US3626918A

US3626918A - Starting system for diesel engines

Info

Publication number: US3626918A
Application number: US842901A
Authority: US
Inventors: Arthur M Brenneke
Original assignee: TRW Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1969-07-18
Filing date: 1969-07-18
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14
Also published as: FR2055317A5; DE2031925A1; CH507447A

Abstract

A starting system for diesel engines which sequentially provides pressured gas directly to the cylinders to initiate engine turnover. The gas is supplied either from a compressed air storage or from a chemical pressure generator capable of supplying high-pressure, high-temperature gases. The chemical pressure generator supplied gases initiate engine turnover while heating the engine to a point necessary for combustion in lowtemperature environments.

Description

United States Patent 1,919,348 7/1933 Tibbetts 123/179 1,935,123 11/1933 Lansing... 123/179 2,299,464 10/1942 Coffman... 123/183 2,509,942 5/1950 Sanford 123/179 3,459,165 8/1969 Bender et a1 123/183 FOREIGN PATENTS 533,079 11/1954 Belgium 123/179 581,139 7/1933 Germany 123/179 Primary Examiner-Laurence M. Goodridge Assistant ExaminerRonald B. Cox Attorney-Hill, Sherman, Meroni, Gross & Simpson ABSTRACT: A starting system for diesel engines which sequentially provides pressured gas directly to the cylinders to initiate engine turnover. The gas is supplied either from a compressed air storage or from a chemical pressure generator capable of supplying high-pressure, high-temperature gases. The chemical pressure generator supplied gases initiate engine turnover while heating the engine to a point necessary for combustion in low-temperature environments.

/Z m s A? /7 /7 2 a 3 I 36 M 25 STARTING SYSTEM FOR DIESEL ENGINES BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to engine systems and more particularly to an auxiliary starting system for diesel engines.

2. Prior Art Many starting systems for diesel engines are well-known and include such systems as externally located inter-nal combustion engines, electric motors, turbine driven motors and the like.

The majority of such systems act, through gearing, upon the crankshaft of the diesel engine to revolve it. Additionally, it is known to use compressed air to act upon the pistons to initiate revolution of the engine. Such compressed air systems direct the air sequentially to the cylinders themselves through cylinder ports. These systems are advantageous in that air is the working medium and no wearing, mechanical parts are involved in cranking the engine. Hence starting is reliable, noiseless, efficient and the system requires little maintenance.

However, in extremely cold temperatures, where the engine has been left idle for a period of time, the prior art systems may be ineffective to initiate combustion. Combustion in a diesel engine is entirely dependent upon the heat of compression of the air charge.

When the engine structure of a diesel engine has achieved a sufficiently low temperature, attempts to initiate engine starting may be unsuccessful due to the ability of the cold engine parts to rob heat from the intake charge thereby retaining them, although in a compressed state, at a temperature insufficient to cause combustion. In compressed air starting systems which port the air directly to the cylinders, this problem may be increased due to the refrigeration effect of expansion of the high pressure starting air.

SUMMARY These deficiencies of the prior art are overcome by the present invention which provides a high-pressure, high-temperature gas generating system in combination with a cylinder ported compressed air system. The chemical pressure generator and the compressed air storage system are connected to a common supply line for supplying pressured gases to a distributor. From the distributor the gases are supplied in timed sequence to the cylinders of the engine. The compressed air supply system and gas pressure generator are actuatable independently of one another and a valve mechanism prevents backflow from one supply system into'the other.

Although the invention may be practiced in connection with any chemical pressure generator capable of generating high pressure, high-temperature gases, a preferred embodiment of the system utilizes combustion-produced gases such as are created by the combustion of an entrapped supply of propellant.

The provision of a dual source system for pressured gases wherein one of the systems provides a high-temperature gas allows the operator of the diesel engine to actuate the system which is most suitable for starting the engine dependent upon the condition of the engine. Thus, during continuous start-stop operation of a diesel engine such as may be encountered in its use in a bus or deliveryvehicle, the engine may be turned off a number of times and restarted after a short period of time by use of the compressed air system. Inasmuch as in a preferred embodiment, the compressed air system is resupplied with pressure air by an engine-driven compressor, the system is economical to operate and does not require access to an external supply independent of the vehicle. The cartridge gas source provides ideal emergency starting means in case of accidental loss of air pressure.

In those instances where it is desired to initially start the diesel engine after it has been idle for a period of time in a cold environment, the operator may actuate the chemical pressure generator system which will supply a quantity of high-pressure, high-temperature gas. In this invention, the high-temperature gas is ported directly to the cylinders through a distributor, where, in addition to turning over the engine, it will quickly heat the cylinder walls, pistons, and cylinder head to a point where combustion can occur in the individual cylinders.

It is therefore an object of this invention to provide an improved starting system for diesel engines.

It is a further object of this invention to provide a combined starting system and cylinder heating system for diesel engines.

