Pump units

Abstract

A pump unit includes a pump, a motor configured to drive the pump, a control device communicating with the motor and a pressure detection device configured to detect a pressure of a fluid discharged from the pump. The control device is configured to control the motor, so that a pressure detected by the pressure detection device becomes relatively equal to a target pressure. The control device is further configured to determine an estimated pressure of the fluid discharged from the pump. The control device determines whether or not an abnormality occurs based at least one of the following: a detected pressure, a difference between the target pressure and the detected pressure and/or a difference between the detected pressure and the estimated pressure.

1 . A pump unit comprising:
 a pump;   a sensor-less brushless motor configured to drive the pump;   a control device communicating with the brushless motor; and   a pressure detection device disposed on a discharge side of the pump,   wherein the control device is configured to control the brushless motor, so that a pressure detected by the pressure detection device becomes relatively equal to a target pressure; and   wherein the control device is further configured to be able to determine a value of current supplied to the brushless motor and a rotational speed of the brushless motor,   such that when an abnormality occurs in the pressure detection device, the control device determines an estimated pressure on the discharge side of the pump based on the determined current value and the determined rotational speed and controls the brushless motor so that the determined estimated pressure becomes relatively equal to the target pressure.   
     
     
         2 . A pump unit comprising:
 a pump;   a sensor-less brushless motor configured to drive the pump;   a control device communicating with the brushless motor;   a pressure detection device disposed on a discharge side of the pump;   wherein the control device is configured to control the brushless motor, so that a pressure detected by the pressure detection device becomes relatively equal to a target pressure; and   wherein the control device is further configured to be able to determine a value of current supplied to the brushless motor and a rotational speed of the brushless motor,   wherein the control device determines an estimated pressure on the discharge side of the pump based on the determined current value and the determined rotational speed; and   wherein the control device determines whether or not an abnormality occurs to the pressure detection device based on the detected pressure and the estimated pressure.   
     
     
         3 . The pump unit as in  claim 2 , wherein the control device determines whether or not an abnormality occurs based on a difference between the target pressure and the detected pressure and a difference between the detected pressure and the estimated pressure. 
     
     
         4 . The pump unit as in  claim 3 , wherein the control device determines that an abnormality occurs if the difference between the target pressure and the detected pressure is equal to or greater than a first pressure difference and the difference between the detected pressure and the estimated pressure is equal to or greater than a second pressure difference. 
     
     
         5 . The pump unit as in  claim 3 , wherein the control device determines that an abnormality has occurred if the difference between the target pressure and the detected pressure has exceeded a first pressure difference and the difference between the detected pressure and the estimated pressure has exceeded a second pressure difference for a predetermined time period. 
     
     
         6 . A pump unit comprising:
 a pump;   a motor configured to drive the pump;   a control device communicating with the motor; and   a pressure detection device configured to detect a pressure of a fluid discharged from the pump;   wherein the control device is configured to control the motor, so that a pressure detected by the pressure detection device becomes relatively equal to a target pressure; and   wherein the control device is further configured to determine an estimated pressure of the fluid discharged from the pump;   wherein the control device determines whether or not an abnormality occurs based at least one of the following: a detected pressure, a difference between the target pressure and the detected pressure, and a difference between the detected pressure and the estimated pressure.   
     
     
         7 . The pump unit as in  claim 6 , wherein the control device determines that an abnormality occurs if the detected pressure is greater than an upper threshold value. 
     
     
         8 . The pump unit as in  claim 7 , wherein the control device determines that an abnormality has occurred if the detected pressure has exceeded the upper threshold value for a first predetermined time period. 
     
     
         9 . The pump unit as in  claim 6 , wherein the control device determines that an abnormality occurs if the detected pressure is lower than a lower threshold value. 
     
     
         10 . The pump unit as in  claim 9 , wherein the control device determines that an abnormality has occurred if the detected pressure has not exceeded the lower threshold value for a second predetermined time period. 
     
     
         11 . The pump unit as in  claim 6 , wherein the control device determines that an abnormality occurs if the difference between the target pressure and the detected pressure is equal to or greater than a first pressure difference. 
     
     
         12 . The pump unit as in  claim 6 , wherein the control device determines that an abnormality occurs if the difference between the detected pressure and the estimated pressure is equal to or greater than a second pressure difference. 
     
     
         13 . The pump unit as in  claim 6  wherein the control device determines that an abnormality has occurred if the difference between the target pressure and the detected pressure has exceeded a first pressure difference and the difference between the detected pressure and the estimated pressure has exceeded a second pressure difference for a predetermined time period. 
     
     
         14 . The pump unit as in  claim 6  wherein the control device determines that an abnormality has occurred if a relatively maximum current has been supplied to the motor for a predetermined time period. 
     
     
         15 . The pump unit as in  claim 6  wherein the motor is a sensorless, brushless motor and the control device is configured to be able to determine a value of current supplied to the motor and a rotational speed of the motor; and the control device can further determine the estimated pressure based on the current value and the rotational speed. 
     
     
         16 . The pump unit as in  claim 6 , wherein the pump is a fuel pump.