106 results about "Exhaust gas sensor" patented technology

The invention discloses an energy-saving dual-fuel heat accumulating type burner usage monitoring control method and system, and relates to the technical field of control and regulation, the energy-saving dual-fuel heat accumulating type burner usage monitoring control system comprises an MEMS multi-parameter sensing array, a tail gas sensor array and a distributed optical fiber temperature sensing module which are deployed in parallel; millisecond-level fuel flow and air flow adjustment is achieved through inner ring flame tensor feedback control, and second-level fuel ratio adjustment is achieved through inner ring tail gas component closed-loop self-adaptive adjustment; and the heat storage regeneration cycle, ash removal triggering and low-speed fuel and air scheduling are achieved through outer ring model predictive control scheduling. The invention provides a multi-layer closed-loop self-adaptive monitoring control method based on flame tensor, tail gas components and a temperature field, and model prediction control is introduced to carry out overall scheduling on a heat storage-combustion coupling process, so that dynamic self-adaption of a fuel ratio, online prediction of heat storage body scaling and multi-time scale coupling optimization are realized.

In a method for adjusting a vehicle parameter, where the vehicle is equipped with an exhaust gas sensor, an exhaust gas sensor signal is received. Based on this signal, a parameter representative of the vehicle's air-fuel ratio is determined. Depending on this parameter, it is then determined whether a transition from a superstoichiometric to a substoichiometric air-fuel mixture, or from a substoichiometric to a superstoichiometric air-fuel mixture, is imminent. If a transition is imminent, the current value of the parameter is adjusted until a predefined termination condition is met. The current parameter value is then transmitted.

An engine to be mounted on a straddle-type vehicle. The engine includes a cylinder and a cylinder head stacked on an upper portion of a crank case, an exhaust pipe extending from the cylinder head and passing through a lateral side of the cylinder, an exhaust gas sensor attached to the exhaust pipe, on the lateral side of the cylinder, and a radiator positioned in front of the cylinder head. The exhaust gas sensor is covered by the radiator from a front side.

The present invention relates to a method and an exhaust gas sensor for determining a corrected nitrogen oxide content in the exhaust gas of an internal combustion engine. The exhaust gas sensor (10) comprises a main body (12), a measuring cavity (40) arranged in the main body (12), in which a measuring electrode (44) is arranged, an exhaust gas electrode (22) exposed to the exhaust gas, which forms an amperometric measuring cell with the measuring electrode (44), and a reference cavity (50) connected to the ambient air, in which a reference electrode (52) is arranged.The method according to the invention comprises applying a measuring current (IP2) to the measuring electrode (44) such that a measuring voltage (V2) developing between the measuring electrode (44) and the reference electrode (52) is maintained at a predetermined first setpoint value, determining a nitrogen oxide content at least partially on the basis of the measuring current (IP2) applied to the measuring electrode (44), determining the electrical impedance of the amperometric measuring cell and determining a corrected nitrogen oxide content at least partially on the basis of the determined nitrogen oxide content and at least partially on the basis of the determined electrical impedance of the amperometric measuring cell.

The method according to the invention for the on-board determination of pollutant emission masses of an internal combustion engine (1) with an exhaust gas aftertreatment device (2) is carried out by executing program instructions of the computer program product (20) according to the invention by means of an electronic control device (7) paired with the internal combustion engine (1) and / or the exhaust gas aftertreatment device (2). Sensor signal values (AS-Sig) provided by an exhaust gas sensor (6c) are detected, pollutant emission values are continuously determined on the basis thereof, and the pollutant emission masses are calculated on the basis of the pollutant emission values during the operation of the internal combustion engine (1). At the same time, the determined pollutant emission values are combined into emission value groups, according to operating parameter ranges of the internal combustion engine (1) and / or of the exhaust gas aftertreatment device (2), and stored in an electronic memory device (7b) of the electronic control device (7) according to the invention, and, on the basis thereof, respective pollutant emission substitute values corresponding to the corresponding operating parameter ranges are determined. The pollutant emission substitute values are used as substitutes in order to determine the pollutant emission masses during operation when temporarily no sensor signal values or only implausible sensor signal values (AS-Sig) are available, and thus no usable current pollutant emission values are available.

