flat4 - emission technology

Introduction

Mounting at VW Flat4 Engines

Catalytic Converters - Market Overview (Germany)

European Emission Limits

Developments in Unleaded Fuels

Introduction
A catalytic converter is a device used in automobiles to reduce the amount of pollutants in it’s exhaust. Catalytic converters are catalysts that encourage chemical reactions that convert harmful hydrocarbon emissions into less harmful carbon dioxide and water. Since the 1970’s the United States has become more stringent on emission-control measures. Catalytic converters helped in reaching this goal, by the early 1980’s all new cars were required to be equipped with catalytic converters.
In Europe the use of catalysts started in the mid 1980's encouraged by the german automobile industry and European legislation.

Catalytic converters work by forcing the engine emissions past a honeycomb bed or past small beads. The beads or honeycomb bed are coated in special metals such as palladium or platinum. These metals are called catalists, meaning that they cause a reaction to occur quicker. This coating reacts with the heated exhaust gasses, and converts the initial exhaust into more environmentally friendly carbon dioxide and water (vapour). An efficient catalytic converter serves two purposes: It oxidizes CO and
unburned hydrocarbons to C02 and H20, and it reduces NO and N02 to N2 and 02.

Catalytic converters can only be used with unleaded gasoline. The reason for this is that the lead in leaded gas coats the catalytic metals making them no longer effective.

The 3-way-catalytic converter with Lambda-control is the most efficient technology to reduce emissions today. The raw emissions of the engine are reduced at least by 90%. The catalytic converter accelerates the conversion of nitrogen oxide (NOx), carbon monoxide (CO) und hydro carbon (HC) into  carbon dioxide (CO2), nitrogen and vapour (H2O). The fuel air ratio must be constant at 14,7 liter air and 1 liter fuel. This working condition is called lambda=1 where lambda is the fuel/air ratio.

Setup of the catalytic converter:
Catalysts are either made of ceramic or metallic bodies which carry a thin layer of  aluminum oxide - the so called wash-coat. The "active" zones contain about  1 to 3 gramm of platinium, rhodium or palladium. All this is fitted in a shock resistend tube which is mounted in the exhaust pipe system.
Is is convenient that the catalyst is mounted near the engine to gain it's working temperature beginning at  250 °C and leading up to 1100 °C. At higher temperatures misuse conditions are reached which destroy the catalyst.

Control system:
The catalytic converter is controled by the engine management system. An exhaust oxygen sensor is able to measure the percentage of oxygen in the exhaust stream and signals the engine’s on-board computer so that it can continually adjust the air/fuel mixture to the proper ratio. Volkswagen Beetles of the late 1970's  were delivered  in the U.S. with the BOSCH L-Jetronic injection system that controls the amount of fuel injected into the intake manifold. Also the Mexican Beetles produced from mid 1990 use a fuel injection system with one injection valve for each cylinder.
However most after market systems work much simpler. They use the existing Solex carburetor and control the amount of air with the help of a supplemantary magnetic valve - a bypass valve next to the carburetor.

Mounting at VW Flat4 Engines
 
Design "M"
System used in actual Beetles produced in Puebla, Mexico:

Dsign "A"
One transversal catalytic converter and Solex carburetor: Design "B"
Two transversal catalytic converters and Solex carburetor: Design "C"
One catalytic converter next to each cylinder head:
 
Catalytic Converter Kits - Market Overview (Germany)
This table includes the most important dealers of catalytic converter kits in Germany - perhaps there are more - so please inform flat4. There is no warranty for correct an actual informations. Please contact the dealers for further information like prices etc. Add +49 instead of the first "0" to the stated telephone number if you call from outside Germany. All the systems are efficient enough to be able to get the official german "G-Kat-Plakette" which enables these vehicles to run under severe smog conditions.
 
company (Germany) flat4 engine vehicle
key code acc. to
91/441/EWG
manufacturer
desing type
phone +49...
eMail
Beetlechoose a) 1.2 D, 1.6 AD, AS 
b) 34 kW (46 PS) mex. engine complete
Beetle, Karmann Ghia 
a) paper air filter 
 
77
HJS
A (V2A steel)
0911/7499519 
eMail
Hoffmann-Speedster 
Viersen
1.2, 1.6 Beetle, Karmann Ghia, 181 
 
?
?
B, V2A steel, metallic converter
02162/30022 
eMail
HJS  Fzg.-Techik GmbH 
Postfach 
D-58706 Menden
1.2 D  
1.6 AD, AS
Beetle, Karmann Ghia 
 
77
HJS-Kat 2000
A
02373/9870
Käfer Werkstatt  
Buchheim
Beetle, Karmann Ghia,  
181, Bus until '79
14
see P. Wurm GmbH
07665/3517
Paul Wurm GmbH  
Am Wildbädle 4 
D-70329 Stuttgart
1.2 D, 1.6  AD, AS, AR Beetle, Cabrio, 181  
Karmann Ghia, Bus 
 
14
System Wurm
A
metallic converter
0711/420071 
eMail
Heussner & Stauber  
Landwehrhagen
a) 35 kW complete engine (Mex.)  
b) 1.2 D, 1.6 AS, AD
Beetle
77
b) HJS, 
A
05543/9411-0
BB Automobiltechnik  
Siegen
a) 1.2 D 
b) 1.5 H, L, K 
c) 1.6 AD, AE, AF, AG, AH, AJ, AK, AL, AS, B
Beetle, Karmann Ghia, 
181, Bus 
 
