Retrofit Technology
Direct injection (DI) is a technology that has shown the ability to greatly reduce emissions from two-stroke engines. In a DI system the carburetor is eliminated, and the fuel is introduced into the combustion chamber via an injector mounted in the top of the chamber’s cylinder head. This allows exhaust products to be scavenged from the cylinder using air only. Fuel is injected into the cylinder later in the cycle, greatly reducing the amount of unburned fuel that is allowed to escape during scavenging. Scavenging losses of unburned fuel are virtually eliminated, resulting in much lower hydrocarbon emissions and more efficient fuel consumption. The DI process allows for a locally rich region around the spark plug, eliminating the need for enrichment of the entire cylinder to achieve stable combustion. Elimination of rich air/fuel ratios significantly reduces carbon monoxide emissions.
Envirofit licenses the core of the direct injection system from Orbital Corporation. Orbital has been developing the patented "OCP™" (Orbital Combustion Process) for over 20 years, and their system is used in a variety of commercial and recreational market products. For more information on Orbital please visit www.orbeng.com.au.
DIRECT INJECTION VS. CARBURETION
DIRECT INJECTION
- Removal of spent exhaust products, known as "scavenging", occurs with fresh air only.
- Injection of fuel occurs after exhaust ports have closed.
CARBURETION
Carbureted engines "scavenge" with raw incoming air and fuel mixture, losing roughly 35% of the unburned mixture in the process.