The Acoustic Control Induction Technology, sometimes known as ACIS, is a Toyota invention that uses a variable-length intake manifold system.
Simply described, the ACIS system adjusts the length of the intake tract using a single intake air management valve, which is positioned in the intake, to maximize power and torque, improve fuel economy, and lessen intake “roar.”
Based on input signals from the throttle angle and engine RPM, the engine control unit (ECU) regulates the position of one or more air control valves. When the vacuum switching valve (VSV), which regulates the vacuum supply to the actuator, is powered by the ECU, it opens and allows vacuum to flow to the actuator. The air control valve is closed by passing vacuum to the actuator after the VSV is powered up. The intake manifold run is essentially lengthened as a result. Vacuum to the actuator is blocked when the VSV is de-energized, and any trapped vacuum is drained off of the actuator diaphragm. An On/Off system is Toyota ACIS. The valve is either fully opened or fully closed (in modern models with several valves to provide more than two lengths).
The 3.0L 3VZ-FE engine is an example of early single-valve ACIS programming. When the throttle position is 60% or higher and the engine speed is 3,900 RPM or more, the ECU activates the VSV to close the valve. [Reference needed]
In This Article...
How can my Toyota VSV be tested?
Disconnect the canister side line from the valve and watch the VPS signal while providing low pressure or vacuum from the EVAP tester to the line with the valve commanded open to test the bypass VSV. The change should be read by the VPS.
What is Toyota’s VSV?
Vapor switching valves (VSVs) for evap systems are a crucial tool for system diagnosis. Dan explains in this chapter of the series. Page 1. In our ongoing series on Toyota’s early or nonintrusive evaporative emissions technologies, this is the fourth part.
A vacuum valve is what?
A vacuum valve is a component installed in a vacuum system’s supply or exhaust line. It is typically used to manage gas volumes entering and leaving vacuumed regions, such as process chambers. Manual, pneumatic, electropneumatic, electrical, and electromagnetic methods can all be used to operate vacuum valves.
Where is the Toyota EGR valve located?
The EGR valve is situated in the back of the engine, just to the right of the center, as seen from the front. On a Toyota Lite Ace 5k engine, the piston ring and valve seals had to be replaced. Despite this, the engine still had high rpm and poor idling.
What location does the EGR valve have?
The primary goals of the exhaust gas recirculation valve, sometimes referred to as the EGR valve, are to lower combustion chamber temperatures and enhance emissions. Based on engine temperature, RPM, and other other engine characteristics, the EGR valve typically opens and closes. Unmetered air will be released into the engine if the valve sticks open, which will cause stalling and other symptoms resembling a vacuum leak. The combustion chambers may become hotter than anticipated if the valve becomes stuck in the closed position, which could lead to pre-ignition, in which the fuel begins to burn before the spark plug ignites.
Disconnecting the negative battery cable before starting is especially important if the EGR valve has an electrical hookup connected to it. A tube connecting the EGR valve to the exhaust manifold is typically found near or attached to the intake manifold. Additionally, a vacuum or electrical link (or both) should be running to the valve and must be disconnected. You must unplug the EGR valve from both the intake, where it is typically secured with multiple bolts, and the exhaust, where a pipe is typically threaded over or into it, in order to remove it. Be sure to save any gaskets when you remove the valve because they are frequently reusable and can be fairly pricey.
What exactly does EGR mean?
Exhaust Gas Recirculation (EGR) is a technique used in contemporary internal combustion engines to regulate Nitrogen Oxides (NOx) emissions, which are created as a byproduct during the combustion process.
When fuel and ambient air, which mostly contains an oxygen and nitrogen mixture, combine and ignite inside the combustion chamber, temperatures rise and NOx emissions are produced.
The EGR system reduces combustion temperatures and consequently lowers the quantity of NOx emitted by returning a small part of exhaust gas to the engine’s combustion chambers through the intake manifold.
The key element of the EGR system is the EGR valve, which is typically shut. It joins the intake and exhaust manifolds and is operated either by a vacuum or an internal electric step motor. Depending on the engine load, the EGR valve’s job is to regulate the flow of exhaust gas that is recirculated.