Method for heating an exhaust gas sensor (26) in the exhaust system (20) of an internal combustion engine (10), wherein an electrically heated catalyst (24) is arranged in the exhaust system (20) and an exhaust gas sensor (26) is arranged upstream of the electrically heated catalyst (24) and is spaced apart from the electrically heated catalyst (24), wherein the electrically heated catalyst is heated by an electric heating element and the waste heat of the electrically heated catalyst (24) is used to heat the exhaust gas sensor (26) to its release temperature (T) by means of heat conduction via a thermal bridge (28) made of copper or a copper alloy. F ) to heat up.

To provide an exhaust muffler for a vehicle capable of suppressing influence of assembly errors to mount an exhaust gas sensor.SOLUTION: An exhaust muffler 20 for a vehicle of the present disclosure comprises: an inner cylinder 32 in which a silencing space SP is formed; an outer cylinder 34 constituting an outer shell of the muffler 20; a pipe member 51 that is arranged in the silencing space SP, and through which exhaust gas G flows; a sensor 84 that detects a state of the exhaust gas G flowing through the pipe member 51; and a blockage body 88 that is arranged around the sensor 84, and blocks the outward flow of gas in the silencing space SP. The blockage body 88 has a pipe side connection portion 100 connected to the pipe member 51, and an outer cylinder side connection portion 102 connected to the outer cylinder 34.SELECTED DRAWING: Figure 4

The invention relates to a method for diagnosing an exhaust gas sensor (20), in particular a wideband lambda sensor, by means of an evaluation and control unit (10), wherein according to the method: - the sum (Us) of the first voltage variable (U1G) and the second voltage variable (U2G) is formed and it is inferred that the first supply line (41) is interrupted if the sum (Us) of a first voltage variable (U1G) and a second voltage variable (U2G) is greater than a threshold value, and / or - the difference (UD) between the first voltage variable (U1G) and the second voltage variable (U2G) is formed and a resistance value (R1) of the first electrical resistance element (21) and / or a temperature of the exhaust gas sensor (20) is inferred from the difference (UD) between the first voltage variable (U1G) and the second voltage variable (U2G).

In a method for adapting a characteristic variable of a vehicle, the vehicle having an exhaust gas sensor, an exhaust gas sensor signal of the exhaust gas sensor is received. A characteristic variable which is representative of a combustion air ratio of the vehicle is determined in dependence on the exhaust gas sensor signal. In dependence on the characteristic variable, it is determined whether a transition from a superstoichiometric air-fuel mixture to a substoichiometric air-fuel mixture or a transition from a substoichiometric air-fuel mixture to a superstoichiometric air-fuel mixture is imminent. If a transition is imminent, a current value of the characteristic variable is adapted until a predefined termination condition is met. The actual value of the characteristic variable is transmitted.

An exhaust device is disclosed, including: an exhaust chamber 65 disposed to overlap with an internal combustion engine 3 in a top view; an exhaust pipe 61, which passes below the internal combustion engine from an exhaust port 36 of the internal combustion engine, and which includes an opening portion 61c in the exhaust chamber; a catalyst holding pipe 80, which is held in the exhaust pipe, at least a part of which is disposed in the exhaust chamber, and which is filled with a catalyst 8; and an exhaust gas sensor 91 disposed on a sensor attachment boss portion 93, which is provided on the exhaust pipe so as to penetrate into a rear exhaust pipe 61b and the exhaust chamber, the rear exhaust pipe 61b constituting the exhaust pipe, being stored in the exhaust chamber, and holding the catalyst holding pipe. Thus, in providing the exhaust gas sensor at the front and the rear of the catalyst in the exhaust pipe in order to appropriately make a degradation diagnosis of the catalyst for exhaust gas treatment, detection accuracy of the exhaust gas sensor can be improved, while a length in a front-rear direction of the exhaust passage is made compact. Emission improvement is achieved, and contribution to mitigating or reducing the influence on climate change is made, accordingly.

To inexpensively measure a Nox concentration in the atmosphere within a predetermined region.SOLUTION: A measurement system includes: a vehicle 2 having a motor 11 that generates driving force, an engine 12 driven through combustion or driven in a non-combustion state by using the driving force applied from the motor 11, a catalyst that performs purification while activated, an exhaust gas sensor 15 that acquires a state of gas in an exhaust pipe, a position measurement section 16 that acquires positional information, and a transmission section 17 that transmits information on the state of the gas and the positional information; and a server 3 that processes the information received from the vehicle 2. When the motor 11 drives the engine 12 in the non-combustion state and the catalyst 13 is in the inactivate state, the vehicle 2 acquires information on gas flowing in the exhaust pipe by using the exhaust gas sensor 15, acquires the positional information from the position measurement section 16 and transmits the acquired information to the server 3. The server 3 calculates a state of the atmosphere within a predetermined region where the vehicle 2 is traveling by using the information received from the vehicle 2.SELECTED DRAWING: Figure 1

