Bi-Injection

A Technical Synergy for Combining Performance and Ecology

Context and Technical Principles

Bi-injection, or dual injection, is a technology that combines two injection methods to meet performance demands and reduce pollutant emissions. To comply with Euro 6 standards and minimize fine particles, manufacturers integrate both direct and indirect injection in the same engine.

Direct injection, operating at very high pressure (up to 200 bar), sprays fuel directly into the cylinder. This process optimizes combustion and provides efficient cooling of the chambers under full load. Conversely, indirect injection, operating at low pressure (about 3.5 bar), injects fuel into the intake manifold. It offers a more homogeneous mix, reducing fine particle formation and improving energy efficiency.

Environmental and Performance Benefits

The combination of both injection systems allows for the best of both worlds. By intelligently regulating the switch between direct and indirect injection based on engine conditions—whether during startup, cold operation, or full load—the engine can optimize combustion according to its needs. During startup or cold operation, direct injection is often preferred to avoid wall effects and to accelerate the heating of the catalytic converter. In low or medium load situations, indirect injection helps prepare a more homogeneous mixture, thus limiting pollutant emissions. Finally, under heavy load, direct injection vaporizes fuel directly into the cylinder, promoting optimal cooling of the combustion chamber. This heat dissipation limits mixture enrichment, reducing fuel consumption while protecting the turbocharger and preventing the risk of auto-ignition.

Concrete Examples in the Automotive Industry

Several notable engines adopt bi-injection to combine performance with emissions control. For instance, the 2.5 TFSI in the Audi RS3 leverages this technology to deliver impressive power and responsiveness while optimizing its energy efficiency. Similarly, the 2.0T in the A45 AMG, recognized as one of the most powerful four-cylinder engines on the market, benefits from advanced injection management to maximize specific power without compromising reliability. These examples illustrate how bi-injection is becoming an increasingly essential standard for high-performance and sports engines.

WOT's Innovative Approach

At WOT, we have developed an advanced approach to bi-injection, pushing its conventional boundaries. Unlike original engine maps, our reprogramming strategy activates indirect injection even under full load. The result?

• Better atomization of fuel for more efficient combustion.

• Optimized compensation for turbo pressure increases.

• Improved performance without compromising reliability.

This approach is also effective when using alternative fuels, such as bioethanol, which, due to its lower energy density, requires about 25% more fuel to produce equivalent power.

Conclusion

Bi-injection represents a major technological advancement, enabling manufacturers to reconcile environmental requirements with optimized performance. At WOT Engineering, our expertise in reprogramming allows us to exploit this technology beyond its conventional use by activating indirect injection under full load. The result: significant power gains without compromising emission standards compliance. This approach ensures maximum performance for our clients while adhering to Euro regulations.