A soft absorption stem for an electronic cigarette is provided, comprising a sleeve, a cigar liquid tank disposed inside the sleeve, an atomization device and a liquid guiding component. The lubrication system may include an oil pan configured to receive oil from the engine. The first wall and the second wall each have an inner surface facing the fluid chamber and an opposed outer surface. An internal combustion engine includes an electrical actuator configured to control opening or closing of one of an intake valve and an exhaust valve. The removal of key impurities either before the first crystallization or between the first and second crystallizations facilitates the crystallization of product to produce a higher yield of product.