Heat Exchangers

Abstract

Increasing numbers of heat exchangers are used in a modern car design. Strict new governmental emissions and fuel-economy requirements drive the need for major HVAC and powertrain improvements. This, in turn, will increase the need for stricter leak testing, but also require additional high-quality heat-exchange systems. The introduction of exhaust gas recirculation adds an additional EGR cooler to each vehicle using this technology. Increased use of turbo chargers to increase gas mileage leads to increased production numbers of charge air intercoolers. For mobile air conditioners, the industry is currently switching from R134a (used as refrigerant in car air conditioners for the last decade) to the more environmentally-friendly (lower GWP), but flammable HFO-1234yf. The flammability, in particular, drives the need to test all MAC components (in this case, the evaporator and the condenser) for lower leak rates. Also, more complex designs (introduced to efficiently use the limited underhood space) restrict the use of traditional testing methods (like water bath testing).