UCS Grades States on School Bus Fleet Pollution
Segway in EasyConnect II Inter-modal Commuting Test in San Francisco Area

Westport Innovations Gets C$22.1M Investment; Funds for Commercial Launch of HPDI LNG Trucks

Westport Innovations, a global leader in gaseous-fueled engines and fuel systems, and Perseus LLC, a US.-based private equity fund management company, have completed definitive agreements for a strategic investment of approximately C$22.1 million (US$20.1 million) in Westport to be completed in two separate tranches.

The closing of the first tranche of C$13.8 million is committed and will be funded on or before 15 July 2006. The parties also have agreed to a further investment of approximately C$8.3 million to be used to pursue new business opportunities, subject to shareholder approval.

The proceeds will fund the commercial launch of High-Pressure Direct-Injection (HPDI) LNG truck engines in North America and Australia, development of Westport’s international business ventures, and general working capital requirements.

HPDI: The diesel fuel is delivered just prior to top-dead-center, followed by the main fuel quantity of natural gas.

High Pressure Direct Injection relies on late-cycle high-pressure injection of a gaseous fuel, such as natural gas, into the combustion chamber of a diesel engine.

Natural gas has a higher ignition temperature than diesel (1,000° C vs. 500° C) and will not easily ignite at the temperatures and pressures in the combustion chamber of a normal diesel engine. To assist with the ignition of natural gas, a small amount of diesel fuel is injected into the engine cylinder using a dual-concentric needle injector the same injector followed by the main natural gas fuel injection. The diesel fuel is delivered just prior to top-dead-center, followed by the main fuel quantity of natural gas.

The diesel fuel acts as a pilot or “liquid spark plug” which ignites rapidly the hot combustion products then igniting the natural gas.

HPDI gives the engine the efficiency and low-speed torque advantages of compression ignition while using natural gas as the primary fuel. With HPDI engines, approximately 95% of the diesel fuel consumed in a diesel engine is displaced with natural gas.

Perseus also has successful holdings in Clean Energy Fuels Corp., of which both Westport and Perseus are shareholders.


Rafael Seidl

For this to be a commercial success in the trucking business, the cost of LNG operations would have to be within just a few percent of those for diesel. That seems a tall order, given the additional infrastructure (expensive cryotank etc.) needed on-board plus the fuel liquefaction and distribution overheads.

Perhaps the system is not intended for long-haul trucking but rather for specialty fleets such as city buses, school buses, garbage trucks and stop-and-go delivery trucks that are more sensitive to emissions and can operate their own filling stations. Crash safety is even more important for LNG than it is for CNG or gasoline/diesel.

Note that the low temperature of LNG (~160 Kelvin) means it must be boiled off and heated prior to injection. In theory, the stored cold energy of ~860 kJ/kg could be put to good use, e.g. in supplemental intercooler elements, to reduce NOx emissions and/or increase specific power. Multiple elements should be used in alternation so the hot air supply from the turbocompressor can melt any ice that might form on them due to humidity in the ambient air. However, alternation exposes such elements to thermal cycling.


Combustion of natural gas with lack of oxygen – exactly what is going on in diesel-like fuel injection, produces ultra fine carbon particles. Anyone have PM2.5 data on this engine?

Rafael Seidl

Andrey -

there is no "lack of oxygen". These modified diesel engines are operated with air excess, it's just that methane is hard to ignite (high octane = low cetane number). The amount of diesel burnt here is minimal, just enough to establish a flame front that then progresses outward as in a spark ignition engine. The PM2.5 emissions will be 1-2 orders of magnitude below those of the same engine running on diesel only. I suspect you'd be hard pressed to even detect them.

Btw, stationary gas engines often use spark plugs instead, but in that context they are reaching technological limits related to life expectancy and fouling. The Techn. Univ. Vienna (Austria) has collaborated with a number of local businesses to deliver a reliable laser ignition system but for now, the cost remains high. The advantage is that the ignition locus can be in the center of the combustion chamber rather than near a boundary. With special lenses, a single laser can even generate multiple ignition points. All this yields a better approximation of efficient isochoric combustion, with bmeps in excess of 24 bar and NOx levels 80% lower than with diesel pilot injections.


I am not aware of anyone using laser ignition in mobile gas engine research just yet.



You are talking about pilot diesel or spark ignition of mixed NG/air mixture, in most cases lean below self-detonation limit. These are marvelously clean and efficient engines indeed.

Westport together with Cummings produces such engines, but their initial invention, which they are pushing for over 10 years, is direct injection NG engine. This one inject highly compressed NG near the TDC, and ignition is facilitated by prior injection of small amount of diesel fuel (they also have ignition variety for small engines by glow plug). Thus combustion occurs in border layer of NG during diffusing with air – very close to combustion of diesel fuel fumes diffusing to air near surface of fuel droplet. This layer of incomplete mixed air and NG has substantial rich zone, hence my concern for ultra small PM.

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.


Post a comment

Your Information

(Name is required. Email address will not be displayed with the comment.)