초록 ▼

Electronic control apparatus is disclosed for automatically controlling the operation of refrigeration units on truck-drawn trailers and providing a signal to the truck driver in the event there is a malfunction in the refrigeration unit that could result in damage to the cargo. An electronic automa

Electronic control apparatus is disclosed for automatically controlling the operation of refrigeration units on truck-drawn trailers and providing a signal to the truck driver in the event there is a malfunction in the refrigeration unit that could result in damage to the cargo. An electronic automatic temperature control circuit includes solid state comparators which are responsive to a temperature sensor and to a temperature selector. The comparators provide output signals that selectively actuate solid state control elements which in turn control the actuation of the various load devices in the refrigeration unit to maintain the temperature in the refrigerated chamber within a selected temperature range. When the temperature in the refrigerated chamber is above a selected temperature setting to the extent that damage to the cargo might be caused, a solid state malfunction circuit controls the actuation of a solid state relay and in turn a malfunction indicator. A solid state defrost cycle control circuit is responsive to a defrost cycle sensor indicating defrosting is taking place, which overrides the actuation of the malfunction circuit for a few minutes during each multiple-hour time interval and, if the defrost cycle sensor fails, the defrost cycle control circuit is arranged to insure that the defrosting operation is still carried out.

대표청구항 ▼

In refrigerator electronic control apparatus for controlling the temperature in and providing a malfunction signal for a refrigeration unit associated with a refrigerated chamber, the combination comprising: temperature sensor means for said chamber; temperature selector means for said chamber havin

In refrigerator electronic control apparatus for controlling the temperature in and providing a malfunction signal for a refrigeration unit associated with a refrigerated chamber, the combination comprising: temperature sensor means for said chamber; temperature selector means for said chamber having a range of temperature settings; and electronic circuit means including: temperature reference means operatively associated with said temperature selector, said temperature reference means establishing a plurality of temperature reference points at selected temperature increments above and below a set point, a comparator associated with each of said temperature reference points, each comparator responsive to an output of the associated set point and to an output of said temperature sensor means, and control means including a plurality of solid state control elements, each control element responsive to an output of one of said comparators for alternately effecting the actuation of a heat load device in said refrigeration unit when the temperature in said chamber is a selected temperature increment below said set point and effecting the actuation of a cool load device in said refrigeration unit when the temperature in said chamber is a selected temperature increment above said set point to automatically maintain the temperature in said chamber within a selected temperature range and for also effecting the actuation of a malfunction indicator and disabling a prime mover load device to stop said refrigeration unit in the event of a malfunction in said refrigeration unit when the temperature in said chamber exceeds a selected maximum temperature reference point above said set point.