on the main valve plate. The main valve plate is rotatably arranged in the main flow channel and used for adjusting the opening range of the main flow channel, and the auxiliary valve plate is used for synchronously moving along with the main valve plate so as to synchronously adjust the opening range of the auxiliary flow channel when the main valve plate moves. The actuating mechanism is controlled to drive the main valve plate to rotate, and the main valve plate can drive the auxiliary valve plate to move together to form linkage and positioning when rotating, so that the relative gas output of the main flow channel and the auxiliary flow channel is accurately controlled.

The invention discloses an anti-icing method for an engine air inlet system, the engine air inlet system and a vehicle, and belongs to the technical field of engines. According to the anti-icing method for the engine air inlet system, the engine air inlet system and the vehicle, when the engine is in low-temperature cold start, the water vapor content in the engine air inlet system is reduced by reducing the torque of the engine; and / or the speed of the vehicle is reduced, so that the situation that the temperature of cooling liquid in a water jacket of the engine rises too slowly due to the fact that the vehicle purges the engine windward is avoided; when the temperature of the cooling liquid in the water jacket of the engine is low, adverse factors causing icing of an air inlet system of the engine are weakened, and the icing risk is reduced; when the temperature of the engine is too low, the temperature of the cooling liquid in the water jacket of the engine is high, the EGR mixer and the air inlet mixer are heated through waste heat of the engine, the problem that water separated out of high-temperature waste gas is frozen is solved, the purpose of preventing freezing can be achieved, cost is low, and system robustness is high.

The invention discloses a detection and calibration device and method for clamping stagnation of an EGR (Exhaust Gas Recirculation) valve, and the method comprises the steps: firstly, dismounting the EGR valve of an engine, and dismounting the EGR valve into an actuator and a valve body; the first component is installed on the original installation face, in butt joint with the valve body, of the actuator, and the distance between the plane at one end of a push rod of the actuator and the installation plane of the actuator is adjusted and fixed to any numerical value; the second component is installed on the original installation face, where the actuator is installed, of the valve body, and the distance between the end face, connected with the bowl body, of the adjusting bolt unit and the installation face of the valve body is adjusted to be equal to the distance between the plane at one end of a push rod of the actuator and the installation plane of the actuator; and then detection is carried out according to an EGR valve clamping stagnation fault test method. According to the detection and calibration device and method for clamping stagnation of the EGR valve, the EGR valve cannot be damaged in the EGR valve detection process, and clamping stagnation faults can be set randomly in the stroke of the EGR valve.

A power system includes an intake arrangement and a compression ignition engine including piston-cylinder sets. Each piston-cylinder set includes: a cylinder; a piston positioned within the cylinder to form a combustion chamber in between; an intake valve configured to open and close the intake port; an exhaust valve configured to open and close the exhaust port; and a fuel injector. During an exhaust stroke, the exhaust valve is opened to enable exhaust gas to flow out; during an initial portion of an intake stroke, the intake valve is opened to enable the intake air to flow into the combustion chamber, and during a further portion of the intake stroke, the intake valve is closed and the exhaust valve is opened to enable a portion of the exhaust gas to flow back into the combustion chamber in order to create thermally stratified layers of intake gas and exhaust gas.

The invention relates to the technical field of hybrid power vehicles, in particular to a water bleeding and fire catching pre-control method and device for a vehicle exhaust gas recirculation system, and the method comprises the steps that in the operation process of a hybrid power engine of a vehicle, the water bleeding amount caused by EGR condensation under the normal pressure state is obtained; the temperature difference and the pressure difference before and after the intercooler are detected, and the saturated water content of the pressurized mixed gas is calculated in combination with the actual saturated vapor pressure, so that the water precipitation amount in the intake manifold is obtained; based on the temperature difference and the pressure difference, the water precipitation grade of the water precipitation amount in the intake manifold is determined, and according to the water precipitation amount, the water precipitation grade and the water precipitation amount in the intake manifold, an active intervention action of a hybrid vehicle control unit of the vehicle for water precipitation fire pre-control is generated. Therefore, the problems that in the related technology, due to the fact that formation of condensate water is reduced or the EGR rate is reduced to improve the combustion stability of an engine by controlling an EGR valve, the engine is prone to misfire, and the use requirement of a user in an actual scene is difficult to meet are solved.

The invention discloses a method for actively regulating and controlling the temperature of an exhaust pipe under the sliding working condition of an engine, and relates to the engine control technology, the current working condition of the engine is recognized, and if the current working condition is the sliding working condition, an exhaust temperature increasing regulation and control mode is started; according to the exhaust temperature increasing regulation and control mode, a temperature rise demand target is calculated according to the temperature difference value between the current exhaust temperature of an exhaust pipe of the engine and the set target exhaust temperature, and a temperature rise control strategy is selected according to the temperature rise demand target and executed. The invention further discloses a system for actively regulating and controlling the temperature of the exhaust pipe under the engine sliding working condition. The exhaust temperature in the sliding process is increased, the cold and hot temperature difference of the exhaust pipe is reduced, and therefore the reliability of the exhaust pipe is improved.

