A better environment with electrical preheating

An increasing number of international studies reveal that cold starts are the leading cause of harmful emissions from cars. This is true even for the newest vehicles on the market. These emissions contribute to poor air quality in the cities, which in turn impact the health of everyone living there. The good news is that the same studies show that electrical preheating is a useful tool in combating cold starts and their effects.

One recent study on the effect of cold starts was performed by researchers at Berkeley, Carnegie Mellon, University of California and MIT. This study showed that modern petrol cars release the same amount of harmful emissions in the first 30 seconds after a cold start as in 300 kilometers of driving with a warm engine.

• See report

Another test, performed by VTT – the independent state research institute of Finland, found that electrical preheating can reduce harmful emissions by as much as 71% in cold conditions.

See reports:

• Defa Energy Test D4
• Defa Energy Test D5
• Defa Energy Test F1
• Defa Energy Test F3

Furthermore, the Swedish Road and Transport Research Institute (VTI) concludes that significant cuts in emissions can be achieved through increased use of electrical preheating.

• See report

The consensus is the same in Norway, where both the Institute of Transport Economics (tøi) and the Norwegian Automobile Association (NAF) recommends the use of electrical preheating to lower emissions.

What is a cold start:

Whenever an engine is started temperatures below +10 centigrade without prior heating, it is considered a cold start. Under these conditions, emissions will always be elevated, but they become progressively higher as temperatures get lower. A cold started engine will emit considerably more at -10 degrees than at +10 degrees.

How cold starts lead to increased emissions:

To understand why the impact of cold starts is so significant, one must first understand its effects. The total increase in emissions after a cold start is a result of several factors. All of these factors play an increasing role as the temperature gets lower.

• The cold makes the oil too viscous. The lack of proper lubrication leads to increased friction and a less efficient engine. This, in turn, leads to increased fuel consumption and emissions.
• A cold engine is supplied with more fuel by design. This elevated consumption is maintained until the engine reaches optimal operating temperature.
• The catalyst must be warm to function adequately. The catalyst removes harmful particles and gases from the exhaust, but it only works once the exhaust has heated it. The increased infusion of fuel into a cold engine is partly designed to heat the catalyst more quickly.
• The battery is drained in the cold and is recharged through additional fuel consumption. If you don’t charge the battery before you start driving, the generator must recharge it while you drive. Since the generator runs by burning extra fuel, this increases emissions. With cold weather, short drives, frequent use of comfort functions like defrosters, seat heaters and fuel heaters, the batteries in many cars are continuously being drained and never fully recharged. A continuously running generator leads to increased emissions.

How electrical preheating lowers emissions:

An electrical preheating system consists of an engine heater, an interior heater, a battery charger and app control, all of which contribute to reducing emissions.

The engine heater heats the engine and motor oil, ensuring that the engine is well lubricated, leading to reduced friction and optimal efficiency.

The interior heater raises the temperature in the cabin to a comfortable level. This melts the ice and snow of the windows and reduces the need for power-hungry comfort functions like defrosters, seat heaters and fuel heaters.

The battery charger charges the battery before you start driving. In combination with the reduced use of comfort functions, this means that the battery requires less charging during driving. Less fuel used to run the generator means lowered emissions.

The app control system helps you make sure that no excess energy is used to heat the car. The user can easily program the system to heat the vehicle in time for regular departure times. The system automatically determines when to start heating based on the outside temperature.

Massive reductions with electrical preheating:

In the test performed by VTT in Finland, regular Euro 5 petrol and Euro 6 diesel cars were tested against identical models outfitted with DEFA’s electrical preheating system WarmUp. The test considered the first 20 minutes of driving after a cold start at -20 degrees. Some important findings are presented below:

Petrol EURO 5	Co2 (g/km)	PM (mg/km)	NOx (g/km)
Cold start	306	152	0,35
Preheated	253	12	0,17
Reduction	17%	92%	52%

 

DIESEL EURO 6	Co2 (g/km)	PM (mg/km)	NOx (g/km)
Cold start	254	<1	0,97
Preheated	198	<1	0,60
Reduction	22%	0%	38%

Key findings:

• Electrical preheating can reduce the emissions of PM from petrol cars by up to 92%. PM is very harmful to health and a primary driver of poor air quality in the cities.
• Electrical preheating can reduce the emissions of NOx from petrol cars by up to 52% and from diesel cars by up to 38%. The percentage-wise decrease was most substantial for petrol cars, but the effect in g/km will be more substantial for diesel cars (-37 g/km vs. -18 g/km). The reason is that they emit more NOx.
• Electrical preheating can reduce emissions of Co2 from petrol cars by up to 17% and from diesel cars by up to 22%. The effect will be slightly more significant for diesel cars, even though they emit less Co2 (-56 g/km for diesel vs. -53 g/km for petrol).
• Also, preheating almost eliminates emissions of HC and CO.

All in all, the test shows that electrical preheating can reduce the total amount of harmful emissions by up to 71% and fuel consumption by up to 24% under the conditions tested.

Massive reductions in emissions are possible:

At the last count performed by Statistics Norway (SSB), there were 2,6 million private cars in Norway. 47,6% of these were diesel cars, 49,7% were petrol cars, and only 2,7% were low or zero-emission cars. Also, there were 450 000 vans and small trucks,  92% of which were diesel-powered. The average age of Norwegian cars was 10,5 years, higher than the average in countries like Greece, Romania and Hungary. As much as 22% of the cars were 15 years old or more. Older cars on average emit more than newer cars.

• See statistics (Norwegian)

However, new cars also emit more than we would like to think. In 2015 the Institute of Transport Economics in Norway released a report titled Emissions from new vehicles – do they keep what they promise?

• See report (Norwegian)

The report reveals that Euro 6 approved diesel cars emit 4 to 20 times as much NOx during city driving than the requirements for the type approval. The report also shows that emissions from these vehicles on average are four times higher than the average for busses and heavy trucks with Euro VI and Euro 6 diesel engines.

These numbers make abundantly clear that more measures have to be taken to reduce the emissions of NOx and NO₂ from private cars. Increased use of electrical preheating would have a tremendous positive impact on air quality and public health in urban areas.