How does cylinder deactivation work? It is a fuel management system that allows the engine to run on fewer cylinders, reducing fuel consumption and emissions while maintaining adequate power and performance.
The system temporarily shuts down some of the engine’s cylinders when they are not needed.
I saw it first in my uncle’s car about 20 years ago. I asked which button it was, and he explained how cylinder deactivation works, which I will share with you below.
Click here to read another article on engine cylinders.
Keep reading below for more details.
What Is The Principle Behind Cylinder Deactivation
A 6-cylinder engine is a massive engine in a car. Sometimes the car can work with a lesser cylinder to perform some particular duty. The car can still work when all the cylinders are not used; this idea is called deactivation.
When all cylinders of the engine are required, when the vehicle is accelerating, towing, and tedious works, all the cylinders must work properly. But when the car is cruising, with only light loads, shutting down a few cylinders will increase fuel economy. Not that the difference is vast.
Shutting down half the cylinders certainly doesn’t double or nearly double gas mileage. However, with higher and higher gasoline prices, the improvement in this step is enough to make a considerable difference in overall running costs.
However, 2 or 4 cylinders can sometimes be shut down, leaving 4 or 6 cylinders working. An innovative variable displacement (also known as “modular displacement”) engine developed by Eaton was standard on all 1981 Cadillacs.
This basic principle is not new; experiments were carried out during World War II. In GM’s version, a microprocessor decides which cylinders can be omitted at a given moment.
As usual, the valve lifters and their associated pushrods move up and down the engine, but those unneeded valve pairs still spin.
With 4 cylinders running, the displacement returns to all 8 as soon as the driver depresses the accelerator pedal for overtaking or merging.
This response is meant to reassure drivers who doubt the power of the 4-cylinder Cadillac. Not that they can expect a vigorous response.
A solenoid controlled by the ECM is moved to disengage the desired cylinder’s rocker arms from their respective pushrods to deactivate a cylinder.
When cylinders are deactivated, the ECM reduces the amount of fuel injected, but the system can’t cut off fuel to specific cylinders.
What Are The Disadvantages Of Cylinder Deactivation
One disadvantage of cylinder deactivation is the resulting reduced performance. Anyone who is used to driving with a six or eight-cylinder engine and prefers a sporty driving style will feel the loss of power.
It caused significant vibrations without a substantial improvement in efficiency.
One very important criterion for cylinder deactivation remains: the driver must not notice anything about it.
That is, of course, more complex to implement with a four-cylinder. To prevent imbalance in the engine, some engines use balancer shafts, which makes the engine heavier and the entire construction more expensive.
If these additional costs are not offset by reduced fuel consumption, series production is anything but sensible.
When cylinders are deactivated, there may be a risk that the effort is not in reasonable proportion to the benefit. Cylinder deactivation can also become a problem in diesel engines with four or fewer cylinders and high torque, namely, precisely in the situation when smooth running is lost when a cylinder is switched off.
That would then have to be compensated for with a higher speed, which directly results in higher consumption.
What Is The Advantages Of Cylinder Deactivation
Cylinder deactivation offers several advantages. Firstly, it reduces fuel consumption by reducing the number of cylinders actively burning fuel, resulting in better fuel economy, especially during low-demand driving situations.
Secondly, cylinder deactivation helps reduce emissions by optimizing the combustion process.
With fewer cylinders running, the engine can achieve a more efficient air-fuel mixture, The engine may produce a more efficient air-fuel mixture with fewer cylinders working, which reduces the amount of pollutants emitted into the atmosphere.
Additionally, cylinder deactivation improves vehicle dynamics by reducing overall weight and friction within the engine.
Driving becomes more pleasurable as a result of the increased torque, power, and throttle responsiveness.
How Much Gas Does Cylinder Deactivation Save
To decrease polluting emissions and increase the energy efficiency of internal combustion engines, automakers are always developing new technology.
One of these systems is the disconnection of engine cylinders, a technology that promises to offer fuel consumption savings of up to 20% by deactivating half or part of the mechanical cylinders.
