Abstract: A method for generating cavitation resistance in a liquid, a portion of which can be in contact with a surface is disclosed. The disclosed method can be carried out by pressure-treating the liquid, the liquid portion in contact with the surface, and/or the surface for a sufficient time to develop resistance to cavitation. The disclosed method can be carried out when the surface is made of a material having a surface roughness that is greater than the rc of the liquid. Suitable surfaces include borosilicate glass, drawn glass, copper, lead, steel, cast iron, metal alloys and concrete. The surfaces can be ship and boat propeller surfaces, the interior of fuel lines and fuel storage containers or any other surface where cavitation can occur.

Abstract: An assembly is provided that includes a shaft, a bearing, a stator seal element, a rotor seal element and a shield. The shaft extends along an axis. The bearing supports the shaft and receives lubrication fluid. The stator seal element circumscribes the shaft. The rotor seal element is mounted on the shaft axially between the bearing and the stator seal element. The rotor seal element forms a seal with the stator seal element. The shield substantially prevents the lubrication fluid from traveling axially away from the bearing onto the rotor seal element.

Abstract: An environmental control power generation system is provided. The system may include a turbine and a generator. The system may be configured to provide air form a high pressure bleed port and/or a low pressure bleed port to the turbine. The turbine may be configured to reduce the pressure of the supplied air and generate power through the generator. The power may be supplied to an aircraft power distribution system.

Abstract: A combustor is provided with a plurality of fuel nozzles that extend in an axial direction of a combustor main body and are capable of injecting fuel from injection holes which are disposed on the combustion chamber side. The combustor is provided with a phase adjusting unit which partially changes the flow path cross-sectional area of at least one fuel nozzle in the axial direction such that phases of flow rate fluctuation of fuel do not match with respect to at least two fuel nozzles among the plurality of fuel nozzles.

Abstract: Methods and systems are provided for operating an engine in a two-valve diagonal blow-through mode during which a majority of blow-through is directed via a first intake valve positioned diagonally across a first exhaust valve in order to increase a distance of flow path from the intake valve to the exhaust valve.

Abstract: An internal combustion engine has at least one engine cylinder which is closed at an end by a cylinder head and within which a piston reciprocates. The cylinder head has a plunger receptacle and the piston has a plunger which, when the piston is reciprocating within the engine cylinder over an engine cycle's range between BDC and an intermediate position spaced from both TDC and BDC, fully opens the plunger receptacle to the interior of the engine cylinder, and which, when the piston is reciprocating over an engine cycle's range between the intermediate position and TDC position, enters the plunger receptacle to compress an air-fuel mixture at higher compression ratio in the plunger receptacle where it is ignited and subsequently used to ignite the rest of the mixture during piston downstroke.

Abstract: Various systems and methods are described for controlling engine operation. One method comprises, during a first variable displacement engine (VDE) mode in an engine having four cylinders, deactivating a first cylinder of the four cylinders and firing a second, third, and fourth cylinder of the four cylinders, each firing event separated by 240 degrees of crank angle (CA). The engine may be operated in a non-VDE mode by activating the first of the four cylinders and firing the first cylinder between the third and fourth cylinders.

Abstract: Methods and systems are provided for controlling engine operation. One method comprises during a first condition, operating the engine with a single cylinder deactivated and remaining cylinders activated with a first intake duration, and during a second condition, operating the engine with the single cylinder deactivated and the remaining cylinders activated with a second intake duration. The method further comprises during a third condition, operating the engine with all cylinders activated.

Abstract: An object is to prevent an engine from entering an unstable combustion state such as misfire upon recovery, by halting or reducing gas fuel for a cylinder in which knocking is occurring, and then increasing the gas fuel again to appropriately perform a recovery control upon recovery to the optimum operation. A combustion control device for a gas engine includes: a knocking determination unit 49 configured to determine occurrence of knocking of each of cylinders; a knocking reduction unit 55 configured to halt or reduce supply of gas fuel to a cylinder in which the knocking is occurring and reduce supply of the gas fuel to other cylinders in which the knocking is not occurring; a first recovery unit 57 configured to recover a state where the gas fuel is halted or reduced in the cylinder in which the knocking is occurring; and a second recovery unit 59 configured to recover a state where the gas fuel is reduced in the other cylinders which are not the cylinder in which the knocking is occurring.

