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Study of a Pneumatic Hybrid aided by a FPGA Controlled Free Valve Technology System

Trajkovic, Sasa LU (2008)
Abstract
Urban traffic involves frequent acceleration and deceleration. During deceleration, the

energy previously used to accelerate the vehicle is mainly wasted on heat generated by

the friction brakes. If this energy that is wasted in traditional IC engines could be saved,

the fuel economy would improve. Today there are several solutions to meet the demand

for better fuel economy and one of them is the pneumatic hybrids. The idea with

pneumatic hybridization is to reduce the fuel consumption by taking advantage of the,

otherwise lost, brake energy.

In the work presented in this study a heavy duty Scania D12 engine has been converted

to work as a pneumatic hybrid. During... (More)
Urban traffic involves frequent acceleration and deceleration. During deceleration, the

energy previously used to accelerate the vehicle is mainly wasted on heat generated by

the friction brakes. If this energy that is wasted in traditional IC engines could be saved,

the fuel economy would improve. Today there are several solutions to meet the demand

for better fuel economy and one of them is the pneumatic hybrids. The idea with

pneumatic hybridization is to reduce the fuel consumption by taking advantage of the,

otherwise lost, brake energy.

In the work presented in this study a heavy duty Scania D12 engine has been converted

to work as a pneumatic hybrid. During pneumatic hybrid operation the engine can be

used as a 2‐stroke compressor for generation of compressed air during vehicle

deceleration (compressor mode) and during vehicle acceleration the engine can be

operated as an air‐motor driven by the previously stored pressurized air (air‐motor

mode). The compressed air is stored in a pressure tank connected to one of the inlet

ports. One of the engine inlet valves has been modified to work as a tank valve in order

to control the pressurized air flow to and from the pressure tank.

In order to switch between different modes of engine operation there is a need for a

fully variable valve actuation (FVVA) system. The engine used in this study is equipped

with pneumatic valve actuators that use compressed air in order to drive the valves and

the motion of the valves are controlled by a combination of electronics and hydraulics.

Since the pneumatic VVA system, used in the work presented in this thesis, was still

under development, the need to evaluate the system before any extensive use was more

than necessary.

The evaluation of the pneumatic VVA system verified its potential and a stable function

was noticed together with great flexibility to manipulate both valve timing and valve lift

to fit the desired purpose.

Initial testing concerning the different pneumatic hybrid engine modes of operation was

conducted. Both compressor mode (CM) and air‐motor mode (AM) were executed

successfully. Optimization of CM and AM with regards to valve timing and valve

geometry has been done with great improvements in regenerative efficiency which is

defined as the ratio between the energy extracted during AM and the energy consumed

during CM. (Less)
Please use this url to cite or link to this publication:
author
supervisor
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Compressor, Air-motor, Pneuamtc, Pneumatic-hybrid, VVT, Valve, regenerative, Hybrid, Air
pages
139 pages
publisher
Lund University (Media-Tryck)
language
English
LU publication?
yes
id
7a5a59a2-457c-4ba8-b9e4-9b98d85d0e44 (old id 1218737)
date added to LUP
2008-08-22 10:46:44
date last changed
2016-09-19 08:44:48
@misc{7a5a59a2-457c-4ba8-b9e4-9b98d85d0e44,
  abstract     = {Urban traffic involves frequent acceleration and deceleration. During deceleration, the<br/><br>
energy previously used to accelerate the vehicle is mainly wasted on heat generated by<br/><br>
the friction brakes. If this energy that is wasted in traditional IC engines could be saved,<br/><br>
the fuel economy would improve. Today there are several solutions to meet the demand<br/><br>
for better fuel economy and one of them is the pneumatic hybrids. The idea with<br/><br>
pneumatic hybridization is to reduce the fuel consumption by taking advantage of the,<br/><br>
otherwise lost, brake energy.<br/><br>
In the work presented in this study a heavy duty Scania D12 engine has been converted<br/><br>
to work as a pneumatic hybrid. During pneumatic hybrid operation the engine can be<br/><br>
used as a 2‐stroke compressor for generation of compressed air during vehicle<br/><br>
deceleration (compressor mode) and during vehicle acceleration the engine can be<br/><br>
operated as an air‐motor driven by the previously stored pressurized air (air‐motor<br/><br>
mode). The compressed air is stored in a pressure tank connected to one of the inlet<br/><br>
ports. One of the engine inlet valves has been modified to work as a tank valve in order<br/><br>
to control the pressurized air flow to and from the pressure tank.<br/><br>
In order to switch between different modes of engine operation there is a need for a<br/><br>
fully variable valve actuation (FVVA) system. The engine used in this study is equipped<br/><br>
with pneumatic valve actuators that use compressed air in order to drive the valves and<br/><br>
the motion of the valves are controlled by a combination of electronics and hydraulics.<br/><br>
Since the pneumatic VVA system, used in the work presented in this thesis, was still<br/><br>
under development, the need to evaluate the system before any extensive use was more<br/><br>
than necessary.<br/><br>
The evaluation of the pneumatic VVA system verified its potential and a stable function<br/><br>
was noticed together with great flexibility to manipulate both valve timing and valve lift<br/><br>
to fit the desired purpose.<br/><br>
Initial testing concerning the different pneumatic hybrid engine modes of operation was<br/><br>
conducted. Both compressor mode (CM) and air‐motor mode (AM) were executed<br/><br>
successfully. Optimization of CM and AM with regards to valve timing and valve<br/><br>
geometry has been done with great improvements in regenerative efficiency which is<br/><br>
defined as the ratio between the energy extracted during AM and the energy consumed<br/><br>
during CM.},
  author       = {Trajkovic, Sasa},
  keyword      = {Compressor,Air-motor,Pneuamtc,Pneumatic-hybrid,VVT,Valve,regenerative,Hybrid,Air},
  language     = {eng},
  note         = {Licentiate Thesis},
  pages        = {139},
  publisher    = {Lund University (Media-Tryck)},
  title        = {Study of a Pneumatic Hybrid aided by a FPGA Controlled Free Valve Technology System},
  year         = {2008},
}