SFI SYSTEM

Acoustic Control Induction System (ACIS)

1. The Acoustic Control Induction System (ACIS) uses a bulkhead to divide the intake manifold, creating 2 stages. The intake air control valve in the bulkhead is opened or closed to vary the effective length of the intake manifold in accordance with the engine speed and throttle valve opening angle. This increases the power output in all ranges from low to high speed.

   

   Text in Illustration

   *1	Crank Position Sensor Signal	*2	ECM
   *3	ACIS Actuator	*4	Intake Air Control Valve
   *5	Throttle Valve	-	-
   *a	Throttle Opening Angle	-	-

Air Intake Control System

1. The air intake control system switches between 2 intake air flow paths using the air intake control valve and actuator. As a result, a reduction of intake noise in the low-speed range and an increase in the power output in the high-speed range are realized.

   

   Text in Illustration

   *1	Crank Position Sensor Signal	*2	ECM
   *3	Throttle Position Sensor Signal	*4	Vacuum Tank
   *5	VSV	*6	Air Intake Control Valve
   *7	Air Cleaner Filter Element Sub-assembly	*8	Intake Air Surge Tank Assembly
   *a	Air	-	-

SPORT Mode and ECO Mode Control

1. During SPORT mode, the ECM optimizes acceleration feel by increasing the throttle valve opening angle more quickly at the beginning of accelerator pedal operation.

2. During ECO mode, the ECM optimizes fuel economy and driving performance by gently generating the motive force in comparison to accelerator pedal operation. At the same time, it supports ECO driving by optimizing the air conditioning performance.

   

Drive Start Control System

1. When abnormal driver accelerator pedal and shift operations are detected, the system limits the engine output and informs the driver.

   

   Tech Tips

   When the system is operating, even if the driver depresses and holds the accelerator pedal, engine output may increase on an uphill slope and decrease on a downhill slope. This behavior allows the system to restrict the vehicle speed and acceleration below the predetermined limit on slopes and is not a malfunction.

2. Control during Reverse Operation

   
   

   1. Responds to excessive depression of the accelerator pedal while operating in reverse.

   2. Corrects engine output according to the road grade and steering angle.

      Control Start Conditions (When all of the following conditions are met, control starts.)	Shift position is R. Accelerator pedal is depressed.
      Control Operation	Limits the engine output so the vehicle speed and acceleration are at or below a certain level.
      Control Stop Conditions	Shift position is not R. Accelerator pedal is fully released.

      

3. Control during Manual Shift Operation

   
   

   1. Responds to shift operations with the accelerator pedal depressed.

   2. Changes the limit amount according to the manual shift operation pattern.

   3. Corrects engine output according to the road grade and steering angle.

   
   

   1. Control when Starting Off from a Parked Position

      Control Start Conditions (When all of the following conditions are met, control starts.)	Shift position is changed from P to D, or P to R. Accelerator opening angle is approximately 1/5 or higher.
      Control Operation	Limits the engine output so the vehicle speed and acceleration are at or below a certain level.
      Control Stop Conditions	Shift position is P or N. Accelerator pedal is fully released.

      

   2. Control when Starting Off from a Parked Position

      Control Start Conditions (When all of the following conditions are met, control starts.)	Shift position is changed from R to D, D to R, or N to R. Accelerator opening angle is approximately 1/5 or higher.
      Control Operation	Limits the engine output so the vehicle speed and acceleration are at or below a certain level.
      Control Stop Conditions	Shift position is P or N. Accelerator pedal is fully released.

      

      Tech Tips

      
      

      • The engine output restraint level differs in the above 2 situations.

      • During control while a manual shift operation is performed (from control start until the accelerator pedal is released), the system informs the driver of the control via the multi-information display. For details, refer to the combination meter assembly.

Intake Mass Air Flow Meter Sub-assembly

1. The intake mass air flow meter sub-assembly, which is a slot-in type, allows a portion of the intake air to flow through the detection area. By directly measuring the mass and the flow rate of the intake air, the detection precision is improved and the intake air resistance is reduced.

