Overview
The TR sensor communicates the gear selector position the driver selects to the PCM. The PCM determines a gear mode based on the TR input and the vehicle speed signal. The PCM then broadcasts a gear mode message over the communication link. The TCM uses the gear mode message to engage the transaxle in the gear the driver selected. The other control modules use the gear mode message to control the rear lamps or a brake shift interlock solenoid. The TR sensor is mounted at the base of the gear selector assembly and the sensor shaft is moved by the selector.
Scheme 110
The EEC system provides optimum control of the engine through the enhanced capability of the powertrain control module (PCM). The EEC system also has an on board diagnostic (OBD) monitoring system with features and functions to meet federal regulations on exhaust emissions.
The EEC system has two major divisions: hardware and software. The hardware includes the PCM, sensors, switches, actuators, solenoids, and interconnecting terminals. The software in the PCM provides the strategy control for outputs (engine hardware) based on the values of the inputs to the PCM. EEC hardware and software.
This part contains detailed descriptions of the operation of EEC system input sensors and switches, output actuators, solenoids, relays and connector pins (including other power ground signals).
The PCM receives information from a variety of sensor and switch inputs. Based on the strategy and calibration stored within the PCM, the PCM generates the appropriate output. The system is designed to minimize emissions and optimize fuel economy and driveability. The software strategy controls the basic operation of the engine, provides the OBD strategy, controls the malfunction indicator lamp (MIL), communicates to the scan tool over the data link connector (DLC), allows for flash electrically erasable programmable read only memory (EEPROM), provides idle air and fuel trim, and controls failure mode effects management (FMEM).
International Standards Organization (ISO) 14229 Diagnostic Trouble Code (DTC) Descriptions
The ISO 14229 is a global, diagnostic communication standard. The ISO 14229 is a set of standard diagnostic messages that can be used to diagnose any vehicle module in use and at the assembly plant. The ISO 14229 is similar to the Society of Automotive Engineers (SAE) J2190 diagnostic communication standard that was used by all Original Equipment Manufacturers (OEMs) for previous communication protocols, like J1850 standard corporate protocol (SCP).
The ISO 14229 changes the way PIDs, DTCs, and output state control (OSC) is processed internally in the PCM and in the scan tool software. Most of the changes are to make data transfer between electronic modules more efficient, and the amount and type of information that is available for each DTC. This information may be helpful in diagnosing driveability concerns.
Vehicle Speed Functional Overview
The hybrid vehicle uses three methods to calculate vehicle speed.
Vehicle Speed From The Anti-Lock Brake System (ABS) Module
The ABS module calculates wheel speed from the front two wheel speed sensors and sends this information to the PCM through the communication network.
Vehicle Speed From The Transaxle Control Module (TCM)
The TCM calculates traction motor speed from the traction motor shaft speed sensor and combines it with (PCM stored) tire size and axle ratio data to determine vehicle speed. This calculation is then sent to the PCM over the communication network.
Vehicle Speed From Engine And Generator Speed
The TCM calculates generator speed from the generator shaft speed sensor and sends this information to the PCM. The PCM combines input information from the generator speed and engine speed along with tire size and gear ratio to calculate a vehicle speed.
The PCM strategy then cross checks all the inputs to determine if they agree with one another. If there is a discrepancy between inputs, a vehicle speed fault flag is set in the PCM and a DTC is stored.
The catalytic converter and exhaust systems work together to control the release of harmful engine exhaust emissions into the atmosphere. The engine exhaust gas consists mainly of nitrogen (N), carbon dioxide (CO 2 ) and water vapor (H 2 O). However, it also contains carbon monoxide (CO), oxides of nitrogen (NO x ), hydrogen (H), and various unburned hydrocarbons (HCs). The major air pollutants of CO, NO x , and HCs, and their emission into the atmosphere must be controlled.
The exhaust system generally consists of an exhaust manifold, front exhaust pipe, front universal heated oxygen sensor (HO2S), rear exhaust pipe, rear HO2S, a muffler and an exhaust tailpipe. The catalytic converter is installed between the front and rear exhaust pipes. Catalytic converter efficiency is monitored by the on board diagnostic (OBD) system strategy in the powertrain control module (PCM). For specific OBD catalyst monitor information, refer to the CATALYST EFFICIENCY MONITOR .
The number of HO2S used in the exhaust stream and the location of these sensors depend on the vehicle emission certification level (LEV, ULEV, PZEV). The hybrid vehicle is a partial zero emission vehicle (PZEV) equipped with two separate HO2Ss that provide input to the PCM. The first sensor in the exhaust stream before the catalyst is used for primary fuel control and the last sensor after the catalyst is used to monitor the light-off catalyst.
