Kramer graph
A Kramer graph is a specific multiple-line 2D geometric symbolic representation of the characteristics of intake, scavenging and exhaust components in a two-stroke cycle engine.
They are typically used to visualize the opening time versus area and/ or lift of the following components:
Intake port / valve
Scavenging port / valve
Exhaust port / valve
Reed inlet valve
Rotary inlet valve
They do not show the specific configuration of ports like in a port-map, which enables it to illustrate a more useful visualization of port area distribution,
This could be useful because different types of port configurations could have the same opening time and area.
In these graphs the X-axis represents the crankshaft angle (θ) in degrees, and the left Y-axis represents the open area in any square unit of measure such as cm². To discern the different types of ports each type is given a designated color.
For example (commonly used):
Blue - Intake system
Green - Scavenging system
Red - Exhaust system