2. This intake mass air flow meter sub-assembly has a built-in intake air temperature sensor.

   

   Text in Illustration

   *1	Platinum Hot-wire Element	*2	Temperature Sensing Element
   *3	Intake Air Temperature Sensor	-	-
   *a	A-A Cross Section	-	-
   	Air Flow	-	-

Crank Position Sensor

1. The timing rotor of the crankshaft consists of 34 teeth with 2 teeth missing. The crank position sensor outputs the crankshaft rotation signals every 10°, and the change of the signal due to the missing teeth is used to determine top-dead-center.

   

Camshaft Position Sensor

1. Magneto-Resistance Element (MRE) type camshaft position sensors (intake and exhaust) are used. To detect each camshaft (intake) position, a timing rotor that is secured to the camshaft (intake) in front of the camshaft timing gear assembly is used to generate 6 (3 high output, 3 low output) pulses for every 2 revolutions of the crankshaft. The timing rotor for each camshaft (exhaust) is part of the respective camshaft.

   

2. An MRE type camshaft position sensor consists of an MRE, a magnet and a sensor. The direction of the magnetic field changes due to the profile (protruding and non-protruding portions) of the timing rotor, which passes by the sensor. As a result, the resistance of the MRE changes, and the output voltage to the ECM changes to high or low. The ECM detects the camshaft position based on this output voltage.

   

Knock Control Sensor (Flat Type)

1. In a conventional knock control sensor (resonant type), a vibration plate is built into the sensor. This plate has the same resonance point as the knocking* frequency of the engine block. This sensor can only detect vibration in this frequency band.

   *: The term "Knock" or "Knocking" is used in this case to describe either preignition or detonation of the air fuel mixture in the combustion chamber. This preignition or detonation refers to the air fuel mixture being ignited earlier than is advantageous. This use of "Knock" or "Knocking" is not primarily used to refer to a loud mechanical noise that may be produced by an engine.

   A flat type knock control sensor (non-resonant type) has the ability to detect vibration in a wider frequency band (from about 5 kHz to 15 kHz). It has the following features:

   
   

   • A flat type knock control sensor is installed to an engine by placing it over the stud bolt installed on the cylinder block sub-assembly. For this reason, a hole for the stud bolt exists in the center of the sensor.

   • In the sensor, a steel weight is located in the upper portion. An insulator is located between the weight and a piezoelectric element.

   • An open/short circuit detection resistor is integrated in the sensor.

2. The engine knocking frequency will vary slightly depending on the engine speed. The flat type knock control sensor can detect vibration even when the engine knocking frequency changes. Due to the use of the flat type knock control sensor, the vibration detection ability is increased compared to a conventional type knock control sensor, and more precise ignition timing control is possible.

   

3. An open or short circuit detection resistor is integrated in the sensor. When the ignition is ON, the open circuit detection resistor in the knock control sensor and the resistor in the ECM keep the voltage at terminal KNK1 constant. An Integrated Circuit (IC) in the ECM constantly monitors the voltage of terminal KNK1. If an open or short circuit occurs between the knock control sensor and the ECM, the voltage of terminal KNK1 will change and the ECM will detect this and store a Diagnostic Trouble Code (DTC).

   

4. Vibrations caused by knocking are transmitted to the steel weight. The inertia of this weight applies pressure to the piezoelectric element. This action generates electromotive force.

   

   Text in Illustration

   *1	Steel Weight	*2	Inertia
   *3	Piezoelectric Element	-	-

Throttle Position Sensor

1. This non-contact type throttle position sensor uses a Hall IC, which is mounted on the throttle body with motor assembly.

   
   

   • The Hall IC is surrounded by a magnetic yoke. The Hall IC converts the changes that occur in the magnetic flux into electrical signals, and outputs them in the form of throttle valve position signals to the ECM.

