DRAFT IMECE2007-43427 - Czech Technical University in Prague

Proceedings of IMECE07 

2007 ASME International Mechanical Engineering Congress and Exposition 

November 10-16, 2007, Seattle, Washington, USA 

DRAFT IMECE2007-43427 

1-D MODEL AND EXPERIMENTAL TESTS OF PRESSURE WAVE SUPERCHARGER 

Luděk Pohořelský 

Josef Božek Research Center 

Czech Technical University in Prague 

Technicka 4,CZ-166 07 Praha 6 

Phone +420 2 2435-2507 

Fax.+420 2 2435 2500 

Email :ludek.pohorelsky@fs.cvut.cz 

Jiří Vávra 


Czech Technical University in 

Prague 

Technicka 4,CZ-166 07 Praha 

6 

Phone +420 2 2435-1827 

Fax.+420 2 2435 2500 

Email :jiri.vavra@fs.cvut.cz 

ABSTRACT 

In this contribution an interesting boosting device, called 

pressure wave supercharger (PWS) according the wave 

phenomena inside it and taking advantage of speed of sound 

for air compression, is investigated both at diesel engine and at 

combustion chamber test bench using 1-D simulation and 

experimental measuring. Moreover, combustion engine 

supercharged by PWS has been compared using 1-D simulation 

to turbocharged one at steady state and transient operations. 

Pressure wave supercharger is simulated using detailed model 

based on the partial differential equations capturing non-linear 

effects of gas dynamics. The work has been performed using 

the commercial 1-D code GT-Power. Concept of modeling used 

enables to integrate the PWS model with all other models 

which are already created in the commercial codes (like more 

precise model of combustion, vehicle model, etc.) 

The PWS takes advantage of the direct pressure and enthalpy 

exchange between exhaust gases and fresh air in narrow 

channels to provide boost pressure. Due to the direct contact 

between exhaust gas and fresh air a mixing occurs. 

Nevertheless, this internal recirculation of exhaust gas can be 

used for lowering of NOx emissions, but in the same time it 

Philippe Obernesser 

RENAULT 

TCR GRA 085-1, avenue du Golf - 78288 

Guyancourt cedex, France 

tel: +33 1 76 85 30 70 

fax:+33 1 76 85 77 16 

Email : philippe.obernesser@renault.com 

Vojtěch Klír 





6 

Phone +420 2 2435-1855 

Fax.+420 2 2435 2500 

Email :vojtech.klir@fs.cvut.cz 

Jan Macek 





6 

Phone +420 2 2435-2504 

Fax.+420 2 2435 2500 

Email :jan.macek@fs.cvut.cz 

could deteriorate engine power as the result of a lack of 

oxygen. The internal mixing has been investigated using 1-D 

simulation and different possibilities to avoid mixing have been 

tested. The PWS has showed during the simulation work 

behavior it could fulfill demand on a modern car propulsion 

system. Finally PWS measurements with a combustion 

chamber have been undertaken and compared to the 1-D 

simulation results. Using the results of PWS measurement at 

the test bench and the 1-D simulation the usage of PWS in fuel 

cell applications is discussed, as well. 

This work is resulting from the collaboration between Josef 

Božek Research Center and Renault SA. 

Keywords: 1-D code simulation, pressure wave 

supercharger, diesel engine, test bench, flow characteristics, 

fuel cell 

INTRODUCTION 

Current research activities on new propulsion systems 

insist on the increase of their efficiency and power. On the 

other hand the stake consists in reducing the fuel consumption 

and the level of the pollutants produced by such new concepts. 

Lowering of emission of the green house gas CO2 forces 

1 Copyright © 2007 by ASME

manufactures to develop more economical vehicle and 

therefore more efficient engines. Moreover, in case of car 

propulsion systems the satisfactory driveability to satisfy 

driver’s demands during the accelerations has to be provided at 

the same time. An approach of utilization of downsized 

propulsion systems may lead successfully up to these aims. The 

main idea of downsizing is the reduction of the swept volume 

of the engine without lowering the original output power. The 

performance increase of the downsized engine to the same 

power level of the original one is achieved by boosting devices. 

Engine researchers and developers are nowadays wondering, 

which boosting devices are the most suitable and so are trying 

to find compromises with regards to costs, packaging, engine 

behavior and emission regulations. In addition to commonly 

utilized turbocharger mechanical superchargers as for instance 

Roots-type supercharger are more and more placed on the 

market. In comparison with these boosting devices the pressure 

wave supercharger (PWS) with usage of today’s control 

possibilities represents mainly in transient and low-end torque 

behavior an extraordinary possibility. The PWS takes 

advantages of a unique principle of direct pressure energy 

exchange between the exhaust gas and the fresh air in a narrow 

channel using nearly 1-D unsteady flow with a distinctive 

contact surface between the both gases. 

The idea of the energy exchange between two mediums without 

any separation goes down to the beginning of the 20 th century. 

Namely in its second decade, along the longitudinal axis 

perforated drum, a channeled rotor, has been patented by the 

German engineer Burghard - [24] - a machine delivering an 

uninterrupted mass flow of the pressurized air. As the unsteady 

flow theory, a necessity for the development of a usable 

machine has not been developed until the 1920’s and 1930’s, 

the Burghard’s invention did not succeed to an available 

device. 

In the 1940’s, the Brown Boveri (BBC, today ABB) 

turbocharger engineer Seippel designed a pressure exchanger 

as an air compressor of a gas turbine used as the propulsion of 

an experimental locomotive - [28]. He started to call this 

exchanger COMPREX according to the processes in the rotor – 

“compression-expansion”. 

In the 1950’s took place first experimental attempts in using 

COMPREX for supercharging of truck diesel engines - [12], 

[26], in framework of partnership among the ETH Zürich, the 

I-T-E Circuit Breaker Company, the BBC and the Saurer 

Company. 

In the 1970‘s, first experiments of COMPREX supercharged 

car diesel engines followed (partnership between BBC and 

Mercedes-Benz) – [30]. In 1979 BBC developed a race version 

of PWS for supercharging of F1 engine [10], which has been 

used only for the practice runs. In 1995, the Swissauto Wenko 

Company, which is dealing with development of pressure wave 

supercharger up to now - [19], designed for the environmental 

organization Greenpeace a so-called SmiLE car with SI engine 

with displacement of 360cm 3 and PWS supercharging – [20]. 

