An aircraft propulsion system comprising a reciprocating liquid cooled engine housed within the fuselage driving twin fuselage mounted ducted-fans is disclosed. The propulsion system may be liquid cooled with a liquid cooled exhaust and at least one turbocharger. The ducted-fans may run fan blade tip speeds of up to 97% Mach driven by a near constant RPM engine through a continuously variable transmission. The propulsion system may be low noise and may meet environmental standards typical in the automotive industry.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

The exhaust gas recirculation (EGR) system provided herein utilizes a crossover (X) valve that is selectively activated at the direction of the electronic control module (ECM) to mix the high temperature (HT) and low temperature (LT) circuits of the EGR system under certain predetermined operating conditions. Thus, HT circuit fluid (at engine temperatures) is selectively fed into the LT circuit fluid (at ambient temperatures) to heat certain LT circuit components that are normally cooled by the LT circuit before starting the low pressure (LP) EGR in certain cold cycles. When this heating is finished, the X valve is closed to provide normal HT circuit/LT circuit fluid separation. The X valve can be controlled using a rotational actuator or the like. To avoid exposing the LT circuit to the high revolution-per-minute (RPM) operating conditions of the HT circuit, a HT bypass mechanism is provided.

Systems and methods are provided for management of a thermal system. A system for thermal management includes a thermal system with fluid conduits. A sensor is disposed to monitor an input parameter state of the thermal system. An actuator is configured to vary a flow in the fluid conduits. A controller is configured to receive a signal representative of the input parameter state; process an actuator state through a flow model of the thermal system to obtain an existing flow in the fluid conduits; process the existing flow through a thermal model of the thermal system to determine an input that reduces an error between a desired parameter state and the input parameter state; process the input through an inverse flow model to convert the input to a desired actuator state; and position the actuator in the desired actuator state.

A cylinder head cooling system may include a main water jacket formed on a cylinder head, an exhaust port formed on the cylinder head, and an exhaust port water jacket formed to cool the exhaust port, wherein, the exhaust port water jacket includes an inlet that communicates with the main water jacket and a plurality of outlets separated from the main water jacket.

A two-stroke engine comprises a first oiling system and a second oiling system. The first oiling system includes a low-pressure pump that distributes oil from a first oil tank to the two-stroke engine. The second oiling system includes a pump mechanically coupled to a crankshaft of the two-stroke engine, wherein the pump distributes oil from a second oil tank to an accessory at a pressure greater than the first oil pressure, wherein oil distributed to the accessory is returned to the second oil tank.

A system for controlling fluid temperature in a thermal system includes a heat source, a heat sink coupled to the heat source, a first heat exchanger and a second heat exchanger, a first expansion valve configured to regulate the flow of coolant between the heat source and the first heat exchanger, a second expansion valve configured to regulate the flow of coolant between the heat source and the second heat exchanger, and a controller. The controller is configured to determine an operating condition of the thermal system and generate a first control signal to control the first and second expansion valves to direct the flow of coolant to the first and second heat exchangers. The first and second expansion valves are arranged in parallel to recover heat rejected from the coolant and distribute the recovered heat to the first and second heat exchangers.

Methods and systems are provided for a valve for controlling the flow of a fluid medium in a coolant circuit of an internal combustion engine. The valve is configured to react to the temperature of the coolant via an expansion element and to the charge pressure in the intake tract via a pressure-sensitive actuator.

In a cooling apparatus including a high-temperature-side radiator in a high-temperature-side cooling circuit supplying a high-temperature coolant to a cylinder head, a low-temperature-side radiator in a low-temperature-side cooling circuit supplying a low-temperature coolant to an intercooler, and an electronic control unit, the high-temperature-side cooling circuit includes a first coolant passage where the high-temperature coolant flows around an exhaust port, a second coolant passage where the high-temperature coolant flows through the cylinder head without flowing around the exhaust port, and a flow rate adjustment valve adjusting a flow rate of the high-temperature coolant flowing through the first coolant passage. The electronic control unit executes a response improvement process for controlling the flow rate adjustment valve to reduce the flow rate of the high-temperature coolant flowing through the first coolant passage, and for controlling the low-temperature-side pump to increase a flow rate of the low-temperature coolant circulating through the low-temperature-side cooling circuit.

A method for thermal management of a motor vehicle engine includes one or more of the following: determining a current lube oil temperature; determining a lube oil temperature for optimal friction; turning on piston cooling jets based on the current lube oil temperature and the lube oil temperature for optimal friction; and turning off the piston cooling jets.