The Problem Statement is concluded by comparing two Internal Combustion Engine data mentioned below:

1. Pressure Crank Angle Diagram and

2. Slider Crank Mechanism analysis results

Pressure Crank Angle Diagram:

Here from the above Cylinder pressure data, we have

1. The peak pressure in the cylinder is at the TDC position of the Crank and is acting linear to the cylinder axis.

2. The pressure in the cylinder is significant only up to 50° of the Crank angles, which can be converted into useful rotary work.

Slider Crank Mechanism:

The slider Crank Mechanism is the only Kinematic Link that has been used for over a Century in the Internal Combustion Engines.

Let us consider a Slider Crank Mechanism with a crank-to-connecting rod length ratio of 1:3, and a constant dead load acting on the piston.

 Upon analysis, the crank experiences three types of force acting on it as, Compressive, Rotary, and Tensile forces, or a combination of Compressive and Rotary or Rotary and Tensile as indicated in the above-animated image, the compressive and tensile forces act in line with the crank (indicated in Red) and the rotary force acts normal to the crank (indicated in green).

 The Rotary Component is the only force that gets converted into useful output work, and this rotary component is at its peak when the Crank and Connecting Rod are Perpendicular to each other, that is around 71deg crank angle when the crank and connecting rod lengths are in the ratio of 1:3.

Here we can conclude for the power stroke of the engine.

1. At the TDC position, the crank experiences only compressive and no rotary force, resulting in Zero Work Output.

2. This slider crank mechanism delivers maximum work at a 71-degree crank angle when the crank and connecting rod are perpendicular to each other.

Upon comparing the findings between Pressure Crank Angle data and Slider Crank Mechanism characteristics we can conclude as below:

 Comparing points 1. We have: The peak pressure in the cylinder is reached at TDC where the crank experiences no rotary force and the peak pressure acts as a compressive force on the crank resulting in zero work output.

Comparing points 2. We have: When the slider crank mechanism is at its best position to deliver maximum output at a 71-degree crank angle, there is no significant pressure in the cylinder to generate useful work.

 Further, analyzing the slider crank mechanism MSC ADAMS software, for its ability to convert the linear force in the cylinder to rotary force useful work, we arrive at the results below:

 The simulation results are based on kinematic data as mentioned:   Crank Length - 100mm, C-Rod Length - 300mm and a Constant Load on piston - 100N.

The simulation results of Piston Displacement and Crank Torque plots are charted against Crank Angle.

 Problem Statement:

The Crank Torque plot shows how capable is the slider crank mechanism in transforming linear piston motion into useful rotary crank work, the plot says for the first 50deg of crank rotation in power stroke, the mechanism is capable of transforming less than 50% (from the area covered under the plot) of linear force to rotary torque, this shows that internal combustion engines using slider crank mechanism can never cross 50% efficiency.

Conclusion:

The engine efficiency can be improved if the area under the Crank Torque plot is increased by any mechanism.