   • The Hall IC contains circuits for the main and sub signals. It converts the throttle valve opening angle into electric signals that have differing characteristics, and outputs them to the ECM.

     

   Tech Tips

   The inspection method differs from a contact type throttle position sensor because a non-contact type throttle position sensor uses a Hall IC. For details, refer to the Repair Manual.

Accelerator Pedal Sensor Assembly

1. This non-contact type accelerator pedal sensor assembly uses a Hall IC, which is mounted on the accelerator pedal arm.

   
   

   • A magnetic yoke is mounted at the base of the accelerator pedal arm. This yoke rotates around the Hall IC in accordance with the amount of effort that is applied to the accelerator pedal. The Hall IC converts the changes in the magnetic flux that occur into electrical signals, and outputs them in the form of accelerator pedal position signals to the ECM.

   • The Hall IC contains 2 circuits, one for the main signal, and one for the sub signal. It converts the accelerator pedal position (angle) into electric signals that have differing characteristics and outputs them to the ECM.

     

   Tech Tips

   The inspection method differs from a contact type accelerator pedal sensor assembly because a non-contact type accelerator pedal sensor assembly uses a Hall IC. For details, refer to the Repair Manual.

Cam Timing Oil Control Valve Assembly

1. The cam timing oil control valve assembly controls its spool valve using duty-cycle control from the ECM. This allows hydraulic pressure to be applied to the camshaft timing gear assembly or camshaft timing exhaust gear assembly advance or retard side. When the engine is stopped, the cam timing oil control valve assembly (intake) will move to the retard position, and the cam timing oil control valve assembly (exhaust) will move to the advance position.

   

   Text in Illustration

   *1	Cam Timing Oil Control Valve Assembly (Intake)	*2	Spring
   *3	Sleeve	*4	Drain
   *5	Oil Pressure	*6	Spool Valve
   *7	Plunger	*8	Coil
   *a	To Camshaft Timing Gear Assembly (VVT-i Controller) (Advance Side)*	*b	To Camshaft Timing Gear Assembly (VVT-i Controller) (Retard Side)*

   *: On the cam timing oil control valve assembly (exhaust), the advance and retard sides are reversed.

Intake Air Control Valve

1. The intake air control valve is installed in the intake air surge tank assembly. It opens and closes to provide 2 effective intake manifold lengths.

2. The ACIS actuator activates the intake air control valve based on signals from the ECM.

   

   Text in Illustration

   *1

   Intake Air Control Valve

   *2

   ACIS Actuator

Ignition Coil Assembly

1. The Direct Ignition System (DIS) provides 6 ignition coil assemblies, one for each cylinder. The spark plug caps, which provide contact to the spark plugs, are integrated with the ignition coil assembly. Also, an igniter is enclosed to simplify the system.

   

   Text in Illustration

   *1	Igniter	*2	Iron Core
   *3	Primary Coil	*4	Secondary Coil
   *5	Plug Cap	-	-

Spark Plug

1. Long-reach type spark plugs are used. This type of spark plug allows the area of the cylinder head sub-assembly that receives the spark plugs to be made thick. Thus, the water jacket can be extended near the combustion chamber, which contributes to cooling performance.

2. Iridium-tipped spark plugs are used to achieve a 100000 km (60000 miles) maintenance interval. By making the center electrode of iridium, it is possible to achieve superior ignition performance and durability when compared to platinum-tipped spark plugs.

   

   Text in Illustration

   *1	Water Jacket	*2	Iridium Tip
   *3	Platinum Tip	-	-

Acoustic Control Induction System (ACIS)

1. While the engine is running at low or medium speed under high load, the ECM causes the actuator to close the control valve. As a result, the effective length of the intake manifold is lengthened and the intake efficiency, in the medium speed range, is improved due to the dynamic effect (inertia) of the intake air, thereby increasing power output.

