High Pressure Direct Injection (HPDI) is a dual fuel technology that introduces gas at high pressure directly into the combustion chamber of a diesel engine. It allows for a small amount of diesel as the ignition source and large amounts of gas to be delivered directly to the engine cylinder.

On an HPDI engine, the existing injector is replaced by a HPDI injector. This allows for both gas and diesel to be injected directly into the combustion chamber on the engine.

HPDI engines run on up to 95 percent natural gas over the drive cycle.

The direct injection of the gas into the cylinder provides the engine performance comparable to a diesel engine in terms of power, transient response and torque, yet with the benefits of clean burning gas at significantly lower fuel costs.

As publicly announced, Caterpillar is partnering with Westport to develop the HPDI technology for both rail and mobile off-highway markets.

Both Caterpillar DGB and HPDI dual fuel technologies allow Caterpillar customers to use natural gas as a revolutionary fuel over the years to come. This is a new era where natural gas will be a major fuel source and bring significant bottom line cost savings to their businesses.