Moreover, in 1980’s many companies tested the COMPREX - 

supercharged diesel engines, but only two started the serial 

production. The Opel Company sold in a special Opel Senator 

set of about 700 units with 2.3l diesel engine and pressure 

wave supercharging – [31] whereas Mazda sold about 150 000 

COMPREX diesel passenger cars – [4]. 

Recently, several Universities (ETH Zürich, Indiana University 

Purdue University Indianapolis, Michigan State University, 

University of Tokyo, Warsaw University and Beijing 

University of Technology), companies (Swissauto Engineering 

S.A., Rolls Royce Alison) and governmental research centers 

(NASA) investigate pressure wave process intensively for 

various thermal applications. In [4] a comprehensive review of 

past and current research in developing of wave rotor 

technology is explained in more details and in a well arranged 

way. 

In framework of our study the PWS has been investigated and 

analyzed at first using 1-D diesel engine simulation. Then by 

means of experimental tests at the test bench to find out 

whether the pressure wave supercharging with regard to 

today’s state of art in control, actuation, materials and 

technology could fulfill requirements on a modern and 

perspective car propulsion system and become a serious 

competitor to current boosting systems. 

1-D SIMULATION OF PWS SUPERCHARGED DIESEL 

ENGINE 

For the study the Renault 1.5 diesel engine has been used 

for 1-D investigations to compare PWS supercharged engine to 

the turbocharged one. 

Stroke 80.5 mm 

Bore 76 mm 

Total swept volume 1461 cm3 

Number of cylinders 4 

Compression ratio 16:1 

Combustion system 2valves/cylinder 

Direct injection 

Table 1: Diesel engine parameters 

1-D model of PWS used, whose qualitative reaction to changes 

in design are in good agreement with published sources [1],[2] 

and with a simple model based on the theory of adiabatic shock 

waves and on the linear gas dynamics principles, has been 

created in commercial code GT-Power and is introduced and 

described in detail in [37]. 

Simulation of Full Load of Engine with PWS 

Diagrams in Figure 1-Figure 7 point out comparisons of 

PWS supercharged engines with turbocharged one. PWSs with 

unity length-to-diameter ratio of rotor (quadratic design) have 

been simulated. The PWS sucks more air into its channeled 

rotor than it compresses and delivers to the engine cylinder 

[25]. This fresh air scavenges and cools down the rotor and 


flows direct to the low pressure part of exhaust manifold PWS 

downstream. Therefore, the diameter of fresh air pipings and 

diameter of exhaust pipings PWS downstream have been 

enlarged in comparison to turbocharged engine. (In this study 

the diameter of particular pipings equals to 75% of PWS rotor 

diameter.) 

Air fuel ratio for PWS supercharged engines has been kept the 

same as for turbocharged engine. 

Proper function of PWS depends on the control geometry (i.e. 

location of inlet and outlet orifices at the air and exhaust 

flanges of PWS).Two different types of control geometry have 

been simulated: control geometry previously optimized by 

method of characteristics based on the linear gas dynamics [37] 

and patented geometry from Swissauto Engineering S.A. [7] 

The PWS speed has been optimized to reach maximum engine 

torque at each operation point. 

Boost pressure behavior is presented in Figure 1. The smaller 

the PWS the higher boost pressure can be achieved. The 

PWS70 (i.e. with rotor diameter and rotor length of 70 mm) 

achieves the highest boost pressure. The usage of the control 

geometry from Swissauto Company at PWS83 and PWS95 

increased the boost pressure significantly. 

Boost pressure [bar] 

3.2 

3 

2.8 

2.6 

2.4 

2.2 

2 

1.8 

1.6 

1.4 

1.2 

Boost pressure comparison 

PWS83 

PWS83_patented_Swissauto_geometry 

PWS70 

PWS95 

Turbo 


1 

1000 1500 2000 2500 3000 3500 4000 4500 

Engine speed [1/min] 

Figure 1: Comparison of PWS and turbocharger boost pressure 

In comparison to boost pressure, the engine torque (Figure 2) 

of PWS supercharged engines falls down at highest engine 

speeds. This is caused by internal exhaust gas recirculation 

(Figure 3) over the channeled rotor of PWS, which deteriorates 

the engine torque. Due to the direct contact of exhaust gas and 

fresh air, the exhaust gas can be delivered direct to the engine 

cylinder together with the compressed air. The smaller PWS the 

higher internal exhaust gas recirculation. 

Torque [N.m] 

260 

240 

220 

200 

180 

160 

Engine torque comparison 

140 

PWS83 


120 

PWS70 

PWS95 

100 

Turbo 

80 


1000 1500 2000 2500 3000 3500 4000 4500 


Figure 2: Comparison of engine torque 

Figure 4 presents the indicated specific fuel consumption. As 

the computation model of combustion for PWS supercharged 

engines was the same as in case of turbocharged engine (i.e. it 

did not take into account the increased amount of exhaust gas 

in the engine cylinder) the differences in indicated specific fuel 

consumption are given only by pumping work during the 

cylinder exchange. Figure 4 and Figure 5 demonstrate 

favorable behavior of the exhaust back pressure of the PWS 

supercharged engines. Up to the middle engine speed the boost 

pressure is distinctly higher than the back pressure. 

EGR [%] 

60 

50 

40 

30 

20 

10 

Exhaust gas recirculation into engine cylinder 

PWS83 


PWS70 

PWS95 


0 

1000 1500 2000 2500 3000 3500 4000 4500 


Figure 3: Exhaust gas recirculation into engine cylinder of 

PWS engines 

ISFC [g/kW/h] 

240 

230 

220 

210 

200 

190 

Idicated specific fuel consumption 

PWS83 


PWS70 

PWS95 

Turbo 


180 

1000 1500 2000 2500 3000 3500 4000 4500 


Figure 4: Comparison of indicated specific fuel consumption 


Pressure [bar] 

3.4 

3.2 

3 

2.8 

2.6 

2.4 

2.2 

2 

1.8 

1.6 

1.4 

1.2 

Boost pressure and exhaust back pressure 

Turbo-boost pressure 

PWS95_patented_Swissauto_geometry-boost pressure 

Turbo-back pressure 

PWS95_patented_Swissauto_geometry-back pressure 

1 

1000 1500 2000 2500 3000 3500 4000 4500 


Figure 5: Boost pressure and back pressure behavior 

PWS Speed 

Figure 6 shows the PWS speed characteristics. As the time 

of pressure wave propagation from exhaust to air side 

decreases with the reduction of the PWS size, the smallest 

PWS achieves the highest speeds. 

