PROJECT 1

PROJECT 1

(Deactivation Cylinder Engine)

Name: Danial bin Abd Malek
No Matric: A17KM0069
No IC: 980402145197
Course Code: SKMM 2423 (Applied Thermodynamics)
Lecturer: Dr Zulkarnain bin Abdul Latiff
Section: 4

The objectives of this project are to gain knowledge about the technology that was assigned
for example deactivation cylinder engine. Besides, the other objective of this project is to learn
about the fundamental of the technology that related to our courses like Thermodynamics and
Applied Thermodynamics. Lastly, the objective of this project is to learn how this technology
works and make our life easier in terms of economy and others.

There are currently two main types of cylinder deactivation engine mechanizations used
today, depending on the type of the engine's valve train. The first is for pushrod designs which
uses solenoids to alter oil pressure delivered to lock pins in the lifters. With lock pin out of
place, the lifters are collapsed and unable to elevate their companion pushrods under the valve
rocker arms, resulting in valves that remain closed when the cam pushes on the part in lost
motion.

The second type is for overhead cam engines, and uses a pair of locked-together rocker arms
that are employed for each valve. One rocker follows the cam profile, while the other actuates
the valve. When a cylinder is deactivated, solenoid-controlled oil pressure releases a locking
pin between the two rocker arms. While one arm still follows the camshaft, the unlocked arm
remains motionless and doesn't move the valve. With computer control, fast cylinder
deactivation and reactivation occur almost instantly.

The methodology of deactivation cylinder engine is valves at the top of the cylinder open
and shut in a specific pattern to precisely allow fuel and exhaust gasses in and out of the
cylinder. When an engine fitted with cylinder deactivation detects the car is cruising, a solenoid
valve opens and a system forces the valves shut, preventing fuel and air from reaching some of
the cylinders. This means combustion is only taking place in half of the engine and thus much
less fuel is burned when cruising.

To make sure the system engages and disengages imperceptibly, and does not cause damage
to the engine, it is very precisely controlled by the car’s computer. The system detects if you
are at a roundabout or anywhere where you might need a burst of power and deactivates, only
coming in once it is sure you do not need the extra power. In fact, the only way most owners
will know if it is on or not is by a readout in the instrument cluster.

This is the method of deactivating cylinder engine according to requirement of power to
achieve better fuel efficiency and also emission control. It works because only a small fraction
of an engine’s peak horsepower is needed to maintain cruising speed. Each cylinder is disabled
only at the intake and exhaust stroke. It takes 40 to 50 milliseconds. Each cylinder also disabled
by interrupting the operation of intake and exhausts valves with spark and fuel delivery.

The impacts of the deactivation cylinder engine are cylinder deactivation is used to reduce
the fuel consumption and emissions of an internal combustion engine during light-load
operation. In typical light-load driving the driver uses only around 30 percent of an engine’s
maximum power. In these conditions, the throttle valve is nearly closed, and the engine needs
to work to draw air. This causes an inefficiency known as pumping loss. Some large capacity
engines need to be throttled so much at light load that the cylinder pressure at top dead centre is
approximately half that of a small 4-cylinder engine. Low cylinder pressure results in
lower fuel efficiency. The use of cylinder deactivation at light load means there are fewer
cylinders drawing air from the intake manifold, which works to increase its fluid (air) pressure.
Operation without variable displacement is wasteful because fuel is continuously pumped into
each cylinder and combusted even though maximum performance is not required. By shutting
down half of an engine's cylinders, the amount of fuel being consumed is much less. Between
reducing the pumping losses, which increases pressure in each operating cylinder, and
decreasing the amount of fuel being pumped into the cylinders, fuel consumption can be
reduced by 8 to 25 percent in highway conditions.

Cylinder deactivation is achieved by keeping the intake and exhaust valves closed for a
particular cylinder. By keeping the intake and exhaust valves closed, it creates an "air spring"
in the combustion chamber, the trapped exhaust gases (kept from the previous charge burn) are
compressed during the piston’s upstroke and push down on the piston during its down stroke.
The compression and decompression of the trapped exhaust gases have an equalising effect
overall, there is virtually no extra load on the engine. In the latest breed of cylinder deactivation
systems, the engine management system is also used to cut fuel delivery to the disabled
cylinders. The transition between normal engine operation and cylinder deactivation is also
smoothed, using changes in ignition timing, cam timing and throttle position (thanks
to electronic throttle control). In most instances, cylinder deactivation is applied to relatively
large displacement engines that are particularly inefficient at light load. In the case of a V12,
up to 6 cylinders can be disabled.

