476 results about "Lean combustion" patented technology

The present invention provides a plasma arc torch that can be used for lean combustion. The plasma arc torch includes a cylindrical vessel, an electrode housing connected to the first end of the cylindrical vessel such that a first electrode is (a) aligned with a longitudinal axis of the cylindrical vessel, (b) extends into the cylindrical vessel, and (c) can be moved along the longitudinal axis, a linear actuator connected to the first electrode to adjust a position of the first electrode, a hollow electrode nozzle connected to the second end of the cylindrical vessel such that the center line of the hollow electrode nozzle is aligned with the longitudinal axis of the cylindrical vessel, and wherein the tangential inlet and the tangential outlet create a vortex within the cylindrical vessel, and the first electrode and the hollow electrode nozzle creates a plasma that discharges through the hollow electrode nozzle.

A method is provided for control of a direct-injection engine operated with controlled auto-ignition (HCCI) during load transient operations between modes of lean combustion low load (HCCI / Lean) and stiochiometric combustion medium load (HCCI / Stoich.). The method includes 1) operating the engine at steady state, within a homogeneous charge compression-ignition (HCCI) load range, with fuel-air-exhaust gas mixtures at predetermined conditions, for each speed and load, and controlling the engine during changes of operating mode between one to another of the HCCI / Stoich. medium load mode and the HCCI / Lean lower load mode by synchronizing change rates of predetermined controlled inputs to the current engine fueling change rate.

A main air compressor delivers a compressed ambient gas flow with a compressed ambient gas flow rate to a turbine combustor. A fuel stream with a flow rate is delivered to the turbine combustor and mixed with the compressed ambient gas flow and an exhaust gas flow and burned with substantially stoichiometric combustion to form the exhaust gas flow and drive a turbine, thus operating the power plant at a first load. A portion of the exhaust gas flow is recirculated from the turbine to the turbine compressor and a portion is delivered to an exhaust path. The fuel stream flow rate and the compressed ambient gas flow rate are reduced, and substantially stoichiometric combustion is maintained and the power plant is operated at a second load. The fuel stream flow rate is further reduced and lean combustion is achieved and the power plant is operated at a third load.

A gaseous-fueled reciprocating internal combustion engine includes a carburetor having a throttle valve that is controlled by a speed governor. A proportional fuel control valve is disposed intermediate a fuel supply and the carburetor, and is controlled by an air fuel computing device. The computing device generates a control signal to adjust the fuel control valve based on a governor sensed variable indicative of engine speed, sensed engine torque, a governor output signal from the governor indicative of an opening position of the throttle valve wherein 100% corresponds to a wide open throttle position, and 0% corresponds to a closed position, and a lean combustion control map containing predetermined set point values stored in memory. During operation, the control valve is responsive to the control signal generated by the computing device for adjustment of a fuel flow therethrough so as to obtain a ratio of air to fuel provided to the engine that is substantially at a lean misfire limit of the engine, thereby reducing fuel consumption, NOx emissions, and reducing exhaust gas temperatures. Alternatively, the control signal is generated using engine speed alone.

The present invention is an exhaust gas purification catalyst equipment, and a method of use thereof, formed by arranging a selective catalytic reduction type catalyst for purifying nitrogen oxides in exhaust gas exhausted from lean combustion engines using ammonia or urea as a reducing agent, it is provided with a selective catalytic reduction type catalyst, characterized in that said catalyst comprises a lower-layer catalyst layer (A) having an oxidative function for nitrogen monoxide (NO) in exhaust gas and an upper-layer catalyst layer (B) having an adsorbing function for ammonia on the surface of a monolithic structure type carrier (C), and that the lower-layer catalyst layer (A) comprises a noble metal component (i), an inorganic base material constituent (ii) and zeolite (iii), and the upper-layer catalyst layer (B) comprises substantially none of component (i) but the component (iii), in a flow path of exhaust gas, characterized in that a spraying means to supply an urea aqueous solution or an aqueous ammonia solution is arranged in the downstream of the aforementioned oxidation catalyst and in the upstream of aforementioned selective catalytic reduction type catalyst.

This invention provides a method of reducing nitrogen oxides in an oxygen containing exhaust stream using ethanol as a reductant for plasma-assisted selective catalytic reduction. The exhaust gas, generated from a diesel engine or other lean-burn power source, comprises nitrogen oxides, especially NO. Ozone generated from a plasma reactor is injected into the exhaust stream to convert NO to NO2 and the plasma injection is followed by the addition of ethanol. The NO2 is then reduced by contacting the exhaust stream with a dual-bed catalytic reactor comprising BaY (or NaY) and CuY zeolite catalysts in the presence of ethanol as the reductant. The plasma power density and the molar ratio of ethanol to NOx fed to the catalytic reactor are controlled as a function of the catalyst temperature for the best performance of the plasma-catalyst system. An average conversion of NOx to N2 of at least 90% is achieved over the temperature range of 200–400° C.

An exhaust emission control system for an internal combustion engine is provided which includes a NOx storage / reduction catalyst disposed in an exhaust passage of the engine, and a NOx sensor positioned in the exhaust passage downstream of the catalyst. A controller of the system performs a rich-spike operation to temporarily operate the engine at a rich air / fuel ratio each time a NOx storage state of the catalyst satisfies a predetermined rich-spike condition during a lean-burn operation. When the degree of degradation of the catalyst is determined by comparing the output of the NOx sensor with a predetermined evaluation value, the rich-spike condition is changed so that the amount of NOx stored in the catalyst at the time of a start of the rich-spike operation during a degradation determination period is made larger than that reached during a period other than the determination period.

