How does the gearbox influence fuel consumption?
Bearings
Engagement
of gears
Bevel
Gear ratios
and number of gears
Weight of the gearbox
Ball
Gearbox oil
Mechatronics – automatic
transmission control
ENVIRONMENTAL
ALTERNATIVES
MQ 200 – 6-speed
mechanical transmission
ŠKODA AUTO PRESENTED ITS G-TEC
CARS AT THE FRANKFURT MOTOR
SHOW
A
fter the OCTAVIA COMBI G-TEC, the
group of ŠKODA cars powered by natural gas (CNG) has been expanded to include a study of the compact SCALA G-TEC
and the urban KAMIQ G-TEC SUV. “As part
of our efforts to reduce CO2 emissions, natural gas plays an important role for ŠKODA in
its powertrain supply,” says Christian Strube, ŠKODA Board Member for Technical Development. “Owing to lower emissions and
low fuel prices in many countries, our G-TEC
models will become increasingly popular,” he
adds.
The car engine design has been specially
adapted for burning environmentally friendly
natural gas. Petrol, which is located in an additional 9-litre tank, is only used in certain engine start situations: tank pressure changes
and drops, and when outdoor temperatures
fall below −10°C. The petrol tank also functions as a reserve in case no CNG filling station is available. The switching between the
two modes is automatic without any driver
intervention.
CNG contains more energy than gasoline
or diesel. It is cheaper and burns quietly. CO2
emissions are approximately 20 percent lower
than with petrol. Moreover, the combustion of
CNG produces much less nitrogen oxide and
no carbon soot. The environmental balance
will be significantly improved if biogas produced from waste water or agricultural products
or synthetic gas is burned instead of CNG. In
addition, the environmental balance may be
improved if electricity from regenerative sources is used for gas production. RED
Scan the QR
code for an
overview of cars
with alternative
drives.
Sealing ring
Differential
HOW THE GEARBOX
AFFECTS CONSUMPTION
BOTH ITS DESIGN AND THE WAY IT IS USED WHILE DRIVING CAN AFFECT
THE ENVIRONMENT
T
he 37th ŠKODA Economy Run took place on influenced simply by choosing the bearing type. Slithe penultimate Sunday of September. The ding friction does not occur in the ball and roller beresults of the vehicles entered in this run re- arings, unlike in the bevelled bearings, and the loss
gularly prove the extent to which the carmaker is is halved. However, this solution places great decutting fuel consumption and CO 2 emissions in mands on the dimensioning of the bearings as they
its models. The entrants in the economy run utilise must carry both radial and axial forces.
many vehicle functions. However,
At present, every fuel consumptithey receive significant assistance
on percentage is counted, and it
The MQ 200 five- or
from the gearbox, whose design
is not even possible to ignore the
six-speed gearbox
and mode of use have a direct imenergy used to control the gearis made in Mladá
pact on fuel consumption.
box. In the case of the mechaniBoleslav in a total of
A normal car with a fuel consumpcal gearbox, the required energy
50 configurations,
is provided by the driver through
tion of 6 litres produces about 140
which are installed in the
grams of CO2 per kilometre. The
his left leg and right hand – that is
models of the various
number of gears and their mutuby pressing the clutch and engaVW Group brands.
al ratios influence the dynamic
ging the gears. In the case of an
drive capability of the car and its
automatic transmission, this must
economic operation. Their higher number, howe- be provided by the engine. Control of the automaver, not only increases the price but also weight of tic transmission requires pressured oil and, therefothe gearbox, which results in higher fuel consumpti- re, also a pump.
on and, hence, also CO2 emissions. A further factor
affecting the engine economy is the gearbox’s own Driver behaviour
loss of power. The gearbox is responsible for about The automatic transmission shifts gears with ma6 percent of total power loss (the gearbox is liable ximum precision. Its energy demand is successfufor a fuel loss of 3 to 4 litres every 1,000 kilometres). lly balanced by the control software, which knows
About 50 percent of this loss is primarily accrued precisely when it is best to shift the gear and how
through friction during engagement of the gears to use the engine power efficiently. In Eco driving
and slipping of the differential when running throu- mode, the gearbox shifts gears at low rpm so that
gh a bend. About 10 percent consists of oil loss, seal the fuel consumption is as low as possible. This
ring tightness etc., and little can be done about this mode also allows for “coasting”. If the software evaloss for technical and economic reasons.
luates that it is suitable after a reduction in acceleration to allow coasting in neutral, it activates this
Designer opportunity
mode. A predictive driver can better utilise the kiThe remaining approximately 40 percent accrues netic energy of the car and reduce fuel consumptifrom loss in the bearings. The shafts are most of- on. A driver with a manual transmission gear stick
ten mounted either in two bevelled taper bearings in hand also has great influence over fuel consumpor in one ball and one roller bearing. Both variants tion and CO2 emissions. It is enough for them to cohave their advantages and usage limits. And the rrectly shift gears and avoid driving in excessively
overall mechanical efficiency of the gearbox can be low or high gears. RED
Did you
know that...
… in 2018 alone, ŠKODA
AUTO manufactured
371,700 type MQ 200
gearboxes? At the
Mladá Boleslav plant,
they are installed in the
FABIA, SCALA, KAMIQ,
OCTAVIA and KAROQ
models in combination
with 1.0- to 1.6-litre petrol
engines. The current total
daily production volume of
the MQ 200 gearboxes is
more than 1,600 units.
DETAILS ON THE GIVEN TOPIC,
INCLUDING TECHNICAL ISSUES
OF INTEREST, ARE AVAILABLE AT
Employee Portal > News
SEPTEMBER 2019 ŠKODA MOBIL 13