Air intake system for diesel engine
AssigneeHitachi, Ltd.
InventorsAkiyasu Kuwahara, Syozo Yanagisawa
Life of this patent
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Abstract
An air intake system for a Diesel engine has an air intake passage defined by a tubular wall in which EGR openings are formed for the recirculation of engine exhaust gases. The rate of the flow of the exhaust gases through the EGR openings is controlled by EGR valve which is rotatable with a throttle valve disposed in the air intake passage. Either when the engine temperature is lower than a predetermined temperature level or when the vacuum in the air intake passage downstream of the throttle valve with the latter being in its idle position exceeds a predetermined vacuum level in absolute value, either a bypass passage is open or the throttle valve is moved from the idle position to a more opened position, whereby the engine intake air is increased.
Claims17
An air intake system for a Diesel engine, comprising:
- a main body defining therein an air passage;
- a throttle valve pivotally mounted in said air passage;
- at least one EGR opening formed in the peripheral wall of said air passage for the recirculation of engine exhaust gases back into said air passage;
- an EGR valve means operatively associated with said throttle valve to vary the rate of the flow of the recirculated exhaust gases through said EGR opening in accordance with the operating conditions of the engine;
- said EGR opening being at least partially open by said EGR valve means when said throttle valve is in its idle position;
- wherein the improvement comprises means for increasing the rate of the flow of intake air into said engine when the engine is at a temperature lower than a predetermined temperature.
An air intake system for a Diesel engine, comprising:
- a main body defining therein an air passage;
- a throttle valve pivotally mounted in said air passage;
- at least one EGR opening formed in the peripheral wall of said air passage for the recirculation of engine exhaust gases back into said air passage;
- an EGR valve means operatively associated with said throttle valve to vary the rate of the flow of the recirculated exhaust gases through said EGR opening in accordance with the operating conditions of the engine;
- said EGR opening being at least partially open by said EGR valve means when said throttle valve is in its idle position;
- wherein the improvement comprises means for increasing the rate of the flow of intake air into said engine when the vacuum in said air passage downstream of said throttle valve with the latter being in a predetermined position substantially corresponding to its fully closed position is increased beyond a predetermined vacuum level.
Dependencies are inferred from the claim text.