ENGINE COOLING SYSTEM CONTROL
First Claim
Patent Images
1. A diagnostic method comprising:
- adjusting a state of one or more cooling system valves to stagnate a first amount of coolant in a first loop while circulating a second amount of coolant at a thermostat in a second loop; and
indicating thermostat degradation based on a difference between a coolant temperature and a threshold, the threshold based on the state of the valves.
1 Assignment
0 Petitions
Accused Products
Abstract
Methods and systems are provided for diagnosing each of a plurality of engine cooling system components including various valves and grill shutters. Each valve may be individually closed and opened for a specified duration, and corresponding changes in coolant temperature may be monitored. If all the components are functional, the various valves may be adjusted to stagnate coolant at the engine and expedite engine warm-up during a cold-start.
-
Citations
20 Claims
-
1. A diagnostic method comprising:
-
adjusting a state of one or more cooling system valves to stagnate a first amount of coolant in a first loop while circulating a second amount of coolant at a thermostat in a second loop; and indicating thermostat degradation based on a difference between a coolant temperature and a threshold, the threshold based on the state of the valves. - View Dependent Claims (2, 6, 7, 8, 9)
-
- 3. The method of claim 3, wherein the cabin heat loss estimated is based on each of a cabin heater fan speed, a cabin air temperature, and a coolant pump speed.
-
10. A method for a vehicle cooling system, comprising:
-
during an engine cold start, adjusting a plurality of valves to vary a first amount of coolant stagnated in a first loop of the cooling system while circulating a second amount of coolant in a second loop including a thermostat; comparing an estimated coolant temperature profile sensed at the thermostat with an expected coolant temperature profile over a duration; and indicating thermostat degradation based on a difference between the estimated temperature profile and the expected temperature profile being larger than a threshold amount. - View Dependent Claims (11, 12, 13, 14, 15, 16)
-
-
17. A vehicle system, comprising:
-
an engine; a transmission; a passenger cabin; an engine cooling system communicatively coupled to each of the engine, transmission, and cabin, the cooling system including a plurality of valves, a heater core, a radiator, and a thermostat; a grill shutter system; and a controller with computer readable instructions for; adjusting the plurality of valves to stagnate a first amount of coolant at a first temperature in a first loop of the cooling system while circulating a second amount of coolant at a second, different temperature in a second loop of the cooling system; estimating a coolant temperature at the thermostat over a duration; and indicating thermostat degradation based on a rate of change in the estimated coolant temperature over the duration relative to an expected rate of change, the expected rate of change based on engine operating conditions and a state of the plurality of valves. - View Dependent Claims (18, 19, 20)
-
Specification