The invention discloses a dew point control method and system for an exhaust gas sensor and a vehicle, and relates to the technical field of automobile emission control. The method provided by the invention comprises the following steps: when the internal combustion engine enters a shutdown stage from an operation stage, selectively executing a control action based on a dew point passing state of an exhaust gas sensor before shutdown: if the dew point passing state is not completed, determining a heat compensation value for subsequent heating; if the dew point passing is completed, shutdown heating is carried out on the sensor in the shutdown stage for heat preservation, physical parameters indicating the condensation risk are monitored, and when the parameters meet reset conditions, the dew point passing state is reset to be uncompleted. By introducing the dynamic control logic combining heat compensation, shutdown heat preservation and risk reset across the start-stop cycle, the waste gas sensor can be effectively prevented from being damaged due to condensation under various working conditions, the reliability of the emission system is remarkably improved, and the service life of the sensor is remarkably prolonged.

This invention provides a comprehensive detection device and method for automotive exhaust pollutants, relating to the field of air pollution detection technology. The comprehensive detection device includes an outer cylinder and an exhaust gas sensor. A support unit is located inside the outer cylinder, and the support unit has rotating blades and a cleaning component. When exhaust gas with a temperature lower than a preset value is introduced into the outer cylinder, it drives the blades and cleaning component to rotate, allowing the cleaning component to contact the surface of the exhaust gas sensor and move relative to it. This cleans the pollutants adhering to the surface of the exhaust gas sensor even during the cold start phase of the vehicle, ensuring the operational stability of the exhaust gas sensor and the accuracy of the detection data. When exhaust gas with a temperature greater than or equal to the preset value is introduced into the outer cylinder, the blades and cleaning component overlap with the support unit in the circumferential direction of the outer cylinder to reduce obstruction of the exhaust gas flow path and minimize the impact on exhaust gas emission. Simultaneously, the heating module operates.

Disclosed is an exhaust device provided with: an exhaust chamber (65) provided so as to overlap an internal combustion engine (3) in plan view; an exhaust pipe (61) that passes below the internal combustion engine from an exhaust port (36) of the internal combustion engine and has an opening (61c) in the exhaust chamber; a catalyst holding pipe (80) which is held in the exhaust pipe, at least a portion of which is provided in the exhaust chamber, and which is filled with a catalyst (8); and an exhaust gas sensor (91) that is provided on a sensor attachment boss part (93) that is provided on the exhaust pipe (61) so as to penetrate through the exhaust chamber (65) and a rear exhaust pipe (61b) that constitutes the exhaust pipe, is housed in the exhaust chamber, and holds the catalyst holding pipe, and thereby, the exhaust gas sensor (91) is attached to the sensor attachment boss part (93), and the exhaust gas sensor (91) is attached to the sensor attachment boss part (93). When exhaust gas sensors are arranged in front of and behind a catalyst in an exhaust pipe for properly diagnosing deterioration of the catalyst for exhaust gas treatment, the length of an exhaust path in the front-back direction can be compactly set, the detection accuracy of the exhaust gas sensors can be improved, emission can be improved, and climate change or influence can be alleviated.

An exhaust system for a vehicle having an internal combustion engine includes an exhaust pipe configured to receive an exhaust gas flow from the engine at a predetermined first velocity, and an exhaust gas sensor assembly coupled to the exhaust pipe and in fluid communication with an interior of the exhaust pipe to sense a predetermined constituent contained within the exhaust gas flow. The exhaust gas sensor assembly includes a sensing element disposed at least partially within a protection tube assembly having a plurality of apertures configured to receive a sensor flow (SF) portion of the exhaust gas flow. The plurality of apertures has a combined total flow area that provides a surface averaged total velocity at the sensing element to be greater than or equal to 70% of the first velocity to thereby increase a dynamic response of the exhaust gas sensor assembly.

