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Cylinder Deactivation –
A technology with a future or a niche application?
Dave Kehr
First application: Cadillac Seville
1981
6.0L V8 OHV
864
1
Schaeffler Symposium 2014
Dave Kehr
Examples for cylinder deactivation in mass production
3.9L V6
5.8L V12
6.0L V8
4.0L V8
6.0L V8
5.0L V8
3.5L V6
6 3/4L V8
1.4L I4
Why the gap?
1980
1990
2000
2010
5.7L V8
5.5L V8
6.5L V12
5.3L V8
6.4L V8
2
Schaeffler Symposium 2014
Dave Kehr
8-cylinder mode
Lowest
specific fuel
consumption
Torque in Nm
Torque in Nm
Operating principal of cylinder deactivation
Constant
specific fuel
consumption
4-cylinder mode
Engine is
operating closer to
lowest fuel
consumption
Road load curve
Engine Speed in rpm
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Schaeffler Symposium 2014
Dave Kehr
Engine Speed in rpm
Fuel consumption improvement potential
10
Benefit for 4
cylinder mode
 be in %
1.4L 4 cyl.
 with 2 cyl.
Differenz-Kennfeld
1,4l operation
4Z
20
gegenüber 1,4l 4Z - ZAS
bar
18
16
effective
brake mean
p
pressure in bar
4
12
10
7
2
6
8
8
6
6
me
Theoretical
switching
threshold
14
8
0
4
-2
-4
2
-6
5
0
-2
Optimum
combustion
-4
4
-6
-8
-8
3
-10
-12
-10
-14
-12
2
-18
-20
-16
-14
-16
1
-18
-20
0
1000
1500
2000
n
engine speed in rpm
4
Schaeffler Symposium 2014
Dave Kehr
min-1
3000
Benefit for 2
cylinder mode
6
Traditional
BDC TDC BDC TDC BDC TDC BDC TDC BDC TDC
Higher combustion pressures
Drehzahlbereich
More pressure variation
Recent
development
BDC TDC BDC TDC BDC TDC BDC TDC BDC TDC
Lower combustion pressures
Less pressure variation
Direct injection can improve cylinder deactivation NVH
5
Schaeffler Symposium 2014
Dave Kehr
Source: MTZ "The New AMG 5.5L V8 Naturally Aspirated Engine with Cylinder Shut-off"
Two different cylinder deactivation strategies
Actual filling
Cylinder filling
(Throttle position)
Ignition angleefficiency
8 Cyl. Mode
6
Schaeffler Symposium 2014
Dave Kehr
Switch-over phase
4 Cyl. Mode
Time
Source: MTZ Source: MTZ The new Audi V8 TFSI Engine Part 2
Filling- target
Actuator shifting
Engine Torque
Switching strategy – managing torque change
Switchable finger follower
Working principle
Valve train with switchable
finger follower and hydraulic
support element
7
Schaeffler Symposium 2014
Dave Kehr
Switchable finger follower
Full lift mode
Exhaust
Intake
Deactivation mode
Exhaust
Intake
Oil supply
8
Schaeffler Symposium 2014
Dave Kehr
Switchable pivot element
Working principle
Oil supply
9
Schaeffler Symposium 2014
Dave Kehr
Controlled oil circuit layout
Oil circuit design
 Switching window
independent VCT
Parallel
Intake
cyl 1
Cylinder selectable
10
Advantages
cyl 2
cyl 3
cyl 4
 Switching window
up to 180° (cam)
Exhaust
 Simple oil galleries
Intake
 Switching window
up to 250° (cam) VCT Influence
cyl 1
cyl 2
cyl 4
 Cylinder selective
Exhaust
Schaeffler Symposium 2014
cyl 3
 Compact oil
galleries
Dave Kehr
Variable valve lift by cam shifting system (2-step)
System
Advantages
 Cylinder- and camshaft selective
variability
 Provides OBD signal
 Can be upgraded to 3-step
(modular principle)
11
Schaeffler Symposium 2014
Dave Kehr
Chapter
Title
Variabilität durch SchiebenockenSystem (2-Stufigkeit)
- Zylinder- und
nockenwellenselektive Variabilität
- OBD-Signal "aktiv/integriert"
 ausbaufähig zur 3-Stufigkeit
(Baukastenprinzip)
12
Schaeffler Symposium Dave
2014 Kehr
Electro-hydraulic valve train systems
Uniair-System
Advantages
 Fully variable Lift
 Zero lift capable
 Provides OBD
signal
13
Schaeffler Symposium 2014
Dave Kehr
Fuel Consumption Reduction in %
Fuel consumption improvement potential using CDA
15
8
5
8
6
4
4
3
Number of Cylinders per Engine
14
Schaeffler Symposium 2014
Dave Kehr
Final thoughts
We offer the right components…
…for fuel efficient technology
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Schaeffler Symposium 2014
Dave Kehr
‟
By failing to prepare,
you are preparing to fail
”
Benjamin Franklin
1706 – 1790