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US 2018/0023441 A1Published application
Exhaust gas control system for internal combustion engine and control method for internal combustion engine
AssigneeToyota Jidosha Kabushiki Kaisha
InventorArifumi MATSUMOTO
Life of this patent
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Abstract
In an exhaust gas control system for an internal combustion engine, addition valves which add an additive toward a first selective reduction NOx catalyst are provided in an exhaust passage on both of an upstream side and a downstream side of the SCR catalyst. In a case where a flow rate of exhaust gas flowing in the exhaust passage is equal to or lower than a predetermined flow rate, the additive is added from both addition valves to allow ammonia to be adsorbed onto the first selective reduction NOx catalyst.
Claims6
An exhaust gas control system for an internal combustion engine comprising:
- a first selective reduction NOx catalyst provided in an exhaust passage of the internal combustion engine,
- the first selective reduction NOx catalyst being configured to selectively reduce NOx in exhaust gas of the internal combustion engine with a reducing agent, and the reducing agent being ammonia;
- a first addition valve provided in the exhaust passage on an upstream side of the first selective reduction NOx catalyst in an exhaust gas flow direction,
- the first addition valve being configured to add an additive toward an end surface on the upstream side of the first selective reduction NOx catalyst, and
- the additive being one of the ammonia and a precursor of the ammonia;
- a second addition valve provided in the exhaust passage on a downstream side of the first selective reduction NOx catalyst in the exhaust gas flow direction,
- the second addition valve being configured to add the additive toward an end surface on the downstream side of the first selective reduction NOx catalyst;
- and
- an electronic control unit configured to control addition of the additive from the first addition valve and addition of the additive from the second addition valve,
- as a result of the electronic control unit determining that a flow rate of the exhaust gas flowing in the exhaust passage is equal to or lower than a predetermined flow rate when the ammonia is to be adsorbed onto the first selective reduction NOx catalyst, the electronic control unit being configured to allow the additive to be added from both of the first addition valve and the second addition valve.
7 more elements
A control method for an internal combustion engine,
- the internal combustion engine including an exhaust gas control system,
- the exhaust gas control system including a first selective reduction NOx catalyst provided in an exhaust passage of the internal combustion engine, a first addition valve provided in the exhaust passage on an upstream side of the first selective reduction NOx catalyst in an exhaust gas flow direction, a second addition valve provided in the exhaust passage on a downstream side of the first selective reduction NOx catalyst in the exhaust gas flow direction, and an electronic control unit configured to control addition of an additive from the first addition valve and addition of the additive from the second addition valve,
- the first selective reduction NOx catalyst being configured to selectively reduce NOx in the exhaust gas of the internal combustion engine with a reducing agent, and
- the reducing agent being ammonia,
- the first addition valve being configured to add the additive toward an end surface on the upstream side of the first selective reduction NOx catalyst, and
- the second addition valve being configured to add the additive toward an end surface on the downstream side of the first selective reduction NOx catalyst, and
- the additive being one of the ammonia and a precursor of the ammonia,
- the control method comprising:
- determining, by the electronic control unit, whether or not an exhaust gas flow rate is equal to or lower than a predetermined flow rate;
- and
- adding the additive onto the first selective reduction NOx catalyst from both of the first addition valve and the second addition valve, as a result of the electronic control unit determining that the flow rate of the exhaust gas flowing in the exhaust passage is less than the predetermined flow rate when the electronic control unit allows the ammonia to be adsorbed onto the first selective reduction NOx catalyst.
8 more elements
Dependencies are inferred from the claim text.