Abstract: A apparatus for an engine, and the apparatus includes an ECU. The ECU is configured to (i) perform a feedback control such that the engine speed converges to a target speed by correcting ignition timing during the feedback control, (ii) make a determination that fuel supplied to the engine is a heavy fuel when an ignition fulfillment rate is equal to or greater than a predetermined threshold value within a predetermined period after the engine is started, the ignition fulfillment rate is a ratio of the advance correction amount of the ignition timing to a maximum ignition correction range, the maximum ignition correction range is a maximum range in which the ignition timing is corrected during the feedback control, and (iii) set the threshold value to a value that depends on a temperature representative value of the engine, the temperature representative value is correlated with the engine temperature.

Abstract: A method for fuel regulation during a non-motoring operating mode of an internal combustion engine is provided. A fuel regulator employs a first fuel to regulate pressure of a second fuel. The first fuel is communicated to the fuel regulator through a first fuel circuit. The method comprises actuating a fuel injector that introduces the first fuel and the second fuel into a combustion chamber of the internal combustion engine during the non-motoring operating mode. The fuel injector is actuated with an injection command signal having a pulse width below a predetermined maximum value whereby no fuel is injected into the combustion chamber and the first fuel drains from the first fuel circuit through the fuel injector to a supply tank.

Abstract: There is disclosed a method of regenerating at least one aftertreatment device in an exhaust system of an internal combustion engine by changing a calibration of the exhaust gas recirculation system with the engine to increase temperature of exhaust gas provided to the at least one aftertreatment device, and further incrementally changing the calibration to obtain an exhaust gas temperature within a target regeneration temperature range.

Abstract: An electronic control unit of the present invention includes: a demand generation level that generates and outputs a demand value concerning various kinds of functions; a physical quantity mediation level that aggregates and mediates the demand value for each predetermined physical quantity; and a controlled variable setting level that sets a controlled variable of the actuator based on the mediated demand value and transmits a signal in a single direction from a higher level to a lower level. A controlled variable mediation level that aggregates and mediates demand values expressed with controlled variables of the actuators set on the controlled variable setting level and a demand value transmitted from the demand generation level not through the physical quantity mediation level, together with demand values mediated by the physical quantity mediation level is provided below the controlled variable setting level.

Abstract: The present application provides a calibration device for calibrating a crank angle of a calibrateable combustion engine, the calibrateable combustion engine and a method for calibrating. The calibration device is provided to determine a trigger wheel angle offset from a combustionless driving of the combustion engine in that an in-cylinder pressure profile is recorded, on the basis of which a trigger wheel angle offset is determined and stored at an offset memory of the combustion engine. The combustion engine is configured to determine a crank angle on the basis of a measured trigger wheel angle and the stored trigger wheel angle offset.

Abstract: A method and apparatus for in situ operating an internal combustion engine comprising determining at least one combustion characteristic for a combustion chamber of the internal combustion engine, comprising an actual heat release signal for the combustion chamber; and inputting the actual heat release signal into a diagnostic logic tree for diagnosing changes in combustion characteristics due to at least one of: a malfunctioning fuel injector, a start of combustion timing error; and a change in fuel quality; and performing a mitigation technique to compensate for the changes in combustion characteristics.

Abstract: A method of monitoring an exhaust gas sensor coupled in an engine exhaust in an engine is provided. The method includes adjusting engine operation responsive to exhaust gas sensor degradation, the degradation identified during deceleration fuel shut-off (DFSO) and compensated based on whether vapor purge operation is occurring in the engine during DFSO.

Abstract: In at least some implementations, an engine control process includes an engine speed test and other steps. The engine speed test includes the steps of a) determining a first engine speed, b) changing the air/fuel ratio of a fuel mixture delivered to the engine, and c) determining a second engine speed after at least some of the air/fuel ratio changing event, Based at least in part on the difference between the first engine speed and the second engine speed it is determined if a change in the air/fuel ratio of the fuel mixture delivered to the engine is needed.

Abstract: A system and method are provided for monitoring a pressure of fuel supplied to the fuel injector, and providing a control input voltage to the piezostack in response to the pressure to cause the injector to provide a fuel injection having a desired shape. In the system and method, providing a control input voltage includes applying a model-based algorithm to the pressure to determine the control input voltage.