Diagrams on Figure 7 present dependences of the engine toque, 

boost pressure, indicated specific fuel consumption and the 

exhaust gas recirculation on the PWS speed. Each observed 

quantity achieves its optimum at a certain PWS speed. The 

increase of the PWS speed contributes to the lowering of the 

exhaust gas recirculation. 

PWS speed [1/min] 

15000 

14000 

13000 

12000 

11000 

10000 

9000 

PWS speed optimized for maximum engine torque 

PWS83 

PWS70 

PWS95 

8000 

1000 1500 2000 2500 3000 3500 4000 4500 


Figure 6: PWS speed characteristics 

Influence of PWS speed on engine parameters 

200 

1.9 

1.8 

1.7 

1.6 

1.5 

150 

1.4 

PWS83-engine torque 

1.3 

PWS83-boost pressure 

1.2 

1.1 

100 

1 

10000 11000 12000 13000 14000 15000 16000 


Engine torque [N.m] 


ISFC [g/kW/h] 

230 

225 

220 

215 

Influence of PWS speed on engine parameters 

PWS83-ISFC 

PWS83-EGR 

10000 11000 12000 13000 14000 15000 16000 


Figure 7: Dependence of engine parameters on PWS speed for 

engine speed of 1500rpm 

Variable Gas Pocket 

In order to extend the operating range of the PWS, so 

called pocket in the inner face of air and exhaust flanges have 

been patented by BBC in the 1960’s. Compression pocket, 

expansion pocket and gas pocket (Figure 8) by pass the gas 

between the channels and the control orifices and thus improve 

13 

11 

9 

7 

5 

3 

1 

EGR [%] 

the operation of the supercharger away from the optimum 

(tuned) point. Moreover, the gas pocket can be used in function 

of the waste-gate for control of the boost pressure. 

Variable Gas Pocket 

Exhaust inlet orifice 

Exhaust outlet orifice 

Exhaust 

Flange 

Channel 

Low-Pressure 

part 

Air inlet orifice 

Expansion Pocket 

Air outlet orifice 

High-Pressure 

part 

Compression 

Pocket 

Air Flange 

Figure 8: Pressure wave diagram and variable gas pocket in 

function of waste gate 

The variable gas pocket bypasses pressurized exhaust gas to the 

exhaust outlet via the rotor channel. The bypassed exhaust gas 

amplifies the expansion wave in the low-pressure part, which 

provides better fresh air suction into channeled rotor. 

The function and efficiency of the variable gas pocket have 

been confirmed by means of the simulation. Simulation results 

presented in Figure 1-Figure 7 show turbocharger controlled by 

the variable turbine geometry, whereas the boost pressure of 

PWS has not been controlled. 

Diagrams on Figure 9 show results of boost pressure control 

for PWS95 with the variable gas pocket at highest engine 

speeds (Figure 9 left). Moreover, utilization of the variable gas 

pocket for boost pressure control contributes to the lowering of 

the internal exhaust gas recirculation (Figure 9 right). 


2.9 

2.8 

2.7 

2.6 

2.5 

Boost pressure control by variable gas pocket 

PWS95 w/o VGP control 

PWS with VGP 

2.4 

3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 


Influence of gas pocket control on the internal gas 

recirculation 

20 

19 

18 

17 

16 

PWS95 w/o VGP control 

15 

14 

13 

12 

PWS with VGP 

3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 

EGR [%] 


Figure 9: Influence of variable gas pocket control (VGP) on 

the boost pressure and internal exhaust gas recirculation 

Influence of Flow Losses 

Figure 10 describes influence of flow losses on the PWS 

behavior. Flow losses have been increased by changing inlet 

(Air inlet orifice upstream -Figure 8) and outlet (Exhaust outlet 

orifice downstream -Figure 8) pipings diameters from 75% to 

40% of PWS rotor diameter. 

From the 1-D simulation follows that to throttle the air inlet and 

exhaust outlet of PWS deteriorates scavenging of the PWS 


otor by increasing internal exhaust gas recirculation, and 

consequently lowers engine torque considerably. 

Torque [N.m] 

230 

210 

190 

170 

150 

130 

110 

90 

Engine torque comparison 

70 

PWS83_pipings with diameter of 75% of PWS rotor diameter 

50 PWS83_pipings with diameter of 50% of PWS rotor diameter 

30 

PWS83_pipings with diameter of 40% of PWS rotor diameter 

1000 1500 2000 2500 3000 3500 4000 4500 


Figure 10: Influence of flow losses on the PWS engine torque 

Transient Simulation of Engine with PWS 

To investigate the transient response of PWS 

supercharged engine the engine torque vary from the low load 

to full load at a constant engine speed. The load of engine was 

defined to be equal to the instantaneous engine torque, which 

prevents speed changes. Since the engine torque rises during 

the load step faster than the engine speed, this test of dynamic 

behavior corresponds to the first instant of vehicle acceleration. 


1.8 

1.7 

1.6 

1.5 

1.4 

1.3 

1.2 

1.1 

Boost pressure response 

PWS83 

Turbo 

1 

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 

Time [sec] 

Figure 11: Boost pressure response for 1.5 diesel engine with 

PWS83 at engine speed of 1250 rpm 

The PWS boost pressure increases steeper than the 

turbocharger one (Figure 11). During the load step an increased 

internal exhaust gas recirculation appears (Figure 13), this is 

the reason of the decreasing delay at the middle of the load step 

between the PWS supercharged and turbocharged engine 

(Figure 12). 


200 

180 

160 

140 

120 

100 

80 

60 

40 

20 

Engine torque response 

PWS83 

Turbo 

0 

1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 

Time [sec] 

Figure 12: Torque response for 1.5 diesel engine with PWS83 

at engine speed of 1250 rpm 

EGR [%] 

26 

21 

16 

11 

6 

Internal exhasut gas recirculation during transient 

PWS83 

1 

1.5 2.0 2.5 3.0 3.5 4.0 

Time [sec] 

Figure 13: Internal exhaust gas recirculation in transient 

operation 

During the simulation of spark-ignited engine, presented in 

[38], more considerable deterioration of engine torque appeared 

than in case of 1.5 diesel engine. Change of PWS speed 

(Figure 14 right) during the transient operation was an efficient 

remedy to improve engine torque behavior (Figure 14 left) and 

to decrease the internal exhaust gas recirculation in transient 

operation. 


