Catalyst control for six-cycle engine

Abstract

A six-cycle engine has the advantage for the capability of internal cooling with scavenging air. This advantage enables the compressive ratio to rise, thereby achieving lower fuel consumption. However, there has been a critical problem due to lowered temperature of the exhaust catalyst and excessive volume of oxygen contained therein caused by the mixing of the scavenging air with exhaust gas. To solve the problem of lowered temperature, the invention has thermally insulated the fuel combustion chamber and the exhausting system, and controlled the aperture degree of the scavenging port valve relatively to the suction valve to adjust the scavenging air volume against the suction air, thereby controlling temperature of the exhaust gas. Further, to solve the problem of excessive volume of oxygen, the invention has introduced an EGR (Exhaust Gas Recirculation) system to fully substitute the scavenging air with circulating exhaust gas and a self EGR system to open the exhaust valve during the scavenging air introduction stroke. The present invention has successfully made a naturally good fuel-efficient six-cycle internal combustion engine be suited one for practical use such as conventional vehicles.

1 - 10 . (canceled) 
     
     
         11 . A six-cycle engine having a suction port and a scavenging port, comprising a system that can substitute exhaust circulating gas for the entire volume of scavenging gas. 
     
     
         12 . The six-cycle engine of  claim 11 , further comprising a first valve disposed to the suction port and an second valve disposed to the scavenging port, said valves including means for operating in connection with accelerating operation and means for relatively varying aperture degrees of the first valve and the second valve by operation of an actuator. 
     
     
         13 . A premix six-cycle engine having an suction port and a scavenging port comprising a suction valve and a scavenging valve both being opened during an suction stroke. 
     
     
         14 . The six-cycle engine of  claim 12 , being configured as a direct-injection six-cycle engine having a suction valve to be open during a scavenging air introduction stroke, the direct-injection six-cycle engine further comprising a continuous variable valve timing system to vary the aperture degree of the suction valve during the scavenging air introduction stroke. 
     
     
         15 . A valve control system for the six-cycle engine of  claim 12 , comprising means for detecting temperature of an exhaust catalyst and means for driving the actuator to relatively control the aperture degrees of the first valve and the second valve in accordance with the temperature of the exhaust catalyst. 
     
     
         16 . The six-cycle engine of  claim 12 , further comprising: an scavenging port valve in the upstream of the scavenging port in addition to the second valve; and an port disposed to the middle position between the scavenging port valve and the second valve for circulating and supplying exhaust gas from an exhaust port. 
     
     
         17 . A valve control system for the six-cycle engine of  claim 16  having a computer for controlling the scavenging port valve, said computer comprising: means for detecting the conditions of the exhaust catalyst; means for detecting the aperture degree of the first valve; and means for driving an actuator to vary the aperture degree of the scavenging port valve. 
     
     
         18 . A valve control system for the six-cycle engine of  claim 14 , comprising means for detecting temperature of an exhaust catalyst and means for driving the actuator to relatively control the aperture degrees of the first valve and the second valve in accordance with the temperature of the exhaust catalyst. 
     
     
         19 . The six-cycle engine of  claim 14 , further comprising: an scavenging port valve in the upstream of the scavenging port in addition to the second valve; and an port disposed to the middle position between the scavenging port valve and the second valve for circulating and supplying exhaust gas from an exhaust port.