FUEL INJECTED ENGINE SYSTEM

• US 20130054121A1
• Filed: 08/21/2012
• Published: 02/28/2013
• Est. Priority Date: 08/24/2011
• Status: Active Grant

• Current Assignee: Walbro LLC
• Original Assignee: Walbro Engine Management LLC (Sun Capital Partners Incorporated)
• Inventors: Galka, William E., Roche, Bradley J., Speirs, David L., Swanson, Mark S., Zbytowski, Eric G., Casoni, Massimo
• Granted Patent: US 9,371,786 B2
• Time in Patent Office: Days
• US Class Current: 701/104
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 31/003 for idle speed control
• CPC Class Codes: F02D 41/062 for starting F02D41/061 takes precedence
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/3082 Control of electrical fuel pumps
• CPC Class Codes: F02D 41/32 of the low pressure type F02D41/3082 takes precedence
• CPC Class Codes: F02D 9/1035 Details of the valve housing
• CPC Class Codes: F02M 35/10216 Fuel injectors; Fuel pipes or rails; Fuel pumps or pressure regulators
• CPC Class Codes: F02M 35/162 Motorcycles; All-terrain vehicles, e.g. quads, snowmobiles; Small vehicles, e.g. forklifts
• CPC Class Codes: F02M 69/50 Arrangement of fuel distributors , e.g. with means for supplying equal portion of metered fuel to injectors F02M69/147 takes precedence
• CPC Class Codes: Y10T 29/49233 Repairing, converting, servicing or salvaging

Abstract

An engine system may include a fuel and air supply circuit and an exhaust circuit, a temperature sensor mounted on an exterior of the engine and an oxygen sensor located in the exhaust circuit. The fuel and air supply circuit may include a throttle body mounted on the engine and having a throttle valve to control the flow rate of air delivered to the engine, a fuel injector carried by the throttle body to deliver fuel to the engine and a fuel rail carried by at least one of the throttle body and the fuel injector and having an input to receive a supply of fuel and an outlet through which fuel is routed to the fuel injector. An engine control unit may be communicated with these components to control the fuel and air mixture provided to the engine as a function of the temperature and oxygen sensor outputs.

Claims

1. An engine system, comprising:

an engine having a fuel and air supply circuit and an exhaust circuit;

a temperature sensor mounted on an exterior of the engine;

an oxygen sensor located in the exhaust circuit and operable to provide a signal indicative of the oxygen content of engine exhaust gases;

a throttle body mounted on the engine and having a throttle valve to control the flow rate of air delivered to the engine;

a fuel injector carried by the throttle body to deliver fuel to the engine;

a fuel rail carried by at least one of the throttle body and the fuel injector and having an input to receive a supply of fuel and an outlet through which fuel is routed to the fuel injector; and

an engine control unit communicated with the temperature sensor, the oxygen sensor, the throttle valve and the fuel injector to control the fuel and air mixture provided to the engine as a function of the temperature sensor output and the oxygen sensor output.

2. The engine system of claim 1 wherein the engine includes an engine speed sensor and the engine control unit is communicated with the engine speed sensor to control the fuel and air mixture provided to the engine as a function of the engine speed sensor output.

3. The engine system of claim 2 which also comprises an ignition unit mounted on or adjacent to the engine and including an ignition coil and a driver circuit adapted to control generation of an ignition signal by the ignition coil where the ignition signal is communicated with a spark plug to cause the spark plug to generate a spark.

4. The engine system of claim 3 wherein the driver circuit is communicated with the engine control unit so that the driver circuit drives the ignition coil as a function of the output of the engine speed sensor.

5. The engine system of claim 1 wherein the fuel rail is rotatably carried by the throttle body and includes an anti-rotation feature to retain a desired position of the fuel rail in assembly.

6. The engine system of claim 1 wherein the engine includes at least one cooling fin and the temperature sensor is mounted on the cooling fin.

7. The engine system of claim 6 wherein the temperature sensor is retained on the cooling fin by a clip that is secured to the engine without having to form any void in the engine.

8. The engine system of claim 1 wherein the temperature sensor is retained on the engine by a clip that is secured to the engine without having to form any void in the engine.

9. A throttle body assembly for use with an internal combustion engine, comprising:

a main body including a throttle bore through which air is delivered to the engine;

a throttle valve carried by the throttle body and moveable between a first position substantially restricting air flow from the throttle bore and a second position permitting a greater flow rate of air from the throttle bore than the first position;

a fuel rail carried by the throttle body so that the fuel rail can be oriented in a plurality of positions relative to the throttle body, the fuel rail having an inlet through which fuel is received and an outlet through which fuel is routed to a fuel injector; and

a retainer that secures the fuel rail to the throttle body and retains a desired orientation of the fuel rail.

10. The throttle body assembly of claim 9 which also includes a throttle position sensor carried by the throttle body to provide an output signal indicative of the position of the throttle valve.

