Thursday, 20 January, 2022

Eco-driving: 10 tips to reduce your fuel consumption


Each of his visits to a gas station is a pain for the motorist. However, if we are to believe the statistics of the INSEE, the volume of fuel that a French can afford with an hour of minimum wage has continued to increase over the past fifty years: it would even have doubled between 1973 and 2018. For their part, technical progress does more than compensate for the weight gain of our vehicles. The reduced appetite of modern engines explains why the fuel item barely weighs more on the budget of families who nevertheless cover nearly twice as many kilometers as at the beginning of the 1970s.

These figures should help motorists to put into perspective the impact of rising fuel prices on their purchasing power. To preserve it more, they can decide to act on their driving habits. The recipes for eco-driving are far more effective at reducing an engine’s appetite than any of those uneconomic “fuel savers”. Let it be said, real savings come at the cost of serious self-discipline!

Rule N ° 1: shut off the engine during a prolonged shutdown

This recommendation makes sense. Yet it comes up against a belief as old as it is outdated: restarting an engine after a brief stop would burn more fuel than it consumes for a minute. This assertion lost all validity with the generalization in the early 1990s of the electronic fuel injection system on gasoline engines. Because it operates with excess air, the Diesel engine is even less likely to overconsume when restarted.

However, too many motorists prefer to leave their engine running when they queue at a gas station or at an American restaurant. An implacable factor favors this practice: the generalization of air conditioning. Just look at the number of cars that park with their engines running during the lunch break. Summer and winter alike, artisans and business travelers take refuge there to enjoy their sandwiches away from the heat of the sun or the bite of the cold. All the more readily since, very often, it is their employer who pays for their fuel.

Rule N ° 2: leave the Start & Stop to act, automatic stop-start system

This system annoys more than one (because of the jolts it generates) but it has the potential to save nearly half a liter per hundred kilometers on a vehicle that travels most of the time in town. To meditate.

The computer controls the switching off of the ignition (or the stopping of the diesel supply pump on a Diesel) as soon as the vehicle speed falls below 5 km / h. It is also necessary to place the gear lever in neutral and release the clutch pedal. Note that these automatic stop-start systems are becoming more and more discreet over the generations.

Disadvantage, the automatic stop-start function involves the fitting by the manufacturer of a reinforced battery, heavier and appreciably more expensive. To avoid a nasty surprise, the motorist will do well to invest in a trickle charger capable of extending the battery life expectancy. His secret? A succession of low intensity pulses drops the sulphate which aggregates on the lead plates and starts the charging capacity.

Rule N ° 3: in the morning, I do not heat the mill!

In the series of misconceptions that should be twisted, now let’s move on to this bad habit of letting the engine warm up at idle. It’s bad for the planet and bad for your wallet!

This practice, inherited from the heroic days of the automobile, was aimed at preventing engine wear, which occurs at start-up, when the oil has not reached its full fluidity. Warming up the engine consisted of waiting for the oil to warm up before setting off. The very operation of the engine was facilitated by the heating of the air-fuel mixture admitted into the carburettor (less jerks and dips when restarting). These precautions are no longer useful on injection engines, protected by modern oils offering much better cold protection than forty years ago.

Our advice: as soon as the engine is running, engage the clutch and drive off slowly. Moderate your pace and diet for the first 4-5 minutes. At the same time, you will heat up the gear oil, which can sometimes be hard to handle on winter mornings.

Rule N ° 4: ride lightly and anticipate slowdowns

Learning to moderate the ardor of the foot on the right pedal is undoubtedly the most difficult teaching of eco-driving, otherwise called reasoned driving. Because it is a question of seeing the absurdity of accelerating briskly when the light turns green to arrive too quickly at the next red light and throw yourself on the brake pedal the next moment. . Inept.

Some well-inspired cities had erected in the 1990s variable message signs indicating the speed to be respected to benefit from what was called “the green wave”. By driving at 39 km / h for example rather than 50 km / h, motorists were more or less guaranteed to keep the green lights going.

