Internal-combustion-engine warm-up apparatus

1. An internal-combustion-engine warm-up apparatus comprising:

a post-processing apparatus that has a catalyst, and removes nitrogen oxides in exhaust gas discharged from an engine in an exhaust path where the exhaust gas passes;

a heater arranged upstream of the post-processing apparatus on the exhaust path;

a circulation path where air having passed through the post-processing apparatus is fed back to an upstream side of the heater;

a blower that feeds air heated by the heater to the post-processing apparatus;

a coolant flow path where a coolant of the engine flows;

a heat exchanger that warms the coolant in the coolant flow path by causing heat exchange between the heated air having passed through the post-processing apparatus and the coolant; and

a control apparatus that controls operation of the heater and the blower, wherein

in a state where the engine is stopped, the control apparatus causes the heater and the blower to operate, and causes the air heated by the heater to be supplied to the post-processing apparatus and the heat exchanger.

2. The internal-combustion-engine warm-up apparatus according to claim 1 , wherein the control apparatus causes the heater and the blower to operate in a case that a temperature of the catalyst in the post-processing apparatus is equal to or lower than a predetermined threshold.

3. The internal-combustion-engine warm-up apparatus according to claim 1 , wherein

the heat exchanger is arranged on the exhaust path,

the circulation path includes a first branch path that branches off from the exhaust path at a portion located upstream of the heat exchanger,

the internal-combustion-engine warm-up apparatus further comprises a first valve that is arranged at the portion where the first branch path branches off from the exhaust path, and switches between a state where the heated air flows through the first branch path, and a state where the heated air flows through the exhaust path, and

in a case that a temperature of the engine exceeds a predetermined threshold in a state where the heated air is being supplied to the post-processing apparatus and the heat exchanger, the control apparatus controls the first valve, and causes the heated air to flow through the first branch path, and to circulate in the circulation path.

4. The internal-combustion-engine warm-up apparatus according to claim 3 , wherein in a case that the temperature of the engine exceeds the predetermined threshold in a state where the heated air is being supplied to the post-processing apparatus and the heat exchanger, the control apparatus controls the first valve, and causes the heated air to flow only through the first branch path, and to circulate in the circulation path.

5. The internal-combustion-engine warm-up apparatus according to claim 3 , wherein

the heat exchanger is arranged on the exhaust path,

the circulation path includes a second branch path that branches off from the exhaust path at a portion located downstream of the heat exchanger,

the internal-combustion-engine warm-up apparatus further comprises a second valve that is arranged at the portion where the second branch path branches off from the exhaust path, and switches between a state where the heated air flows through the second branch path, and a state where the heated air flows through the exhaust path, and

the control apparatus controls the first valve and the second valve, switches the first valve to the state where the heated air flows through the exhaust path, and switches the second valve to the state where the heated air flows through the second branch path before the heater and the blower are caused to operate, and thereafter causes the heater and the blower to operate to supply the heated air to the post-processing apparatus and the heat exchanger.

6. The internal-combustion-engine warm-up apparatus according to claim 1 , wherein

the circulation path is a first circulation path where the air having passed through the post-processing apparatus is fed back to a position that is on the exhaust path, and is located downstream of a turbocharger and upstream of the heater, and

an air pump is arranged as the blower on the first circulation path.

7. The internal-combustion-engine warm-up apparatus according to claim 1 , wherein

the circulation path is a second circulation path where the air having passed through the post-processing apparatus is fed back to an intake path of a turbocharger, and

the heat exchanger is a low-pressure EGR cooler arranged on the second circulation path.