Delphi’s Thermal Systems business is responsible for the group’s HVAC activities. Based in the US this division designs and produces HVAC modules and systems as well as components and engine cooling for passenger cars, other automotive and industrial applications. While at this year’s IAA show, Matthew Beecham talked with Dr Thomas Heckenberger, Vice President Engineering, Delphi Thermal Systems about technology trends in the HVAC sector.
As we understand it, the trend in automotive air conditioning has moved from manually adjusted through to semi-automatic to fully automatic, and now fully automatic dual zone for front seat passengers or even rear seat passengers. Is that still correct and where are we now?
Go deeper with GlobalData
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
Basically, that is still correct. It depends on which car segment you are looking at and that is mainly cost driven. In the very low, lower cost segment cars you still see manual air conditioning. On the other hand, we know that many people are adjusting the air conditioning incorrectly, which means they are decreasing their fuel efficiency.
Then you have the semi-automatic which features an automatic temperature control so the driver can set a certain temperature which is subsequently maintained. In addition, this system has a manual air distribution system. But we do see some incorrect system use as drivers often do not understand how best to adjust the airflow but these systems do offer a good balance of cost and comfort for many vehicles
The fully automatic offers what development engineers believe is the optimum system because it allows each parameter to be automatically set for the best comfort with the least energy consumption and noise. Certain versions feature a solar sensor which takes account of whether or not the sun is shining and on which side of the car. Here, we also talk about two, three or four zone air conditioning in order to provide a comfortable cabin environment for each occupant.
As you say, most cars appear to have air conditioning these days.
US Tariffs are shifting - will you react or anticipate?
Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.
By GlobalDataYes. Most small cars have it but it does, of course, depend on the OEM and how they define where they want to be in terms of air conditioning sophistication. For example, the VW Polo offers a semi-automatic air conditioning system.
Before we move on, I hadn’t appreciated the thermal engineer’s perspective of ‘misuse’ of the air-conditioning system by drivers. Are you saying if the driver used his or her air-con properly then they can reduce their fuel consumption?
Yes. There is a subjective part and there is a technical part. Subjectively, we cannot tell the people what is the right thing to do, since they have to feel comfortable. From an efficiency point of view, however, we know how to adjust the settings in order to achieve thermal comfort with low energy consumption. So for instance we encourage people to avoid opening the window when you run the air conditioning. Yet many people are uncomfortable with the cold airstream so they shut the outlets and open the window.
Thermal-wise, what is Delphi using this year’s IAA to highlight?
Generally, we don’t see any disruptive technology at the moment; it’s more a continuous improvement process. For example, we have developed a variable externally controlled compressor which is particularly good for small cars in emerging markets since it offers low weight and high performance.
The next development is with the start-stop approach with hybrids. With such applications, when the engine turns off at a stop light you don’t hear any noise besides the HVAC blower, which can seem loud for some drivers. So we are focusing on the HVAC blower noise/efficiency and have come up with a very good solution using new simulation techniques that allows a noise reduction of 3 to 7 dBA as well as improvements in efficiency with no increase in packaging space.
With the increasing interest in electric and hybrid vehicles from the auto manufacturers what other developments are taking place for HVAC systems in such vehicles and what is Delphi doing in this area?
We should talk about hybrids and electric vehicles separately.
On a hybrid vehicle, you still have a combustion engine; you still have a tank with a fossil or bio fuel. What does it mean? You have a storage of a high energy density, a chemical storage. That means you don’t have a lack of energy onboard. So if it’s either very cold or very hot, you can use this energy to focus on the thermal comfort. Of course the consumption will go up but in this extreme situation you still can handle that.
In a battery electric vehicle, you rely only on the energy content of the battery which is very low. That means that if you have a driving range on normal conditions – 20 degrees C outside, with no cooling or warming the cabin – you could probably travel 150 kilometres; if you do that in winter time at, say, -15 degrees C then you would just achieve 70 kilometres. Why? The rest of the energy you need to heat the cabin. That’s a big issue and why a hybrid vehicle’s HVAC is totally different from a battery vehicle.
That same holds in summer time for HVAC and in winter time for heating. HVAC consumes energy as well, not as much as heating but similar. In addition with plug-in hybrids and electric vehicles, when you are on the grid you can pre-condition the car, so you don’t need stored energy to cool it down or heat it up. On normal cars or non-plug-in hybrids, you still use the fuel. Therefore it depends on the ambient conditions, the type of car, can you plug it in or not, how you design and lay out the thermal comfort system and other factors. For example there are important safety aspects:, you have to get the windshield clear and keep it free from fogging and icing,. Therefore we do have solutions for all of this and we just recently made the whole thermal system for a the new hybrid Ferrari. So we are competent in designing those systems and providing the right components.
Earlier you mentioned stop-start and the noise related issues there but to what extent does a vehicle with stop-start impact on the effectiveness of the thermal management system?
The remainder of this interview is available on just-auto’s QUBE research service