According to certain embodiments, a method generally involves mixing exhaust gas and air in an exhaust gas recirculation mixer. The method includes directing exhaust gas from the engine to the mixing tube along a first flow path, and directing air to the mixing tube along a second flow path. One of the first flow path or the second flow path is an outer flow path, and the other of the first flow path or the second flow path is an inner flow path surrounded by the outer flow path. The first flow path and the second flow path merge within the throat of the mixing tube such that the exhaust gas and the air mix within the mixing tube to provide a mixture of the exhaust gas and the air.

When EGR gases are introduced into the intake passage through EGR passage, the control device determines whether or not the condensed water is generated in the merging portion of the intake passage, which is the portion to which EGR passage is connected. The control device determines whether or not the internal combustion engine is in a high-load operation based on the engine speed and the engine torque. The control device determines that the condensed water is generated in the merging portion of the intake passage, and reduces the amount of the condensed water collected by the collection device when the internal combustion engine is determined to be in a high-load operation.

A system, method, and apparatus for zero or low NOx emissions during a certain operating period are provided. A system can include an aftertreatment system including a catalyst. The system can include a pump coupled to at least an intake of an engine and an exhaust of the engine. The system can include a heater positioned downstream of the engine. The system can further include a controller coupled to at least the aftertreatment system. the pump, and the heater. During a warmup period for the aftertreatment system. the controller is configured to maintain the engine in an off state. initiate the heater to increase a temperature of the aftertreatment system while the engine is in the off state. and control the pump to generate an airflow directed from the intake to the heater to increase the temperature of the aftertreatment system.

The invention relates to the technical field of vehicle exhaust gas recirculation, in particular to a double-valve-plate EGR valve and a vehicle. A first channel and a second channel are arranged in the valve seat in a spaced mode and communicate with each other, the valve rod sequentially penetrates through the first valve plate and the second valve plate, the first valve plate is used for opening or closing the first channel, the second valve plate is used for opening or closing the second channel, and the valve rod is arranged in the valve seat in a sliding mode. When the valve rod is located at the first position, the first valve plate closes the first channel, the second valve plate closes the second channel, when the valve rod is located at the second position, the first valve plate opens the first channel, the second valve plate closes the second channel, and when the valve rod is located at the third position, the first valve plate opens the first channel. The second valve plate opens the second channel. Compared with the prior art, the double-valve-plate EGR valve has the advantages that the first channel and the second channel can be selectively controlled to be opened according to different working conditions, the control precision is improved, the leakage rate is reduced, and the universality is improved.

The present invention discloses a closed-loop EGR flow control system and control method for a natural gas engine. The control system includes: a controller for determining an EGR demand flow rate based on actual engine operating conditions; a controller for obtaining the pressure of an air and gas mixture detected by an intake pressure sensor; or, alternatively, for determining the pressure of an air and gas mixture based on the EGR demand flow rate, a threshold flow rate, the maximum opening of an EGR valve, the actual opening of the EGR valve, the gas flow rate, and the fresh air flow rate; a controller for determining an actual EGR flow rate based on the obtained pressure of the air and gas mixture, the partial pressure of gases in the cylinder, the pressure-to-flow conversion slope, the gas flow rate, and the fresh air flow rate; a controller for determining an EGR flow rate correction value based on the obtained actual EGR flow rate and the EGR demand flow rate; and a controller for adjusting the EGR valve opening based on the EGR flow rate correction value so that the actual EGR flow rate matches the EGR demand flow rate, thereby achieving closed-loop control of the EGR flow rate. The present invention can achieve precise control of the EGR flow rate in two ways.

The present invention relates to a housing for a compressor, the housing accommodating an impeller and allowing the impeller to rotate relative to the housing, comprising: a first intake passage guiding air in a first guiding direction; a second intake passage extending at least partially circumferentially along the housing and guiding exhaust gas in a second guiding direction, the second intake passage comprising an inlet section and an opposite outlet section, and the outlet section being positioned radially inward of the inlet section, a cross-sectional ratio between an inlet cross-sectional area of the inlet section and an outlet cross-sectional area of the outlet section is between 2 and 10, and at the outlet section, a first angle formed by the second guide direction and the radial direction is in the range of 45 to 90 degrees. The shell enables mixed gas formed by air and waste gas to generate circumferential speed, the erosion rate of the blades is reduced, and the impeller does not need to be coated with a coating. In addition, the invention also relates to a compressor and an exhaust gas recirculation system.

