Most diesel engines come with a turbocharger to increase the torque of the engine and delivers air to sustain efficient combustion at a much higher fuel flow.
The turbocharger gets its power from the heat energy of the exhaust gases, which is the opposite of a supercharger that is belt driven and uses more energy than what it actually delivers at lower RPM.
According to the experts, instead of just being blown into the open atmosphere from the exhaust, the hot exhaust gases are channeled to drive a turbine wheel in the turbo exhaust housing.
High RPM does not drive the turbine, but the expansion of the gases once they are cooled down does.
These days, modern turbochargers that are fitted to ECU-controlled diesel engines control boost pressure, either by vacuum control or an electric motor known as a Stepper Motor bolted to the side of the turbo.
The role of a turbocharger is to turn waste exhaust gases into energy, and in doing so, it not only increases fuel efficiency, but it also reduces exhaust emissions, making it the most effective and economical method for making an internal combustion engine more energy efficient.
There is a constant debate in the 4×4 world and automotive industry regarding whether or not diesel engines are in fact stronger and more reliable than petrol engines. To understand why diesel engines last longer than petrol counterparts, click here.
What is an intercooler?
An intercooler is a component that cools the intake air on engines that are fitted with forced induction (turbocharger or a supercharger) system. It cools down the air after it has been compressed by the turbo or supercharger before it enters the engine itself.
But what is the role of the intercooler?
An intercooler is fitted between the turbocharger outlet and the engine intake manifold, to reduce intake air temperatures. This allows for a higher boost and fuel load setting while retaining moderate combustion temperatures that are essential for engine longevity.
How does an intercooler work?
Turbochargers compress air and increase its density before reaching the cylinders of the motor. The more air each cylinder gets, the more fuel the engine is able to burn, therefore pushing out more power.
The entire compressing process creates so much heat, also increasing the temperature of the air entering the motor. As the air becomes hotter, it becomes less dense, reducing the amount of oxygen that is in each cylinder, and also impacts the performance.
This is where the intercooler comes in. Intercoolers cool the compressed air and provide the motor with more oxygen, improving the combustion in each cylinder. It also increases the reliability of the motor as it regulates the temperature of the air. Intercoolers also ensure that the air to fuel ratio in each cylinder is safely maintained.
There are two types of intercoolers
Air-to-Air
An air-to-air intercooler passes compressed air through small tubes. The heat is transferred from hot air into cooling fins, which are always kept cool via air from the outside moving vehicle. Once the cooled compressed air passes through the intercooler, it’s fed to the intake manifold of the motor and from there, into the cylinders.
These types of intercoolers are lightweight and cheap, making them the most popular choice for most turbocharged motors.
Air-to-water
Air-to-water intercoolers use water to lose the temperature of the compressed hot air. The cool water is pumped via a unit that extracts the heat from the air as it passes through the unit. Once the water is heated up, it is pumped through the radiator or cooling circuit before it re-enters the intercooler.
They are much smaller than air-to-air intercoolers. They are much more suitable for engines as water conducts heat better than air does. However, its cost and weight are why they are not found on vehicle motors.
Where are intercoolers placed?
Air-to-air intercoolers can be found anywhere between the turbo and the motor. They operate better where the airflow is at its best and are usually situated at the front of the vehicle, behind the grille. For some vehicles, the motor layout prevents it, and the intercooler is placed on top of the motor. The airflow is less here and the heat from the motor may impact the intercooler over time, this is why ducts and scoops in the bonnet are added to improve the airflow
Where’s the Air?
When purchasing a turbodiesel intercooler, always bear in mind where the air outlets are placed on it because they indicate how efficient the intercooler will perform. Although some turbo diesel intercoolers are shaped for a clear, smooth flow, it all boils down to how accurately the air flows and how quickly the air cools down are the main issues to take into consideration.
