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Cooled LPL EGR is a proven means of improving the efficiency of a Gasoline Turbocharged Direct-Injection engine. One of the most significant hurdles to overcome in implementing a LPL EGR system is dealing with condensation of water near the entrance of the turbocharger's compressor wheel. A gasoline engine, and to a greater extent a spark ignition engine running on Natural Gas, will encounter enough water condensation at some steady-state conditions to damage the compressor wheel due to the high-speed collision between the compressor blades and the water droplets. As an alternative to not utilizing beneficial EGR at the condensing conditions, the team at BorgWarner have developed a LPL EGR mixer that is effective at condensing and collecting the water droplets and routing the water around the compressor wheel. The new Condensing EGR mixer was developed from the known concept of utilizing a mild venturi section to enhance EGR delivery and mixing.

Dynamic analysis has shown that for a V-6 engine with a DOHC valvetrain layout, a Cam Torque Actuated phaser can be actuated rapidly enough to have the net effect of retarding the valve opening and advancing the valve closing within one valve event, hence; reducing the event duration. Reducing the cam duration from the fixed cam-lobe duration can have benefits at Cold-Start, Cold-Idle, Hot Engine Idle, and low-speed Part-Throttle operation. The approach taken for this investigation was to model the duration-reduction system at engine cranking speeds with GT-Power. Engine simulation showed that we can achieve sonic velocity at the valve seat at engine cranking speeds, and concurrently maximize the effective compression ratio. Based on these promising results, a prototype system was built and tested. A dyno-based test was devised to simulate repeated cold-start first-firing cycles to examine the effect of the system on lean ignition limit and cumulative HC during a cold-start.

Prior work with the concept of dividing the exhaust process into an early and late phase has shown the potential of applying only the early stage (blow-down) of the exhaust period directly to a turbocharger or turbocharger system, and the later stage (scavenge) arranged to bypass the turbine. In this manner, the exhaust backpressure required to extract high turbine work from the engine can be isolated from the displacement phase of the exhaust stroke and thereby greatly reduce the exhaust pumping work and Residual Gas Fraction. In previously-published efforts, the challenges of valve-event control and high turbine inlet temperature have been revealed. The BorgWarner Engine Systems Group, in conjunction with Presta, has applied a cam-phaser controlled concentric camshaft system to the exhaust side of a divided exhaust port 4-valve per cylinder DOHC GDI engine, to enable variable phasing between the Blow-down and Scavenge cam profiles.