The ‘brain’ of the engine is the electronic control unit (ECU). In a vehicle equipped with
CDS, the ECU selectively deactivates cylinders by deactivating the intake and exhaust valves
and fuel injectors. Although this practice reduces the power available, the engine does not need
all of its cylinders to maintain the vehicle speed under constant throttle applications, such as
highway or downhill driving. When more power is required (such as uphill driving or
acceleration) the ECU reactivates the valves and fuel injector of the deactivated cylinders,
which returns the engine to full power. Although no combustion occurs in the deactivated
cylinders, their pistons continue to move, and oil continues to circulate. The energy cost to
keep the pistons moving and oil circulating is outweighed by the fuel savings.

There are some advantages of deactivation cylinder engines. Firstly, it will increase the
efficiency of the fuel about 10 to 25 percent. Other than that, it will decrease the emissions
from the deactivation cylinder engine. Lastly, it will improve the breathing capability of the
engines, thereby reducing the power consumed in suction stroke.

Deactivation cylinder engines also has their own disadvantages. Firstly, the deactivation
cylinder can cause in engine balancing which leads to violent vibration and noises. The way of
attaching counter masses to the moving parts like crankshaft is very difficult to calculate and
attach the counter masses. Other than that, though the deactivation process reduces operation
costs, the additional parts like ECM and others will increase the cost of manufacturing. Besides,
the overall weight will increase and the complexity of system makes maintenance difficult.
Lastly, since these methods are still under experimental stage, the reliability of the engine is
not predicted yet.

In conclusion, I want to say thank you to my lecturer for giving this project so I can gain
much knowledge this kind of technology for example deactivation cylinder engine such as
advantages and disadvantages of the deactivation cylinder engines. During I am doing this
project, I can learn what is fundamental of this kind of technology that may be related to our
courses Thermodynamics and Applied Thermodynamics and how the deactivation cylinder
engine works. I am also can learn what the impacts of the deactivation cylinder engine towards
work, fuel consumption, efficiency, environment and social.

To reduce the pollution from the internal combustion engines and the demand of automobile
which burns less fuel. With the increase of price of petroleum products, the fuel is burnt
according to the power requirement. So, cylinder deactivation solves these kind of problem to
a great extend without compromising engine performance thus satisfies both manufacturer and
consumer.

The recommendations of the deactivation cylinder engine are during these high-speed low-
load conditions, the air-to-fuel ratio is elevated, given the reduced fuelling required at low loads
and the engine “over breathing” at low loads, and to prepare for a sudden increase in fuelling
resulting from a commanded increase in desired torque and power. There are several possible
strategies for improving the engine torque response to acceptable levels when air-to-fuel ratios
are reduced at high-speed, low-load operating conditions, including early exhaust valve
opening, internal exhaust gas recirculation via combustion gas trapping or re-induction,
turbocharger electrification supercharging, powertrain hybridization and availability of look-
ahead information, through vehicle data connectivity with other vehicles or the Cloud, to allow
anticipation of an upcoming transient.

These methods are not the subject matter discussed in detail in this paper. Instead, this paper
outlines strategies for achieving and the benefits of low air-to-fuel ratio operation at high-
speed, low-load conditions. Air-to-fuel ratio reduction strategies considered in this paper
include “opening up” the variable geometry turbine turbocharger (VGT), reducing the
displaced volume through cylinder deactivation, reducing volumetric efficiency via late intake
valve closure (IVC) and some combination of these strategies.

REFERENCES

 "Cylinder Deactivation Reborn - Part 1, Autospeed, Issue 342, Michael Knowling".
Archived from the original on 2005-11-09.

 "Cylinder Deactivation", About.com, Christine & Scott Gable
 "Active Cylinder Technology (ACT)". Archived from the original on 2017-06-21.

Retrieved 2018-01-21.

Figure 1: Cylinder Deactivation Engine
Table 1 shows what a cylinder deactivation system can save you over time