Active drag-reduction system and a method of reducing drag experienced by a vehicle

Abstract

An active drag-reduction system has first 22 and second 24 fluid outlets located on a vehicle 10 adjacent to a low pressure (drag) region 12, wherein fluid ejected from the second fluid outlet 24 is at a higher pressure/ejection velocity than from the first fluid outlet 22. Turbulent and/or low pressure regions adjacent to vehicles are not uniform, but rather have a varying intensity. For instance, the centre of a region may have a lower pressure and/or more turbulent nature than the periphery of the region. The system injects relatively higher pressure air or relatively higher speed air into the relatively lower pressure/more turbulent part of the low pressure/turbulent region, and relatively lower pressure air or relatively lower speed air into the relatively higher pressure/less turbulent part of the low pressure/turbulent region, compared to each other.

1 . An active drag-reduction system for a vehicle in which at least one turbulent and/or low-pressure region is formed adjacent to the vehicle when moving at a speed above a predetermined threshold speed, the active drag-reduction system configured to reduce the at least one turbulent and/or low-pressure region when activated, the active drag-reduction system comprising:
 at least one propelling nozzle located adjacent to the at least one region and arranged to eject fluid substantially toward an interior of the at least one region; and   a device for providing gas to the at least one nozzle for expulsion into the at least one region;   wherein the at least one propelling nozzle comprises a tip ring supersonic nozzle and/or elliptic sharp tipped shallow lobed nozzle.   
     
     
         2 . A vehicle configured such that, when moving at a speed above a predetermined threshold speed, at least one turbulent and/or low-pressure region is formed adjacent to the vehicle, the vehicle comprising an engine system comprising:
 an internal combustion engine having an intake and an exhaust;   a turbine connected to the exhaust such that the turbine rotates in response to receiving exhaust gases from the engine;   an alternator connected to the turbine such that the alternator generates electrical power in response to rotation of the turbine; and   an exhaust outlet connected to the turbine, for removing exhaust gases that have been used to rotate the turbine, the exhaust outlet comprising a propelling nozzle located on a rear of the vehicle such that the exhaust gases are expelled substantially toward an interior of a turbulent and/or low-pressure region behind the vehicle;   wherein the exhaust provides gas directly to the nozzle.   
     
     
         3 . A method of reducing vehicular drag, the method comprising the steps of:
 providing a vehicle according to  claim 2 ; and   expelling gas from the at least one nozzle substantially toward an interior of the at least one region.   
     
     
         4 . An engine system of a vehicle, the engine system comprising:
 an internal combustion engine having an intake and an exhaust;   a Pelton wheel turbine of the impulse type connected to the exhaust such that the turbine rotates in response to receiving exhaust gases from the engine;   an exhaust outlet to which exhaust gases are delivered after passing through the turbine;   an alternator connected to the turbine such that the alternator generates electrical power in response to rotation of the turbine;   a propelling nozzle distinct from the exhaust outlet, the propelling nozzle arranged to eject fluid substantially toward an interior of a turbulent and/or low-pressure region behind the vehicle;   an air pump connected to the turbine, the air pump configured to take in ambient air at a pump inlet and expel pressurised air to the propelling nozzle; and   the propelling nozzle configured such that gasses from the propelling nozzle are converted into a higher speed propelling jet, relative to the speed of the expelled pressurised air from the air pump.   
     
     
         5 . The engine system of  claim 4 , wherein the air pump is a reciprocating piston compressor. 
     
     
         6 . The engine system of  claim 4 , wherein the alternator is spaced from the engine by more than 25 cm. 
     
     
         7 . The engine system of  claim 4 , further comprising:
 a compressor connected to the turbine such that the compressor rotates in response to rotation of the turbine, wherein the compressor is arranged to compress gas for delivery to the intake; and   a metering valve, provided between the compressor and the intake, configured to regulate the gas pressure provided to the intake.   
     
     
         8 . A method of using energy in exhaust gas from an internal combustion engine, the method comprising the steps of:
 providing an internal combustion engine of a vehicle having an intake and an exhaust;   providing a Pelton wheel turbine of the impulse type connected to the exhaust;   rotating the turbine in response to receiving exhaust gases from the engine;   delivering the exhaust gases to an exhaust outlet after passing through the turbine;   providing an alternator connected to the turbine;   generating electrical power with the alternator in response to rotation of the turbine;   providing an air pump connected to the turbine;   taking in ambient air at a pump inlet of the air pump;   providing a propelling nozzle distinct from the exhaust outlet, the propelling nozzle arranged to eject fluid substantially toward an interior of a turbulent and/or low-pressure region behind the vehicle; and   expelling pressurised air from the air pump to the propelling nozzle; and   converting the expelled pressurised air from the air pump with the propelling nozzle into a higher speed propelling jet, relative to the speed of the expelled pressurised air from the air pump.   
     
     
         9 . A vehicle configured such that, when moving at a speed above a predetermined threshold speed, at least one high pressure region is formed adjacent to the vehicle, the vehicle comprising:
 at least one propelling nozzle located adjacent to the at least one region; and   a system for providing gas to the at least one nozzle for expulsion into the at least one region.   
     
     
         10 . The vehicle of  claim 9 , wherein the gas is provided at a relatively high temperature. 
     
     
         11 . A method of reducing vehicular drag, the method comprising the steps of:
 providing a vehicle according to  claim 9 ; and   expelling gas from the at least one nozzle into the at least one region.