Injector control for a selective catalytic reduction system
AssigneePACCAR Inc
InventorsNathan J. Kaemingk, Michael Gerty
Life of this patent
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Abstract
Systems and methods are provided for controlling the amount and timing of nitrogen oxide reductant injected during a given injection cycle into an exhaust system of a vehicle as part of a selective catalytic reduction system. The amount of reductant injected is determined by at least one computational model that accounts for the growth of liquid and/or solid reductant film growth on the interior of the exhaust system. The model determines reductant injection characteristics (e.g., amount, timing, etc.) that reduce and/or eliminate reductant films on the interior of the exhaust system. Exemplary inputs into the model include exhaust temperature, exhaust flow, and the amount of reductant injected in a previous injection cycle.
Claims19
A method of using an on-board vehicle computing system to control a flow rate of reductant solution injected by an injector into an exhaust flow from an engine producing nitrogen oxides towards a catalyst, the method comprising:
- (a) determining, by the on-board vehicle computing system, a first value of a first operating parameter;
- (b) determining, by the on-board vehicle computing system, a first value of a second operating parameter;
- (c) determining, by the on-board vehicle computing system, a first injector flow rate parameter corresponding to the flow rate of reductant solution being injected into the exhaust flow by the injector;
- (d) determining, by the on-board vehicle computing system, a first reductant solution puddle size based on at least the determined first injector flow rate parameter;
- (e) determining, by the on-board vehicle computing system, a reductant solution puddle delta based on at least one of the first injector flow rate and the determined first reductant solution puddle size;
- (f) determining, by the on-board vehicle computing system, a second injector flow rate parameter of the reductant solution based on at least the determined first injector flow rate parameter and the determined reductant solution puddle delta;
- and
- (g) adjusting, by the on-board vehicle computing system, the flow rate of the reductant solution injected by the injector to a flow rate corresponding to the determined second injector flow rate parameter.
A non-transitory computer-readable medium having computer-executable instructions stored thereon for controlling a flow rate of a reductant solution into an exhaust flow from an engine producing nitrogen oxides towards a catalyst with an injector, wherein the instructions, in response to execution by one or more on-board vehicle computing devices, cause the one or more on-board computing devices to:
- determine an amount of a reductant for reacting with nitrogen oxides, the reductant solution to be injected by solution an injector into an exhaust flow from an engine producing nitrogen oxides towards a catalyst, the one or more computing devices using the steps:
- (a) receive a first value of a first operating parameter input;
- (b) receive a first value of a second operating parameter input;
- (c) receive a first injector flow rate parameter corresponding to the flow rate of reductant solution injected by the injector into the stream of exhaust;
- (d) determine a first reductant solution puddle size based on at least the received injector flow rate parameter;
- (e) determine a reductant solution puddle delta based on at least the first reductant solution puddle size based on at least the determined first reductant solution puddle size;
- (f) determine a second injector flow rate parameter of the reductant solution based on at least the determined reductant solution puddle delta and the received first injector flow rate parameter;
- and
- (g) adjust the flow rate of reductant solution injected by the injector into the stream of exhaust corresponding to the second injector flow rate parameter.
A system for injecting a determined amount of a reductant solution for reacting with nitrogen oxides into an exhaust flow from an engine producing nitrogen oxides, the system comprising:
- (a) an injector configured to inject the reductant solution into the exhaust flow;
- (b) a first sensor configured to measure a first operating parameter of the exhaust flow;
- (c) a second sensor configured to measure a second operating parameter of the exhaust flow;
- and
- (d) a wall wetting controller configured to:
- determine a first injector flow rate;
- determine a first reductant solution puddle size based on at least the first injector flow rate;
- determine a reductant solution puddle delta based on the first injector flow rate and the determined first reductant solution puddle size;
- determine a second injector flow rate based on the first injector flow rate and the determined reductant solution puddle delta;
- and
- transmit a first control signal to the injector, wherein the first control signal is based on the second injector flow rate, and wherein the injector is configured to adjust a flow rate of the reductant solution injected into the exhaust flow to the second injector flow rate in response to receiving the first control signal.
Dependencies are inferred from the claim text.