ES300 — NEW FEATURES 10 3. Major Differences The following changes have been made to the 1MZ-FE engine. System Features Engine Proper • The cylinder block and the crankshaft have been made more rigid to realize a quieter operation. • The shape of the back of the cylinder head and of the cylinder head cover has been changed in conjunction with the adoption of the VVT-i system. Valve Mechanism • The VVT-i system is used to improve fuel economy, engine perfor- mance and reduce exhaust emissions. • The valve lift of the camshaft has been increased and the valve tim- ing has been changed to improve engine performance.
Lubrication System The capacity of the oil pump has been improved to accommodate the adoption of the VVT-i system, which is hydraulically actuated. Cooling System The direction of the rotation of the electric cooling fan has been re- versed. Intake and Exhaust System • Compact plug-in type mass air flow meter is used. • 3-stage ACIS (Acoustic Control Induction System) is used to deliv- er high power output in all engine speed ranges. • A 2-valve throttle body has been adopted to accommodate the 3-stage ACIS. • A double-wall construction exhaust manifold made of stainless steel has been adopted on all models.
• The distance to the convergence of the front exhaust pipe has been lengthened and the shape of the convergence has been optimized to improve engine output. • A ball joint has been adopted for the connection between the front exhaust pipe and the center exhaust pipe, as well as between the cen- ter exhaust pipe and the tailpipe to reduce noise and vibration. • A 3-way exhaust control system has been adopted to improve engine performance and to ensure an even quieter operation. Fuel System ORVR (On-board Refueling Vapor Recovery) system is used to reduce the amount of fuel vapor that is discharged to the atmosphere during refueling.
Ignition System • A DIS (Direct Ignition System) that uses ignition coils with a built- in igniter for each cylinder has been adopted. • Iridium-tipped spark plugs have been adopted to improve ignition. Engine Mount An active control engine mount is used on the front engine mount and a liquid-filled compound mount is used on the rear engine mount. Engine Control System • Control for the VVT-i and the 3-stage ACIS systems has been added. • The EGR control system has been discontinued in conjunction with the discontinuance of the EGR system. Emission Control System A service port has been provided for inspecting the evaporative emis- sion control system.