Other Transportation Uses
Besides their use in catalytic converters, fuel cells and gasoline refining, Platinum Group Metals also play a role in the manufacture of other automotive products, such as antilock braking systems (ABS) to improve safety and control, airbag initiators, engine management systems, and spark plugs.
Antilock Braking Systems
ABSs eliminate or greatly reduce the problem of brakes locking in emergency stops. With conventional brakes, the wheel may lock, possibly causing the car to go into an uncontrollable skid.
ABS uses computer technology to monitor and control the application of the brakes with hydraulic pulses of pressure which allow for braking without locking.
Due to its conductivity, durability and resistance to corrosion, palladium is used in ABS systems' electronic components.
Airbag initiators may only ever be used once and after a long period of inaction. So the electronic components that make them work must be durable and reliable which is why platinum – with its corrosion resistance, durability and conductivity – is used.
Civilian air fleets are primarily propelled by turbofan jet engines.
Today, research and development efforts are looking at the ways in which ruthenium's high melting point, temperature stability, corrosion resistance and hardness can be used in aircraft turbine blades. Adding ruthenium to turbine blades would allow the engine to operate at higher temperatures which mean more efficient burning of fuel, reducing its consumption and the emission of CO2.
Engine Management Systems
Engine management systems have greatly improved the reliability of cars and reduced the need for maintenance. Employing up to 50 microprocessors, various systems help regulate fuel intake, control engine sparking and diagnose problems.
Due to their conductivity and durability, platinum and palladium are used in engine management systems' electronic components.
Platinum is used for a variety of sensor applications, including oxygen sensors in car exhaust systems. Oxygen sensors are used to help run a gasoline engine more efficiently. The oxygen content is related to the amount of unburned fuel remaining in the engine. The sensor is made of a porous platinum coating on both the inside and the outside of the zirconia tube. The outside is exposed to the exhaust, whereas the inside remains exposed to normal air. The zirconia tube is heated by the exhaust and becomes an ionic conductor. As the oxygen content in the atmosphere of each platinum sensor is different, there will be a potential difference between them. This difference is monitored, and changes are used to control the fuel flow through the engine to ensure that the gas/fuel mixture allows for complete combustion of the fuel.
Modern car ignition is dependent on the creation of a spark at exactly the right moment so that the fuel/air mixture in the engine can be efficiently converted into power.
Spark plugs create the high-voltage spark necessary whilst withstanding extremes of heat and pressure. The key component of a spark plug is the central electrode that carries the electric charge to the tip. With their high conductivity, high melting points, high temperature stability and corrosion resistance, platinum, rhodium and iridium are ideal for firing tips (the active components in the plugs).
Platinum electrodes have a higher durability than traditional copper electrodes. This enables manufacturers to reduce electrode diameter, which in turn decreases the voltage required. The high durability of platinum can also improve combustion performance over the life of the spark plug, reducing emissions.
The use of electrodes manufactured from iridium or rhodium alloy facilitates further reductions in electrode diameter and gains in durability.