How to adjust the throttle when driving at high altitude

Previously, some netizens posted that they were driving in Tibet and going to go on road trip. After arriving at the Qinghai-Tibet Plateau, they found that the power of the car was not as good as before, but? The same tank of oil has a longer journey. What the hell is going on here? In fact, cars are really lacking in power in plateau areas, and even some car owners find that the average fuel consumption has also decreased. This is mainly caused by the decrease of actual oxygen content in the air entering the engine due to the thin plateau air.

Why does the engine output power? Figuratively speaking, both air and gasoline enter the cylinder to form a mixture. The piston violently compresses the mixture into small balls, and then the spark plug ignites the mixture. The intense combustion of the mixture produces a lot of energy, which pushes the piston out like an explosion, thus generating power.

It can be seen that the more mixed gas the piston compresses, the greater the energy generated during combustion.

The lack of plateau power is due to the lack of mixed gas.

How much oil the engine injects depends on the intake air. After all, gasoline must have oxygen to burn. Doesn't mean you can improve your power by injecting more fuel. If there is insufficient oxygen, gasoline can't burn completely or it just emits black smoke without power.

The air on the plateau is low in oxygen content, so there is actually less oxygen available after inhaling the same volume of air. At this time, the gasoline entering the cylinder cannot be completely burned, oxygen is consumed, and some gasoline is not burned. The oxygen sensor will find this situation when exhausting, so the ECU will reduce the fuel injection to adjust the air-fuel ratio, which is beneficial to the complete combustion of gasoline. Since then, the motivation has declined.

What is the reason for the decrease of fuel consumption in plateau?

The thin air here reduces the fuel injection, which is equivalent to forcing you to drive gently. But there is another reason that will also lead to the reduction of fuel consumption, that is, the pumping loss of the engine on the plateau is also reduced.

What is pumping loss? For example, when we drink through a straw, the thicker the straw, the more energy-saving it is. If the straw is thin, it will make our cheeks sour. The same is true for engine suction.

In the intake stroke, air from the air cleaner passes through the air inlet, throttle valve, intake manifold and intake valve to the cylinder. There will be some resistance in the middle, called the pumping loss of the engine. Pump loss also consumes engine power, and reducing pump loss can reduce fuel consumption.

In the intake system, the throttle valve will produce great pumping loss because the throttle valve controls the intake. In general, the throttle opening is very small, which has a great obstacle to air intake. For example, when idling, this thing in the picture above has only one crack. Do you think the engine is tired of inhaling?

The heavier the accelerator pedal, the greater the throttle opening and the smaller the obstacle to air intake. For example, as shown in the above figure, after the accelerator pedal is pressed to the bottom, the throttle valve is fully opened, and the air intake of the engine is smoother. What will we do when the power on the plateau is insufficient? Must have stepped on the gas. Therefore, the throttle opening increases, the intake resistance decreases, the pumping loss of the engine decreases, and the fuel consumption can be reduced.

Therefore, it is not a rumor that the power and fuel consumption of cars on the plateau have also decreased. That's true in theory.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.