200 

150 

100 

50 

0 

1.2 SI Engine torque response 

PWS83_constant_speed 

Turbo 

PWS83_with_speed_control 

1 1.5 2 2.5 3 3.5 4 4.5 5 

Time [s] 

PWS speed [rpm] 

PWS speed control during the load step 

19000 

18000 

17000 

16000 

15000 

14000 

13000 

12000 

1 1.5 2 2.5 3 3.5 4 4.5 5 

Time [s] 

Figure 14: Engine torque and its remedy during the load step 

of spark ignited 1.2l engine at engine speed of 2000rpm from 

[38] 

EXPERIMENTAL TESTS ON PWS 

For the engine 1-D simulation, presented in this paper, a 

PWS model has been used, whose physical behavior was 

representative enough. From the 1-D engine simulation a 

favorable PWS low end torque behavior and transient response 

arise. Moreover, the PWS could be with advantage used for 

control of quantity of recycled exhaust gas to combustion 

engine. However, the internal exhaust gas recirculation, boost 

pressure and mass flow value should be checked and settled to 

enable the model. Therefore, to keep developing 1-D model of 

supercharging system with PWS the PWS operating points 

have been tested and measured at the combustion chamber test 

bench with open circuit (Figure 15). The specimen of tested 

PWS was model CX93 used by Mazda Company for 

supercharging of 2.0l diesel engine [27]. 

In framework of experimental testing of PWS the mass flow 

range at PWS air inlet (AI), air outlet (AO) and exhaust inlet 

(EI), the PWS speed range and range of the PWS exhaust inlet 

(EI) temperature have been largely explored. 


Electrical motor 

Mass flow control 

m2 

(0 to 200g/s) 

p2 

T2 

(RPMc from 0 to 20000) 

p1 

m2, C 

AO 

AI 

m1 

p1 pressure control (1 to 3b) 

Tatm 

Noise 

Figure 15: Scheme of the test bed 

p3 T3 

EI 

EO 

Mass flow control 

m3 

(0 to 200g/s) 

p4 

m3, C 

Backpressure 

floodgate 

p4 pressure control (1 to 3 b) 

The PWS test bench has been created using the existing 

turbocharger test bench (equipped with the combustion 

chamber and the external source of constant boost air pressure 

of 350 kPa and mass flow up to approximately 1000 kg/h) and 

its adopting for PWS tests at Josef Božek Research Center 

(JBRC) - Figure 16. 

AI 

Figure 16: PWS at the combustion chamber test bed 

Mass flow and temperature have been enforced at the exhaust 

inlet (EI). EI mass flow was continuous and has been varied 

between 0-200 g/s. Air outlet (AO) and exhaust inlet (EI) mass 

flows have been controlled separately by means of remotely 

controlled slide valves enabling precise tuning of flows. Mass 

flow at air outlet (AO) has been controlled at the same value as 

that of exhaust inlet (EI). The temperature has been scanned 

from 800K to 1050K at exhaust inlet. 

Measuring of EI and AO mass flows has been performed using 

metering orifices in pipelines. AI mass flow has been measured 

using intake nozzle. 

EI 

AO 

EO 

All temperature measurements have been carried out by 

electrically isolated thermocouples. The most problematic 

temperature measurement was the temperature T3 at EI after the 

combustion chamber. Therefore, five thermocouples have been 

utilized to obtain the temperature distribution within the 

manifold. 

To estimate the internal exhaust gas recirculation of PWS molar 

fractions of CO2 at EI and AO have been measured by means of 

exhaust gas analyzer. 

The PWS has been driven directly by electrical motor, whose 

speed has been controlled by frequency converter and could 

vary between 0-20000 rpm. The PWS speed has been measured 

using optical sensor. As the PWS had to be braked in specific 

operation regimes, the brake resistors had to be additionally 

connected to the frequency converter. 

In framework of this project a new automated data acquisition 

system has been developed under the Testpoint development 

environment, which enabled to display all instant measured 

values and control panel with diagrams showing their trends 

(Figure 17). 

DAQ Control Panel 

with time history 

diagram for settling 

identification 

Gas analyzer 

display 

Figure 17: Displays of measured values and DAQ software 

control panel with time history diagrams. 

Performance maps of measured PWS 

Diagrams on Figure 18-Figure 23 show performance maps for 

exhaust inlet temperature of 900K. The total PWS efficiency, 

AO temperature, internal exhaust gas recirculation, air inlet 

mass flow and electrical input to PWS are depicted legible in 

form commonly used for turbochargers, so these maps can be 

with advantage used for direct comparison to turbochargers 

maps. 

From the flow characteristics diagram on Figure 18 the 

influence of PWS speed on boost pressure ratio is clearly 

visible. For PWS speed from 14000 rpm to 18000 rpm the 

highest PWS total efficiencies are achieved (Figure 19). 

Lowering of the PWS speed decreases the PWS efficiency and 

increases the boost pressure (Figure 18). From a certain mass 

flow, here for mass flow higher than 550kg/h, the PWS boost 

pressure ratio falls abruptly down. 


Figure 18: PWS performance map of PWS speed for EI 

temperature of 900K 

Internal exhaust gas recirculation over the channeled rotor is 

presented in Figure 20. In the PWS speed range from 

10000rpm to 20000rpm no recirculation appears up to the mass 

flow of 400kg/h. 

The AO temperatures traces are shown in Figure 21. Up to the 

PWS speed of 16000 rpm the increase of PWS speed decreases 

the AO temperature. AO temperature starts to rise significantly 

bellow the PWS speed of 10000 rpm. 

The PWS sucks in AI much more fresh air than it delivers to 

the air outlet. Amount of sucked fresh air increases with the 

increase of the AO mass flow (Figure 22) whereas for the EI 

mass flows from 400 to 650 kg/h there is no considerable 

difference between the sucked amounts of fresh air into PWS. 

The diagram on Figure 23 presents power input to the electrical 

motor, which drives the PWS. The negative sign of the power 

input means that the PWS drives the el. motor. 

