Testing Engine Compatibility with HVO Fuel

As the United Kingdom marches steadily towards a net-zero future, businesses and individuals alike are exploring cleaner fuel alternatives to reduce carbon footprints. Among these alternatives, HVO fuel (Hydrotreated Vegetable Oil) has gained significant traction. Touted as a drop-in replacement for diesel, HVO offers impressive environmental benefits. But before making the switch, one crucial step stands out — testing engine compatibility with HVO fuel.

This article delves deep into how UK-based users can safely and effectively test HVO fuel compatibility in their engines, whether for commercial fleets, agricultural machinery, or backup generators.

What Is HVO Fuel?

Hydrotreated Vegetable Oil (HVO) is a renewable diesel made by hydrotreating waste animal fats and vegetable oils. Unlike conventional biodiesel (FAME), HVO offers superior cold weather performance, a longer shelf life, and cleaner combustion. It’s paraffinic, which means it burns more efficiently and produces fewer particulates and nitrogen oxides.

Why Engine Compatibility Testing Is Essential

While HVO is marketed as a drop-in replacement for fossil diesel, that doesn’t always mean it’s instantly plug-and-play for every engine. Here’s why testing is non-negotiable:

• Engine Materials: Older engines might contain rubber or polymer seals incompatible with paraffinic fuels.

• Fuel System Design: High-pressure common rail systems may behave differently when lubricity or density changes.

• Warranty Protection: Manufacturers may require evidence of compatibility testing to maintain warranty coverage.

• Operational Safety: Fuel leaks, pressure drops, or injector failures due to incompatibility can be avoided with pre-emptive testing.

Step-by-Step Process: Testing Engine Compatibility with HVO

1. Consult Your Manufacturer or Engine OEM

Many major engine manufacturers (including Cummins, Volvo, Scania, John Deere, and Perkins) have issued technical bulletins or approval lists regarding HVO use. Always check:

• Engine make and model

• Year of manufacture

• Fuel system type

If your OEM has formally approved HVO (EN 15940 standard), you’re likely good to go. If not, proceed with a controlled trial.

2. Conduct a Fuel System Assessment

Before introducing HVO into your system, carry out a comprehensive fuel system audit, especially for:

• Fuel filters: HVO has a cleaning effect, which may dislodge sludge from diesel tanks.

• Seals and gaskets: Test rubber compatibility.

• Fuel pumps and injectors: Ensure lubrication levels match requirements.

For fleets, you may consider pulling a sample from the tank and running materials compatibility testing on hoses and gaskets.

3. Trial HVO on a Single Engine or Vehicle

Don’t overhaul your entire operation at once. Pick one unit—ideally out of warranty—and:

• Drain existing diesel fuel.

• Flush fuel lines and filters.

• Fill with HVO (neat or blended with diesel, depending on the engine’s requirement).

• Log all operating parameters: fuel consumption, emissions, idle behaviour, cold starts, engine noise, etc.

Run this trial over a period of 2–4 weeks to assess real-world impacts.

4. Monitor Engine Performance and Fuel Economy

Use diagnostic tools or telematics systems to track:

• Exhaust emissions (CO₂, NOx, PM)

• Fuel injection pressure

• Start-up efficiency

• Throttle response

• Fuel economy over similar workloads

In most cases, UK trials have shown no negative impact on performance — and in some situations, even a slight improvement in cold start and combustion cleanliness.

5. Check Oil Analysis and Fuel Filter Conditions

After 100+ hours of operation, have your engine oil analysed to check for:

• Soot content

• Fuel dilution

• Lubricity impact

Also inspect fuel filters for any signs of clogging — particularly if the engine was previously run on low-grade red diesel or stored fuel. HVO’s detergent effect can dislodge existing contaminants.

6. Document the Process

For fleet managers or facility operators, maintaining a record of the compatibility testing is crucial. Include:

• Engine data (make, model, age)

• Fuel source and specifications

• Monitoring tools used

• Performance observations

• Supplier documentation

This documentation helps satisfy insurers, auditors, and compliance officers and supports warranty discussions.

UK Focus: Compliance, Support, and Supply

HVO Fuel in the UK

In the UK, certified HVO suppliers comply with EN 15940 standards and RTFO (Renewable Transport Fuel Obligation) schemes. Reputable names include Green Biofuels, Crown Oil, and Certas Energy, among others.

Compliance and Reporting

If your business is subject to sustainability reporting, you’ll be glad to know HVO use can be credited towards Scope 1 emissions reductions. Ensure your fuel supplier provides:

• Greenhouse Gas (GHG) emissions statements

• Origin tracking certificates (i.e., palm-free, waste-based)

Common Compatibility Issues (And Solutions)

Final Thoughts: Future-Proofing with HVO

Testing engine compatibility with HVO fuel is not just a technical exercise — it’s a forward-looking decision that aligns with the UK’s decarbonisation goals. With most modern engines proving compatible, and supplier networks expanding rapidly, HVO is set to become a mainstream fuel in agriculture, construction, haulage, and standby power sectors.

By taking the time to test properly, you ensure your operations transition smoothly and responsibly — without compromising equipment performance or safety.