Abnormality Diagnostic Device and Abnormality Diagnostic Method for Booster
An abnormality diagnostic device and an abnormality diagnostic method for a booster according to the present invention: determine that a negative pressure sensor operates normally, when an output of the negative pressure sensor changes in response to a decrease in intake pressure; determine that a negative pressure pump operates normally, when the pressure in a negative pressure chamber is decreased by operating the negative pressure pump, and the pressure decrease is determined by the negative pressure sensor determined to be normal; determine that the negative pressure pump is abnormal when the pressure decrease is not determined by the negative pressure sensor; and determine that a negative pressure leakage has occurred, when the pressure in the negative pressure chamber, which has been decreased by the negative pressure pump, is not maintained.
1 . An abnormality diagnostic device for a booster including: a negative pressure pump that generates a negative pressure; a negative pressure chamber into which the negative pressure generated by the negative pressure pump and an intake pipe negative pressure of an internal combustion engine are introduced; and a pressure sensor that measures a pressure in the negative pressure chamber, the booster boosting a brake operating force by a negative pressure in the negative pressure chamber,
the abnormality diagnostic device comprising:
a first determining unit configured to determine a change in a measured pressure value obtained by the pressure sensor, in a state in which the negative pressure pump is stopped;
a second determining unit configured to determine a change in a measured pressure value obtained by the pressure sensor, in a state in which the negative pressure pump is operated; and
a diagnosing unit configured to receive a determination result of the first determining unit and a determination result of the second determining unit, to generate abnormality diagnostic information for each of the negative pressure pump and the pressure sensor.
2 . The abnormality diagnostic device for the booster, according to claim 1 ,
wherein the first determining unit is configured to determine the change in the measured pressure value obtained by the pressure sensor, in the state in which the negative pressure pump is stopped and in a condition in which the pressure in the negative pressure chamber decreases due to the intake pipe negative pressure of the internal combustion engine,
wherein the second determining unit is configured to determine the change in the measured pressure value obtained by the pressure sensor in the state in which the negative pressure pump is operated and in a condition in which the pressure in the negative pressure chamber decreases due to the negative pressure generated by the negative pressure pump.
3 . The abnormality diagnostic device for the booster, according to claim 2 , wherein the diagnosing unit generates abnormality diagnostic information indicating that there is an abnormality in the pressure sensor, when an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the first determining unit is less than a threshold.
4 . The abnormality diagnostic device for the booster, according to claim 2 , wherein the diagnosing unit:
generates abnormality diagnostic information indicating that the pressure sensor operates normally, when an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the first determining unit is greater than a first threshold; and
generates abnormality diagnostic information indicating that there is an abnormality in the negative pressure pump, when an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the second determining unit is less than a second threshold, on the condition that it is determined that the pressure sensor operates normally.
5 . The abnormality diagnostic device for the booster, according to claim 2 ,
wherein the second determining unit is configured to determine the change in the measured pressure value obtained by the pressure sensor, in the state in which the negative pressure pump is operated, before completion of startup of the internal combustion engine,
wherein the first determining unit is configured to determine the change in the measured pressure value obtained by the pressure sensor, in the state in which the negative pressure pump is stopped, in a first idle state after the completion of startup of the internal combustion engine,
wherein the diagnosing unit:
generates abnormality diagnostic information indicating that the negative pressure pump operates normally and abnormality diagnostic information indicating that the pressure sensor operates normally, when an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the second determining unit is greater than a first threshold; and
in a case in which the amount of change in the measured pressure value obtained by the pressure sensor in the predetermined time period determined by the second determining unit is less than the first threshold, generates abnormality diagnostic information indicating that there is an abnormality in the pressure sensor, when an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the first determining unit is less than a second threshold, whereas generates abnormality diagnostic information indicating that there is an abnormality in the negative pressure pump, when the amount of change in the measured pressure value obtained by the pressure sensor in the predetermined time period determined by the first determining unit is greater than the second threshold.
6 . The abnormality diagnostic device for the booster, according to claim 2 , wherein the diagnosing unit determines whether there is an abnormality in the negative pressure pump based on an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the second determining unit, on the condition that the diagnosing unit has generated abnormality diagnostic information indicating that the pressure sensor operates normally based on an amount of change in the measured pressure value obtained by the pressure sensor in a predetermined time period determined by the first determining unit.
7 . The abnormality diagnostic device for the booster, according to claim 2 , further comprising a third determining unit configured to determine a change in a measured pressure value obtained by the pressure sensor in a condition in which the pressure in the negative pressure chamber is maintained at a predetermined negative pressure,
wherein the diagnosing unit:
receives a determination result of the third determining unit; and
on the condition that the diagnosing unit has generated abnormality diagnostic information indicating that the pressure sensor operates normally and has generated abnormality diagnostic information indicating that the negative pressure pump operates normally, generates abnormality diagnostic information indicating that a negative pressure leakage has occurred in the negative pressure chamber, when the measure pressure value obtained by the pressure sensor determined by the third determining unit increases above a set pressure.
8 . The abnormality diagnostic device for the booster, according to claim 2 , wherein at least one of the first determining unit and the second determining unit determines a change in measure pressure value obtained by the pressure sensor, after the pressure in the negative pressure chamber increases toward a positive pressure side.
9 . An abnormality diagnostic method for a booster including: a negative pressure pump that generates a negative pressure; a negative pressure chamber into which the negative pressure generated by the negative pressure pump and an intake pipe negative pressure of an internal combustion engine are introduced; and a pressure sensor that measures a pressure in the negative pressure chamber, the booster boosting a brake operating force by a negative pressure in the negative pressure chamber,
the abnormality diagnostic method comprising:
a first step of determine a change in a measured pressure value obtained by the pressure sensor, in a state in which the negative pressure pump is stopped and in a condition in which the pressure in the negative pressure chamber decreases due to the intake pipe negative pressure of the internal combustion engine;
a second step of determining a change in a measured pressure value obtained by the pressure sensor, in a state in which the negative pressure pump is operated and in a condition in which the pressure in the negative pressure chamber decreases due to the negative pressure generated by the negative pressure pump; and
a third step of receiving the change in the measured pressure value determined in the first step and the change in the measure pressure value determined in the second step, to generate abnormality diagnostic information for each of the negative pressure pump and the pressure sensor.