What is a solenoid valve for vacuum?
Vacuum solenoid valves, often referred to as electro-pneumatic pressure converters, electric switch over valves, or boost control solenoids, are used to regulate actuators in a number of engine systems, such as the variable geometry turbocharger, EGR valves, various bypass or throttle valves, etc.
What is the operation of a vacuum solenoid valve?
A solenoid valve regulates the flow of gases or liquids in either a positive, fully-closed, or fully-open mode. They are frequently used for remote control or to replace manual valves. When a solenoid valve operates, an orifice in the valve body is either opened or closed, allowing or preventing flow through the valve. By activating the coil, a plunger raises or lowers the aperture by elevating or lowering it within a sleeve tube.
An assembly of a coil, plunger, and sleeve makes up a solenoid valve. A plunger return spring maintains the plunger against the orifice in usually closed valves, blocking flow. The magnetic field that results from energizing the solenoid coil elevates the plunger, allowing flow. In a typically open valve, the plunger shuts the aperture when the solenoid coil is activated, obstructing flow.
A vacuum switch: how does it operate?
Vacuum switches, which offer control stability under variable conditions and guarantee continued operation even under extremely high shock and vibration, are corrosion-resistant and long-lasting. Vacuum pressure switches are frequently used to turn on and off waste oil heating systems, residential boilers, electric heaters, pumps, small air compressors, and transmission systems. They are also frequently used in applications as an interlock device to sense gas, air, or water pressure at a specific point.
Vacuum switches are used in the food processing, aerospace, chemical processing, heating and cooling, electronics, pharmaceutical, residential, industrial, and commercial sectors. The most prevalent kind of vacuum switches are used in automobiles to control the flow of engine fluid.
A change in negative pressure triggers a response from vacuum switches. When a change is detected, an elastomeric diaphragm activates the vacuum switch and opens or closes an electrical circuit based on a specified pressure set point. A single snap action switch, a mechanical switch that quickly switches contacts from one position to another, is activated by the movement of the diaphragm.
The snap action switch transforms the negative pressure indication into an electrical signal when it is activated. By separating pressure instruments from the process media while yet enabling the instruments to feel the process pressure, elastomeric diaphragms do away with the necessity for an oil barrier. An automated response point for a vacuum switch is set at a specific point of pressure. The vacuum pressure switch can be calibrated to the proper pressure points for opening and shutting the diaphragm using field changeable pressure set points.
Mechanical, pneumatic, and electrical vacuum switch designs are the three basic types. An elastomeric diaphragm responds to variations in pressure level in the mechanical and pneumatic variants, activating either a mechanical switch or a valve. The pressure level is determined using a piezoresistive pressure sensor in the electric version, which then translates the level into an electrical signal.
Vacuum switches come in a variety of materials, including cast aluminum, brass, polycarbonate, plated steel, glass-reinforced polyester, and polyvinyl chloride, depending on the use.
How much pressure is required for the vacuum valve to open?
A properly constructed vacuum truck tank in good condition can handle full vacuum, and unless a certified pressure vessel is legally limited to 14.9 PSI, we advise restricting your tank to no more than 89 PSI (see articles HERE and HERE for internal tank checks).
Your pressure relief valve defends your vacuum pump. The reason you need the vacuum relief is to let cool atmospheric air into the pump so that it can stay cool at greater vacuum levels. A vane pump is cooled by the air that goes through it.
Your vane pump will overheat if it doesn’t have a vacuum relief valve that works properly. Typically, we advise a vacuum relief valve to open at about 15 to 16 inches of mercury so that, when fully opened, the vacuum does not reach 18 to 20 inches.
Since a blower pump includes a ballast port to feed cooled air to the blower, it typically does not need a vacuum relief.
Having a vacuum truck tank that is properly engineered, constructed, and maintained is crucial.
Any owner of a vacuum truck should take the following action: routinely check the operation of their vacuum and pressure relief valves and set them to the right settings. For instructions on how to adjust your pressure relief valve and vacuum relief valve, respectively, see the videos located HERE and HERE.