Abstract: An exhaust temperature control system for a displacement on demand (DOD) diesel engine includes a first and a second cylinder and an air intake that selectively enables air flow into the first cylinder. A fuel injector selectively enables fuel flow into the first cylinder. A controller increases an exhaust temperature of the diesel engine by closing the air intake and disabling fuel flow through the fuel injector to deactivate the first cylinder.

Abstract: An in-cylinder ion sensor provides a signal representative of the air/fuel ratio of the charge mixture as an engine starts. The signal representative of the air/fuel ratio is used as a feedback signal for an electronic control unit to perform cold-start closed-loop control during an initial operating period from a cold-start before an on-board oxygen sensor is able to warm up. After reaching a functional operating temperature, the oxygen sensor provides a signal that is used as an adaptive calibration tool which allows the electronic control unit to calibrate the ion sensor signal and use that signal for controlling the air/fuel ratio during cold start operation.

Abstract: Injection of secondary air (AI) into an exhaust gas pipe upstream of an exhaust gas purification catalyst is performed after a startup of an engine, in order to accelerate the warm-up of the catalyst. If the degree of catalyst warm-up during the AI is greater than or equal to a predetermined criterion degree of the warm-up and the engine output is greater than or equal to a criterion output, the injection of secondary air is stopped and exhaust gas purification on the catalyst is conducted so as to curb degradation of emissions.

Abstract: A rapid catalyst warm-up control device for an internal combustion engine performs irregular injection dither control during the rapid catalyst warm-up control after starting the engine. In the irregular injection dither control, injection modes are switched after every fuel injection to the cylinders (every 180° CA for a 4-cylinder engine) between a lean injection mode and a rich injection mode in such a pattern that rich injections will not occur consecutively for the same cylinder (dither cycle=540° CA, 900° CA, 1080° CA, or the like). In the lean injection mode, fuel is injected such that the air-fuel ratio is leaner than the stoichiometric ratio, and in the rich injection mode, air-fuel ratio is richer than the stoichiometric ratio. The rich gas emitted from the cylinders where the rich injection has been performed is thus allowed to flow through a different catalyst region every time instead of flowing only through the same region.

Abstract: An exhaust gas purifying system for an engine, including a HC trap catalyst disposed in an exhaust passage and operative to trap HC contained in the exhaust gas, and a control unit being programmed to: upon activating the HC trap catalyst after the engine is started, control a target excess air ratio to a preset value smaller than a normal value to which the target excess air ratio is controlled when the HC trap catalyst is activated, to thereby rise an exhaust gas temperature; and increase the target excess air ratio as the temperature of the HC trap catalyst rises, to thereby increase a heat quantity generated upon oxidation of the HC trapped by the HC trap catalyst.

Abstract: The invention relates to the starting of an internal combustion engine. The engine is coupled to an exhaust aftertreatment device that has a minimal threshold temperature for proper operation. Within a certain period of time after engine start, the load on an electrical generator driven by the engine is increased. Also, the air intake is throttled to reduce the intake manifold pressure to a target pressure. Both measures provide faster engine and catalyst warm-up and, thus, reduced emissions, particularly for a diesel engine in connection with an oxidation catalyst.

Abstract: The recycling timing schedule for a diesel particulate filter (DPF) can be easily and accurately determined. There is a differential pressure sensor that detects differential pressure &Dgr;P in the DPF, and an airflow meter that detects the flow velocity v in an exhaust path. An ECU calculates the quantity of deposited fine exhaust particles ML according to: ML=[&Dgr;P−(A&mgr;v+C&rgr;v2)]/(B&mgr;v+D&rgr;v2) Recycling of the filter is determined according to a determination formula used to compare the calculated deposited quantity ML to a reference quantity. In this way, the deposited quantity can be accurately obtained without using a map.