It is a further and more detailed object of this invention to provide an individual cylinder ported starting system for diesel engines wherein high-pressure gases are ported directly to the cylinders to initiate engine turnover, the high-pressure gases being efiective to increase the temperature of the cylinders.

It is yet another and more important object of this invention to provide a combination starting system for diesel engines having a supply of compressed air and a chemical pressure generator capable of supplying high-pressure, high-temperature gases, the supplies being independent and selectively feedable to the individual cylinders of a diesel engine.

It is another and more specific object of this invention to provide a starting system for diesel engines utilizing highpressure gas which is ported directly to the cylinders of the engine by a single distribution system, the pressurized gas being alternatively supplied by one or two supply systems, the first including a compressed air storage and the second including a chemical pressure generator.

Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWING The drawing illustrates a disassembled schematic view of the dual starting system of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing illustrates a starting system 10 of this invention in connection with a diesel engine 11 having a plurality of cylinders therein. Each of the cylinders has a port 12 extending thereinto from the exterior of the engine 13. Feed lines 14 communicate with each of the ports 12.

The engine 11 also has an intake manifold 15 connected to an intake member 16 for supplying air to the cylinders for combustion therein. The diesel engine 11 operates in the standard manner and the individual pistons in the cylinders preferably fire in staggered relation from one another.

The starting system 10 includes three major subsystems, a distributor system 10a, a high-pressure air supply system 10b, and a high-pressure high-temperature gas supply system 10c. The gas supply systems 10b and are both connected to the distributor system 10a and are individually operable independently of one another and supply high-pressure gas to the distributor system for sequential distribution to the individual.

cylinders of the diesel engine 11.

Valves 17 interconnect the feed lines 14 with the ports 12. The valves 17 are one-way valves allowing flow of pressured gases from the feed-lines 14 to the cylinders and preventing back-flow during combustion in the cylinders.

The compressed air supply system 10b consists of an engine driven air compressor, air storage tanks, piping and valving substantially as follows. The power train 20 of the engine 1 1 is utilized to drive a compressor 21. The compressor 21 includes a compressing piston contained in a cylinder 23. Compressed air created by operation of the compressor 21 is fed through a line 24 to a valving and pressure regulator control schematically illustrated at 25. The compressed air is stored in pressure bottles 26 which are attached by lines 27 to the control 25. Line 28 connects the control 25 through an antiback valve 29 to a line 30.

The distributor system a consists substantially of a distributor 22 driven by and timed in accordance with the engine 11; the feed conduits l4 interconnecting the distributor with the individual valves 17, a different feed conduit for each valve, and a conduit 30. The conduit 30 provides an input line from the supply systems 10b and 100 to the distributor 22.

The distributor is timed in accordance with the firing sequence of the piston cylinders in the engine 11 and is adapted to supply compressed air from the storage tanks 26 to the cylinders through the ports 12 in a timed sequence effective to act upon the pistons to turn over the engine. Thus, the ports 12, supply lines 14 and distributor 22 act to distribute compressed air from the storage tanks 26 through the control 25, the line 28, the antiback valve 29 and the line 30 to initiate starting of the engine.

Further, the compressor 21 supplies compressed air through the line 24 and the control 25 to the storage bottles 26 during operation of the engine 11. It can therefore be seen that the combination of the lines 14, distributor 22 and ports 12 comprise a starting system for the engine while the compressor 21, the

lines

24, 28, 30, the storage bottle 26, line 27 and control 25 comprise a supply system for supplying pressured gas to the starting system.

A second and separately actuatable supply system 10c comprises a chemical pressure generator 35 which is adapted to supply high-pressure, high-temperature gas through a line 36 and antiback valve 37 to the line 30. The chemical pressure generator 35 is actuated by a switch or trigger 38 while the compressed air supply system is actuated by a valve 39. The lines 28 and 36 interfeed through the check valves 29 and 37 to a common connection box 40 open to the line 30.

Actuation of the valve 39 will release compressed air from the storage bottles 26 to the conduit 28. The compressed air from the conduit 28 feeds to the junction 40 where it opens the valve 29 and closes the valve 37. The compressed air then is fed to the distributor 22 through the conduits 30. The distributor 22 is constructed such that in any given position of the engine pressured gas will be supplied through at least one of the lines 14 to a cylinder in which the piston has previously reached the top of its stroke but has not yet reached the bottom thereof. Thus, that piston will be forced downwardly to begin the rotation of the power train. Because the distributor 22 is timed and driven by the power train 20, it will thereafter act in such a manner as to sequentially supply the engine cylinder with compressed gas. In a four-stroke diesel engine, the compressed air is preferably fed to those cylinders which are in the midst of a power or combustion stroke.

