Abstract:
A method of controlling the mass of air and fuel delivered to an internal combustion engine per cylinder per cycle by first determining the required fuel per cycle for the existing engine operating conditions, and then setting the air supply to the engine to provide the required air/fuel ratio for the determined fuel per cycle requirement. Thereafter, determining the actual air supply to the engine, and adjusting the fuel per cycle so the actual air/fuel ratio is greater or less than predetermined limits of the required air/fuel ratio. A look-up map can be provided in an electronic engine management system with preset air/fuel ratios against engine speed and load. The map is arranged with the predetermined limits of the required air/fuel ratio selected to prevent a specific condition such as engine misfire or for catalyst and/or emission considerations.
Abstract:
A method of control of the supply of lubricating oil to a two stroke cycle internal combustion engine comprising supplying fuel to a fuel injector from a fuel reservoir having a fuel capacity greater than the maximum fuel requirement of the engine per cycle. The fuel in the reservoir being maintained at a substantially steady pressure. Delivering oil to the engine by a positive displacement pump having a delivery capacity per pump cycle greater than the maximum oil requirement of the engine per cycle. The oil pump being activated in response to the consumption of fuel from the fuel reservoir to maintain a substantially uniform predetermined ratio between the fuel consumption rate and the oil delivery rate.
Abstract:
A two stroke cycle engine cylinder block (9) has exhaust ports (14) controlled by power valves (not shown) which rotate on an axis extending longitudinally of the block (9). Along this axis the block (9) has a plurality of aligned recesses in which are located bearing members (24) for the power valves. Bores (25) in each bearing member (24) are axially aligned and the bearing members (24) immobilely retained in the aligned recesses by assembly of the exhaust manifold (16). Spigots on the power valves are received in the bores (25) and coupled together so that the power valves rotate in unison.
Abstract:
A method of operating a fuel system having a fuel pump (15) to supply fuel to a fuel metering apparatus (23) operable to provide metered quantities of fuel for injection to an engine, and an electronic controller (22) responsive to a plurality of input signals to determine the engine fuel demand and to control the activation of the fuel metering apparatus (23) to deliver a quantity of fuel to meet said fuel demand. The method comprising maintaining a fuel supply to said fuel metering apparatus (23) within predetermined fuel pressure or fuel level parameters, and cyclically operating said fuel pump (15) to maintain said fuel supply within said parameters. Further providing a signal from a sensor (18) to the electronic controller (22) indicative of the pressure of the fuel supply at the fuel metering apparatus (23) as one of said input signals to be processed by the electronic controller (22) in the control of the fuel metering apparatus (23). The pump (15) preferably provides fuel to a closed chamber that acts in the manner of an accumulator (16), and the pressure sensor (18) provides an input signal to the electronic controller (22) indicative of the pressure of the fuel available to the fuel metering apparatus (23) from the accumulator (16). Alternatively, the chamber may maintain the fuel between predetermined levels at a substantially steady or variable pressure.
Abstract:
A method and apparatus for metering liquid fuel for delivery to an engine including delivering during each cycle a predetermined quantity of liquid fuel into a control chamber (71) charged with compressed gas, and thereafter, adjusting the quantity of fuel in the control chamber (71) in accordance with the engine load and/or speed to the required quantity per cycle, and discharging the adjusted quantity of fuel from the control chamber (71) to an injection chamber (70) charged with compressed air for delivery to the engine combustion chamber. Conveniently, as the quantity of fuel is maintained in said control chamber (71) under pressure, the adjustment of the quantity of fuel is effected by opening a bleed valve (73) for a time period determined by the quantity of fuel required to be retained for delivery to the engine. A method and apparatus for metering fluids for cyclic delivery in variable discrete quantities are also disclosed.
Abstract:
A method of operating a two stroke cycle crankcase scavenged internal combustion engine, comprising selectively delivering exhaust gas from a location downstream of the engine exhaust port to the engine crankcase to be delivered together with air in the crankcase to the engine combustion chamber. The quantity of exhaust gas delivered to the crankcase each engine cycle is controlled according with engine operating conditions and the rate of supply of exhaust gas to the crankcase is controlled relative to engine operating conditions such as by an ECU managed valve that responds to engine operating conditions such as load, speed and temperature. The exhaust gas is admitted to the crankcase during a period when the pressure in the crankcase is below that of the available exhaust gas.