In this interview, Matthew Beecham talked with Gabriele Maione, R&D manager, engine cooling systems and components, Denso Thermal Systems SpA.
just-auto: Could we start by asking if you could sum-up the factors driving the automotive powertrain cooling sector?
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Gabriele Maione: Carmakers’ requests for engine cooling systems are increasingly pushing suppliers to find new solutions. Cost reduction is always a key point for carmakers, but in recent years environmental requirements have also become very important. New European regulations are aimed at reducing pollutant emissions, and carmakers are searching for any device that will achieve new standards. Engine downsizing is one of the solutions identified by carmakers, but thermal management is also important in order to reduce fuel consumption and emissions.
just-auto: Demands on powertrain cooling product performance are continually increasing. In addition, automakers expect economical solutions that help reduce emissions from cars and trucks. With these demands in mind, how has Denso responded?
Gabriele Maione: Denso is continuously working with carmakers to improve the standard of its parts and systems, in order to meet their performance requirements and dimension for new engines, as well as meeting tighter safety regulations.
New engine cooling systems and thermal management systems are under development in collaboration with carmakers. Denso is also working with European university and research centres to build the vehicles of the near future.
just-auto: As you know, packaging is becoming tighter in the vehicle front-end resulting in the requirement for more efficient heat exchangers. How have you responded to that?
Gabriele Maione: Pedestrian impact regulations and insurance tests are becoming ever more stringent. Car manufacturers and suppliers therefore have to join efforts to fit the increasing number of components under the bonnet, and meet European regulations. To do so, Denso is studying new heat exchangers with higher specific heat rejection, i.e. higher heat exchanged per surface unit. This may lead to smaller heat exchangers that can be more easily fitted into the front-end.
Engine module fixations also have to be changed to aid damage reduction and serviceability.
Moreover, Denso is developing indirect exchangers (e.g. water-cooled CAC) that can be positioned under the bonnet to make the front end module simpler and lighter.
just-auto: In what ways does the EGR impact on the engine cooling system?
Gabriele Maione: The increased heat load in the engine cooling circuit caused by adding the EGR heat rejection needs more powerful systems to be implemented.
just-auto: Although hybrids have not really created a substantial change in the heat transfer philosophy of the engine, has this technology created the need for additional product on the electronic side of things?
Gabriele Maione: Internal combustion engines and electrical motors work at different temperature levels to achieve their best performance. Whilst an internal combustion engine usually works at 90°C coolant temperature, the colder an electrical motor is, the better it works. For this reason hybrids need a separated cooling circuit. New battery concepts and electronics add more specific issues to the design of electrical part of cooling system. From the layout point of view, a new radiator has to be added to the cooling module to reject the electrical motor load, resulting in a more complex front-end cooling module.
just-auto: Generally speaking, in respect of fuel economy, is there a trend toward more use of electronics to try to more closely monitor engine temperature for maximum efficiency? i.e. perhaps using electronic thermostats and electronic water pumps to completely take control of the heat rejection itself. But I guess there is always a trade-off the carmaker must make between adding weight and cost (through electronics) and saving fuel.
Gabriele Maione: Fuel economy is attracting more and more interest from carmakers. This is largely due to the new environmental laws that fix limits on pollutant emissions and incur fines for any transgression. Carmakers and suppliers are considering a very wide range of devices to reduce fuel consumption. Electronics can help the engine temperature to warm up faster, for example, to reduce friction and cold start problems. Working together, carmakers and suppliers are evaluating the effects of such devices to understand both the benefits and the costs. This is not only related to fuel economy; use of these devices has also some indirect benefits. For example, the electrical water pump can avoid overheating at engine shutdown.
just-auto: With pedestrian safety laws swinging into force in Europe, how does that impact on engine cooling system design? i.e. smaller modules, thinner radiators, etc.
Gabriele Maione: Design engineers have always designed engine cooling systems with a small air intake in order to reduce vehicle drag. The introduction of pedestrian safety laws is making this problem slightly worse. Carmakers are increasingly demanding ever smaller and lighter engine cooling modules. Denso is therefore developing new heat exchangers with higher specific heat rejection, to meet these car manufacturers’ requirements. Developing new systems such as indirect CAC or indirect condensers can also help to reduce the cooling module depth, in order to meet safety pedestrian regulations.
just-auto: The popularity of diesel engines in the European market coupled with the new emission standards is presumably causing new developments in charge air coolers. Any observations there in terms of what is happening with charge air coolers? And how has Denso responded in terms of innovations?
Gabriele Maione: At Denso, charge air coolers are following the same development path of radiators in terms of improving specific heat and weight loss. In contrast to radiators, however, they have to withstand higher temperatures and pressures as well as an acid environment, due to low pressure loop EGR. The downsizing trend is also pushing for higher temperatures and pressure, in order to achieve the same engine performance as bigger engines.
Denso is currently developing a new type of water-cooled charge air cooler. This type of charge air cooler is more compact than an air-cooled one, and can be positioned anywhere under the bonnet. This means it can be removed from the front end, with resulting benefits in pedestrian safety. The new cooler can be installed and integrated into the air intake manifold as a single component; reducing the length of the charge air lines and thereby reducing pressure losses.
