Turbo Componentry

Cummins Turbo Technologies excels in the development of turbocharger components, meeting the requirements of diesel engine manufacturers who are looking for ways to reduce emissions while maintaining or improving fuel consumption, power density and reliability. Our extensive engineering & turbo expertise has grown from our humble Holset beginnings.

For more than 60 years, our components designers and engineers have innovated design methodologies. The result for the customer is improved fuel consumption, reduction in overall operating costs, downsized turbochargers and more intelligent actuators. Cummins Turbo Technologies’ components are tested individually, as part of the turbocharger sub-system and again at the full turbocharger level.

Industry-leading component technologies include:

Machined From Solid (MFS) impellers for high boost temperatures and highly cyclic applications.
Cast-iron compressors covers for high-temperature applications.
Compressor Map-Width Enhancement (MWE) provide wider maps compared to competition.
Command-valve wastegates allow wastegate operation at a wider range of engine speeds and loads.
Rotary valve and integrated systems for two-stage systems work together for optimal turbo efficiency.
Water cooled bearing and turbine housings for gas, marine and high temperature applications.
Electric actuators with feedback for rapid response, accuracy and provision of self diagnostics.
Axial and radial turbines for power turbines to suit packaging requirements and optimize turbocompound technology.
Variable Geometry nozzles provide thermal management of exhaust after treatment systems, drive Exhaust Gas Recirculation (EGR), provide higher boost at lower turbine speeds, enable engine braking and increases engine performance range.
Integrated, non-intrusive sensor systems control speed, performance and wear, even at low speeds.

This graphic is a representation of hydrodynamic floating ring technology

What are turbo bearings?

Turbo bearings are components that maintain efficiency and reduce emissions in turbochargers.
They ensure that turbochargers perform reliably and efficiently.
They control the high-speed rotation of the turbine and compressor wheels while minimizing friction and wear.

What is the role of turbo bearings in internal combustion engines (ICE)?

A turbocharger has two main components: a turbine and a compressor.
Exhaust gases drive the turbine, and the compressor squeezes intake air before it enters the engine’s cylinders.
Turbo bearings control the radial and axial motion of wheels and minimize friction losses, ensuring the turbine and compressor operate properly.
This occurs at high speeds with low-viscosity engine oils, high oil supply and gas temperatures above 760°C (1400°F).
Today’s turbo bearing technologies fall into two main categories: hydrodynamic bearings and rolling element bearings.

Role of turbo bearings in e-machines

BEVs and FCEVs don't use turbo bearings like ICE vehicles, but specialized applications may still benefit indirectly from them.
In hydrogen fuel cell turbomachines, oil-free air foil bearings are preferred to avoid fuel cell degradation from leaks.
These hydrodynamic air fan bearings (AFB) use air instead of oil.
This makes them ideal for FCEVs by forming a flexible air film that adapts to internal pressure.

Hydrodynamic bearings (journal bearings):

Floating rings or journal bearings are also known as hydrodynamic bearings.
They are the most widely used configuration in modern turbochargers.
Floating ring bearings control the rotor's radial motion using two oil films at the inner and outer diameters.
They work with a separate taper land thrust bearing to control axial motion.
Smaller turbochargers may use different hydrodynamic bearings, such as semi-floating, single-piece journal bearings or integrated, single-piece, semi-floating bearings with thrust pads on the end surfaces, to carry axial forces.

Rolling element bearings:

These bearings use a single cartridge with two rows of ceramic angular contact ball bearings, controlling both radial and axial rotor motion in one assembly.
An oil damper between the cartridge's outer diameter and the bearing housing extends bearing life and controls noise by reducing component stress.
Orifices in the cartridge's outer race regulate pressurized oil for lubrication.

Difference between the rolling element and hydrodynamic bearings:

Rolling element bearings can cost more but offer improved performance.
They reduce bearing loss and provide better control over radial and axial motion.
This helps reduce aerodynamic clearances and lower motion levels to boost the aerodynamic efficiency of turbochargers.
Rolling element bearings also enable operations when oil supply pressures are low.
They work with smaller power engine pumps, while delivering higher engine efficiency.
Manufacturers can choose the correct bearing by considering that engine efficiency can offset the higher initial bearing cost.