Abstract: A technique for fuel system protection for an internal combustion engine comprises determining direct fuel injector temperature as a function of engine operating parameters; and advancing intake valve timing when the temperature rises above a first predetermined value such that the temperature is maintained below a second predetermined value.

Abstract: A method for determining causes of engine stop using ignition power monitoring may include performing ignition power holding determination to determine, in a state in which a vehicle is started and an engine is driven, whether the vehicle is in a key-on state, to which power is consistently applied, in order to hold the starting of the engine of the vehicle. The method also includes performing power-off recognition time comparison by comparing, when ignition power is turned off and the engine is stopped, a time required to recognize ignition power-off in an ECU (Electronic Control Unit) with a preset ignition power-off recognition time for failure determination. The method also performs a power abnormality determination by determining whether the engine is stopped due to ignition power failure when the time required to recognize the ignition power-off in the ECU is not greater than the preset ignition power-off recognition time.

Abstract: A method involves comparing a determined operating parameter of an engine, with a predefined operating parameter. The method further involves controlling a fuel source and an ignition source of the engine so as to operate at least one engine cylinder in a skip fire mode for at least one cycle of a crank shaft when the determined operating parameter is greater than the predefined operating parameter. The controlling involves transitioning the fuel source from a normal mode to the skip fire mode for the at least one cycle of the crank shaft either before transitioning the ignition source from the normal mode to the skip fire mode or when the ignition source is operated in the normal mode.

Abstract: A control device for an internal combustion engine which includes one of the port injection fuel injection valve and the cylinder injection fuel injection valve that serves as a main fuel injection valve, the other of the fuel injection valves that serves as an auxiliary fuel injection valve arranged to be auxiliarily operated in a specified engine driving condition, and which is configured to perform a switching of an injection and a stop of the auxiliary fuel injection valve in accordance with an engine driving condition, the control device includes: the control device being configured to switch the injection and the stop of the auxiliary fuel injection valve in a state where an air-fuel ratio by an injection amount of the fuel by the main fuel injection valve is thicker than a stoichiometric air-fuel ratio.

Abstract: An engine structure for a multi-cylinder, opposed-piston engine includes a cylinder block with a plurality of inline cylinders. Each cylinder has ends with an outside diameter and an intermediate portion between the ends of a relatively larger outside diameter than the ends. The cylinder block includes a bearing web structure that positions bearing web elements outside of a plane that longitudinally bisects all of the cylinders. The cylinder block is split into two sections so as to permit cylinder liners to be inserted into and removed from cylinder tunnels in the cylinder block.

Abstract: A reciprocating engine includes a cylinder head, a cylinder liner, an outer seal, and an inner seal. The cylinder liner has a flange proximate to the cylinder head, where the cylinder liner extends circumferentially around a combustion chamber, and the cylinder head defines an end of the combustion chamber. The outer seal is disposed between the flange of the cylinder liner and the cylinder head, where the outer seal is configured to transfer an axial compressive load between the cylinder head and the cylinder liner. The inner seal is disposed between the cylinder liner and the cylinder head proximate to the combustion chamber. The inner seal is configured to isolate an inner face of the outer seal from the combustion chamber. A first compressive strength of the outer seal is greater than a second compressive strength of the inner seal.

Abstract: The present disclosure provides a nozzle for an aircraft turboprop engine with an unducted fan, including: an inner wall, an outer wall radially spaced apart from the inner wall and concentric with the inner wall, a junction area of the inner and outer walls including an opening contained in a plane transverse to a longitudinal axis of the nozzle. In particular, the junction area of the inner and outer walls includes two connecting plates and a member to secure the two connecting plates together, or in another form, the junction area includes a pad secured to the inner wall, and a pad secured to the outer wall, facing the pad of the inner wall of the nozzle.

Abstract: An ejector/mixer for a gas turbine engine includes an annular wall having upstream end adapted to be fastened to an engine case and a downstream end forming a plurality of lobes. A support member interconnects the lobes, and includes an annular blade located radially inwardly of the bight of the lobes. The lobes extend radially inwardly downstream relative to the annular wall and the support member includes an annular blade and has spaced apart joint surfaces spaced apart to coincide with the joint surfaces of a respective lobes. The spaced-apart joint surfaces of the support member being profiled to mate with the corresponding joint surface of the lobes.

