US-20260126061-A1 - PNEUMATIC SYSTEM

US20260126061A1US 20260126061 A1US20260126061 A1US 20260126061A1US-20260126061-A1

Abstract

A pneumatic system has first and second electrically operated air dryers, each couplable to a compressor through a selection valve. The selection valve is a pneumatically controlled valve, and a fluid pressure at an output port of a governor valve of one of the electrically operated air dryers is used to control switching of the selection valve.

Inventors

Georg Frank

Assignees

AGCO INTERNATIONAL GMBH

Dates

Publication Date: 20260507
Application Date: 20251105
Priority Date: 20241106

Claims (13)

1 . A pneumatic system, comprising: a compressor; a selection valve; a first electrically operated air dryer (EOD) and a second EOD, each EOD having an input fluidly couplable to the compressor through the selection valve and an output configured to be fluidly connected to at least one consumer; each EOD comprising: a dryer unit; a discharge valve for selectively coupling the EOD input to atmosphere; and a governor valve having an output port fluidly connected to a control pilot port of the discharge valve, the governor valve being selectively operable in an EOD inlet venting configuration to fluidly connect the output port to the EOD output so as to actuate the discharge valve to fluidly connect the EOD input to atmosphere; wherein the selection valve is a pneumatically controlled valve having a pilot port for receiving a control pressure signal and is operative to connect either the first EOD or the second EOD to the compressor, the selection valve being biased to connect one of the first and second EODs to the compressor and being movable against the bias in response to a control pressure signal at the selection valve pilot port to connect the other of the first and second EODs to the compressor, and wherein the control pressure signal is derived from the fluid pressure at the output port of the governor valve said one of the first and second EODs when the governor valve is operative in said EOD inlet venting configuration.
2 . The pneumatic system of claim 1 , wherein the output port of the governor valve of said one of the first and second EODs is fluidly connected directly to the selection valve pilot port, the fluid pressure at the output port when the governor valve is operative in said EOD inlet venting configuration comprising the control pressure signal.
3 . The pneumatic system of claim 1 , wherein the system comprises a further pneumatically piloted valve, the output port of the governor valve of said one of the first and second EODs is fluidly connected to a pilot port of the further pneumatically piloted valve, such that when the governor valve is operative in said EOD inlet venting configuration, the further pneumatically piloted valve is actuated to connect a source of fluid pressure to the selection valve pilot port to constitute the control pressure signal.
4 . The pneumatic system of claim 1 , wherein each EOD also has: a one-way output valve between an output of the dryer unit and the output of the EOD, the one-way output valve configured to allow air to pass only in the first direction from the dryer unit to the EOD output; and a regeneration valve connected in parallel to the one-way output valve between the dryer unit output and the EOD output and selectively operable for bypassing the one-way output valve to allow air to flow in a second direction opposite to the first from the EOD output through the dryer unit.
5 . The pneumatic system of claim 1 , wherein each EOD has (i) a loading mode in which air from the compressor is driven through the EOD to the at least one consumer and (ii) a non-loading mode in which the EOD inlet is fluidly connected to the atmosphere by the discharge valve, wherein the compressor has an idle mode which is triggered by a pressure to an idle control port of the compressor.
6 . The pneumatic system of claim 5 , wherein the pneumatic system comprises a pneumatic control valve having an output fluidly connected to the idle control port, for placing the compressor into the idle mode when both the first and second EODs are in the non-loading mode.
7 . The pneumatic system of claim 6 , wherein the pneumatic control valve is a pneumatic logic AND valve having two inlet ports, each fluidly connected to the output port of a governor valve of a respective one of the first and second EODs, and an output port fluidly connected to the compressor idle control port.
8 . The pneumatic system of claim 5 , comprising a compressor mode selection valve for selectively providing a system pressure to the idle control port of the compressor, wherein the compressor mode selection valve is electrically actuated by a control unit.
9 . The pneumatic system of claim 8 , wherein the system pressure comprises the pressure at the output port of a governor valve of one of the first and second EODs.
10 . The pneumatic system of claim 8 , wherein the system pressure comprises the pressure at the at least one consumer.
11 . A vehicle comprising: the pneumatic system of claim 1 ; and the at least one consumer that is supplied by the pneumatic system.