When the engine 11 is cold, the chemical pressure generator may be actuated to supply a hot-pressured gas to the cylinder, thus fulfilling the dual function of turning over the engine and of preheating the cylinders. In a preferred embodiment, the chemical pressure generator 35 is of the type which provides a combustion chamber for a molded solid propellant cartridge which, during combustion, produces extremely highpressure, high-temperature gases. A suitable cartridge may include a solid propellant of a relatively low decomposition rate, (i.e., less than 1.0 in./sec.), and a temperature around 2,000 F. such as ammonium nitrate and a rubber compound together with an igniter such as a standard shotgun shell percussion primer. The line 36 vents the combustion chamber, preferably through a pressure regulator such as a restriction 41. The conduit 36 is connected with the junction 40 through the valve 37 such that the presence ofa pressure in the line 36 will open the valve 37 while closing the valve 29. Thereafter the hightemperature, high-pressure gases are fed through the line 30 to the distributor and thence to the engine cylinders.

in those embodiments where the pressure gases emanating from the generator 35 are higher in pressure than the compressed air gases stored in the tanks 26, both systems may be actuated simultaneously to start the engine. Thus, while pressure gases coming from the generator have an initial high temperature and high pressure, they are utilized to warm the cylinders and to start the engine revolving. If the engine should fail to start at this point due to a lack of sufficient oxygen in the cylinders caused by the presence therein of the chemical pressure generator produced gas, as the pressure from the line 36 drops, the valve 29 will open, thus supplying compressed air to the cylinders in a continuing supply of pressured gas.

As a further aid to starting, a supply system 50 for supplying a high volatile fuel to the intake manifold 15 during operation of the starting system may be provided. The supply system 50 includes a storage 51 for the fuel, an actuator valve 52 therefor and a conduit 53 connecting the storage 51 to the conduit 28 upstream of the check valve 29. A second conduit 54 connects the reservoir 51 to the intake member 16. Thus, when the compressed air supply system has been actuated by the switch 39 resulting in a pressure in the conduit 28, the valve 52 may be actuated to supply a pressured enriched fuel to the intake manifold 15 of the engine 11. In those instances where both supply systems are actuated at substantially the same time, increased volatile fuel may still be supplied to the manifold while the chemical pressure generated gases are being supplied to the cylinders and the check valve 29 is thereby closed.

Although the two supply systems have been described as separately or simultaneously actuatable, it is to be understood that they may be actuated in any desired sequence and that the chemical generator 35 may be used to supply gas to start the engine in those instances where a prior unsuccessful attempt at starting the engine utilizing the compressed air system has been made. Thus, the chemical generator 35 provides a backup system for the compressed air system. Altemately, the compressed air system can be used after the chemical pressure system has been actuated to preheat the engine and where it has failed to start the engine.

It can therefore be seen from the above that my invention provides a starting system for diesel engines which supplies pressurized gases directly to the cylinders of the diesel engine to initiate turnover of the engine and which includes two separate gas supply systems for supplying a high-pressure gas to a common distributor and feed system. One of the supply systems provides a supply of compressed air from a storage area refilled by an engine-run compressor while the other supply system supplies a source of high-pressure, high-temperature gas from a chemical pressure generator, the high temperature being utilized to preheat the engine.

The supplying of the high-pressured gases directly to the engine cylinders rather than to an auxiliary starting engine increases the efficiency of the system while at the same time allowing the use of the chemical pressure generator gases to heat the engine.

Although the teachings of my invention have herein been discussed with reference to specific theories and embodiments, it is to be understood that these are by way of illustration only and that others may wish to utilize my invention in different designs or applications.

I claim as my invention:

1. In an auxiliary starting system for diesel engines, wherein pressured gas is ported directly to the cylinders of the engine in timed sequence corresponding to the differing positional movement of the pistons in the cylinders to force the pistons to move to turn over the engine, the improvement of a dual supply system for supplying the pressured gas, one of said supply systems supplying relatively low-temperature pressured gas, the other of said supply systems supplying high-temperature pressured gas (and the said systems separately actuatable) a distributor receiving gas from both systems delivering the gas in said timed sequence to the cylinders, means for separately actuating said systems to selectively supply the lowtemperature and the high-temperature pressured gases to said distributor, a high volatile fuel source pressured from the compressed air source, and a valve selectively controlling flow of pressured fuel from said fuel source to the intake manifold of the engine.

Claims

1. In an auxiliary starting system for diesel engines, wherein pressured gas is ported directly to the cylinders of the engine in timed sequence corresponding to the differing positional movement of the pistons in the cylinders to force the pistons to move to turn over the engine, the improvement of a dual supply system for supplying the pressured gas, one of said supply systems supplying relatively low-temperature pressured gas, the other of said supply systems supplying high-temperature pressured gas (and the said systems separately actuatable) a distributor receiving gas from both systems delivering the gas in said timed sequence to the cylinders, means for separately actuating said systems to selectively supply the low-temperature and the hightemperature pressured gases to said distributor, a high volatile fuel source pressured from the compressed air source, and a valve selectively controlling flow of pressured fuel from said fuel source to the intake manifold of the engine.