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

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SEPTEMBER 2019 ŠKODA MOBIL 13