The invention relates to a ceramic sensor element (10) for an exhaust gas sensor, wherein the ceramic sensor element (10) is constructed in a layered and elongated manner, wherein the ceramic sensor element (10) has an end region facing the exhaust gas in the longitudinal direction, wherein the ceramic sensor element (10) has a cavity (30) extending in the layer direction in its interior, wherein the ceramic sensor element (10) has an electrochemical pump unit (38) having a first electrode (16) subjected to the exhaust gas (100), a second electrode (18) arranged in the cavity (30), and a solid electrolyte (14) which connects the first electrode (16) to the exhaust gas (100). 16) is connected to the second electrode (18), wherein the ceramic sensor element (10) has a gas inlet hole (64) in the end area facing the exhaust gas, the gas inlet hole extends perpendicularly to the layer direction into the ceramic sensor element (10) and connects the cavity (30) to the exhaust gas (100), wherein the ceramic sensor element (10) has a porous thermal shock protection layer (62) in the end area facing away from the exhaust gas, the thermal shock protection layer covering the gas inlet hole (64), characterized in that the cross-sectional area of ​​the gas inlet hole (64) toward the thermal shock protection layer (62) is larger than the cross-sectional area toward the cavity (30).

The utility model relates to a harmful gas treatment device for producing tris (hydroxymethyl) aminomethane. The harmful gas treatment device comprises a pretreatment box, a neutralization box and a detection box, an air inlet pipe with the other end penetrating through and extending into the pretreatment box is fixedly mounted on the left side of the pretreatment box, a particulate matter filter is slidably mounted in the pretreatment box, a fan is fixedly mounted at the top of the pretreatment box, and the right side of the fan communicates with the interior of the pretreatment box through a pipeline; solid particles and impurities in the harmful gas are removed, subsequent acid-base neutralization is facilitated, after acid-base neutralization is completed, the gas enters the detection box through a pipeline, the concentration of the harmful gas is detected through a waste gas sensor, if the harmful gas meets the emission standard, a valve of an exhaust pipe is opened, the harmful gas can be discharged, otherwise, a valve of a return pipe is opened, and the harmful gas can be discharged. The harmful gas is circularly purified, so that the discharged gas reaches the standard, and the acid-base neutralization reaction efficiency in the neutralization box is higher.

Method for a machine, comprising: Indicating cylinder-to-cylinder imbalance based on each of the exhaust air-fuel ratio (LAMavg) estimated by an exhaust gas sensor (126), the exhaust manifold pressure (Pavg) estimated by a pressure sensor (124), and the individual cylinder torque (TQavg) estimated by a crankshaft torque sensor (200, 210); wherein the indicating based on the exhaust air-fuel ratio (LAMavg) is based on the exhaust air-fuel ratio (LAMavg) weighted with a first confidence factor (c1), the indicating based on the exhaust manifold pressure (Pavg), based on exhaust pressure weighted by a second confidence factor (c2), and specifying based on individual cylinder torque (TQavg) based on the individual cylinder torque (TQavg) weighted by a third confidence factor (c3); further comprising calculating a combined imbalance parameter based on the weighted exhaust air-fuel ratio (LAMavg), the weighted exhaust manifold pressure (Pavg), and the weighted individual cylinder torque (TQavg) for each engine cylinder; and by means of a control device (12) provided with computer-readable instructions stored in a non-volatile memory, Determining a first confidence factor (c1) of the estimated exhaust gas air-fuel ratio (LAMavg) based on fuel type, Determining a second confidence factor (c2) of the estimated exhaust pressure based on valve timing, Determining a third confidence factor (c3) of the estimated individual Cylinder torque (TQavg) based on exhaust temperature, indicating cylinder-to-cylinder imbalance based on two or more of the estimated exhaust air-fuel ratio (LAMavg) weighted by the first confidence factor (c1), the estimated exhaust manifold pressure (Pavg) weighted by the second confidence factor (c2) and the estimated individual cylinder torque (TQavg) weighted by the third confidence factor (c3), and applying an air-fuel ratio correction to one or more cylinders (30) based on the indication.

An engine (40) for a straddle-type vehicle (1). The straddle-type vehicle (1) is to be mounted on a vehicle frame (10) in which a down frame (14) extends downward from a head pipe (11). The engine (40) includes a cylinder head (43) having an exhaust port (47) formed thereon, an exhaust pipe (70), and an exhaust gas sensor (84) attached to the exhaust pipe (70). The exhaust pipe (70) extends downward passing through a first lateral side of the down frame (14), crosses a front side of the down frame (14), and extends upward passing through a second lateral side of the down frame (14). A part of the exhaust pipe (70) that crosses the down frame (14) is a straight portion (73). The exhaust gas sensor (84) is attached to the straight portion (73) and overlaps the down frame (14) from the front side.

