INTAKE AND EXHAUST SYSTEM

An intake and exhaust system includes an engine, an exhaust flow passage, a catalyst, and a control apparatus. The exhaust flow passage is coupled to the engine. The catalyst is disposed in the exhaust flow passage and configured to purify exhaust gas. The control apparatus includes one or more processors, and one or more memories coupled to the one or more processors. The one or more processors are configured to: before the engine is started up, execute scavenging control that causes the exhaust gas remaining in the engine and the exhaust flow passage to flow to pass through the catalyst before being discharged; and before the engine is started up, execute warming control that warms up the catalyst, based on a degree of purification of the exhaust gas by the catalyst during execution of the scavenging control.