Patent ID: 8095289

Claim:
A negative braking pressure control apparatus comprising: a main intake air passage, which is branched into intake manifolds for supplying intake air into respective cylinders; a respective throttle valve provided in each of the intake manifolds for respectively controlling an intake air amount; a respective communication passage connected to each of the intake manifolds at a downstream side of the throttle valve, in order to generate a negative braking pressure for a brake booster; a negative pressure control valve provided in a negative pressure pipe, wherein the communication passages for the respective cylinders are converged to the negative pressure pipe; a negative pressure control means for operating the negative pressure control valve and thereby controlling the negative braking pressure of the brake booster in accordance with an operational condition of the engine; an air ejector provided in the negative pressure pipe; a negative pressure passage for the brake booster, wherein the brake booster connected to a suction side of the air ejector via the negative pressure passage, and wherein the negative pressure passage includes a check valve; a gas passage for crankcase ventilating gas, which is connected at a driving gas side of the air ejector; and a branched intake air passage connected at the driving gas side of the air ejector for distributing a part of the intake air in the main intake air passage upstream of the throttle valve, wherein the negative pressure control valve is provided in the intake air branched passage.