Ideally, the air-fuel charge in the cylinder is stoichiometric. That is a ratio of 14 parts air and one part fuel. In practice, the air charge will be greater than14 parts to favor more complete combustion to limit carbon monoxide, CO, air pollution. With today’s fuel injection system, the fuel hydrocarbon, is in a droplet form, and the droplets combust in the outer edge which diminishes the available fuel for quick combustion. And, the time period available for effective combustion is limited to the time of spark strike to piston to top center. Figuratively, the cylinder is in the power charge state. which is effectively the compression of a spring, and exhibits reverse torque. Forward torque develops after the piston goes over top center as the compressed gas spring releases pushing the piston down.
Posts