Abstract: Method and apparatus for controlling a vehicle so as to purify an exhaust emission from an internal combustion engine with an exhaust-emission purifying catalyst disposed in an exhaust system of the engine, and such that the engine is brought into a temporary engine-stop state while a predetermined vehicle condition is satisfied, wherein the engine is operated for heating the catalyst, when a temperature of the catalyst has been lowered below a predetermined lower limit threshold, even while the predetermined vehicle condition is still satisfied. The catalyst maintains an exhaust-emission purifying ability at a temperature above the lower limit threshold. When the catalyst temperature has been raised to a predetermined upper limit threshold, as a result of the engine operation, the engine is restored to the temporary engine-stop state if the predetermined condition is still satisfied.

Abstract: In a cold condition before a warming-up completion in a diesel engine, when an engine power is less than a predetermined value, an air excess rate is controlled to a second air excess rate being smaller than a target air excess rate set after the warming-up completion, thereby promoting a warming-up of an exhaust gas purification catalyst due to rise of an exhaust gas temperature, and when the engine power is more than the predetermined value, the air excess rate is controlled to a first air excess rate being larger than the target air excess rate, thereby decreasing HC emission quantity from a combustion chamber. Accordingly, a total emission quantity of HC at the clod condition is decreased.

Abstract: A device for purifying exhaust gas of a diesel engine equipped with a continuous regeneration type diesel particulate filter arranged in the exhaust gas passage of the engine. The device includes an intake air shutter arranged in the intake air passage of the engine, an exhaust gas temperature region detector for detecting an exhaust gas temperature region of the engine, a controller for controlling the opening degree of the intake air shutter when the exhaust gas temperature region of the engine, detected by the exhaust gas temperature region detector, is lower than a predetermined temperature region, and an exhaust valve-operating mechanism equipped with an exhaust gas introduction mechanism for opening the exhaust valve of the engine for a short period of time during the intake stroke of a cylinder of the diesel engine, to introduce exhaust gas into the cylinder.

Abstract: A process for operating an exhaust gas system comprises: producing an exhaust gas flow, introducing the exhaust gas flow to a system comprising a restricting device in fluid communication with an exhaust emission control device, and an exhaust conduit comprising an exhaust throttle device, restricting the flow of the exhaust gas stream to the restricting device, and discharging the exhaust gas stream from the restricting device into the exhaust emission control device. The flow is sufficiently restricted such that the exhaust gas stream discharged into the exhaust emission control device has a temperature perform a desired function selected from the group consisting of regeneration and light-off.

Abstract: A state determining apparatus for an exhaust gas purifier is provided for accurately determining the state of the exhaust gas purifier including an adsorbent for adsorbing hydrocarbons, including a deterioration of the adsorbent, in accordance with an ignition time of an internal combustion engine. The state determining apparatus for an exhaust gas purifier is arranged in an exhaust system of the internal combustion engine for determining the state of the exhaust gas purifier including the adsorbent capable of adsorbing hydrocarbons and moisture in exhaust gas. The state determining apparatus has a humidity sensor arranged at a location downstream of the adsorbent in the exhaust system for detecting the humidity of exhaust gases, and an ECU for determining the state of the adsorbent in accordance with the humidity of exhaust gases detected by the humidity sensor, and the ignition time of the internal combustion engine.

Abstract: A diesel engine (10) having a selective catalytic reduction system with a urea tank (12). A heater element (26) is mounted in the urea tank and another heating element (34) is mounted in the engine (10) for cold weather starts. Both heating elements (24) and (26) are connected to a common cord (18) which has at its distal end a common electrical plug (16) for plugging into an electrical receptacle.

Abstract: An internal combustion engine, in particular for a motor vehicle, in which fuel may be injected into a combustion chamber during an intake phase in a first mode of operation or during a compression phase in a second mode of operation, and in which exhaust gases may be sent to a catalytic converter. A control unit determines a temperature difference between an actual exhaust gas temperature and a setpoint exhaust gas temperature at an operating point having a low exhaust gas temperature. In addition, at least one additional injection after combustion is implemented by the control unit as a function of the temperature difference.