Method for operating an internal combustion engine with multiple cylinders, namely a method for determining the component-selective oil consumption of the individual components of the internal combustion engine, in particular individual cylinders and / or turbochargers, wherein each component of the internal combustion engine for which a component-selective oil consumption determination is to be carried out is assigned an individual exhaust gas sensor, wherein each exhaust gas sensor is exposed to a reference gas for a defined period of time during operation of the internal combustion engine and subsequently again to exhaust gas, wherein a component-specific sensor drift is determined for each exhaust gas sensor, and wherein the component or components exhibiting increased oil consumption relative to the other component or components are determined from the component-specific sensor drift of all exhaust gas sensors.

Method for detecting an ammonia slip in an exhaust gas aftertreatment system of an internal combustion engine (1), which has an SCR catalyst (80) and in which, for nitrogen oxide reduction, an ammonia-releasing reducing agent solution is metered into the exhaust gas flow (20) by means of a metering unit (110) in the flow direction of the exhaust gas upstream of the SCR catalyst (80), wherein a cross-sensitivity to nitrogen oxides and ammonia of at least one NO x -Sensor formed exhaust gas sensor (90), which is arranged in the flow direction of the exhaust gas behind the SCR catalyst (80) in the exhaust gas duct (30), is used to detect an ammonia breakthrough, characterized in that to check the plausibility of an ammonia slip, a difference signal is formed by taking from the output signal of the exhaust gas sensor (90) behind the SCR catalyst (80) as a measure for the sum of a nitrogen oxide and an ammonia concentration (204, 205) a value for the NO x-concentration is subtracted before the SCR catalyst (80), and the temporal course of the difference signal or the course of variables derived therefrom is evaluated and compared with applicable limit values.

Gas heat pump system that features: a compressor of an air conditioning module; a gas engine that generates a driving force for the compressor; an exhaust gas turbocharger that feeds at least a proportion of exhaust gas emitted from the gas engine back to the gas engine as recirculated exhaust gas; and an exhaust gas sensor configured to detect the concentration of pollutants contained in the exhaust gas; and a control unit that controls the operation of the exhaust gas turbocharger, the exhaust gas turbocharger features: a turbocharger impeller that exerts pressure on the recirculated exhaust gas and feeds the resulting recirculated exhaust gas to the gas engine; and a turbocharger motor that rotates the turbocharger impeller, and the control system is adjusted to increase the speed of the turbocharger motor, when the measured concentration is equal to or higher than a first reference concentration.

The invention provides a saddle type vehicle. In a saddle-type vehicle, an engine unit including a unit-type swing engine, a catalyst device, and an exhaust gas sensor is made compact. A saddled vehicle is provided with: a unit swing engine (13) that has a crankcase (43) and a cylinder section (44) that extends from the crankcase (43) such that the cylinder axis extends in the front-rear direction of the vehicle, the unit swing engine (13) being swingably supported by a vehicle body frame (12); a radiator (60) disposed on the side of the crankcase (43); an exhaust pipe (77) connected to the cylinder section (44); a catalyst device (121) provided in the exhaust pipe (77); and an exhaust gas sensor (141) provided to the exhaust pipe (77), the catalyst device (121) and the exhaust gas sensor (141) being disposed apart from the radiator in the vehicle front-rear direction in a side view.

A fuel injection control device (40) configured to control a fuel injection system (1), the fuel injection system including an accumulator (32) configured to store a high-pressure fuel, a direct injection fuel injection valve (30) configured to inject a high-pressure fuel in the pressure accumulator directly into a combustion chamber (21) of an internal combustion engine (10), and an exhaust gas sensor (24, 36) configured to detect a component in the exhaust gas from the internal combustion engine, the fuel injection control device comprising: a timing setting unit (43) configured to set a fuel injection timing in a second half of a compression stroke of the internal combustion engine when a component amount of a reduction target component in the exhaust gas detected by the exhaust gas sensor is greater than or equal to a predetermined value, under the condition that the internal combustion engine satisfies a predetermined high temperature condition at a predetermined calculation timing set for each combustion cycle of the internal combustion engine, and an injection control unit (45) configured to calculate an injection period of fuel based on the injection timing set by the timing setting unit, and to control the fuel injection valve based on the injection timing and injection period.

