We are proud to announce the launch of our premium aftermarket exhaust range, developed exclusively for Euro 5 TX4 models. This latest addition reinforces our ongoing commitment to delivering high-quality, fully compliant, and durable solutions tailored specifically to the demanding needs of the UK taxi sector.
Our new range includes fully certified:
- Diesel Particulate Filters (DPF®)
- Diesel Oxidation Catalysts (DOC)
- Exhaust Silencers
HJS identified a clear gap in the UK aftermarket: the absence of quality Euro 5 replacement DPFs, DOCs and silencers for the TX4 platform. The shortfall became apparent during our work on our TX4 Euro 6 emission upgrade programme in London. Despite extensive research across the marketplace, no aftermarket or OE replacement products were found.
Drawing on our decades of aftermarket manufacturing expertise, we took the strategic decision to engineer the solution in-house. The programme began at HJS UK, where initial prototypes were developed and subjected to comprehensive internal testing. Following successful evaluation, the components were transferred to our headquarters in Germany for advanced prototyping and detailed flow analysis.
After rigorous durability and performance testing, the DPF, DOC and silencer assemblies were submitted for homologation, securing full approval and E-mark certification to meet UK regulatory requirements. Notably, the HJS DPF is manufactured using high-grade silicon carbide substrate technology — a material recognised for its superior thermal resistance, filtration efficiency and long-term reliability compared with lower-specification alternatives available in the marketplace.
The project also supports our Euro 6 retrofit upgrades for TX4 taxis operating in London. Under strict requirements set by Transport for London (TfL), Euro 5 diesel taxis undergoing conversion must replace both the DOC and DPF to achieve compliance. Retrofitting provides a highly cost-effective pathway for drivers to meet Euro 6 emissions standards, extend vehicle lifespan and significantly reduce environmental impact — contributing to improved urban air quality across the capital.
With certified components, OEM-level quality and a focused commitment to the TX4 platform, HJS reinforces its position as a trusted exhaust and emissions partner for the UK taxi industry.
