Electronic controls for compression release engine brakes

• US 5,967,115 A
• Filed: 02/11/1998
• Issued: 10/19/1999
• Est. Priority Date: 10/07/1994
• Status: Expired due to Term

• Current Assignee: Diesel Engine Retarders, Inc. (Cummins Incorporated)
• Original Assignee: Diesel Engine Retarders, Inc. (Cummins Incorporated)
• Inventors: Konopka, John, Mercier, Real, Hu, Haoran
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US09/022,026
• Time in Patent Office: 615 Days
• Field of Search: 123/90.11, 123/321, 123/322, 123/323, 123/90.15, 123/568.14
• US Class Current: 123/322
• CPC Class Codes: F01L 13/06 for braking
• CPC Class Codes: F01L 2201/00 Electronic control systems; Apparatus or methods therefor
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: F02D 13/04 using engine as brake

Abstract

Electronic controls for compression release engine retarders of internal combustion engines which provide electronic signals to control hydraulic valves assembled in the hydraulic actuators of the retarders, to open engine exhaust valves to provide compression release events. The electronic controls may produce signals for both opening and/or closing the controlled valves. The electronic controls may monitor various engine operating conditions and/or parameters with one or more sensors distributed in the engine and vehicle in which the engine is installed. The timing of valve actuation, particularly that for compression release events, can be automatically modified responsive to the level of engine operating conditions and parameters. Various operating routines for the electronic controls are also disclosed.

Claims

1. A method of controlling a means for selectively actuating a valve, said valve providing communication between an internal combustion engine exhaust manifold and a cylinder, so that a desired predetermined compression release valve event may be achieved, the method comprising the steps of:

sensing, during engine braking, one or more engine parameters selected from the group consisting of;

a cylinder temperature, an exhaust manifold pressure, and the pressure of a hydraulic source in communication with said means for selectively actuating the valve;

determining, for an engine exhibiting the one or more of said sensed engine parameters, one or more desired valve event parameters selected from the group consisting of;

a valve opening time, a valve closing time, and a valve lift; and

actuating said valve in accordance with said one or more valve event parameters.

2. The method of claim 1 further comprising the step of sensing one or more engine parameters selected from the group consisting of:

engine speed, vehicle speed, clutch position, turbo charger boost pressure, fuel pump actuation, camshaft position, gas pressure in a cylinder of said engine, gas pressure in an intake manifold of said engine, ambient air temperature, and ambient barometric pressure.

3. A method of controlling a means for selectively actuating a valve, said valve providing communication between an internal combustion engine exhaust manifold and a cylinder, so that a desired predetermined valve event may be achieved, the method comprising the steps of:

providing an internal combustion engine including a control module operatively connected to one or more engine parameter sensors and to the means for selectively actuating a valve;

applying a retarder request signal to the control module;

monitoring with the sensors, one or more parameters selected from the group consisting of;

fuel supply status, clutch status, transmission status, and engine speed;

activating a retarder main control responsive to the level of the one or more monitored parameters and the retarder request signal;

determining one or more conditions selected from the group consisting of;

camshaft position, crankshaft position, engine speed, engine cylinder pressure, turbo charger boost pressure, vehicle speed control setting, vehicle speed, ambient air temperature, and ambient barometric pressure, responsive to the activation of the retarder main control;

determining a retarding torque requirement responsive to the level of the one or more determined conditions;

determining the number of engine cylinders to be used for compression release retarding events responsive to the level of the determined retarding torque requirement;

determining the times at which an exhaust valve should be opened and closed in each of the engine cylinders to be used to achieve the desired valve event; and

opening and closing an exhaust valve at the determined times.

4. The method of claim 3 wherein the step of determining the number of engine cylinders to be used further comprises the step of:

determining the thermal loading of one or more of the engine cylinders.

5. The method of claim 4 wherein the step of determining the number of engine cylinders to be used further comprises the step of:

regulating exhaust back pressure in the engine.

6. The method of claim 4 wherein the step of determining the number of engine cylinders to be used further comprises the step of controlling the opening and closing of exhaust valves for exhaust gas recirculation for one or more of the cylinders to be used.

7. The method of claim 3 wherein the step of determining the number of engine cylinders to be used further comprises the step of:

regulating exhaust back pressure in the engine.

8. The method of claim 7 wherein the step of determining the number of engine cylinders to be used further comprises the step of controlling the opening and closing of exhaust valves for exhaust gas recirculation for one or more of the cylinders to be used.

9. The method of claim 3 wherein the times which the exhaust valve should be opened and closed are determined as a function of instantaneous engine speed and instantaneous engine position.

10. The method of claim 9 wherein the instantaneous engine positions are determined as a function of camshaft position and crankshaft position.

11. A method of determining the opening and closing times of a trigger valve in an internal combustion engine to carry out a desired level of compression release braking, the method comprising the steps of:

determining engine operation status;

determining engine position;

synchronizing a trigger valve controller with engine position;

determining the advisability of compression release braking;

determining trigger valve opening and closing times, responsive to engine position, said times determined such that they provide a desired compression release braking event;

storing the trigger valve opening and closing times in a memory;

reading the trigger valve opening and closing times from the memory and generating trigger valve actuation signals related to the read trigger valve times; and

applying the trigger valve actuation signals to the trigger valve to actuate the trigger valve;

wherein the steps of determining engine operation status, determining engine position, and synchronizing a trigger valve controller comprise the steps of;

detecting the periodic occurrence of plural first engine events and the occurrence times thereof, said first engine events also being used to indicate times for trigger valve actuation;

determining an assumed engine position given the existence of a predetermined relationship between the occurrence times of the first engine events and the position of the engine;

detecting the cyclical occurrence of a second engine event and the occurrence time thereof;

determining an actual engine position given the existence of a predetermined relationship between the occurrence time of the second engine event and the position of the engine; and

synchronizing the trigger valve controller by comparing the assumed and actual engine positions for a match.