Abstract: A heating of a catalytic converter in the exhaust gas of an internal combustion engine is presented which can be operated in different operating modes and wherein at least one of several heating measures can be selected so that, at first, an estimate can be made for several heating measures as to whether an individual heating measure can make the desired heating effect available and that it is further estimated whether an individual heating method can be carried out in the instantaneous operating state with a view to the exhaust-gas values and the operating mode of the internal combustion engine, which is necessary for carrying out the heating measure; and that that operating mode is requested wherein the requests can best be satisfied and that at least one possible heating measure is activated in dependence upon the instantaneous mode of operation. The invention further is directed to an electronic control unit for carrying out the method.

Abstract: Exhaust gas temperature is increased to improve the effectiveness of an after-treatment system having an activation temperature by deactivating one or more engine cylinders to increase the exhaust gas temperature from the remaining cylinders (during acceleration) or to decreasing exhaust gas flow rate (during deceleration or idling). In the system of the invention, a controller effects the deactivation and reactivation of cylinders and/or decrease and increase of exhaust gas flow in response to one or more sensors providing input of exhaust gas temperature or information from which exhaust gas temperature can be approximated. By achieving and maintaining the activation temperature, the present invention improves the effectiveness of after-treatment devices thereby lowering regulated emissions to desired levels.

Abstract: A controlled exhaust brake for an engine comprises an exhaust restrictor located in an exhaust system downstream of an exhaust manifold of an engine. An actuator operably associated with the restrictor adjusts the restrictor. A pressure sensor operably associated with the exhaust manifold senses pressure in the exhaust manifold. A controller determines a set pressure in the exhaust manifold correlated with speed of the engine. The controller is in communication with the pressure sensor and the actuator, and causes adjustment of the restrictor in order to achieve and maintain the set pressure in the exhaust manifold.

Abstract: A method to regulate catalyst temperature by adjusting engine air and fuel amounts. The method provides catalyst temperature regulation while reducing fuel consumption.

Abstract: The present invention involves thermal management of an integrated emission reduction system for the removal of particulate matter (PM) and nitrogen oxides (NOx) from diesel engine exhaust streams. The inventive integrated emission reduction system may include a diesel particulate filter (DPF), a heat source for adjusting the temperature of the exhaust stream entering the DPF, at least one selective catalytic reducer of NOx, a heat exchanger for adjusting the temperature of the exhaust stream entering the NOx reducer, and a computing device for monitoring the temperature and/or pressure of the exhaust stream entering the DPF and the NOx reducer, and for controlling the operation of the heat exchanger and heat source, thereby improving the efficiency of the DPF and the NOx reducer.

Abstract: Diesel engine is operated in a first warm-up mode in an early warm-up period after startup so as to accelerate activation of the catalyst, and then in a second warm-up mode in a late warm-up period after the early warm-up period so as to maintain activity of the catalyst. The first warm-up mode provides more energy to the catalyst with exhaust gases than the normal operation mode of the diesel engine. The second warm-up mode provides exhaust gases of higher temperature to the catalyst than the normal operation mode.

Abstract: A reformate/buffer system and method for operating an exhaust emissions control device are disclosed herein. In one embodiment, the reformate/buffer system comprises: a hydride storage bed, a hydride cycling bed disposed in fluid communication with the hydride storage bed, a hydrogen separation device, a reformate flow path, coolant flow passages in thermal communication with the hydride cycling bed, and reformer flow passages in thermal communication with the hydride cycling bed. The reformate flow path is formed by the hydride storage bed, the hydride cycling bed, and the hydrogen separation device and is disposed in fluid communication with the hydride storage bed and hydride cycling bed.

