Throttle: single part or whole system?
Any mechanical vehicle will not be able to move without the appropriate fuel. As engine crankshaft rpm increases, consumption of gasoline-air mixture, correct preparation of which is assigned to throttle valve, increases.
Features of throttle valve operation in the power unit inlet system
The intake system of the engine is built in such a way that it combines two systems: fuel supply and mixture enrichment. The fuel supply system assumes the role of the gasoline transporter from the tank to the power unit, and the throttle valve is already responsible for its enrichment.
Depending on the crankshaft speed, the system vacuum changes. When the throttle valve is in the open position, the process of mixing air with fuel takes place, that is, air enters the intake manifold at this time, and the control system, through the nozzles, injections the necessary amount of gasoline.
Let ‘s turn to history
If, as they say, “dig deeper” in the history of the automobile industry, several curious features will be revealed. The whole thing is that gasoline has not been used as fuel for automobile motors for a long time. The first power units were operated on light gas, so there was no need for fuel enrichment, as the gas already included oxygen, which provided complete combustion of the fuel. But the operation of the engine on light gas could not be called economically viable, because of its expensive production, and lack of capacity to do so.
This was a prerequisite for the development of alternative sources of fuel for motor vehicles. Kerosene was perfect for that. Gasoline and diesel were invented a little later. After the discovery of these energy sources in 1872, a device was invented to enrich the working fuel mixture now known as a “carburetor,” in the system of which one of the most basic parts was a throttle valve, thanks to which the whole process of mixing formation is carried out. A few later, V. Maibach and G. Daimler officially patented it.
What is a throttle?
Structurally, this carburetor element is a valve that, in the open state, triggers air inside the powertrain, equalizing the pressure with the atmospheric pressure. But, it is worth closing the throttle valve as a vacuum is immediately formed in the system. The throttle valve device is represented by the following structure: in the center of the round metal housing there is an axle with a locking round segment, the diameter of which is equal to the diameter of the housing. The drive controls the circular shutter, changing the cross-section of the housing, thereby changing the composition of the working mixture. That is, throttling occurs.
Note that the design of diesel power units does not provide for the use of a throttle valve. The process of working mixture formation in them takes place at the stage of fuel supply.
Initially, in the design of older carburetor models, the shutter was controlled by a cable connected to a gas pedal. Even in injector systems, a mechanical type of drive was used for quite a long time until it was finally displaced by the electronic control system. That is, the accelerator became the main control device in its design, which by means of an electric signal corrected the position of the throttle valve.
But, the mechanical drive of the shutter never managed to finally run in the summer. Today it is used on budget class models. The whole domestic automobile industry until 2003 is equipped with this type of throttle control. By the way, it has been used for about two centuries, as it today is characterized by simplicity of its design and convenience in carrying out maintenance.
The electronic throttle control system used in modern vehicles is no longer fully subject to the driver ‘s instructions, as the mixing is the responsibility of its actuating modules: throttle valve control sensors, accelerator pedals, idling, etc.
Such a mixing system makes it possible to calculate fuel consumption as accurately as possible depending on operating modes of the power unit and to stabilize its idle speed.
Is it important to keep the throttle flap clean?
Sea air, which constantly passes through the throttle flap, does not differ in its purity due to the fact that it constantly contains particles of dirt and dust. Even the highest quality and most modern air filter is unable to completely clean the air. In addition, waste oil with dirt particles is constantly accumulated on the plane of the shutter, which penetrates there through the ventilation duct of the crankcase. It is not difficult to imagine how this will affect the operation of the entire mixing system, and in particular the shutter, which is constantly covered by the raid that prevents its normal functioning.
By the way, the accumulation of dirt and plaque on the throttle flap today is one of the common reasons to travel to the car service.
The following signs indicate the need to clean the flap:
- “Floating” idle RPM;
- Unstable motor operation;
- Difficult start-up.
The cleaning procedure is quite simple and will not take long. For this purpose it is enough to remove the branch pipe of the air purification filter, and to treat the shutter with special cleaning agent or gasoline, after which, after waiting for some time, remove dissolved plaque with rags or napkin. In case of more serious contamination, it is recommended to remove the shutter and clean it with the same means.