Minimize environmental impact... and save a few €: Efficient driving

The most effective way to minimize the environmental impact of driving is to leave the car parked. Without being so drastic, efficient driving also helps to save money and reduce environmental impact.

The confinement due to SARS-CoV 2 or COVID-19, as well as the reduction in road traffic during the Filomena Storm, highlighted the indisputable role of traffic with respect to air pollution. He disappeared to the beret above Madrid. The DGT notes in a July 2020 statement that “the lockdown has allowed a unique experiment to analyze the impact of reduced traffic on air quality in cities”. The impact of the drastic reduction in road traffic, which fell between 75% and 80% during the lockdown, reduced nitrogen dioxide (NO2) concentrations in the two largest and most polluted cities in Spain by 62% in Madrid and 50% in the case of Barcelona (https://revista.dgt.es/es/noticias/nacional/2020/07JULIO/0713-Estudio-contaminacion-COVID-19.shtml)

It is obvious that this reduction in NO2 can also be extrapolated to other pollutants. Some emissions caused by the combustion of fossil fuels, used by vehicle internal combustion engines, contain significant amounts of compounds such as carbon monoxide (CO), carbon dioxide (CO2), volatile organic compounds and particulate matter 2.5 (PM 2.5: particles suspended in the air with a diameter of less than 2.5 microns) and other relevant diameters.

However, today, our society, our lifestyle, and the functioning of the economy are unthinkable today without the use of motor vehicles. On the other hand, there are local, national and international commitments to carry out decisive measures to try to mitigate global overheating and achieve carbon neutrality, by the year 2050. In addition, at COP 26, held between October 31 and November 12, 2021 in Glasgow, the Zero Carbon mobility movement emerged until 2035. Spain is also committed, for example, to measures defined in the Climate Change Act (“... adoption of measures to promote sustainability in the transport of goods and travel to work”).

However, are there ways to reduce pollution while we can't do without road traffic?

Yes! Reducing consumption through efficient driving. This measure is also one of the many objectives within the framework of the measures included in the National Program for the Control of Atmospheric Pollution (https://www.miteco.gob.es/es/calidad-y-evaluacion-ambiental/temas/atmosfera-y-calidad-del-aire/emisiones/pol-med/informes.aspx).

Efficient driving

Transport is the sector that consumes the most energy in Spain, accounting for 40% of the national total. It should be noted that passenger cars alone represent approximately 15% of all final energy consumed in Spain, according to the Institute for Diversification and Energy Saving (IDEA) (https://www.idae.es/tecnologias/eficiencia-energetica/transporte)

As the transport sector is very large and includes several modes of transport, we dedicate this Post mainly to cars, since they represent the majority of vehicles on our roads. According to the DGT, of the 34,765,203 motor vehicles registered in Spain in 2020, 24,716,898 are passenger cars.

Car engines are becoming more efficient, and emissions per kilometer have been reduced in recent years. However, up to 80% of a car's greenhouse gas emissions are directly linked to consumption (Umweltbundesamt-German Federal Environment Agency). And it is in this consumption, where the way you drive greatly influences a reduction in emissions and, as a result, pollution. The attitude of drivers and their driving style has a great influence on fuel consumption and is decisive in reducing fuel consumption. But what is efficient driving?

Efficient driving, sometimes called green driving, is a responsible way of driving that aims to reduce fuel consumption, and can contribute to an average reduction of 15% (even up to 25% according to the DGT).

At Ideas MedioAmbiental we were able to verify in practice the effectiveness of driving in different ways. Two colleagues, in the same project, with the same type of vehicle, with the same equipment and with the same type of tires, were traveling a mountainous region of León, along the same tracks, with the same unevenness and with some comparable long road trips to return to their place of residence. Let's look at the specific case: during the project, the average consumption control was 6.1 l/100km in one of the two vehicles, and 6.7 l/km in the other, a consumption greater than 9.84%.

Reducing costs and CO2:

Taking the mileage data from the first vehicle, the following results are arrived at:

Kilometers traveled per month: approx. 2,930 km

2,930 km/100km x 6.7 l = 196.31 l refilled

2,930 km/100km x 6.1 l = 178.73 l refilled

Difference 17.58 l/month x 1.80 Euros/l = 31.64 Euros x 12 months = 379.73 Euros/a saved per vehicle

As can be seen, the advantages of efficient driving translate into significant savings, including lower vehicle maintenance costs (engine, brakes, gearbox, tires...).

Other objectives related to efficient driving, in addition to economic savings, consist of environmental benefits, such as the reduction of environmental pollution by reducing emissions of CO2 and other substances harmful to the environment and to health.

It may seem little, but what happens if efficient driving were applied to an entire country like Spain and fuel consumption in the traffic sector was reduced by 10%? What if we reduce the CO2 emissions of just over 58 million tons emitted by the transport sector by 10% over a year like in 2020? Taking these figures into account, 10% less is a significant reduction.