11. The throttle body assembly of claim 10 wherein the throttle position sensor includes a magnet carried by the throttle valve and a sensor element spaced from the magnet and responsive to the magnetic field of the magnet.

12. The throttle body assembly of claim 11 which also includes an engine control unit carried by the throttle body and wherein the sensor element is carried by the engine control unit.

13. The throttle body assembly of claim 9 wherein the fuel rail includes one or more anti-rotation features engageable by the retainer to inhibit rotation of the fuel rail.

14. The throttle body assembly of claim 13 wherein the anti-rotation features include a plurality of flat surfaces formed about a periphery of the fuel rail.

15. The throttle body assembly of claim 9 wherein a fuel injector is carried at least in part by the throttle body and includes an inlet in communication with the outlet of the fuel rail and an outlet communicated with the engine.

16. An engine, comprising:

a main body and one or more cooling fins integrally formed on at least part of the main body;

a temperature sensor coupled to a cooling fin by direct engagement of a portion of the temperature sensor with the cooling fin and without requiring any void formed in the cooling fin; and

a resilient clip having a first portion overlying part of the temperature sensor and a second portion overlying the cooling fin to trap the temperature sensor against the cooling fin under a compressive force.

17. The engine of claim 16 wherein the temperature sensor includes lead wires connected at a junction and a cover disposed over the junction.

18. The engine of claim 17 wherein the cover includes a planar surface disposed on the cooling fin and the clip holds the planar surface flush against the cooling fin.

19. A method of retrofitting an engine designed for use with a carbureted fuel supply system for use with a fuel injection fuel supply system, comprising:

attaching an engine temperature sensor to an exterior of the engine having an output signal indicative of the engine temperature;

providing an oxygen sensor in communication with an exhaust circuit of the engine where the oxygen sensor has an output signal indicative of the oxygen content of exhaust gases from the engine;

providing a throttle body with a throttle valve to control air flow to the engine;

providing a fuel injector to control fuel flow to the engine.

20. The method of claim 19 wherein the fuel injector is carried by the throttle body so that fuel and air are delivered from the throttle body to the engine.

21. The method of claim 19 wherein the engine includes an electronic control unit and the operation of at least one of the throttle valve and the fuel injector is controlled by the throttle body as a function of a signal provided by at least one of the oxygen sensor and the temperature sensor.

22. The method of claim 19 wherein the step of attaching an engine temperature sensor is accomplished without forming a void in any portion of the engine.

23. A method of operating an engine used with a fuel system having an engine position or speed sensor and an ignition module, the method comprising:

detecting engine rotation with the engine position or speed sensor;

determining the time period for engine revolutions;

comparing the time period for one engine revolution to the time period of the previous engine revolution;

determining a compression stroke from an exhaust stroke based on the compared engine revolution time periods; and

providing an ignition signal from the ignition module during the compression stroke and not during the exhaust stroke.

24. The method of claim 23 which also includes a fuel injector and wherein the fuel injector timing is controlled as a function of the determined compression and exhaust strokes.

25. The method of claim 23 which also includes an engine temperature sensor and wherein predetermined data relating to engine temperature at initial engine operation is used to adjust the flow rate of fuel delivered to the engine so the engine will be provided with a richer than normal air/fuel mixture for initial engine operation.

26. The method of claim 25 wherein after starting the engine, the number of engine revolutions immediately after the engine has started are determined and a predetermined enriched air/fuel mixture is provided to the engine based on the temperature, the number of engine revolutions and the predetermined data.

27. The method of claim 26 wherein the enrichment of the air/fuel mixture decreases to zero after 500 engine revolutions or less.

28. The method of claim 23 wherein the step of comparing the time period for an engine revolution to the time period for a previous engine revolution is performed until a predetermined number of consecutive cycles yields the same engine revolution to be indicative of the compression stroke to ensure the determination of the compression and exhaust strokes is correct before an ignition signal associated with the exhaust stroke is eliminated.

29. A method of operating an engine used with a fuel system having an oxygen sensor and an engine control unit in communication with the exhaust sensor, the method comprising:

providing a predetermined air/fuel mixture to the engine;

providing a signal from the oxygen sensor to the engine control unit indicative of the oxygen content of exhaust gas discharged from the engine;

adjusting the air/fuel mixture provided to the engine to achieve a signal from the oxygen sensor denoted lambda;

comparing the actual air/fuel mixture needed to achieve lambda=1 to the predetermined air/fuel mixture to determine a correction value;

utilizing the correction value to alter the air/fuel mixture actually delivered to the engine from the predetermined air/fuel mixture for given operating conditions.

30. The method of claim 29 wherein the air/fuel mixture is varied in operation of the engine to vary lambda both above and below lambda=1.

31. The method of claim 30 wherein lambda is varied between 0.97 and 1.03.