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We developed a novel method for reducing the engine noise associated with the high-pressure fuel system in gasoline direct-injection (DI) engines. We focused on the level of noise at idle running speed, because at the idle state, engine noise is the only noise source to the driver. The dominant vibration source of the high-pressure fuel system was fuel pulsation from the high-pressure fuel pump and activation noise of the solenoid-drive injector. To reduce the noise of the idling engine, we focused on the vibration transmission path from the high-pressure fuel system to the cylinder head, which results in noise radiation from the engine block. Next, we focused on the radiation noise associated with the pressurization event of the high-pressure fuel pump. To reduce the vibration transmission from the high-pressure fuel system to the cylinder head, the fuel rail and the injector were isolated from the cylinder head by avoiding metal-to-metal contact.

To meet the requirements for higher horsepower and torque as well as lower fuel consumption and emissions, we have developed a new “Intelligent Variable Valve Timing (VV-i)” system. It gives continuously variable intake cam phasing by up to 60 degrees crank angle (CA) . This system not only increases WOT output by optimizing intake valve closing timing but also reduces fuel consumption and NOx/ HC emissions under part load by increasing intake and exhaust valve overlap on 4 stroke Spark Ignited engines. VVT-i has been applied to optimize a new 3-liter inline 6 engine for higher torque and at the same time better fuel economy with continuous and wide-range cam phasing.