How to reduce consumption, and save money

Here are some tips for efficient driving, divided into two blocks (while driving and additional tips):

1. If your model has Eco mode, turn it on

i. Eco mode is a function to optimize fuel consumption and acts on certain driving actions (de-/acceleration, speed changes,...) and on some vehicle systems (e.g. heating and air conditioning)

2. Turn off the engine during long shutdowns

a. If your model has the Stop and Start function, activate it

i. The savings from activating the Stop and Start system can be between 4 and 8.7%.

b. If the vehicle does not have the Stop and Start function, it is recommended to turn off the engine during parking for longer than 20-30 seconds.

i. After about 30 seconds, an engine idling has already produced more pollutants than when starting it, especially when the engine has already reached the optimum operating temperature.

ii. Modern engines have an average lifespan of 200,000 starts, meaning that with an average start per kilometer, 200,000 kilometers can be covered.

iii. Some sources talk about turning off the engine for up to 7 seconds (see video: Savings by Stop and Start).

iv. The consumption of an engine running at idle can consume up to 1.5l/hour depending on the model. 3 minutes at idle speed can be equivalent to the consumption of one kilometer at 50km/h.

c. Apart from reducing consumption, it helps to reduce noise, which is of special interest in urban environments.

3. On 4×4 models, activate 4-wheel drive only when necessary

a. Set 2-wheel drive (WD), not Automatic or 4×4 when not using the 4×4.

i. On some models equipped with a 4×4 transmission such as the Duster 4×4, the manufacturer recommends starting second on horizontal ground, with the vehicle empty.

4. Bootstrap

a. Start the engine without stepping on the accelerator.

b. Diesel engines may need to be lubricated for a few moments, but only a few seconds, so the process would be to start the engine, put on the belt and start the exit.

c. Start running immediately after starting on gasoline engines.

5. Gear change

a. Modern vehicles indicate the ideal time to change gears. Follow the Speed Change Indicator indicator light on the instrument panel.

b. It drives in the longest possible speed and at low revolutions.

c. Keep your driving speed as uniform as possible, avoid sudden accelerations and braking.

d. Brake as little as possible - as long as circumstances permit -, taking advantage of the vehicle's own inertia (“engine brake”) with the gear engaged when you have to slow down (and if possible without downshifting).

and. It accelerates progressively, without pressing the pedal thoroughly and changes gears between 1,300-2,000 revolutions in diesel engines, between 1,500-2,500 revolutions in gasoline engines respectively.

i. This means, for example, with a Duster Diesel version, which can already be driven on many occasions in 5th gear exceeding 50km/h, in 6th gear with 60km/h. In gasoline engines, depending on the models, it may be equivalent.

ii. Acceleration and noise: a single car at 4,000 rpm causes the same noise as 32 cars at 2,000 rpm!

f. You can jump gears, accelerating a little more thoroughly before changing them, for example, from 3 to 5 or 4 to 6., depending on the circumstances (driving on a flat plane,...)

i. Every time you change the gear, you lose speed and you have to recover it, and skipping gears avoids those energy losses to be recovered later (figure 2).

g. When decelerating, it is advisable to change gears as late as possible (just over 1,000 rpm approx.).

h. On descents, you should never go down with the engine in neutral, of course for safety reasons, but there is also fuel consumption, while engine braking does not involve any consumption.

Fig. 2: Consumption as a function of speed for different gears Source: Institute for Diversification and Energy Saving. Efficient Driving Manual for State Fleet Drivers, page 10 (IDEA, 2002)
6. Anticipation, Forecasting and Deceleration

a. Keep the safety distance to anticipate unforeseen events and ensure an adequate field of vision.

b. When decelerating, lift your foot off the accelerator and let the vehicle roll with the gear engaged. The motor will act as a brake and consumption will be zero. The wheels, instead of receiving torque from the engine, drag the engine in its rotational motion and the injection will be zero.

c. Observe possible obstacles, traffic lights, curves,... well in advance, and often it will be enough to lift your foot and take advantage of the inertia of the engine (zero consumption) instead of braking.

i. Remember: In urban traffic, it's not the fastest person who goes the fastest, but the one who stops the least!

7. On the road, get used to a relaxed driving style

a. and if possible at speeds such as 100 km/h on motorways.

i. An increase in speed by 20%, for example, from 100 to 120 km/h, can mean an increase of 44% in consumption depending on the engine model and external circumstances such as wind... (consumption depends on the speed raised squared).

8. Electricity is expensive

a. Heating, thermal windows, charging electronic devices,... and above all air conditioning increase consumption by up to 25%.

9. Airconditioning

a. It is advisable to keep the indoor temperature around 23-24ºC, not colder, but not hotter.

i. Air conditioning (A/C) can considerably increase consumption (depending on the vehicle model and the type of use between 0.2/0.3 - 1.5 l/100km according to sources consulted)

b. Often the question may arise which is better: driving with the windows down or with the A/C on, since driving with the windows open increases resistance to movement and extra consumption can reach 4-5%.

i. General rule: On short trips, or at low speeds, it may be advantageous to drive with the windows open or with the windows raised and the aerators open before setting the A/C. Starting at 70-90km/h as a general rule, it will be more advantageous to turn on the air conditioner

ii. In circumstances of high air pollution, or during a high pollen load if you are allergic, you have to consider what is most convenient, since it may be inadvisable to drive with the windows open under these circumstances.

c. Never use the air conditioner with the windows down.

d. If the vehicle was parked in full sun, open the doors for a few minutes to ventilate the interior before starting

i. It is an important difference for the cooling system to have to cool the interior of the vehicle by 45ºC or 25ºC.

