Kramer graph
Encyclopedia
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:
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):
Kramer graphs are named after Dutch engineer H. Kramer, who is considered to have been the first to use this type of graph in a publication on the effect of port shape and area on two-stroke cycle engine performance.
2D geometric model
A 2D geometric model is a geometric model of an object as two-dimensional figure, usually on the Euclidean or Cartesian plane.Even though all material objects are three-dimensional, a 2D geometric model is often adequate for certain flat objects, such as paper cut-outs and machine parts made of...
symbolic representation
Depiction
Depiction is meaning conveyed through pictures. Basically, a picture maps an object to a two-dimensional scheme or picture plane. Pictures are made with various materials and techniques, such as painting, drawing, or prints mosaics, tapestries, stained glass, and collages of unusual and disparate...
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 valveReed valveReed valves are a type of check valve which restrict the flow of fluids to a single direction, opening and closing under changing pressure on each face...
- Rotary inlet valve
They do not show the specific configuration of ports like in a port-map
Port-map
In two-stroke engine technology a Port-map is a diagram which shows the ports that are cut in to the cylinder of an engine.A port-map can be useful to determine opening/closing-timing and the area of specific ports....
, 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
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
, 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
- Purple - Inlet valve
Kramer graphs are named after Dutch engineer H. Kramer, who is considered to have been the first to use this type of graph in a publication on the effect of port shape and area on two-stroke cycle engine performance.