Internal Combustion (IC) Engine

Automotive Engine Design

It is an exciting time to be an automotive powertrain engineer, with many of the fundamental decisions that were made 50 or even 100 years being revisited, and many new options being explored thanks to the advent of new materials and advanced sensors and controls.

Fortunately, the ability to analytically evaluate candidate technologies and to fine-tune designs is keeping up with the need to explore new ideas.

A demonstration model is available to serve as a starting point for your explorations. While it is based on a four-stroke Otto cycle gasoline engine with 6 inline cylinders, the methods can be repurposed or extended to other cycles and configurations.

This FloCAD®-based model is built to explore short time scale events such as pressure waves within intake and exhaust runners, such that volumetric efficiencies and engine performance can be estimated. To do so, it models the transient actions of each of six cylinders independently through each stroke. Nonetheless, run times are fast enough (on the order of minutes) that parametric variations can be quickly explored. The focus of the problem is on the very short time‐scale events including pressure waves in the intake and exhaust runners. Details of flows, combustion, and heat transfer within the cylinder itself have been greatly simplified to preserve the focus on the air supply and exhaust systems.

Click here to download this sample from our support forum

This model was developed as a by‐product of an investigation of fast‐transient interactions within a turbocharged automotive engine.

Postprocessed Sinaps® Diagram showing temperatures and flows

Postprocessed FloCAD® diagram (sketch-pad mode) showing temperatures and flows

Pressure/flow profile for 720 degrees of crank rotation

Pressure/flow profile for 720 degrees of crank rotation (6000rpm, Cylinder #1)

dispersed vs. coalesced front

Tuesday, June 26, 2018, 1-2pm PT, 4-5pm ET

This webinar describes flat-front modeling, including where it is useful and how it works. A flat-front assumption is a specialized two-phase flow method that is particularly useful in the priming (filling or re-filling with liquid) of gas-filled or evacuated lines. It also finds use in simulating the gas purging of liquid-filled lines, and in modeling vertical large-diameter piping.

Prerequisites: It is helpful to have a background in two-phase flow, and to have some previous experience with FloCAD Pipes.

Register here for this webinar

FloCAD model of a loop heat pipe

Since a significant portion of LHPs consists of simple tubing, they are more flexible and easier to integrate into thermal structures than their traditional linear cousins: constant conductance and variable conductance heat pipes (CCHPs, VCHPs). LHPs are also less constrained by orientation and able to transport more power. LHPs have been used successfully in many applications, and have become a proven tool for spacecraft thermal control systems.

However, LHPs are not simple, neither in the details of their evaporator and compensation chamber (CC) structures nor in their surprising range of behaviors. Furthermore, there are uncertainties in their performance that must be treated with safety factors and bracketing methods for design verification.

Fortunately, some of the authors of CRTech fluid analysis tools also happened to have been involved in the early days of LHP technology development, so it is no accident that Thermal Desktop ("TD") and FloCAD have the unique capabilities necessary to model LHPs. Some features are useful at a system level analysis (including preliminary design), and others are necessary to achieve a detailed level of simulation (transients, off-design, condenser gradients).

CRTech is offering a four-part webinar series on LHPs and approaches to modeling them. Each webinar is designed to be attended in the order they were presented. While the first webinar presumes little knowledge of LHPs or their analysis, for the last three webinars you are presumed to have a basic knowledge TD/FloCAD two-phase modeling.

Part 1 provides an overview of LHP operation and unique characteristics
Part 2 introduces system-level modeling of LHPs using TD/FloCAD.
Part 3 covers an important aspect of getting the right answers: back-conduction and core state variability.
Part 4 covers detailed modeling of LHPs in TD/FloCAD such that transient operations such as start-up, gravity assist, and thermostatic control can be simulated.