Abstract: A positive crankcase ventilation (PCV) valve installation structure for installing a PCV valve of an engine on an engine body includes: a blow-by gas recirculation system that includes a ventilation hose that connects the engine body to an intake device introducing outside air into the engine body and that has a recirculation passage recirculating blow-by gas arising in the engine body to the intake device and an oil cooler device that exchanges heat between lubricating oil and a medium solution that is lower in temperature than the lubricating oil; and a cover that transfers heat of the oil cooler device to the PCV valve.

Abstract: A positive crankcase ventilation (PCV) valve installation structure for installing a PCV valve of an engine on an engine body includes: a blow-by gas recirculation system that includes a ventilation hose that connects the engine body to an intake device introducing outside air into the engine body and that has a recirculation passage recirculating blow-by gas arising in the engine body to the intake device and an oil cooler device that exchanges heat between lubricating oil and a medium solution that is lower in temperature than the lubricating oil; and a cover that transfers heat of the oil cooler device to the PCV valve.

Abstract: An internal combustion engine is provided that includes a combustion chamber; a secondary air passage located above the combustion chamber; an exhaust passage that communicates with the combustion chamber; and a water jacket that is located between the exhaust passage and the secondary air passage.

Abstract: An internal combustion engine is provided that includes a combustion chamber, a secondary air passage located above the combustion chamber; an exhaust passage that communicates with the combustion chamber, and a water jacket that is located between the exhaust passage and the secondary air passage.

Abstract: A valve characteristic control apparatus for controlling the operation characteristics of the valves of an internal combustion engine driven by a camshaft is disclosed. A working oil supply control valve is arranged in a support member for supporting the camshaft. A first oil path and a second oil path for leading the working oil from the working oil supply control valve to the first and the second oil chambers include an annular first oil path and an annular second oil path formed in the camshaft and the slide portion of the support member for pivotally supporting the camshaft, a first and a second in-support member oil path for connecting the annular first oil path and the working oil supply control valve and for connecting the annular second oil path and the working oil supply control valve.