Abstract: A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

Abstract: There is provided an exhaust emission control apparatus for an internal combustion engine which can reduce the emission of toxic substances and quickly activate a catalyst. An exhaust flow control means suppresses the flow of exhaust in an exhaust system when the engine is started. An operative state detecting means detects whether or not the period of time elapsed after a vehicle starts accelerating from standstill is equal to or shorter than a predetermined period of time. While the operative state detecting means detects that the period of time elapsed after the vehicle starts accelerating from standstill is equal to or shorter than the predetermined period of time, an exhaust flow control limiting means stops or reduces the suppression of exhaust flow by the exhaust flow control device.

Abstract: A system for an engine has an upstream emission control device with a washcoat having a predetermined amount of precious metal disassociated with NOx storage material, where the upstream emission control device in a close coupled location to an exhaust manifold of the engine. The system also includes a downstream emission control device coupled to the upstream emission control device. Further, a controller is used for operating the engine lean with retarded ignition timing to generate heat and raise temperatures of said upstream and downstream emission control devices. The controller also determines whether temperature of said upstream device has reached a predetermined value, and in response to said determination, operates the engine rich at least to reduce NOx stored in said upstream emission control device during said lean operation.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided for switching a switching valve at an optimal timing in accordance with an actual activated state of a catalyzer to achieve an optimal exhaust gas characteristic.

Abstract: Diesel engine is operated in a first warm-up mode in an early warm-up period after startup so as to accelerate activation of the catalyst, and then in a second warm-up mode in a late warm-up period after the early warm-up period so as to maintain activity of the catalyst. The first warm-up mode provides more energy to the catalyst with exhaust gases than the normal operation mode of the diesel engine. The second warm-up mode provides exhaust gases of higher temperature to the catalyst than the normal operation mode.

Abstract: The invention relates to a method for warming up at least one catalytic converter that is arranged downstream from a spark-ignition, direct injection internal combustion engine. To this end, an exhaust gas temperature is at least temporarily increased by at least one measure, which is executed by the engine, after the conclusion (t1) of the engine start of the internal combustion engine. The measures, which are executed by the engine, consist of a multiple injection during which at least two fuel injections into the cylinder are carried out within an induction cycle and compression cycle of a cylinder of the internal combustion engine, and/or said measures consist of a spark retarding. The invention provides that the measure executed by the engine or a combination of measures having the strongest heating action is available, at the earliest, after a retardation of at least two working cycles of the internal combustion engine after the conclusion (t1) of the engine start.

Abstract: A method to deliver spark during a start for an internal combustion engine is described. The method provides individual cylinder spark angle control based on the number of cylinders after synchronization between engine timing and an engine controller are achieved. The method offers improved engine emissions while maintaining engine speed run-up performance.

Abstract: The invention relates to a method for at least temporarily increasing an exhaust gas temperature of a spark-ignition, direction injection internal combustion engine (10) involving at least one measure, which is executed by the engine, whereby this at least one measure consists of a spark retarding and of a multiple injection (ME). During the multiple injection (ME), at least two fuel injections into the cylinder (12) are carried out within an induction cycle and compression cycle of a cylinder (12) of the internal combustion engine (10), and the latest of these injections ensues during a compression cycle of the cylinder (12). The invention also relates to the utilization of the method.

Abstract: The invention relates to a method and system for controlling an internal combustion engine (9) in a motor vehicle having a brake booster (1), a low pressure chamber (2) of the brake booster being connected to the intake manifold (8) of the internal combustion engine (9). To ensure that the brake booster (1) functions during a forced warm up of a catalytic converter, the pressure in the brake booster (1) is monitored by pressure sensors (7a, 7b). If too high a pressure is detected, the internal combustion engine (9) is actuated by an engine control system (10) to decrease intake manifold (8) pressure, for example, by increasing the engine speed after startup. Spark retard, a measure for warming up a catalytic converter, is temporarily reduced or eliminated, if increasing engine speed is insufficient to reduce pressure.

