Lexus HS250h engine
Content
Lexus HS250h is a Japanese-made hybrid luxury car. According to official information, the abbreviation HS stands for Harmonious Sedan, which means a harmonious sedan. The car was created with care for the environment, but at the same time it is able to provide acceptable dynamics for sports driving. To do this, the Lexus HS250h uses an in-line four-cylinder internal combustion engine in conjunction with an electric motor.
Brief description of the car
The Lexus HS250h hybrid was first introduced at the North American International Auto Show in January 2009. The car went on sale in July 2009 in Japan. A month later, sales began in the United States. The car became one of the first in the segment of luxury compact sedans with a hybrid power plant.
The Lexus HS250h is based on the Toyota Avensis. The car has a bright appearance and good aerodynamics. The car combines excellent comfort and practicality. Confident driving and perfect handling are provided by an adaptive flexible independent suspension.
The interior of the Lexus HS250h is made using plant-based bioplastics. It includes castor seeds and kenaf fibers. This made it possible to take care of the environment and make the car “green”. The interior is quite spacious, and the driver and passenger seats are comfortable.
The car has a lot of highly functional electronics. The multimedia controller with touch control turned out to be very convenient to use. The center console has a retractable screen. The graphical user interface is fully thought out and provides access to a wide range of useful features. The touchpad has tactile feedback for enhanced usability.
Comfort is not inferior to the safety of the Lexus HS250h. The intelligent IHB system detects the presence of vehicles and adjusts the optics to prevent glare. Adaptive cruise control with LKA keeps the car in its lane. Lexus monitors driver drowsiness, detects collision risks and warns of obstacles in the way.
Engine under the hood Lexus HS250h
Under the hood of the Lexus HS250h is a 2.4-liter 2AZ-FXE inline-four hybrid powertrain. The motor was selected taking into account the provision of sufficient dynamic characteristics without increasing fuel costs. The ICE and electric motor transfer torque to the CVT for a smoother driving experience. The power unit operates on the Atkinson cycle and provides acceptable acceleration to the sedan.
The 2AZ-FXE engine is very noisy. To drive at normal speed, you need to keep high speeds. At the same time, a unique roar emanates from the motor, which the noise isolation cannot cope with. Car owners do not like this too much, especially considering that the dynamics do not match the volume of the power unit at all. Therefore, the Lexus HS250h with 2AZ-FXE is more suitable for measured city driving, where it behaves quietly and gently.
The 2AZ-FXE engine has an aluminum cylinder block. Cast iron sleeves are fused into the material. They have an uneven outer surface, which ensures their strong fixation and improves heat dissipation. A trochoid oil pump is installed in the crankcase. It is driven by an additional chain, which causes a decrease in the reliability of the power unit and increases the number of moving parts.
Another weak point in the design of the motor is the gears of the balancing mechanism. They are made of polymer material. This increased comfort and reduced engine noise, but led to frequent malfunctions. Polymer gears wear out quickly and the engine loses its efficiency.
Specifications of the power unit
The 2AZ-FXE engine has lightweight skirted alloy pistons, floating pins and an anti-friction polymer coating. The forged crankshaft has an offset relative to the line of the axes of the cylinders. The timing drive is carried out by a single-row chain. The rest of the specifications can be found in the table below.
Main technical characteristics of the 2AZ-FXE engine
| Parameter | Value |
|---|---|
| Number of cylinders | 4 |
| Number of valves | 16 |
| Exact volume | 2362 cm³ |
| Bore | 88.5 mm |
| Piston stroke | 96 mm |
| Power | 130 - 150 HP |
| Torque | 142-190 N*m |
| Compression ratio | 12.5 |
| fuel type | Gasoline AI-95 |
| Declared resource | 150 thousand km |
| resource in practice | 250-300 thousand km |
The engine number of the 2AZ-FXE is located directly on the platform on the cylinder block. Its location is shown schematically in the image below. Traces of dust, dirt and rust can complicate the reading of the number. To clean them, it is recommended to use a metal brush, rags.
Reliability and weaknesses
The 2AZ-FXE engine can hardly be called reliable. It has a number of design flaws that have caused problems of varying degrees of severity. Almost all car owners are faced with:
- progressive oil burner;
- pump leakage;
- sweating of oil seals and gaskets;
- unstable crankshaft speed;
- overheating of the engine.
Nevertheless, the main problem of engines is the spontaneous destruction of the threads in the cylinder block. Because of this, the cylinder head bolts fall out, the tightness is broken and coolant leaks appear. In the future, this can lead to a violation of the geometry of the block itself and the cylinder head. Toyota acknowledged the design flaw and improved the threaded holes. In 2011, a repair kit for threaded bushings was released for repair.
Maintainability of the motor
Officially, the manufacturer does not provide for a major overhaul of the 2AZ-FXE power unit. Low maintainability of engines is typical for most Lexus cars. 2AZ-FXE was no exception, therefore, in case of significant malfunctions, the best way to solve the problem is to purchase a contract motor. At the same time, the low maintainability of the 2AZ-FXE is compensated by the high reliability of the power plant.
There are difficulties with the elimination of minor troubles. Original spare parts are often not available for sale. Therefore, it is recommended to treat the motor with care. It is important to perform maintenance in a timely manner and fill in exceptionally high-quality gasoline.
Tuning engines Lexus HS250h
The 2AZ-FXE engine is not particularly prone to tuning. Many car owners recommend starting the upgrade by replacing it with a more suitable one, for example, 2JZ-GTE. When deciding to tune the 2AZ-FXE, there are several main areas:
- chip tuning;
- modernization of related systems;
- surface tuning of the motor;
- installation of a turbocharger;
- deep intervention.
Chip tuning can only slightly increase power. It removes the "stifling" of the engine by environmental standards from the factory. For a more substantial result, a turbo kit is suitable. However, a noticeable increase in power is hindered by an insufficient margin of safety of the cylinder block.
