Modern petrol engines typically use more air than petrol compared to early engines like two-stroke motorcycles and old cars due to advancements in engine technology and the implementation of more efficient combustion processes. Here are a few key reasons for this difference:
Combustion Efficiency: Modern engines utilize techniques such as direct fuel injection, variable valve timing, and improved intake/exhaust systems. These advancements allow for better control over the air-fuel mixture, resulting in more complete and efficient combustion. By increasing the amount of air entering the engine, a higher air-to-fuel ratio can be achieved, leading to better fuel economy and reduced emissions.
Emissions Regulations: Stricter emissions regulations have necessitated the development of cleaner-burning engines. By increasing the amount of air relative to the fuel, the combustion process can be optimized to minimize harmful emissions such as carbon monoxide (CO), nitrogen oxides (NOx), and unburned hydrocarbons (HC). Leaner air-fuel mixtures tend to produce lower emissions, making it necessary to adjust the air-to-fuel ratio accordingly.
Improved Fuel Economy: Modern engines aim to achieve better fuel efficiency to meet the demands for reduced fuel consumption and increased mileage. By using a leaner air-fuel mixture, less fuel is required to produce the same amount of power. This helps improve fuel economy and reduces the overall cost of driving.
Environmental Considerations: The focus on environmental sustainability and reducing the carbon footprint has led to the development of technologies that promote cleaner and more efficient combustion. By using a leaner air-fuel ratio, the amount of CO2 emitted per unit of power output can be reduced.
It's worth noting that two-stroke motorcycles and older cars often used simpler carburetor-based systems that relied on a fixed air-fuel mixture, which was generally richer than what modern engines use. These older engines were less efficient in terms of fuel consumption and emissions compared to their modern counterparts.
Overall, the shift towards leaner air-fuel mixtures in modern petrol engines is driven by the need for improved efficiency, reduced emissions, and compliance with stricter environmental regulations.