| 摘要 |
<P>PROBLEM TO BE SOLVED: To estimate pressure in a brake booster with a high degree of accuracy. <P>SOLUTION: In the brake booster 15, a check valve passage flow rate (a flow rate of gas passing through a check valve 21), an atmospheric valve passage flow rate (a flow rate of gas passing through an atmospheric valve 22), and a vacuum valve passage flow rate (a flow rate of gas passing through a vacuum valve 23) are changed depending on intake pipe pressure changing according to an operating condition of an engine 11 and a stroke amount changing in accordance with treading of a brake pedal 24; and conditions (number of moles and volume of the gas) in a constant-pressure chamber 19 and a variable-pressure chamber 20 are changed to change constant-pressure-chamber internal pressure Pb (pressure in the constant-pressure chamber 19) and variable-pressure-chamber internal pressure Pc (pressure in the variable-pressure chamber 20). Thus, the check valve passage flow rate, the atmospheric valve passage flow rate and the vacuum valve passage flow rate are computed on the basis of intake pipe pressure and the stroke amount, and the constant-pressure-chamber internal pressure Pb and the variable-pressure-chamber internal pressure Pc are estimated on the basis of the flow rates. Consequently, the constant-pressure-chamber internal pressure Pb and the variable-pressure-chamber internal pressure Pc can be accurately estimated even in a transient state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