Scheme 111
The EVAP system prevents fuel vapor build-up in the sealed fuel tank. Fuel vapors trapped in the sealed tank are vented through the vapor valve assembly on top of the tank. The vapors leave the valve assembly through a single vapor line and continue to the EVAP canister for storage until the vapors are purged to the engine for burning.
The EGR system controls oxides of nitrogen (NOx) emissions. Small amounts of exhaust gases are recirculated back into the combustion chamber to mix with the air/fuel charge. The combustion chamber temperature is thereby reduced, lowering NOx emissions.
The EEGR system consists of an electric motor/EGR valve integrated assembly, the powertrain control module (PCM), and the connecting wiring. Additionally a manifold absolute pressure (MAP) sensor is also required. Operation of the system is as follows
- The EEGR system receives signals from the cylinder head temperature (CHT), throttle position (TP), mass air flow (MAF), crankshaft position (CKP) sensor and the MAP sensors to provide information on engine operating conditions to the PCM. The engine must be warm, stable, and running at a moderate load and RPM before the EEGR system is activated. The PCM deactivates the EEGR during idle, extended wide open throttle (WOT), or whenever a concern is detected in an EEGR component or an EGR required input.
- The PCM calculates the desired amount of EGR for a given set of engine operating conditions.
- The PCM outputs signals to the EEGR motor to move (advance or retract) a calibrated number of discrete steps. The electric stepper motor directly actuates the EEGR valve independent of engine vacuum. The EEGR valve is commanded from 0 to 52 discrete steps to get the EGR valve from a fully closed to fully open position. The position of the EGR valve determines the EGR flow.
- A MAP sensor is used to measure variations in manifold pressure as exhaust gas recirculation is introduced into the intake manifold. Variations in EGR being used correlate to the MAP signal (increasing EGR increases manifold pressure values).
Scheme 112
The fuel system supplies the fuel injectors with clean fuel at a controlled pressure. The powertrain control module (PCM) controls the fuel pump and monitors the fuel pump circuit. The PCM controls the fuel injector on/off cycle duration and determines the correct timing and amount of fuel delivered. When a new fuel injector is installed it is necessary to reset the learned values contained in the keep alive memory (KAM) in the PCM. For more information, refer to RESETTING THE KEEP ALIVE MEMORY (KAM) .
The hybrid electric system consists of three key components: the internal combustion engine, the electronically controlled continuously variable transaxle (CVT), and the high voltage traction battery. For a detailed description of each component, refer to HYBRID ELECTRIC CONTROL HARDWARE . In this powertrain configuration, there are two power sources that are connected to the driveline: a combination of the engine and the generator which uses a planetary gear set to connect to each other, and the electric traction motor which is connected to the drive wheels.
The high voltage traction battery is an electric energy storage device. The electric energy is used by the generator motor and the traction motor.
Scheme 113
The planetary gear set functions as an electronically controlled CVT between the carrier gear (engine) and the ring gear (traction motor) which is connected to the drive wheels. This is achieved by controlling the sun gear (generator) speed and direction. The reason this is an electronically controlled CVT is due to the property of the planetary gear set in which the torque relationships between the sun gear, the carrier gear, and ring gear are fixed for this mechanical design. Therefore, the planetary gear set can also be viewed as a device that splits the engine output power to the driveline and to the generator motor.
There are two paths for the engine to deliver its output power: from the engine to the carrier gear, to the ring gear, to the intermediate shaft (mechanical path), and from the engine to the carrier, to the sun gear, to the ring gear and to the intermediate shaft (electrical path). The combination of the mechanical and the electrical paths makes this powertrain similar to a conventional vehicle powertrain with a CVT.
The electric traction motor uses power supplied by the high voltage traction battery and provides propulsion to the vehicle independently from the engine. Both power sources, a combination of the engine and the generator and the electric traction motor, can propel the vehicle simultaneously and independently.
This powertrain configuration is able to achieve better than conventional powertrain fuel economy and lower emissions levels because
- the engine operates in its most efficient operating regions whenever possible.
- the engine size can be reduced with the same vehicle performance because of the dual power sources.
- the engine operation can be better optimized since it can be stopped if operational conditions are not favorable to the fuel economy or emissions.
- the kinetic energy during braking can be captured and stored in the high voltage traction battery through regenerative braking.
The torque determination and energy management strategy controls and operates the powertrain system to satisfy driver demands, increase the fuel economy, and decrease emissions levels.
In order to achieve better fuel economy and lower emission levels, the powertrain control module (PCM) torque determination and energy management strategy operates the powertrain system with specified operational conditions. First, the torque determination and energy management strategy determines in real time how much torque the driver is requesting and how much torque each power source can deliver to the drivetrain. Then it chooses the most efficient power source for that operational condition. Some of the inputs to the energy management strategy include driver demand, traction battery state of charge, performance limitations of components, battery life (charging and discharging rate and cycling), driveability, ambient temperature, and barometric pressure.