For the purpose of improving the fuel efficiency by lean combustion and enhancing the fuel efficiency improvement effects by performing compression ignition efficiently in some cylinders, a multi-cylinder spark ignition engine is constructed such that exhaust gas, that is exhausted from preceding cylinders 2A, 2D on the exhaust stroke side among pairs of cylinders whose exhaust stroke and intake stroke overlap in a low load, low rotational speed region, is directly introduced through an inter-cylinder gas passage 22 into following cylinders 2B, 2C on the intake stroke side and only gas exhausted from the following cylinders 2B, 2C is fed to an exhaust passage 20, which is provided with a three-way catalyst 24. Combustion controller is provided that controls the combustion of each of the cylinders such that combustion is conducted by forced ignition in a condition in which the air / fuel ratio is a lean air / fuel ratio which is larger by a prescribed amount than the stoichiometric air / fuel ratio in the preceding cylinders 2A, 2D and, in the following cylinders 2B, 2C, fuel is supplied to burnt gas of lean air / fuel ratio introduced from the preceding cylinders 2A, 2D and combustion is conducted by compression ignition.

The present invention relates to a catalyst composition comprising a carrier substrate, a layer (i) coated on said carrier substrate comprising at least one precious group metal, a layer (ii) comprising Rh, and a layer (iii) comprising Pd and / or Pt and being substantially free of Ce, Ba and Rh, wherein the layer (iii) has a lower weight than the layer (i) or the layer (ii). Furthermore, the present invention relates to a method for treating an exhaust gas stream using said catalyst composition.

In an exhaust gas control device-equipped internal combustion engine, particulate matter produced in conjunction with combustion of gasoline in a combustion chamber is oxidized by an exhaust gas control device provided in an exhaust passage. The engine includes air-fuel ratio control changer that changes between a feedback control toward a stoichiometric air-fuel ratio whereby an amount of oxygen in exhaust gas is reduced and a feedback control toward a lean-burn combustion side whereby the amount of oxygen in exhaust gas is increased, if the oxidation speed of particulate matter in the exhaust gas control device provided in the exhaust passage is slow, or if the amount of deposit of particulate matter is great.

A gaseous-fueled reciprocating internal combustion engine includes a carburetor having a throttle valve that is controlled by a speed governor. A proportional fuel control valve is disposed intermediate a fuel supply and the carburetor, and is controlled by an air fuel computing device. The computing device generates a control signal to adjust the fuel control valve based on a governor sensed variable indicative of engine speed, sensed engine torque, a governor output signal from the governor indicative of an opening position of the throttle valve wherein 100% corresponds to a wide open throttle position, and 0% corresponds to a closed position, and a lean combustion control map containing predetermined set point values stored in memory. During operation, the control valve is responsive to the control signal generated by the computing device for adjustment of a fuel flow therethrough so as to obtain a ratio of air to fuel provided to the engine that is substantially at a lean misfire limit of the engine, thereby reducing fuel consumption, NOx emissions, and reducing exhaust gas temperatures. Alternatively, the control signal is generated using engine speed alone.

A variety of methods and arrangements for controlling the exhaust gas temperature of a lean burn, skip fire controlled internal combustion engine are described. In one aspect, an engine controller includes an aftertreatment system monitor and a firing timing determination unit. The aftertreatment monitor obtains data relating to a temperature of one or more aftertreatment elements, such as a catalytic converter. Based at least partly on this data, the firing timing determination unit generates a firing sequence for operating the engine in a skip fire manner such that the temperature of the aftertreatment element is controlled within its effective operating range.

In domestic installations of any type of furnace or equivalent, proof of lean combustion is necessary to satisfy requirements of certification agencies. Exhibiting proof of lean combustion during the operation of an integrated fuel reformer and fuel cell system can be problematic because the point of combustion and its nature may shift during operation. In addition, the preferred ratio of fuel to air in these fuel-reforming systems is often near a stoichiometry of one. In the present invention, the combination of a flame-detecting device, a temperature sensing device and an oxygen or hydrocarbon sensor is used to verify the occurrence of combustion, and show proof of lean combustion.

An internal combustion engine includes an in-cylinder injection valve and an intake port injection valve. The engine is operated in a combustion mode that is selected from at least stratified lean combustion and homogeneous combustion. An ECU selects the combustion mode according to the operational state of the engine, and controls the fuel injection valves in a fuel injection mode that corresponds to the selected combustion mode. When a misfire is detected while the engine is operated in the stratified lean combustion or the homogeneous combustion, the ECU switches the fuel injection mode such that the ratio of the amount of fuel injected from the intake port injection valve to the entire amount of fuel supplied into the cylinder is increased. As a result, misfires are suppressed while preventing the fuel economy from deteriorating.

A flex fuel internal combustion engine system includes means for sensing ethanol concentration of the fuel. If the ethanol concentration is determined to be above a given threshold, engine operation is adjusted for lean combustion of the fuel. An aftertreatment system is provided to remove harmful emissions from the exhaust.