Abstract: An ejector comprises a primary nozzle having an annular wall forming part of an outer boundary of an exhaust portion of a primary flow path of a gas turbine engine. The annular wall has a downstream end defining a plurality of circumferentially distributed lobes. The ejector further comprises a secondary nozzle having an annular wall disposed about the primary nozzle, the primary nozzle and the secondary nozzle defining a secondary flow passage therebetween for channeling a secondary flow. The secondary nozzle defines a mixing zone downstream of an exit of the primary nozzle. A flow guide ring is mounted to the primary nozzle lobes. The ring has an aerodynamic surface extending from a leading edge to a trailing edge respectively disposed upstream and downstream of the exit of the primary nozzle. The aerodynamic surface of the ring is oriented to guide the high velocity primary flow into the mixing zone.

Abstract: Thrust reverser actuator systems are disclosed herein. An example apparatus disclosed herein includes a first controller to communicate with a first flight computer and a second flight computer of an aircraft. The example apparatus also includes a second controller to communicate with the first flight computer and the second flight computer. The example apparatus further includes a thrust reverser and a first electrical actuator coupled to the thrust reverser. The first electrical actuator is to be communicatively coupled to the first controller and the second controller. The example apparatus also includes a second electrical actuator coupled to the thrust reverser. The second electrical actuator is to be communicatively coupled to the second controller. The first electrical actuator and the second electrical actuator are to synchronously actuate the thrust reverser.

Abstract: A hybrid rocket engine is described that achieves stable, highly efficient hybrid combustion by having a core flow of fuel-rich gas generator gases, with the flow being surrounded with an annular injection of oxidizer. The fuel-rich gas serves to vaporize and decompose the oxidizer, such as nitrous oxide, and prepare it for effective, stable combustion. In one embodiment, this is done at the head-end of a combustion chamber. The combustion products can then be expanded through a nozzle to create thrust. The engine can be an upper stage engine that can include modular thrust chambers and an integrated aerospike nozzle. The thrust chambers can be arranged in an array that rings the top of the aerospike nozzle.

Abstract: Various methods and systems are provided for cooling gas admission valves configured to admit gaseous fuel to an engine. In one embodiment, a system comprises an intake manifold including a gaseous fuel line for supplying gaseous fuel to a plurality of cylinders of an engine configured to combust the gaseous fuel, and at least one gas admission valve mounted to the gaseous fuel passage for regulating admission of the gaseous fuel to the plurality of cylinders. The system further includes a thermal management system configured to direct thermal fluid to the plurality of gas admission valves.

Abstract: Methods and systems are provided for operating an engine with variable displacement engine (VDE) operation coupled to a twin scroll turbocharger. One method comprises directing exhaust from a first outer cylinder and a first inner cylinder of four cylinders to a first scroll of the twin scroll turbocharger, directing exhaust from a second outer cylinder and a second inner cylinder of the four cylinders to a second scroll of the twin scroll turbocharger, and during a first condition, firing all four cylinders with uneven firing.

Abstract: This multi-cylinder internal combustion engine (1) is provided with an EGR device (30) containing an EGR cooler (27), a valve overlap period in which valve opening periods of intake valves (20) and exhaust valves (21) overlap one another is set, and the multi-cylinder internal combustion engine (1) has four cylinders (2). The multi-cylinder internal combustion engine (1) comprises: four exhaust side branch conduits (15), one provided for each of the cylinders (2); a storage tank (31) configured to store condensed water (CW) generated by the EGR cooler (27); and four condensed water introduction conduits (33), one provided for each of the exhaust side branch conduits (15) and communicating the exhaust side branch conduit (15) with the storage tank (31).

Abstract: One variation may include an assembly comprising a housing assembly having an exhaust flow port and an EGR flow port formed therein, an exhaust flow port valve plate received in the housing assembly constructed and arranged to move to a position to at least partially block flow of gas through the exhaust flow port, and an EGR port valve plate received in the housing assembly and constructed and arranged to move to a position to at least partially block gas through the EGR flow port, and a single actuator connected to move both of the exhaust flow port valve plate and the EGR flow port valve plate. Another variation may include a combined low pressure exhaust gas recirculation valve and exhaust throttle valve including first and second valve plates connected to a common valve shaft in spaced apart relationship.

