Power plants – Internal combustion engine with treatment or handling of... – By means producing a chemical reaction of a component of the...
Reexamination Certificate
2002-11-22
2004-11-16
Richter, Sheldon J (Department: 3748)
Power plants
Internal combustion engine with treatment or handling of...
By means producing a chemical reaction of a component of the...
C060S289000, C060S290000, C060S307000, C060S396000, C060S397000
Reexamination Certificate
active
06817173
ABSTRACT:
STATE OF THE ART
The invention relates to a method and an internal combustion engine suitable for carrying out this method, in which an intake airflow for the internal combustion engine and a secondary airflow for injection into the exhaust system of the internal combustion engine are simultaneously adjusted with respect to the required mass flow.
Apparatus of the kind referred to above are known, e.g., from WO 97/38 212. According to FIG. 8 of this document a secondary air injection system for an internal combustion engine is presented, which consists of a turbine unit 114 and a compressor 113. The turbine is driven through a bypass duct which is arranged parallel to the throttle valve 115 in the air intake tract. In the bypass duct to the turbine there is furthermore disposed at least one throttling member 120. The simultaneous adjustment of the air intake stream and secondary air stream is performed by the interaction of throttle valve 115 and throttling member 120. Thus on the one hand the power of the turbine 114, and thus also the secondary air delivered by the compressor 113, can be adjusted, and on the other hand the delivered intake air stream can be adjusted as an addition of the air streams by the throttling member 120 and the throttle valve 115.
For the optimum adjustment of the two air streams the complex actions of the internal combustion engine must be known. On this basis the current air requirement in the intake tract of the internal combustion engine and in the exhaust system can be determined. The air requirement of the internal combustion engine is dependent, for example, on the load state, but also on the desired kind of operation, e.g., the combustion of the fuel with excess oxygen or oxygen deficiency. Secondary air is introduced into the exhaust system in the cold-start phase of the motor, for example. This is intended to oxidize incompletely burned exhaust components and to additionally heat by this exothermic reaction the catalyst that follows in the exhaust system. Thus, during the cold-start phase the pollutant discharge is reduced, and the cold-start phase is shortened, since the catalyst goes into action sooner due to the heating.
In the introduction of secondary air a certain air ratio must be established so that the emissions reduction will operate. In case of too much secondary air the exhaust gas is cooled too strongly without the oxidation of the additional exhaust components. In the case of too little secondary air not enough oxygen is available to oxidize the exhaust components.
One object of the invention is to provide a method that will enable a satisfactory adjustment of the secondary airflow and the intake airflow for the internal combustion engine by means of simple principles. A further object of the invention is to provide suitable devices for this method.
ADVANTAGES OF THE INVENTION
The method of the invention is appropriate in a known manner for the simultaneous adjustment of the intake air stream of the internal combustion engine and of the secondary air stream in the exhaust system of the internal combustion engine. The adjustment of the air streams is performed through a variation of the mass flow. In the air intake tract of the internal combustion engine a throttle valve is contained, the latter being able to affect only the mass flow of the intake air in the intake tract. When the intake air stream is adjusted, allowance must be made for the ambient air flow which is branched off to drive the turbine ahead of the throttle valve and to be returned to the intake tract behind the throttle valve. The turbine drives a compressor which produces the secondary air stream. The latter is fed to the exhaust system, and its injection ahead of the catalyst, for example, is desirable in order to achieve the previously described effects for the exhaust gas in the cold starting phase of the engine.
The invention is characterized in that at least when the internal combustion engine is idling the throttle valve assumes a position established for this state. This is done in view of the fact that, when the internal combustion engine is idling the need for air is known. By putting the throttle valve in a set position and putting the known air intake performance of the internal combustion engine at idle, it is thus possible simultaneously to achieve a defined turbine power. The throttle valve must be adjusted such that the air intake stream which sweeps past the throttle valve when added to the ambient air stream results in just the amount of air necessary for the idling of the internal combustion engine. In this way it can be brought about that, in this state of operation, the internal combustion engine runs with the required rotatory speed. Fluctuations in the amount of intake air delivered would result in an irregular speed of the internal combustion engine.
The valve position desirable for the idling speed, in relation to the air stream required for ordinary driving, must be determined for the internal combustion engine. For this purpose a throttling means can additionally be used, which is arranged in the bypass line and by means of which the air stream at the turbine can be influenced. The known conditions when the internal combustion engine is idling render unnecessary therefore a regulation or control of the rate of flow of the intake air. In this state of operation, slight departures from the intake air rate of flow that is actually desired are especially critical, since the internal combustion engine reacts to them immediately with a change in rpm. In other operating conditions, departures from the desired amounts of air intake and secondary air flows are of less importance. For these can be established in the bypass duct without providing any additional adjusting means such as the throttle valve and the throttling device as will be explained more precisely below. This has a positive effect on the economy of the proposed method, since additional regulating means become superfluous. The throttle valve setting can be operated, for example, through the motor control that is present anyway.
According to an additional embodiment of the invention, the established position of the throttle valve in the idling state is precisely when it is closed. In this case the air intake for the internal combustion engine is supplied exclusively through the bypass line. In that case the turbine can be used as the means for controlling the amount of intake air during idling. This becomes possible because the air throughput by the turbine is dependent upon the power consumed by the compressor, although in this case care must be taken that the compressor power is simultaneously affected by the mass flow of the secondary air.
According to an improvement of the invention, the throttle valve is to remain in the closed position as long as the required bypass air flow of the internal combustion engine is below the maximum possible at the turbine. Because this is the condition required that the air demand of the internal combustion engine can be covered exclusively through the bypass duct. In these circumstances of operation the maximum possible turbine power is always available. It can thus be converted to the greatest possible secondary air stream, which increases the possibilities for the variation of the amount of secondary air fed into the exhaust system.
If the turbine output is too great in the case of the complete closure of the throttle valve, to achieve a satisfactory setting of the secondary air flow, a throttle valve can be provided in the secondary air duct, according to a special embodiment of the invention. This permits reducing the secondary air flow whenever the mass of air being delivered is too great for the momentary state of operation of the internal combustion engine. This effect can advantageously also achieved by an additional duct which bypasses the compressor. This is made so as to be throttled and it can also be completely shut off. In the case of an opening, an air stream is produced in the additional duct which is opposed to the flow deliv
Fischer Jochem
Hummel Karl Ernst
Paffrath Holger
Crowell & Moring LLP
Filterwork Mann & Hummel GmbH
Richter Sheldon J
LandOfFree
Method and device for simultaneous regulation of an intake... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for simultaneous regulation of an intake..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for simultaneous regulation of an intake... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3345803