Cold start

The cold starts, we can classify each engine start, which is heated to operating temperature. In this category falls the morning only way to work, but also maneuvering between purchases, etc. When a cold start is due to insufficient lubrication of the wear and tear of mechanical parts. Emissions are also very high, because the catalyst needs to reach its correct operating temperature operation. And what about fuel consumption? Consequently, there are better not ask.

Cold engine has not only resulted in higher fuel consumption, high exhaust emissions , but also increased wear of mechanical parts. Many drivers do not know that a few seconds after start there is a dry and polosuchému friction. Then there are some enormous mechanical wear groups. The lubricating oil system is not enough pressure and oil film on the contact surface is insufficient or lacking. Therefore, every correct driver to wait at least a few seconds before he gets going. But who among us does?

Even after the first minutes of running the engine is not won! You ask when the engine is warm enough? As a guide to some drivers may serve thermometer (if it is equipped with a dashboard), but even this device is not foolproof. Because the thermometer shows the temperature of coolant, no oil! Motor oil has good lubricating properties around 80 ° C. An oil temperature indicator, however, exceptions and sports cars, you will not find in a car. It can be tentatively advise that ideally the engine is warmed up to 20 kilometers away. But again it depends on ambient temperature and vehicle speed. Until then, the driver should be avoided if high engine speed. As a fuse have some heavy duty engines (eg BMW M), helping a number of red LEDs, which extends a red box appropriately restricted speed. When heated to operating temperature diodes automatically turning off.

A cold engine is consuming more ...
Cold ... engine needs to run smoothly and sufficient power richer mixture. Consumption is growing due to higher idling speed. Therefore, the big advantage of independent systems that preheated the engine coolant. Minimize the negative aspects of cold starts and they can be used to předvytápění interior. Additional auxiliary heating consumption is approx. 0.5 liters per 1 hour of operation. There are also electric versions widely used primarily in Scandinavia.

Exhaust emissions are at almost double the cold engine. This is because the engine burns a mixture of rich, cold oil has a higher viscosity (resistance) and the catalyst has not reached operating temperature. For gasoline engines, there is usually heated for 40 seconds after launch. Even worse is the situation for diesel engines. Particulate filter is needed for its correct operation temperature of approx. 600 ° C, otherwise it clogs soot. Manufacturers warn against purely urban operation of diesel engines!

VALUES - VOLKSWAGEN GOLF 2.0 TDi
g / km	cold engine	heated engine
CO	0.588	0.215
CO ₂	296	262
HC	0.162	0.080
NO _X	0.841	0.555

What You Did not Know:

Cold start on LPG and CNG
Combustion of LPG or compressed natural gas ( CNG ) is problematic on a cold motor. Therefore, this modified engines usually start on petrol. Only the engine is warm is to manually or automatically switch to gas.

Frequent cold starts shorten the service interval
Cars have set the length of the service interval. Frequent cold starts, however, the interval required service visits reduced. Thus, if the vehicle is not equipped with a system for variable length intervals (eg ASSYST ) can cause excessive wear and damage to some parts, such as clogging of the particulate filter .