Figure 19: PWS performance map of PWS total efficiency for 

EI temperature of 900K 

Figure 20: PWS performance map of internal exhaust gas 

recirculation for EI temperature of 900K 

Figure 21: PWS performance map of air outlet (AO) 

temperature for EI temperature of 900K 

Figure 22: PWS performance map for air inlet mass flow for 

EI temperature of 900K 


Figure 23: PWS performance map for electrical power 

input/output of PWS for temperature of 900K 

Influence of the temperature at PWS exhaust inlet 

Diagrams in Figure 24-Figure 27 present influence of the 

EI temperature for four different levels of EI pressure p3 (1.5, 

2, 2.5 and 3 bar - absolute). The PWS operation points have 

been measured for EI temperature of 800K, 900K and 1050K. 

The increase of the EI temperature increases the boost pressure. 

The highest EI temperature of 1050K extended the range where 

the boost pressure is higher than the back pressure p3 (Figure 

24). 

p2 [kPa] 

200 

150 

100 

50 

Relative pressures 

0 

0 5000 10000 15000 20000 25000 


p3=50kPa T3=800K p3=100kPa T3=800K p3=150kPa T3=800K p3=200kPa T3=800K 



Figure 24: Boost pressure in dependence on the EI temperature 

m3 [kg/h] 

700 

600 

500 

400 

300 

200 

100 

0 

0 5000 10000 15000 20000 25000 





Figure 25: EI mass flow in dependence on the EI temperature 

A lower EI mass flow is necessary with EI temperature increase 

to achieve the same EI pressure (Figure 25). The increase in EI 

temperature decreases the internal exhaust gas recirculation 

(Figure 26) and deteriorates the PWS efficiency (Figure 27). 

egr [1] 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

0 5000 10000 15000 20000 25000 





Figure 26: Internal exhaust gas recirculation in dependence on 

EI temperature 

etaPWS [1] 

0.5 

0.4 

0.3 

0.2 

0 5000 10000 15000 20000 25000 


p3=100kPa T3=800K p3=100kPa T3=900K p3=100kPa T3=1050K 

Figure 27: Total efficiency of PWS in dependence on EI 

temperature 

Influence of Flow Losses in Air Inlet 

The influence of the flow losses in AI has been 

investigated at EI temperature of 900K and PWS speed of 

15000 rpm for two orifice plates with diameters of 35 mm and 

50 mm (origin AI manifold diameter of 100 mm). 

The orifice with diameter 35 mm deteriorates the boost 

pressure significantly above the mass flow of 400 kg/h. The 

throttling of the AI mass flow increases the AO and EO 

temperatures and the internal exhaust gas recirculation. On the 

other hand, the reduction of the AI mass flow improves the 

PWS efficiency at low EI mass flow rates (Figure 29 left). 

All diagrams described in above paragraphs have been 

measured without boost pressure control using waste gate 

(WG). Diagrams in Figure 28 and Figure 29 show influence of 

waste gate control on PWS operation, as well. The waste gate 

trims the boost pressure and tries to keep it approx. constant 

(Figure 28 left). The waste gate does not influence the internal 

exhaust gas recirculation (Figure 29 right). 


πC [1] 

2.60 

2.40 

2.20 

2.00 

1.80 

1.60 

1.40 

1.20 

1.00 

dia 35 mm 

dia 50 mm 

WG 

w / o Loss 

0 100 200 300 400 500 600 700 

m 2red [kg/h] 

p1 [kPa] 

9 

8 

7 

6 

5 

4 

dia 35 mm 

3 

2 

1 

dia 50 mm 

0 100 200 300 400 

m3 [kg/h] 

500 600 700 

Figure 28: Influence of pressure losses (right) and waste gate 

on pressure ratio in dependence on reduced AO mass flow 

etaPWS [1] 

0.50 

0.45 

0.40 

0.35 

0.30 

0.25 

0.20 

dia 35 mm 

0.15 

dia 50 mm 

0.10 

0.05 

0.00 

WG 

w / o Loss 

0 100 200 300 400 500 600 700 

m2, m3 [kg/h] 

egr [1] 

0.35 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

0.00 

dia 35 mm 

dia 50 mm 

WG 

w / o Loss 

0 100 200 300 400 500 600 700 

m2, m3 [kg/h] 

Figure 29: Influence of pressure losses in AI manifold on PWS 

efficiency and internal egr 

Influence of Flow Losses in Exhaust Outlet 

The EO pressure has been increased using throttle which has 

been controlled by stepper electric motor. A snail gear box has 

been placed between the throttle and the electrical motor to 

prevent throttle flapping by EO flow. 

PWS 

EO 

Flow losses 

Figure 30: EO throttle controlled by stepper electrical motor 

with snail box 

Diagrams in Figure 31 and Figure 32 present the sensitivity of 

the PWS on the EO pressure for EI mass flows of (100,300,400 

and 500) kg/h and for EI temperature of 900K. The PWS speed 

has been kept at 15 000rpm. The change in EO pressure by 

2kPa deteriorates the boost pressure significantly (Figure 31). 

The increased EO pressure lowers the amount of sucked AI 

mass flow and increases the internal exhaust gas recirculation 

rises (Figure 32). 

Moreover, increased EO pressure may cause the back flow of 

the exhaust gas to the AI. 

Relative pressure p2 [kPa] 

140 

120 

100 

80 

60 

40 

20 

100kg/h 300kg/h 400kg/h 500kg/h 

0 

95.5 96 96.5 97 97.5 98 98.5 99 99.5 

Absolute pressure p4 [kPa] 

Figure 31: Influence of the EO pressure on the boost pressure 

egr [1] 

0.45 

0.4 

0.35 

0.3 

0.25 

0.2 

0.15 

0.1 

0.05 

100kg/h 300kg/h 400kg/h 500kg/h 

0 

95.5 96 96.5 97 97.5 98 98.5 99 99.5 

Absolute pressure p4 [kPa] 

Figure 32: Influence of the EO pressure on the AI mass flow 

Supercharging of the PWS 

In framework of the measurement the feasibility of the 

PWS for the two stage supercharging has been investigated. 

To enable pressure increase in AI the test bench has been 

equipped with inlet pipeline of pressurized air (Figure 33). 