Anticipating slowdowns and adopting less nervous driving has the potential to reduce your fuel consumption by a quarter in the city. Resist the temptation to slow down at the last moment. Play on your momentum to come and die on the fire line: you will even save on brake pads!

The engine brake saves fuel. Remember that consumption is zero as soon as the driver completely takes his foot off the accelerator … provided that a gear is kept engaged! Otherwise, the engine is no longer driven and its rotation speed drops to idle. Which must be maintained by injecting a little fuel.

Rule N ° 5: moderate your speed on the motorway

It remains to be seen whether lowering the maximum permitted speed on secondary roads to 80 km / h will have a beneficial effect on the appetite of all types of vehicles. On the other hand, the economy is indisputable on the motorway, due to the exponential increase with the speed of the air resistance when moving forward. Stick to the regulatory 130 on the highway and your range on a full tank will increase significantly. The effect will be even more noticeable if you let the speed drop on a hill. The loss of time is negligible: it is measured more in terms of frustration than in minutes.

Rule N ° 6: use cruise control!

Besides the comfort it offers on long stages for the right leg, cruise control helps to save a little fuel. This system maintains the predefined speed both uphill and downhill. What it over-consumes in the first case, it largely recovers downhill and on the flat. Because the action of the driver on the accelerator is almost always more jerky. Besides, he doesn’t always have his eye on the speedometer.

Rule N ° 7: play on the torque and flexibility of the engine

Another bad habit: rather than letting his vehicle gradually increase its speed in the upper gear, the motorist prefers to downshift and crush the accelerator to enjoy good times. To save a little fuel, it is preferable to exploit the flexibility of the engine (its torque, expressed in Newton-meter, abbreviated Nm).

As great followers of Diesel, the French have learned to appreciate the superior torque offered by this type of mechanics compared to gasoline, at the same displacement. At low revs, the pickups on a Diesel are sufficient to stay afloat and manage unevenness. In addition, the torque in first gear and reverse gear allows you to drive in a parking lot and maneuver without touching the accelerator. Sometimes even on a slope!

In town, the torque of the engine motor very frequently allows fifth gear to be shifted to 50 km / h on the flat. In this regard, the indicator light in the shape of an arrow which indicates the opportune moment to change gear (“Shift Indicator Light”, in English) constitutes a precious ally in your learning. A fanatic practitioner of eco-driving will want to follow the indications of this clairvoyant to the letter. But a good driver must know how to look far: there is no point in shifting upshift if he sees a steep slope, for example.

Rule N ° 8: very soft, with air conditioning!

The overconsumption induced by the air conditioning compressor drive is generally evaluated at one liter of gasoline per hundred kilometers. It is for this same reason that manufacturers are adopting en masse electric power steering, replacing the hydraulic pump driven by the engine and wasting a few horsepower.

Common sense must prevail. If the profiling of modern cars makes it painful to drive with the window down due to the beating of the air, it is possible to be satisfied in the spring with simple ventilation, without activating the air conditioner. In warmer weather, do not set the air conditioning 4 degrees cooler than outside. Otherwise, you overuse and you risk headaches, itchy throat and runny nose.

Rule N ° 9: tires properly inflated and engine overhauled

Same explanation as before. Tires maintained at the recommended pressure limit both rolling resistance and wear. In this vein, do not hesitate to over-inflate each envelope by 0.2 bar, even when you are not riding under load. In addition, it is recommended to prefer so-called “eco” tires, offering the lowest rolling resistance.

Have the spark plugs and the air filter changed regularly. According to ADEME, if it is clogged, your vehicle’s engine consumes 3% more fuel. The same goes for the injection system, to have it checked when cold starts become difficult and times become difficult.

Rule N ° 10: prefer the trailer to the roof box

This is the great classic of anti-overconsumption measures, taught in all driving schools: roof racks, ski racks, roof boxes and open windows induce resistance to forward movement which leads to additional effort. of the engine, and therefore overconsumption.

Good to know

  • What are E85 ethanol converters worth?
  • Installing an E85 box: the steps to drive on ethanol
  • Driving on hydrogen is possible with French Symbio

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