   

2. Under any condition except when the engine is running at low or medium speed under high load, the ECM causes the actuator to open the control valve. When the control valve is open, the effective length of the intake air surge tank assembly is shortened and peak intake efficiency is shifted to the low-to-high engine speed range, thus providing greater output at low-to-high engine speeds.

   

Air Intake Control System

1. The intake control valve position is switched by the VSV depending on engine speed and throttle valve angle signals.

2. When the engine is operating in the low to mid speed range, this control operates the air intake control valve to close one part of the air cleaner inlet assembly. As a result, the air enters the air filter box via the smaller port, allowing the intake air resonator sub-assembly to help reduce intake noise.

3. When the engine is operating in the high-speed range, this control operates the air intake control valve to open both sides of the air cleaner inlet assembly. As a result, the intake area is maximized and the intake efficiency is improved.

   

Fuel Pump Control

1. The fuel pump is controlled by the ECM using the fuel pump control ECU assembly. Based on the signal received from the ECM, the fuel pump control ECU assembly controls the power supplied to the fuel pump to 3 levels (low, mid and high). Battery voltage is directly supplied to the fuel pump for high. However, for mid and low, Pulse Width Modulation (PWM) control is used to control the power supplied. This contributes to fuel economy by reducing current consumption compared to conventional control that operates by switching a resistor in and out of the circuit. Fuel pump control has fuel cut control. Fuel cut control stops the fuel pump when any of the SRS airbags has deployed.

   
   

   • When the ECM detects the airbag deployment signal from the airbag sensor assembly, the ECM will turn the EFI main relay off. After fuel cut control has been activated, turning the engine switch from off to on (IG) cancels fuel cut control, and the engine can be restarted.

   

Cooling Fan Control System

1. The cooling fan control system achieves an optimal fan speed in accordance with the engine coolant temperature, vehicle speed, engine speed, and air conditioning operating conditions. The ECM calculates the appropriate fan speed and sends the signals to the cooling fan ECU. Upon receiving the signals from the ECM, the cooling fan ECU actuates the fan motors.

   

2. As illustrated below, the ECM determines the required cooling fan speed by selecting the fastest fan speed from among the following:

   
   

   1. The fan speed required according to the engine coolant temperature (Graph 1).

   2. The fan speed required based on the air conditioning refrigerant pressure (Graph 2).

   
   

   • When the air conditioning refrigerant pressure is within the lower part of the normal operating range with the air conditioning pressure sensor on, the required fan speed differs according to the vehicle speed.

   • When the air conditioning refrigerant pressure is higher than a specified upper limit, the required fan speed will increase based on an emergency request from the ECM.

   

Starter Control (Cranking Hold Function)

1. When the engine switch is pressed, the certification ECU (smart key ECU assembly) receives a start signal.

2. When the certification ECU (smart key ECU assembly) detects a start signal (STSW), the certification ECU (smart key ECU assembly) outputs a starter relay drive signal (STAR). The signal goes through the park/neutral position switch assembly to the starter relay. The starter relay activates the starter assembly when it receives this signal. At this time, the certification ECU (smart key ECU assembly) turns off the ACC relay by turning off the power sent from the ACCD terminal. the ACC relay is turned off to prevent flickering of the meters, clock and audio system.

3. When communication between the certification ECU (smart key ECU assembly) and ECM stops, the certification ECU (smart key ECU assembly) uses the engine speed (NE) signal received from the ECM via a direct line to determine when to turn off the starter.

   

4. While cranking, the certification ECU (smart key ECU assembly) continues energizing the starter relay until it is determined that the engine has started. When the certification ECU (smart key ECU assembly) has judged that the engine has started, the certification ECU (smart key ECU assembly) stops energizing the starter relay.

5. If the engine does not start even though the starter has cranked for 30 seconds, the starter relay is turned off to protect the starter motor.

   

6. This system has the following safety features:

   
   

   • While the engine is running, the starter cannot operate.

   • The starter will stop operating once the engine has started, even if the engine switch remains pushed.

   • Starter operation is limited to a 30 seconds to protect the starter motor.