Internal combustion engine with fan system

Abstract

In an internal combustion engine cooling system, wherein a fan with an adjustable cooling performance is provided with a fan wheel having a hub with radial fan blades pivotally supported on the hub, a control piston is disposed in the hub and connected to the blades for the pivot position adjustment thereof over a range from a suction position to a blowing position including a neutral position in which the blades are oriented in a plane including the axis of rotation of the fan wheel under the control of a control unit causing movement of the piston for pivoting the blades to a position for a cooling performance adjusted to the engine requirements. The system is simple, safe and efficient and permits counter flow operation of the fan for cleaning purposes.

1 . An internal combustion engine with a fan system including a fan wheel ( 1 ) having an adjustable cooling performance and an engine control unit ( 50 ) providing control data for the cooling performance of the fan needed for cooling the internal combustion engine ( 18 ) or a cooling circuit comprising the internal combustion engine ( 18 ),
 said fan wheel ( 1 ) including a fan wheel hub ( 4 ) with radial fan blades ( 2 ) pivotally supported on the hub ( 4 ) and including a control piston ( 11 ) axially movably disposed in the hub ( 4 ) and connected to the fan blades ( 2 ) for pivoting the fan blades ( 2 ),   the fan blades ( 2 ) being pivotable over a range including a switch-over neutral position in which the blades ( 2 ) are oriented in a plane including the axis of rotation of the fan wheel ( 1 ), so that the fan wheel ( 1 ) is adjustable to blow in either axial direction depending on the pivot position of the blades at one or the other side of the switchover neutral position,   a measuring arrangement ( 26 ) for determining the position of the control piston ( 11 ) in the hub ( 4 ) and, as a result, the pivot positions of the blades ( 2 ),   a fan control unit ( 51 ) in communication with the measuring arrangement for recording the actual pivot position of the fan blades ( 2 ) and comparing it with a desired blade position which is determined based on engine operating conditions for providing a desired cooling performance with a certain blade angle position, the fan control unit ( 51 ) providing, upon detecting a deviation between the actual and the desired pivot position of the fan blades ( 2 ), an input signal for adjusting the fan blade pivot position.   
     
     
         2 . The internal combustion engine according to  claim 1 , wherein control valves ( 54 ,  55 ) are provided for controlling the admission of fluid to the piston ( 11 ) in the hub ( 4 ) and for the release of the fluid for adjusting the pivot position of the fan blades ( 2 ), the control signal for adjusting the blade pivot position being supplied to the respective control valve ( 54 ,  55 ). 
     
     
         3 . The internal combustion engine according to  claim 1 , wherein the measuring arrangement includes a Hall sensor arrangement ( 36 ) with a magnet ( 37 ) disposed on the control piston ( 11 ) so as to be movable with said control piston ( 11 ) and said fan wheel hub ( 4 ) and a position sensor ( 35 ) stationarily supported adjacent the fan wheel hub ( 4 ) for sensing the speed of the fan wheel ( 1 ) and the position of the piston ( 11 ). 
     
     
         4 . The internal combustion engine according to  claim 1 , wherein the desired cooling performance of the fan wheel ( 1 ) is determined based on the engine speed and various engine operating conditions. 
     
     
         5 . The internal combustion engine according to  claim 2 , wherein the desired cooling performance is provided as an input signal with a signal strength weighted over the performance spectrum and established in relation to the blade pivot position in one of a computerized, graphic and performance graph-based manner such that a minimum signal strength of the input signal corresponds to a maximum blade angle position for maximum cooling performance whereby, upon signal failure, the fan blades are in a maximum cooling performance position. 
     
     
         6 . The internal combustion engine according to  claim 1 , wherein the input signal is a PWM (Pulse Width Modulated) signal which is in a relationship with the blade angle position in such a way that a low PWM value of 0% corresponds to one blade pivot angle end position and a high value of 100% of the PWM signal corresponds to the opposite blade pivot angle end position, the blades ( 2 ), upon pivoting from one to the other end position, and vice versa, moving through their neutral position. 
     
     
         7 . The internal combustion engine according to  claim 6 , wherein the one or the other blade pivot angle end position corresponds to the end position of the control piston ( 11 ) which it assumes when no pressurized fluid is applied thereto while the respective other or one blade pivot angle end position corresponds to the end position of the control piston ( 11 ) when subjected to full pressure. 
     