Other recommendations:

1. Read the manufacturer's manual carefully, with advice on environmental aspects and advice for maintenance and economic use.

2. Good vehicle maintenance contributes to its optimal functioning; and not only is it essential for vehicle safety, it also extends the life of the vehicle and can reduce consumption and pollution.

3. It circulates with the right pressure state of the tires, which at the same time perform less friction with the asphalt and therefore save fuel. Incorrect tire pressure, in addition to being a safety risk, causes the vehicle to offer greater rolling resistance, increasing fuel consumption by up to 10% and shortening the lifespan of tires due to increased wear and tear.

4. Use long-lasting tires and choose suitable tires according to the time of year (winter, 4 seasons,...) and check their good condition, which is very important for road safety.

5. In winter: The engine never heats up when the vehicle is stopped, the engine heats up efficiently while driving smoothly until it reaches the right temperature, so cleaning ice crystals is NOT done while the engine is running.

i. A cold engine for a mid-range passenger car can consume up to 30l/100km directly after starting and will reach its average consumption after it has reached its optimum operating temperature.

• • • Following this argument is the reason, so short routes should be avoided as much as possible. Avoiding them can save fuel and protect the engine, and there are often alternatives (on foot, by bike, public transport, personal mobility vehicles (VMP's))

ii. In addition, it is advisable to travel about two kilometers before turning on the heater, when the engine has warmed up and can take advantage of the waste heat. On the contrary, when the heater is turned on when starting, the engine injects more fuel to be able to supply heat to the heater. (In no case forget the safety - for example - that the windows are fogged up).

6. Weight and luggage rack

Avoid overloading the vehicle caused by excess weight and objects

a. Reduction of load weight.

i. The vehicle is not the place to store and store objects and every 100kg of additional weight can increase consumption by up to 0.3l/100km, depending on several parameters it can be even higher.

b. Remove the luggage rack if not in use (reduced aerodynamic resistance).

i. Adding both points together, the extra weight and roof racks can increase consumption by up to 40%.

7. Avoid filling to the brim, especially at high temperatures, since due to aspects of expansion of the fuel, evaporation of the fuel can be caused, losing that amount of fuel, in addition to not contributing to local air pollution due to said evaporation. Also to avoid overflow.

8. Replenished from time to time with high-end fuels, especially before long road trips. In this case, it is not primarily a matter of economic savings, although more kilometers can be made per tank. Above all, it serves primarily for good engine maintenance, since due to its higher level of refinement, they increase engine performance and protect it.

9. Plan your route and check the traffic status to avoid traffic jams. A navigator on unknown routes will save you from unnecessary twists and turns.

10. Sign up for an efficient driving course at a driving school in your city or neighborhood.

11. Check fuel consumption periodically to detect possible vehicle faults.

12. Finally, the best way to save fuel and money is to leave the vehicle parked and use alternative means of transport, car sharing or bicycle use, also for work purposes. In addition, on intra-urban journeys, it is important to consider door-to-door time, and this is where the bicycle is faster than a car up to 5 kilometers, the VMP even up to about 8 kilometers.

Conclusion:

There are many possibilities to reduce fuel consumption through driving style, but it all starts with mentalizing and constantly reviewing your personal way of driving. Achieving the reduction means changing habits little by little, so that in the end they are intrinsic habits. Check your driving style and activate Instant Fuel Consumption, which will help you visualize your consumption. But remember:

All tips for efficient driving are used as long as circumstances permit, so that safety is not affected.

Efficient driving never prevails over personal and road safety!

Fonts used:

— https://revista.dgt.es/es/educacion-formacion/conducir-mejor/2017/0213-Conduccion-eficiente-diez-claves-para-consumir-menos.shtml

— https://coches.idae.es/estilo-de-conduccion (IDEA: Institute for Diversification and Energy Savings)

— https://www.idae.es/uploads/documentos/documentos_manualPME_6bc54e20.pdf (2002)

— https://www.cea-online.es/blog/139-las-10-claves-de-la-conduccion-eficiente (CEA: European Motorists Club)

— https://www.umweltbundesamt.de/umwelttipps-fuer-den-alltag/mobilitaet/sprit-sparen (German Federal Environment Agency)

— https://www.adac.de/verkehr/tanken-kraftstoff-antrieb/tipps-zum-tanken/sprit-sparen-tipps/ (Automobile Club of Germany, equivalent to the Real Automobile Club of Spain (RACE))

— User manual (Dacia Duster)

— https://www.tuev-nord.de/de/privatkunden/ratgeber-und-tipps/sparen/sprit-sparen/sparsam-fahren/ (TÜV Nord: Northern Vehicle Technical Inspection)

— https://www.seas.es/blog/energias_renovables/principales-elementos-contaminantes-de-los-vehiculos/

— https://www.youtube.com/watch?v=i9_mPgl9cnI (Savings by Stop and Start)