An assembly includes a thermocouple, a cold junction sensor, and a circuit. The thermocouple has a process end and a cold junction end. The cold junction end has first and second cold junction terminals. The cold junction sensor is supported near the cold junction end and configured to measure temperature at the cold junction end. The circuit is electrically connected to the cold junction sensor and to the first and second cold junction terminals. The circuit is configured to produce a thermocouple signal as a function of voltage across the first and second cold junction terminals and to produce a cold junction sensor signal as a function of temperature of the cold junction end as measured by the cold junction sensor. The circuit is further configured to calculate a correlation between the thermocouple signal and the cold junction sensor signal.

Thermocouple temperature sensor with connection detection circuitry

A microprocessor based system monitors and controls a transport refrigeration system having a two speed compressor coupled to a condenser and an evaporator and further having two speed condenser and evaporator fans, a refrigerant modulating valve, and heater means to cool or heat a served space. A keypad is provided for operator entry of the temperature setpoint and for display selections. Return air and discharge air temperature sensors provide signals to the microprocessor for temperature control. The microprocessor is programmed to sequence or control the compressor, the fans, the modulating valve and the heater means for temperature control in accordance with one of four stored algorithms. One of the temperature sensors is used for control, and if it is detected to have failed automatic switchover is made to use of the other temperature sensor for temperature control. Various input signals from the refrigeration system and from the microprocessor hardware are processed by the microprocessor to provide a data log and data for display and to detect system faults for fault history storage and for protective control action.

Microprocessor based control system and method providing better performance and better operation of a shipping container refrigeration system

Single shaft, air breathing auxiliary power units having a single stage centrifugal load compressor driven by a gas turbine engine. The latter has a single stage centrifugal compressor and a single stage radial inflow turbine mounted in back-to-back relationship on the same shaft as the load compressor. Control systems for these auxiliary power units feature turbine exhaust gas temperature and turbine speed responsive fuel flow control; a bypass valve control which causes air to be dumped overboard when the pneumatic load demand drops to prevent load compressor surge; and an inlet guide vane control.

Gas turbine engine/load compressor power plants

A magnetic path is formed by a vibrating member disposed in a housing in the radial direction and fixed at its end to the housing, a central magnetic path portion which is disposed to make a gap between the vibrating member and the central magnetic portion and to extend in the axial direction of the housing substantially at its center, a radial magnetic path portion extending from the central magnetic path portion in the radial direction of the housing with a predetermined spacing kept from the vibrating member, and an outer peripheral magnetic path portion extending from the outer peripheral side of the radial magnetic path portion toward the vibrating member. A permanent magnet for supplying magnetic flux to the magnetic path is disposed at the central magnetic path portion in the form of bar or at the outer peripheral magnetic path portion in the form of ring or to surround the central magnetic path portion. The outer peripheral magnetic path portion may be magnetically shielded by housing made of a magnetic material. The vibrating member and the central magnetic path portion may be assembled beforehand to be an integral structure.

Knock detecting apparatus for internal combustion engines

An ignition timing control system for internal combustion engines includes a knock detecting circuit for determining the presence or absence of the knocking in response to a signal from a knock detector, and includes a correction advance computing circuit for computing a correction value of ignition advance thereby to retard the ignition timing by a predetermined angle when the knock is present and to advance the ignition timing when the knock is absent. A further battery is provided to supply electric power to the correction advance computing circuit even after a key switch associated with a main battery for supplying power to the ignition timing control system has been turned off. Hence, the correction advance computing circuit memorizes the computed advance correction value corresponding to a knock condition of the engine just prior to the turn-off of the key switch and the memorized advance correction value is made available in a subsequent operation of the ignition timing control system.