12 . The vehicle of claim 11 , wherein the at least one consumer comprises at least one selected from the following list: rear service brake; front service brake; park brake; trailer brake. tire pressure control system; cab air supply; dust discharge system.
13 . The vehicle of claim 11 , comprising an agricultural vehicle, or a combination of a towing agricultural vehicle and a towed implement.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims the benefit of the filing date of U.K. Patent Application 2416369.3, “PNEUMATIC SYSTEM”, filed Nov. 6, 2024, the entire disclosure of which is incorporated herein by reference. FIELD Embodiments of the present disclosure relate generally to pneumatic systems, such as pneumatic supply systems, especially for industrial or utility vehicles, such as tractors, other agricultural vehicles, construction vehicles and others. BACKGROUND Vehicle air supply systems require air dryers to discharge humidity from the air before supplying it to consumers (i.e., on-board or external equipment requiring a pneumatic supply such as pneumatic actuators, pneumatic cylinders, pneumatic motors and reservoirs or accumulators for storing a pressurized air supply for such equipment). Damp air can cause corrosion in pipes and other components on the vehicle, so before supplying air to consumers (for example, for the vehicle's brake system) the air is usually guided through a dryer. When the air is passing through the dryer to dry the air, this mode of operation is known as a drying or loading mode. Due to the restricted load capacity of dryers, a second operation mode, known as a regeneration mode, is required which involves passing air through the reservoir in an opposite direction and discharging it to the atmosphere to remove water deposited in, or on, the drying material of the dryer. It is known to use double chamber dryers which comprise two separate dryer reservoirs, so that when one chamber is operative in drying the air from the compressor in a loading mode, the other chamber can be operated in a regeneration mode. The shift between the two modes of each drying chamber is time-controlled, so that the dryer may continually be used to dry air. Furthermore, Electrically Operated Air Dryers (EODs) are also known. These dryers only require one dryer portion and the shift between the two modes of operation, that is the switch between the regeneration mode and the loading mode, is controlled electronically. This may be time-controlled by a control unit. For example, the two modes can be controlled by measuring the volume of air passing through the dryer by measuring the compressor time or measuring the pressure rise in the reservoirs (and knowing that a certain pressure rise requires a predetermined air volume). A percentage of the volume of air in the air supply system can be guided back for the regeneration. Known pneumatic supply systems also have a compressor idle mode, used when the compressor is not required to supply compressed air through the dryer. The idle mode conserves energy and hence reduces power consumption. The idle mode is used when the air pressure in the system is within the desired range. Moisture sensing may also be used. It is known to use two EODs connected in parallel in a pneumatic supply system so that the EODs can be used alternately, with one operating in a loading mode and the other in a regenerating or other non-loading mode. The EODs are typically connected with a single compressor through a pneumatically controlled selection valve. Actuation of the selection valve is regulated electronically using a solenoid actuated valve to selectively connect a pneumatic pilot port of the selection valve to a source of fluid pressure to move the valve and switch between the EODs. However, this adds complication to control of the overall system. BRIEF SUMMARY The scope of this disclosure is defined by the claims. According to examples in accordance with this disclosure, there is provided a pneumatic system, comprising: a compressor;a selection valve;a first and a second electrically operated air dryer (EOD), each EOD having an input fluidly couplable to the compressor through the selection valve and an output configured to be fluidly connected to at least one consumer;each EOD comprising:a dryer unit;a discharge valve for selectively coupling the EOD input to atmosphere; anda governor valve having an output port fluidly connected to a control pilot port of the discharge valve, the governor valve being selectively operable in an EOD inlet venting configuration to fluidly connect the output port to the EOD output so as to actuate the discharge valve to fluidly connect the EOD input to atmosphere;wherein the selection valve is a pneumatically controlled valve having a pilot port for receiving a control pressure signal and is operative to connect either the first EOD or the second EOD to the compressor, the selection valve being biased to connect one of the first and second EODs to the compressor and movable against the bias in response to a control pressure signal at the selection valve pilot port to connect the other of the first and second EODs to the compressor, and wherein control pressure signal is derived from the fluid pressure at the output port of the governor valve of said one of the first and second EODs when the governor valve is operative in