12. The method of claim 11 wherein the plural first engine events comprise the passage of timing gear teeth past a fixed point.

13. The method of claim 11 wherein the second engine event comprises a complete revolution of a crankshaft.

14. A method of determining the opening and closing times of a trigger valve in an internal combustion engine to carry out a desired level of compression release braking, the method comprising the steps of:

determining engine operation status;

determining engine position;

synchronizing a trigger valve controller with engine position;

determining the advisability of compression release braking; and

determining trigger valve opening and closing times, responsive to engine position, said times determined such that they provide a desired compression release braking event;

wherein the step of determining the advisability of compression release braking comprises the steps of;

determining engine speed to be within a predetermined range of speeds;

detecting a compression release braking request signal; and

determining the status of a compression release braking driver switch.

15. A method of determining the opening and closing times of a trigger valve in an internal combustion engine to carry out a desired level of compression release braking, the method comprising the steps of:

determining engine operation status;

determining engine position;

synchronizing a trigger valve controller with engine position;

determining the advisability of compression release braking;

determining trigger valve opening and closing times, responsive to engine position, said times determined such that they provide a desired compression release braking event;

storing the trigger valve opening and closing times in a memory;

reading the trigger valve opening and closing times from the memory and generating trigger valve actuation signals related to the read trigger valve times; and

applying the trigger valve actuation signals to the trigger valve to actuate the trigger valve;

wherein the steps of determining and storing trigger valve opening and closing times comprises the steps of;

reading the trigger valve opening and closing times from a look-up table;

determining instantaneous engine speed;

modifying the opening and closing times responsive to the determined engine speed;

determining the availability of a memory storage location for the opening and closing times; and

storing the opening and closing times in the memory storage location responsive to the availability thereof.

16. The method of claim 15 further comprising the step of determining the availability of a second memory location for the opening and closing times responsive to the availability of the memory storage location.

17. A method of determining the opening and closing times of a trigger valve in an internal combustion engine to carry out a desired level of compression release braking, the method comprising the steps of:

determining engine operation status;

determining engine position by detecting the cyclical occurrence of an engine event and the occurrence time thereof, and determining an actual engine position given the existence of a predetermined relationship between the occurrence time of the engine event and the position of the engine; and

synchronizing a trigger valve controller with engine position by determining an assumed engine position given the existence of a predetermined relationship between the passage times of the timing gear teeth and the position of the engine, and by comparing the assumed and actual engine positions for a match;

determining the advisability of compression release braking by determining engine speed to be within a predetermined range of speeds, detecting a compression release braking request signal, and determining the status of a compression release braking driver switch; and

determining trigger valve opening and closing times, responsive to engine position, said times determined such that they provide a desired compression release braking event by reading the trigger valve opening and closing times from a look-up table, determining engine speed, and modifying the opening and closing times responsive to the determined engine speed.

18. The method of claim 17 further comprising the steps of:

storing the trigger valve opening and closing times in a memory by determining the availability of a memory storage location for the opening and closing times, and storing the opening and closing times in the memory storage location responsive to the availability thereof;

reading the trigger valve opening and closing times from the memory and generating trigger valve actuation signals related to the read trigger valve times; and

applying the trigger valve actuation signals to the trigger valve to actuate the trigger valve.

19. An apparatus for determining the opening and closing times of a trigger valve in an internal combustion engine to carry out a desired level of compression release braking, the apparatus comprising:

a first sensor for sensing the passage of teeth on a gear, said first sensor being operatively connected to an engine timing gear;

a second sensor for sensing the rotation of an engine component selected from the group consisting of;

a crankshaft and a camshaft; and

computing means for;

determining engine operation status operatively connected to the first sensor;

determining engine position operatively connected to the second sensor;

synchronizing a trigger valve controller with engine position;

determining the advisability of compression release braking; and

determining trigger valve opening and closing times responsive to engine position, said times determined such that they provide a desired compression release braking event.

20. The apparatus of claim 19 wherein said computing means further comprises means for:

storing the trigger valve opening and closing times in a memory;

reading the trigger valve opening and closing times from the memory and generating trigger valve actuation signals related to the read trigger valve times; and

applying the trigger valve actuation signals to the trigger valve to actuate the trigger valve.

21. The apparatus of claim 19 further comprising a sensor operatively connected to the computing means, said sensor being capable of sensing an engine parameter selected from the group consisting of:

cylinder temperature, exhaust manifold pressure, engine speed, vehicle speed, clutch position turbo charger boost pressure fuel pump actuation, camshaft position, gas pressure in a cylinder of said engine, gas pressure in an intake manifold of said engine, ambient air temperature, and ambient barometric pressure.

22. The method of controlling a compression release engine brake of the type having an electrically operated hydraulic valve for selectively applying high pressure hydraulic fluid to a hydraulic actuator which responds to the application of said high pressure hydraulic fluid by opening a valve in an internal combustion engine associated with said engine brake to produce a compression release event in said engine, said method comprising the steps of:

monitoring the internal motion of said engine to detect the progress of the engine cylinder served by said valve in said engine through the cycle of operation of said engine cylinder;

monitoring at least one other operating condition of said engine, wherein said one other operating condition is selected from the group consisting of;

cylinder temperature, exhaust manifold pressure, vehicle speed, fuel pump actuation, gas pressure in a cylinder of said engine, ambient air temperature, and ambient barometric pressure; and

applying an electrical signal to said hydraulic valve to open said hydraulic valve at a time based at least in part on said progress of said engine cylinder and said other operating condition of said engine.