Ignition timing control system for internal combustion engines

A vibration sensor mounted on an internal combustion engine characterized by knock-induced vibrations at a characteristic frequency and by other vibrations is tuned to resonate at substantially the characteristic frequency. A bandpass filter tuned to the characteristic frequency is connected to the vibration sensor output; and the output of the filter is provided to one input of a comparator and to average detector circuitry for generating a unidirectional noise reference signal representing noise at the characteristic frequency, which signal is provided to the other input of the comparator. The knock signal, obtained from the output of the comparator and comprising pulses corresponding to knock-induced peaks of amplitude greater than the unidirectional noise reference signal, is fed back through a low-pass filter to the average detector circuitry in sense to oppose increases in the unidirectional noise reference signal during said knock-induced peaks. The connection of the average detector circuitry to the output of the bandpass filter provides adaptability for mistuned sensors; and the negative feedback to the average detector circuitry reduces the distorting effect, amplified by the bandpass filter, of said knock-induced peaks on the unidirectional noise reference signal, which might otherwise distort the output knock signal.

Engine knock signal generating apparatus with noise channel inhibiting feedback

In a spark timing system for a spark ignited internal combustion engine, means are provided for generating a series of alternating coil-on and coil-off signals in accordance with crankshaft rotation and one or more engine operating conditions, means are provided for normally passing each coil-on signal immediately to the spark coil to turn on current therethrough and means are provided for passing each coil-off signal to the spark coil to turn off current therethrough with a retard determined in accordance with an additional engine operating condition to generate a spark pulse retarded with respect to the normal spark timing. To ensure a minimum burn time for the spark plugs, means are provided to hold the spark coil in the off condition for a predetermined minimum burn time following each retarded coil-off signal, regardless of the possible appearance of a coil-on signal before the end of this minimum burn time.

Engine spark timing system with retard means and minimum burn timer

A circuit is provided for detecting an open condition in a thermocouple or thermocouple leads connected to a preamplifier even though the thermocouple is grounded or connected to ground through some resistance. A high frequency AC test signal is applied to both leads of the thermocouple and one of the leads is connected to a low pass filter. When the thermocouple circuit is closed, the AC signal on both leads will be substantially equal. If, however, either of the leads or the thermocouple itself is open, the AC signal will be different due to the low pass filter connected to one of the leads. That filter attenutes the signal on the associated lead as well as causing a phase shift of the two AC signals. A differential amplifier connected to the thermocouple leads detects the amplitude attenuation or the phase shift to provide an output whenever the thermocouple circuit is opened.

Thermocouple failure detector

An engine spark timing system includes pulse generating apparatus effective to generate conventional spark timing pulses, apparatus, including a first capacitor, effective to vary the voltage across the first capacitor in one direction at a first rate toward a reference voltage and generate a retarded spark timing pulse when the first voltage is reached, apparatus initiated at the time the retarded spark timing pulse is generated to vary the voltage across the capacitor in the opposite direction at a second rate until the next conventional spark timing pulse and apparatus responsive to engine start and one or more other engine operating conditions to substitute selected retarded spark timing pulses for the corresponding conventional spark timing pulses in the firing of the engine spark plugs. In order that the capacitor voltage not reach its maximum value and clip during the slower engine speeds typical of engine start, apparatus responsive to the actuation of engine cranking means is effective to insert a second capacitor parallel with the first capacitor to slow the rates of voltage change across the capacitor in both directions in the same proportion.

Engine spark timing system and method with supplementary retard in normal and starting modes

An electronic circuit is used to control a gas turbine engine primarily as a function of turbine inlet temperature and compressor speed and in particular includes a speed governing loop to control compressor speed according to throttle position and modified by a temperature limiting compensation loop which accurately sets the turbine inlet temperature limit according to a schedule which avoids engine surge and destructive temperatures. The compensation loop is particularly designed to provide quick response to acceleration demands and a smooth transition to temperature limiting. A start fuel schedule circuit is also used to moderate the speed loop during engine starting.

Gene A. West

Papers

Engine knock signal generating apparatus with noise channel inhibiting feedback

Engine spark timing system with retard means and minimum burn timer

Thermocouple failure detector

Engine spark timing system and method with supplementary retard in normal and starting modes

Gas turbine engine fuel control