Browse Publications Technical Papers 2017-01-1021

The New Toyota Inline 4-Cylinder 2.5L Gasoline Engine 2017-01-1021

In order to adapt to energy security and the changes of global-scale environment, further improvement of fuel economy and adaptation to each country’s severer exhaust gas emission regulation are required in an automotive engine.
To achieve higher power performance with lower fuel consumption, the engine’s basic internal design such as an engine block and cylinder head were changed and the combustion speed was dramatically increased. Consequently, stroke-bore ratio and valve layout were optimized. Also, both flow coefficient and intake tumble ratio port were improved by adopting a laser cladded valve seat.
In addition, several new technologies were adopted. The Atkinson cycle using a new Electrical VVT (Variable Valve Timing) and new combustion technology adopting new multi-hole type Direct fuel Injector (DI) improved engine power and fuel economy and reduced exhaust emissions. Variable cooling system with an electric water pump and Flow Shut Valve (FSV) improved fuel economy by reducing warm-up time and mechanical losses. Also, a newly developed variable oil pump has significantly reduced friction losses.
By implementing these new technologies, the new naturally aspirated 2.5L gasoline engine achieved over 40% thermal efficiency and over 150kW engine power. In combination with a new 8 speed Automatic Transmission, fuel consumption was reduced by over 16%.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Fuel Economy Potential of Variable Compression Ratio for Light Duty Vehicles


View Details


New 1.0L I3 Turbocharged Gasoline Direct Injection Engine


View Details


Development of the New V6 3.5L Gasoline Direct Injection Engine


View Details