Purpose, Function
Purifies contaminants in the exhaust gas by utilizing the chemical reactions of the three-way catalytic converter.
A WU-TWC and a TWC have been adopted.
The three-way catalyst is integrated with the exhaust manifold.
Because the catalyst receives the high temperature exhaust gas just after the gas is exhausted, it activates quickly and achieves an improved purification performance.
A single-nano catalyst has been adopted in which the purification performance can be maintained using less precious metal materials than conventional catalysts.
Construction
WU-TWC
The WU-TWC is installed to the rear of the engine.
The WU-TWC is integrated with the exhaust manifold.
TWC
The TWC is installed to the rear of the WU-TWC.
2WD
AWD
A single-nano catalyst has been adopted for the under-floor three-way catalyst. With a conventional three-way catalyst, the precious metals move and agglutinate to each other by the heat of the exhaust gas because they are structured such that they adhere on catalyst material. Therefore, it was necessary to use a large amount of precious metal because it is estimated that the purification performance lowers due to the decrease in the surface area of the precious metals. The single-nano catalyst is structured such that it embeds small precious metal particles into the catalyst material. Because the precious metal particles do not agglutinate on the surface of the three-way catalyst, it can maintain superior purification performance using less precious metal than the conventional system.
Operation
Contaminants in the exhaust gas (HC, CO, NOx) are purified by oxidization and deoxidization while they are passing through the catalytic converter.
Oxidization process
Noxious hydrocarbon (HC) and carbon monoxide (CO) are bound with oxygen and converted to non-noxious carbon dioxide and water.
O2+HC+CO>CO2+H2O
Deoxidization process
Noxious nitrogen oxide (NOx) is converted to non-noxious nitrogen and oxygen. A part of the oxygen generated in this process is used in the oxidization process.
NOx>N2+O2
Owner Maintenance Precautions
The owner or a qualified service technician should make these vehicle inspections
at the indicated intervals to ensure safe and dependable operation.
Bring any problem to the attention of an Authorized Mazda Dealer or qualified
service technician as soon as possible.
When Refueling
• Brake ...
Manifold Absolute Pressure (Map) Sensor
Purpose/Function
Detects the intake air pressure introduced into the cylinder as basic information
for mainly determining the fuel injection amount.
Detects the intake air pressure introduced into the cylinder and inputs it
to the PCM as an intake air pressure signal.
Cons ...
Crankshaft Position (CKP) Sensor
Purpose/Function
Detects the crankshaft speed as basic information for mainly determining
the fuel injection timing and ignition timing.
Detects the crankshaft speed and inputs it to the PCM as a CKP signal.
Construction
Installed on the side of the cylinder block (ri ...