Influence of Vehicle Technical Condition and Driving Technique on Fuel Consumption

Fuel Consumption Blog

Due to a combination of economic, resource, political, and environmental reasons, the urgency of the fuel diversification problem is growing every year. To date, the absolute leadership among engines of various types belongs to traditional gasoline engines, but there is a gradual increase in the share of electric engines, gas and hydrogen fuel engines.

Recently in many countries of the world the requirements for fuel quality in terms of their environmental safety have become stricter. This makes it necessary to look for alternative fuels and minimize the use of beznin. So how can we reduce gasoline consumption in our cars right now?

Influence of vehicle technical condition on fuel consumption

The technical condition of the vehicle and especially the engine, transmission and running gear has a noticeable impact on fuel consumption. About 30% of the rolling stock has increased fuel consumption due to various technical malfunctions or insufficient qualification of technical personnel and drivers.

Increase in the operating time of the vehicle is inevitably associated with a natural change in the basic adjustment parameters of the engine and technical condition of its units and systems, affecting the stability and quality of fuel posing, combustible mixture ignition and fuel consumption.

Fuel consumption related failures in the main units and systems of the vehicle are distributed as follows: power system – 30%, engine – 28%, ignition system – 26% and transmission – 16%.

Almost every car or motorcycle owner’s manual or repair book lists the scheduled maintenance of the vehicle depending on the mileage. This data is also called a maintenance schedule (check the Harley Davidson maintenance schedule).

Each of these schedules describes the necessary maintenance operations depending on the mileage. Each subsequent service may have its own designation. And, depending on the manufacturer, each maintenance service is performed at certain intervals.

The engine is one of the most unreliable units of a car. Failures and malfunctions of its main elements and systems reduce the efficiency of vehicle output parameters. Depending on the nature of malfunctions and functional features of these systems, fuel consumption can increase by up to 30%.

Characteristic malfunctions and misadjustments, as well as typical reasons for their occurrence in the work of automotive engines are associated with difficulties in starting a cold and warmed-up engine, unstable engine operation at idle, insufficient engine power and increased fuel consumption.

One of the main causes of fuel overconsumption – insufficient technical condition and maintenance of vehicles, especially power and ignition systems. ,

Only a technically sound and properly adjusted vehicle can provide a high degree of fuel efficiency. Leaky exhaust valves and poor valve clearance are a direct consequence of increased VOC concentrations and fuel consumption.

Qualified drivers pay special attention to the technical condition of the vehicle and are very demanding of timely and quality maintenance and servicing. All this provides for reduction of fuel consumption by 5-10%.

The technical condition of the chassis and transmission is determined by a complex index – the car’s mileage. Various operational malfunctions of these systems are accompanied by additional engine load when performing the same transport work.

Feeding system of carbureted engines. Violation of the correct operation of the power system is associated primarily with changes in the technical condition of the carburetor, fuel and air purification units, gasoline pump, fuel lines and gasoline tank.

Typical malfunctions of fuel and air cleaning units are increased hydraulic resistance and decreased flow capacity, and deterioration of filtering quality.

Leaky intake piping and carburetor mountings cause additional uncontrolled air suction and disturbed engine operation at low loads, and particularly at idle.

Idle Speed System. In motor transport, limitation of toxicity of exhaust gases is carried out mainly by reducing the CO content in them, which reaches its maximum value at engine operation at idling and at acceleration modes of the vehicle. Idling modes are the limiting case of engine throttling. The engine fill factor in this case is 0.18-0.2, and the coefficient of residual gases is 0.25-0.35. The marked features are associated with the need to enrich the combustible mixture.

In the process of operation, 60-75% of carburetors give an over-enriched composition of the combustible mixture at the minimum engine speed, which is accompanied by overconsumption of fuel at 1.7-2.3%. The number of carburetors operating with over-enriched combustible mixture makes only 8-10 % and is accompanied by overconsumption of fuel by 1-1,5 %. In case of wrong adjustment of the idling system, the emission of products of incomplete combustion of CO and CH increases by 35-40% and 30-35% respectively.

Influence of driving technique on fuel economy

The effect of driving technique on fuel consumption can vary by as much as 20-25%. Frequent braking increases fuel consumption, because every time the driver has to force the engine for another acceleration, so the steady motion mode is preferable. It is also necessary to keep the engine in a normal thermal condition, since both overheating and overcooling of the engine lead to overfueling.

High driving speeds certainly cause increased fuel consumption, as they have to overcome air resistance, and it increases in proportion to driving speed. For example, at a truck speed of 70 km / h to overcome air resistance costs traction on the drive wheels is 10 times greater, than at a speed of 30 km / h. But in order to increase the traction force, it is necessary to obtain additional thermal energy, for which additional fuel will be spent.

An empty roof rack increases fuel consumption by 3-4 %. Consumption increases even more when driving with open windows.

When the car is fully loaded, the range of economical speeds increases, because the fuel efficiency of the engine designed for this load improves. A front-wheel drive vehicle is significantly more fuel efficient than a rear-wheel drive vehicle. A front wheel drive vehicle can save up to 6-8% fuel at a constant speed.

Rational use of different gears during the operation of the car effectively promotes fuel economy. Driving a vehicle at a constant speed is possible in a high gear as well as in a low gear preceding it. Driving in a lower gear at a lower speed does not use engine power efficiently enough and uses 15-45% more fuel than in a higher gear. Fuel consumption increases in proportion to the lower gear ratio, so the choice of a lower gear must be justified by the driving conditions. Using a lower gear is advisable only when maneuvering a vehicle or a road train, when driving in heavy road conditions, off-road, etc. If there is no need to use a lower gear, you should immediately change to a higher gear.

Repeated alternation of decelerating and accelerating creates an unsteady speed pattern, and impairs the fuel efficiency of the vehicle.

A large amount of fuel is consumed when overtaking, i.e. 20-25% more than driving at a constant speed. It is not allowed to drive at a low speed for a long time, as it also increases fuel consumption.

Deceleration of the car through the braking system is the most uneconomical, and it is better not to use it without an absolute necessity. For example, it is advisable to approach a traffic light at the moment of turning on a green light. In this case the slowing down, stopping and acceleration of the car is excluded, which provides significant fuel savings. If such approach to the traffic light is not possible, then before the intersection you should move forward without the use of braking systems. However, you need to be careful and cautious not to create an emergency situation.

Stopping the car involves additional fuel consumption for slowing down and idling the engine while it is parked, so in order to save fuel you should try to avoid unintended stops along the way.

Fuel consumption at short stops at traffic lights and junctions is reduced if the engine operates at a low speed of the crankshaft. At work of the engine during 1 hour in idling mode the fuel consumption is 1-2.5 liters.

Thus, fuel economy largely depends on what driving style the driver adheres to.