Motorhantering under stopptid : tomgång eller avstängning. Utsläpp under krypkörning: avgasmätningar och litteraturgenomgång

• There is a scarcity of data on which decisions can be based regarding thelimitation of idling during standstill periods. There is also reason tobelieve that the significance of engine management during standstill may varybetween different propulsion systems and technical standards etc, which willincrease the need for a decision base. The need for data that describe exhaustemissions during crawling speed is particularly great in the case of tunnels.Ventilation plants in tunnels are designed on the basis of relationshipsbetween emissions and mean speed. Up till now, for speeds below 30 km/h, theserelationships have not been satisfactorily based on measured data. The primaryobjective has been to fill the gaps in knowledge by exhaust measurements. Themethodology has comprised a survey of the literature, measurements andanalyses. Different objectives result in different limiting times for idlingduring standstill periods. For the vehicle fleet as a whole, different limitshave been estimated for different objectives: for private economy, 12 seconds;for macro economy overall, 23 seconds; for energy policy, 12 seconds, and forair quality, 36 seconds. There are also time limits per compound, pertechnical standard and per vehicle type. The time for diesel is shorter thanfor petrol engine. According to measurements, emission of oxides of nitrogen(NOx) at crawling speed varies over the range -51 and 171% for differentengine types when speed drops from 25 to 10 km/h. There are considerabledifferences in the speed dependence of fuel consumption both between andwithin studies. The relationships which could be estimated for particulateemissions do not, in any one case, indicate an increase in emission as speeddrops from 25 km/h.

Nyckelord

Emission

Measurement

Idling

Snow

Driving

Speed

Time

Carbon dioxide

Hydrocarbon

Carbon monoxide

Nitrogen oxide

Particle

Air pollution

Catalytic converter

Petrol

Diesel engine

Calculation

Mathematical model

Road: Environment

Road: Environment

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)