This 2001 report covers a detailed design benchmarking study of the Subaru H4 2.0L gasoline engine and includes a photographic record of all the main components, plus individual masses and dimensions. Ricardo comments on specific design features are also included.
The Subaru EJ20 engine was designed as part of a family of horizontally opposed 4 cylinder gasoline engines, introduced in 1990. The family includes naturally aspirated and turbocharged versions with capacities ranging from 1.8 to 2.5 litres. All feature 4 valves per cylinder operated by either a single overhead camshaft or double overhead camshafts. Because of the inherently good balancing and vibration characteristics of the horizontally opposed 4 cylinder engine, no balancer shafts are required. This helps to reduce engine weight, friction, complexity and manufacturing cost.
Although the engine length is short, the width is large and hence packaging between the vehicle side members and front wheel arches is critical. This is a major reason for the very over-square cylinder dimensions in order to achieve a short stroke.
This engine has a maximum power of 155kW (211hp) at 6000rpm and a maximum torque of 270Nm at 4800rpm.
- Cylinder Block, Cylinders, Crankcase and Main Bearing Structure
- Connecting Rod, Bearings
- Piston, Pin and Rings, Cylinder Head and Ports
- Camshafts, Valve Train and Cam Cover
- Inlet, Exhaust and Emission Control System