Introduction
The Z 20 DMH with single overhead camshaft (SOHC), introduced for the first time, is included in the engine range for the MY 2007 Antara.
View of the Z 20 Dmh Engine
Engine Compartment - Component Location
The main engine components, relative to their location in the engine compartment are shown below.
| 1. | Air cleaner assembly |
|---|---|
| 2. | Fuel filter |
| 3. | Engine oil cap |
| 4. | Beauty cover |
| 5. | Brake fluid reservoir |
| 6. | Power steering fluid reservoir |
| 7. | Engine coolant reservoir |
| 8. | Clutch fluid reservoir (Manual transmission only) |
| 9. | Fuse box |
| 10. | Battery |
| 11. | Washer fluid reservoir |
| 12. | Engine control module (ECM) |
| 13. | Glow plug fuse box |
| 14. | Glow plug module |
| 15. | Oil level gauge |
General Description
The engine is mounted to the front cradle on the vehicle by four mounts; load bearing mounts on the right and left hand side, and torque reaction mounts to the front and rear of the engine.
The cylinder head at the top of the engine, is made of lightweight aluminium alloy and contains a combustion chamber, designed to maximize diesel combustion efficiency.
The camshaft in the cylinder head is responsible for opening four valves per cylinder by utilizing roller finger followers.
The cast iron engine block has oil and coolant passages for lubricating and cooling the inside of the block.
Cast aluminium pistons operate within the engine block and are of a bowl type design.
The crankshaft is located between the engine block and the engine bed plate. The bed plate supports the crankshaft and bearings, and helps decrease vibration on the lower side of the engine. The crankshaft bearings are cross bolted to enhance structural rigidity.
On the front end of the crankshaft there is a crankshaft sprocket which drives the oil pump and crankshaft balancer. On the rear of the crankshaft is a target wheel which sends signals to the crankshaft position sensor (CPS).
The crankshaft balancer is located between the engine bed plate and the oil pan and consists of two shafts, which revolve in opposite directions to counterbalance vibration from the crank train.
The crankshaft sprocket utilizes the timing belt to drive the camshaft sprocket, injection pump sprocket and water pump pulley.
A timing belt idler pulley sits between the camshaft sprocket and water pump pulley, while a double eccentric timing belt tensioner assists the belt tension between the crankshaft and camshaft sprockets.
The oil pump is responsible for drawing oil from the oil pan to lubricate the various parts of the engine. An oil strainer is mounted before the inlet of the oil pump to remove impurities which could clog or damage the oil pump or other engine components.
The oil pressure regulator prevents too much oil from entering the engine lubrication passages at high engine speeds.
A positive crankcase ventilation (PCV) valve, fitted to the camshaft cover via an adapter, controls the amount of blow-by gas entering the intake system.
A lightweight aluminium alloy intake manifold is fitted to the cylinder head. The opposite side of the cylinder head has the exhaust manifold which feeds the turbocharger.
A intercooler is installed on top of radiator in the engine bay and is responsible for cooling the hot compressed air generated by the turbocharger. The intercooler increases fuel efficiency and lowers CO2 emissions.
A vacuum pump mounted on the upper left side of the engine is driven by the camshaft, and provides a vacuum to the power booster and exhaust gas recirculation (EGR) valve.
Z 20 Dmh Torque and Output Curve
| A. | Torque curve |
|---|---|
| B. | Output curve |
Engine Controls
The engine control system for the Z 20 DMH uses the BOSCH EDC 16C39 engine control module (ECM) at it's core to control all engine operations. The ECM uses information from the engine sensors to effectively control the fuel and exhaust systems, and is connected to the other on board control modules via the CAN bus.
The ECM, located in the engine compartment next to the battery, constantly monitors data from various sensors and other inputs, to assure optimal driveability and economy whilst guaranteeing minimum exhaust emissions. The unit performs continuous diagnostic tests on the system to insure that the engine is operating at its most efficient.
CAN Bus
The CAN bus is a series of data communication buses that allow the on board electronic control modules to communicate with each other, or with a diagnostic tester.
The CAN bus allows the control modules to access information from each other, enabling them to work together as a functional unit and also coordinate their own operations more efficiently. Other vehicle components such as actuators, sensors and electric motors are connected to the control modules using conventional wiring.
The CAN bus supports three types of buses; high speed (HSCAN), mid speed (MSCAN) and low speed (LSCAN).
The HSCAN is used for communicating real time data such as engine torque and steering angle, while the MSCAN is typically used for infotainment display and navigation systems.
LSCAN is the only CAN bus that is able to communicate with ignition turned off, so as to enable system functions such as remote controlled central door locking and anti theft systems.
Using the data buses for communication between various control modules has several advantages over using separate wires.
The main advantages are;
- Fewer wires in harnesses and fewer plug-in terminals on the control modules contribute to a considerable weight reduction
- More efficient data exchange between the various control modules
- Improved reliability and serviceability
Diagnostic Trouble Codes
Diagnostic trouble codes (DTC's) are stored on the ECM when a malfunction in the system is detected. For each DTC, a code is allocated to signify whether the problem is an emissions related or non-emissions related fault.