The savings might reach up to thirty percent, depending on the type of car and driving behavior.
That is, cylinder disconnection is designed for situations in which the full power of the engine is not required, such as, for example, when driving on a flat road at a not very high pace or when we do not require significant acceleration capacity.
The activation and deactivation process is carried out much faster than it takes you to blink, so behind the wheel, it is very difficult to notice the process.
What Is The Mechanism Of Cylinder Deactivation
It continuously keeps an eye on a number of variables, including engine load, throttle position, and vehicle speed, to figure out how many cylinders to deactivate.
For seamless functioning when switching between on and off cylinders, the ECM regulates the opening and closing of fuel valves and injectors.
A solenoid mechanism is used in the distribution that prevents the exhaust and intake valves of the cylinders that you want to deactivate from opening, in which combustion does not occur.
However, there are also some cases in which the fuel injection in those cylinders has been deactivated, but they are the least (the 6.5-liter V12 engine of the Volkswagen group, for example).
What Companies Use Cylinder Deactivation
Cylinder deactivation is not a new technology since, contrary to what you might think, it has existed for decades: it began to be experimented with in World War II.
General Motors carried out the first application of this system in the automotive world with the support of Eaton Corporation, which in 1979 presented the V8-6-4 engine.
This 6.4 V8 block was capable of operating with eight, six, or four cylinders and was mounted, for example, on the 1971 Cadillac range.
Cylinder deactivation is increasingly widespread among brands. It is currently found in models from companies such as Audi, Alfa Romeo, Porsche, Mercedes, and Ford and in cars ranging from simple utility vehicles to impressive sports cars.
Does Honda Have Cylinder Deactivation
The answer is yes. Honda has cars with cylinder deactivation. For example is the Honda Accord, which uses a variable displacement system, which is Variable Cylinder Management.
This system allows the engine to deactivate the cylinders when cruising at a constant speed, resulting in greater fuel efficiency.
Automakers can lower emissions while increasing the general performance and efficiency of their cars by implementing cylinder deactivation technology.
This cutting-edge powertrain technology contributes to a more ecologically friendly and sustainable automotive industry by demonstrating the ongoing advancements in engine design and control systems.
What Is Cylinder Deactivation Called
Another name for cylinder deactivation is Active Fuel Management (AFM).
AFM was designed to provide maximum fuel economy under light-load driving conditions by deactivating the lifters on specific cylinders.
In V8 vehicles, half of the cylinders are deactivated, and in V6 engines, two of the cylinders are deactivated.
Under certain operating conditions, the Engine Control Module (ECM) directs the cylinder deactivation system to deactivate engine cylinders 1, 7, 6, and 4 on V8 engines or 3 and 6 on a V6 engine.
The engine will operate on all cylinders during engine cranking, engine idling, and medium to heavy throttle applications.
Does Cylinder Deactivation Hurt Engines
The answer is no. If you are one of those who think that the less technology an engine has, the better it is to reduce the risk of possible breakdowns, and you have set your sights on a car equipped with cylinder disconnection, you can rest assured.
There are many cars with these systems working, which have traveled millions of kilometers in all types of situations, and there are no known failures or problems related to their operation.
Although there are few complaints about cylinder deactivation, they are minimal. If you compare and contrast the positive and negative aspects of cylinder deactivation, the positives supersede the negatives.
You can read about the few negative aspects of cylinder deactivation under the subheading “WHAT ARE THE DISADVANTAGES OF CYLINDER DEACTIVATION?”
Conclusion
Cylinder deactivation is a fuel management system in which some cylinders are turned off when not needed to reduce fuel consumption and emission rates.
Remember that there are some cons, such as vibration against the cylinder deactivation, although with technological advancement, such a problem has been care for.
With cylinder deactivation, you can save between 20-30% of the consumption, which is one of the major advantages of cylinder deactivation.
Many car manufacturers used cylinder deactivation in production such as Honda, Audi, Mercedes, and other sporty cars.
Click here to read another article on fuel economy.