External source could deliver constant boost air pressure of 

350kPa and mass flow approx. of 1000kg/h into AI. AI mass 

flow has been controlled using slide valve, which has been 

actuated by an electric stepper motor. Moreover, metering 

orifice has been placed into the AI pipeline. 

The measurement has been performed for EI mass flow of 300 

kg/h and for two different PWS speeds of 15000 rpm (Figure 

34) and 10000 rpm (Figure 35). As in the all previous 

paragraphs the mass flow at air outlet (AO) has been controlled 

at the same value as that of exhaust inlet (EI). The EI 

temperature has been kept at 900K. For the fully opened EO 

throttle (Figure 30) the air inlet mass flow has been set to be 

the same as the naturally aspirated mass flow for this PWS 

operation point. By adjusting of the EO throttle the EO and AI 

pressures have been increased. 


Figure 33: Supercharging of PWS 

The boost pressure and EI pressure rise with the AI pressure 

increase both for 10000 rpm and 15000rpm (Figure 34 and 

Figure 35 left).The boost pressure increases by the same value 

as that set at AI. 

The AI mass flow did not change with the AI pressure increase 

(Figure 34 and Figure 35 right). No internal exhaust gas 

recirculation appeared at both cases. 

180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

Relative pressures [kPa] 

PWS Supercharging 

15 000 rpm, m2=m3=300 kg/h, T3=900K 

p2_300 

p3_300 

p4_300 

0 10 20 30 40 50 60 70 


m1, m2, m3 [kg/h] 

580 

530 

480 

430 

380 

330 

280 

230 

180 

Mass flows 

m1 

m2 

m3 

0 10 20 30 40 50 60 70 


Figure 34: Influence of AI pressure on AO, EI and EO 

pressures and on AI mass flow for PWS speed of 15000 rpm 

Relative pressures [kPa] 

250 

200 

150 

100 

50 

0 

Pipeline of pressurized 

air to PWS air inlet 

PWS Supercharging 

10 000 rpm, m2=m3=300 kg/h, T3=900K 

p2_300 

p3_300 

p4_300 

0 20 40 60 80 100 120 


m1, m2, m3 [kg/h] 

580 

530 

480 

430 

380 

330 

280 

230 

180 

Mass flows 

m1 

m2 

m3 

0 20 40 60 80 100 120 


Figure 35: Influence of AI pressure on AO, EI and EO 

pressures and on AI mass flow for PWS speed of 10000 rpm 

COMPARISON OF 1-D MODEL SIMULATION TO 

MEASUREMENT 

To compare the simulation results to measurements a 1-D 

model of the tested PWS at the test bench has been developped 

in GT-Power, whereas the PWS without pockets has been 

simulated. Analogous to experiment the mass flow at air outlet 

(AO in Figure 15) has been controlled at the same value as that 

of exhaust inlet (EI). 

Diagrams on Figure 36 and Figure 37 present comparison of 

boost pressure p2, back pressure p3, air inlet mass flow and 

internal exhaust gas recirculation for constant exhaust inlet 

mass flow of 300kg/h. (In Annex A the same comparison is 

shown for EI mass flows of 100kg/h, 400kg/h and 500kg/h.) 

The 1-D model predicts maximal boost pressure higher than the 

measured one (Figure 36). The simulated difference between 

boost pressure and back pressure is higher and in larger PWS 

speed range than measured one. 1-D PWS model recirculates 

more exhaust gas than the real PWS (Figure 37 right). 

Boost and back pressure comparison 

2.50 

2.40 

2.30 

2.20 

2.10 

2.00 

1.90 

1.80 

1.70 

1.60 

1.50 

1.40 

1.30 

1.20 

1.10 

1.00 

0 5000 10000 15000 20000 


p2-300kg/h-measured p3-300kg/h measured 

p2-300kg/h 1-D model without pockets p3-300kg/h 1-D model without pockets 

Absolute pressure [bar] 

Figure 36: Comparison of measured and computed pressures 

for EI mass flow of 300kg/h 

Mass flow comparison 

160 

140 

120 

100 

80 

60 

40 

20 

0 

0 5000 10000 15000 20000 


m1-300kg/h-measured m1-300kg/h 1-D model without pockets 

m2-300kg/h 1-D model without pockets m3-300kg/h 1-D model without pockets 

Mass flow [g/sec] 

EGR [1] 

Internal exhaust gas recirculation 

0.4 

0.35 

0.3 

0.25 

0.2 

0.15 

0.1 

0.05 

0 

0 5000 10000 15000 20000 


egr-300kg/h-measured egr-300kg/h 1-D model without pockets 

Figure 37: Comparison of measured and computed AI mass 

flow and internal exhaust gas recirculation for EI mass flow of 

300kg/h 

Diagrams on Figure 38 - Figure 41 compare 1-D simulation 

results for three different EI temperatures (800K, 900K and 

1050K) and for constant EI pressure of 2 barAbsolute. The 

qualitative reaction of the 1-D model on EI temperature change 

is in a good agreement with the measurement for every 

observed quantity. The boost pressure increases with the EI 

temperature. The maximal simulated boost pressure is for every 

temperature higher than the EI pressure (Figure 38). An 

increase of EI temperature increases the amount of fresh air 

which is sucked into the PWS (Figure 40) and decreases the 

internal exhaust gas recirculation (Figure 41). 

p2 [bar] 

2.40 

2.30 

2.20 

2.10 

2.00 

1.90 

1.80 

1.70 

1.60 

1.50 

Absolute boost pressure 

for absolute back pressure of p3=2bar 

0 5000 10000 


15000 20000 

p3=2bar T3=800K measured p3=2bar T3=900K measured 

p3=2bar T3=1050K measured p3=2bar T3=800K 1-D model w/o pockets 

p3=2bar T3=900K 1-D model w/o pockets p3=2bar T3=1050K 1-D model w/o pockets 

Figure 38: Comparison of measured and computed boost 

pressures for tree different EI temperatures and constant EI 

absolute pressure of 2bar 


m2 [g/s] 

110 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Air outlet mass flow 


p3=2bar T3=800K measured 



p3=2bar T3=800K 1D model w/o pockets 



0 5000 10000 


15000 20000 

Figure 39: Comparison of measured and computed air outlet 

mass flows for tree different EI temperatures and constant EI 

pressure of 2bar 

m1 [g/s] 

