Method for controlling a hydraulically-actuated fuel injections system to start an engine

• US 5,447,138 A
• Filed: 07/29/1994
• Issued: 09/05/1995
• Est. Priority Date: 07/29/1994
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Barnes, Travis E.
• Primary Examiner(s): Moulis, Thomas N.
• Application Number:
  US08/282,840
• Time in Patent Office: 403 Days
• Field of Search: 123/446, 123/496, 123/179.17, 123/458
• US Class Current: 123/446
• CPC Class Codes: F02M 57/025 hydraulic, e.g. with pressure amplification
• CPC Class Codes: F02M 59/105 hydraulic drive F02M59/32 takes precedence

Abstract

In one aspect of the present invention, a method is disclosed that controls the pressure of actuating fluid supplied to a hydraulically-actuated injector. A target engine speed acceleration is determined, and compared to the actual engine speed acceleration to determine a desired actuating fluid pressure in order to control the fuel injection rate to start the engine.

Claims

1. A method for controlling a hydraulically-actuated injector (25) to start an internal combustion engine (55), comprising the steps of:

determining an actual acceleration rate of the engine, comparing the acceleration rate to a target acceleration rate, and producing an acceleration rate error signal ds_e in response to the comparison;

receiving the acceleration rate error signal ds_e, and producing a desired actuating fluid pressure signal (P_d); and

receiving the desired actuating fluid pressure signal (P_d), determining a desired electrical current, and producing a desired electrical current signal (I) to control the fuel injection rate.

2. A method, as set forth in claim 1, including the steps of:

sensing the temperature of the engine and producing a engine temperature signal (T_c) indicative of the temperature of actuating fluid used to hydraulically actuate the injector (25);

sensing the engine speed and producing an engine speed signal (s_f) indicative of the sensed engine speed; and

receiving the engine speed and temperature signals (s_f,T_c), determining the target acceleration rate based on the magnitude of the engine speed and temperature signals, and producing a target acceleration rate signal (ds_t) indicative of the target acceleration rate.

3. A method, as set forth in claim 2, including the steps of receiving the engine speed signal (s_f), determining the actual engine acceleration rate in response to differentiating the engine speed signal, and producing an actual engine acceleration rate signal (ds_f) indicative of the actual acceleration rate.

4. A method, as set forth in claim 3, including the steps of receiving the target and actual acceleration rate signals (ds_t,ds_f), and producing the acceleration rate error signal (ds_e) in response to the difference between the target and actual acceleration rate signals (ds_t,ds_f).

5. A method, as set forth in claim 4, including the steps of:

sensing an actual actuating fluid pressure and producing an actual actuating fluid pressure signal (P_f) indicative of sensed actuating fluid pressure;

comparing the desired actuating fluid pressure signal (P_d) with the actual actuating fluid pressure signal (P_f) and producing an actuating fluid pressure error signal (P_e) in response to a difference between the compared actuating fluid pressure signals (P_df,P_f); and

receiving the actuating fluid pressure error signal (P_e), determining the desired electrical current based on the actuating fluid pressure error signal (P_e), and producing the desired electrical current signal (I).

6. A method, as set forth in claim 5, wherein the desired fluid pressure is determined to cause the fuel injector (25) to produce a plurality of injections during an injection period.