A controller for an internal combustion engine, the internal combustion engine comprising cylinders, a catalyst configured to purify exhaust gas and configured to store oxygen, and an exhaust gas sensor disposed on a downstream side of the catalyst and configured to detect oxygen, the controller comprising: a processing circuit, wherein: the processing circuit is configured to perform a richening process that supplies exhaust gas with a rich air-fuel ratio to the catalyst until the exhaust gas sensor detects that the exhaust gas has a rich air-fuel ratio; the processing circuit is configured such that, after the exhaust gas sensor detects that the exhaust gas has a rich air-fuel ratio in the enrichment process, it executes an air supply process which supplies air to the catalyst until the exhaust gas sensor detects that the exhaust gas has a lean air-fuel ratio; the processing circuit is configured to perform an oxygen storage capacity estimation process which estimates an oxygen storage capacity of the catalyst by accumulating an amount of air supplied to the catalyst until the exhaust gas sensor detects that the exhaust gas has a lean fuel ratio in the air supply process; and the air supply process comprises stopping the fuel supply to one or more of the cylinders and performing combustion at an air-fuel ratio less than or equal to a stoichiometric air-fuel ratio in one or more remaining cylinders, such that the cylinders supply an exhaust gas to the catalyst which is controlled overall to a lean air-fuel ratio.

A method of monitoring an exhaust gas sensor coupled in an engine exhaust in an engine is provided. The method includes entering into a variable displacement engine (VDE) mode wherein intake and exhaust valves of a first subset of cylinders of the engine are activated and intake and exhaust valves of a second subset of cylinders of the engine are deactivated prior to a reduced traction fuel shut-off transition; and executing a six-pattern diagnostic during fuel shut-off to identify exhaust gas sensor degradation.

An exhaust gas sensor assembly for a vehicle includes a sampling tube having a proximal end connectable to a housing and a distal end configured to be suspended with a cavity of the housing. The tube defines a hollow center, an inlet, an outlet, and an exhaust gas flow path extending from the inlet, through the hollow center, and to the outlet. An exhaust gas sensor is disposed in the hollow center at the proximal end and includes a sensing element disposed in the exhaust gas flow path. a flow guide is disposed in the hollow center between the inlet and the sensing element and is configured to redirect the flow path through a passageway defined between the tube and the flow guide.

The invention discloses a motor vehicle exhaust pollution monitoring system and a purification device thereof, and relates to the technical field of automobile accessories, the motor vehicle exhaust pollution monitoring system comprises a monitoring system and a metal shell, the monitoring system comprises an exhaust gas sensor, an engine control unit, an exhaust aftertreatment system, a catalytic converter, a diagnosis and maintenance interface and a remote control platform; the metal shell comprises a first metal shell, a second metal shell, a first mounting flange, a second mounting flange, a third mounting flange and a fourth mounting flange, the first mounting flange is fixedly mounted at the left end of the first metal shell, and the second mounting flange is fixedly mounted at the right end of the second metal shell; the metal shell is arranged to be in a split type, rapid disassembly and assembly of a catalyst ceramic carrier in the catalytic converter are achieved, tools do not need to be used for assistance, limitation is small, operation is convenient and rapid, time and labor are saved, and practicability is high.

An engine for a straddle-type vehicle. The straddle-type vehicle is to be mounted on a vehicle frame in which a down frame extends downward from a head pipe. The engine includes a cylinder head having an exhaust port formed thereon, an exhaust pipe connected to the exhaust port of the cylinder head, and an exhaust gas sensor attached to the exhaust pipe. The exhaust pipe extends downward passing through a first lateral side of the down frame, crosses a front side of the down frame, and extends upward passing through a second lateral side of the down frame. A part of the exhaust pipe that crosses the down frame is a straight portion. The exhaust gas sensor is attached to the straight portion and overlaps the down frame from the front side.

The invention relates to a method for monitoring a secondary air supply in an internal combustion engine, the internal combustion engine having a secondary air supply, a device for determining a pressure pS in the secondary air supply, and an exhaust gas lambda sensor for determining a current exhaust gas lambda value lambda sens, the method comprises the following steps: a) determining a first secondary air mass flow # imgabs0 # b) dependent on an effective throttling surface Aeff by means of a throttling equation and depending on a pressure pS in the secondary air supply device a second secondary air mass flow # imgabs3 # is determined starting from the measured exhaust gas lambda value [lambda] sens and taking into account the primary air mass flow # imgabs1 # and the supplied fuel mass flow # imgabs2 # of the internal combustion engine; c) an effective throttle surface Aeff is derived from the first secondary air mass flow # imgabs4 # determined in step a) and the second secondary air mass flow # imgabs5 # determined in step b); and d) monitoring the effective throttle surface Aeff thus obtained using at least one predefined threshold value.