     
         8 . The internal combustion engine according to  claim 1 , wherein the respective blade angle is formed by the angle of the blade ( 2 ) established between a plane normal to the axis of rotation of the fan wheel ( 1 ) and the angle of the blades ( 2 ) relative thereto. 
     
     
         9 . The internal combustion engine according to  claim 3 , wherein the Hall sensor arrangement is provided so as to sense the position of the control piston ( 11 ) and the speed of the fan wheel ( 1 ). 
     
     
         10 . The internal combustion engine according to  claim 2 , wherein the control valves ( 54 ,  55 ) are 3/2-way inlet and outlet valves. 
     
     
         11 . The internal combustion engine according to  claim 9 , wherein the Hall sensor arrangement ( 36 ) includes a speed transmitter for the fan wheel ( 1 ). 
     
     
         12 . The internal combustion engine according to  claim 11 , wherein the speed of the fan wheel ( 1 ) assigned to the respective desired cooling performance is monitored via the Hall sensor arrangement ( 36 ) acting as speed signal transmitter. 
     
     
         13 . A cooling system for an internal combustion engine with a fan system including a fan wheel ( 1 ) having an adjustable cooling performance and an engine control unit ( 50 ) providing control data for the cooling performance of the fan needed for cooling the internal combustion engine ( 18 ) or a cooling circuit comprising the internal combustion engine ( 18 ),
 said fan wheel ( 1 ) including a fan wheel hub ( 4 ) with radial fan blades ( 2 ) pivotally supported on the hub ( 4 ) and including a control piston ( 11 ) axially movably disposed in the hub ( 4 ) and connected to the fan blades ( 2 ) for pivoting the fan blades ( 2 ),   the fan blades ( 2 ) being pivotable between opposite end positions over a range including a neutral switch-over position in which the blades ( 2 ) are oriented in a plane including the axis of rotation of the fan wheel ( 1 ) so that the fan wheel ( 1 ) is adjustable to blow in either axial direction depending on the pivot position of the blades ( 2 ) at one or the other side of the neutral switch-over position,   a measuring arrangement ( 26 ) for determining the position of the control piston ( 11 ) in the hub ( 4 ) and, as a result, the pivot positions of the blades ( 2 ),   a fan control unit ( 51 ) in communication with the measuring arrangement for recording the actual pivot position of the fan blades ( 2 ) and comparing it with a desired blade position which is determined based on engine operating conditions for providing a desired cooling performance with a certain blade angle position, the fan control unit ( 51 ) providing, upon detecting a deviation between the actual and the desired pivot position of the fan blades ( 2 ), an input signal for adjusting the fan blade pivot position   said fan wheel ( 1 ) having a cooling performance which is variable and adjustable dependent on the respective speed and the operating conditions of the internal combustion engine under the control of a control signal determined on the basis of the desired cooling performance.   
     
     
         14 . The cooling system according to  claim 13 , wherein the adjustment of the fan wheel ( 1 ) to the desired cooling performance occurs based on a previous setting in a control circuit in which the respective blade angle is compared to the desired blade angle and deviations are corrected by controlling the inlet and outlet valves ( 54 ,  55 ) wherein an examination of the correction of the setting of the blade angle to the desired blade angle is used as a functional examination of the inlet and outlet valves ( 54 ,  55 ). 
     
     
         15 . The cooling system according to  claim 14 , wherein the control circuit ends in an actual position—desired position comparison for the blade angle wherein, with values deviating from the desired blade angle, a new pass through the control circuit is initiated and wherein for the comparison an overall time limit is predetermined, which, when exceeded, results in a system error indication. 
     
     
         16 . The cooling system according to  claim 15 , wherein, in accordance with the predetermined overall time for the passage of the control circuit and the—within the given overall time—relatively small displacement travel of the control piston ( 11 ), a fixed response time is provided for the inlet and outlet valves ( 54 ,  55 ) which is a fraction of the overall time. 
     
     
         17 . The cooling system according to  claim 13 , wherein the control circuit ( 51 ) is part of a control arrangement ( 50 ) for which, at an input, a signal value for the desired cooling performance or, respectively, the desired blade position, in particular a PWM signal value, is determined and a transition to the control circuit within a given overall time occurs only if the signal exceeds a predetermined minimum value.