Jet-Spray Oil Cooling(SATURN)

 Jet-Spray Oil Cooling

GM engineers said the engine’s oiling system delivers pressurized oil to continuously lubricate and cool the pistons, which reduces friction and noise. It’s also designed to ensure durability for the engine’s higher power levels. To enhance combustion, the piston tops feature a dish shape that deflects injected fuel toward the spark plugs.

To accommodate the direct injection system, the Ecotec Turbo has a unique cylinder head and intake manifold. The cylinder head incorporates mounting locations for the fuel injectors — which are typically mounted in the intake ports or intake manifold on port injection engines. A high-pressure fuel pump delivers fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through precision multi-hole fuel injectors. The fuel pump, fuel rail pressure, fuel injection timing and injection duration are controlled by the engine control module. In this way, the fuel is metered and delivered in a finely atomized spray.

Apart from the mounting positions of the fuel injectors, the cylinder head has conventional port and combustion chamber designs, although both are optimized for direct injection and high boost pressures. The sodium-filled exhaust valves and stainless steel exhaust manifold are durable components designed to stand up to the high-performance capability of the engine.

The unique cylinder head, fuel system, pistons, intake manifold and the dual-scroll turbocharger are the only major components that differentiate the 2.0L Turbo from other members of the Ecotec engine family.

Ecotec 2.0L Turbo engine highlights:
• Steel crankshaft
• Forged connecting rods
• Cast aluminum oil-galley pistons
• Jet-spray piston cooling
• 9.2:1 compression ratio
• Aluminum cylinder head with sodium-filled exhaust valves
• High-pressure engine-driven fuel pump
• Variable pressure fuel rail
• Dual-scroll turbocharge 

   

 Turbocharging System

 
A unique, dual-scroll turbocharger is partnered with an air-to-air intercooling system to provide up to approximately 20 psi of power-enhancing boost. The dual-scroll turbocharger delivers nearly instant response, as dual exhaust passages from the engine to the turbine housing guide exhaust gas to the turbine. This reduces lag time, or spool-up, at low rpm.

The turbocharger is matched to the engine’s displacement and performance objectives. It’s supported by the air-to-air intercooling system, which uses fresh air drawn through a heat exchanger to reduce the temperature of the warmer compressed air forced through the intake system by the turbocharger. Inlet temperature is reduced by approximately 212° F (100° C), enhancing performance because cooler air is denser and promotes optimal combustion.

 

Dual Cam Phasing

The camshafts of the Ecotec Turbo ­engine have phasers that support the continuously variable intake and ­exhaust valve timing. They also have cam position sensors, so that the engine control module can accurately control valve timing. The crankshaft and camshaft position sensors are digital. A new engine controller, specific to the ­engine, is used to sense and control the engine’s performance parameters.

Variable intake and exhaust timing works synergistically with both the gasoline direct injection and turbocharging systems. The variable engine timing enabled by cam phasing allows the combustion process to be optimized. Also, valve “overlap” at low rpm can be adjusted by the controller to increase the response of the turbocharger, providing a more immediate feeling of power.

Family Ties

The Ecotec 2.0L Turbo was built on a global platform that was designed at the outset for a range of performance and combustion capabilities. The Gen II block supports the high-performance demands of the engine, but it is merely a strengthened version of the original Ecotec architecture. The oil pump, mentioned earlier, is the same as those used in all other Ecotec engines, and was originally designed to support high-performance applications of future engines.

As with other engines in the Ecotec family, the turbo version also has premium features designed to ensure smooth and quiet operation, including a polymer coating and skirt design for the pistons that reduces noise during cold starts. An automatic hydraulic tensioner also is used to maintain optimal tension on the timing chain, which reduces noise and vibration.

Some of the other traits the turbo design shared with the other Ecotec platforms include:
• Dual overhead camshafts (DOHC) and four valves per cylinder;
• Twin counter-rotating balance shafts for operational smoothness;
• Electronic throttle control;
• Low-friction, roller-finger follower valvetrain with hydraulic lash adjusters;
• Low-maintenance chain-drive for the camshafts;
• 58X crankshaft positioning;
• Direct-mount accessories, which reduce or eliminate traditional sources of noise and vibration; and 
• Full-circle transmission mount to reduce noise and vibration.