Pressure-supply device for an electrohydraulic valve control of gas-exchange valves in internal combustion engines

Abstract

A pressure-supply device for an electrohydraulic valve control of gas-exchange valves in internal combustion engines which has a fluid reservoir, a fluid output for the connection of the valve control, and a high-pressure pump which removes fluid from the fluid reservoir and delivers it under high pressure to the fluid output. To attain high pump efficiency and high system dynamics, the high-pressure pump is constructed as constant-displacement pump having a pump inlet and a pump outlet, and the pump outlet is connectible by a switchover valve alternately to the fluid output and, accompanied by blocking of the fluid output, to the fluid reservoir.

1 - 14 . (canceled)  
     
     
         15 . A pressure-supply device for an electrohydraulic valve control of a gas-exchange valve in an internal combustion engine, comprising: 
 a fluid reservoir,    a fluid output under high pressure for connection of a distributor line of the valve control;    a switchover valve; and    a high-pressure pump configured to deliver fluid from the fluid reservoir and to charge the fluid to high pressure,    wherein the high-pressure pump is a constant-displacement pump having a pump inlet and a pump outlet, the pump outlet being connectible alternately by the switchover valve to the fluid output, and being connectible to the fluid reservoir accompanied by a blocking of the fluid output.    
     
     
         16 . The pressure-supply device as recited in  claim 15 , wherein the constant-displacement pump is self-priming, and the pump inlet is connected to the fluid reservoir.  
     
     
         17 . The pressure-supply device as recited in  claim 15 , a presupply pump configured to draw in fluid from the fluid reservoir connected to the pump inlet of the constant-displacement pump.  
     
     
         18 . The pressure-supply device as recited in  claim 15 , wherein the switchover valve includes a 2/2-way valve positioned in a bypass connecting the pump outlet to the fluid reservoir, and a non-return valve that is connected on one hand to the pump outlet and on the other hand to the fluid output and has a blocking direction pointing toward the pump outlet.  
     
     
         19 . The pressure-supply device as recited in  claim 18 , wherein the 2/2-way valve is a solenoid valve having spring resetting.  
     
     
         20 . The pressure-supply device as recited in  claim 15 , wherein the switchover valve is constructed as a 3/2-way valve having two valve outputs and one valve input switchable alternately to the valve outputs; and the valve input is connected to the pump outlet of the constant-displacement pump, one of the valve outputs being connected to the fluid output and the other of the valve outputs is connected to the fluid reservoir.  
     
     
         21 . The pressure-supply device as recited in  claim 20 , wherein the 3/2-way valve is a solenoid valve having spring resetting.  
     
     
         22 . The pressure-supply device as recited in  claim 19 , further comprising: 
 an electronic control unit that is connected to a sensor detecting the pressure at the fluid output, and that switches the solenoid valve depending upon a drop below or an exceeding of a pressure threshold, the solenoid valve being linked to the electronic control unit.    
     
     
         23 . The pressure-supply device as recited in  claim 15 , wherein the fluid output is connected via a pressure-limiting valve to a return line running to the fluid reservoir.  
     
     
         24 . he pressure-supply device as recited in  claim 23 , wherein the connection of the switchover valve to the fluid reservoir is produced on an output side of the pressure-limiting valve connected to the return line  
     
     
         25 . The pressure-supply device as recited in  claim 23 , further comprising: 
 a restrictor arranged in the return line.    
     
     
         26 . The pressure-supply device as recited in  claim 23 , further comprising: 
 a pressure-limiting valve arranged in the return line.    
     
     
         27 . The pressure-supply device as recited in  claim 23 , further comprising: 
 a non-return valve having a defined opening pressure, the non-return valve being arranged in the return line.    
     
     
         28 . The pressure-supply device as recited in  claim 15 , further comprising: 
 a high-pressure accumulator connected to the fluid output.