The hybrid electric system is a torque based system. When the gear selector is placed in DRIVE, the driver is going to request a positive torque by pressing the accelerator pedal, or a negative torque by pressing the brake pedal. The positive torque is perceived as vehicle acceleration, and the negative torque as vehicle deceleration (braking).
The brake and the electric power assist steering systems remain fully functional when the engine is stopped by the PCM. This allows the driver to operate the vehicle in electric mode when the engine is off.
The ignition system is designed to ignite the compressed air/fuel mixture in an internal combustion engine by a high voltage spark from an ignition coil. The ignition system also provides engine timing information to the powertrain control module (PCM) for correct vehicle operation and misfire detection.
Note. For illustrations of intake air system components, refer to INTAKE AIR DISTRIBUTION & FILTERING .
The intake air system provides clean air to the engine, optimizes air flow, and reduces unwanted induction noise. The intake air system consists of an air cleaner assembly, resonator assemblies, hydrocarbon filter and hoses. The hydrocarbon filter trap helps reduce emissions by preventing fuel vapor from escaping into the atmosphere from the intake when the engine is off. It is typically located inside the air intake system. The main component of the intake air system is the air cleaner assembly. The air cleaner assembly houses the air cleaner element that removes potential engine contaminants, particularly abrasives. The mass air flow (MAF) sensor is attached externally to the air cleaner assembly and measures the quantity of air delivered to the engine combustion chamber. The MAF sensor can be replaced as an individual component. The intake air system also contains a intake air temperature (IAT) sensor, which is integrated with the MAF sensor. For additional information, refer to POWERTRAIN CONTROL MODULE (PCM) INPUTS . The air induction resonator is a part of the intake air housing. The function of a resonator is to reduce induction noise. The air induction components are connected to each other and to the electronic throttle body assembly with hoses.
The overall quantity of air metered to the engine is controlled by the torque-based electronic throttle control (ETC) system.
For additional information, refer to TORQUE-BASED ELECTRONIC THROTTLE CONTROL (ETC) .
Note. Do not remove the PCV system from the engine. Removal of the PCV system adversely affects the fuel economy and engine ventilation and results in shorter engine life.
The PCV system cycles crankcase gases back through the induction system into the engine where they are burned. The PCV valve regulates the amount of ventilated air and blow-by gases to the intake manifold.
The hybrid vehicle uses a non-heated PCV system. PCV systems that comply with on board diagnostics (OBD) PCV monitoring requirements use a quarter-turn camlock thread design at one end to prevent accidental disconnection from the valve cover. For more information about the PCV monitor, refer to POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM MONITOR .
Scheme 114
The torque-based ETC is a hardware and software strategy that delivers an engine output torque (via throttle angle). It uses an electronic throttle body, the powertrain control module (PCM), and an accelerator pedal assembly to control the throttle opening and engine torque.
The intake phase shifting (IPS) VCT system enables rotation of the intake camshaft relative to the crankshaft rotation as a function of engine operating conditions.
The VCT system has several operational modes: idle, part throttle, wide open throttle (WOT), and default mode. At idle and low engine speeds with closed throttle, the powertrain control module (PCM) determines the phase angle based on a constant angle, limited by engine oil temperature and engine RPM. At part and wide open throttle the PCM determines the phase angle based on engine RPM, load, and throttle position. VCT systems provide reduced emissions and enhanced engine power, fuel economy and idle quality. IPS systems also have the added benefit of improved torque.
OBD Overview
The objectives of the OBD system are to improve air quality by reducing high emissions caused by emission related concerns, reducing the time between the occurrence of a concern and its detection and repair, and assisting in the diagnosis and repair of emission related problems. A malfunction indicator lamp (MIL) is required to illuminate and alert the driver of the concern and the need to repair the emission control system. A diagnostic trouble code (DTC) is required to assist in identifying the system or component associated with the concern.
The OBD system monitors virtually all emission control systems and components that can affect tailpipe or evaporative emissions. In most cases, concerns must be detected before emissions exceed 1.5 times the applicable 120,000 or 150,000 mile emission standards. Partial zero emission vehicles (PZEV) and super ultra low emission vehicles-II (SULEV-II) can use 2.5 times the standard in place of the 1.5 times the standard. If a system or component exceeds emission thresholds or does not operate within a manufacturer's specifications, a DTC is stored and the MIL is illuminated within two drive cycles.
The OBD system monitors for concerns either continuously, (regardless of driving mode), or non-continuously (once per drive cycle during specific drive modes). A pending DTC is stored in the powertrain control module (PCM) keep alive memory (KAM) when a concern is initially detected. Pending DTCs are displayed as long as the concern is present. Note that OBD regulations required a complete concern-free monitoring cycle to occur before erasing a pending DTC. This means that a pending DTC is erased on the next power-up after a concern-free monitoring cycle. However, if the concern is still present after two consecutive drive cycles, the MIL is illuminated. Once the MIL is illuminated, three consecutive drive cycles without a concern detected are required to extinguish the MIL. The DTC is erased after 40 engine warm-up cycles once the MIL is extinguished.
