Liquid Cooled Charge Air Coolers Reduce Vehicle Emissions and Improve Fuel Consumption
Boosted Engines Benefit From Lower Intake Temperatures and Improved Response With Superior Engine Bay Packaging
A new range of liquid cooled charge air coolers (LCCACs) from Delphi Corp. will help global vehicle manufacturers of both gasoline and diesel engines produce environmentally-friendly vehicles with better engine performance. Compared to existing air-cooled units, the new coolers offer better packaging, improved engine response, faster warm-up and lower losses.
"Our new generation of charge air coolers will help vehicle manufacturers meet future targets for tailpipe emissions and improved fuel economy with cars that are still fun to drive," said Steve Kiefer, director of engineering, Delphi Thermal Systems, Delphi Corp.
In order to combine reduced tailpipe emissions, improved fuel economy and maximum driver satisfaction, vehicle manufacturers are turning to downsized engines. Boosted by turbo- or super-charging, these engines give the performance feel of a larger engine with the emissions and fuel savings of a smaller one. However, boosting compresses the air entering the engine, which significantly increases the air temperature, greatly reducing combustion efficiency and eroding the performance improvement. Delphi addresses this by introducing a charge air cooler into the intake system; Delphi manufactures a wide-range of air-cooled charge coolers and is now developing a portfolio of new liquid cooled heat exchangers that offer more flexibility in their installation.
The versatility of Delphi's LCCAC technology also allows the coolers to be incorporated into the ducting between the turbo/super charger and the engine or integrated into the intake manifold, minimizing air-pressure losses through the cooler and improving engine bay layout. To provide vehicle manufacturers with additional packaging flexibility, Delphi's wide range of heat exchangers can be modified for specific applications to fit any size and shape of engine.
Unlike an air-to-air charge cooler, a LCCAC requires no large diameter elastomeric tubing to route the charge air to and from the cooler, further improving packaging and eliminating large diameter connectors that can lead to warranty problems. Engine response to sudden throttle demand is improved because of the smaller volume of intake air between the boosting device and the engine in a liquid cooled system. Additionally, the intake air stays cooler during acceleration because the liquid cooled charge cooler heats up more slowly. This higher thermal capacity also helps to limit peak NOx emissions during transient driving conditions by maintaining cooler inlet air temperatures.
Further emissions benefit is derived under cold start conditions, as coolant flow to the LCCAC can be limited to increase engine warm-up rate. On gasoline engines, during partial load conditions when engine efficiency falls due to throttling losses, coolant flow can also be limited to heat the intake air, reducing its density and allowing a greater opening of the throttle valve and, hence, reducing the losses.
"We expect to have the first Delphi liquid cooled charge air coolers in production during 2011," Kiefer said.
Delphi is a leading global supplier of electronics and technologies for automotive, commercial vehicle and other market segments. Operating major technical centers, manufacturing sites and customer support facilities in 30 countries, Delphi delivers real-world innovations that make products smarter and safer as well as more powerful and efficient. Connect to innovation at www.delphi.com.