Mahle Filter Systems India Ltd Mulshi, Pune, Maharashtra

The significance of exhaust gas turbochargers in future high-efficiency combustion engines is increasingly greatly. Without exhaust gas turbocharging, downsizing gasoline engines is unthinkable. Almost all modern diesel engines are turbocharged. Turbochargers guarantee an excellent torque curve and high engine output. They are also indispensable for complying with ever stricter emissions limits.

In diesel engines, steel pistons provide significant potential for reducing CO2 emissions in comparison with the aluminum pistons that have been typical up to now. After a long history of positive results in commercial vehicles, MAHLE has therefore developed steel pistons for passenger car diesel engines to the point of series production readiness. Significant advantages result from the frictional loss. Thermodynamic conditions additionally result in advantages in combustion that lead to a reduction in fuel consumption and emissions levels. The lower compression height of a steel piston can also be utilized to increase the swept volume or to decrease the height of the engine.

The term cam follower is a generic term for the various elements that are moved directly by the cam lobe. They follow the cam lift and transmit the motion to the downstream valve components. Cam followers include tappets, buckets, and levers in a wide range of designs.

In addition to the task of sealing off the combustion chamber, piston rings also have the function of dissipating the heat that arises in the piston to the cylinder surface and that of controlling the oil balance.

The piston pin, as the link between the piston and connecting rod, is subjected to extremely high loads in alternating directions. In order to be able to withstand these stresses and ever-increasing combustion pressures, it is essential that the load capacity of these components be permanently optimized.

The demands placed on pistons for gasoline engines have been continuously tightened over the past years. Higher performance requirements trigger increased thermal loads. At the same time, downsizing concepts have increased mean and peak pressures, while high-speed concepts impose greater inertia forces.

A central aspect of fuel management is the efficient filtration of the fuel, in order to protect the engine and its components from contamination and damage. As manufacturers increasingly pursue a strategy of identical parts or modular design, the same engine is being used in more and more regions of the world. The fuel quality varies accordingly, at times due to biocomponents in the fuel. The water content plays a role along with dirt particles. Water separation systems can pave the way for the global application of an engine while making it possible to use biodiesel.

The state of the art in motorsport is now used in highly loaded series production engines as well: the forged piston. For the same alloy, they have a finer microstructure than cast pistons. The production process results in greater strength. As a result, the pistons can withstand even the high loads in motorsport and in engines with exceptionally high specific output. They are already being used today in sporty series vehicles with over 130 kWL. Another advantage of forged pistons is the potential to produce thinner walls, thus reducing weight.

The reduction of pollutant emissions particularly of nitrogen oxide emissions in diesel engines is an important task within the development process. Engine-internal methods such as exhaust gas recirculation seek to reduce raw emissions during combustion itself.

The electric wastegate actuator from MAHLE ensures the best possible interaction between the combustion engine and turbocharger, especially in downsizing engines. This novel technology allows very high actuation speeds and very precise boost pressure regulation. The electrical actuator can reach any desired wastegate position in a flash, regardless of the negative or positive system pressure. Its high clamping force ensures minimal leakage and consequently rapid boost pressure build-up. The result is very spontaneous responsiveness. Another advantage of the electrical actuator is the ability to open the wastegate completely. This allows the catalytic converter to light off quickly, thereby reducing exhaust gas emissions and fuel consumption, which is crucial to customers.

Injection pressures of up to 2,200 bar, mean pressures of up to 31 bar, peak pressures of up to 210 bar, specific power output of up to 100 kW per liter, and ever lower exhaust gas emissions—these are the current requirements for modern passenger car diesel engines.

Due to the lift motion of the piston and piston rings, their partner the cylinder surface is also subject to high mechanical loads and must withstand increased ignition pressures and speeds. In order to reduce wear, the running surface should be smooth and the lubrication between the sliding partners must be ensured. The type and quality of the running surface effects oil consumption as well as the wear of the two components.

The connecting rod connects the piston to the crankshaft and consists of the small end and big end bores as well as the shank. As the element that transmits forces and motions, it is subjected to alternating stresses and continuously increasing performance. The trend for connecting rods, however, is toward ever lighter components. The MAHLE connecting rods product range accommodates this challenge. With high-strength and innovative materials, MAHLE can more than fulfill the current requirements.

One of the chief measures used to reduce fuel consumption and thus CO2 emissions is to reduce the swept volume, typically in combination with turbocharging, in order to maintain or improve power output and torque. As the degree of turbocharging increases, the necessity of cooling the compressed air grows simultaneously. Charge air cooling therefore takes on an ever more critical role. The latest stage of development at MAHLE includes indirect cascaded charge air cooling, integrated in the intake pipe, which provides minimal pressure loss and significant packaging advantages. It produces charge air temperatures close to that of the coolant by using a two-stage cooling process.

From a purely mechanical standpoint, the task of the camshaft is to convert the rotary motion of the crankshaft into an oscillating motion of the cam follower by means of the cam profile. The shape of the cam profile defines the valve lift and is thus a fundamental adjustment parameter in the design of the gas exchange and thus of the combustion process.

The primary function of a bearing is to support the moving parts while absorbing and transferring occurring forces. But modern engines demand more than that. Load capacity must be improved and wear and friction must be lowered in order to meet the current and future requirements for CO2 reduction. Stop-start or hybrid systems present a special challenge as the combustion engine is frequently switched on and off. Especially during the starting process, the bearings run through the range of mixed friction and must withstand particularly high loads.

MAHLE aluminum pistons for passenger car diesel engines are cast from high temperature-resistant aluminum alloys. Standard features include ring carriers made of high-strength cast iron to increase the wear resistance of the first ring groove, salt core cooling channels or cooled ring carriers, and MAHLE EvoGlide coatings to optimize the running characteristics of the skirt. For high-performance engines, MAHLE additionally uses bushings in the piston pin bores.

Before unfiltered air enters the combustion chamber, it must be fed through the engine compartment and cleaned of dirt particles as efficiently as possible.

Modern engines place greater requirements on cylinder components than ever before: at higher operating temperatures and pressures, emissions must be reduced. This calls for innovative concepts and materials with unprecedented high performance. Thinking in systems and integral concepts also considerably contributes to achieving these goals. Additional performance potential can only be tapped when components are optimally tuned.

Valves, valve guides, and valve seat inserts work as an assembly to seal off the combustion chamber within the valve train. While the valve and valve seat insert perform the actual sealing function, the valve guide supports the motion of the valve.