Catalytic Converter Oxygen Reduction via Pre-Injection
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Solution Overview
Problem
The existing methods for internal combustion engines during overrun fuel cutoff mode lead to increased nitrogen oxide emissions due to excess oxygen storage in the catalytic converter, which hinders the conversion of nitrogen oxides into carbon monoxide and nitrogen, resulting in undesirable increases in hydrocarbon and carbon monoxide emissions.
Innovation Solution
A reduction method involving preinjection of fuel into the catalytic converter during the exhaust stroke, followed by subsequent fuel injections to react with stored oxygen, optimizing the oxygen storage surface and reducing nitrogen oxide emissions by delaying fuel feed restart and controlling the air-fuel ratio to substoichiometric or stoichiometric levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fuel is not injected during overrun fuel cutoff mode to save fuel, then fuel consumption is reduced, but excess oxygen accumulates in the catalytic converter which increases nitrogen oxide emissions
Solution Approach 1:
The patent applies preliminary action by injecting fuel into the cylinder before the overrun fuel cutoff mode begins (during the normal combustion phase), so that uncombusted fuel is carried into the catalytic converter and reacts with the excess oxygen that will accumulate during the subsequent fuel cutoff period. This pre-prepared fuel reduces nitrogen oxide emissions during the fuel-saving overrun mode without requiring fuel injection during the cutoff itself.
2Object-generated harmful factors
If fuel is injected during overrun fuel cutoff mode to reduce nitrogen oxide emissions, then nitrogen oxide emissions are reduced, but fuel consumption increases
Solution Approach 1:
The patent extracts the fuel injection action from the overrun fuel cutoff mode itself and places it in the phase immediately preceding the cutoff. By taking out the fuel injection from the cutoff period and positioning it before the cutoff begins, the system achieves nitrogen oxide reduction without consuming additional fuel during the overrun braking phase, thus resolving the contradiction between emission reduction and fuel economy.
3Quantity of substance
If the catalytic converter stores excess oxygen during overrun mode, then the oxygen storage capacity is utilized, but the conversion of nitrogen oxides to carbon monoxide and nitrogen is hindered
Solution Approach 1:
The patent converts the harmful effect of excess oxygen storage into a beneficial one by intentionally using that stored oxygen to oxidize uncombusted fuel hydrocarbons. The excess oxygen that would normally hinder nitrogen oxide conversion is instead directed to react with fuel carryover, transforming it from a problematic byproduct into an active reagent that reduces nitrogen oxide emissions through the sacrificial oxidation of hydrocarbons.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively reduces nitrogen oxide emissions by preconditioning the catalytic converter's oxygen storage surface, minimizing raw emissions of hydrocarbons, carbon monoxide, and carbon dioxide, while potentially leading to fuel savings through optimized engine operation.
Implementation Method 1
introduction of an injected fuel from the cylinder into the catalytic converter during an exhaust stroke of the first cylinder
Implementation Method 2
reducing the oxygen content in the catalytic converter... preconditioning the catalytic converter's oxygen storage surface
Implementation Method 3
the conversion of nitrogen oxides into carbon monoxide (CO) and nitrogen (N2)
Implementation Method 4
uncombusted hydrocarbon components (HCs) may be introduced into the catalytic converter and react with the stored oxygen before the first recombustion of the fuel takes place
Data Source
AI summary
A reduction method for a catalytic converter in an exhaust system of an internal combustion engine for reducing the oxygen content in the catalytic converter, in particular after an overrun fuel cutoff mode of the internal combustion engine, the method including first injection of fuel into a first cylinder, the first injection taking place after an ignition point in time of a compression stroke of a first working cycle of the cylinder and including an introduction of the injected fuel from the cylinder into the catalytic converter during an exhaust stroke of the first cylinder.