Abstract: A method, comprising: adjusting an evaporative emissions leak test parameter based on a ratio of cylinder run time of a deactivatable cylinder of an engine, to vehicle run time; and indicating degradation based on the adjusted parameter. The adjusted parameter may thus more accurately reflect the state of a vehicle configured to run with one or more cylinders deactivated. In this way, the evaporative emissions leak test may realize improved robustness and performance metrics, thus reducing warranty costs associated with poor test metrics.

Abstract: Atomic oxygen is provided for the purpose of promoting reliable ignition and smooth combustion in a spark ignition internal combustion engine is to disperse a low concentration of an atomic oxygen precursor, such as nitrous oxide (N2O), into the flammable mixture of air and gasoline vapor prior to the time of ignition. The introduction of N2O may take place in the intake manifold, in the stream of exhaust gas being returned as part of the EGR process, or directly into the combustion chamber (for example through a small orifice in the base of the spark plug or through a small nozzle located elsewhere in the cylinder head). Introduction of N2O directly into the combustion chamber may be continuous, or it may be pulsed so as to occur at the time of or shortly before, spark ignition.

Abstract: A diesel particulate filter includes a carrier in which facing sides of a plurality of filter walls are spaced apart from each other form an exhaust gas inlet channel and an exhaust gas outlet channel, and a plurality of plugs are disposed to block a back end of the exhaust gas inlet channel and a front end of the exhaust gas outlet channel. A porosity or a pore size of the filter walls in a front part of the carrier is different from a porosity or a pore size of the filter walls in a back part of the carrier. The front part and the back part of the carrier are divided based on a longitudinal direction of the exhaust gas inlet channel, to prevent soot trapped in the carrier from being concentrated in a back-end part of the diesel particulate filter.

Abstract: An insert type expansion pipe-integrated air cleaner may include an air cleaner body having a filter chamber in which air is introduced from an outside, the filter chamber having a chamber space provided with a filter, the chamber space being covered by an air cleaner cover, an expansion pipe chamber connected to the filter chamber such that the introduced air is discharged from the expansion pipe chamber to the outside, and a female passage boss through which the introduced air passes from the filter chamber to the expansion pipe chamber by having a cross-sectional area smaller than a cross-sectional area of the expansion pipe chamber while the female passage boss divides the filter chamber and the expansion pipe chamber.

Abstract: The disclosed apparatus, systems and methods relate to an intake manifold for use in internal combustion engines which pairs cylinders together so as to allow the sharing of air and fuel to improve efficiency and power.

Abstract: A jet propelled watercraft includes a watercraft body, an engine mounted on the watercraft body, an air intake box configured to supply air to the engine, and a mounting portion provided on the air intake box. The air intake box is disposed opposite to the engine. An electrical device is mounted on a front surface and a right surface of the air intake box, which are different from the surfaces of the air intake box that oppose the engine. The electrical device is removably mounted on the mounting portions without using an implement such as a tool.

Abstract: A mechanical fuel pump is disclosed for delivering fuel to an engine of a vehicle, the mechanical fuel pump having an activated configuration and a deactivated configuration. A dual fuel system and method are also disclosed for use with the mechanical fuel pump.

Abstract: A high-pressure pump, in particular a plug-in pump, for a fuel system of an internal combustion engine includes a housing, and a flange that is rigidly arranged on the housing. The flange is formed from at least two parts. The pump defines a groove-shaped receiving area, and a radially inward region of the flange part is received in the receiving area. The at least two parts of the flange are held on the housing via at least one of a caulked joint and a press connection.

Abstract: Systems and methods for starting an engine of a hybrid vehicle that includes two electric machines capable of starting an engine are presented. In one example, one of the two electric machines is selected to start the engine in response to degradation of one or more vehicle components and an engine start request.

Abstract: A vehicular power transmission including a crank type continuously variable transmission is provided in which when the rotational speed of an engine during deceleration fuel cut-off is at least a first rotational speed, which is an upper limit of rotational speed at which plunging of a starter motor is possible, but less than a second rotational speed, which is a lower limit of rotational speed at which self-ignition of the engine is possible. The engine is cranked and restarted by transmitting the driving force of an electric motor of a shift actuator to an input shaft via first and second engagement portions. This eliminates the need for restarting the engine with the starter motor by waiting until the rotational speed of the engine has become less than the first rotational speed, thus reducing the time required for restarting the engine. Moreover, the electric motor can be made small.