Abstract: The invention relates to a method for reducing the exhaust emissions during the cold start of an internal combustion engine (3). According to the method, a starter motor (4) is operated in parallel with the internal combustion engine (3) until the operating temperature of an exhaust gas catalytic converter (1) is reached, to thereby relieve the power demand on the internal combustion engine and thereby to minimize the production of pollutants. The heating of catalytic converter (1) can preferably be accelerated by retarded spark timing, by a delayed shift in automatic transmission (6) and/or by an electrical heater coupled to catalytic converter (1).

Abstract: A temperature estimating apparatus for an internal combustion engine is provided for correctly calculating the temperature of an exhaust device even when the internal combustion engine is started under low temperature conditions. The temperature estimating apparatus comprises an ECU for estimating the temperature of a hydrocarbon adsorbent in an exhaust system of the internal combustion engine through calculations. The ECU calculates an estimated adsorbent temperature of the adsorbent in accordance with an engine rotational speed, an absolute intake pipe inner pressure, an engine water temperature, an intake temperature, and a detected humidity of exhaust gases. This calculation is started when condensation, which has occurred within an intake pipe, is eliminated.

Abstract: An exhaust emission control device comprises an oxidizing catalyst, a particulate filter on which soot is deposited, and a temperature sensor for detecting the temperature of exhaust gas on the upper-stream side of the filter. An intake system of an engine is provided with an EGR valve for returning the exhaust gas to the intake system. If the temperature of the oxidizing catalyst is found to be lower than its active temperature as the particulate filter is regenerated, the catalyst is heated by delaying the injection timing for the main fuel injection of the engine and increasing the EGR gas reflux quantity. Thus, the oxidizing catalyst can be heated up without lowering the fuel-efficiency, and soot on the particulate filter can be efficiently subjected to re-combustion.

Abstract: When starting an engine, it is judged whether a catalyst is in an inactive condition or not and, if it is judged that the catalyst is in an inactive condition, the motor field current is reduced to control the output characteristic of the starter to a high-speed type, thus enabling the engine to be driven at high speed. As the engine rpm during driving rises compared with the normal case (the case where the catalyst is in an active condition), the amount of fuel remaining in the intake port and the cylinder decreases, and the injected fuel properly contributes to combustion. Accordingly, even when the catalyst is in an inactive condition, emissions (of HC) emitted into the atmosphere can be reduced.

Abstract: An engine control system in a vehicle including a variable displacement internal combustion engine, a controller for controlling the displacement of the variable displacement internal combustion engine, and where the controller operates the variable displacement internal combustion engine in a partially displaced operating mode upon startup to increase exhaust gas temperature.

Abstract: At the start of operation of an internal-combustion engine (S10,S12,S14), an exhaust flow is restrained (to raise the exhaust pressure) (S18), secondary air is supplied (S20), and the combustion air-fuel ratio (A/F) is set within the range of rich air-fuel ratios (S16, S22).

Abstract: A direct injection internal combustion engine includes catalysts for purifying exhaust gases, the catalysts being disposed in an exhaust passage of the engine. A control device controls the engine so as to warm up or activate the catalysts. The control device includes a first control part for controlling the engine with an air-fuel ratio of the engine being set at a value in proximity to a stoichiometric air-fuel ratio, an ignition timing being set at a point after a top dead center and a fuel injection timing being set within a compression stroke, and a second control part for controlling the engine with an air-fuel ratio of the engine being set at a value in proximity to a stoichiometric air-fuel ratio, with an ignition timing being set before a top dead center and a fuel injection timing being set within a compression stroke after the first control part controls the engine. The controlling operation performed by the first control part enables stable after-burning and raises the exhaust temperature.