160 

140 

120 

100 

80 

Air inlet mass flow 


60 

0 5000 10000 


15000 20000 


p3=2bar T3=1050K measured p3=2bar T3=800K 1D model w/o pockets 

p3=2bar T3=900K 1D model w/o pockets p3=2bar T3=1050K 1D model w/o pocktes 

Figure 40: Comparison of measured and computed air inlet 

mass flows for tree different EI temperatures and constant EI 

absolute pressure of 2bar 

EGR [%] 

0.30 

0.20 

0.10 

Internal exhaust gas recirculation 


0.00 

0 5000 10000 


15000 20000 


p3=2bar T3=1050K measured p3=2bar T3=800K 1D model w/o pockets 

p3=2bar T3=900K 1D model w/o pockets p3=2bar T3=1050K 1D model w/o pockets 

Figure 41: Comparison of measured and computed internal 

exhaust gas recirculations for tree different EI temperatures and 

constant EI absolute pressure of 2bar 

PWS model with all pockets has been simulated, as well (see 

diagrams on Figure 42 and Figure 43). Pockets extended the 

working range of the PWS model. Nevertheless, the modeled 

pockets increased the boost pressure in low PWS speed too 

much in comparison to measurement. 


3.5 

3 

2.5 

2 

1.5 

1 

Absolute pressure comparison 

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 


p3-300kg/h with pockets p2-300kg/h with pockets 

p2-300kg/h-measured p3-300kg/h-measured 

p2-300kg/h without pockets p3-300kg/h without pockets 

Figure 42: Comparison of measured and computed pressures 

for EI mass flow of 300kg/h and 1-D PWS model with pockets 



160 

140 

120 

100 

80 

60 

40 

m3-300kg/h with pockets m2-300kg/h with pockets 

20 

0 

m1-300kg/h with pockets 

m1-300kg/h without pockets 

m1-300kg/h-measured 

0 5000 10000 


15000 20000 

EGR [1] 

EGR comparison 

1 

0.9 

egr-300kg/h with pockets egr-300kg/h-measured 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

egr-300kg/h without pockets 

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 


Figure 43: Comparison of measured and computed AI mass 

flow and internal exhaust gas recirculation for EI mass flow of 

300kg/h and 1-D PWS model with pockets 

Presented and described comparisons in diagrams above 

indicate that the flow losses in the 1-D model of PWS rotor 

channel should be tuned with regard to pressure traces to come 

closer to the measurement. Following paragraph discusses the 

problematic of increased simulated exhaust gas recirculation in 

comparison to measurement. 

In the channel of the PWS rotor the fresh air and exhaust gas 

are in direct contact. GT-Power is based on the finite volume 

method. Thus, the 1-D model is discretized into many volumes 

and the solution is carried out by time integration of equations 

of continuity, energy and momentum. Finer discretization 

results in better accuracy and extends the computation time 

vice versa. 

Diagrams in Figure 44 and Figure 45 show influence of the 

discretization length on the simulated results. The influence has 

been investigated for constant mass flow of 300kg/h and EI 

temperature of 900K. By lowering of the dicretization length 

by one third of the original length (here to 5mm) the internal 

exhaust gas recirculation decreased by 10% (Figure 45) and the 

simulated boost pressure increased by 5%. At the same time the 

computation time has been 1.8 times longer than the original 

one. 


2.50 

2.40 

2.30 

2.20 

2.10 

2.00 

1.90 

1.80 

1.70 

1.60 

1.50 

1.40 

1.30 

1.20 

1.10 

1.00 



p2-300kg/h-measured 

p3-300kg/h measured 

p2-300kg/h 1-D model without pockets 

p3-300kg/h 1-D model without pockets 

p2-300kg/h 1-D model without pockets with dx=5mm 

p3-300kg/h 1-D model without pockets with dx=5mm 

0 5000 10000 15000 20000 


Figure 44: Influence of discretization length of PWS rotor 

channel on pressure traces 



160 

140 

120 

100 

80 

60 


40 

m1-300kg/h 1-D model without pockets 


20 


0 

m1-300kg/h 1-D model without pockets with dx=5mm 

0 5000 10000 


15000 20000 

0.5 

0.45 

0.4 

0.35 

0.3 

0.25 

0.2 

0.15 

0.1 

0.05 

0 

EGR [1] 


egr-300kg/h-measured 

egr-300kg/h 1-D model without pockets 

egr-300kg/h 1-D model without pockets with dx=5mm 

5000 7000 9000 11000 13000 15000 17000 19000 


Figure 45: Influence of discretization length of PWS rotor 

channel on computed mass flow and internal exhaust gas 

recirculation 

PWS IN FUEL CELL APPLICATIONS 

Fuel cells are among the most promising alternative 

energy sources of the future with regard to clean and efficient 

power generation [33]. Hydrogen reacts with oxygen producing 

water, electric current and heat. Running of the fuel cell at 

higher pressure increases the power due to the polarization 

curve improvement [32], [35] and reduces the cell dimensions. 

Therefore, the fuel cells of 10kW or more utilize boosting 

device for air compression to increase oxygen partial pressure 

[32]. As the flow through the fuel cell can be described as the 

flow through a throttle the boost pressure has to be higher than 

the back pressure. The proton exchange membrane (PEM) fuel 

cell, the most preferred fuel cell type for automotive systems, 

must have sufficient water content in the polymer electrolyte 

and the humidity of the air must be carefully controlled [32]. 

From the combustion chamber measurement of the tested PWS 

model CX93 follows (Figure 24) that its boost pressure is 

higher than the back pressure for EI temperature higher than 

900K. This makes a burner PWS upstream necessary to have 

enough energy for air compression. Due to the direct contact of 

air and vapor in the rotor channel, the PWS could be of 

advantage if used for air humidification realized by throttling at 

AI of PWS (Figure 29). 

Using the 1-D simulation the PWS93 with in [7] patented 

geometry, which provided significantly increased boost 

pressure (Figure 1), has been computed at the test bench for 

back pressure of 2barAbsolute and EI temperatures of 150°C and 

500°C. From the diagrams (Figure 46 and Figure 47) is visible 

that at the lower temperature of 150°C the PWS is unsuitable 

for full cell applications. At the temperature of 500°C the boost 

pressure surpass the back pressure. Another way of using PWS 

for this purpose would be a combination with serial connected, 

electric driven, compressor, which is necessary as a starter in 

any case. 