In addition to specifying and standardizing much of the diagnostics and MIL operation, OBD requires the use of a standard data link connector (DLC), standard communication links and messages, standardized DTCs and terminology. Examples of standard diagnostic information are freeze frame data and inspection/maintenance (I/M) readiness indicators.
Freeze frame data describes data stored in KAM at the point the concern is initially detected and the pending DTC is stored. Freeze frame data consists of parameters such as engine RPM, engine load, vehicle speed or throttle position. Freeze frame data is updated when the concern is detected again on a subsequent drive cycle and a confirmed DTC is stored; however, a previously stored freeze frame will be overwritten if a higher priority fuel or misfire concern is detected. This data is accessible with the scan tool to allow duplicating the conditions when the concern occurred in order to assist in repairing the vehicle.
OBD I/M readiness indicators show whether all of the OBD monitors have been completed since the last time the KAM or the PCM DTC(s) have been cleared. Ford stores a DTC P1000 and blinks the MIL after 15 seconds of key-on engine-off time to indicate that some monitors have not completed. In some states, it may be necessary to carry out an OBD check in order to renew a vehicle registration. The I/M readiness indicators must show that all monitors have been completed prior to the OBD check.
The following part provides a general description of each OBD monitor. In these descriptions, the monitor strategy, hardware, testing requirements and methods are presented to provide an overall understanding of monitor operation. An illustration of each monitor is also provided. These illustrations provide only a high level overview.
Each illustration depicts the PCM as the main focus with primary inputs and outputs for each monitor. The icons to the left of the PCM represent the inputs used by each of the monitor strategies to enable or activate the monitor. The components and subsystems to the right of the PCM represent the hardware and signals used while carrying out the tests and the systems being tested. The comprehensive component monitor (CCM) illustration has numerous components and signals involved and are shown generically. When referring to the illustrations, match the numbers to the corresponding numbers in the monitor descriptions for a better comprehension of the monitor and associated DTCs.
These icons are used in the (Scheme 115) of the OBD monitors.
Scheme 115
Hybrid Hardware and Monitor Operation
- The hybrid vehicle exhaust system uses two separate HO2S. The front HO2S is a universal HO2S and is the primary fuel control sensor. This sensor is the first HO2S in the exhaust stream and is referred to as the front or stream 1 HO2S. The last HO2S downstream in the exhaust system is used to monitor the catalyst and is referred to as the rear or stream 2 HO2S. For additional HO2S information, refer to the «HEATED OXYGEN SENSOR (HO2S) MONITOR»(ref-342307-S41845846272009092300000) . Typical monitor entry conditions: minimum 5 seconds since start-up at 21°C (70°F) engine coolant temperature is between 66°C - 110°C (150°F - 230°F) intake air temperature is between -7°C - 82°C (20°F - 180°F) time since entering close loop is 30 seconds inferred rear HO2S sensor temperature, minimum of 427°C (800°F) exhaust Gas Recirculation (EGR) is between 0% - 16% part throttle, maximum rate of change 0.24 volt/0.05 sec vehicle speed is between 56 - 129 km/h (35 - 80 mph) fuel level is greater than 15% air mass is between 11 - 26 g/sec (1.5 - 3.5 lb/min) engine speed is between 1,000 - 2,500 RPM engine load is between 20 - 60%
- The DTC associated with this test is DTC P0420. Because an exponentially weighted moving average algorithm is used to determine a concern, up to six driving cycles may be required to illuminate the MIL during normal customer driving. If the KAM is reset or the battery is disconnected, a concern illuminates the MIL in two drive cycles.
The cold start emission reduction monitor is an on-board strategy designed for vehicles that meet the low emissions vehicle-II (LEV-II) emissions standards. The monitor works by detecting the lack of catalyst warm up resulting from a failure to apply sufficient cold start emission reduction during a cold start.
Cold start emission reduction system monitor test operation
- DTC: P050E cold start engine exhaust temperature out of range
- Monitor execution: once per driving cycle, from start up with the cold start emission reduction monitor active
- Monitor sequence: the monitor collects data during first 15 seconds of the cold start
- Monitoring duration: the monitor completes 300 seconds after initial engine start
Misfire Monitor Operation
The low data rate (LDR) misfire monitoring system is capable of meeting the federal test procedure monitoring requirements and the full range of misfire monitoring requirements on four cylinder engines. The monitor allows for detection of any misfires that occur six engine revolutions after initially cranking the engine.