The invention relates to a crankcase forced ventilation system and a control method thereof, a supercharged engine and a vehicle, and belongs to the technical field of engines. The crankcase forced ventilation system comprises an air inlet system of an engine, a first ventilation pipeline and a second ventilation pipeline, the air inlet system comprises an air filter, a supercharger, a throttle valve and an air inlet manifold which are sequentially communicated through pipelines, the air inlet system is communicated with an air cylinder of the engine through the air inlet manifold, and the first end of the first ventilation pipeline is communicated with a crankcase; the first ventilation pipeline is provided with a first crankcase forced ventilation PCV valve, the second ventilation pipeline is provided with a second crankcase forced ventilation PCV valve, the first end of the second ventilation pipeline is communicated with the crankcase, the second end of the second ventilation pipeline is communicated with a pipeline connected between the supercharger and the air filter, and the second ventilation pipeline is provided with a vacuum pump. When the engine is in various working conditions, waste gas in the crankcase can be smoothly circulated while the pressure in the crankcase is small.

An anti-clamping stagnation EGR valve with a sealing structure is characterized in that a valve rod sub-assembly is arranged in a valve body, the valve rod sub-assembly comprises a valve rod body, a valve rod channel is formed in the valve body, the valve rod body is located in the valve rod channel, a flexible protective sleeve assembly is arranged on the valve rod body, and the flexible protective sleeve assembly comprises an inner protective sleeve, a rubber sleeve body and an outer baffle; the valve rod body penetrates through the center of the inner sheath, the center of the rubber sleeve body and the center of the outer baffle, the inner sheath is connected to the inner end of the rubber sleeve body, and the outer baffle is connected to the outer end of the rubber sleeve body. The outer baffle is in interference fit with the valve rod body; a plurality of sealing bulges are formed on the rubber sleeve body; the gap between the inner wall of the valve rod channel and the valve rod body is sealed through the sealing protrusion so that particulate matter / corrosives can be prevented from penetrating through the gap. Waste gas can be prevented from leaking along the valve rod body to the maximum extent, valve body sealing is achieved, a gas channel is isolated, particulate matter or corrosives are prevented from being accumulated in a gap between the valve rod body and the guide sleeve, carbon deposition is reduced, and the service life is prolonged.

The present invention provides a device and method for controlling the intake air temperature of a methanol compression ignition engine, belonging to the field of engine technology. The control device includes: an intercooler disposed on an intercooler circuit, the intercooler circuit being provided with a first valve; an intercooler bypass branch being provided with a second valve; an EGR cooler disposed on the EGR circuit, the EGR circuit being provided with a third valve and a fifth valve; an EGR bypass branch being provided with a fourth valve; and a controller for controlling one of the first and second valves to open and the other to close under cold start conditions or preset low-load conditions, adjusting the opening of the fourth valve based on an intake air temperature target value, and controlling the third and fifth valves to close. By providing an intercooler bypass, the present invention solves the problem that existing methanol compression ignition engines cannot achieve stable cold start ignition, sustained stable ignition, and stable combustion when burning pure methanol fuel in a low-temperature environment.

A Venturi device with a primary flow path and a secondary flow path introduced into the primary flow path, wherein a flow of one or more flowable mediums in the primary flow path and the secondary flow path creates a vortex generating a suction at an inlet of the Venturi device. A particulate burner system can be used to combust fuel emission byproducts by injecting fuel and air into a housing having a bottom plate with a round bottom opening for burners to inject fuel into a combustion chamber and a top plate with a round top opening for exhausting fuel emissions. A thruster system can be used to propel munition for deep earth penetration by using a thruster system having a transfer cone connected to a munition body.

An integration system for use with a turbine, the integration system including an inlet bleed heat (IBH) system, an exhaust gas recirculation (EGR) system, and a controller.

An exhaust gas recirculation mixer according to certain embodiments includes a chamber through which a first fluid is operable to flow in a downstream direction toward a mixing passage. The chamber is fluidically connected with the mixing passage via a first nozzle, and the mixing passage extends along a longitudinal axis defining the downstream direction and an upstream direction opposite the downstream direction. The exhaust gas recirculation mixer further includes a second nozzle and a fuel nozzle. The second nozzle extends into the mixing passage and is configured to direct a second fluid toward the mixing passage. The second nozzle comprises a second nozzle outlet portion circumferentially surrounded by the first nozzle. The fuel nozzle comprises a fuel nozzle outlet portion configured to inject fuel into the chamber in a fuel injection direction, and the fuel nozzle outlet portion is positioned upstream of the first nozzle.