Abstract A crankcase ventilating system adapted to effectively reduce the amount of hydrocarbon exhaust during idling and decleration. This system has a first conduit through which blow-by gases containing water and gasoline vapors in the crankcase enter the throttle chamber upstream of the throttle valve. The first conduit is provided with an orifice which controls the flow therethrough. A second conduit is provided to introduce fresh air from the air cleaner to the crankcase. During idling and deceleration the throttle valve is held in the fully closed position so that the blow-by gases are prevented from entering the engine. Under these conditions, only a small amount of blow-by gases is caused to flow into the air cleaner through the second conduit by an extremely small negative pressure existing in the air cleaner. Thus, the amount of hydrocarbon exhaust during idling and deceleration is remarkably reduced.
In a fuel injection type internal combustion engine adapted for reducing the amount of unburned hydrocarbons in exhaust gases from said internal combustion engine during idling and decelerating conditions of said engine and having a throttle chamber, a combustion chamber and a crankcase, the improvement comprising, in combination, a throttle valve disposed in said throttle chamber and adapted to be fully closed during idling and decelerating conditions of said engine, an idle circuit having a passage formed in a casing of said throttle chamber for admitting a small amount of air into said combustion chamber during idling and decelerating conditions of said engine, and a connecting tube having one end connected to said crankcase and the other end connected to said throttle chamber upstream of said throttle valve to permit blow-by gases and fuel vapors in said crankcase to pass into said throttle chamber upstream of said throttle valve, said throttle valve preventing the blow-by gases and the fuel vapors passed into said throttle chamber from entering said combustion cylinder during idling and decelerating conditions of said engine.
Claim 2
Dependent Claim
178 words
In a fuel injection type internal combustion engine adapted for reducing the amount of unburned hydrocarbons in exhaust gases from said internal combustion engine during idling and decelerating conditions of said engine and having a throttle chamber, a combustion chamber and a crankcase, the improvement comprising, in combination, a throttle valve disposed in said throttle chamber and adapted to be fully closed during idling and decelerating conditions of said engine, an idle circuit having a passage formed in a casing of said throttle chamber for admitting a small amount of air into said combustion chamber during idling and decelerating conditions of said engine, and a connecting tube having one end connected to said crankcase and the other end connected to said throttle chamber upstream of said throttle valve to permit blow-by gases and fuel vapors in said crankcase to pass into said throttle chamber upstream of said throttle valve, said throttle valve preventing the blow-by gases and the fuel vapors passed into said throttle chamber from entering said combustion cylinder during idling and decelerating conditions of said engine.
Claim 3
Dependent Claim
32 words
The improvement according to claim 1, further comprising an orifice formed in said connecting tube to control the flow rate of said blow-by gases and said fuel vapors through said connecting tube.
Claim 4
Dependent Claim
43 words
The improvement according to claim 1, further comprising a connecting tube having one end connected to an air cleaner of said internal combustion engine and the other end connected to said crankcase for introducing fresh air from said air cleaner to said crankcase.