DELPHI EFI DQLQOLQHIXHOїOWHUDQGIXHOOLQH)XHOLVWKHQSXPSHG to fuel pump module. Fuel pump module regulates fuel pressure to a system operating pressure of 39 psi. Fuel is delivered from fuel pump module through high pressure fuel line into injectors, which inject fuel into intake ports. ECU controls amount of fuel by varying length of time that injectors are on. This can range from 2 to over 12 milliseconds depending on fuel requirements. Controlled injection of fuel occurs every other crankshaft revolution, or once for each 4stroke cycle. When intake valve opens, air/fuel mixture is drawn into combustion chamber,compressed, ignited, and burned.
ECU controls amount of fuel being injected and ignition timing by monitoring primary sensor signals for engine temperature, speed (RPM), and throttle position (load). These primary signals are compared to preprogrammed maps in ECU computer chip, and ECU adjusts fuel delivery to match mapped values. After engine reaches operating temperature, an exhaust gas oxygen sensor provides feedback to ECU based upon amount of unused oxygen in exhaust, indicating whether fuel mixture being delivered is rich or lean. Based upon this feedback, ECU further adjusts fuel input to reestablish ideal air/fuel ratio. This operating mode is referred to as closed loop operation.
EFI system operates closed loop when all three of following conditions are met: Ɣ2LOWHPSHUDWXUHLVJUHDWHUWKDQѓ&ѓ) Ɣ2[\JHQVHQVRUKDVZDUPHGVXIїFLHQWO\WRSURYLGHD signal (minimum 400°C, 752°F). Ɣ(QJLQHRSHUDWLRQLVDWDVWHDG\VWDWHQRWVWDUWLQJ warming up, accelerating, etc.). Typical electronic fuel injection (EFI) system and related components include:
Ɣ)XHOSXPSPRGXOHDQGOLIWSXPS Ɣ)XHOїOWHU Ɣ+LJKSUHVVXUHIXHOOLQH Ɣ)XHOOLQHV Ɣ)XHOLQMHFWRUV Ɣ7KURWWOHERG\LQWDNHPDQLIROG Ɣ(OHFWURQLFFRQWUROXQLW(&8 Ɣ,JQLWLRQFRLOV Ɣ(QJLQHRLOWHPSHUDWXUHVHQVRU Ɣ7KURWWOHSRVLWLRQVHQVRU736 Ɣ&UDQNVKDIWSRVLWLRQVHQVRU Ɣ2[\JHQVHQVRU Ɣ0DQLIROGDEVROXWHSUHVVXUHVHQVRU0$3 Ɣ:LUHKDUQHVVDVVHPEO\ DIїOLDWHGZLULQJ Ɣ0DOIXQFWLRQLQGLFDWRUOLJKW0,/RSWLRQDO Ɣ,QWDNHDLUWHPSHUDWXUHVHQVRU FUEL RECOMMENDATIONS Refer to Maintenance. FUEL LINE Low permeation fuel line must be installed on all Kohler Co. engines to maintain EPA and CARB regulatory compliance. OPERATION NOTE: When performing voltage or continuity tests, avoid putting excessive pressure on or against connector pins.
Flat pin probes are recommended for testing to avoid spreading or bending terminals. EFI system is designed to provide peak engine SHUIRUPDQFHZLWKRSWLPXPIXHOHIїFLHQF\DQGORZHVW possible emissions. Ignition and injection functions are electronically controlled, monitored and continually corrected during operation to maintain ideal air/fuel ratio. Central component of system is Engine Control Unit (ECU) which manages system operation, determining best combination of fuel mixture and ignition timing for current operating conditions.
A lift fuel pump is used to move fuel from tank through During closed loop operation ECU has ability to readjust temporary and learned adaptive controls, providing compensation for changes in overall engine condition and operating environment, so it will be able to maintain ideal air/fuel ratio. This system requires a minimum engine oil temperature greater than 80°C (176°F) to properly adapt. These adaptive values are maintained as long as ECU is not reset. During certain operating periods such as cold starts, warm up, acceleration, high load, etc., a richer air/fuel ratio is required and system operates in an open loop mode.
In open loop operation oxygen sensor output is used to ensure engine is running rich, and controlling adjustments are based on primary sensor signals and programmed maps only. This system operates open loop whenever three conditions for closed loop operation (above) are not being met. ECU is brain or central processing computer of entire EFI system. During operation, sensors continuously gather data which is relayed through wiring harness to input circuits within ECU. Signals to ECU include: ignition (on/off), crankshaft position and speed (RPM), throttle position, oil temperature, intake air temperature, exhaust oxygen levels, manifold absolute pressure, and battery voltage.
23 24 690 01 Rev. D KohlerEngines.com WARNING ([SORVLYH)XHOFDQFDXVH¿UHVDQGVHYHUH burns. 'RQRW¿OOIXHOWDQNZKLOHHQJLQHLVKRWRU running. *DVROLQHLVH[WUHPHO\ÀDPPDEOHDQGLWVYDSRUVFDQ explode if ignited. Store gasoline only in approved containers, in well ventilated, unoccupied buildings, DZD\IURPVSDUNVRUÀDPHV6SLOOHGIXHOFRXOGLJQLWHLILW comes in contact with hot parts or sparks from ignition. Never use gasoline as a cleaning agent.