When a malfunction is detected by the ECM, one of two warning lamps in the instrument panel light up. These are, the malfunction indicator lamp (MIL) and the service vehicle soon (SVS) lamp. The MIL indicates that there is an emissions related fault, while the SVS lamp indicates a non-emissions related fault. The MIL blinks continuously in the event of a severe misfire. The vehicle's electronic system will switch to an emergency running program.
Data Link Connector
The data link connector (DLC) is located under the instrument panel on the driver's side, and provides a means of accessing data from the ECM for diagnosis.
The TECH 2 diagnostic tool can be connected to the DLC to identify DTC's that have been stored by the ECM. TECH 2 can also clear stored DTC's, perform output control tests and read serial data.
• Service: Refer to the trouble code diagnosis in the service manual for the descriptions of the DTC's.
Control Systems
The Z 20 DMH diesel engine uses four glow plug heaters in each of the cylinders as an aid to starting the vehicle, and an indicator in the instrument panel provides information on the starting conditions. The plugs are operated by the glow plug unit (GCU) which is located at the front of the engine compartment. Each glow plug is energized individually, and the ECM and GCU will monitor and control the power consumption and temperature of the plugs.
The accelerator pedal position (APP) system uses two APP sensors and the on board electronic system to establish a connection between the accelerator pedal and the fuel injection control, thus, eliminating the requirement for a mechanical link between the pedal and the fuel injectors.
The APP sensors located in the accelerator pedal give the actual position of the pedal to the ECM. The ECM directly controls the acceleration and deceleration of the vehicle depending on the accelerator pedal position and several other inputs. The ECM also processes information from the APP sensors and other inputs to determine the position of the throttle plate.
The throttle plate is controlled by the throttle plate actuator. The ECM controls the actuator and can move it to control the intake air quantity for EGR system.
The diesel engine uses a turbocharger to enhance the power and performance of the vehicle. The turbocharger is equipped with vanes which are used to vary the amount of boost pressure. The ECM determines the boost pressure and air temperature in the intake manifold by monitoring the boost pressure sensor mounted on the manifold. The ECM controls the rotation and angle of the vanes, varying the boost dependent on the load requirements of the vehicle. When the engine is not under load, the vanes are open to minimize boost and exhaust back pressure. However, the ECM will close the turbocharger vanes to increase engine power and to create a high pressure, using the boost pressure actuator.
Emission Control Systems
The diesel particulate filter (DPF) system utilizes pressure ports on the front and rear of the DPF unit. The ports are connected via pressure pipes to the differential pressure sensor. The differential pressure sensor will determine when the levels of soot in the filter are at a critical stage and initiate the regeneration process accordingly.
The exhaust gas recirculation (EGR) system is designed to reduce the amount of oxides of nitrogen (NOx) created by the engine during operating periods that usually result in high combustion temperatures.
The EGR valve allows small amounts of exhaust gas to be recirculated back into the intake manifold with incoming air, thus reducing combustion temperature and pressure, and lowering the output of NOx.
The purpose of the positive crankcase ventilation (PCV) system is to remove the potentially damaging vapours that build up in the crankcase.
The PCV valve attached to the cylinder head via an adaptor, re-uses the vapours by feeding them to the turbocharger inlet.
Engine Sensors
The intake air temperature (IAT) sensor is a thermistor type (a resistor which alters its voltage based on temperature) and is an integral part of the mass air flow (MAF) sensor. The ECM determines the air temperature in the manifold by measuring the change in voltage from the IAT sensor.
The MAF sensor on the vehicle is a hot film type and is located between the air cleaner and the turbocharger inlet pipe. The MAF sensor measures the amount of air coming into the engine, while the integrated AIT sensor monitors the air temperature in the manifold. The ECM calculates the information from the MAF and IAT to maintain a constant air flow temperature.
The engine coolant temperature (ECT) sensor is a thermistor type and is required by ECM functions such as fuel injection and ignition timing. The ECT sensor is threaded to the intake manifold and accesses the engine coolant passage.
The camshaft position sensor is located on the cylinder head and detects the camshaft rotation speed. The sensor is used by the ECM to trigger the fuel injectors in the correct sequence. As the engine rotates the sensor will signal to the ECM that cylinder number one is approaching top dead centre and the timing of the injection pulse can be determined.
With the aid of the crankshaft position sensor, the ECM can determine the orientation of the crankshaft at all times. The sensor is threaded to the side of the engine cylinder block and operates in conjunction with the toothed target wheel on the crankshaft. The ECM receives voltage signals from the sensor to ascertain the actual position of the crankshaft. The ECM uses the information from the sensor to calculate ignition timing and injection pulses to send to the fuel injectors.
The oil pressure switch is threaded to the oil pump on the engine. If the ECM receives information from the switch that the oil pressure is too low, the check oil warning lamp in the instrument panel is illuminated.