Toyota’s New 1AR 4-Cylinder Engine

4-cylinder engines are a key component of Toyota’s engine lineup, and the new 2009 Toyota Venza delivers the newest entry into this lineup, the 2.4 liter 1AR-FE engine.

Developed in response to today’s severe economic and fuel efficiency conditions, the new 4-cylinder engine offers two different displacements for the first time in a North America passenger car with more than 2.4 liters. This helps to achieve both good performance and low emissions, even in larger vehicles. The first technological advance begins upon ignition. During start-up and engine idling warm-up, the newly designed Tumble Control Valve (TCV) allows faster catalyst light-off, resulting in reduced emissions. When the TCV valves are fully closed, hydrocarbons (HC) are reduced, and a strong tumble flow is generated in the cylinders, helping to achieve clean emissions and strengthening tumble by reducing intake air passage. When the valves are fully open, the intake resistance is decreased, achieving enhanced engine performance and maximum power.

Kaizen (continuous improvement) and innovative technologies were implemented to achieve best in class in fuel economy and performance. One way to increase fuel economy is to reduce friction, therefore a lower friction Roller Rocker Valvetrain was incorporated which, when compared to direct bucket systems, resulted in improved fuel economy. The Variable Displacement Oil Pump is engineered to deliver oil based on the demands of the engine. The result of this engineering is lower friction under most engine operating conditions which, in turn, improves fuel efficiency.

Another new technology feature of the AR engine family is a Catalyst Washcoat, which is more resistant to higher temperatures. The increased resistance of the Catalyst Washcoat improves durability and increases the range of stoichiometric engine operation - another contributor to increased fuel economy. Finally, an Independent Intake and Exhaust VVT-i was installed to maximize engine breathing for best performance, lowest pumping losses for best efficiency, and also to minimize cold HC emissions.

The new 1AR engine reflects Toyota’s philosophy of kaizen by meeting today’s challenging environmental changes and addressing tightened emission and fuel efficiency regulations.

The new 4-cylinder engine offers two different displacements for the first time in a North America passenger car with more than 2.4 liters.