EngMod2T

Detailed Description

  Engine Layouts

The current version of the software can simulate engines ranging from 1 to 8 cylinders with the following layouts:

  • Inline Engine
  • Vee Engine
  • Boxer Engine with a choice of common or separate crankcases

It has built in calculators for basic head shapes, crankcase compression ratio and target BMEP

 

 

 

Types of Inlet Systems

The following is a brief summary of the available inlet systems:

  • Separate Inlets
  • Separate inlets with a common air box
  • Manifold Inlet Systems
  • All intakes can have: Throttle valves and/or boost bottles

 

 

 

Types of Inlet Ports
  • Reed Valve - Case Reed
  • Reed Valve - Cylinder Reed
  • Piston Port
  • Rotary Disc Valve
  • Rotary Shaft Valve
  • Rotary Drum Valve

EngMod2T is one of the very few programs that model cylinder reed valves correctly with a combination of cylinder ports, Boyesen ports and floor ports.

 

 

 

Scavenging Model

The scavenging model is based on the Blair model with some refinements. It is based on measurements in a special type of test apparatus.

Transfer Ports

The software can model from 2 to 12 ports

 

  Combustion Modeling

Two types of combustion modeling is available and both are based on the typical two-zone model (a burnt and an unburnt zone):

  • Prescribed combustion depending on user input like the Vibe (Wiebe) values and the delay and combustion duration periods.
  • Turbulent entrainment combustion which uses turbulence modeling and mass entrainment into the flame front to model the combustion process.
 

 

 

Exhaust Ports

The exhaust ports fall into three main classes:

  • Single Main Window with/without auxiliary ports
  • Bridged Main Window with/without auxiliary ports
  • Arbitrary shape port modelled as a user defined profile

The first two types also has the option of having a powervalve. The powervalve can be of the governor type (mechanical or servo motor) or of the pneumatic type. It can be in the main port only or also in the auxiliary ports.

Exhaust Systems

The available exhaust systems fall into three main classes:

  • Single Pipe per cylinder
  • Branch manifold
  • Log manifold

Each class can be further divided into the following types:

  • Tuned pipe - the main or collector pipe can be configured as a tuned pipe.
  • Open pipe - the main or collector pipe can be configured as an open pipe
  • Box pipe - the main or collector pipe has a box or plenum in it.
  • Silencer pipe - any one of the above pipes can terminate in a silencer.

There is also a utility that can generate a tuned pipe based on one of the following 3 models:

  • Blair pipe - the pipe is based on the guidelines as presented by the late Prof GP Blair.
  • Modern pipe - the pipe is based on the multi diffuser layout as was state of the art in the 90's.
  • High Performance pipe - the pipe is based on the state of the art as it is currently.

  Turbocharger Modeling

The current release allows for the modeling of a single turbocharger with or without Charge air cooler (intercooler) and wastegate. Software is included to digitize the compressor and turbine characteristics.

 

The exhaust system can be modelled as straight pipes or tuned pipes. The figure shows three of the tuned pipe options available for an I4 engine.

As part of the pre-processor, Dat2T, there is a utility to verify the design:

To use a compressor map as part of the simulation it has to be extrapolated into the surge region and to the negative (reverse) flow region. The following is an example of such a digitized and extrapolated map:

To use a turbine map as part of the simulation it has to be digitized. As it is very difficult to obtain a full turbine map, the software currently uses an approximation known as the "swallowing curve". The following is an example of such a digitized swallowing curve:

 

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