Abstract: A fuel injection control device includes an exhaust purification device for purifying an exhaust gas by catalytic action, an exhaust gas-temperature detection unit for detecting exhaust gas temperature, and a determination unit for determining the amount of the basic fuel injection and basic fuel injection timing from the operational status of a combustion engine, and a control unit for controlling the amount of the fuel injection and fuel injection timing. The control unit retards the fuel injection timing from the basic fuel injection timing when the exhaust gas temperature is lower than the temperature required for the catalytic activation of the exhaust purification device. The control unit also increases the amount of the fuel injection compared to the amount of the basic fuel injection to compensate for the loss of the torque output caused by the retarded fuel injection timing.

Abstract: A method and apparatus controls an internal combustion engine of a vehicle in which an exhaust purifying catalyst capable of storing oxygen is provided in an exhaust system of the engine. The internal combustion engine is adapted to be temporarily stopped when a predetermined condition for stopping the engine is satisfied, and resumes its operation when the predetermined condition is eliminated. The internal combustion engine is operated so as to reduce an amount of oxygen stored in the exhaust purifying catalyst during a temporary stoppage of the engine, before fuel starts being burned for resuming the operation of the engine.

Abstract: A HC adsorption type three-way catalytic converter is arranged in an exhaust gas passage of a diesel engine at a position upstream of a diesel particulate filter or a NOx trapping catalytic converter. Upon need of reactivation of the diesel particulate filter or NOx trapping catalytic converter under cold operation of the engine, a control unit carries out lowering an excess air ratio of the exhaust gas of the engine when the temperature of the catalyst bed of the three-way catalytic converter is lower than or equal to a first predetermined temperature (viz., oxidization activation temperature); raising the excess air ratio of the exhaust gas when the temperature of the catalyst bed of the three-way catalytic converter is higher than the first predetermined temperature but lower than or equal to a second predetermined temperature (viz.

Abstract: A system and method for providing operating conditions that provide higher efficiency NOx reduction in a lean NOx catalyst coupled to a lean-burning internal combustion engine. A catalyst containing reductant is caused to attain a temperature greater than 300° C. After a duration of about 10 seconds at the elevated temperature, the NOx conversion efficiency of the catalyst is increased in the 140-250° C. temperature range.

Abstract: An exhaust system for an internal combustion engine having a plurality of cylinders, comprising: a exhaust manifold for providing fluid communication of exhaust of the plurality of cylinders to a catalytic converter, the exhaust manifold comprising a first exhaust pipe and a second exhaust pipe, the first exhaust pipe being in fluid communication with the second exhaust pipe and the second exhaust pipe being in fluid communication with the catalytic converter, the first exhaust pipe providing a first fluid path for exhaust of a first plurality of cylinders of the engine and the second exhaust pipe providing a second fluid path for exhaust of a second plurality of cylinders of the engine, the second fluid path being shorter than the first fluid path; a controller for determining whether to deactivate the first plurality of cylinders in accordance with a predetermined engine starting condition, wherein deactivation of the first plurality of cylinders causes the second plurality of cylinders to operate at a cond

Abstract: A method to reduce the lightoff temperature of a catalyst. In the method, the working fluid (the fuel and oxidant to be reacted in the presence of the catalyst) is supplemented with a starter fluid at least until the lightoff temperature of the catalyst is reached. Preferably, the amount of starter fuel added is sufficiently small such that a reaction of the starter fuel and oxidant in the presence of the catalyst does not have a sufficient heat release to raise the temperature of the catalyst to the lightoff temperature.

Abstract: A system and method for controlling an internal combustion engine having a plurality of cylinders, at least some of which may be selectively deactivated to provide variable displacement operation, include managing temperature of at least one engine/vehicle component by monitoring the temperature of the component and controlling activation of at least one cylinder to control the temperature of the component. In one embodiment, the engine/vehicle component is an emission control device, such as a catalytic converter.