77
HJS
A
0271/85033
Franz Bucher 
Mannheim
a) 1.2, 1.3, 1.6 HJS-Kat 
b) 1.2, 1.6 GAT-Kat 
c) 1.2, 1.6 Wurm-Kat 
d) 1.6 diverse
a) to c) Beetle, Karmann Ghia 
d) 1303 Cabrio, 181
a) 77
c) 14
see at flat4 engine
0621/33005-52 
eMail
Auto-Lenz 
D-69124 Heidelberg
1.2 D, 1.6 AD, AS Beetle
14
System Wurm
A
 
06221/785557 
eMail
GAT Abgastechnik GmbH 
Haldenstr. 14 
D-45966 Gladbeck
a) 1.2  
b) 1.3 
c) 1.6 AS
Beetle, Karmann Ghia  
since 1970
 
02043/9400-0
Kemmer & Hein  
Speyer (GAT-Kat.)
flat4 engines with 34, 44, 50 bhp Beetle, Karmann Ghia, 
181
 
06232/640365
Beetles Revival GmbH  
Wöbbelin
a) 35 kW complete engine (Mex.)  
b) after market systems
a) ACD 23-37 kW  
b) Type 11/13/14/15/18/23/34
 
038753/544
Willibald Tuning 
Bischofsheimer Weg 10 
D-97922 Lauda-Königsh.
a) 1.2 D, 1.3, 1.6  
b) Typ 4 1.9-2.9 liter engines
Beetle
 
09343/3300
D. Schmidt-Lorenz 
Havighorster Weg 14 
D-21031 Hamburg
1.2 D since 08/67 Beetle
77
 HJS
A
040/7385000
A&M Bug Stop  
Heilbronn
35 kW complete engine 
(Mexico)
ACD
 
07066/6561
Kerscher Motoren GmbH  
Rimbach-Dietring
tuned flat4 engines  
a) 68 kW  
b) 110 kW
RPEG 70/220/EWG  
89-491
 
08727/7392
Gerd Tafel  
Herdecke 
a) 1.6  
b) 1.1, 1.2, 1.6 
c) complete engine (Mex.) 35 kW
Beetle, Karmann Ghia Typ 14, 181, Bus, Type 3 
 
77
a) Design A
b) Design B
02330/74779
Sportwagen Eckert  
Neuburg
a) 1.2 D 
b) 1.5 H, L, K 
c) 1.6 AD, AE, AF, AG, AH, AJ, AK, AL, AS, B
Beetle, Karmann Ghia,  
181, Bus
77
HJS
A
08431/40740
VETERANENDIENST 
Peter Fried 
Obergasse 6 
87125 Dannstadt
1.2 D, 1.6 AD, AS Type 11 (70-87), 
Type 13 (72-76), 
Type 15 (70-81), 
Type 14, 34 (67-74)
77
HJS
A
06231/915295
Dannert GmbH 
Essener Str. 56 
42327 Wuppertal
a) Kit I: 1.6 
b) Kit II: other flat4 engines 
c) 35 kW (48 bhp) compl. engine (Mex.)
Beetle, KG Typ 14 
 
77
a) HJS, A ?
b) Design B ?
0202/27419-0
Käferland 
Hagenstr. 2  
60314 Frankfurt/M
1.6 AD, AS Beetle, KG Typ 14, 181
77
HJS
A
069/94413053
Alfred Knuf PTP 
Recklinghausen
1.2 D, 1.6 diverse Beetle
 
 
02361/26754 
eMail
 
 
European Emission Limits
 
legislation
carbon oxide
CO [g/km]
HC+NOX  [g/km]
german key code
german tax per 100 cm³ displacement
Euro 1 similar
3,14
1,13
77
13,20 DM
Euro 1
2,72
0,97
14
13,20 DM
Euro 2
2,20
0,50
25
12,00 DM
 
 
Developments in Unleaded Fuels
Focussed fuel components to reduce: The table shows what has been done so far.
 
introduction task
1972
Reduction of lead from 0,63 to 0,15 g/Liter
1985
Introduction of  unleaded fuel in Europe "Normal bleifrei" ROZ 91/MOZ 82,5 
Bezole maximum 5 Vol.%
1986
Introduction of unleaded premium fuel in Europe ROZ 95/MOZ 85 (Euro-Super)
1988
leaded fuel "Normalbenzin" is taken off the market in Germany
1989
Introduction of high octane unleaded fuel in Germany "Super Plus" ROZ 98/MOZ 88 
Benzole reduced to max.  2 Vol.%
1991
Scavanger additives taken off the market in Europe
1995
Commitment to reduce benzole to max. 1 Vol.% 
Additives replacing lead on the European market
1996
Leaded fuel no longer sold at gas stations
1997
Benzole reduzed in Germany to 1.8 Vol.%
2000
Reduction of benzole planned to 1 Vol.%
The future tasks will be to further reduce benzole and hydrocarbons with the help of

Literature:
 /1/ Advertisments in magazines "Oldtimer-Markt" und "VW Szene"
 /2/ Tips und Technik - Alles für die Kats, Oldtimer-Markt 12/96
 /3/ Bosch Kraftfahrtechnisches Taschenbuch
 /4/ Saubere Sache, VW Szene 04/96
 /5/ B. Woyta: Kat-Nachrüstung, Motor Klassik 12/96
 /6/ Saubermänner, Motor Klassik 03/96
 /7/ J. Matzan: Vorsprung durch Technik, Motor Klassik 01/92
 /8/ T. Melfi: Käfer-Stündchen, Auto Motor u. Sport 15/1991 Seite 138 ff
 /9/ Firmeninformationen der Anbieter
/10/ Deutsche Shell AG: Fakten u. Argumente, Aktuelle Themen aus der Mineralölwirtschaft, Nov. '97

 
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