Diesel engine secondary fuel injection system

• US 4,953,515 A
• Filed: 11/28/1988
• Issued: 09/04/1990
• Est. Priority Date: 11/28/1988
• Status: Expired due to Fees

• Current Assignee: Brian G. Buck, William A. Fehr
• Original Assignee: Brian G. Buck, William A. Fehr
• Inventors: Buck, Brian G., Fehr, William A.
• Primary Examiner(s): Miller, Carl S.
• Application Number:
  US07/277,083
• Time in Patent Office: 645 Days
• Field of Search: 123/525, 123/383, 123/387, 123/526, 123/494
• US Class Current: 123/526
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 7/06 the fuel in the charge being gaseous
• CPC Class Codes: F02D 19/0631 by estimation, i.e. without using direct measurements of a corresponding sensor
• CPC Class Codes: F02D 19/10 peculiar to compression-ignition engines in which the main fuel is gaseous
• CPC Class Codes: F02D 23/02 the engines being of fuel-injection type
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02M 21/0278 Port fuel injectors for single or multipoint injection into the air intake system
• CPC Class Codes: F02M 21/0284 Arrangement of multiple injectors or fuel-air mixers per combustion chamber
• CPC Class Codes: F02M 21/042 Mixer comprising a plurality of bores or flow passages
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A method of operating a diesel engine. Diesel fuel is controllably injected into the engine. An engine performance parameter such as turbo-charger boost pressure, fuel pressure in the diesel fuel injector galleries, or air intake manifold pressure, or a combination of such parameters, is monitored. A secondary fuel such as propane is injected into the engine in an amount which varies as a function of the monitored parameter(s).

Claims

1. A method of operating a turbo-charged diesel engine, comprising the steps of:

(a) controllably injecting pressurized diesel fuel into said engine;

(b) coupling a plurality of pressure sensors to said engine turbo-charger, said sensors for sensing the boost pressure output of said engine turbo-charger;

(c) coupling an equal plurality of normally closed valves between said engine and a secondary fuel reservoir, said valves being openable in response to applied signals to allow said secondary fuel to flow to said engine;

(d) adjusting each of said sensors to detect a selected turbo-charger boost pressure within a pressure range, such that each of said sensors produces an output signal when said engine turbo-charger boost pressure is increased to said corresponding selected boost pressure, and such that said plurality of sensors together produce a plurality of output signals distributed within said pressure range; and

,

(e) applying said output signals to corresponding ones of said valves,

3. A method as defined in claim 1 or 2, wherein said secondary fuel is propane.

2. Apparatus for supplying a secondary fuel to a turbo-charged diesel engine, said apparatus comprising:

(a) a plurality of adjustable pressure sensors coupled to said engine turbo-charger, said sensors for sensing the boost pressure output of said engine turbo-charger and for respectively producing an equal plurality of output signals representative of said boost pressure; and

,

(b) an equal plurality of normally closed valves coupled between said engine and a secondary fuel reservoir, said valves being electrically connected to corresponding ones of said pressure sensors for opening of said valves in response to said corresponding pressure sensor output signals to allow said secondary fuel to flow to said engine;

whereby adjustment of said sensors to detect selected turbo-charger boost pressures distributed within a pressure range causes said respective sensors to produce corresponding output signals when said engine turbo-charger boost pressure is increased to said corresponding selected boost pressures, thereby sequentially opening said valves as said engine turbo-charger boost pressure increases.