Methods and systems are provided for a coolant system. In one example, a method may include diagnosing a condition of a pump of the coolant system based on a temperature change of coolant. The diagnostic may determine if the pump is stuck on or off.

An engine system of the present disclosure includes an engine configured to drive a plurality of pistons by burning a mixture of air and gas, an air supply pipe through which the air supplied to the engine flows, a supercharger configured to compress the air flowing through the air supply pipe, a gas supply pipe through which the gas supplied to the engine flows, and a mixer configured to mix the air that has passed through the supercharger and the gas. The mixer has a venturi tube shape in which a cross-sectional area of a flow path decreases and expands in a flow direction of the air that has passed through the supercharger, and the gas supply pipe is connected to a portion of the mixer where the cross-sectional area of the flow path in the mixer is decreased.

A system includes an engine defining a water jacket fluidly coupled to a heat exchanger. An exhaust manifold defines an exhaust manifold cooling passage. A pump is fluidly coupled to the water jacket, and to each of the heat exchanger and the exhaust manifold cooling passage. An engine cooling circuit includes the water jacket, the heat exchanger, and the pump. An exhaust cooling circuit is selectively fluidly coupled to the engine cooling circuit. The exhaust cooling circuit includes the water jacket, the exhaust manifold cooling passage, and the pump. A control valve includes an inlet fluidly coupled to a first portion of the water jacket. A first outlet is fluidly coupled to a second portion of the water jacket. A second outlet is fluidly coupled to the exhaust cooling circuit. The control valve is structured to selectively control flow of coolant fluid through the second outlet.

An outboard motor is provided with an upper separator disposed on the lower side of an oil case for storing a lubricating oil of an engine, and an extension case which is separably connected on the lower side of the upper separator. The upper separator has a central exhaust passage through which exhaust gas flows, and a cooling water flow part through which cooling water flows on the outside of the central exhaust passage, the central exhaust passage and the cooling water flow part forming an integrated structure. The exhaust gas and the cooling water are caused to mix in the extension case.

A control valve 8 according to the present disclosure includes a casing 21 in which an outlet for a liquid is formed and the liquid is accommodated, a rotor 22 rotatably accommodated in the casing 21 and having a communication port communicating with the outlet, and a sliding ring 131 having a sliding surface 141a sliding on an outer surface of the rotor in a state of being disposed inside the outlet and causing the outlet and the communication port to communicate with each other according to a rotation position of the rotor 22, in which a liquid holding portion for holding the liquid between the sliding surface 141a and the liquid holding portion is provided on the outer surface of the rotor 22, and the liquid holding portion has a recessed portion for accommodating the liquid.

A control valve includes a casing, a valve body, seal tube members, a fuel passage, and a thermostat. The casing has an inflow port and a plurality of outflow ports. The valve body is rotatably disposed inside the casing, and valve holes are formed in a circumferential wall portion. The seal tube members communicate with the outflow ports, abut an outer circumferential surface of the circumferential wall portion, and are opened and closed by corresponding valve holes. Thermostat opens and closes the fuel passage in response to a detected temperature. A communication groove is formed on an inner circumferential surface of the casing. The communication groove causes the inflow port and an upstream portion of the fuel passage to communicate with each other by partially expanding a gap between the circumferential wall portion and the casing.

A cooling system of a hybrid vehicle include an engine, a drive motor, a main water pump, a cooling line, a heat-exchange line, a heater line on which a heater and an exhaust heat recovery device are provided, a coolant control valve unit selectively supplying coolant to the cooling line, the heat-exchange line and the heater line, a bypass line connecting the rear of the exhaust heat recovery device and the front of the heater, an auxiliary water pump that selectively supplies coolant from the exhaust heat recovery device to the front of the heater, a state measurement unit that measures an operation state of the vehicle and outputs a corresponding signal, and a controller configured for controlling operation of the engine, the drive motor, the main water pump, the coolant control valve unit and the auxiliary water pump according to the output signal of the state measurement unit.

A vehicle cooling device includes a first heat exchanger and a second heat exchanger. The first heat exchanger is a water-cooled intercooler that is configured to cool supercharged intake air. The second heat exchanger is a water-cooled EGR gas cooler that is configured to cool EGR gas. The first heat exchanger and the second heat exchanger are arranged in series on a cooling water circuit such that cooling water flowing out of the first heat exchanger flows into the second heat exchanger. The second heat exchanger is arranged in a position relatively lower than a height position of the first heat exchanger when the cooling device has been installed in a vehicle. Due to this height difference, the cooling water in the second heat exchanger has high pressure, and boiling of the cooling water is suppressed.

An engine system is provided, including an engine having a water jacket, a circulation system that circulates coolant through the water jacket, and a controller. The circulation system includes a radiator passage including a heat exchanger, a bypass passage bypassing the heat exchanger, a flow rate control device, and a thermally-actuated valve connected to the radiator passage and that opens to allow the coolant to pass through the heat exchanger. When an engine load is below a first load, the controller controls the flow rate control device to adjust the coolant flow rate flowing through the water jacket according to the load, by closing the radiator passage and adjusting the coolant flow rate flowing through the bypass passage. When the load is above the first load, the controller controls the flow rate control device so that the coolant flows through each of the radiator passage and the bypass passage.

An engine cooling system is provided, which includes a water jacket through which coolant flows, a heat exchanger that cools the coolant, a first bypass passage that bypasses the heat exchanger and recirculates the coolant to the water jacket, a radiator passage that recirculates the coolant to the water jacket via the heat exchanger, and a flow control device that is installed at a location where a coolant passage branches into the first bypass passage and the radiator passage and performs a water flow control to adjust a coolant amount flowing into the water jacket by adjusting a coolant amount flowing through the first bypass passage. A thermally-actuated valve connected with the radiator passage via a second bypass passage is provided to the first bypass passage, and when this valve opens, the coolant flowing through the first bypass passage flows into the radiator passage through the second bypass passage.