Nowadays, every car manufacturer uses turbocharged engines in their cars. It is actually uncommon to find a car without a turbocharger; only the smallest of engines might not have one. So where has this trend come from?
Cars have become better
It is commonly known that the latest cars have better fuel economy than their predecessors. There are several reasons for this. Cars have become more aerodynamic, thus less resistance needs to be overcome, and automatic gearboxes with many gears make sure the car operates at its most efficient point as much as possible. However, perhaps the greatest gain has come from engine development itself.
As a customer, you want a car that can accelerate adequately and is very fuel efficient when driven at speed. A naturally aspirated engine can generally do only one of these, so as a turbocharger manufacturer we have to help car and engine manufacturers achieve both goals at the same time.
The principle of power
Without going into too much detail, the principle of making power with a petrol engine is as follows: a certain amount of air is sucked into the engine and fuel is injected at the optimal ratio to create a combustible mix. Logically, the bigger the volume of the combustible mix the more power you are able to generate. A downside, though, is that if you do not really need it, you still burn a high amount of fuel. If you downsized the engine to reduce this, you simply end up with an engine that produces less power. Therefore, a device is needed that can force extra air into the engine to create power when required, yet ensures the small engine is still fuel efficient when extra power is not needed. This is exactly what a turbocharger does: it provides extra air to the engine to create power.
How can you as a driver optimize the fuel economy of the car?
Firstly, let us clear up a common misconception right away. A turbocharged engine does not become magically more fuel efficient without you as a driver using it sensibly. If you are braking and accelerating erratically, you will never achieve good fuel economy.
Lower speeds, constant speeds
The first and most obvious thing you can do is to drive at lower speeds. Leave your house five minutes earlier and drive at 100 km/h instead of 120 km/h. If you have an average commuting distance of 70 km, this lower speed will only increase your travel time by seven minutes, so the delay is minimal (another nice side effect is that you will arrive more rested because you have not driven with your usual urgency). When driving at lower speeds, try to maintain consistency (cruise control is the perfect aid here). Hovering around 100 km/h manually will not give you the same fuel economy as doing 100 km/h on cruise control. Almost every car sold has cruise control, but if your car doesn’t you can probably have it retrofitted.
It is well-known that a turbocharged engine has great torque output at lower engine speeds, so don’t overdo it and shift early to a higher gear (a nice guideline is 2000 RPM). The higher the engine speed, the higher the fuel consumption – and the time you gain by accelerating in a lower gear is negligible.
Anticipate traffic, lift and coast
Probably the hardest thing to do or learn, but it can also save you some fuel if done properly. Instead of driving on cruise control and braking for a traffic light or junction at the last possible moment, coast for some distance and let the engine slow the car down a bit by lifting off the accelerator. When you don’t apply throttle, the engine doesn’t use any fuel and instead is helping to slow the car. Please don’t change to neutral and coast this way because the engine will still be using fuel, which is ineffective.
Much overlooked by the majority of the people, but tyre pressure also has an impact on fuel economy. If the pressure is too low, the tyre is relatively deformed under load. When driving, this constant deformation creates a friction/drag that the engine needs to overcome, thus increasing fuel consumption. The correct pressure for your tyres can be found inside the car, usually by the driver door area, or by the petrol cap. You can go a little bit higher than the recommended pressure, but not too much or you will be spending your money on buying new tyres.
Use a proper quality of fuel
Fuel standards are much higher than they were 20-30 years ago, but it does not hurt to top up the tank with a proper quality of fuel. Although it might cost you €3-5 more for a full tank, it is definitely worth it. Modern engines are equipped with all kinds of sensors, and with a higher quality fuel the combustion can be timed more “critically” before the petrol knocks (the uncontrolled combustion of fuel when it is not needed). This timing extracts the maximum amount of energy out of each drop of petrol, meaning you need less fuel to get the same power as you would get from a lower quality of fuel. You can recognize the quality of fuel by its RON number. This number should be shown on every pump at the petrol station. If not, an employee will be able to tell you. The higher the RON number, the higher the resistance against knocking. Combine this with the fuel economy optimization techniques mentioned earlier and it is very likely you will be better off financially than when you were buying the cheap fuel and driving however you pleased.
How to keep your engine/turbocharger as healthy as possible
Besides looking at the techniques for optimizing fuel economy, how can you keep your engine and turbocharger in good condition for as long as possible?
Start and end your drive slowly
Although car and turbocharger manufacturers consider many scenarios about how customers might use their car – and test thoroughly to make sure components keep functioning as they are intended – it doesn’t hurt to think with the component rather than against it. For example, no one fancies going for a run 10 seconds after waking up, and then going straight back to bed when you’ve finished. Likewise, engines and turbochargers like to be eased into performing. That means easing into the drive and doing the same for the last 5 km or so as well. As your engine and all its components work in harsh conditions, “warming up” and “cooling” – just as you would before and after exercising – takes the edge off the stress the components go through.
Another logical step you can take is to regularly service the car by refreshing the oil and all the filters. These degrade over time and if used for too long without being replaced, wear and damage will accumulate.
To sum up, by following the steps of driving at lower speeds, anticipating traffic, keeping your car well maintained and more, you will be well on your way to reduce the fuel consumption of your turbocharged car.