Methods and system are provided for indicating whether a variable orifice valve positioned in a fuel vapor recovery line of a vehicle fuel system is degraded. In one example, a method may include actively manipulating a pressure in the fuel system during a refueling event, and indicating whether the variable orifice valve is degraded based on a loading rage of a fuel vapor storage canister with fuel vapors while the pressure is actively manipulated. In this way, it may be determined as to whether the variable orifice valve is stuck in a high-flow or a low-flow position such that mitigating action may be taken to reduce or avoid release of undesired evaporative emissions to atmosphere.

An EGR valve is provided in an EGR passage circulating a part of an exhaust gas of an exhaust pipe in an intake pipe as an EGR gas, the EGR valve adjusting an EGR gas amount flowing in the EGR passage when an engine is in an EGR region, a differential pressure device is provided in the intake pipe, the differential pressure device adjusting a differential pressure of the EGR valve, a control unit is provided to control the EGR valve and the differential pressure device, and the EGR control method includes switching whether to adjust the EGR gas amount using the EGR valve and the differential pressure device or to adjust the EGR gas amount using the EGR valve only on the basis of an exhaust gas pressure of an inlet portion of the EGR passage.

An EGR valve is provided in an EGR passage circulating a part of an exhaust gas of an exhaust pipe in an intake pipe as an EGR gas, the EGR valve adjusting an EGR gas amount flowing in the EGR passage when an engine is in an EGR region, a differential pressure device is provided in the intake pipe, the differential pressure device adjusting a differential pressure of the EGR valve, a control unit is provided to control the EGR valve and the differential pressure device, and the EGR control method includes switching whether to adjust the EGR gas amount using the EGR valve and the differential pressure device or to adjust the EGR gas amount using the EGR valve only on the basis of an exhaust gas pressure of an inlet portion of the EGR passage.

An energy recovery system for an engine system is disclosed. The engine system includes an engine, an exhaust conduit configured to receive exhaust gases discharged from the engine, and a first turbocharger coupled to the exhaust conduit to receive exhaust gases from the engine and provides compressed air to the engine. The energy recovery system includes a bypass conduit, a second turbocharger, and an accumulator. The bypass conduit is coupled to the exhaust conduit upstream of the first turbocharger, and facilitates a portion of exhaust gases from the exhaust conduit to bypass the first turbocharger. The second turbocharger is coupled to the bypass conduit, and is driven by the portion of exhaust gases bypassing the first turbocharger to compress air received from an ambient to a first pressure. The accumulator is in fluid communication with the second turbocharger, and stores air received from the second turbocharger at the first pressure.

An engine system includes an internal combustion engine with two sets of cylinders, a turbocharger, two exhaust conduits providing fluid communication between the turbocharger and an exhaust of the cylinders, and an exhaust gas recirculation system including a recirculation valve. Two proportional exhaust valves are adapted to control a flow of exhaust gas in the two exhaust conduits. An actuator includes an output component operating the recirculation valve and the two exhaust valves. In a neutral position, the two exhaust valves are open and the recirculation valve is closed. A first movement of the output component, from its neutral position towards a first position, open the recirculation valve and close a first of the two exhaust valve. A second movement, from the first position and in the same direction as the first movement, close the second exhaust valve and hold open the recirculation valve and closed the first exhaust valve.

An intake control method for an internal combustion engine equipped with a low-pressure EGR system includes setting a target intake pressure, which is a target value of an intake pressure in an intake passage between a negative pressure generating valve and an intake throttle valve, necessary for performing EGR control in a state of an exhaust pressure determined for each operating point, setting a target total opening area, which is a sum of a target opening area of an EGR valve and a target opening area of the negative pressure generating valve, on the basis of the target intake pressure, a target fresh air amount, and a target EGR gas amount, setting a target EGR valve opening area, which is an opening area of the EGR valve for achieving the target EGR gas amount, assuming that the negative pressure generating valve is fully open, and setting a value obtained by subtracting the target EGR valve opening area from the target total opening area to be a target negative pressure generating valve opening area, which is a target value of an opening area of the negative pressure generating valve.

A power system includes an intake arrangement and a compression ignition engine including piston-cylinder sets. Each piston-cylinder set includes: a cylinder; a piston positioned within the cylinder to form a combustion chamber in between; an intake valve configured to open and close the intake port; an exhaust valve configured to open and close the exhaust port; and a fuel injector. During an exhaust stroke, the exhaust valve is opened to enable exhaust gas to flow out; during an initial portion of an intake stroke, the intake valve is opened to enable the intake air to flow into the combustion chamber, and during a further portion of the intake stroke, the intake valve is closed and the exhaust valve is opened to enable a portion of the exhaust gas to flow back into the combustion chamber in order to create thermally stratified layers of intake gas and exhaust gas.

A power system includes an intake arrangement and a compression ignition engine including piston-cylinder sets. Each piston-cylinder set includes: a cylinder; a piston positioned within the cylinder to form a combustion chamber in between; an intake valve configured to open and close the intake port; an exhaust valve configured to open and close the exhaust port; and a fuel injector. During an exhaust stroke, the exhaust valve is opened to enable exhaust gas to flow out; during an initial portion of an intake stroke, the intake valve is opened to enable the intake air to flow into the combustion chamber, and during a further portion of the intake stroke, the intake valve is closed and the exhaust valve is opened to enable a portion of the exhaust gas to flow back into the combustion chamber in order to create thermally stratified layers of intake gas and exhaust gas.

An exhaust gas recirculation system for gasoline engine includes a first exhaust gas return tube, a high-pressure by-pass tube, a second exhaust gas return tube and an EGR control unit. The first exhaust gas return tube includes a hot end, a cold end, a high-pressure EGR cooler, and a high-pressure EGR valve. The high-pressure by-pass tube connected with the first exhaust gas return tube in parallel has a high-pressure EGR by-pass valve. The second exhaust gas return tube has a hot end, a cold end, a low-pressure EGR cooler, a low-pressure EGR valve and a low-pressure EGR pump. The EGR control unit is electrically connected with the high-pressure EGR valve, the high-pressure EGR by-pass valve, the low-pressure EGR valve and the low-pressure EGR pump respectively. Different EGR recirculation manners can be chosen under different loads and different running conditions of the gasoline engine to meet different demands under different conditions.

An exhaust gas recirculation system for gasoline engine includes a first exhaust gas return tube, a high-pressure by-pass tube, a second exhaust gas return tube and an EGR control unit. The first exhaust gas return tube includes a hot end, a cold end, a high-pressure EGR cooler, and a high-pressure EGR valve. The high-pressure by-pass tube connected with the first exhaust gas return tube in parallel has a high-pressure EGR by-pass valve. The second exhaust gas return tube has a hot end, a cold end, a low-pressure EGR cooler, a low-pressure EGR valve and a low-pressure EGR pump. The EGR control unit is electrically connected with the high-pressure EGR valve, the high-pressure EGR by-pass valve, the low-pressure EGR valve and the low-pressure EGR pump respectively. Different EGR recirculation manners can be chosen under different loads and different running conditions of the gasoline engine to meet different demands under different conditions.