Absolute boost pressure for absolute back pressure 

of 2bar 

2.2 

2.1 

2 

1.9 

1.8 

1.7 

1.6 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

6000 6500 7000 7500 8000 


8500 9000 9500 10000 

Absolute pressure p2 [bar] 

p3=2bar T3=150degC 1-D model without pockets 


Figure 46: Computed boost pressure for back pressure of 2bar 

and two different temperatures 

Air outlet mass flow for absolute back pressure of 

2bar 

131 

121 

111 

101 

91 

81 

71 

61 

51 

41 

31 

21 

11 

1 

6000 6500 7000 7500 8000 


8500 9000 9500 10000 

AO mass flow m2 [g/sec] 



Figure 47: Computed air outlet mass flow for back pressure of 

2bar and two different temperatures 

CONCLUSIONS 

In framework of the study presented in this paper the 

pressure wave supercharger (PWS) has been investigated using 

1-D engine simulation and experimental measurement at the 

combustion chamber test bench. 

1-D simulation of different PWS sizes contributed to 

understanding of PWS behavior in engine application. The 

PWS has higher boost pressure at low engine speeds than the 

turbocharger. Using the variable transmission ratio between the 

PWS and the engine the boost pressure can be hold on high 

level over the whole engine speed range. Whereas the engine 

speed increases the scavenging of the PWS rotor decreases. At 

the highest engine speeds the internal exhaust gas recirculation 

rises and deteriorates the engine power. The variable gas pocket 

improves the rotor scavenging and can be with advantage used 

for boost pressure control. During the transient operation the 

increased internal exhaust gas recirculation appeared. Change 

of PWS speed during the load step improved transient 

behavior. 

The PWS has been largely explored at the combustion chamber 

test bench and performance maps of measured PWS created. 

The measurement showed high sensitivity of PWS on flow 

losses mainly in exhaust outlet. Pressure increase in air inlet of 

PWS increases the boost pressure by the same pressure. 


The 1-D model of PWS at the test bench has been created to 

compare simulation to experiment. The established database of 

measured data creates very good basis for further 1-D model 

calibration. The qualitative reaction of PWS model is in a very 

good agreement with the measurement. The 1-D model predicts 

higher difference between boost pressure and back pressure and 

in larger PWS speed range than measurements. In next steps 

mainly the flow losses in the model should be tuned to calibrate 

the model. 

Utilization of the PWS in the fuel cell application makes a 

burner PWS upstream necessary. 1-D model and measured 

database could be with advantage used for further 

investigations on this topic. 

NOMENCLATURE 

AI Air inlet 

AO Air outlet 

C Molar fraction of CO2 

EI Exhaust inlet 

EO Exhaust outlet 

etaPWS Total efficiency of PWS 

ISFC Indicated specific fuel consumption [g/kW/h] 

m1 Mass flow in AI [kg/h] 

m2 Mass flow in AO [kg/h] 

m2red Reduced air mass flow in AO [kg/h] 

m3 Air mass flow in EI [kg/h] 

p0 Ambient pressure [kPa] 

p2 Relative boost pressure [kPa] 

p3 Relative EI pressure [kPa] 

p4 Relative EO pressure [kPa] 

piC Pressure ratio [1] 

PWS Pressure wave supercharger 

t0 Ambient temperature 

t1 Inlet temperature [deg C] 

t2 AO temperature [deg C] 

t3 EI average temperature [deg C] 

t4 EO temperature [deg C] 

ACKNOWLEDGMENTS 

The authors would like to express their grateful thanks to 

Czech turbocharger maker ČZ a.s., division Turbo, namely to 

Mr. Stulík, Mr. Havelka, Mr. Mach and division director Mr. 

Pinkas for fruitful cooperation and support throughout the 

project. Special thank belongs to prof. Takats from JBRC for 

his kindly help with taking CO2 measurement into operation. 

Additional thanks belong also to author’s colleges from JBRC 

prof. Uhlíř and prof. Novák for their kind help with taking of 

PWS electric drive into operation. 

. 

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Automotive Powertrains” 




1.7 

1.6 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

0 5000 10000 15000 20000 


p2-100kg/h-measured p3-100kg/h-measured 


Figure A1: 1-D simulation vs. measurement 

for constant EI mass flow of 100kg/h 

1.9 

1.8 

1.7 

1.6 

1.5 

1.4 

1.3 

1.2 

1.1 

1 

2 

2.9 

2.8 

2.7 

2.6 

2.5 

2.4 

2.3 

2.2 

2.1 

3 

3.1 



6000 8000 10000 12000 14000 16000 18000 20000 





ANNEX A 

COMPARISON OF 1-D MODEL SIMULATION TO MEASUREMENT 

Figure A2: 1-D simulation vs. measurement for constant 

EI mass flow of 400kg/h 

1.9 

1.8 

1.7 

1.6 

1.5 

2 

2.9 

2.8 

2.7 

2.6 

2.5 

2.4 

2.3 

2.2 

2.1 

3 

3.5 

3.4 

3.3 

3.2 

3.1 



6000 8000 10000 12000 14000 16000 18000 20000 





Figure A3: 1-D simulation vs. measurement for constant EI 

mass flow of 500kg/h 




120 

0.2 

0.18 

100 

0.16 

80 

0.14 

0.12 

60 

0.1 

40 

0.08 

0.06 

20 

0.04 

0 

0.02 

0 5000 10000 15000 20000 

0 


0 5000 10000 15000 20000 

m1-100kg/h-measured m1-100kg/h 1-D model without pockets 



egr-100kg/h-measured egr-400kg/h 1-D model without pockets 


180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

6000 8000 10000 12000 14000 16000 18000 20000 







180 

160 

140 

120 

100 

80 

60 

40 

20 

0 

6000 8000 10000 12000 14000 16000 18000 20000 






EGR [1] 


0.50 

0.45 

0.40 

0.35 

0.30 

0.25 

0.20 

0.15 

0.10 

0.05 

0.00 

6000 8000 10000 12000 14000 16000 18000 20000 


egr-400kg/h-measured p2-400kg/h 1-D model without pockets 

EGR [1] 

EGR [1] 


0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0 

6000 8000 10000 12000 14000 16000 18000 20000 


500kg/h-measured 500kg/h 1-D model without pockets

DRAFT IMECE2007-43427 - Czech Technical University in Prague

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