Abstract: An auxiliary heating system comprising interconnected piping which forms a closed fluid flow circuit for permitting a passage of coolant therein, and having formed chamber openings along a length thereof to receive at least one heating element which projects into the closed fluid flow circuit to be in direct contact with, and heat, the coolant. A pump is provided for circulating the coolant, along with a flow switch for monitoring flow of the coolant through the closed fluid flow circuit, wherein if the flow has ceased through the closed fluid flow circuit, the flow switch instructs the system to deactivate the heating elements.

Abstract: Aspects of the invention include a semiconductor device that includes a voltage-controlled type semiconductor element connected to a primary side of an ignition coil for supplying a voltage to an ignition device of an internal combustion engine, a first resistor and a second resistor inserted in series in a supplying path of an input signal for controlling a gate of the voltage-controlled type semiconductor element and a current control circuit including a current limiting circuit for controlling current flowing through the voltage-controlled type semiconductor element. Aspects of the invention also include a first by-pass forming element that is connected in parallel to the second resistor and by-passes the second resistor in a turning ON process of the voltage-controlled type semiconductor element, and a second by-pass forming element that is connected in parallel to the first resistor and the second resistor.

Abstract: A fuel property determination apparatus for an internal combustion engine is applied to an internal combustion engine that is equipped with an ignition plug and an ignition timing controller. An electronic control unit provided in the fuel property determination apparatus executes a determination process of making a determination on a property of a fuel supplied to the internal combustion engine based on an ignition sufficiency ratio, during a predetermined period after startup of the internal combustion engine. The electronic control unit is configured to determine that the property of the fuel is heavy when a determination index value that is obtained by subjecting the ignition sufficiency ratio to a smoothing process is equal to or larger than a predetermined threshold. The electronic control unit is configured to set a smoothing coefficient to a value corresponding to each of a first period, a second period, and a third period.

Abstract: A control device suitable for use in a vehicle includes a housing, a circuit board having a circuit element disposed thereat, and a thermal fuse having a first contact soldered at the circuit board at a first solder joint and a second contact soldered at the circuit board at a second solder joint. The thermal fuse is biased by the housing of the control device to exert a force at the circuit board in a direction away from a surface of the circuit board. When a temperature at the circuit element exceeds a threshold temperature and when the first solder joint at the first contact sufficiently melts, the thermal fuse moves the first contact away from the circuit board to break the electrical connection at the first solder joint and between circuitry electrically connected to the first contact and circuitry electrically connected to the second contact.

Abstract: A wave power electricity generation device includes a base unit, an electricity generation unit mounted on the base unit, a driving unit and a pneumatic unit. The driving unit is pivoted to the base unit, and includes a floating frame and a swing arm that is pivoted to the base unit and that interconnects the electricity generation unit and the floating frame. The driving unit is adapted to be driven by waves to drive operation of the electricity generation unit and to actuate operation of the pneumatic unit for compressing air into high pressure air that is to be stored in the floating frame. The high pressure air is released to actuate the electricity generation unit when the electricity generation unit is unable to be driven due to insufficient waves.

Abstract: Three bodies interact to drive a transmission having a pair of one-way clutches coupling a single length of drive chain or other elongate flexible member to an intermeshed pair of counter rotatable gears so as to drive a primary shaft in a single rotational direction. The three bodies are a fixed body, a floating body, and a suspended and usually submerged weighted body. The three bodies are interconnected by the single length of the elongate flexible member and are spaced apart there along. The weighted body is mounted at one end of the elongate flexible member. The primary shaft is mounted above the surface of a moving fluid mass to either the fixed or floating body. The end of the flexible member opposite to the weight is mounted to the other of the fixed or floating body.

Abstract: An accelerator and water turbine assembly is provided for mounting in a tidal stream having a water turbine (12) and a water flow accelerator for providing a turbine driver current having a speed greater than that of the uninterrupted ambient tidal stream in which the accelerator has an accelerator body member (11) having a water flow facing front face (13) and side faces (14) depending therefrom around which the water flows adjacent each of the side faces as a turbine driver current and in which the water turbine (12) is mounted to be at least partially shrouded by the accelerator body member from the accelerated turbine driver current flowing adjacent and relatively close to a side face of the accelerator where the water flow achieves substantially maximum velocity and in which the accelerator is laterally spaced apart from the turbine driver current modifying effect of any other flow obstruction.