Method for engine control

• US 6,067,489 A
• Filed: 06/04/1997
• Issued: 05/23/2000
• Est. Priority Date: 06/04/1997
• Status: Expired due to Term

• Current Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Original Assignee: Detroit Diesel Corporation (Daimler Truck Holding AG)
• Inventors: Babcock, Douglas J., Letang, Dennis M., Weisman, S. Miller II
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Application Number:
  US08/866,522
• Time in Patent Office: 1,084 Days
• Field of Search: 701/101, 701/99, 701/29, 701/36, 123/299, 123/436, 123/350, 123/488, 123/41.12, 123/322, 123/41.49, 123/41.19, 123/41.31, 123/41.44, 123/41.11, 123/41.08, 180/179, 417/292, 417/310, 417/214, 60/420, 60/456, 60/468, 60/484, 340/439, 340/441
• US Class Current: 701/36
• CPC Class Codes: F01P 2023/00 Signal processing; Details thereof
• CPC Class Codes: F01P 7/04 by varying pump speed, e.g. by changing pump-drive gear ratio
• CPC Class Codes: F01P 7/081 using clutches, e.g. electro-magnetic or induction clutches

Abstract

A method for comprehensive integrated control of compression-ignition internal combustion engine, wherein the control strategy integrates various functions of engine control with cooling fan control, and wherein the cooling fan control automatically ramps down cooling speed for multi-speed cooling fans whenever monitored engine conditions effecting cooling fan operation dictate transition of the multi-speed cooling fan from a high speed to an off condition.

Claims

1. A method of controlling a vehicle including an internal combustion engine having at least one engine driven multi-speed cooling fan assembly including a fan clutch and an engine driven multi-speed cooling fan that is turned on and turned off based on a current status of a pre-selected set of vehicle operating parameters and that has a low operating speed and a high operating speed, and an electronic control unit with memory for controlling the engine, the method comprising:

operating the at least on cooling fan at the high speed;

sensing the current status of the pre-selected set of vehicle operating parameters;

determining a desired fan condition for the at least one cooling fan based on the current status, the desired fan condition being turned off;

thereafter, while the desired fan condition is turned off, operating the at least one engine driven fan at the low speed for a pre-selected period of time; and

immediately after the pre-selected period of time, turning the at least one cooling fan off.

2. The method of claim 1 wherein the multi-speed fan is a two-speed fan.

3. The method of claim 1 wherein the pre-selected period of time is about 15 seconds.

4. A method of controlling a vehicle including an internal combustion engine having at least one engine driven multi-speed cooling fan assembly including a fan clutch and an engine driven multi-speed cooling fan that is turned on and turned off based on a current status of a pre-selected set of vehicle operating parameters and that has a low operating speed and a high operating speed, and an electronic control unit with memory for controlling the engine, the method comprising:

maintaining the at least one cooling fan in a turned off condition;

sensing the current status of the pre-selected set of vehicle operating parameters;

determining a desired fan condition for the at least one cooling fan based on the current status, the desired fan condition being turned on and operating at the high speed;

thereafter, while the desired fan condition is turned on and operating at the high speed, operating the at least one engine driven fan at the low speed for a pre-selected period of time; and

immediately after the pre-selected period of time, operating the at least one cooling fan at the high speed.

5. The method of claim 4 wherein the multi-speed fan is a two-speed fan.

6. The method of claim 4 wherein the pre-selected period of time is about 15 seconds.

7. A method of controlling a vehicle including a multi-cylinder internal combustion engine having at least one engine driven multi-speed cooling fan assembly including a fan clutch and an engine driven multi-speed cooling fan having low and high speeds and an electronic control unit with memory for controlling the engine, the method comprising:

operating the cooling fan at the high speed;

determining a desired vehicle road speed to obtain a desired road speed signal;

sensing at least one vehicle operating parameter to obtain an actual road speed signal;

comparing the desired road speed signal with the actual road speed signal;

determining a desired fan condition as turned off, based on the comparison;

thereafter, while the desired fan condition is turned off, operating the engine driven fan at the low speed for a pre-selected period of time; and

immediately after the pre-selected period of time, turning the cooling fan off.

8. A method of controlling road speed of a vehicle, including a multi-cylinder internal combustion engine having means for engine braking, a multi-speed cooling fan assembly including a fan clutch and an engine driven multi-speed cooling fan having low and high speeds, an electronic control unit with memory for controlling the engine, a plurality of sensors for sensing vehicle operating parameters, and means for indicating an overspeed condition, the method comprising:

determining a desired vehicle road speed to obtain a desired road speed signal;

sensing at least one vehicle operating parameter to obtain an actual road speed signal;

sensing the requested fueling level of the engine to obtain a requested fueling level signal;

evaluating a first comparison of the desired road speed signal to the actual road speed signal;

comparing the actual road speed signal to a first parameter stored in the memory associated with a non-zero fueling level request and a second parameter stored in the memory associated with a zero fueling level request;

initiating a variable time interval based upon at least one of the comparisons;

indicating an overspeed condition and storing at least one of the vehicle parameters in the memory when the variable time interval expires; and

,

modifying the engine braking based on the first comparison so as to control the road speed of the vehicle, wherein modifying the engine braking includes sensing a high fan speed request and operating the engine driven cooling fan at the high speed in response to the request, and sensing a turn off the fan request and in response thereto, operating the engine driven cooling fan at the low speed for a period of time, and immediately thereafter shutting off the engine driven cooling fan.

9. A system for controlling a vehicle including an internal combustion engine, the system comprising:

an engine driven multi-speed cooling fan assembly including an engine driven multi-speed cooling fan and a fan clutch, the fan having a low operating speed and a high operating speed; and

an electronic control unit including control logic operative to determine a current fan condition, to sense a current status of a set of vehicle operating parameters, and to control the fan based on the current status,

wherein upon the current fan condition being operating at the high speed and the desired fan condition based on the status being off,

the control logic is configured to control the fan by operating the fan at the low speed for a pre-selected period of time while the desired fan condition is turned off, and immediately thereafter, turning the fan off.