A hydraulic system comprises a pump, low pressure drain, high pressure rail, fuel injector, a gas exchange valve actuator, and a timing valve. The high pressure rail is connected to the pump with a supply line. A method of operating an engine comprises the steps of opening a gas exchange valve by connecting...http://www.google.co.uk/patents/US6769405?utm_source=gb-gplus-sharePatent US6769405 - Engine with high efficiency hydraulic system having variable timing valve actuation
