Afton Chemical presents GDI Video Series featuring Ricardo PLC
Afton commissioned Ricardo PLC, the global engineering, environmental and strategic consultancy to provide insight on existing and emerging gasoline engine hardware trends. In this series of videos - Dr Richard Osborne, Ricardo’s global technical expert for gasoline combustion - and Jon Pilbeam, a senior R&D engineer for Afton, discuss the following trends and the implications they pose to fuel and fuel additives.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Engine Downsizing
Engine downsizing is the use of a smaller engine, which is boosted with a turbocharger, replacing a larger naturally-aspirated engine. Downsized engines operate at higher load to achieve the same vehicle torque and power, reducing throttling losses and the effect of engine friction. This leads directly to improved vehicle fuel economy. As downsizing retains performance whilst reducing the size of the engine, it increases the power density. This means that the engine has to deliver higher power more of the time, leading to more heat being produced. As a result, fuel injectors and combustion chamber are subjected to higher temperatures more often. This places the fuel under higher thermal stress, which leads to a risk of more deposits forming. Fuel additives can play a role in minimizing and preventing deposit formation, protecting the engine.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Spray, Metering and Calibration
The purpose of engine calibration is to ensure that the engine has the right combination of fuel, air and ignition timing to deliver the required vehicle operation. Optimal engine operation improves performance, fuel economy and emissions. Fuel metering means the fuel is delivered and injected into the engine at the right time and in the correct quantity. Controlling combustion precisely allows car manufacturers to meet tougher CO2 and emissions legislation. In these increasingly sophisticated combustion systems, optimised fuel delivery is key. Good quality additized fuel will reduce deposits and restore optimised engine performance. It’s also important to remember, the demands of higher fuel injection pressure also requires gasoline with good lubricity – which is another area where fuel additives can provide measurable benefits.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Mild Hybrids
A mild hybrid can be defined as a powertrain that uses more than one energy source, where the second source of energy supplies less than 20% of the total power. For example, an internal combustion engine and a 48 Volt motor/ generator. In motor mode, it can produce mechanical torque from battery power. In generator mode, the same unit can absorb power from the vehicles’ wheels during braking and convert it into electrical energy to charge the battery. Therefore, there are significant CO2 reductions available. It also means the complexity of the powertrain increases, as well as the overall cost and weight of the car. Because of this, as the mild hybrid market grows, good quality fuel will be essential in minimizing any risks from these rapidly emerging technologies.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Injector Position
In Gasoline Direct Injection engines, the fuel is injected directly into the cylinder from either – the intake side – OR – the centre of the combustion chamber. Original direct injection systems were side mounted. Side mounted injectors are generally located between the inlet valves at the side of the combustion chamber. A central injector position is advantageous in that its downward spray direction reduces the risk of the fuel coming into contact with cylinder walls. In both instances of central or side mounted injectors it is essential to minimise deposits. Good quality fuel with deposit control additives optimises combustion, fuel economy, emissions and performance.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Cylinder Deactivation
Cylinder deactivation is when a number of cylinders are shut off under low-speed and low-load engine conditions. Fewer cylinders are instead run at a higher load to maintain the same power. For example, in a standard four-cylinder engine, the two middle cylinders can be deactivated. In deactivated cylinders, the valves are kept closed to trap exhaust gas to keep it warm for when it’s reactivated. Without fuel being injected into the cylinder, the mechanism of using fuel to wash off deposits is lost; good quality additised fuel, which includes friction modifiers and anti-wear chemistry, would be extremely beneficial.
Afton Chemical GD1 Clean Winner – Ricardo Video Series: Gasoline Particulate Filters
GDI engines tend to produce more particulates than PFI engines. This is because there is less time for the fuel to evaporate and mix inside the combustion chamber. A gasoline particulate filter is an after-treatment system applied to an engine to capture and control the particulate matter in the exhaust. It acts as a store and converts carbon-based particulate, or soot, into carbon dioxide by burning it. We tend to see higher particle numbers in GDI engines - which creates the need for gasoline particulate filters. Having good quality fuel with deposit control additives will be essential to prevent deposits, maintain robust GPF performance and minimise fuel consumption in all conditions.