Abstract: A method for rapidly heating an emission control device in an engine exhaust uses excess air added to the exhaust via an air introduction device. After an engine cold start, the engine is operated to raise exhaust manifold temperature to a first predetermined value by operating the engine with a lean air-fuel ratio and retarded ignition timing. Once the exhaust manifold reaches the predetermined temperature value, the engine is switched to operate rich and air is added via the air introduction device. The added air and rich exhaust gas burn in the exhaust, thereby generating heat and raising catalyst temperature even more rapidly. The rich operation and excess air are continued until either engine airflow increases beyond a pre-selected value, or the emission control device reaches a desired temperature value. After the emission control device reaches the desired temperature, the engine is operated substantially around stoichiometry.

Abstract: In an in-cylinder injection spark-ignition internal combustion engine including a plurality of cylinders and a catalyst device disposed in an exhaust system of the engine, a fuel is injected to at least one selected cylinder selected from the plurality of cylinders to be operated, and subsequently the fuel is injected to all cylinders to be operated. At this time, a warm-up controlled variable for the at least one selected cylinder is smaller than the warm-up controlled variable used when all cylinders are operated. In the in-cylinder injection spark-ignition internal combustion engine, the all cylinder operation is started and the warm-up control is started for all cylinders to warm up the catalyst device disposed in the exhaust system of the engine preferably when a fuel injection pressure exceeds a target value.

Abstract: The ignition timing is sustained at an initial value during a predetermined time beginning at a start of an engine, and is retarded after the predetermined time is elapsed to heat a catalyst at an early time. The predetermined time ends when the negative pressure of an intake pipe or the negative pressure of a brake booster reaches to a predetermined value. That is, the predetermined time is a period, which begins at a start of the engine and ends when a proper negative pressure can be sustained in the brake booster. As a result, it is possible to assure a negative pressure in the brake booster at an early time and to reduce exhaust emission at a start of the engine simultaneously.

Abstract: A method for rapidly heating an emission control device in an engine exhaust uses excess air added to the exhaust via an air introduction device. After an engine cold start, the engine is operated to raise exhaust manifold temperature to a first predetermined value by operating the engine with a lean air-fuel ratio and retarded ignition timing. Once the exhaust manifold reaches the predetermined temperature value, the engine is switched to operate rich and air is added via the air introduction device. The added air and rich exhaust gas burn in the exhaust, thereby generating heat and raising catalyst temperature even more rapidly. The rich operation and excess air are continued until either engine airflow increases beyond a pre-selected value, or the emission control device reaches a desired temperature value. After the emission control device reaches the desired temperature, the engine is operated substantially around stoichiometry.

Abstract: This feature of the present invention comprises a method and apparatus to retard the spark time. As a result, the catalyst heats up quickly during the cold start. The retard spark control method of the present invention uses a closed loop to adjust the engine retard limit during an engine cold start to retard the engine spark as much as possible without engine misfire and with minimum partial burn. The increased exhaust temperature heats up the catalyst more quickly than conventional open loop approaches, which as a result, reduces hydrocarbon emissions. The closed loop retard spark control using ionization current feedback consists of four major components or functions, an error and gain generator, a proportional and integration control processing block, a default spark timing processor, and an adaptive learning apparatus.

Abstract: A method of treating exhaust gases from a gasoline engine after cold-start using an exhaust gas aftertreatment system comprises adsorbing unburnt hydrocarbons (HC) from the engine exhaust gas with an HC trap, supplying heated ambient air to the exhaust gas stream downstream of the HC trap when the temperature of the HC trap is sufficient that trapped HC are desorbed therefrom and passing the air-enriched gas stream over a three-way catalyst (TWC). An exhaust gas aftertreatment system for a gasoline-fuelled engine (1) for performing the method according to the invention comprises a HC trap (5), a downstream secondary air injection point (8), means for supplying heated ambient air to the secondary air injection point (9), a TWC (7) downstream of the point of secondary air injection, and means in use for operating the heated air supply means when the temperature of the HC trap is sufficient that HC trapped thereon are desorbed therefrom.